Tektronix 4200A-SCS User manual

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Model 4200A-SCS

Pulse Card (PGU and PMU)

User's Manual

4200A-PMU-900-01 Rev. B March 2023

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*P4200A-PMU-900-01B*

4200A-PMU-900-01B

Pulse Card (PGU and P MU)

Model 4200A-SCS

User's Manual

Cleveland, Ohio, U.S.A.

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without the prior written approval of Keithley Instruments is strictly prohibited.

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Document number: 4200A-PMU-900-01 Rev. B March 2023

Safety precaut ions

The following safety precautio ns should be observed before using this product and any associated instrumentation. Although some instruments and accessories would normally be used with nonhazardous voltages, there are situations where hazardous conditions may be present.

This product is intended for use by personnel who recogn ize sho ck haz ards and are familiar with the safety precautions required to avoid possible injury. Read and follow all installation, operation, and maintenance information carefully before using the product. Refer to the user documentation for complete product specifications.

If the product is used in a manner not specified, the protection provided by the product warranty may be impaired. The types of product users are: Responsible body is the individual or group responsible for the use and maintenance of equipment, for ensuring that the

equipment is operated within its specifications and operating limits, and for ensuring that operators are adequately trained. Operators use the product for its intended function. They must be trained in electrical safety procedures and proper use of the

instrument. They must be protected from electric shock and contact with hazardous live circuits. Maintenance personnel perform routine procedures on the product to keep it operating properly, for example, setting the line

voltage or replacing consumable materials. Maintenance procedures are described in the user documentation. The procedures explicitly state if the operator may perform them. Otherwise, they should be performed only by service personnel.

Service personnel are trained to work on live circuits, perform safe installations, and repair products. Only properly trained service personnel may perform installation and service procedures.

Keithley products are designed for use with electrical signals that are measurement, control, and data I/O connections, with low transient overvoltages, and must not be directly connected to mains voltage or to voltage sources with high transient overvoltages. Measurement Category II (as referenced in IEC 60664) connections require protection for high transient overvoltages often associated with local AC mains connections. Certain Keithley measuring instruments may be connected to mains. These instruments will be marked as category II or higher.

Unless explicitly allowed in the specification s, opera t ing man ual, and ins trum ent labels, do not connect any instrument to mains. Exercise extreme caution when a shock hazard is present. Lethal voltage may be present on cable connector jacks or test

fixtures. The American National Standards Institute (ANSI) states that a shock hazard exists when voltage levels greater than 30 V RMS, 42.4 V peak, or 60 VDC are present. A good safety practice is to expect that hazardous voltage is present in any unknown circuit before measuring.

Operators of this product must be protected from electric shock at all times. The responsible body must ensure that operators are prevented access and/or insulated from every connection point. In some cases, connections must be exposed to potential human contact. Product operators in these circumstances must be trained to protect themselves from the risk of electric shock. If the circuit is capable of operating at or above 1000 V, no conductive part of the circuit may be exposed.

Do not connect switching cards directly to unlimited power circuits. They are intended to be used with impedance-limited sources. NEVER connect switching cards directly to AC mains. When connecting sources to switching cards, install protective devices to limit fault current and voltage to the card.

Before operating an instrument, ensure that the line cord is connected to a properly-grounded power receptacle. Inspect the connecting cables, test leads, and jumpers for possible wear, cracks, or breaks before each use.

When installing equipment where access to the main power cord is restricted, such as rack mounting, a separate main input power disconnect device must be provided in close proximity to the equipment and within easy reach of the operator.

For maximum safety, do not touch the product, test cables, or any other instruments while power is applied to the circuit under test. ALWAYS remove power from the entire test system and discharge any capacitors before connecting or disconnecting cables or jumpers, installing or removing switching cards, or making internal changes, such as installing or removing jumpers.

Do not touch any object that could provide a current path to the common side of the circuit under test or power line (earth) ground. Always make measurements with dry hands while standing on a dry, insulat ed surf ace cap able of withs tand ing the voltage being measured.

For safety, instruments and accessories must be used in accordance with the operating instructions. If the instruments or accessories are used in a manner not specifie d in the operati ng instr u cti ons , the prot ect ion provi ded by the equi pm ent ma y be impaired.

Do not exceed the maximum signal levels of the instruments and accessories. Maximum signal levels are defined in the specifications and operating information and shown on the instrument panels, test fixture panels, and switching cards.

When fuses are used in a product, replace with the same type and rating for continued protection against fire hazard. Chassis connections must only be used as shield conn ect io ns for measuring circuits, NOT as protective earth (safety ground)

connections. If you are using a test fixture, keep the lid closed while power is applied to the device under test. Safe operation requires the use

of a lid interlock.

If a

screw is present, connect it to protective earth (safety ground) using the wire recommended in the user documentation.

The symbol on an instrument means caution, risk of hazard. The user must refer to the operating instructions located in the user documentation in all cases where the symbol is marked on the instrument.

The symbol on an instrument means warning, risk of electric shock. Use standard safety precautions to avoid personal contact with these voltages.

The

symbol on an instrument shows that the surface may be hot. Avoid personal contact to prevent burns.

The symbol indicates a connection terminal to the equipment frame.

If this

symbol is on a product, it indicates that mercury is present in the display lamp. Please note that the lamp must be

properly disposed of according to federal, state, and local laws. The WARNING heading in the user documentation explains hazards that might result in personal injury or death. Always read

the associated information very carefully before performing the indicated procedure. The CAUTION heading in the user documentation explains h azard s that coul d dama ge the instrument. Such damage may

invalidate the warranty.

The CAUTION heading with the

symbol in the user documentation explains hazards that could result in moderate or minor injury or damage the instrument. Always read the associated information very carefully before performing the indicated procedure. Damage to the instrument may invalidate the warranty.

Instrumentation and accessories shall not be connected to humans. Before performing any maintenance, disconnect the line cord and all test cables. To maintain protection from electric shock and fire, replacement components in mains circuits — including the power

transformer, test leads, and input jacks — must be purchased from Keithley. Standard fuses with applicable national safety approvals may be used if the rating and type are the same. The detachable mains power cord provided with the instrument may only be replaced with a similarly rated power cord. Other components that are not safety-related may be purcha sed fr om o ther suppliers as long as they are equivalent to the original component (note that selected parts should be purchased only through Keithley to maintain accuracy and functionality of the product). If you are unsure about the applicability of a replacement component, call a Keithley office for information.

Unless otherwise noted in product-specific literature, Keithley instruments are designed to operate indoors only, in the following environment: Altitude at or below 2,000 m (6,562 ft); temperature 0 °C to 50 °C (32 °F to 122 °F); and pollution degree 1 or 2.

To clean an instrument, use a cloth dampened with deionized water or mild, water-based cleaner. Clean the exterior of the instrument only. Do not apply cleaner directly to the instrument or allow liquids to enter or spill on the instrument. Products that consist of a circuit board with no case or chassis (e.g., a data acquisition board for installation into a computer) should never require cleaning if handled according to instructions. If the board becomes contaminated and operation is affected, the board should be returned to the factory for proper cleaning/servicing.

Safety precaution revision as of June 2018.

Introduction .............................................................................................................. 1-1

Models 4220-PGU and 4225-PMU ...................................................................................... 1-1

Connections ............................................................................................................. 2-1

Introduction .......................................................................................................................... 2-1

Connection guidelines .......................................................................................................... 2-1

PMU common connections ....................................................................................................... 2-2

Shield connections .................................................................................................................... 2-2

Cable length .............................................................................................................................. 2-3

High frequency connections ...................................................................................................... 2-3

Prober chuck connections ......................................................................................................... 2-4

PGU and PMU connectors ................................................................................................... 2-4

Model 4225-RPM ................................................................................................................. 2-5

RPM input, output, and top panels ............................................................................................ 2-5

Connecting the RPM to the PMU .............................................................................................. 2-6

Mounting the RPM .................................................................................................................... 2-8

RPM diagrams for local and remote sensing............................................................................. 2-8

Using the RPM as a switch ....................................................................................................... 2-9

Two-terminal device connections ....................................................................................... 2-10

Three-terminal device connections .................................................................................... 2-12

Four-terminal device connections ...................................................................................... 2-13

Pulse source-measure connections ................................................................................... 2-15

Pulse generator connections ................................................................................................... 2-15

Using an adapter cable to connect pulse card to DUT ...................................................... 2-16

Connections to prober or test fixture bulkhead connectors ............................................... 2-16

RPM connections to DUT................................................................................................... 2-17

Two-terminal test connections ................................................................................................. 2-17

Remote sensing using RPM connections to a prober ............................................................. 2-18

PMU connection compensation ......................................................................................... 2-20

Short compensation ................................................................................................................ 2-20

Offset current compensation ................................................................................................... 2-21

Perform connection compensa tion .......................................................................................... 2-21

Enabling connection compensation ......................................................................................... 2-22

Load-line effect compensation (LLEC) for the PMU .......................................................... 2-24

Methods to compensate for load-line effect............................................................................. 2-25

How LLEC adjusts pulse output to the target levels ................................................................ 2-25

Coping with the load-line effect ............................................................................................... 2-27

LLEC maintains even voltage spacing .................................................................................... 2-27

Test considerations ................................................................................................................. 2-28

LPT functions used to configure LLEC .................................................................................... 2-29

Enable LLEC ........................................................................................................................... 2-29

Disable LLEC and set the output impedance .......................................................................... 2-30

Setting up PMUs and PGUs in Clarius .................................................................... 3-1

Introduction .......................................................................................................................... 3-1

Table of contents

User's Manual

Model 4200A-SCS Pulse Card (PGU and PMU)

Configure the PGU, PMU, and RPM using tests ................................................................. 3-1

Create a PMU project ........................................................................................................... 3-2

Configure the tests ............................................................................................................... 3-3

PMU operation modes ......................................................................................................... 3-5

PMU - all terminal parameters ............................................................................................. 3-6

Start (PMU Amplitude Sweep) .................................................................................................. 3-6

Stop (PMU Amplitude Sweep) ................................................................................................... 3-6

Step (Pulse Amplitude Sweep) .................................................................................................. 3-7

Points ........................................................................................................................................ 3-7

Base .......................................................................................................................................... 3-7

Amplitude .................................................................................................................................. 3-7

Dual Sweep (pulse) ................................................................................................................... 3-8

Force Range (PMU) .................................................................................................................. 3-8

Disable outputs at completion ................................................................................................... 3-8

Current Spot Mean High ........................................................................................................... 3-9

Current Spot Mean Low ............................................................................................................ 3-9

Measure Current Range (PMU) ................................................................................................ 3-9

Low Range .............................................................................................................................. 3-10

Current Sample Waveform ...................................................................................................... 3-10

Voltage Spot Mean High ......................................................................................................... 3-11

Voltage Spot Mean Low .......................................................................................................... 3-11

Voltage Sample Waveform...................................................................................................... 3-11

Report Timestamps ................................................................................................................. 3-11

Report Status (PMU) ............................................................................................................... 3-12

PMU measurement status ....................................................................................................... 3-12

Compensation Short Connection ............................................................................................ 3-15

Load Line Effect Compensation .............................................................................................. 3-15

DUT Resistance (R DUT) ........................................................................................................ 3-15

Max Voltage Estimator ............................................................................................................ 3-15

Threshold Current ................................................................................................................... 3-15

Threshold Voltage ................................................................................................................... 3-16

Threshold Power ..................................................................................................................... 3-16

PMU Test Settings ............................................................................................................. 3-16

Pulse Settings ......................................................................................................................... 3-16

Timing Parameters .................................................................................................................. 3-20

PMU Advanced Test Settings ................................................................................................. 3-22

PMU capacitive charging/discharging effects .................................................................... 3-35

PMU and RPM measure ranges are not source ranges .................................................... 3-37

4220-PGU and 4225-PMU output limitations ..................................................................... 3-38

Configure the PGU, PMU, and RPM using tests ............................................................... 3-38

Step or sweep multiple device terminals in the same test ................................................. 3-39

Basic troubleshooting procedure ....................................................................................... 3-41

Step 1. Verify prober connections from the PMU or RPM to the DUT ..................................... 3-41

Step 2. Verify the pulse shape ................................................................................................ 3-42

Step 3. Is the pulse level correct for each channel? ................................................................ 3-43

Step 4. Is the pulse I-V cur ve s uspe ct? ................................................................................... 3-43

Pulse card concepts ................................................................................................ 4-1

Models 4220-PGU and 4225-PMU ...................................................................................... 4-1

PMU block diagram ................................................................................................................... 4-2

Pulse modes ............................................................................................................................. 4-3

Model 4200A

of contents

-SCS Pulse Card (PGU and PMU) User's Manual Table

Pulse measurement types (PMU) ............................................................................................. 4-3

Measure modes ........................................................................................................................ 4-4

4200A-SCS power supply limitations ................................................................................... 4-5

Pulse source-measure concepts .......................................................................................... 4-8

Ultra-fast I-V tests ..................................................................................................................... 4-8

Sample rate ............................................................................................................................. 4-10

Segment Arb waveform ........................................................................................................... 4-11

Full arb waveform .................................................................................................................... 4-15

Pulse waveforms for nonvolatile memory testing .................................................................... 4-16

Waveform capture ................................................................................................................... 4-17

DUT resistance determines pulse voltage across DUT ........................................................... 4-17

Triggering ................................................................................................................................ 4-22

Measurement types ............................................................................................................ 4-25

Spot mean measurements ...................................................................................................... 4-26

Spot mean discrete readings................................................................................................... 4-26

Spot mean average readings .................................................................................................. 4-27

Waveform measurements ....................................................................................................... 4-27

Waveform discrete readings.................................................................................................... 4-28

Waveform average readings ................................................................................................... 4-29

Measurement timing ................................................................................................................ 4-30

KPulse (for Keithley Pulse Cards)........................................................................... 5-1

Keithley Pulse Application .................................................................................................... 5-1

Starting KPulse ......................................................................................................................... 5-1

KPulse setup and help .............................................................................................................. 5-2

Triggering ............................................................................................................................. 5-3

Standard pulse waveforms .................................................................................................. 5-4

Segment Arb waveforms ...................................................................................................... 5-6

Exporting Segment Arb waveform files ..................................................................................... 5-8

Custom file arb waveforms (full arb) .................................................................................... 5-9

Custom Arb file operation: Select and configure waveforms ................................................... 5-10

Custom Arb file operation: Copy waveforms into Sequencer .................................................. 5-11

Custom Arb file operation: Load waveform and turn on output ............................................... 5-12

Waveform types ...................................................................................................................... 5-13

Use the RPM to switch the SMU, CVU, and PMU ................................................... 6-1

Introduction .......................................................................................................................... 6-1

Included accessories ............................................................................................................ 6-2

Equipment required .............................................................................................................. 6-3

