Keithley Keithley Instruments 7072-HV Manual

Model 7072-HV

High Voltage Semiconductor Matrix Card
Instruction Manual

A GREATER MEASURE OF CONFIDENCE

Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 - TestEquipmentDepot.com

W ARRANTY

Keithley Instruments, Inc. warrants this product to be free from defects in material and workmanship for a period of 1 year
from date of shipment.

Keithley Instruments, Inc. warrants the following items for 90 days from the date of shipment: probes, cables, rechargeable
batteries, diskettes, and documentation.

During the warranty period, we will, at our option, either repair or replace any product that proves to be defective.

To exercise this warranty, write or call your local Keithley representative, or contact Keithley headquarters in Cleveland, Ohio.
You will be given prompt assistance and return instructions. Send the product, transportation prepaid, to the indicated service
facility. Repairs will be made and the product returned, transportation prepaid. Repaired or replaced products are warranted for
the balance of the original warranty period, or at least 90 days.

LIMIT A TION OF W

ARRANTY

This warranty does not apply to defects resulting from product modification without Keithley’s express written consent, or
misuse of any product or part. This warranty also does not apply to fuses, software, non-rechargeable batteries, damage from
battery leakage, or problems arising from normal wear or failure to follow instructions.

THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING ANY
IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. THE REMEDIES PRO­VIDED HEREIN ARE BUYER’S SOLE AND EXCLUSIVE REMEDIES.

NEITHER KEITHLEY INSTRUMENTS, INC. NOR ANY OF ITS EMPLOYEES SHALL BE LIABLE FOR ANY DIRECT,
INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF ITS
INSTRUMENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS, INC., HAS BEEN ADVISED IN ADVANCE
OF THE POSSIBILITY OF SUCH DAMAGES. SUCH EXCLUDED DAMAGES SHALL INCLUDE, BUT ARE NOT LIM­ITED TO: COSTS OF REMOVAL AND INSTALLATION, LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY
PERSON, OR DAMAGE TO PROPERTY.

Keithley Instruments, Inc.

Sales Offices BELGIUM: Bergensesteenweg 709 • B-1600 Sint-Pieters-Leeuw • 02-363 00 40 • Fax: [phone]

CHINA: Yuan Chen Xin Building, Room 705 • 12 Yumin Road, Dewai, Madian • Beijing 100029 • 8610-6202-2886 • Fax: [phone]
FINLAND: Tietäjäntie 2 • 02130 Espoo • Phone: [phone] • Fax: [phone]
FRANCE: 3, allée des Garays • 91127 Palaiseau Cédex • 01-64 53 20 20 • Fax: [phone]
GERMANY: Landsberger Strasse 65 • 82110 Germering • 089/84 93 07-40 • Fax: [phone]
GREAT BRITAIN: Unit 2 Commerce Park, Brunel Road • Theale • Berkshire RG7 4AB • 0118 929 7500 • Fax: [phone]
INDIA: Flat 2B, Willocrissa • 14, Rest House Crescent • Bangalore 560 001 • 91-80-509-1320/21 • Fax: [phone]
ITALY: Viale San Gimignano, 38 • 20146 Milano • 02-48 39 16 01 • Fax: [phone]
KOREA: FL., URI Building • 2-14 Yangjae-Dong • Seocho-Gu, Seoul 137-130 • 82-2-574-7778 • Fax: [phone]
NETHERLANDS: Postbus 559 • 4200 AN Gorinchem • 0183-635333 • Fax: [phone]
SWEDEN: c/o Regus Business Centre • Frosundaviks Allé 15, 4tr • 169 70 Solna • 08-509 04 679 • Fax: [phone]
SWITZERLAND: Kriesbachstrasse 4 • 8600 Dübendorf • 01-821 94 44 • Fax: [phone]
TAIWAN: 1FL., 85 Po Ai Street • Hsinchu, Taiwan, R.O.C. • 886-3-572-9077• Fax: [phone]

© Copyright 2001 Keithley Instruments, Inc.

Printed in the U.S.A.

11/01

Model 7072-HV High V oltage Semiconductor Matrix Card

Instruction Manual

©1990, Keithley Instruments, Inc.

All rights reserved.

Cleveland, Ohio, U.S.A.

Second Printing, January 2002

Document Number: 7072-HV-901-01 Rev. B

Manual Print History

The print history shown below lists the printing dates of all Revisions and Addenda created for this manual. The
Revision Level letter increases alphabetically as the manual undergoes subsequent updates. Addenda, which are
released between Revisions, contain important change information that the user should incorporate immediately into
the manual. Addenda are numbered sequentially. When a new Revision is created, all Addenda associated with the
previous Revision of the manual are incorporated into the new Revision of the manual. Each new Revision includes
a revised copy of this print history page.

Revision A (Document Number 7072-901-01) ............................................. February 1988

Revision B (Document Number 7072-901-01) ................................................... April 1988

Addendum B (Document Number 7072-901-02)................................................ April 1988

Addendum B (Document Number 7072-901-03).......................................... February 1996

Revision C (Document Number 7072-901-01) ................................................... April 2000

All Keithley product names are trademarks or registered trademarks of Keithley Instruments, Inc.
Other brand and product names are trademarks or registered trademarks of their respective holders.

SAFETY PRECAUTIONS

The following safety precautions should be observed before using the Model 707%HV and the associated instruments.

This matrix card is intended for use by qualified personnel who recognize shock hazards and are familiar with the safety

precautions required to avoid possible injury. Read over this manual carefully before using the matrix card.

Exercise extreme caution when a shock hazard is present at the test circuit. User-supplied lethal voltages may be present
on the card connector jacks. The American National Standards Institute (ANSI) states that a shock hazard exists when
voltage levels greater than 30V RMS or 42.4V peak are present. A good safety practice is to expect that hazardous voltage
is present in any unknown circuit before measuring.

Do not exceed 13OOV between signal or guard and earth ground on Rows A and B.

Do not exceed ZOOV between any two pins or between any pin and earth ground on Rows C through H.

Inspect the connecting cables and test leads for possible wear, cracks, or breaks before each use.

For maximum safety, do not touch the test cables or any instruments while power is applied to the circuit under test.

Turn off the power and discharge any capacitors before connecting or disconnecting cables from the matrix card.

Do not touch any object which 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, insulated surface capable of with-

standing the voltage being measured.

Do not exceed the maximum allowable input of the matrix card, as defined in the specifications and operation section of
this manual.

Instrumentation and accessories should not be connected to humans.

Safety Precautions

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

This product is intended for use by qualified personnel who recog­nize shock hazards 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 manual for complete product specifications

If the product is used in a manner not specified, the protection pro­vided by the product 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 specif cations 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 manual. 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, and perform

safe installations and repairs of products. Only properly trained ser­vice personnel may perform installation and service procedures.

Keithley products are designed for use with electrical signals that
are rated Installation Category I and Installation Category II, as de­scribed in the International Electrotechnical Commission (IEC)
Standard IEC 60664. Most measurement, control, and data I/O sig­nals are Installation Category I and must not be directly connected
to mains voltage or to voltage sources with high transient over-volt­ages. Installation Category II connections require protection for
high transient over-voltages often associated with local AC mains
connections. Assume all measurement, control, and data I/O con­nections are for connection to Category I sources unless otherwise
marked or described in the Manual.

Exercise extreme caution when a shock hazard is present. Lethal
voltage may be present on cable connector jacks or test f xtures. The
American National Standards Institute (ANSI) states that a shock
hazard exists when voltage levels greater than 30V RMS, 42.4V
peak, or 60VDC are present.

that hazardous voltage is present in any unknown circuit before
measuring.

A good safety practice is to expect

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 volts,

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, make sure 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, insulated
surface capable of withstanding the voltage being measured.

The instrument and accessories must be used in accordance with its
specif cations and operating instructions or the safety of the equip­ment may be impaired.

Do not exceed the maximum signal levels of the instruments and ac­cessories, as def ned in the specif cations and operating informa­tion, and as shown on the instrument or test f xture panels, or
switching card.

When fuses are used in a product, replace with same type and rating
for continued protection against f re hazard.

Chassis connections must only be used as shield connections for
measuring circuits, NOT as safety earth ground connections.

If you are using a test f xture, keep the lid closed while power is ap­plied to the device under test. Safe operation requires the use of a
lid interlock.

no conductive part of

If a screw is present, connect it to safety earth ground using the
wire recommended in the user documentation.

!

The symbol on an instrument indicates that the user should re­fer to the operating instructions located in the manual.

The symbol on an instrument shows that it can source or mea­sure 1000 volts or more, including the combined effect of normal
and common mode voltages. Use standard safety precautions to
avoid personal contact with these voltages.

The

WARNING heading in a manual explains dangers that might

result in personal injury or death. Always read the associated infor­mation very carefully before performing the indicated procedure.

The

CAUTION heading in a manual explains hazards that could

damage the instrument. Such damage 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 f re, replacement
components in mains circuits, including the power transformer, test
leads, and input jacks, must be purchased from Keithley Instru­ments. Standard fuses, with applicable national safety approvals,
may be used if the rating and type are the same. Other components
that are not safety related may be purchased from other suppliers as
long as they are equivalent to the original component. (Note that se­lected parts should be purchased only through Keithley Instruments
to maintain accuracy and functionality of the product.) If you are
unsure about the applicability of a replacement component, call a
Keithley Instruments off ce for information.

To clean an instrument, use a damp cloth 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., 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.

11/01

MODEL 7072-HV

High Voltage

Semiconductor Matrix Card

ROWS:
CROSSPOINT

CONFIGURATION:
OFFSET CURRENT:
PATH ISOLATION:

Resistance:

Capacitance bvxninal):
CROSSTALK: 1 MHz, 5oO load @picaI):
3dB BANDWIDTH @picaI), 500 load:
RELAY DRWE CURRENT

(per cmsspoint):

MAXIMUM SIGNAL LEVEL

Maximum between any 2 pins or chassis:

Maximum between Signal and Guard:

1A carry/0SA switched,

1OVA peak (resistive load)
CONTACT POTENTIAL (Signal to Guard):

MATRIX CONFIGURATION: 8 rows by I2

columns.

CONNECTOR TYPE: Three-lug triaxial

(Signal, Guard, Chassis).

CONTACT LIFE:

Cold Switching: IO’closures.
At Maximum Signal Level: 105 closures.

PATH RESISTANCE (per conductor): <IO

initial, <3.5Q at end of contact life.

RELAY SE’ITLING TIME <15ms.

Law Current General Purpose

(A-B) (C-F) (G-H)

2-p& Form A

4 pA

>1013 0

0.4 pF

<A0 dB

4MHZ

40m.4

1300”

2oov

<5o!lv

INSERTION LOSS UMHz, 50O source, 5OQ

load): O.ldB typical.

ENVIRONMENT:

OFFSETCURRENTandPATHISOLATION

Specificaticmc 23°C ~60% R.H.
Operating: 0’ to 5O”C, up to 35°C at 70% RH.
Storage: -25’ to +65*C.

ACCESSORY SUPPLIED: Instrnction manual.

Specifications subject to change without notice.

2-p& Form A I-pole Form A,

~20 pA

>lP R

1 PF

<A0 dB <-50 dB

8MHz 5MHZ

6Om.4

200”
2oov

<2opv

c-v

Common Guard

<20 pA

>10’2 n

0.6 pF

80 mA

2oov
2oov

<2ojlv

Contains information on Model 707%HV features, specifi-

cations, and accessories.

Details installation of the Model 70724-N Semiconductor
Matrix Card within the Model 707 Switching Matrix, cov­ers card connections, and also discusses measurement
considerations.

Gives four typical applications for the Model 707.2~HV, in-

cluding combined quasistatic and high-frequency CV
measurements, semiconductor switching matrix, van der
Pauw resistivity measurements, and semiconductor pa­rameter analysis.

SECTION 1

General Information

SECTION 2

Operation

SECTION 3

Applications

Contains performance verification procedures, trouble­shooting information and principles of operation for the
matrix card.

Lists replacement parts, and also includes component lay­out and schematic drawings for the Model 707%HV.

SECTION 4

Service Information

SECTION 5

Replaceable Parts

Table of Contents

SECTION 1 — General Information

1.1 INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.2 FEATURES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.3 WARRANTY INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.4 MANUAL ADDENDA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.5 SAFETY SYMBOLS AND TERMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.6 SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

1.7 UNPACKING AND INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

1.7.1 Inspect for Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

1.7.2 Shipment Contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

1.7.3 Instruction Manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

1.8 REPACKING FOR SHIPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

1.9 OPTIONAL ACCESSORIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

1.10 COAXIAL JUMPER ACCESS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

SECTION 2 — Operation

2.1 INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

2.2 HANDLING PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

2.3 ENVIRONMENTAL CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

2.4 CARD INSTALLATION AND REMOVAL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

2.5 CONNECTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

2.5.1 Card Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

2.5.2 Recommended Cables and Adapters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

2.5.3 Triaxial to Banana Plug Adapter Preparation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

2.5.4 General Instrument Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

2.5.5 Keithley Instrument Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11

2.5.6 Typical Test Fixture Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14

2.6 MATRIX CONFIGURATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17

2.6.1 Switching Matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17

2.6.2 Row and Column Isolators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-18

2.6.3 Pathway Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-18

2.6.4 Internal Matrix Expansion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19

2.6.5 External Matrix Expansion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20

2.7 MEASUREMENT CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23

2.7.1 Magnetic Fields. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23

2.7.2 Electromagnetic Interference (EMI). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23

2.7.3 Ground Loops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24

2.7.4 Keeping Connectors Clean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24

2.7.5 Noise Currents Caused by Cable Flexing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24

2.7.6 Shielding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24

2.7.7 Guarding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25

2.7.8 Matrix Expansion Effects on Card SpeciÞcations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27

SECTION 3

- Applications

3.1

3.2

3.2.1

3.2.2

3.2.3

3.2.4

3.2.5

3.3

3.3.1

3.3.2

3.4

3.4.1

3.4.2

3.4.3

3.5

3.5.1

3.5.2

3.6

3.6.1

3.6.2

3.6.3

3.6.4

INTRODUCTION .........................

CV MEASUREMENTS .....................

Stand Alone System Configuration ..........

Computerized System Configuration
Optimizing CV Measurement Accuracy

Basic CV Test Procedure ..................

Typical CV Curves ......................

SJ?MICONDUCTOR TEST MATRIX ...........

system Conf&uration ....................

Testing Common-Source Characteristic of FETs

REs1sTMTY MEASUREMENTS .............

Test Configuration

Test Procedure .........................

Resistivity CaIculations ...................

Semiconductor IV Characterization ............

TestConfiguration ......................

CableConnections ......................

SEMICONDUCTOR PARAMETER ANALYSIS

system Configuration ....................

CableConnections ......................

SPA Measurement Considerations ..........

Typical Test Procedure ...................

......................

........

......

...

...................

...................

...................

...................

...................

...................

...................

...................

...................

...................

...................

...................

...................

...................

...................

...................

...................

....................

...................

...................

...................

3-l
3-1
3-l
3-1
3-4
3-4

3-4
3-6
3-6
3-7
3-8
3-9
3-10
3-12
3-12
3-12
3-12

3-12
3-14

3-15
3-15
3-15

SECTION 4

4.1

4.2

4.3

4.3.1

4.3.2

4.3.3

4.3.4

4.3.5

4.3.6

4.4

4.5

4.5.1

4.5.2

4.5.3

4.6

4.6.1

4.6.2

4.6.3

4.6.4

4.6.5

INTRODUCTTON ...............................

HANDLING AND CLEANING PRECAUTIONS

PERFORMANCE VERIFICATION ..................

EnvironmentalConditions ......................

Recommended Test Equipment ...................

RelayTesting ................................

Offset Current Verification ......................

PathIsolationVt?rification .......................

Path Resistance Verification .....................

SPECIAL HANDLING OF STATIC- SENSITIVE DEVICES

TROUBLESHOOTING ...........................

Recommended Equipment ......................

Using the Extender Card ........................

Troubleshooting Procedure ......................

PRINCIPLES OF OPERATION .....................

Block Diagram ...............................

IDDataCircuits ..............................

RelayControl ................................

Power-on Safeguard ...........................

Isolator Relays ...............................

- Service Information

.......

.................

.................

.................

.................

.................

.................

.................

.................

.................

.................

.................

.................

.................

.................

.................

.................

.................

.................

.................

.................

4-l
4-1
4-1

4-l
4-l
4-1
4-3
4-5
4-7

4-9
4-9
4-9
4-Y
4-9
4-11

4-11
4-l 1

4-12
4-12
4-12

SECTION

5 - Replaceable Parts

5.1

5.2

5.3

5.4

5.5 COMPONENT LAYOUT AND SCHEMATIC DIAGRAM

INTnODUCTION.............................................................. 5-l

PARTSLIST . . . . . . . . . . ..___..__......__...........__..........................

ORDERING INFORMATION .

FACTORYSERVICE................................................,........... 5-l

5-l
5-1

5-l

List of Illustrations

SECTION

Figure 2-l
Figure 2-2
Figure 2-3
Figure 2-4
Figure 2-5
Figure 2-6

Figure 2-7
Figure 2-8
Figure 2-9
Figure 2-10
Figure 2-11
Figure 2-12
Figure 2-13
Figure 2-14
Figure 2-15

Figure 2-16
Figure 2-17
Figure 2-18
Figure 2-19
Figure 2-20
Figure 2-21
Figure 2-22

Figure 2-23
Figure 2-24

2 - Operation

Model7072-HVInstalIation
CardConnectors
Triax Connector Configuration
Triaxial Cable Preparation

General Inshument Connections
Model 617 Electrometer Connections
Model196DMMConnections
Model 230 Voltage Source Connections
Model 590 CV Analyzer Connections
Model 220 Current Source Connections
Typical Test Fixture Connections

Equivalent Circuit of Test Fixture Connections .
Model 7072.HV Matrix Organization
CoMectingThreeCardsforSx36Mahix

Jumper Connector Locations

Three Cards in Daisy Chain Configuration

l6x36MatrixConstmctedbyExtemalJumpering
Using Triax Tee Adapters to Daisy Chain Cards
Power Line Ground Loops

Eliminating Ground Loops

Shielding Example ................

Dual Shield Test Fixture

Guarded Circuit ..................

Typical Guarded Signal Connections

..................................................

.........................................

.......................................

...........................................

......................................

...................................

........................................

.................................

..................................

.................................

.....................................

..................................

...............................

.........................................

..............................

..........................

..........

..........

............

...

.........................

.

...........

...........

2-2
2-3
2-4
2-5

26
2-11
2-12
2-13
2-14
2-15

2-16
2-16
2-17
Z-19
2-19
2-20
2-21

2-22
2-24
2-24
2-25
2-26
2-26
2-27

SECTION

Figure 3-1

Figure 3-2
Figure 3-3
Figure 3-4
Figure 3-5
Figure 3-6
Figure 3-7

Figure 3-8
Figure 3-9
Figure 3-10
Figure 3-11
Figure 3-12

Figure 3-13
Figure 3-14

3 - Applications

Stand Alone CV System Configuration
Computerized CV System Configuration
Typical Quasistatic CV Curve Generated by Model 595
Typical High-frequency CV Curve Generated by Model 590
SemiconductorTestMatrix..

System Configuration for Measuring Common-Emitter Characteristics
Typical Common-Source FET IV Characteristics
Resistivity Test Configuration
Resistivity Measurement Conventions
Multi Unit Test System Using Models 236 and 237 Source Measure Units

Semiconductor Parameter Analysis Switching System

SPAConnections ................................................

System Configuration for JFET Test

TypicalJFETPlot ................................................

.......................................

.......................................

................................

..............................

....................

................

.........................

................................

.....................

...................................

........

.......

3-2
3-3
3-5
3-6
3-7

.

3-8
3-a
3-9
3-11
3-13

3-14
3-16
3-17
3-18

SECTION 4

- Service Information

Figure 4-1
Figure 4-2
Figure 4-3
Figure 4-4

Figure 4-5

Figure 46
Figure 4-7
Figure 4-8

Figure 4-Y

Test Cable Preparation
Connecting the Test Cable to the Model 7072.HV
Offset Verification Test Connections
Connections for Path Isolation Verification
Triaxial Cable Preparation
Connections for path Res@tance Verification
Shorting Measurement Paths Using Triax Tee Adapter
IDDataTig
Model 7072~HV Block Diagram

....................................

..........

............................

., ...................

..........

....................

...............

..............

........................

......

4-2

4-3
4-4
4-5

4-6

4-7

4-8

4-10

4-11

List of Tables

SECTION 2

Table 2-l
Table 2-2
Table 2-3

SECTION 3

Table 3-l CV Test Crosspoint Summary .
Table 3-2
Table 3-3

SECTION

Table 4-1
Table 42
Table 4-3

- Operation

Recommended Cables and Adapters ...........