Update the RPM configuration in KCon ............................................................................... 6-3

Device connections .............................................................................................................. 6-4

Connection schematic ............................................................................................................... 6-4

Connect the 4200A-SCS to the DUT ......................................................................................... 6-5

Set up the measurements in Clarius .................................................................................... 6-6

Create a new project ................................................................................................................. 6-6

Add a device ............................................................................................................................. 6-7

Search for and select existing tests in the Test Library ............................................................. 6-8

Configure the vfd test ................................................................................................................ 6-9

Configure the cv-diode test ..................................................................................................... 6-11

Configure the pulse-diode test ................................................................................................ 6-13

Table of contents

User's Manual

Model 4200A-SCS Pulse Card (PGU and PMU)

Run the test ............................................................................................................................. 6-15

View and analyze the test results ............................................................................................ 6-15

PMU for pulsed I-V measurements on a MOSFET ................................................. 7-1

Introduction .......................................................................................................................... 7-1

Equipment required .............................................................................................................. 7-2

Device connections .............................................................................................................. 7-2

Connection schematic ............................................................................................................... 7-3

Set up the measurements in Clarius .................................................................................... 7-4

Create a new project ................................................................................................................. 7-5

Search for and select an existing test ....................................................................................... 7-5

Configure the test ...................................................................................................................... 7-6

Run the test and analyze the results ......................................................................................... 7-8

Testing flash memory .............................................................................................. 8-1

Testing flash memory ........................................................................................................... 8-1

Flash connection guidelines ................................................................................................. 8-2

Programming and erasing flash memory .................................................................................. 8-3

Endurance testing ................................................................................................................ 8-8

Connections for endurance testing - no switching matrix .......................................................... 8-9

Connections for endurance testing - switching matrix ............................................................. 8-11

Disturb testing .................................................................................................................... 8-12

Connections for disturb testing ................................................................................................ 8-12

Using a switching matrix .................................................................................................... 8-14

Use KPulse to create and export Segment Arb waveforms............................................... 8-14

Enter Segment Arb values into UTM array parameters ..................................................... 8-16

Direct connections to single DUT ....................................................................................... 8-17

Direct connections to array DUT for disturb testing ........................................................... 8-19

Models 4220-PGU and 4225-PMU ........................................... 1-1

In this section:

Models 4220-PGU and 4225-PMU

The 4220-PGU High Voltage Pulse Generator Unit and 4225-PMU Ultra-Fast Pulse Measure Unit are high-speed pulse-generator cards for the 4200A-SCS. The 4220-PGU provides pulse output only. The 4225-PMU provides both pulse output and pulse measurement. The PGU and PMU have similar pulse output characteristics.

Section 1

Introduction

The 4225-PMU can be paired with one or two 4225-RPM Remote Preamplifier/Switch Modules. The RPM is a remote amplifier and automatic switch. When the RPM is used as a preamplifier for the PMU, it provides additional low-current measurement ranges. When the RPM is used as a switch, it switches between the PMU, SMUs, and CVUs.

LPT functions that pertain to the PGU and PMU are documented in “LPT commands for PGUs and PMUs” in Model 4200A-SCS LPT Library Programming.

To do quick tests with minimal interaction with other 4200A-SCS test resources, you can use the Keithley Pulse Application (KPulse). KPulse is a nonprogramming alternative that you can use to configure and control the installed Keithley pulse cards. Refer to KPulse (on page 5-1 information.

The simplified circuits of the 4220-PGU and 4225-PMU pulse generators are shown in the following figure.

) for additional

Section

User's Manual

1: Introduction Model 4200A-SCS Pulse Card (PGU and PMU)

Figure 1: Simplified circuits of the PGU and PMU

1-2 4200A-PMU-900-01 Rev. B March 2023

Load-line effect compensation (LLEC) for the PMU ............... 2-24

Section 2

Connections

In this section:

Introduction .............................................................................. 2-1

Connection guidelines .............................................................. 2-1

PGU and PMU connectors ....................................................... 2-4

Model 4225-RPM ..................................................................... 2-5

Two-terminal device connections ........................................... 2-10

Three-terminal device connect ions ........................................ 2-12

Four-terminal device connections .......................................... 2-13

Pulse source-measure connections ....................................... 2-15

Using an adapter cable to connect pulse card to DUT ........... 2-16

Connections to prober or test fixture bulkhead conne ctor s .... 2-16

RPM connections to DUT ....................................................... 2-17

PMU connection compensation .............................................. 2-20

Introduction

Proper connection methods are critical to perform stable and accurate measurements using the PMU, with or without the RPM. The guidelines in this chapter help prevent pulse voltage overshoot and oscillations.

You can use the Multi-measurement Prober Cable Kits (4210-MMPC) to connect the 4200A-SCS to perform pulse I-V measurements. These kits help maximize signal fidelity by eliminating the measurement errors that often result from cabling errors. The prober cable kits include:

• 4210-MMPC-C Multi-Measurement (I-V, C-V, Pulse) Prober Cable Kit for Cascade Microtech

12000 prober series

• 4210-MMPC-S Multi-Measurement (I-V, C-V, Pulse) Prober Cable Kit for SUSS MicroTec

PA200/300 prober series

• 4210-MMPC-L Multi-Measurement (I-V, C-V, Pulse) Prober Cable Kit for Lucas Signatone

probers

• 4210-MMPC-W Multi-Measurement (I-V, C -V, Pulse) Prober Cable Kit for Wentworth

Laboratories probers

Connection guide lines

The following guidelines describe PMU common connections, shield connections, cable length, high frequency connections, and prober chuck connections for the PMUs and PGUs.

Section

User's Manual

2: Connections Model 4200A-SCS Pulse Card (PGU and PMU)

PMU common connections

Common LO for the PMU is the outer shells of the two SMA connectors. With an SMA cable connected (see following figure), common LO is the outside shield of the cable.

Figure 2: PMU common low terminals

Because pulsing requires high frequency signal propagation, reduce cable inductance by minimizing the loop area of the connection to the device under test (DUT).

Do not use the GNDU as common low for the PMU to avoid creating a large loop area. When using the GNDU, an inductive loop area is created when the HI and LO leads are separated. Fast rise times (dt), high current (di), and large inductances (L) can cause voltage overshoots, oscillations, and ringing in the high-speed measurement circuit. This is based on Lenz’s law: V = L di/dt.

Shield connections

For multiple PMU channels, you should connect the shields (common LO) from all PMU channels as close as possible to the DUT. You reduce inductance by minimizing the loop area of the shield connections. The figure in Using an adapter cable to connect pulse card to DUT (on page 2-16) and the Local sensing (on pag e 2-17) figures illustrate proper shield connection schemes using the supplied cabling.

2-2 4200A-PMU-900-01 Rev. B March 2023

Model 4200A

Connections

-SCS Pulse Card (PGU and PMU) User's Manual Section 2:

Cable length

Use the shortest possible cable length to achieve the highest frequency output, the best pulse shape, and the best results. Here are reasons to avoid using longer cable lengths:

• Longer cable lengths have longer reflection times, which can slow down transmission times.

• Longer cables may have impedance mismatches, which can cause distortions.

• Higher capacitance in longer cables causes higher capacitive charging effects during the pulse

transitions (see PMU capacitive charging/discharging effects (on page 3-35

Only use the white SMA coaxial cables that are supplied with the PMU and RPM. These are 50 Ω

cables that match the internal 50 Ω resistance of the PMU. The PMU is supplied with 6.5 ft (2 m) SMA

cables and the RPM is supplied with 8 in. (20 cm) SMA cables. Always use the 8 in. (20 cm) SMA cables with the RPM.

High frequency connections

Use these connection guidelines for high-speed testing (pulse width <1 μs).

)).

• Use cables and connectors optimized for high frequency (at least 150 MHz). The SMA coaxial

cables supplied with the PMU and RPM are rated for high frequency.

• Probe manipulators must be rated at least 150 MHz.

• Properly connect the shields of the coaxial cables and minimize the loop area of the shield

connections (see Shield connections (on pag e 2-2

)).

• Minimize cable length (see Cable length (on page 2-3)).

• Use a signal path that matches the impedance of the instrument (50 Ω). The SMA cables

supplied with the PMU and RPM are 50 Ω.

4200A-PMU-900-01 Rev. B March 2023 2-3

Section

User's Manual

2: Connections Model 4200A-SCS Pulse Card (PGU and PMU)

Prober chuck connections

When possible, avoid pulse connections to the prober chuck. If unavoidable, use these guidelines when connecting to the prober chuck:

• When making connections to the back side of the wafer, PMU functionality will be diminished.

Use caution and verify waveforms.

• Generally, the chuck adds capacitance and noise. This reduces both low-current and hig h-speed

sampling performance.

• If one of the device terminals is the back side of the wafer, then pulse only on that terminal (on

chuck) and measure at another terminal using the second channel. If possible, do not measure from the PMU channel connected to the chuck.

• For a two-terminal device, refer to Two-terminal device connections (on page 2-10), using figure

"Two-terminal device connections to a PMU using both channels" as a guide.

• For a four-terminal device, use the Four-terminal device connections (on page 2-13) to two PMUs

figure, or the Local sensing (on page 2-17) four-terminal figure as a guide (as applicable). This cabling approach permits the low-side measurement approach described in PMU capacitive

charging/discharging effects (on page 3-35).

PGU and PMU connectors

The connectors for the PGU and PMU pulse cards are shown in the following figure.

Figure 3: 4220-PGU and 4225-PMU connectors

2-4 4200A-PMU-900-01 Rev. B March 2023

Model 4200A

Connections

-SCS Pulse Card (PGU and PMU) User's Manual Section 2:

Model 4225-RPM

The 4225-RPM is a remote amplifier/switch that is used as a current preamplifier for the 4225-PMU. The RPM provides additional high-speed, low-current measurement ranges.

The RPM can also be used as a switch for the 4200-SMU, 4201-SMU, 4210-CVU, and 4215-CVU. See Using the RPM as a switch (on page 2-9

RPM input, output, and top panels

The input, output, and top panels for the RPM are shown in the following figure.

Figure 4: 4225-RPM panels

The RPM connector on the input panel connects to one of the RPM connectors (channel 1 or channel

2) on the 4225-PMU. The RPM also has inpu t connectors for a 4200-SMU or 4201-SMU (source-measure unit) and a 4210-CVU or 4215-CVU (capacitance-voltage unit).

The previous figure shows modes for the RPM LED colors. During normal Clarius operation, only the red, green, or blue lights are shown. However, other colors or color combinations are possible. For example, during the 4225-PMU self-test, the RPM LED alternates between purple and green for the majority of the test, but there is a portion of the test where the LED flashes red and green. During firmware upgrade of the 4225-PMU, the RPM LED is green, but flashes red and green near the end of the process. During firmware upgrade of the 4225-RPM, the RPM LED is blue at the start, and changes to green for the remainder of the process.

The output status of the 4200A-SCS is indicated by the Operate light on the front of the 4200A-SCS chassis.

4200A-PMU-900-01 Rev. B March 2023 2-5

Section

User's Manual

2: Connections Model 4200A-SCS Pulse Card (PGU and PMU)

RPM wiring diagram

The internal wiring diagram of the RPM is shown in the following figure. Signals from the 4200A-SCS instrument cards are routed through the RPM to the output Force and

Sense connectors. Switching is used to control which card is connected to the output. See

RPM as a switch (on pag e 2-9) for more information on switching.

The LEDs on the top panel (see the previous figure) indicate which card is connected to the output. By default, the RPM (pulse mode) is connected to the output unless a SMU or CVU is switched in.

Using the

Figure 5: Wiring diagram of the RPM

Connecting the RPM to the PMU

Turn off the system and disconnect the power cord before connecting or disconnecting the RPM to or from the PMU. Failure to do so may result in RPM or PMU damage, possibly voiding the warranty.

2-6 4200A-PMU-900-01 Rev. B March 2023

Model 4200A

Connections

-SCS Pulse Card (PGU and PMU) User's Manual Section 2:

The RPM is matched to a PMU card and channel. Make sure to connect the RPM only to that PMU card and channel. Labels on top of the RPM indicate the specific connection channel and PMU. For example, "PMU1-2" indicates PMU1, channel 2.

With system power off, use the supplied RPM cable to connect a 4225-RPM to the matching RPM channel of the 4225-PMU, as shown in the following figure.

Figure 6: 4225-PMU connection to an RPM

With an RPM installed, never make connections directly to any of the SMA connectors (CH1 and CH2) on the PMU. This may result in damage to the PMU or DUT. It may als o produce corrupt data.

After connecting or removing an RPM, always perform the procedure “Update the RPM configuration” in Model 4200A-SCS Setup and Maintenance to ensure that KCon accurately represents the present 4200A-SCS hardware configuration.

4200A-PMU-900-01 Rev. B March 2023 2-7

Section

User's Manual

2: Connections Model 4200A-SCS Pulse Card (PGU and PMU)

Mounting the RPM

When mounting the 4225-RPM, make sure that there is a minimum of 5 cm (2 in.) of space between multiple RPM base assemblies. Spacing multiple 4225-RPM or 4200-PA instruments closer than 5 cm (2 in.) from the 4200-MAG-BASE can cause the internal relays to malfunction.

RPM diagrams for local and remote sensing

The following figure shows the diagram for local sensing. The center conductor of the Force triaxial connector is connected to the high side of the device under test (DUT) while the outer shield is connected to DUT LO. The Sense connector is not used.

Figure 7: RPM wiring diagram for local sensing

The following figure shows the diagram for remote sensing. Both Sense and Force are connected to DUT HI.

Figure 8: Diagram for remote sensing

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-SCS Pulse Card (PGU and PMU) User's Manual Section 2:

Using the RPM as a switch

You can use the RPM to switch a PMU, CVU, or SMU to a DUT terminal. The RPM wiring diagram (on page 2-6) figure shows the switches. The following figure shows a typical test configuration for using an RPM as a switch for a PMU, SMU, and CVU. In general, one RPM per device terminal is recommended. By default, the PMU (with RPM) is connected to the output unless a SMU or CVU is switched in.

Figure 9: Test configuration for using RPM as a switch

Both the red cables (supplied with the CVU) and the blue cables (supplied with the optional 4210-MMPC cable kits) are 100 Ω. You can do remote sensing (on page 2-18

) using the optional

4210-MMPC cable kits with the RPMs.

Control RPM switching

Before using an RPM, configure the 4200A-SCS by doing the steps in “Update the RPM configuration” in Model 4200A-SCS Setup and Maintenance. This properly associates the instruments connected to each RPM.

There are two methods to control RPM switching:

• ITM operation using automatic switching (after doing the steps in “Update the RPM

configuration”)

• UTM testing from within the user module, use the LPT function rpm_config

You must update the RPM configuration in KCon before u sing the RPM to control switching. If you do not, corrupt test data may result du e to incorrect switch settings in the RPM.