Parts for Special Triaxial Cable ...............

Column Numbering by Slot and Unit ..........

- Applications

Crosspoint Summary for Resistivity Measurements
Crosspoint Summary for JFET Test

4 - Service Information

Recommended Verification Equipment
Recommended Troubleshooting Equipment

Troubleshooting Procedure L

................... 2-4

................... 24

. ................... 2-18

...................

...................

...................

................... 4-2

.................... 4-9

................... 4-10

34
3-10
3-15

SECTION 1

General Information

1 .l INTRODUCTION

This section contains general information about the
Model 7072~HV Semiconductor Matrix Card. The Model

7072-HV is designed for flexibility in switching semicon­ductor test setups. Two low-current, high voltage path­ways, and two C-V pathways in addition to four general­purpose pathways allow complete system versatility.

Section 1 is arranged in the following manner:

1.2 Ff?&lI~S

1.3 warranty Information

1.4 Manual Addenda

Safety Symbols and Terms

1.5

1.6 Specifications
Unpacking and Inspection

1.7

1.8 Repacking for Shipment

1.3 WARRANTY INFORMATION

Warranty information is located on the inside front cover
of this instruction manual. Should your Model 7072~HV
require warranty service, contact the Keithley represen­tative or authorized repair facility in your area for further
information. When returning the matrix card for repair,
be sure to fill out and include the service form at the back
of this manual in order to provide the repair facility with
the necessary information.

1.4 MANUAL ADDENDA

Any improvements or changes concerning the mati
card or manual will be explained in an addendum in­cluded with the the unit. Be sure to note these changes
and incorporate them into the manual before using or
servicing the unit.

1.5 SAFETY SYMBOLS AND TERMS

The following symbols and terms may be found on an in-

strument or used in this manual.

1.9 Optional Accessories

1.10 Coaxial Jumper Access

1.2 FEATURES

Key features of the Model 7072~HV High Voltage Semi­conductor Matrix Card include:

. 8 x 12 (eight row by 12 column) switching matrix.
. Two rows (A and B) with low offset current for low-

current, high voltage measurements.

. Two dedicated rows (G and H) for CV measurements.

l

Three-lug hiax connectors for all row and columns al­low guarding of each signal pathway to minimize the
effects of stray capacitance, leakage current, and leak­age resista&. -

l

Model 7072~HV cards can be connected together to ex-

pand the number of columns in the matrix.

The A
user should refer to the operating instructions located in
the instruction manual.

The t symbol
may be present on the terminal(s). Use standard safety
precautions to avoid personal contact with these volt-

ages.

The WARNING heading used in this manual explains

dangers that might result in personal injury or death. Al­ways read the associated information very carefully be­fore performing the indicated procedure.

The CAUTION heading used in this manual explains
hazards that could damage the matrix card. Such damage
may invalidate the warranty.

symbol on an instrument indicates that the

on an instrument shows that high voltage

l-1

SECTION 1
General Information

1.6 SPECIFICATIONS

Model 7072~HV specifications may be found at the front

of this manual. These specifications are exclusive of the

matriv mainframe specifi~tiom,

Model 707 Instruction Manual.

which are located in the

1.7 UNPACKING AND INSPECTION

1.7.1

Upon receiving the Model 7072~HV, carefully unpack it
from its shipping cation and inspect the card for any ob­vious signs of physical damage. Report any such damage
to the shipping agent immediately. Save the original
packing carton for possible future reshipment.

1.7.2

The following items are included with every Model
7072~HV order:

l Model 7072-HV Semiconductor Ma&ix Card.

. Model 7072~HV Instruction Manual.

l Coaxial jumper cables (4) for matrix expansion.

. Additional Accessories as ordered.

Inspection for Damage

Shipment Contents

1.7.3 Instruction Manual

1.6 REPACKING FOR SHIPMENT

Should it become necessary to return the Model 7072~HV
for repair, carefully pack the card in its original packing
carton or the equivalent, and include the following infor­mation:

. Advise as to the warranty status of the mati card.
. Write ATTENTION REPAIR DEPARTMENT on the

shipping label.

l Fii out and include the service form located at the back

of this manual.

1.9 OPTIONAL ACCESSORIES

Model 707%TBC 3-Lug Female Triax Bulkhead Connec­tor with Cap-The Model 707%TBC can be used for ap­plications such as test fixtures.

Model 7078-CSHP Cable Set-The Model 707%CSHP
Cable Set includes the necessary cables and adapters to

connect the Model 7072~HV to the Hewlett-Packard
Model 4145 Semiconductor Parameter Analyzer. The
Model 7078~CSHI’ includes four Model 707%TRX-10

loft. 3-lug triaxial cables, four Model 7051-10 loft. BNC

cables, and four Model 7078-TRX-BNC 3-lug triax to BNC
adapters.

The Model 7072~Hv Instruction Manual is three-hole

drilled so that it can be added to the three-ring binder of
the Model 707 Switching Matrix Instruction Manual. Af­ter removing the plastic wrapping, place the manual in
the binder after the mainframe instruction manual. Note
that a manual identification tab is included and should
precede the matrix card instruction manual.

If an additional instruction manual is required, order the
manual package, Keithley part number 7072~HV-901-00.

The manual package indudes an inshuction manual and

any perhnent addenda.

l-2

Recommended cables and adapters are summarized in
Table 2-1.

1.10 COAXIAL JUMPER ACCESS

Coaxial jumpers can be installed to expand rows A, B, G
and H of the matrix using two or more Model 7072~HV
Cards. An access door on the mainframe allows access to
these jumpers. To allow access when the Model 707 is
mounted in a rack, it is recommended that the Model

7079 Slide Rack Mount Kit be used.

SECTION 2

Operation

2.1 INTRODUCTION

This section contains information on matrix card connec-

tions, installation and matrix programming, and is ar­ranged as follows:

2.2 Handling Precautions: Discusses precautions that
should be taken when handling the card to avoid con­tamination that could degrade performance.

2.3 Environmental Considerations: Outlines environ­mental aspects of using the Model 7072~HV.

2.4 Card Installation and Removal: Details installation
in and removal from the Model 707 Switching Matrix
mainframe.

2.5 Connections: Discusses card connectors, cables and
adapters, and typical connections to other instnunenta-

tion.

2.6 Matrix Configuration: Discusses the switching ma­trix, as well as matrix expansion by connecting two or
more cards together.

2.7 Measurement Considerations: Reviews a number
of considerations when making low-level current and ca­pacitance measurements.

ment. If contamination is suspected, clean the card as dis-

cussed in Section 4. Also, the performance verification
procedures in Section 4 can be used to test the card for
low leakage resistances that could signal contamination.

2.3 ENVIRONMENTAL CONSIDERATIONS

For rated performance, the card should be operated
within the temperature and humidity limits given in the
specifications at the front of this manual. Note that cur­rent offset and path isolation values are specified within a
lower range of limits than the general operating environ­ment.

2.4 CARD INSTALLATION AND REMOVAL

Before making connections, the Model 7072.HV should
be installed within the Model 707 Switching Matrix, as
summarized below. Figure 2-1 shows the installation
procedure.

WARNING
Turn off the mainframe power and discon­nect the line cord before installing or remov­ing matrix cards.

2.2 HANDLING PRECAUTIONS

To maintain high impedance isolation, care should be

taken when handling the matrix card to avoid contami-

nation from such foreign materials as body oils. Such

contamination can substantially lower leakage resis­tances, degrading performance. The areas of the card that
are most sensitive to contamination are those associated
with the Teflon@ insulators. To avoid any possible con­tamination, always grasp the card by the handle or the
card edges. Do not touch board surfaces, components, or
card edge connectors.

Dirt build-up over a period of time is another possible

source of contamination. To avoid this problem, operate
the mainframe and matrix card only in a clean environ-

NOTE
The coaxial jumpers used to expand the ma­trix with two or more Model 7072~HV cards
are not installed before card insertion; an ac­cess door on top of the mainframe allows ac-

cess to the connectors after the card is in-

stalled.

1. Before installing the card, make sure the access door
on top of the Model 707 is fully closed and secured.
The access door contains tracks for the card slots and
must be in place to properly install the card.

2. With one hand grasping the handle, and the other
holding the bottom of the card, line up the card with
the tracks in the desired slot. Make certain that the
component side of the card is facing the fan on the
mainframe.

2-l

SECTION 2
Operation

Figure 2-1. Model 7072.HV Installation

CAUTION

hveen the card and the mainframe. Failure to
Donot touchthecard sufacesoranycompo- properly secure this ground connection may
nerds to avoid contamination that could de- result in personal injury or death due to elec­grade card performance. tric shock.

3. Slide the card into the mainframe until it is properly
seated in the edge connectors at the back of the slot.
Once the card is properly seated, secure it to the
mainframe by finger tightening the spring-loaded
screws.

4. To remove a card, first turn off the power and dis­connect the line cord from the mainframe. Discon­nect all external and internal cables (internal cables
can be reached through the access door). Loosen the
mounting screws, then pull the card out of the main-

WARNING frame by the handle. When the back edge of the card
The mounting screws must be secured to en- clears the mainframe, support it by grasping the bot­sure a proper chassis ground connection be- tom edge near the back edge.

2-2

SECTlON 2

Operation

2.5 CONNECTIONS

Card connectors, recommended cables and adapters, and
typical connections to test inshunents are discussed in
the following paragraphs.

2.5.1

The card connectors are shown in Figure 2-2. Each row

and column is equipped with a 3-lug female triax connec­tor. As shown in Figure 2-3, the center conductor is SIG­NAL, the inner shield is GUARD, and the outer shield, or
shell is chassis ground. Note that 3-lug connectors are
used to avoid possible damage from inadvertently at­tempting to connect BNC cables.

Card Connectors

CAUTION
Do not exceed 200V between any two pins on
rows C-H or SIGNAL and GUARD on rows
A and B, or 1300V between SIGNAL and

chassis ground, or GUARD and chassis
ground on rows A and 8.

ROWS

A-H

Carrying

Handle

Mounting

SCrW

-Columns
i-12

w

The Model 7072~HV has 12 columns that are labeled 1

through 12, as well as eight rows, A through H. Rows A
andBarelabeledLOWIandareintendedforlow-current
or high voltage measurements. Rows G and Hare labeled
CV and are designed for capacitance-voltage measure­ments. Rows C through F are general purpose rows that
can be used for ordinary voltage, current, or resistance
measurements. If a crosspoint in row A or B is closed, the

crosspoints in rows C through H of that column will nOt

be connected to rows A and B. This is to prevent high

voltage from being accidentally applied to rows C
through H.

2.5.2

Recommended Cables and
Adapters

Table 2-l summarizes the cables and adapters recom-

mended for use with the Model 7072~HV. Equivalent
user-supplied items may be substituted as long as they
are of sufficient quality (low offset current, high leakage
resistance). Using substandard cables and adapters may

degrade the integrity of the measurements made using
the matrix card. See paragraph 2.7 for a discussion of
measurement considerations.

Mounting

SCMV

Figure 2-2. Card Connectors

23

SECTION 2

Operation

Chassis
Ground

* 2OOV Max on Caution : Do not Exceed Maximum

rows C-H Voltage Levels Shown

?aure 23.

Table 2-l. Recommended Cables and Adapters

1 Model

7078-TRX-x
237-BRE-1
237-BAN-3
237-ALG-1

6011*
237-BAN

7078~TRX-BNC

7078-TRX-GND

7078-TRX-T
237-SBT-NG
6171”

Triax Connector Confimuation

plug

3-slot male triax to alligator clips

Z-slot male triax to alligator clips
3-slot male triax to female banana
jack adapter
3slot male triax to BNC adapter,
connections to center and inner
shell
3-slot male triax to BNC adapter,
connections to center and outer
shell
3-slot male to dual 3-lug female
triax tee adapter
3-slot male to Slug female adapt­er, guard disconnected
3slot male triax to 2-lug female
triax adapter

2.5.3 Triaxial to Banana Plug Adapter
Preparation

For instruments that use banana jacks, a special 3-slot
triax-to-single banana plug must be prepared, as dis­cussed below. This special cable can be prepared as out­lined below using the parts listed in Table 2-2 or may be
purchased as a Model 237-BAN-3. Note that you can use
either an unterminated triax cable, or cut a dual-connec-

tor cable (7078-TRX-10) in half to construct two cables.
The steps for the procedure below are shown in Figure
2-4.

Table 2-2. Parts for Special Triaxial Cable

Keithley Part or
Model Number 1 Description

7078-TRX-3 triax cable” Unterminated 3slot triax

cable

Part #

BG-10-Z

‘One ConneCtor must be cut off

1. Using a knife, cut and strip back the outer insolation
about l-1/2 inches.

2. Remove the outer insulation, then cut away the outer
shield back as far as the insulation is stripped.

3. Carefully strip away the insulation over the inner
shield one inch, then cut the inner shield off even
with the shipped insulation.

4. Strip the inner conductor l/2 inch, then twist the
strands together.

5. Unscrew the cover from a banana plug, then slide

the cover over the center conductor of the triax cable.

6. Insert the stripped center conductor through the

hole in the body of the banana plug, then wrap the
wire around the plug body.

7. Screw on the plastic cover, and make certain the wire
is secure by gently pulling on the plug.

Red banana plug

2-4

SECTION 2

Operation

Cut

/

u’

cut

/

/

I_ 1” ----+I

(A) Cut off insulation with knife

Cut off cuter shield.

Insulation ever
inner shield

f

(6) Strip insulation off inner shield

(C) Twist inner shield then strip inner conductor.

Twist inner shield and center conductor together,

slip on plastic ccvar.

WARNING
Do not use coaxial cables and adapters be­cause hazardous voltage from guard sources
may be present on the cable shields.

Figure 2-5 shows the general instrument connections for
the discussions below. Note that DUT guarding or
shielding are not indicated here; see Figures 2-21 and 2-24
for shielding and guarding information. Also, 2-p&
switching for rows A-F is shown in the figures; GUARD
is not switched cm rows G and H. As shown, all figures
assume instruments are connected to rows, and the DUT
is connected to columns.

DMM Connections

General

(B), and (C). Floating connections are shown in (A), with
LO and HI routed to two separate jacks on the Model
7072~HV. The common LO connections in (B) should be
used only for non-critical applications because the per­formance of the GUARD pathway is not specified.

DMM connections are shown in Figure 2-5(A),

(D) Insert wire into hole and wrap around body.

(E) Screw on plastic cover.

Figure 2-4.

2.5.4

The following paragraphs discuss connecting the Model

7072~I-IV to various general dasses of instrumentation
such as DMMs, electrometers, sources, and source/
measure units. Because these configurations are generic
in nature, some modification of the connecting schemes
may be necessary for your particular instrumentation.
Also, special cables or adapters may be necessary. In all
cases, 3-lug triax cables must be used to make the ccmnec-

tions.

Triaxid Cable Preparation

General Instrument Connections

WARNING
Hazardous voltage from other guard sources
may be present on LO or the DUT if other

crosspoints are closed.

4-wire DMM connections are shown in Figure 2-50 In

this case, a total of four jacks are required; HI, LO, SENSE
HI, and SENSE LO.

Electrometer Connections
Typical electrometer connections are shown in Figure

2-5(D) through (G). The unguarded volts connections in

(D) show the HI signal path routed through one jack, and
the LO path goes through the other connector. Both
GUARD pathways are connected to electrometer LO. For

guarded voltage (E), Model 7072~HV GUARD is con-

nected to electrometer GUARD.

The connections for electrometer fast amps and resis-

tance measurements are shown in Figures 2-5(F) and (G).

These configurations are essentially the same as those

discussed above. For the case of fast amps, both GUARD

paths are connected to electrometer LO, while in the case

of guarded resistance, one GUARD path is connected to

electmmeter GUARD, and

nected to electrometer LO.

the other

GUARD path is con-

2-5

SECTION 2
Overation

Source Connections
Voltage and current source connections are shown in Fig-

ures 2-5(H) through (J). The HI and LO paths of the vclt­age source (H) are routed through two jacks, with both
card GUARD pathways connected to voltage source LO.
For the unguarded current source connections (I), card
GUARD is again connected to source LO, with source HI
and LO routed through two pathways. In the case of the
guarded current source in 0, card GUARD of the Hl sig­nal path is connected to souxe GUARD, and the other

GUARD path is connected to sauce LO.

ROWS

Source/Measure Unit Connections

Figure 2-50) shows typical connections for a source/
measure unit (SMW. In this instance, a remote-sensing
type of a SMU is shown, requiring a total of four signal
pathways to the DUT. For critical measurements, both
source and sense HI pathways would be guarded as
shown, with two of the four card GUARD pathways con­nected to SMU GUARD terminals. As with other instm­ment connections, the LO card GUARD pathways are

connected to SMU LO terminals.

COLUMNS

Fipre 2-5.

A.) DMM Floating

ROW COLUMN

Warning : Hazardous voltage from guard

sources may be present on LO.

S.) DMM Common LO

General Instrument Connections (A-B)

L-----l

707.2.HV

707%HV

DUT

Note : Use this configuration only for

noncritical measurements.

2-6

SECTION 2

Operation

C.) DMM 4.Wire

ROWS

COLUMNS

L-----l

7072.HV

General

Instrument

Electrometer

D.) Electrometer, Unguarded Volts

Connections (C-D)

ROWS

COLUMNS

L----A

7072.HV

2-7

SECTION 2
Otleration

ROWS

Electrometer

E.) Electrometer, Guarded Volts

ROWS

_---__

r----i

COLUMNS

DUT

707%HV

COLUMNS

I

Electrometer

F.) Electrometer. Fast Current

i

G.) Electrometer. Resistance (Guarded)

GlWd

Electrometer

I

HI

LO

ROWS

7072.HV

r---_~

7072.HV

COLUMNS

DUl

General Instrument Connections (E-G)

243

SECTION 2

Operation

H.) Voltage Source

ROWS

ROWS COLUMNS

r-----7

L----A

7072.HV

COLUMNS

I.) Current Source, Unguarded

ROWS

J.) Current Source. Guarded

L-----l

7072.HV

_ - - - - -

L----A

707BHV

COLUMNS

DUT

2-9

SECl7ON 2
Operation

H

Force C”*n
IorV

r-

sense -..-.-

Vorl

Source/Measure

ROWS COLUMNS

K.) Source/Measure Unit

Notes : 1.) DUT shielding/guarding not shown. See figures Z-21 and2.24

~enerai Instrument Connections (K)

-7-J. AZ-+-

L-----l

7072-H”

2.) Z-Pole switching for rows A-F shown. GUARD is not witched
on rows G and H.

2-10

SECTION 2

Operation

2.5.5

Keithley Instrument Connections

The following paragraphs outline connecting typical
Keithley instruments to the Model 7072~HV Semicon­ductor Matrix Card. Other similar instruments can be

connected using the same cabling as long as their input/
output configurations are the same. Instrument connec­tions covered include:

. Model 617 Electrometer/Source
. Model 196 DMM
. Model 230 I’rogrammable Voltage Source
. Model 220 Programmable Current Source

. Model 590 CV Analyzer
. Model 236/237/238 Source Measure Unit

Model 617 Electrometer Connections
ConnectionsfortheModel617Electrometerareshownin

Figure 2-6. The electrometer INPUT should be connected

only to rows A and B for currents less than 2nA; other­wise, current offset will affect measurement accuracy.

1. Connect one end of a Model 7078-TIW-3 or -10 3-lug
triaxial cable to rcw A of the Model 7072-HV.

2. Connect the other end of the triax cable to the Model
617 INPUT connector using a Model 6172 adapter.

3. Connect the trlax end of a prepared triax/banana ca­ble to row B of the Model 7072XV.

4.

Connect the banana plug end of the triax/banana ca­ble to the COM terminal of the Model 617. The short­ing link between COM and chassis ground should be

removed for this application.

5.

Place the GUARD switch in the OFF position.

6. To connect the voltage source to the Model 7072~HV,
connect the V-SOURCE HI and LO connectors of the
Model 617 to the desired row connectors on the ma­trix card. Figure 2-6 shows connections to rows C
and D.

I

Guard off --._I

Voltage Source 1
Connection

Model 617

t

Triax/Sanana Cables

(See Figure 2 - 4)

Figure 2-6. Model 617 Electrometer Connections

7078 - TRX Triax

@I

A

7072.HV Matrix Card

SECllON 2

Operation

Model 196 DMM Connections

Cquwct the Model 196 or other similar DMM to the ma­trix card using the general configuration shown in Figure
2-7. The VOLTS OHMS HI and LO terminals should be
connected to the desired rows using the prepared triax/
banana cables discussed above. For 4-wire ohms meas­urements, the OHMS SENSE HI and LO terminals
should be connected to two additional rows using the
same type of cables.

NOTE
For low-level voltage measurements, connect
the inner shield of the HI cable to VOLT
OHMS LO to minimize noise.