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2: Connections Model 4200A-SCS Pulse Card (PGU and PMU)

Two-terminal device connections

The following figure shows connections to a two-terminal device using a single channel. Connect one end of the device to the center conductor of Ch 1 and connect the other side to pulse card common (outside shield of the SMA cable).

Figure 10: Two-terminal device connections to a pulse card using one channel

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-SCS Pulse Card (PGU and PMU) User's Manual Section 2:

You can also connect a two-terminal device to the two channels of a PMU, as shown in the following figure. In this case, channel 1 will source/pulse voltage, and channel 2 will measure the resulting current. Make sure you connect the shields of the SMA cables close to the device under test. This method avoids problems of capacitive charging (see PMU capacitive charging/discharging effects

(on

page 3-35)).

Figure 11: Two-terminal device connections to a PMU using both channels

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Three-terminal device connections

A three-terminal device can be connected using either two or three PMU channels, depending on if source and/or measuring must be performed at each device pin. An example of both channels of a single PMU connected to a three-terminal MO SF ET is show n in the following figure. In this example, connect the gate terminal to channel 1 of the PMU and connect the drain terminal to channel 2. Connect the source terminal to the outside shield of channel 2.

Figure 12: Three-terminal dev ice connections to a PMU using both channels

If ultra-fast I-V sourcing and measuring is required at each device terminal, then a second PMU is required for the source terminal. Up to four PMUs (eight channels) can be installed in one 4200A-SCS mainframe.

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Four-terminal device connections

To test a four-terminal device, two PMUs are usually required. The following figure shows the four PMU channels connected to a four-terminal MOSFET. This configuration enables you to have complete flexibility to enable pulsing and measuring at any terminal on the device. Notice that the shields of the SMA cables from all four channels are connected as closely as possible to the device under test.

Figure 13: Four-terminal devic e conn ection to two PMUs

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2: Connections Model 4200A-SCS Pulse Card (PGU and PMU)

The following illustrates the connection to a 4-terminal device using the cabling and adapters that are included with either RPM or the 4225-PMU.

Figure 14: RPM output connection to 4-terminal device

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Pulse source-measure connections

TRIGGER OUT of a pulse generator card can be connected to TRIGGER IN of other pulse generator cards to synchronize the start of pulse outputs. For details on using the trigger connectors, refer to

Triggering (on page 4-22

The cables used for SMU connections are supplied with the SMUs and preamplifiers.

To achieve optimum performance, only use the cables, connectors, and adapters that are included with Keithley Instruments pulse source or measure kits.

For the pulse source-measure configura tions, ensure the 4200A-SCS high voltage is disabled. This will prevent a safety hazard that could result in possible injury or death because of SMU voltages greater than 42 V being applied to the device under test or fixture.

Pulse generator connections

The following figure shows a system that uses basic 2-channel pulse generator connections to DUTs.

Use a torque wrench to tighten SMA connections to 8 in. lb.

Figure 15: Basic pulse generator connections

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White SMA cable (2 m (6.5 ft), included with the PGU and PMU)

SMA to SSMC Adapter Cable (4200-PRB-C, included with the PGU and PMU)

2: Connections Model 4200A-SCS Pulse Card (PGU and PMU)

Using an adapter cable to connect pulse card to DUT

The following figure shows an example of how to make pulse card connections to the device under test (DUT) using the supplied SMA to SSMC adapter cable.

Figure 16: Pulse card connections using the SMA to dual SSMC adapter cable

A B

The needle holders shown in the previous figure are supplied by the user.

Connections to prober or test fixture bulkhead connectors

The 4200-PMU-Prober-Kit (available from Keithley Instruments) is a collection of standard and custom connectors and accessories used to connect the pulse generator to a common variety of probe stations. This kit can also be used for pulse card connections to a test fixture.

The following figure shows an example of how a PMU or PGU can be connected to a triaxial connector of a prober or test fixture.

If connecting to a prober or test fixture that uses BNC connectors, adapter C is not used.

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White SMA cable (2 m (6.5 ft) included with the PGU or PMU)

SMA socket to BNC plug (included with the 4200-PMU-Prober-Kit)

BNC socket to three-lug triaxial plug (included with the 4200-PMU-Prober-Kit)

-SCS Pulse Card (PGU and PMU) User's Manual Section 2:

Figure 17: Pulse card connections to triaxial prober or test fixture

A B C

RPM connections to DUT

With an RPM installed, never make connections directly to any of the SMA connectors (CH1 and CH2) on the PMU module. This may result i n dama g e to the PMU or DUT or may produce corrupt data.

A device under test (DUT) can be tested using local sensing or remote sensing. Local sensing is performed at the RPM, while remote sensing is performed at the DUT. When using remote sensing, errors due to voltage drops in the Force path between the RPM and the DUT are eliminated. With proper cabling, SMU or CVU tests provide remote sensing through the RPM.

Two-terminal test connections

For local sensing, only the Force output terminal of the RPM is connected to the DUT. The Sense output terminal is not used. The following figure shows local sense connections using the supplied adapter cable and adapters. For the two-terminal test shown in the followin g figure , the loca l ground is left unconnected. Test circuit low is connected to the shield of the Force connector through the cables.

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Triaxial plug to BNC socket adapter (supplied with the RPM)

BNC plug to SMA socket adapter (supplied with the RPM)

White SMA cable, 20.32 cm (8 in.) (supplied with the RPM)

SMA to SSMC adapter cable (4200-PRB-C, supplied with the PMU)

2: Connections Model 4200A-SCS Pulse Card (PGU and PMU)

Figure 18: Two-terminal local sense connections using the SMA to SSMC adapter cable

This connection method eliminates the triaxial guard (inner shield).

A B C D

The needle holders shown in the previous two figures are supplied by the user.

When using two RPMs for four-terminal testing, two Y-cable assemblies are required. Make sure to connect the two local grounds of the two cable assemblies together (see the figure in

connections to a prober (on page 2-18)).

Remote sensing using RPM connections to a prober

Optional prober cable kits are available from Keithley Instruments. These kits provide connections to a DUT:

• Model 4210-MMPC-S: Use this cable kit with the Suss Micro Tec PA200/300 series prober.

• Model 4210-MMPC-C: Use this cable kit with the Cascade Microtech 12000 series prober

(manipulator type DCM-200 series).

RPM

• Model 4210-MMPC-L: Use this cable kit with a Lucas Signatone Wavelink series prober.

• Model 4210-MMPC-W: Use this cable kit with the Wentworth prober.

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BNC plug-to-SMA socket adapter (supplied with the RPM)

White SMA cable (20.32 cm (8 in.), supplied with the RPM)

SMA-to-SSMC Adapter Cable (4200-PRB-C, supplied with the PMU)

-SCS Pulse Card (PGU and PMU) User's Manual Section 2:

Figure 19: RPM connections to a prober

Triaxial plug-to-BNC socket adapter (supplied with the RPM)

B C D

For details on using these prober cable kits, refer to PA-1000 for the Suss prober, PA-1001 for the Cascade prober, PA-1080 for the Lucas Signato ne pro ber , and PA-1085 for the Wentworth prober.

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2: Connections Model 4200A-SCS Pulse Card (PGU and PMU)

PMU connection compensation

You can correct errors caused by connections and cable length between the 4225-PMU and the device under test (DUT) by using connection compensation. When connection compensation is enabled, the default or measured compensation values are factored into each DUT measurement.

Connection compensation includes short and offset current compensation options. You have the option to use either default connection compensation values (PMU or RPM) or custom

connection compensation values. The default values can be used for typical connection setups that use the supplied cables. The custom connection compensated values are generated when connection compensation is done from the Clarius software. The custom values provide optimum compensation. Custom connection compensation data is generated for offset current and short conditions. The custom connection compensation values can be enabled or disabled from a test in Clarius.

If connection compensation is disabled, the compensation values will not be applied to the measurements.

For optimum performance, you should do connection compensation any time the connection setup is changed or disturbed. Changes in temperature or humidity do not affect connection compensation.

Short compensation

For UTMs, the default connection compensation values for short can only be enabled using the LPT function pulse_conncomp.

You can perform short compensation to remove measurement errors due to stray resistance in your test configuration. When you run short connection compensation, the following status messages are generated:

• Starting PMU Cable Compensation...

• R = % Ohms

• PMU Cable Compensation complete.

• % = value (V and I measured, Ohms calculated).

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Offset current compensation

Error currents can be introduced into your pulsed measurements setup by PMUs. PMU offset compensation reduces error currents by subtracting measurements taken at 0 V from all subsequent readings.

Perform connection compensation

To compensate for connections:

1. In Clarius, select Tools. The Clarius Tools dialog opens.

Figure 20: Clarius Tools dialog

2. Select PMU Connection Compensation. The Short and Offset Current Connection Compensation Values and Defaults dialog opens.

3. From the PMU list, select the PMU that you want to perform compensation for.

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Figure 21: PMU Connection Compensation dialog

4. To perform short connection compensation, select Measure Short, then follow the on-screen instructions or replace the DUT in the test fixture with a short.

5. To perform offset current compensation, select Measure Offset, then follow the on-screen instructions.

Compensation results are displayed when compensation is complete. If an error occurred, it is displayed in the Clarius Messages area. The compensation data is displayed in the Short and Offset Current Connection Compensation Values and Defaults dialog.

If your test setup uses both PMU channels, you will have new custom data for both channels.

Enabling connection compensation

This procedure is for ITMs. For UTMs, you need to enable connection compensation data using the LPT command pulse_conncomp or setmode functions.

To apply the connection compensation data to DUT measurements, you must enable connection compensation for the test.

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To enable connection compensation:

1. Select the test.

2. Select Configure.

3. Select the terminal to be compensated.

4. In the right pane, select Terminal Settings.

5. Select Advanced. The PMU Advanced Terminal Settings dialog is displayed.

6. Select either Short Connection or Offset Current Correction. Refer to the following figure.

Figure 22: Enabling connection comp ensation

7. Select OK.

8. To disable connection compensation, clear either Short Connection or Offset Current Correction, then select OK. When disabled, connection compensation values are not applied to DUT measurements.

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Load-line effect compensation (LLEC) for the PMU

Load-line effect compensation (LLEC) is only performed for standard pulse I-V testing using PMU measure ranges. It is not performed when using 4225-RPM measure ranges (≤10 μA). The active RPM circuitry provides its own analog LLEC (assuming there is a short cable from the RPM to the DUT).

The basic pulse output system is a series circuit that consists of the pulse generator resistance (fixed at 50 Ω), interconnect (cabling and pin-to-pad) resistance, and the resistance of the DUT. In this series circuit, the sum of the voltage drops across these components is equal to the output voltage of the pulse generator. Therefore, if the resistance of the DUT changes, the voltage seen at the DUT also changes. This effect is called the load-line effect. See

across DUT (on page 4-17) for details on how the resistance of the DUT affects the voltage across it.

For example, consider a PMU set to output voltage to a 50 Ω load (DUT). For this default setting, the

pulse card outputs twice the programmed pulse voltage. If the interconnect resistance is negligible (0 Ω), half the pulse card voltage appears across the internal pulse card resistance (50 Ω) and the other half (which is the programmed pulse voltage) appears across the 50 Ω DUT. For example, if the pulse card is programmed to output a 5 V pulse, the pulse card sources a 10 V pulse. Five volts will drop across the internal 50 Ω pulse card resistance and 5 V will appear at the 50 Ω DUT.

DUT resistance determines pulse voltage

The 4225-RPM also exhibits the load-line effect. The RPM has resistance in series with its output (typically between 20 Ω and 50 Ω).

Descriptions of the LPT functions discussed in the following topics are provided in Model 4200A-SCS LPT Library Programming.

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Methods to compensate for load-line effect

The methods to compensate for load-line effect include:

• Use the built-in load-line effect compensation (LLEC) in the PMU for the standard 2-level pulse

mode. Ideally (when LLEC is enabled), the PMU adjusts its output levels such that the programmed output voltage appears at the DUT. For ITMs, see Load-line effect compensation (on page 2-24). For UTMs, use the LPT pulse_meas_sm function to control LLEC.

• Manual adjustment of the PMU output until the target pulse level is measured across the DUT.

For a pulse sweep, this manual process must be repeated for every step in the sweep.

If you are not using LLEC, you can manually set the output impedance to match the impedance of the DUT. For example, if the impedance of the DUT is 1 kΩ, set the output impedance to 1 kΩ. Maximum power transfer is achieved when the DUT impedance matches the output impedance setting. In a real test environment, you may not know the exact resistance value of the DUT, and you will have the added affect of cabling and pin-to-pad resistance. The output impedance can be set from an ITM (see

Disable LLEC and set the output impedance (on page 2-30

pulse_load function).

)) or from a UTM (see the LPT

How LLEC adjusts pulse output to the target levels

LLEC is an algorithm that adjusts the output of a PMU channel. When enabled, the algorithm performs a set number of iterations in an attempt to output the target voltage to the DUT.

The algorithm used for LLEC is shown in the following figure. The diagram shows that the PMU standard pulse source (with measure) uses a burst-measure-analyze-reburst method. This method allows for range changing, threshold comparison, load-line effect compensation, and pulse timing. This means there is separation between each set, or burst, of pulses. The number of pulses output for each attempt is controlled by the Number of Pulses setting for ITMs or the pulse_meas_timing function for UTMs. Note that LLEC is available only in the standard 2-level pulse mode. LLEC is not available in the Segment Arb mode.

Note that after the first action, "Output Pulse Burst," all pulse channels in the test stop pulsing and output 0 V while performing the actions in the remaining boxes in the diagram. The time between pulses is determined by the time required to process the measurements and perform the calculations and comparisons shown in the previous figure. Wider pulses, longer pulse periods, and a higher number of pulses increases the time between pulses where the output is at 0 V. Note that both Pulse I-V and Waveform Capture Test modes use this algorithm and both will output 0 V between pulses for each step in a sweep. For strict control over the pulse voltage versus time, see the Segment Arb feature of the PMU.

The "Get Good Measurement" step shown in the previous figure also must ensure that the current measure range is correct (if ranging is enabled) and check the measured voltage and current against the thresholds. See PMU - all terminal parameters (on page 3-6

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Figure 23: LLEC algorithm for two-level pulsing (PMU)

There are two parameters that control how the LLEC algorithm functions: Maximum number of iterations and tolerance window. For IT Ms, the maximum number of iterations is fixed at 20 and the tolerance window is 0.3 percent. For UTMs, use the setmode function. The LLEC algorithm iterates, trying to reach the target voltage until one of the following occurs:

• The target voltage is reached (within tolerance specified).

• The maximum number of iterations is reached. The maximum number of iterations must be equal

for each channel in the test.