Model 230 Voltage Source Connections
Connect the Model 230 OUTPUT and COMMON tenni-

nals to the desired rows using the prepared triax/banana
plug cables, as shown in Figure 2-8. For remote sensing

applications, the SENSE OUTPUT and SENSE COM­MON connectors can be routed through two additional
rows using similar cables.

Model 590 CV Analyzer Connections
The Model 590 CV Analyzer should be connected to rows

G and H (CV rows), or any column as shown in Figure

2-9. The BNC cables that are supplied with the Model 590

can be used; however, Model 7078-TRX-BNC triax-to­BNC adapters must be used at the Model 707%HV end.

‘igure 2-7.

2-12

(See Figure 2 - 1)

196 DMM

Inner Shield (Connect to LO -

for Low-Level Measurements)

7072WJ Matrix Card

Model 196 Dh4M Connections

Common

SECTION 2

Operation

Figure 2-8.

230 Voltage Source

7072-HV Matrix Card

Model 230 Voltage Source Connections

Z-13

SECTION 2

Operation

Note : Connect CV Analyzer to

Rows G and H, or any
column (use G and H
pathways for optimum
performance).

Figure 2-9. Model 590 CVAnalyzer Connections

Model 220 Current Source Connections

The Model 220 Current Source can be connected to the
matrix card using the Model 6167 Guarded Adapter, as
shown in Figure 2-10. This configuration guards the out­put signal to

minimize the effects of distributed capaci-

tance and leakage current.

NOTE
TheModel6167Adaptermust bemodified by
internally disconnecting the inner shield con­nection of the input jack from the
GUARDED/LJNGUARDEDselectionswitch.
Otherwise, instrument LO will be connected
to chassis ground through the adapter.

Triax-to-BNC

Adapters

7072-HV

Matrix Card

3. Connect the Model 220 GUARD output to GUARD
INPUT terminal of the adapter.

4. Connect the triax end of a triax/banana cable to the
desired row on the Model 7072~HV.

5. Connect the banana plug end of the triax/banana ca-

ble to the OUTPUT COMMON jack of the Model

220.

Model 236/237/238 Source Measure Unit Connections

Sourcemeasureunits are connected to the matrix card us­ing Model 7078.TRX cables. A Model 237;BAN-3 Triaxl

Banana cable can also be used to connect the output low

binding post on the source measure unit to the matrix.

2.5.6

Typical Test Fixture Connections

1. Connect the Model 6167 adapter to the Model 220
OUTPUT jack.

2. Connect a Model 7078-TRX-3 or -10 triax cable be­tween the guarded adapter and the desired row of
the Model 7072~HV.

2-14

Typically, one or more test fixtures will be connected to
desired columns of the Model 7072~HV. Typically, the
test fixtures will be equipped with card-edge connectors
with wires soldered to them. In some cases, the test fix­ture will be equipped with trlax connectors; for those

Use Rows A and B when

Sourcing < 2nA

SECTION 2

OptTL?ti0Fl

II

Guarded Adapter -

Connect GUARD OU?

to GUARD

Figure 2-10. Model 220 Current Source Connections

7078.TRX Triax

IF-l

7072-HV Matrix Card

types, Keithley Model 7078-TRX-3 or -10 cables can be
used, as shown in Figure Z-11.

WARNING

Do not use BNC cables and adapters in cases

where hazardous voltages from guard
s.ource~ could be present on the BNC cable
shields.

Internally, the test fixture should be wired as shown in

the equivalent circuit of Figure Z-12. SIGNAL should be

connected to the probe or other device contact points,
while GUARD should be carried through as close to the
device as possible. If coaxial probes are to be used, con­nect GUARD to the probe shield if the probe shield is in­sulated from the fixture shield.

Usually, the chassis ground terminal of the triax connec­tor will automatically make contact with the fixture
shield by virtue of the mounting method. However,
ground integrity should be checked to ensure continued

protection against hazardous guard voltages.

2-15

SECTION 2
Operation

3 - Lug Female
Triax Connectors
(or run cables through strain
reliefs and connect internally)

Note : Teflon@ - insulated connectors

recommended for specified

performance.

Warning : Do not use BNC cO”“ectorS

to avoid possible shock

hazard.

3gure 2-11.

Figure Z-12.

7072-HV Matrix Card

Typical Test Fixture Connections

From

7072-HV

CWd

Equivalent Circuit of Test Fixture

Triw Cable

Co?tne~tiofts

Chassis 1
Ground L

-----

1

Wafer

--_--_--- _I
Test Fixture Chassis

2-16

SECTION2

Operation

2.6 MATRIX CONFIGURATION

The following paragraphs discuss the switching matrix
of the Model 707’2~HV as well as how to expand the ma­trix by connecting two or more cards together.

2.6.1

As showninFigureZ-13, theMode170724Visorganized
as an 8 x 12 (eight row by 12 column) matrix. The rows are
labeled A through H, while the columns on the card are
numbered 1 through 12. The actual column number to
use when programming depends on the slot and unit
number, as summarized in Table 2-3. For example, card

Switching Matrix

column number 2 on a card in slot 5 of unit 1 is accessed as
matrix column 62.

Each intersecting point in the matrixis called a crosspoint
that can be individually closed or opened by program­ming the Model 707 mainframe. The crosspoints for rows
A through F are configured for 2-pole switching, as
shown in Figure 2-13. For these rows, SIGNAL and
GUARD are switched separately to any of the 12 columns
on the card.

The crosspoints for rows G and H use l-pole switching,
with only SIGNAL being switched. The equivalent cir­cuit for this arrangement is also shown in Figure 2-13.

1

Figure 2-13.

Model 7072-HVMatrix Organization

Crosspoint Switching

for Rows G and H.

Columns

1 - 12

2-17

SECTION 2
Operation

Table 2-3. Column Numbering by Slot and

Unit

Slot

1

2
3
4
5
6

1 73-84
2 85-96
3 97-108
4
5
6

1 145-156
2

3
4 181-192
5 193-204
6

1
2 229-240
3 241-252
4 253-264
5 265276
6 277288

1
2
3
4
5
6

-

2.6.2

In order to maintain the integrity of the low-current and
CV pathways, isolator relays are incorporated into each
column. These isolators are indicated as small circles on
the matrix diagram of Figure 2-13. Each relay remains
open until a crosspoint located in rows C through H is to
be closed. In this manner, the general-purpose pathways
are isolated from the more critical low-current and CV
pathways.

Row and Column Isolators

columns (l-12)

l-12
13-24
25-36
37-48
49-60
61-72

109-120
121-132
133-144

157-168
169-180

205-216

217.228

289-300
301312
313-324
325-336
337-348
349-360

The column isolator relay between rows B and C for a
given column will not close if a row A or B crosspoint in
that column is closed. This feature helps to prevent acci­dental application of high voltage to rows C through H.

In a similar manner, row isolator relays isolate the cross­point relays from a given row to minimize leakage cur­rent and capacitance, and maximize path resistance. The
row isolator relay closes when any crosspoint relay asso­ciated with that row is closed.

2.6.3

As discussed previously, the eight rows on the matrix
card are designed for different purposes. Rows A and B
are designated low-current, high voltage rows, rows C
through F are general purpose rows, and rows G and H
are cv rows.

Many of the specifications for the card differ among row
types. For example, the offset current for the low-current
rows is <IpA, but the general purpose and CV rows have
a higher offset current of 20pA. Thus, A and B would be
the rows of choice for low-current measurements. The
path isolation for rows A and B is an order of magnitude
higher than that the other rows (10% vs. 10’2fL). These
two rows would be preferable for very high-impedance
measurements. Rows A and B are also used for voltage
levels up to 1300v.

In summary, the following general rules apply when
choosing which rows to use for specific measurements:

l Use rows A and B for low-current and/or high voltage

measurements.

l Use rows A, B, G, and H for low-capacitance measure-

ments.

l Rows A and B should be used where high path isola-

tion resistance is of primary concern.

l Rows C through F have the largest bandwidth, while

rows G and H have the smallest bandwidth.

For more detailed information on these factors, refer to
the Model 7072~HV Specifications located at the front of
this manual.

Pathway Considerations

2-18

Note : Rows C - F jumpered through backplane.

ROWS A, B, G, and H require installation of coaxial jumpers (shown heavily shaded).

I

Figure 2-14. Connecting Three Cards

for

8 x 36 Matrix

SECTION 2

Operation

2.6.4

Two to six Model 7072-HV cards can be connected to-

gether within the mainframe to yield an 8 x N matrix,
where N depends on the number of cards. Figure 2-14
shows an internally expanded matrix with three cards,
resulting in an 8 x 36 (eight row by 36 column) matrix. As
s-arizedinTable2-3,the actualcolumnnumberused
when programming the unit is determined by the slot.

Rows C through F are automatically connected together
through the backplane of the mainframe. The mainframe
can be configured for two sets of three cards each by re­moving jumpers from the backplane of the mainframe;
see Section 3 of the Model 707 Instruction Manual for de­tails on removing the jumpers. With the row jumpers re­moved, rows C through F of Model 7072~HV cards in
slots 1 through 3 are connected, and rows C through F of
Model 7072~HV cards in slots 4 through 6 are connected
together.

Because of more critical signal paths, rows A, B, G, and H

are not jumpered through the backplane. Instead, you
must install the supplied coaxial jumpers between appro­priate connectors on Model 7072~HV cards (for critical
signal paths, rows can be isolated from other cards by not
installing these cables). Each card has two coaxial connec­tors for each row, allowing daisy chaining of card rows.
These connectors can be reached by lifting the access
door on the top of the mainframe; it is not necessary tore-

Internal Matrix Expansion

move cards to install the jumpers. Figure 2-15 shows an
edge-on view of the jumper connectors with row nun­bers marked for convenience. Figure 2-16 demonstrates
how three cards can be daisy chained together using the
coaxial jumpers.

WARNING
The shells of the row jumpers are at guard
potential. To avoid a possible shock hazard,

always disconnect all cables from the row
andcolumn jacksbeforeremovingorinstall­ing jumpers.

2-19

SECTION 2
Operation

Figure 2-16.

2.6.5

External jumper cables must be used to expand the num-

her of rows in the matrix, or to connect between columns

of cards installed in different mainframes. An example of
such an expanded matrix is shown in Figure Z-17. Here,

six cards are configured as a 16 x 36 matrix. Since the rows
are internally jumpered, only columns must be jumpered
externally in this config~~ration. Note that the backplane

7’hree Cards in Daisy Chain Configuration

External Matrix Expansion

jumpers must be removed to separate the cards into two
*CUPS.

Trim tee adapters (Model 7078-TIU-T) can be used to
provide daisy chain capability between the triax input

connectors. Figure Z-18 shows a typical arrangement be-

tween two Model 70724-W cards. Ideally, custom-length
biax cables should be used to avoid the cable “jungle”
that would occur with longer, standard-length cables.

Z-20

SECTION 2

Operation

Figure 2-17.

16 x 36 Matrix Constructed by External Jumpering

2-21

SECTION 2
Operation

Triax Tee
AdaDters

Matrix

Input/Output

Figure 2-18.

Using Trim Tee Adapters to Daisy Chain Cards

2-22

SECTION 2

Operation

2.7 MEASUREMENT CONSIDERATIONS

Many measurements made with the Model 7072-HV con­cern low-level signals. Such measurements are subject to
various types of noise that can seriously affect low-level
measurement accuracy. The following paragraphs dis­cuss possible noise sources that might affect these mea­surements.

2.7.1 Magnetic Fields

When a conductor cuts through magnetic lines of force, a
very small current is generated. This phenomenon will fre­quently cause unwanted signals to occur in the test leads of
a switching matrix system. If the conductor has sufÞcient
length, even weak magnetic Þelds like those of the earth
can create sufÞcient signals to affect low-level measure­ments.

Two ways to reduce these effects are: (1) reduce the
lengths of the test leads, and (2) minimize the exposed
circuit area. In extreme cases, magnetic shielding may be
required. Special metal with high permeability at low
ßux densities (such as mu metal) are effective at reducing
these effects.

Even when the conductor is stationary, magnetically
induced signals may still be a problem. Fields can be pro­duced by various signals such as the AC power line volt­age. Large inductors such as power transformers can
generate substantial mangetic Þelds, so care must be
taken to keep the switching and measuring circuits a
good distance away from these potential noise sources.

2.7.2 ELECTROMAGNETIC INTERFERENCE
(EMI)

• impulse sources as in the case of arcing in high-volt­age environments

The effect on instrument performance can be considerable
if enough of the unwanted signal is present. A common
problem is the rectiÞcation by semiconductor junctions of
RF picked up by the leads.

The equipment and signal leads should be kept as far
away as possible from any EMI sources. Additional
shielding of the measuring instrument, signal leads, and
sources will often reduce EMI to an acceptable level. In ex­treme cases, a specially constructed screen room may be
required to sufÞciently attenuate the troublesome signal.

Many instruments incorporate internal Þltering that may
help to reduce RFI effects in some situations. In some cases,
external Þltering may also be required. Such Þltering, how­ever, may have detrimental effects on the desired signal.

2.7.3 Ground Loops

When two or more instruments are connected together,
care must be taken to avoid unwanted signals caused by
ground loops. Ground loops usually occure when sensi­tive instrumentation is connected to other instrumenta­tion with more than one signal return path such as power
line ground. As shown in Figure 2-19, the resulting
ground loop causes current to ßow through the instru­ment LO signal leads and then back through power line
ground. This circulating current develops a small but un­desirable voltage between the LO terminals of the two in­struments. This voltage will be added to the source
voltage, affecting the accuracy of the measurement.

The electromagnetic interference characteristics of the
Model 7072-HV Semiconductor Matrix Card comply with
the electromagnetic compatibility (EMC) requirements of
the European Union as denoted by the CE mark. Howev­er, it is still possible for sensitive measurements to be af­fected by external sources. In these instances, special
precautions may be required in the measurement setup.

Sources of EMI include:

• radio and television broadcast transmitters

• communications transmitters, including cellular
phones and handheld radios

• devices incorporating microprocessors and high
speed digital circuits

SIGNAL LEADS

INSTRUMENT 1

GROUND

CURRENT

INSTRUMENT 2

LOOP

POWER LINE GROUND

INSTRUMENT 3

Figure 2-19. Power Line Ground Loops

Figure 2-20 shows how to connect several instruments to­gether to eliminate this type of ground loop problem.

2-23

SECTION 2
Operation

Here, only one instrument is connected to power line
ground.

INSTRUMENT 1

‘igure Z-20.

INSTRUMENT 2

0

0 0

1 1

POWER LlNE GROUNrJ

T

Eliminating Ground Loops

INSTRUMENT

lo

1

3

Ground loops are not normally a problem with instm­mats having isolated LO terminals. However, all instm­mats in the test setup may not be designed in this man­ner. When in doubt, consult the manual for each instru­ment in the test setup.

2.7.5

Noise Currents Caused by Cable
Flexing

Noise currents can be generated by bending or flexing co­axialortriaxialcables. Suchcurrents, whichareknownas
triboelectxic currents, are generated by charges created
between a conductor and insulator caused by friction.

Low-noise cable can be used to minimize these effects.
Such cable has a special graphite coating under the shield
to provide lubrication and to provide a conduction path
to equalize charges.

Even low-noise cable generates some noise currents
when flexed or subjected to vibration. To miniie these
effects, keep the cables as short as possible, and do not
subject them to temperature variations that could cause
expansion or contraction. Tie down offending cables se­curely to avoid movement, and isolate or remove vibra­tion sources such as motors or pumps.

2.7.6 Shielding

2.7.4 Keeping Connectors Clean

As is the case with any high-resistance device, the integ­rity of triaxial and other connectors can be damaged if
they are not handled properly. If the connector insulation
becomes contaminated, the insulation resistance will be
substantially reduced, affecting high-impedance meas­urement paths.

Oils and salts from the skin can contaminate connector
insulators, reducing their resistance. Also, contaminants
present in the air can be deposited on the insulator sur­face. To avoid these problems, never touch the connector
insulating material. In addition, the matrix card should
be used only in clean, dry environments to avoid con­tamination.

If the connector insulators should become contaminated,
either by inadvertent touching, or from air-borne depos­its, they can be cleaned with a cotton swab dipped in
clean methanol. After thorough cleaning, they should be
allowed to dry for several hours in a low-humidity envi­ronment before use, or they can be dried more quicklyus­ing dry nitrogen.

Proper shielding of all unguarded signal paths and de­vices under test is important to minimize noise pickup in
virtually any switching matrix system. Otherwise, inter­ference from such noise sources as line frequency and RF
fields can seriously corrupt a measurement.

In order for shielding to be effective, the shield surround­ing the HI signal path should be connected to signal LO
(or chassis ground for instruments without isolated LO
terminals). Since most Model 7072~HV matrix applica­tions call for separately switching LO, a separate connec­tion from LO to the cable shield at the source or measure­ment end must be provided, as in the example of Figure

2-21. Here, we are using the GUARD path of the Model

7072-HV to carry the shield out to the device under test.
Needless to say, this arrangement should not be used
with guarding, as GUARD and LO should not be con­nected together.

WARNING

Hazardous voltage may be present if LO on

any instrument is floated above ground po-

tential.

If the device under test is to be shielded, the shield should
be connected to the LO terminal. If you are using the
GUARD connection as shield, care should be taken to in-

2-24

SECTION 2

Operation

sulate the outer ring of the hiaxial connector mounted on
the test fixhm from the test fixture itself. Otherwise, LO
will be connected to chassis ground, possibly resulting in
a ground loop. An alternative is to use two shields, one
mounted within kind insulated from) the other. In this
case, the GUARD path would be connected to the inner

Inner Shield
CO me&d to LO

of

HI Triax

r----

shield, while the outer shield would be chassis grounded.
This arrangement is shown in Figure Z-22. Incidentally,

this configumtion is also recommended for guarded ap­plications, with the inner shield as guard, and the outer
shield acting as a safety shield.

------

Figure 2-21.

7072TpH” (Jq5

F&m 2-22.

Shielding Example

Dual ShieZd Test Fixture

7072-HV Card

r----------i

---

l---------l

I

L - - - - - - - - - - AC Outer Shield

I

(Chassis Ground)

2-25

SECTION 2

Operation

Inner Shield

Measuring

Instrument

L-i--J

DUT

Figure 2-23. Guarded Circuit

2.7.7

Guarding is important in high-impedance circuits where
leakage resistance and capacitance could have degrading
effects on the measurement. Guarding consists of using a
shield surroumliig a conductor that is carrying the high­impedance signal. This shield is driven by a low-imped­ance amplifier to maintain the shield at signal potential.
For biaxial cables, the inner shield is used as guard.

Guarding minimizes leakage resistance effects by driv­ing the cable shield with a unity gain amplifier, as shown
in Figure 2-23. Since the amplifier has a high input im­pedance, it minimizes loading on the high-impedance
signal lead. Also, the low output impedance ensures that
the shield remains at signal potential, so that virhmlly no
leakage current flows through the leakage resistance, RL.
Leakage between inner and outer shields may be consid­erable, but that leakage is of little consequence because
that current is supplied by the buffer amplifier rather
than the signal itself.

Guarding

In a similar manner, guarding also reduces the effective

cable capacitance, resulting in much faster measure­ments on high-impedance circuits. Because any distrib­uted capacitance is charged through the low impedance
of the buffer amplifier rather than by the source, settling
times are shortened considerably by guarding.

In order to use guarding effectively with the Model
707%HV, the GUARD path of the matrix card should be
connected to the guard output of the sourcing or measur­ing instrument. Figure 2-24 shows typical connections.
Guard should be properly carried through the inner
shield to the device under test to be completely effective.
The shielded, guarded test fixture arrangement shown in
Figure 2-22 is recommended for safety purposes (guard
voltage may be hazardous with some instruments). With
most instruments, special adapters or cables may be re­quired to connect guard to the inner shield, and at the
same time route signal LO through a separate cable.

2-26

------

SECTION 2

Operation

COLUMNS

7072-HV Card

‘igure 2-24. Typical Guarded Signal Connections

2.7.8

Matrix Expansion Effects on Card
Specifications

Specifications such as those given for path isolation and
offset current are with a single Model 7072-HV Card in-

stalled in the mainframe. Expanding the matrix by inter­nally or externally connecting two or more Model
7072~HV Cards together will degrade system perform­ance specifications (other types of cards do not affect the
specifications because they use different pathways in the
mainframe backplane). The extent depends on how

Warning : Outer fixture must be

used to avoid possible

shock hazard from guard.

many cards are used, as well as the amount of cabling
used to connect them together.

With internal row expansion, isolation among rows is de­creased, and offset current is increased, although the iso­lator relays on the card do help to minimize these effects.
With external row or column expansion, isolation and
offset current specifications are degraded because of the
additional parallel paths and relays present on each sig­nal line.