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Coping with the load-line effect

There are several ways of working with this effect. The simplest one is to program the DUT load into the pulse card channel using the pulse_load function, or setting the Pulse Load value in the KPulse

(on page 5-1) virtual front panel. The pulse card calculates the appropriate V

pulse waveform, specified by pulse_vlow and pulse_vhigh, has the correct levels. This

DUT

works well for high impedance devices or device terminals (R on a CMOS field effect transistor (FET). Unfortunately, many times R example of a varying R from point-to-point and sweep-to-sweep.

There is basically only one way to handle this situation, with two different levels of implementation. In general, assume the DUT is a FET. If the test consists of a single or limited number of gate and drain test points, the necessary voltages can be determined by pre-characterizing each unique set of test conditions.

This pre-characterization requires some way to measure the pulse heights, which is typically done using an oscilloscope and an iterative trial and error approach. Each test voltage needs to be measured, with the pulse levels adjusted until the correct voltage is reached. Record each pulse level required to reach the required V

is the drain-source resistance during a VD-ID sweep, where RDS is changing

DUT

levels.

DUT

to output so that the

INT

= 1 kΩ), such as the gate terminal

DUT

is not known or varies. A key

DUT

For information on the LPT commands listed above, refer to Model 4200A-SCS LPT Library Programming.

The 4225-PMU has built-in load-line effect compensation. For details, see Load-line effect

compensation (LLEC) for the PMU (on page 2-24).

LLEC maintains even voltage spacing

Another advantage of using LLEC is that it maintains even voltage spacing during the test. For example, if the pulse sweep uses 250 mV steps, DUT voltage and current measurements will be performed at every 250 mV step. Data that is generated using even voltage spacing is ready to be fed into a mathematical model.

When not using LLEC, uneven voltage spacing may result due to load-line effect. The following figure shows load-line effect on a FET family of curves. The blue curves were generated with LLEC enabled and the green curves were generated with LLEC disabled. The Vg was increased for the green curves to provide separation between the curves.

In the following figure, each blue curve (LLEC on) is the result of a sweep from 0 to 6 V using 250 mV steps. Notice that the 24 pulse-measure points are evenly spaced.

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Figure 24: Load-line effect on FET fami ly of curves

The same sweep is used to generate the green curves (LLEC off). The best green curve is the one at the bottom (bias V

= 2.5 V). However, load-line effect prevents the PMU from sourcing 6 V to the

DUT and the 24 pulse-measure points are not evenly spaced. Modifying the sweep to 0 to 6.5 V will ensure that at least 6 V is output to the DUT, but voltage spacing will still be uneven. The green curves for the other two bias voltages (V load-line effect.

Test considerations

The magnitude of the pulse steps affects overall test time. Wider pulses, a higher number of pulses, and larger voltage steps at each sweep point, all increase the amount of time required for the LLEC algorithm at each sweep point, which lengthens the overall test time.

There may be some high-gain devices that will not test properly with LLEC enabled. In this case, you can disable LLEC. To disable LLEC in ITMs, see Disable LLEC and set the output impedance page 2-30). For UTMs, see the pulse_meas_sm and pulse_meas_wfm functions.

= 3.0 V and 3.5 V) are even more adversely affected by

(on

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-SCS Pulse Card (PGU and PMU) User's Manual Section 2:

Figure 25: Curve showing poor LLEC compen sation

LPT functions used to configure LLEC

• The LPT functions used to configure LLEC for the PMU are:

• pulse_load: Use this function to set the output impedance for the DUT when LLEC is disabled.

Setting the DUT resistance is useful when the DUT resistance is known and is relatively constant

• setmode: Use this function to set the number of iterations for the LLEC algorithm or the tolerance

window that determines if load-line effect compensation is reached. The tolerance window is expressed as a percentage of the target voltage. The maximum number of iterations sets the maximum number of iterations that will be attempted by the LLEC algorithm. If the algorithm does not reach the target window, the measurements from last attempt are returned.

• pulse_meas_sm and pulse_meas_wfm: Use these functions to enable or disable LLEC.

Enable LLEC

This option is available for ITMs.

To enable LLEC:

1. Select the pulse test.

2. Select Configure.

3. In the right pane, select Terminal Settings.

4. Select Advanced.

5. Select Load Line Effect, as shown in the following figure.

6. Select OK.

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Figure 26: Enabling LLEC

Disable LLEC and set the output impedance

These options are available for ITMs. With LLEC disabled, you can input the known resistance of the DUT. The resistance value is then

used in a compensation process to output the voltage. The Max Voltage Estimator is a tool that you can use to calculate the maximum voltage and current

based on the selected voltage range and the entered DUT resistance value. The estimator does not affect the pulse output.

For a more accurate maximum voltage estimate, add the interconnect resistance to the DUT resistance value. The typical resistance of a white SMA cable is 0.75 Ω and the typical prober pin-to-pad resistance is 1 Ω to 3 Ω. Poorer pin-to-pad contacts could be in the range from 10 Ω to 15 Ω.

The LLEC setting does not change the maximum output voltage or current of the PMU. The V Max and I Max values are the maximum output of the PMU and are valid if LLEC is enabled or disabled. The DUT Resistance setting also does not affect the maximum output voltage. For example, the 10 V range can output 10 V into a high-impedance DUT (1 MΩ) and a lower voltage into lower impedance DUTs. Refer to DUT resistance determines pulse voltage across DUT (on page 4-17 calculating DUT resistance.

To disable LLEC and set the output impedance:

) for detail on

1. To disable LLEC, clear Load Line Effect.

2. In the DUT Resistance box, enter the resistance value.

3. Review the Max Voltage Estimator val ues.

4. Select OK.

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Basic troubleshooting procedure ............................................ 3-41

Section 3

Setting up PMUs and PGUs in Clarius

In this section:

Introduction .............................................................................. 3-1

Configure the PGU, PMU, and RPM using tests ...................... 3-1

Create a PMU project ............................................................... 3-2

Configure the tests ................................................................... 3-3

PMU operation modes ............................................................. 3-5

PMU - all terminal parameters .................................................. 3-6

PMU Test Settings ................................................................. 3-16

PMU capacitive charging/discharging effects ......................... 3-35

PMU and RPM measure ranges are not source ranges ......... 3-37

4220-PGU and 4225-PMU output limi tati ons ......................... 3-38

Configure the PGU, PMU, and RPM using tests .................... 3-38

Step or sweep multiple device terminals in the same test ...... 3-39

Introduction

This section provides basic information on creating a PMU project in Clarius and specific information on the options available for PMUs and PGUs.

For additional detail on working with Clarius, refer to the Model 4200A-SCS Clarius User's Manual.

Configure the PGU, PMU, and RPM using tests

To configure and control the PGU, a user test module (UTM) is needed. You can also use UTMs to configure and control the PMU and RPM preamplifier. For UTM programming, see “LPT commands for PGUs and PMUs” in Model 4200A-SCS LPT Library Programming.

You can use interactive test modules (ITMs) to configure and control a PMU and RPM preamplifier. Refer to “Configure a simple test” in Model 4200A-SCS Clarius User's Manual for information on configuring an ITM for the PMU.

An ITM automatically controls the RPM based on the type of test (pulse, CV, SMU). RPM switching can only be controlled using the rpm_config LPT function in a UTM. For details, refer to

RPM as a switch (on pag e 2-9).

Using the

For automatic switching of the RPM in ITMs, the RPM must already have all instrument cabling connected and recognized by the system. Information on performing this update is in “Update the RPM configuration” in Model 4200A-SCS Setup and Maintenance.

Section

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3: Setting up PMUs and PGUs in Clarius Model 4200A-SCS Pulse Card (PGU and PMU)

Create a PMU pro ject

To create a new project:

1. Select Save to save your existing project.

2. Choose Select.

3. Select the Projects tab.

4. In the Search box, type PMU and select Search. The Library displays projects that are set up for PMUs.

5. Select Create for the project you want to open. The project replaces the previous project in the project tree.

Figure 27: Filter and search for the bjt project

6. Assign a new title to the project by selecting Rename and then entering and appropriate name.

7. Select Enter.

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-SCS Pulse Card (PGU and PMU) User's Manual Section 3:

Configure the tests

To configure a test:

1. Select Configure.

2. From the Key Parameters pane, adjust the pulse voltage sweep levels of PMU1-2 on the Drain terminal and the Pulse Step Voltage of PMU1-1 on the Gate terminal, as needed.

Figure 29: Key Parameters pane for the pulse-vds-id test

Figure 28: Configure highlighte d

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3. From the Test Settings pane and Advanced Test Settings dialog, adjust the Pulse Settings and Timing Parameters as needed.

Figure 30: Test Settings pane and Test Settings Advanced dialog

4. From the Terminal Settings pane and Advanced Terminal Settings dialog, you can adjust the voltage source and current measurement parameters, as needed.

Figure 31: Terminal Settings pane and Terminal Settings Advanced dialog

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PMU operation modes

The operation mode determines what type of test is run on the terminal. Selecting the appropriate mode simplifies configuration options.

A Pulse Sweep and Pulse Step function are identical. However, in a test where two or more PMUs are used, the sweep for one PMU is performed on each step of the pulse step of the other PMU. A pulse step requires that at least one channel be configured for Pulse Sweep.

A Pulse Train outputs one or more pulses of the same magnitude and base level. The DC Gnd operation mode is used for the PMU GND terminal. When there are two or more PMUs in the test system, the Sweep Master (on page 3-20

) option is

used to select one of them as the master PMU.

Figure 32: Pulse operation modes

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Figure 33: Pulse train

When DC Bias operation mode is selected, the PMU outputs the dc base voltage. The following figure shows a representation of a dc voltage waveform.

Figure 34: DC Bias waveform

The terminal settings available for each operation mode are described in the following topics.

PMU - all terminal p arameters

When you select All Parameters, the Configure pane displays all available parameters for the test that is selected in the project tree.

Parameter descriptions are provided in the following topics.

Start (PMU Amplitude Sweep)

The voltage source level at which the sweep starts.

Stop (PMU Amplitude Sweep)

The voltage source level at which the sweep stops.

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Step (Pulse Amplitude Sweep)

The voltage size of each step of the sweep. The source level changes in equal steps of this size from the start level to the stop level. A measurement is made at each source step (including the start and stop levels).

Clarius never steps the force voltage beyond the value specified by the stop parameter, even if you specify a step value that is larger than the stop value.

Use a step value that does not result in a fractional number of points. If the point is fractional, the step value is forced to a value that results in a whole number of points. To calculate the points:

The points are rounded to the nearest value. For example, if Start = 0 V, Stop = 5 V, and Step = 0.6 V:

In this case, the Step value is forced to 0.625 V, which results in a point value of 9.333, which is rounded to 9. The instrument forces nine voltages at 0 V, 0.625 V, 1.25 V, 1.875 V, 2.5 V, 3.125 V,

3.75 V, 4.375 V, and 5 V.

Points

The number of points that are measured. This value is calculated by Clarius using the information entered for the Start, Stop, and Step parameters, using the following equation:

Base

The voltage offset (from 0 V) that is the reference for the pulse amplitude.

Amplitude

The amplitude voltage.

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Dual Sweep (pulse)

When you select Dual Sweep, the instrument sweeps from start to stop, then from stop to start. When you clear Dual Sweep, the instrument sweeps from start to stop only.

The amplitude, base, and dc sweeps have an option for Dual Sweep. The figure below shows the difference between a single pulse sweep and a dual pulse sweep. This figure illustrates a linear voltage sweep; 0 V to 4 V in 1 V steps.

Figure 35: Single and dual pulse amplitude sweep examples

Force Range (PMU)

The range that is used when sourcing. Select one of the listed ranges. The source remains on the range that is set. If you are sweeping and a sweep point exceeds the source range capability, the source outputs the maximum level for that range. This range must be equal to or greater than the largest value in the sweep.

Note that the 40 V range has a higher maximum output voltage and current, but does not have the faster transition times of the 10 V range or the lower current measure ranges of the 4225-RPM.

Disable outputs at completion

Select this option to disable the outputs when the test completes. Clear this option to leave the outputs enabled when the test completes.

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Current Spot Mean High

Makes current measurements on the amplitude. Available when the Test Mode is set to Pulse I-V. The following figure shows an example of a spot mean measurement on pulse high (amplitude) and

pulse low (base level). For a more detailed example, refer to Test Mode (PMU) (on page 3-16

Current Spot Mean Low

Makes current measurements on the base level. Available when the Test Mode is set to Pulse IV.

Figure 36: Spot mean measurements

The following figure shows an example of a spot mean measurement on pulse high (amplitude) and pulse low (base level). For a more detailed example, refer to Test Mode (PMU) (on page 3-16

Figure 37: Spot mean measurements

Measure Current Range (PMU)

The measure range determines the full-scale measurement span that is applied to the signal. Therefore, it affects both the accuracy of the measurements and the maximum signal that can be measured.

The current measure range affects the time required to obtain settled measurements. Lower current ranges require additional time to reach a settled signal level. If the pulse timing parameters are too short for one or more current measure ranges, some ranges will be unavailable.

As shown in the following table, available current measurement ranges for the PMU depend on the selected voltage source range. The 10 mA measure range for the 10 V source range has better accuracy than the 10 mA range for the 40 V source range.

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10 mA

100 μA

200 mA

10 mA

800 mA

100 nA

100 μA

1 µA

10 mA

10 µA

800 mA

100 µA

—

1 mA

—

10 mA

—

200 mA

—

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Fixed current measurement ranges (PMU only) 10 V range 40 V range

−

If you are using an RPM, additional current measurement ranges become available to the PMU. The following table lists the current measurement ranges for the PMU when using the RPM. The 10 mA measure range for the 10 V source range has better accuracy than the 10 mA range for the 40 V source range.

Current measurement ranges for the PMU with RPM 10 V range 40 V range

The current range options are:

• Auto: The instrument automatically optimizes the measurement range as the test progresses.

This option provides the be s t r es olution when the measurements span s ev era l de c ades . Howev er, time delays can occur with range changes that can limit the measurement speed.

• Limited Auto: A compromise between Auto and a fixed range option. It allows you to specify the

minimum range that the PMU uses when it automatically optimizes the current measurements. This option reduces test time when you do not need maximum resolution at minimum currents. The available ranges are limited by the chosen pulse timing parameters. For additional information, see PMU minimum settling times versus current measure range.

• Specific ranges: You can select a fixed measurement range.

The available ranges are limited by the pulse timing parameters. For additional information, see

minimum settling times versus current measure range (on page 3-24).

PMU

Low Range

Available when the Measure Range is set to Limited Auto. This sets the minimum range that the instrument uses.

Current Sample Waveform

Makes current measurements on the waveform. Available when the Test Mode is set to Waveform Capture.

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Voltage Spot Mean High

Makes voltage measurements on the amplitude. Available when the Test Mode is set to Pulse IV. The following figure shows an example of a spot mean measurement on pulse high (amplitude) and

pulse low (base level). For a more detailed example, refer to Test Mode (PMU) (on page 3-16

Voltage Spot Mean Low

Makes voltage measurements on the base level. Available when the Test Mode is set to Pulse IV. The following figure shows an example of a spot mean measurement on pulse high (amplitude) and

pulse low (base level). For a more detailed example, refer to Test Mode (PMU) (on page 3-16

Figure 38: Spot mean measurements

Figure 39: Spot mean measurements

Voltage Sample Waveform

Makes voltage measurements on the waveform. Available when the Test Mode is set to Waveform Capture.

Report Timestamps

Available when the Test Mode is set to Waveform Capture. When Report Timestamps is enabled, each measurement includes a timestamp and the waveform is graphed (voltage/current versus time) in the Analyze graph.

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Report Status (PMU)

When this option is sel ec te d, Clarius records me asur e ment s tat us i nformation when the tes t ex ec ut es . A column of the Analyze spreadsheet displays this information. Hover over a cell to review the information. An example of the status information is displayed in the following figure.

For PMU measurements, this information is also available as a 32-bit word. The status code bit map is listed in the LPT pulse_fetch command description.

Figure 40: Report Status for PMU in the Analyze sheet

PMU measurement status

ITMs can provide status information for the 4225-PMU measurements in the Analyze sheet Run tab. The column for the status codes is labeled PMUx_y_S, where x is the PMU instrument number (PMU1, PMU2, and so on), and y is channel number (channel 1 or 2). The PMU status code indicates pulse measurement status, source and measure ranges, whether an RPM is connected, and load-line effect compensation (LLEC) status, and flags any faults (errors).

If a pulse measurement fault occurs, the data values in the entire row are displayed in a different color. A single measurement may have more than one condition. Hover over a cell to review the status information.

The data values identify the fault type as follows:

• Red = Source in compliance

• Magenta = Measurement overflow

• Orange = LLEC failed

• Blue = Current, voltage, or power threshold reached

An example of the Analyze sheet when a measurement overflow occurred is shown in the following figure. The figure also shows an example of the message that is displayed when you place the cursor on a flagged PMU1_1_S cell.

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Figure 41: Status tab showing faults

Status codes

Each measurement includes an 8-digit status code. Assign the following letters to the code and use the following table to determine status:

A B C D E F G H In the figure shown in PMU measurement status (on page 3-12 A. 1 = LLEC failed, sweep not skipped (yellow indicates that LLEC failed)

B. 1 = RPM being used C. 0 = Not applicable (always 0) D. 1 = Spot mean measurement type E. 0 = Source not in compliance, no threshold reached F. 0 = No measurement overflows G. 2 = 10 μA measure range H. 1 = Channel 1, 10 V measure range

), the circled status code is 11010021:

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0 = LLEC disabled, sweep not skipped

1 = LLEC failed, sweep not skipped

3 = LLEC successful, sweep not skipped

4 = LLEC disabled, sweep skipped

5 = LLEC failed, sweep skipped

7 = LLEC successful, sweep skipped

RPM mode settings

0 = No RPM

1 = RPM

2 = Bypass; PMU

3 = Bypass; SMU

4 = Bypass; CVU

Reserved for future use

Always 0

Measurement type 1 = Spot mean

2 = Waveform

Current threshold, voltage threshold, power

0 = None

1 = Source compliance

2 = Current threshold reached or surpassed

4 = Voltage threshold reached or surpassed

8 = Power threshold reached or surpassed

Voltage measure overflow and current

0 = No overflow

1 = Negative voltage overflow

2 = Positive voltage overflow

4 = Negative current overflow

5 = Negative voltage and negative current overflow

6 = Positive voltage and negative current overflow

8 = Positive current overflow

9 = Negative voltage and positive current overflow

A = Positive voltage and positive current overflow

Current measure range

0 = 100 nA (RPM only)

1 = 1 μA (RPM only)

2 = 10 μA (RPM only)

3 = 100 μA

4 = 1 mA (RPM only)

5 = 10 mA

6 = 200 mA

7 = 800 mA

Channel number and voltage

1 = Ch1, 10 V

2 = Ch2, 10 V

5 = Ch1, 40 V

6 = Ch2, 40 V

3: Setting up PMUs and PGUs in Clarius Model 4200A-SCS Pulse Card (PGU and PMU)

PMU measurement status codes Code

Summary or description Value

letter

A Load-line effect compensation (LLEC ) and

sweep

threshold, and source compliance

measure overflow

measure range

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Compensation Short Connection

Use to enable or disable short connection compensation. Refer to PMU connection compensation (on page 2-20) for detail on setting up and using connection compensation.

Load Line Effect Compensation

Use to enable or disable load-line effect compensation (LLEC). Refer to Load-line effect

compensation (LLEC) for the PMU (on page 2-24) for detail on setting up and using load-line

effect compensation.

DUT Resistance (R DUT)

The DUT resistance value. Refer to DUT resistance determines pulse voltage across DUT (on page 4-17) for detail on calculating DUT resistance.

Max Voltage Estimator

The Maximum Voltage Estimator is a tool that enables you to calculate the maximum voltage and current based on the selected voltage range and the DUT resistance value you type in. The estimator does not affect the pulse output.

For a more accurate maximum voltage estimate, add the interconnect resistance to the DUT resistance value. The typical resistance of a white SMA cable is 0.75 Ω and the typical prober pin-to-pad resistance is 1 Ω to 3 Ω. Poor pin-to-pad contacts could be in the range of 10 Ω to 15 Ω.

The V Max and I Max values are valid with LLEC enabled or disabled. It is the maximum output of the PMU. The LLEC does not change the maximum output voltage or current of the PMU.

Threshold Current

The current threshold allows you to set a threshold. If the threshold is reached or exceeded, the present sweep is stopped. Testing continues with any subsequent sweeps.

This threshold is a comparison of the measurement after the pulse has been applied to the DUT (the threshold value will be exceeded, at least slightly). The degree to which the signal exceeds the threshold before the threshold is triggered is a function of the DUT response and test configuration. Generally, smaller voltage step sizes will reduce the amount that the signal exceeds the threshold. You can specify more than one threshold for each channel.

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Threshold Voltage

The voltage threshold allows you to set a voltage threshold. If the threshold is reached or exceeded, the present sweep is stopped. Testing continues with any subsequent sweeps.

Threshold Power

The power threshold allows you to set a power threshold. If the threshold is reached or exceeded, the present sweep is stopped. Testing continues with any subsequent sweeps.

On the 40 V range, you may see the error message, "Pulse waveform configuration exceeded output power limits." To solve this issue, try increasing the period or using the 10 V range.

PMU Test Settings

The settings that are available for PMU tests are described in the following topics.

Pulse Settings

Under Pulse Settings, you can select the type of pulse test, how measured pulse values are handled, and the number of pulses.

Test Mode (PMU)

The Test Mode selects the type of pulse test. You can select:

• Pulse IV: This test mode performs spot mean measurements (V or I) of the amplitude or base

portions of one or more pulses. Typically, current versus voltage is graphed in the Analyze graph. The pmu-iv-sweep project provides an example of a pulse drain family of curves using the pulse test mode.

• Waveform Capture: This test mode samples the entire waveform. The waveform is graphed

(voltage and/or current versus time) in the Analyze graph. The pmu-1ch-wfm project provides an example of a waveform c apture. N ote th at the T iming Swee p Step o ption ( in the Advance d di alog) is disabled when Waveform Capture is selected.

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For pulse I-V, spot mean measurements are made on pulse amplitude and base level. You can measure voltage and current. The following figure shows the measure windows for spot mean measurements. The start measure and stop measure points for ITMs are fixed at 75 percent and 90 percent for both amplitude and base level.

Figure 42: Pulse I-V (spot mean measurements)

The number of measurement samples that are made is relative to the widths of the magnitude and base level. For example, if the width of the magnitude is 1 μs, the measure window is 750 ns to 900 ns. If the width of the base level is 2 μs, the measure window is 1500 ns to 1800 ns.

For waveform capture, measurement samples are acquired on pulse rise, pulse amplitude, pulse fall, and a small portion before the rise (pre-data) and after the fall (post-data) on the base level, as shown in the following figure.

Figure 43: Waveform capture

For detail on spot mean measurements, refer to Spot mean measurements (on page 4-26). For user test module (UTM) programming, refer to the pulse_meas_sm function.

For detail on waveform measurements, refer to Waveform measurements (on page 4-27). For UTM programming, the pulse_meas_wfm function is used to configure waveform measurements.

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For UTMs, the pulse_meas_timing function allows you to adjust the measure window for the pulse I-V test mode or the pre-data and post-data settings for the waveform measurements. For ITMs, the measure window and pre-data and post-data settings are fixed.

Function descriptions are provided in Model 4200A-SCS LPT Library Programming.

Measure Mode

For Measure Mode, you can select Average Pulses or Discrete Pulses. When Average Pulses is selected for Pulse IV, the measured values of two or more pulses are

averaged. See the Pulse IV (Average pulses) measurement example (on page 3-18 Capture, select Average Pulses to average each sample in the waveform with the same point in subsequent waveforms, for each pulse specified by the number of pulses.

When Discrete Pulses is selected for Pulse IV, the measured value of each pulse is acquired. Refer to the Pulse IV (Discrete pulses) measurement example (on page 3-18 sample for every waveform is recorded in the Analyze sheet. Refer to the Waveform Capture

(Discrete Pulses) measurement example (on page 3-19).

). For Waveform

). For Waveform Capture, each

Pulse I-V (Average pulses) measurement example

For the example shown in the following figure, the mean of three pulses is averaged into a single reading (also called a spot mean). One averaged reading is yielded for each pulse. The result of the three averaged readings is placed in the Analyze sheet.

Figure 44: Pulse IV - Average pulses

Pulse I-V (Discrete pulses) measurement example

For the example shown in the following figure, the readings are the result of a pulsed IV sweep from 2 V to 5 V (in 1 V steps) with the discrete number of pulses set to three. This test yields the spot mean of the three pulses for each step of the sweep. The Analyze sheet for the 12 readings are also included in the following figure.

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Figure 45: Pulse IV - Discrete pulses

Waveform Capture (Discrete Pulses) measurement example

For the example shown in the following figure, the samples of three pulses are captured. The 51 samples (17 samples x 3 pulses) are placed in the Analyze sheet.

Figure 46: Waveform capture - Discrete pulses

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Number of Pulses

The number of pulses for the PMU channel to output and measure for each step in the sweep (1 to 10,000). If you enabled autorange, load-line effect compensation (LLEC), or thresholds, the number of pulses is output multiple times for each step in a sweep.

Sweep Master

If there are multiple steps or sweeps in a test, use this to designate which instrument is the master. Refer to Step or sweep multiple device terminals in the same test (on page 3-39) for detail.

Timing Parameters

The following figure shows parameter stepping and sweeping examples. In these examples, the Number of Pulses parameter is set to 3, so there are three pulses per period.

Figure 47: Parameter stepping swee ping examples

• Period: The pulse period steps or sweeps from a short period to a long period (or from a long

period to a short period).

• PW: The pulse width (PW) steps or sweeps from a short pulse width to a long pulse width (or

from a long width to a short width).

• Rise: The pulse rise time steps or sweeps from a long rise time to a short rise time (or from a

long rise time to a short rise time).

• Fall: The pulse fall time steps or sweeps from a long fall time to a short fall time (or from a long

fall time to a short fall time).

In the figure above, the ellipsis (...) between each burst of pulses indicates additional time that the pulse channel is outputting 0 V dc (the pulse channel is not pulsing). This time allows for analog-to-digital (A/D) sample processing and, if enabled, measure ranging and LLEC. For more information on LLEC, see How LLEC adjusts pulse output to the target levels (on page 2-25

For the 40 V range for the 4220-PGU and 4225-PMU in pulse mode, the pulse generator is limited to slew no more than 160 MV/s when pulsing more than 10 s.

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Period

The pulse period is the time interval between the start of the rising transition edge of consecutive output pulses, as shown in the following figure. To minimize self-heating effects, set a pulse period that is 10 to 100 times longer than the pulse width to produce a duty cycle that is 1 percent to 10 percent.

Figure 48: Pulse period

Width

The pulse width is the interval between the rising-edge and falling-edge medians. For a pulse with fast edges (a short transition time), the pulse width is essentially equal to the interval from the start of the rising edge to the start of the falling edge.

Rise and fall times are set independently. The pulse width is not affected by a change to the transition time. However, start points may shift with changes in transition time.

The dashed line pulse in the following figure shows how increased transition time can affect the rising edge and falling edge of the pulse. The shaded areas of the pulse show the changes in the slopes. Notice that the pulse width interval is not affected. If the transition time is increased, the pulse would not reach its programmed amplitude (100%).

Figure 49: Pulse width

Rise Time

The rise transition time for the pulse output.

Fall Time

The fall transition time for the pulse output.

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Pulse Delay

The pulse delay is the time interval between the start of the rising pulse edge of the trigger output pulse and the output pulse. You can set the rising or falling polarity of the trigger output pulse edge to the output pulse. The pulse delay has a variable delay with respect to the trigger output.

Figure 50: Pulse delay

Formulator

Opens the Formulator. The Formulator allows you to make data calculations on test data and on the results of other Formulator calculations.

Refer to “The Formulator” in the Model 4200A-SCS Clarius User's Manual for detail on using the Formulator.

Output Values

If you are using subsites, each time a subsite is cycled, the measurements for the selected Output Values are placed in the Analyze sheet for the subsite. For example, if the subsite is cycled five times, there will be five measured readings (Output Values) for the test. For details, see “Subsite cycling” in the Model 4200A-SCS Clarius User's Manual.

PMU Advanced Test Settings

To access these settings, on the Test Settings tab, select Advanced. The Pulse Settings and Timing Parameters are described in the PMU Test Settings (on page 3-16 The Timing Sweep determines which timing parameters control the step or sweep. You can only step

the timing parameters if the Operation Mode is set to pulse sweep or pulse train and if the Test Mode is set to Pulse IV. You can only sweep the timing parameters if the Operation Mode is set to pulse step or pulse train.

The Timing Sweep Step option is disabled when Waveform Capture is selected.

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Settling Times

The settling time is the time that it takes for pulse levels to stabilize after the voltage or current is changed, such as during execution of a sweep.

The Typical Minimum Timing Recommendations dialog displays typical minimum timing versus current measure range recommendations. These are the recommended minimums for each current measure range. Longer times may be required to accommodate DUT and interconnect settling.

Figure 51: Typical minimum timing recommendations

When using autorange with an RPM connected, use the timing values on the top row (or longer/slower values). If using limited autorange, start with the timing values for that range.