2-27

SECTION 3

Applications

3.1 INTRODUCTION

This section covers typical applications for the Model

7072~HV Semiconductor Matrix card and is organized as
follows:

3.2 CV Measurements: Outlines the test configuration
and procedure for making quasistatic and high-fre­quency cv measurements.

3.3 Semiconductor Test Matrix Details a semiconduc­tor test matrix that can be used to perform a variety of dif­ferent tests on semiconductors such as FETs.

3.4 Resistivity Measurements: Covers methods to
measure the resistivity of semiconductor samples using
the van der l’auw method.

3.5 Semiconductor Parameter Analysis: Discusses us­ing the Model 7072~HV in conjunction with an HP 4145B
Semiconductor Parameter Analyzer.

3.2 CV MEASUREMENTS

The Model 707’2~HV can be used in conjunction the Keith­ley Model 590 CV Analyzer, and the Keithley Model 595
Quasistatic CV Meter to perform quasistatic and high­frequency CV (capacitance vs. voltage) tests on semicon­ductors. The resulting CV curves can be used to calculate
important semiconductor parameters such as doping

profile, band bending, and mobile ion concentration.

3.2.1

The stand alone system shown in Figure 3-l can be used

to make CV measurements without the aid of a corn-

Stand Alone System Configuration

puter. System components perform the following fmc-

tiOllS.

Model 590 CV Analyzer: Measures CV data at 1OOkHz
and 1MI-k and sends the resulting data to the plotter for

graphing.

Model 595 Quasistatic CV Meter: Measures quasistatic

CV data and sends the data to the plotter for graphing in

real time.

Model 707 Switching Matrix: Controls the semiconduc­tor matrix card to close and open the desired crosspoints
at the proper time.

Model 7072~HV Semiconductor Matrix Card: Switches
the signal pathways to the six wafers under test.

HP-GL Plotter: Plois CV and other curves directly from
the Models 590 and 595.

3.2.2 Computerized System
Configuration

Figure 3-2 shows a computerized version of the CV ma­trix test system. The addition of a computer allows
greater system versatility and easier instrument control.
Also, analysis functions such as doping profile and ion
concentration canbe added to the software to expand CV
analysis capabiities.

3-l

SECTION 3

Applications

Wafers Under

Test

6

IB
‘0

ID
IE

IF

IG

Note : Rows C-F can be used

r

for this signal path.

Model 595

Quasistatic CV Meter

-IT--

,

. ^ I

,

I

HP-GL

3-2

Wafers Under

Test

SECTlON 3

Applications

Note : Rows C-F can be used for

this signal path.

1 2

I
I

I

L--------

3 4 5 6 7 8 9 10 11 12’

7072-HV Matrix Card

707 Switching Matrix

r

Model 595

Computer

P

I

7051

I

BNC

Cables

IEEE-488 Bus

I

0

Input

Model 590

CV Analyzer

I

I

Figure 3-2.

Note : Remove jumpers to other 7072.HV cards (if installed)

to optimize Model 595 measurement accuracy.

Computerized CV System Configuration

3-3

SECTION 3
Applications

3.2.3 Optimizing CV Measurement
Accuracy

For accurate CV measurements, each Model 590 CV
measurement pathway must be cable corrected using the

procedure outlined in the Model 590 Instruction Manual.
The pathways to each DUT must be cable corrected sepa­rately.

Also, for best quasistatic CV results, the corrected capaci-

tance feature of the Model 595 should be used. Corrected

capacitance compensates for any leakage currents pre­sent in the cables, switching matrix, or test fixture. How­ever, care must be taken when using corrected capaci-

tance to ensure that the device remains in equilibrium

throughout the test sweep to avoid distorting the CV

curves.

In order to minimize the effects of the switching network
on quasistatic CV measurements, cables to the Model 595
and DUT should be kept as short as possible. Also, the
low-current pathways (rows A and B) should be used
with the Model 595.

3.2.4 Basic CV Test Procedure

The fundamental CV test procedure is outlined below.
Keep in mind that this procedure does not address many
considerations and aspects of CV testing, which is fairly
complex. The procedure given is for the stand alone sys­tem in Figure 3-1. Detailed inshument operating infor-

mation may be found in the pertinent instruction manu-

als.

1. Connect the HP-GL plotter to the IEEE-488 bus con­nector of the Model 595 only.

2. Set up the Model 595 for the expected CV sweep.

3. Close the crosspoints necessary to connect the Model

595 to the device under test, as summarized in Table

3-l. For example, to test device #l, close Al and BZ.

4. Place the probes down on the wafer test dots.

5. Run a quasistatic sweep on the selected device and
generate a CV curve.

6. Open the crosspoints that are presently closed.

7. Set up the Model 590 for the expected CV sweep.

8. Close the crosspoints necessary to connect the Model
590 to the device under test. For example, to test de­vice #I, close Gl and H2.

9. Run a high-frequency test sweep on the device to
store the CV data in the Model 590 buffer.

10. Disconnect the plotter from the Model 595 and con­nect it to the Model 590.

11. Generate a plot from the data in the Model 590
buffer.

12. Repeat steps 2 through 11 for the remaining devices,
as required.

Table 3-l. CV Test Crosspoint Summary

Closed Crosspoints

Wafer # Quasistatic 695) 1 High Frequency (590)

1
2
3

I I

4
5
6

3.2.5

Figures 3-3 and 3-4 show typical CV -es as generated
by the Models 595 and 590 respectively. The quasistatic
curve shows a fair amount of symmetry, while the the
high-frequency curve is highly asymmetrical. The asym­metrical nature of the high-frequency -e results from
the inability of the minority carriers to follow the high­frequency test signal.

Al, B2

A3,B4
A5, B6
A7,B8

A9, B10

All, 812 Gil, H12

Typical CV Curves

Gl, HZ
G3, H4
G5. H6
G7; H8

G9, HlO

3-4

SECTION 3
Applications

+0.4E-10 +0.4E-10

Figure 3-3.

-005.00

Typical Quasistatic CV Curve Generated by Model 595

+005.00

KEITHLEY 595

3-5

SECTION 3
Applicutions

0.90

- 4.99 - 3.99 - 2.99 - 1.99 - 0.99 0.00 1.00 1.99 2.99 3.99 4.99

Keithley 590: oo:w:1o:sno 1ooKHz x1 mer - Parallel

Figure 34.

Typical High-frequency CV Curve Generated by Model 590

3.3 SEMICONDUCTOR TEST MATRIX

Two important advantages of a matrix switching system

are the ability to connect a variety instruments to the de-

vice or devices under test, as well as the ability to connect

any instrument terminal to any device test node. The fol­lowing paragraphs discuss a typical semiconductor ma­trix test system and how to we that system to perform a
typical test: common-source characteristic testing of a
typical JFET.

3.3.1 System Configuration

Figure 3-5 shows the configuration for a typical multi-

purpose semiconductor test matrix. Instruments in the
system perform the following functions.

Bias (Volt) X 1 Oh+00

TheDC voltage source can supply a maximum of *lOOV

at clxrents up to 2mA.

Model 230 Voltage Source: Sources DC voltages up to
3201v at a maximum current of lOOm.4.

Model 590 CV Analyzer: Adds CV sweep measurement

capability to the system.

Model 220 Current Source: Used to source currents up to
a maximum of 1OlmA with a maximum compliance volt­age of 105V.

Model 617 Electrometer/Source: Measures current, and
also could be used to measure voltages up to tiOOVDC.

3-6

Model 196 DMM: Measure DC voltages in the range of

1OOnV to 300V. The Model 196 could also be used to

measure resistance in certain applications.

Device Under Test

SECTION 3

AppIications

SGSG SGSG

------------

12 3 4 5 6 7

7072-HV

707 Switching

SGSGSGSGSG

8 9101112

Matrix

Card

Matrix

Figure 3-5. Semiconductor Test Matrix

Device Under Test: A
such devices as bipolar transistors and FETs. Additional

connections could easily be added to test more complex
devices, as required.

3.3.2

Testing Common-Source Charac-

three-terminal fixture

for testing

teristic of FETs

ThesystemshowninFigure3-5couldbeused totestava-

riety of characteristics including
Vos[om. To demonstrate a practical use for the system, we

IGSS,

IOIO~I, IG[ONI, Im and

will show how it can be used to generate common source

characteristic curves of a particular JFET.

In order to generate these curves, the instruments must
be connected to the JFET under test, as shown in Figure
3-6. The advantage of using the matrix is, of course, that it
is a simple matter of closing specific crosspoints. The
crosspoints that must be closed are also indicated on the

diagram.

3-7

SECTION 3
Applications

o-

HI

0

LO

Model 230

Voltage Source

617

Electrometer/Source

_, .., . .

0 HI

Voltage
SOUW?

0 LO

@ = Closed Crosspoints on 7072-HV Card (Figure 3.5).

Figure 3-6. System Configuration

for

Measuring Common-Emitter Characteristics

Tonm the test,Vcsisset tospecificvalues, for example in
increments of 0.25V. At each Vcs value, the drain-source
voltage (VIE) is stepped across the desired range, and the

drain current, IO, is measured at each value of VOS. Once

all data are compiled, it is a simple matter to generate the

common-source

in Figure 3-7. If the

IV curves, an example of which is shown

system

is connected to a computer, the

test and graphing could all be done automatically.

3.4 RESISTIVITY MEASUREMENTS

TheMode17072-~HighVoltageSemiconductorMahix
card can be used in conjunction with a Model 220 Current
Source and a Model 196 DMh4 to perform resistivity
measurements on semiconductors. Such measurements
can yield such important information as doping concen­tration.

Figure 3-7. Typical Common-Source FET IV Charac-

teristics

3-8

SECTION 3

Applications

3.4.1

Figure 3-8 shows the basic test configuration to make
resistivity measurements on van der Pauw samples. The
Model 220 sources current through the samples, while

the Model 196 measures the voltage developed across the

samples. The matrix card, of course, switches the signal

Test Configuration

SGSGSGSGSGSGSGSGSGSGC”“”

_---------

paths as necessary. In order to minimize sample loading,
which will reduce accuracy, the Model 196 DMM should
be used only on the 300mV or 3V ranges. Also, this con­figuration is not recommended for resistance measure­mats above 1M due to the accuracy-degrading effects of
DMM loading.