If pulse width or period timing parameters are too narrow for a chosen measure range, a message is displayed showing the change to the current measure range for each effected channel. To avoid these changes, follow the guidelines shown in the previous figure. See

PMU minimum settling times

versus current measure range (on page 3-24) for more information.

Settling time includes the following τ (tau) time constants:

• τInstrument: Varies mainly with current range.

• τSystem: Due to cables, switches, and probers.

• τDUT (Device Under Test): Due to the implicit characteristics of the DUT.

• τDielectric Absorption: An issue only on the low current ranges.

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Settling time is measured from the 90 percent point on the rising edge to the point where the pulse level remains in the accuracy band, as shown in the following figure.

Figure 52: Settling time

PMU minimum se ttling times versus current measure range

The PMU and RPM current measure ranges require time to reach a settled value. The amount of settling time that is required increases for the lower current measure ranges.

You can set the pulse timing parameters (pulse width, rise, and fall) to any valid values and are independent from the recommended minimum timing values required to obtain settled readings. If the chosen pulse width is too narrow, the lower current measure ranges are not available. The timing of the pulse top and pulse base are used, along with the minimum timing in the chart to determine which current measure ranges are available.

In ITMs, when you modify the PMU timing settings in the Advanced Test Settings, if you make a pulse timing change that affects the measure range of a PMU channel, a message noting the unavailable ranges is displayed. You should check the recommended pulse width and period for the measure ranges noted in the message. When setting the PMU force measure options, if a timing parameter prevents use of one or more PMU or RPM measure ranges, the note in the center of the window turns red and lists the unavailable ranges. Access the PMU force measure options by selecting the FORCE MEASURE button.

The Typical Minimum Timing Recommendations dialog shows the recommended minimum pulse widths and transition (rise and fall) times for each current measurement range. These times are the minimum time necessary for the PMU, or PMU with RPM, to reach a settled value (into an open). Additional time must be entered to account for DUT settling time, usually due to RC effects.

If you need to use autoranging with the RPM, note that the appropriate minimum timing values are the first row in the table. Note that the pulse timing values are not altered during the test, unless a time sweep or time step is configured. This means that the pulse width is not changed as the measure range changes. When using autoranging or limited autoranging, choose the recommended minimum timing values for the lowest chosen measure range.

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You can override the settled measurement requirement for the PMU or PMU+RPM measurements. In the Clarius My Settings, Environment Settings, select PMU: Allow unsettled measurements.

The following figure contains a graph of the current signal settling time of three current measure ranges of the 4225-RPM. The graph shows the settling time of a 1 V amplitude pulse in to an open (high impedance) with a 300 ms pulse width and a 1 ms transition time. Note that this figure does not show the voltage signal.

Figure 53: 4225-RPM current signal settling time

PMU pulse timing preview

Before executing an ITM test, you can preview a waveform generated using the settings. This can help you understand the behaviors of the test settings without applying signals to the test device. The Pulse Timing Preview is in the PMU Advanced Test Settings dialog.

To open the PMU Advanced Test Settings dialog, select Test Settings, then Advanced (see following figure).

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Figure 54: Timing button (PDU Definition tab)

An example is shown in the following figure.

Figure 55: Pulse Timing Preview example

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The preview displays representations of the waveforms for the different PMU channels in the test. The illustrated pulse waveforms are defined by the Pulse Timing settings for the specific PMU. This preview provides a representation of parameter values (no signals are output to the test device). It is not intended to be a strict definition of the actual number of pulses or pulse voltages to be applied to the device under test (DUT). When the actual test is running, the actual number of pulses or pulse voltages may be different than the preview.

Enabling current measure ranging or load-line effect compensation (LLEC) requires pulses that are in addition to what is shown in the preview. To learn how the PMU handles device under test (DUT) load variation and measure ranging during a test, refer to

levels (on page 2-25).

Review the following examples to understand the Pulse Timing Preview feature.

PMU amplitude sweep example (one-channel)

This figure illustrates the advanced terminal settings for a pulse amplitude sweep using a single PMU channel.

Figure 56: One-channel PMU amplitude sweep

How LLEC adjusts pulse output to the target

The following figure illustrates the Advanced Test Settings for a six-step pulse amplitude sweep. In this sweep, the PMU Advanced Terminal Settings dialog (see previous figure) defines the test parameters.

In the Pulse Timing Preview, there are two graphs. The bottom graph, labeled “Entire Test,” shows the complete test. This graph shows each sweep and step point for the entire test. The graphed points reflect the PMU Advanced Settings for the PMU channel in the test. The cursor (the pair of vertical black lines on the Entire Test graph) defines the content of the upper graph labeled “Expanded View”). The test settings shown in the previous figure define the six sweep points that are

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shown in the bottom graph of the following figure as six pulse periods. In this example, the pulse periods have voltage amplitude increasing from 0 V to 5 V.

The graph labeled “Expanded View” provides in-depth information on the section designated by the cursor lines on the Entire Test graph. The graphed points reflect the timing parameters (Pulse Timing Preview) and settings from the PMU Advanced Settings dialog for each PMU channel in the test, but only for the area specified by the cursor.

Figure 57: Six-point pulse amplitude sweep

Select Preview Test to animate the waveform. The cursor moves from left to right on the bottom graph while displaying the point waveform of each sweep within the cursor on the top graph.

Selecting Preview Test does not output any pulses, but it does illustrate how the test will progress as a result of the test parameter settings.

PMU amplitude sweep and step example (two-channel)

In this two-channel example, one channel is sweeping while the other channel is stepping. The sweeping channel is performing pulse amplitude sweeps with nine sweep points. On each inner loop,

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Operation modes

Pulse Amplitude Step

Pulse Am plitude Sweep

Start Voltage

1 0 Stop Voltage

2.5

Step Voltage

0.5

Number of steps or sweep points

4 (automatically calculated)

9 (automatically calculated)

-SCS Pulse Card (PGU and PM U) User's Manual Section 3:

PMU1-2 sweeps 0 V through 4 V in 0.5 V increments. The stepping channel is performing pulse amplitude steps with four step points. On the outer loop, PMU1-1 pulses the four steps of 1 V through

2.5 V in 0.5 V increments.

Terminal Settings for the following figure PMU1-1 (blue waveform) PMU1-2 (light blue waveform)

To preview the test, select the Test Settings tab, then select Advanced. Under Pulse Timing Preview, you can preview a single channel or all channels in the test. The following figure has Show All selected, which graphs all channels in the test. The Entire Test graph shows four steps of nine points each. The sweep and step count displays the position of the cursor in the overall test. This example has the number of pulses set to one.

Figure 58: PMU Timing Preview, two channels

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If you change the number of pulses to three (instead of one) and only display one channel (PMU1-1, instead of Show All), the preview of the waveform changes as shown in the following figure. Each point in the step now uses three periods, so there are three pulses shown in the Expanded View. In the Expanded View, the x-axis shows the time in seconds. This is three times longer than the Expanded View graph when number of pulses is set to one that was shown in the previous figure.

Figure 59: Two-channel test (stepping and sweeping) with three points (only PMU1-1

displayed)

If you configure the preview to all channels, both the sweeper and stepper are displayed for the three-pulse test, as shown in the following figure.

The Number of Pulses parameter determines the number of pulses that are output and measured for each attempted point in the sweep or step. The PMU amplitude sweep and step example (two-channel) test figure shows PMU1-1 (the stepper) with the number of pulses changed to three. Notice that each sweep point of the displayed waveform in the figure has three pulses (number of pulses set to three). The light blue waveform in the figure has one pulse (number of pulses set to one). Because the cursor in the lower graph always contains the complete waveform of each point in a test, the top graph shows the three pulses. The following figure shows both channels for the sweep and

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step test with the number of pulses set to three. Note that the value for the number of pulses does not affect the number of sweep or step points in the test.

Figure 60: Two-channel test with three points (PMU1-1 and PMU1-2 displayed)

Higher channel count test example

This example shows how to use the Pulse Timing Preview for higher channel count tests.

Expanded View zoom

On the Expanded View graph, drag the cursor to define the area to magnify (the cursor changes to a magnifying glass). Note that each channel has a unique color and line width. When the channels overlap, narrower lines are shown on top of the wider lines. To return to normal magnification, double-click the graph or select Refresh. Multiple levels of zoom are supported, with a double-click returning each level. Note that the Refresh option restores the magnification that shows the Entire Test waveform.

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1.5 0 1.5

0.5 3 4 *

0.5 1 *

4 5 *

* Not applicable. The pulse voltage trains are fixed pulse voltage levels; they do not vary during the sweep or step points.

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The following figure uses the key test parameters shown in the following table.

Operation mode and voltages for the four channels

PMU1-1 PMU1-2 PMU2-1 PMU2-2

Operation mode Start or base

voltage Stop voltage Step voltage Number of points

Pulse amplitude step

Pulse amplitude sweep Pulse voltage train Pulse voltage train

Figure 61: Four-channel sweep and step (2 pulse trains)

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Figure 62: Zooming (Expanded View graph)

Scrolling the magnified area

To move the viewable area of the graph after you zoom in on a graph, hold down Shift while dragging the mouse.

Entire Test zoom

You can use zoom on the Entire Test waveform graph. It works like zoom in the Expanded View. After you zoom in, you can also move the viewable area of the graph using Shift+click. See the following figure for a view of moving the lower graph using the mouse pointer. Note the gaps between the pulse waveforms shown in the Expanded View zoom (on page 3-31

) figure; gaps also exist in the following figure. These gaps indicate the time between sweep points where the PMU performs calculations for the test while the pulse channels output 0 V. To learn more about how these gaps relate to how the PMU handles DUT load variation and measure ranging during a test, see How LLEC adjusts pulse

output to the target levels (on page 2-25).

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Select Shift+click and move or scroll a magnified graph by moving the mouse.

Figure 63: Scroll (or move) a magnified entire test graph

Errors

If either graph is not updating as expected, select Refresh to zoom out and redraw both graphs. It is possible to have a test with too many pulses to be suitably graphed. This may be from too many pulses from a large number of sweep points or step points, or a large number of pulses. The following figure shows the output “Too many pulses to graph” for the lower graph. This does not mean that the test will not run. If you select OK on the PMU Advanced Test Settings dialog and it does not generate any warning or error messages, the test is valid and runs (even though the entire test waveform cannot be displayed).

Figure 64: Preview error (Too many pulses to graph)

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PMU capacitive ch arging/discharg ing effects

During pulse transitions, the measured current charges and discharges the capacitance in the system (see following figure, red waveform). This system capacitance consists of the cable capacitance, PMU (with RPM, if connected) capacitance, and device capacitance. The following figure shows the pulse waveform showing capacitive charging and discharging current waveform in relation to the applied voltage waveform of the PMU connected to the supplied 2 m (6.5 ft) SMA cable (no DUT connected).

Figure 65: Capacitive charging and discharging

The setup used to generate these waveforms is shown in the previous figure, and also shows the capacitance and the charging effect (red arrows) seen during pulse transitions. This setup shows a single channel of a PMU, with the supplied 2 m (6.5 ft) white SMA cable connected to the channel output. Note that the other end of the SMA cable is open (no connection).

The current shown in the previous figure is measured by the PMU, but is not flowing through a device under test (DUT). The measured current is the sum of this charging or discharging current, as well as the current flowing through the DUT. This current is primarily caused by the capacitance in the cable and is described by the following equation:

I = C * dV/dt Where:

• I is the measured current

• C is the capacitance

• dV/dt is the pulse voltage amplitude divided by the rise (or fall) time

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The equation shows that this effect is a function of the capacitance, as well as the dV/dt. Therefore, minimizing the capacitance will reduce this measurement artifact. The cabling is typically the largest contributor to the system capacitance. Slowing down the pulse transitions will also reduce the height of the current charging effect.

This capacitive charging current is primarily a measurement artifact, as the current does not flow through the DUT. Note that if a spot mean is taken during the settled portion of the pulse, then this charging does affect the spot mean measurement.

The following two figures show the waveforms and setup for a pulse test on a resistor DUT and illustrates a configuration to eliminate this artifact. The following figure shows that the channel 2 current waveform does not have this current charging artifact. This is because channel 2 is not pulsing, so dV/dt = 0. Using channel 2 in this configuration is sometimes called "low-side measurement." This measurement approach is useful when analysis of the current signal pulse transitions is required.

Figure 66: Low-side measurement waveforms

The previous figure shows the current waveforms for both PMU channel 1 (high side) and channel 2 (low side) current measurements. Note that channel 2 does not show the capacitive charging effects. Also, note that the channel 2 current measurement is negative because the current is flowing into channel 2.

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Figure 67: Setup for low-side measurement

In the previous figure, the voltage pulse is applied by channel 1; channel 2 does not pulse. Therefore, there is no dV/dt, and therefore there are no charging or discharging currents during the pulse transition. The red arrows show charging and DUT current for channel 1. The green arrow illustrates the DUT current only for channel 2.

PMU and RPM measur e ranges are not sou r ce ranges

Unlike a source-measure unit (SMU), the PMU and RPM current measure ranges are measure ranges only, not source and measure ranges. For example, the SMU 10 mA measure range has a maximum source and measure value of ±10.5 mA, including the five percent overrange. The 10 mA measure range of the PMU 10 V range has a maximum measurement of about ±10 mA, but the full source capability of the 10 V source, which is ±200 mA. An alternate way to present this difference is that the SMU range has a source compliance equal to the measurement limit, but the PMU and RPM ranges have a source compliance larger than the measure range. Note that for the maximum PMU current measure ranges (200 mA for the 10 V range, 800 mA for the 40 V range), the source limit is the same as the measure limit, so the 200 mA and 800 mA ranges act similar to the SMU current range.

This measure-only limit is necessary for the best performance of the pulse when using the PMU alone or with the RPM. Generally, the purpose of a pulse measurement is to minimize the time required to make a measurement in order to minimize device self-heating or some other time-based device behavior.

To minimize the measurement time, the signal at the device under test (DUT) must get to the specified voltage level and settle as quickly as possible. A key aspect of this goal is handling the capacitive charging effects during the pulse transitions.

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Since the interconnect and the DUT always have some capacitance, it is best to charge up this capacitance as quickly as possible. This can be done by allowing the maximum amount of current to flow into the capacitor during charging. This may cause an overflow for the measure range during transitions, especially on the lower RPM measure ranges. Note that the measurement range cannot be changed within a pulse, so a single measure range must be used for the entire pulse.

If the PMU or RPM was current limited to the measure range, the charging rate would require a longer time to reach a settled signal. With the maximum current available at all measure ranges, the signal will settle as fast as possible, allowing for a good dc-like current measurement using the shortest possible pulse. This is especially important at the lower current measure ranges, when the settled part of the pulse may have a signal level in the nA (or single μA) value, but the charging current is possibly tens of μA (or mA, respectively).

See PMU capacitive charging/discharging effects (on page 3-35 capacitive charging effect and how to work around it.

) for information on the cause of the

4220-PGU and 4225-PMU outp u t limitations

In addition to the maximum output of the PMU and PGU instrument cards (see DUT resistance

determines pulse voltage across DUT (on page 4-17)), the pulse instrument cards also have a limit for

the number of large amplitude pulse transitions within a period. The 4200A-SCS system enforces limits on the quantity and amplitude of waveforms that the 4220-PGU and 4225-PMU may generate. A test exceeding these internal limits generates error code -830. To fix this problem, increase the pulse period, decrease the voltage amplitude, or both. For information on the pulse default values, see the pulse_init LPT command description.

Configure the PGU, PMU, and RPM using tests

An ITM automatically controls the RPM based on the type of test (pulse, CV, SMU). RPM switching can only be controlled using the rpm_config LPT function in a UTM. For details, refer to

RPM as a switch (on pag e 2-9).

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Step or sweep mul tiple device terminals in the same test

Multiple steps or sweeps in an interactive test module (ITM) must track with regard to step number and duration. For example, you might want to apply multiple steps to multiple device terminals, such as when stepping the biases on two transistor terminals and sweeping voltage or current on the third terminal. In this setup, Clarius automatically sets the step operations to occur simultaneously, with one terminal set up as the master. All other step functions are automatically designated as subordinates. The following figure illustrates this concept.

Figure 68: Master step versus subordinate step

In the following figure, the step width and the number of steps of the subordinate track the step width and number of steps of the master sweep.

Figure 69: Master and subordinate sweeps

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In the following figure, the step width and number of steps of the subordinate list sweep tracks the step width and the number of steps of the master list sweep.

Figure 70: Master list sweeps versus subordinate list sweeps

If you do not specify an instrument to be the master, the first instrument that was assigned to the step or sweep operation mode is assigned to be the master. You can change this designation in the Test Settings pane.

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When a master is set, Clarius sets the points and step size values for the subordinate terminal to be the same as the settings for the master terminal. You cannot change the subordinate points value for the subordinate terminal. For list sweeps, the number of points in the list items for the subordinate is changed to match the number of points in the master. If points are added to the master, the last point of the subordinate list is repeated. If points are removed from the master, the same number of points are removed from the end of the subordinate list.

You can have a dual sweep on a subordinate terminal even if the master is not set to dual sweep. In this case, the dual sweep of the subordinate terminal has a total number of steps equal to the number of steps in the master terminal. For example, if the master terminal is set to measure ten points, the subordinate dual sweep will measure five points on the first side of the sweep and five points on the second side of the dual sweep. If the master is set to an odd number of points, the subordinate terminal will repeat the measurement of the last sweep point.

The subordinate SMUs are not automatically set for dual sweep when Dual Sweep is enabled for the master SMU. Dual Sweep must be individually enabled for each SMU.

To specify the master sweep:

1. Select the test.

2. In the right pane, select Test Settings.

3. For Sweep Master, select the instrument that you want to designate as the master.

Basic troubleshooting procedure

If the test pulse I-V results do not meet expectations, use the following steps as a guide for troubleshooting. Because the pulse I-V results extract the spot mean measurements from the top of the pulse, good pulse I-V results require a reasonable pulse shape.

Step 1. Verify prober connections from the PMU or RPM to

the DUT

1. Use cabling and connections optimized for high frequency (>150 MHz).

2. Connect the low side of the device under test (DUT) to the shield of the coaxial cable (see

connections (on page 2-2)), or connect the low side to another PMU or RPM channel (see Connections to prober or test fixture bulkhead connectors (on page 2-16) or Pulse I-V (Average pulses) measurement example (on page 3-18)).

3. Connect the shields (refer to the figure in Local sensing (on page 2-17) that shows four-terminal

local sense connections).

Shield

4. If you are not using the supplied cabling, minimize the loop area created by the shield and center

conductor. Do not use the G NDU connection for the retur n or ground path for an y puls e I -V signal. Refer to Shield connections (on page 2-2

5. Minimize the cable length. See Cable length (on page 2-3).

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Step 2. Verify the pulse shape

To check that the pulse shape provides a flat, settled portion near the end of the pulse top:

1. Configure the test for Waveform Capture.

2. Ensure that voltage, current, and time waveforms are measured. See

Waveform capture

measurement configuration (on page 3-11).

3. Enable the status for each PMU channel in the test. See PMU - all terminal parameters (on page

3-6).

4. Select a voltage level for each channel that puts the device into the area of the curve that is

questionable. If a large portion of the pulse I-V curve is under question, viewing the waveform shape at two or three different voltage levels may be necessary.

5. Configure the ranges to match the pulse I-V test.

6. Configure the connection and load-line effect compensation (LLEC). To match the pulse I-V test

conditions, enabling LLEC allows the PMU to compensate for lower voltage levels at the test device when current is flowing. See Enable LLEC (on page 2-29

7. Configure the graph with the time value on the x-axis, all voltage measurements on Y1, and

current measurements on Y2. On the graph, select Graph Settings and select Define Graph to open the Graph Definition dialog. By default, the voltage waveforms are blue and use the left (Y1) axis; the current waveforms are red and use the right (Y2) axis.

8. Save the project.

9. Run the test and view the waveform on the graph. While viewing the graph, check that the

voltage has a fairly flat top, without significant ringing or oscillations.

There may be current peaks during the pulse transitions. The peaks during the transitions are expected; see PMU capacitive charging/discharging effects (on page 3-35

). The current waveform may show settling, but should not have significant ringing. An example of a good waveform shape is shown in

PMU and RPM measure ranges are not source ranges (on page 3-37).

Due to interconnect and DUT settling time requirements, low current measurements (< ~10 mA) may require a wider pulse than the recommended minimum timing values. This is especially important for <1 mA level current measurements using the 4225-RPM. See

PMU minimum

settling times versus current measure range (on page 3-24)

A waveform graph may show a Measurement Overflow condition. This overflow during the pulse transitions does not affect the spot mean measurements, because the

spot mean is taken during the settled portion of the pulse top. Note that this error would not occur during pulse I-V, because the spot mean measurement window does not incl ude t he risi ng or falli ng edges of the pulse. Refer to Test Mode (PMU) (on page 3-16),

PMU and RPM measure ranges are

not source ranges (on page 3-37), and Measure Mode (on page 3-18) for more information.

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Step 3. Is the pulse level correct for each channel?

1. If the pulse level is not correct for each channel, enable load-line effect compensation (LLEC). To

compensate for the IR drop effect, the LLEC algorithm applies multiple pulses at each sweep step; make sure that the DUT behavior is not adversely affected by the LLEC approach.

2. Run the test again and compare results. If the results match the test settings, the issue was the

lack of LLEC.

The load-line effect can reduce the voltage level at the DUT terminal when current is flowing. See

Load-line effect compensation (LLEC) for the PMU (on page 2-24

Refer to Step 4. Is the pulse I-V curve suspect? (on page 3-43) for examples with LLEC disabled and enabled.

Step 4. Is the pulse I-V curve suspect?

If the waveform has a good shape (Step 2. Verify the pulse shape), and the pulse level is correct (Step 3. Is the pulse level correct for each channel?), but the pulse I-V curve is suspect, perform the steps below.

In this procedure, you set test parameters to provide boundaries for the test envelope. When load-line effect compensation (LLEC) is disabled, the source voltage must be bounded.

LLEC may not respond properly for a high-gain transistor (for example, a compound semiconductor-based amplifier or power transistor).

If the pulse I-V curve is suspect:

1. Disable the load line for the gate and drain in the Key Parameters. For an ITM, see

effect compensation (on page 2-24).

2. Choose the maximum voltage for the selected source range. For example, many high-power

transistors require fairly high voltages and currents, so the PMU 40 V source range is common.

3. Set the thresholds in the All Parameters pane (see following figure and

parameters (on page 3-6) for more detail). Enter the maximum voltage for the DUT. For a

transistor, set the ThresholdVoltDrain voltage for the maximum voltage for the drain.

PMU - all terminal

Load-line

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Figure 71: PMU IV sweep All Parameters thresholds

4. Enter the maximum power for the test device. An example of a transistor test with LLEC disabled with a power threshold of 3 W and a voltage

threshold of 12 V is shown in the following figure. Note that each threshold allows the test to be bounded. Also note that the thresholds do not stop the test at exactly the threshold value, but only after the threshold has been exceeded. One test point always exceeds the threshold. You can reduce the amount that the threshold is exceeded by using smaller sweep step sizes.

Figure 72: Vd-Id family of curves with LLEC disabled

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The following figure shows a family of curves from a fairly high-powered device with the load-line effect.

The following figure shows the same device tested with load-line effect compensation enabled. With LLEC enabled, the curves stop at the programmed V

= 12 V. Note that the top curve, in the red circle,

did not reach the 12 V setting. This is because the PMU 40 V source range reached source compliance. In this case, the PMU is at its limit and cannot source any more voltage or current to this particular resistance. See t he 4200A-SCS Parameter Analyzer Datasheet for more information on the PMU maximum source power versus device resistance. You can access the datasheet from the Learning Center.

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Figure 73: Vd-Id family of curves with LLEC enabled (every curve finishes at Vd = 12 V)

For user test modules (UTMs), although the process described above applies, there are a few differences. Although ITMs and UTMs can perform similar tests, UTMs are based on user modules. UTMs have a much wider range of test behaviors and possibilities than ITMs. This document provides a framework for troubleshooting UTMs (individual UTM issues are not covered).

In addition to the above procedure based on unexpected results, UTM troubleshooting also involves error messages or codes. Typically, the user modules are written for a specific test or requirement and have minimal error checking. This means that parameter values or combinations of parameter settings may cause an error, which is the primary feedback about the test status.

This error may be generated from within the user module, or by an LPT command. The following figure shows the user module description for PMU_IV_sweep_Example. This description is part of the user module and may contain a description of the test, hardware requirements, individual parameter descriptions, and error code listings. The error code listings are after the parameter descriptions, which are typically at the bottom of the description content (you will need to scroll down the Help pane).

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Figure 74: PMU IV sweep Help pane description

This user module allows for an optional SMU to dc bias a transistor bulk while performing a pulse I-V sweep with a 4225-PMU and optional 4225-RPM. However, due to system restrictions, this SMU must not be connected to the test device through the 4225-RPM (an error results).

This example test is configured to use SMU1. SMU1 is connected through RPM1 of the system.

1. Set the SMU_ID from NONE to SMU1.

2. Select Analyze and view the Messages area at the bottom of the screen for error messages. For

example, if you get a message indicating "forcev(): Cannot force when not connected," you can check the Return Values in the Help pane for more troubleshooting information (see following figure). Note that value -233 indicates, "Ensure that the specified SMU is not connected through or associated with an RPM. If all SMUs are associated with RPM modules, choose NONE to permit the test to run."

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Figure 75: PMU IV sweep Return Values

It may also be necessary to research further using additional error codes. Three-di git negat ive er ror codes are most likely LPT-command error codes. Refer to “LPT Library Status and Error codes“ in Model 4200A-SCS LPT Library Programming. One-digit, four-digit, or five-digit error numbers are most likely from the user module, so refer to the user module description for information about these type of errors.

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Measurement types ................................................................ 4-25

In this section:

Models 4220-PGU and 4225-PMU ........................................... 4-1

4200A-SCS power supply limitations ....................................... 4-5

Pulse source-measure concepts .............................................. 4-8

Models 4220-PGU and 4225-PMU

Section 4

Pulse card concepts

LPT functions that pertain to the PGU and PMU are documented in “LPT commands for PGUs and PMUs” in Model 4200A-SCS LPT Library Programming.

) for additional

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4: Pulse card concepts Model 4200A-SCS Pulse Card (PGU and PMU)

The simplified circuits of the 4220-PGU and 4225-PMU pulse generators are shown in the following figure.

Figure 76: Simplified circuits of the PGU and PMU

PMU block diagram

The following figure shows the block diagram of the PMU. Each channel has two dedicated A/D converters to simultaneously measure current and voltage. The PMU controller controls the two output channels and any RPMs connected to it. The solid-state relays (SSRs) are high-speed and are used to test flash memory. The mechanical output relays are low-leakage. The block diagram for the PGU is similar, except it does not have measure capability and does not have the RPM connectors.

Figure 77: 4225-PMU block diagram

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Spot mean discrete

Samples a portion of the high and low levels. The samples are averaged to yield a mean measurements example figure; Measurement types (on page 4-25)).

Spot mean average

A specified number of pulse periods are output for the burst sequence. Spot mean single voltage and current reading for the high and low leve l s.

The entire pulse is sampled. Sampling is performed on the rise time, top width, and

measurements and Waveform measurements (with pre-data and post-data) figures).

Waveform average

A specific number of pulses are output for the burst sequence. Waveform discrete

burst sequence.

-SCS Pulse Card (PGU and PMU) User's Manual Section 4:

Pulse modes

The PGU and PMU support the following pulse modes:

• Standard pulse mode: For this two-level pulse mode, the user defines a high and low level for

the pulse output. The test modes for standard pulse are pulse I-V and waveform capture. See

PMU Test Settings (on pag e 3-16

• Segment Arb

that consists of three or more line segments. Segment Arb pulse mode for the PGU and PMU includes sequencing an d seque nce loop ing (see seg_arb_sequence and seg_arb_waveform. Also see Segment Arb waveform (on page 4-11

• Full-arb pulse mode: For this multilevel pulse mode, the waveform consists of a number of

user-defined points (s ee arb_array and arb_file). Also see Full Ar b wav e form (on page 4-15

for details on parameters. KPulse supports all of these pulse modes. Descriptions of the LPT functions are provided in Model 4200A-SCS LPT Library Programm ing.

) for the standard (two-level) pulse mode.

waveform: For this multi-level pulse mode, the user defines a pulse waveform

) for details on parameters.

)

Pulse measurement types (PMU)

The following table summarizes pulse measurement types that are available through LPT commands for the 4225-PMU. See Measurement types (on page 4-25

Pulse measurement types Measurement type Description

single current and voltage reading for the high level and low level (see the Spot

discrete measurements are performed for each pulse and then averaged to yield a

Waveform discrete

fall time portions of the pulse. A voltage and current reading is yielded for every sample taken on the pulse (see

measurements are performed on each pulse. The corresponding samples for each pulse are then averaged to yield a group of voltage and current readings for the

) for detailed information.

Measurement types (on page 4-25) Waveform

4200A-PMU-900-01 Rev. B March 2023 4-3

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4: Pulse card concepts Model 4200A-SCS Pulse Card (PGU and PMU)

Measure modes

The measure modes for the PMU are discrete pulses and average pulses.

Discrete pulses

For pulse I-V (spot mean), the averaged voltage or current readings for every sampled pulse period are acquired.

For waveform capture, enabled voltage and current readings and timestamps for every sample of the waveform are acquired.

For ITM operation, the readings are placed in the Analyze sheet.

See Spot mean discrete readings (on page 4-26) for details on the discrete pulses measure mode for pulse I-V. For UTM programming, the disc rete puls e meas ure mod e is call ed sp ot mean disc ret e. The pulse_meas_sm function is used to select the discrete acquisition type.

Waveform discrete readings (on page 4-28) for details on the discrete pulses measure mode for

See waveform capture. For UTM programming, the discrete pulse measure mode is called waveform discrete. The pulse_meas_wfm function is used to select the discrete acquisition type.

Average pulses

For pulse I-V (spot mean), the mean values of two or more pulses are averaged. Think of it as the "mean of the means."

For waveform capture, each acquired reading is a mean average of the corresponding samples for all the pulses in the burst.

See Spot mean average readings (on page 4-27) for details on the average pulses measure mode for pulse I-V. For UTM programmi ng, the av erage pulse measure mode is called spot mean average. The pulse_meas_sm function is used to select the average acquisition type.

See waveform capture. For UTM programming, the average pulses measure mode is called waveform discrete. The pulse_meas_wfm function is used to select the average acquisition type.

Waveform average readings (on page 4-29) for details on the average pulses measure mode for

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Pulse card concepts

High Power SMU (4210-S MU or 4211-SMU)

Not significant

4225-PGU

29.4

Not available

4225-PMU

50.4

Not available

4225-RPM

4.2

Not available

10 V PGU or PMU channel*

Not available

8.4

40 V PGU or PMU channel*

Not available

54.6

Medium Power SMU (4200-SMU or 4201-SMU)

Not significant

4210-CVU or 4215-CVU

Not significant

* There are two channels for each PGU and PMU instrument card.

-SCS Pulse Card (PGU and PMU) User's Manual Section 4:

4200A-SCS power supply limitations

In some system configurations, the 4200A-SCS power supply cannot supply enough current if a test has too many high-power instruments enabled. Some system configurations may have enough instruments installed to exceed the power supply limit if the selected test has too many channels enabled.

Clarius tracks the instruments used in a test and calculates the maximum power required and compares it to the maximum available power. If the test requires too much power, a message is displayed and the test will not run.

The following table and the equations below it show how the power is calculated. The maximum power available for each instrument in the test module is used in the calculation. The 4210-SMU High Power SMU, 4211-SMU High Power SMU, 4225-PMU Ultra-Fast Pulse Measure Unit, and 4220-PGU High Voltage Pulse Generator draw the majority of the power in the 4200A-SCS chassis.

There are two parts to the total power supply draw. The first part is the power required for the instruments while the 4200A-SCS is idle (on, but not testing). The second part is the power required by the instruments taking part in the test. Note that medium power SMUs (4200-SMUs and 4201-SMUs), 4200 preamplifiers (4200-PAs), and 4210-CVU and 4215-CVU modules are not included in the equations, as their power draw is not significant.

4200A-SCS power requirements Instrument Idle power Test power

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4: Pulse card concepts Model 4200A-SCS Pulse Card (PGU and PMU)

Equations to calculate power:

PowerIDLE = [(29.4 * nPGU) + (50.4 * nPMU) + (4.2 * nRPM)]

PowerTEST = [(45 * nHPSMU) + (8.4 * nC10) + (54.6 * nC40)]

PowerTOTAL = PowerIDLE + PowerTEST

PowerTOTAL = 500 maximum. If PowerTOTAL is less than or equal to 500, the test proceeds. Where:

• nPGU = number of 4220-PGU cards in the 4200A-SCS chassis (idle power draw)

• nPMU = number of 4225-PMU cards in the 4200A-SCS chassis (idle power draw)

• nRPM = number of 4225-RPM modules connected to PMUs (idle power draw)

• nHPSMU = number of High-Power SMUs (4210-SMUs or 4211-SMUs) in the test

• nC10 = number of 10 V PGU or PMU channels in the test

• nC40 = number of 40 V PGU or PMU channels in the test

Example 1: 4200A-SCS with two 4210-SMUs or 4211-SMUs, four 4225-PMUs, and eight 4225-RPMs. The test uses all eight PMU+RPM channels set to the 10 V range (no SMUs in test).

PowerIDLE = [(29.4 * nPGU) + (50.4 * nPMU) + (4.2 * nRPM)] = [(29.4 * 0) + (50.4 * 4) + (4.2 * 8)]

= 201.6 + 33.6 = 235.2

PowerTEST = [(45 * nHPSMU) + (8.4 * nC10) + (54.6 * nC40)] = [(45 * 0) + (8.4 * 8) + (54.6 * 0)]

= 67.2

PowerTOTAL = PowerIDLE + PowerTEST = 235.2 + 67.2 = 302.4

This test has PowerTOTAL ≤500, so this test will proceed. Example 2: 4200A-SCS with two 4210-SMUs or 4211-SMUs, four 4225-PMUs, and eight 4225-RPMs.

The test uses five PMU+RPM channels set to the 40 V range (no SMUs in test).

PowerIDLE = [(29.4 * nPGU) + (50.4 * nPMU) + (4.2 * nRPM)] = [(29.4 * 0) + (50.4 * 4) + (4.2 * 8)]

= 201.6 + 33.6 = 235.2

PowerTEST = [(45 * nHPSMU) + (8.4 * nC10) + (54.6 * nC40)] = [(45 * 0) + (8.4 * 0) + (54.6 * 5)]

= 273

PowerTOTAL = PowerIDLE + PowerTEST = 235.2 + 273 = 508.2

This test has PowerTOTAL >500, so this test will not proceed. Reduce the number of PMU+RPM

channels that are set to the 40 V range to less than five. The following table shows the 4200A-SCS power requirements for valid combinations for the

4225-PMU, 4225-RPM, and high-power SMU.

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Pulse card concepts

2 4 0 4 0

117.6

218.4

336 2 4 0 4 1 117.6

263.4

381

2 4 0 4 2

117.6

308.4

426

2 4 4 0 2

117.6

123.6

241.2

3 6 6 0 0

176.4

50.4

226.8

3 6 6 0 1

176.4

95.4

271.8

3 6 6 0 2

176.4

140.4

316.8

3 6 0 5 0

176.4

273

449.4

3 6 0 5 1

176.4

318

494.4

4 8 8 0 0

235.2

67.2

302.4

4 8 8 0 1

235.2

112.2

347.4

4 8 8 0 2

235.2

157.2

392.4

4 8 0 4 0

235.2

218.4

453.6

4 8 0 4 1

235.2

263.4

498.6

10 0 0

294

378 5 10

10 0 1

294

129

423 5 10

10 0 2

294

174

468 5 10 0 3 0 294

163.8

457.8

10 0 2 1 294

154.2

448.2

10 0 2 2 294

199.2

493.2

12 0 0

352.8

218.4

336

12 0 1

352.8

263.4

381

12 0 2 0 352.8

308.4

426 6 12 0 1 1 352.8

123.6

241.2

-SCS Pulse Card (PGU and PMU) User's Manual Section 4:

4200A-SCS power requirements for valid combinations of internal system instruments Idle power Power used in test nPMU nRPM nC10 nC40 nHPSMU PowerIDLE PowerTEST PowerTOTAL

The power limit check is performed in both ITMs and UTMs. In ITMs, exceeding the power limit will display a message similar to the one shown in the following figure when configuring PMU.

Figure 78: ITM maximum power exceeded message

For UTMs, the message appears in the Clarius Messages pane.

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4: Pulse card concepts Model 4200A-SCS Pulse Card (PGU and PMU)

Pulse source-measure concepts

Ultra-fast I-V sourcing and measurement have become increasingly important capabilities for many technologies, including compound semiconductors, medium-power devices, nonvolatile memory, microelectromechanical systems (MEMs), nanodevices, solar cells, and CMOS devices. Using pulsed I-V signals to characterize devices rather than DC signals makes it possible to study or reduce the effects of self-heating (joule heating) or to minimize current drift or degradation in measurements due to trapped charge. Transient I-V measurements allow scientists and engineers to capture ultra high-speed current or voltage waveforms in the time domain or to study dynamic test circuits. Pulsed sourcing can be used to stress test a device using an AC signal during reliability cycling or in a multi-level waveform mode to program or erase memory devices. The 4225-PMU Ultra-Fast I-V Module for the 4200A-SCS supports many of these high-speed sourcing and measurement applications.

Ultra-fast I-V tests

You can use the 4225-PMU to do these types of ultra-fast I-V tests:

• Pulsed I-V

• Transient I-V

• Pulsed sourcing

Pulsed I-V tests

Pulsed I-V tests are tests with a pulsed source and a corresponding high speed, timed-based measurement that provides dc-like results. The current plus voltage measurement is an average of readings made in a predefined measurement window on the pulse. This average of readings is called the spot mean. You can define the parameters of the pulse, including the pulse width, duty cycle, rise and fall times, and amplitude. You can use the train, sweep, or step mode.

Using pulsed I-V signals to characterize devices instead of dc signals makes it possible to study or reduce the effects of self-heating (Joule heating) or to minimize current drift or degradation in measurements due to trapped charge.

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-SCS Pulse Card (PGU and PMU) User's Manual Section 4:

Figure 79: Pulsed I-V tests

Transient I-V tests

Transient I-V, or waveform capture, is a time-based current or voltage measurement that is typically the capture of a pulsed waveform. A transient test is typically a single pulse waveform that is used to study time-varying parameters, such as the drain current degradation versus time due to charge trapping or self-heating. Transient I-V measurements can be made to test a dynamic test circuit or can be used as a diagnostic tool for choosing the appropriate pulse settings in the pulsed I-V mode.

Figure 80: Transient I-V tests

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T3 4 V3

T4 5 V3

4: Pulse card concepts Model 4200A-SCS Pulse Card (PGU and PMU)

Pulsed sourcing tests

Pulsed sourcing can involve any of the following:

• Outputting user-defined two-level pulses.

• Outputting multi-level pulses using the built-in Segment Arb

• Outputting an arbitrarily defined waveform using the arbitrary waveform generator in the KPulse

software. The Segment Arb feature allows you to create waveforms from segments defined with

separate voltages and time durations. In addition to its pulse generator capabilities, the 4225-PMU can measure ac or dc voltage and

current, thereby reducing the need for additional measurement hardware and more complicated programming. The 4220-PGU is a two-channel pulse generator with output capabilities identical to the capabilities of the 4225-PMU, but without its measurement functions.

function.

Figure 81: Pulsed sourcing tests

Sequence A definition

Segment Start V Stop V Duration

Sample rate

For the PMU, the maximum measurement sampling rate for each A/D test is 200e6 (200 million) samples per second. However, there is a limit to the number of samples (one million) that can be acquired per A/D test. When a test is configured to exceed that limit, the sample rate is automatically lowered when using ITMs so that fewer than one million samples are acquired.

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-SCS Pulse Card (PGU and PMU) User's Manual Section 4:

Pulse I-V (spot mean)

The maximum number of samples per A/D per test is <1,000,000 (one million). If an ITM is configured to yield more than one million samples, Clarius automatically lowers the sampling rate. For pulse I-V (spot mean), typically the sample rate is reduced only if the measure window is wide (due to a wide pulse width or period) or if the number of pulses is large.

The total number of samples for a test is calculated as follows:

Number of samples = Measure window x Sample rate × Number of pulses × Sweep points × Step

points

Example: Test that uses a single PMU to perform 50 20-step sweeps

Pulse width = ~7 μs

Measure window = 1 μs

Sample rate = 200e6 samples per second

Number of pulses = 50

Number of steps in sweep = 20 The number of samples acquired for the above example is calculated as follows:

Number of samples = 1 μs x 200e6 x 50 x 20 = 200,000 Because the number of samples is less than the one million sample limit, the sample rate of 200e6

samples per second is used for the above example.

Segment Arb waveform

Each channel of a pulse card can be configured to output its own unique Segment Arb® waveform. A Segment Arb waveform is composed of user-defined line segments, up to 2048 for the 4220-PGU and 4225-PMU. Each segment can have a unique time interval, start value, stop value, output trigger level (TTL high or low) and output relay state (open or closed).

If both channels of a pulse card are being used, the segment trigger levels for Channel 1 will be seen at the TRIGGER OUT connector. The trigger levels for Channel 2 are ignored.

A Segment Arb waveform consists of line segments illustrated in the figure below. The blue line represents the voltage waveform; the red represents the measure windows. This figure contains a 12-segment waveform.

4200A-PMU-900-01 Rev. B March 2023 4-11

Tektronix 4200A-SCS User manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Safety precaut ions

Table of contents

Models 4220-PGU and 4225-PMU

Introduction

Connections

Introduction

Connection guide lines

PMU common connections

Shield connections

Cable length

High frequency connections

Prober chuck connections

PGU and PMU connectors

Model 4225-RPM

RPM input, output, and top panels

RPM wiring diagram

Connecting the RPM to the PMU

Mounting the RPM

RPM diagrams for local and remote sensing

Using the RPM as a switch

Control RPM switching

Two-terminal device connections

Three-terminal device connections

Four-terminal device connections

Pulse source-measure connections

Pulse generator connections

Using an adapter cable to connect pulse card to DUT

Connections to prober or test fixture bulkhead connectors

RPM connections to DUT

Two-terminal test connections

Remote sensing using RPM connections to a prober

PMU connection compensation

Short compensation

Offset current compensation

Perform connection compensation

Enabling connection compensation

Load-line effect compensation (LLEC) for the PMU

Methods to compensate for load-line effect

How LLEC adjusts pulse output to the target levels

LLEC maintains even voltage spacing

Test considerations

LPT functions used to configure LLEC

Enable LLEC

Disable LLEC and set the output impedance

Setting up PMUs and PGUs in Clarius

Introduction

Configure the PGU, PMU, and RPM using tests

Create a PMU pro ject

Configure the tests

PMU operation modes

PMU - all terminal p arameters

Start (PMU Amplitude Sweep)

Stop (PMU Amplitude Sweep)

Step (Pulse Amplitude Sweep)

Points

Base

Amplitude

Dual Sweep (pulse)

Force Range (PMU)

Disable outputs at completion

Current Spot Mean High

Current Spot Mean Low

Measure Current Range (PMU)

Low Range

Current Sample Waveform

Voltage Spot Mean High

Voltage Spot Mean Low

Voltage Sample Waveform

Report Timestamps

Report Status (PMU)

PMU measurement status

Status codes

Compensation Short Connection

Load Line Effect Compensation

DUT Resistance (R DUT)

Max Voltage Estimator