1 2 3 4 5 6 7 8 9 101112

7072-HV Matrix Card

707 Switching Matrix

Fi,qure 3-8. Resistivity Test Confi,quration

3-9

SECTION 3
Applications

3.4.2

InordertomakevanderPauwresistivitymeasurements,
four terminals of a sample of arbitrary shape are
ured. A current (from the Model 220) is applied to two
terminals, while the voltage is measured (by the Model

196) across the two opposite terminals, as shown in Fig­ure 3-9. A total of eight such measurements on each sam­ple are required, with each possible terminal and current

Test Procedure

meas-

Table 3-2. Crosspoint Summary for Resistivity Measurements

I

Voltage

VI
VZ
V3
V4
VS
V6
V7
V8

Crosspoint

Sample #l 1 Sample #2

Al 84 E3 F2
A4 Bl E3 F2
A4 83 FL2 Fl
A3 84 E2 Fl
A3 B2 El F4
A2 B3 El F4
A2 Bl E4 F3
Al B2 E4 F3

A5 B9 E7 F6 A9 812 El1 FIO l-2
A8 85 E7 F6 Al2 B9 El1 FlO
A8 87 E6 F.5 Al2 Bll El0 F9
A7 B8 E6 F5 All B12 El0 F9
A7 B6 E5 F8 All BlO E9 F12 34
A6 B7 E5 F8 A10 811 E9 F12
A6 B5 E8 F7 A10 B9 El2 Fll 4-l
A5 86 E8 I?7 A9 BlO El2 Fll l-4

L

Closed

convention. The resulting voltages are designated Vl
through V8.

In order to source cunent into and measure the voltage
across the sample, specific crosspoints must be closed.
Table 3-2 summarizes the crosspoints to close for each
voltage measurement on all three samples from the test
configuration shown in Figure 3-8.

Current Voltage

1 Sample #3

B&Well B&VeelI

2-l

2-3 4-l
3-2 41

4-3

1

3-4
3-4

l-2
l-2

2-3
2-3

3-10

SECTION 3
Applications

Fiaure 3-9.

1“

(0

Resisti& Measurement Conventions

3-11

SECTION 3
Applications

3.4.3

Once the eight voltage measuremenh are known, the
re+tivity can be calculated. Two values of resistivity, PA
and PB are initially computed as follows:

Whel-2:

Once PA and pi are known, the average resistivity, PAVG,
can be determined as folkxvs:

Flesistivity Calculations

1.1331 fA ts (vz+v~-vI -W

PA=

1.1331 fS tS (v6 +

pe =

PA and pi are the resistivities in R-cm

ts is the sample thickness in cm
VI through VS are the voltages measured by
the Model 196

I is the current through the sample in amperes

fA and fs are geometrical factors based on sam­ple symmetry cf.4 = fs = 1 for perfect sym­metry).

pAYG= pA+pB

I

VS

I

2

- v5 - v7)

3.5 Semiconductor IV Characterization

A source measure unit such as the Model 236 or 237 is
used to test and characterize many types of devices. One
of these is semiConductor devices. The following para-

graphs explain the basic scheme and connections used to
generate an IV curve of a bipolar or MOS transistor. Fig­ure 3-10 shows FET devices connected in a test fixture.

3.5.1 lest Configuration

Since rows A and B of the Model 7072-I-W can be used for
low-current and high voltage source or measure applica­tions,theyareusedtoswitchtheModel237SourceMeas-

me Unit. The Model 237 is capable of sourcing up to 1100
volts. If it will be sourcing more than 200 volts, it must be
connected to rows A and B only. The Model 236 is capable
of sourcing up to only 110 volts, so it may be connected to
any row.

At the test fixture, the drain and source leads of the FETs
are connected in a4-wire sensing configuration. This con­nection scheme allows the Model 237 to use remote sens­ing to accurately apply Vds to the FETs. The Model 236
uses local sensing and is used to supply the bias to the
gates of the FETs. Since the gates are low current, remote
sensing is not necessary.

If more DUT pins are needed, the system is easily ex­panded by adding more Model 7072-HV matrix cards.
Each additional card will add 12 columns to the system.

3.5.2 Cable Connections

Source Measure Unit and test fixture connections to the

matrix card are accomplished using Model 7078-TW.
These are three slot trim cables. On each Source Measure
Unit, the banana jack (5-way binding post) is used to ac­cess OUTPUT LO. This connection is made using a
Model 237-BAN. An equivalent to the Model 237-BAN-1

can be made using the information in Figure 2-4. This al-

lows OUTPUT LO to be applied to a signal pathway and

independently switched. The guard pathways of the ma-

trix cards are used exclusively to extend the driven
guards of the Source Measure Units to the DUT to elimi-

nate the effects of leakage current.

3.6 SEMICONDUCTOR PARAMETER ANALYSIS

One or more Model 7072-I-N Semiconductor Matrix
Cards can be used in conjunction with an HP4145B Semi­conductor Parameter Analyzer (SPA) to provide a versa­tile switching system capable of complete IX characteri­zation of semiconductors. The following paragraphs dis­cuss system configuration, connections using the
7078-CSHP Cable Set, and SPA measurement considera­tions.

3-12

SECTlON 3

Applications

GII I I I I I I I I I I
H

I I I I I I I I I I II

II I I 1 I I I I I

I’ ‘I\ ” ” ’

7072.HV

MATRIX CARD

Fkure

3-10. Multi Unit Test System Using Models 236 and 237 Source Measure Units

7072.HV

MATRIX CARD

3-13

SECTION 3
Applications

3.6.1

Figure 3-11 shows the general configuration of the SPA
switching system. The components of the system per-

form the following htnctions:

System Configuration

SMU 1

HP 41458

Semiconductor SMU 4

Parameter

Analyzer

SMU 2
SMU 3

Vsl
vs
Vml

2

HP 4145B: Has four SMUs (Source/Measure Units), two
voltage scnmes, and two voltage measurement ports.
The unit can automatically run a variety of tests on semi-

conductors and plot data on a built-in CRT.

Test

K

.1...12

t

Fixture

13...24

25...36.

1

1

A

1...12

13...24

p

25...36

1

I

1 7

072.HV
Card

Columns

>

r

+ LEE,466 Bus

System Controller

HP9000 or IBM PC/AT

Note : Connecting cables included in 707%CSHP cable set

SECTION 3
Applications

Model 707 Switching Matrix Controls the matrix card to
open and close signal paths as required.

Model 7072~HV Semiconductor Matrix Card: Switches

the test pathways to the deviceunder test. In this particw
lar application, three Model 707%HV cards provide
36pin test capability. A total of six cards can be installed
in a single mainframe, providing up to 72-pin capability
in one mainframe.

System Controller: Controls the SPA and switching ma-

trix with user-written software. Typical controllers for
thisappllcationareHP9000Series200 or300 (withHl-IB
interface), and IBM PC, AT or compatible computers
(equipped with an IEEE488 interface).

Test Fixture: Provides the interface between the device
under test and the matrix card. Typically, the test fixture
will be equipped with triax connectors for ease of connec­tions.

3.6.2

Figure 3-12 shows how to connect the HP 4145B to the
Model 7072-I-W using the optional Keithley Model
707%CSHP Cable Set. The four SMU ports are to be con­nected with the triax cables (7078-TRX-lo), while the two
voltage source and voltage measurement ports Ws and
Vm) are to be connected using BNC cables (7051-10) and
triax-BNC adapters (7078-TRX-BNC). Typically, the SPA
will be connected to the rows, as shown in Figure 3-12.

Connections to a user-supplied test fixture should be
made using t&x cables in order to maintain path integ­rity and safety. BNC cables and adapters should not be
used in case hazardous potential appears on guard terrni­nals.

Cable Connections

Any switching system can degrade low-level signals, and
the same holds true for the system shown in Figure 3-10.
Since rows A and B on the Model 7072~HV are dedicated
lowcurrentpathways,theSMUsthatwillsourceorsense
low-level signals should be connected only to these rows.
The remaining rows can be used for less-critical signals.

Safety considerations are also a concern when connecting
instruments to a switching matrix. Therefore, it is

strongly recommended that you carefully read the HP

41458 manual before using the system.

WARNING

Hazardous voltage may be present on the

outer conductors of the connecting cables
when the HP 41458 is set up for floating
measurements.

3.6.4 Typical Test Procedure

The following paragraphs outline the procedure for us­ing the SPA/matrix system to perform a typical test: Vos­IO (common-source) airves of a typical JFET. The proce­dure uses one of the four standard setups that are part of
the applications package supplied with the HP 4145B.

System Configuration

Figure 3-13 shows the configuration and connections for
this example. Only three of the four SMLIs are required
for the test, as indicated in the figure. A total of four FETs
can be connected to a single card, as shown on the dia­gram. In all cases, triax cabling should be used. The cross­points to close to test a specific FET are summarized in
Table 3-3.

Table 3-3.

Crosspoint Summary for JFET Test

3.6.3

A complete discussion of SPA measurements is well be­yond the scope of this manual. However, there are a few
points that should be kept in mind when using this ar­rangement. Additional measurement considerations
may be found in Section 2, paragraph 2.7 of this inshuc-

tion manual.

SPA Measurement Considerations

JmT

Tested

Crosspoints Closed*

&~urce, Gate, Drain)

I

3-15

SECTION 3
Applications

” 7 11 , Analyzer

HP 4145 Semiconductor Parameter

,,

Triax

Cables

Triax

Cables

Cigure3-12. SPA Connections

181

7072-HV t&ix
CCWI

Triax-SNC

Adapters (Model 7078-TRX-SNC)

-I

3-16

SECTION3

Applications

FETs Under

FETs Under

Test

Test

A A

1 1

2 2 3 3

4 4

Triax

Cables

I

7072.HV Matrix Card

i----------A

707 Switching Matrix

Figure 3-13. System Configuration for JFET Test

HP 41458 Semiconductor

Parameter Analyzer

I
I

3-17

SECTION 3

Applications

Procedure

1. Connect the system and devices to&her. as shown
in Figure 3-131

2. Turn on the HP 41458 and allow it to go through its
boot-up routine.

- -

3. Turn on the Model 707 Switching Matrix.

4. From the HP 41458 main menu, select the channel
definition page, then choose the FET VDS-IO applica­tion.

5. Press the PAGE NEXT key, and program the scurce
parameters, as required.

6.

Press the

PAGE NEXT key, and program the re-

quired graphing parameters.

7. Press the PAGE NEXT key to display the graph for­mat.

ID

OW

8. From the front panel of the Model 707, close the
crosspoints necessary to connect the FJZT being
tested to the SMUs (see Table 3-3).

9. Press the MEASUREMENT SINGLE key to initiate
the sweep. The SPA will generate the IO vs. VDS
curves at specified VGS values.

10. Open the crosspoints presently closed.

11. Repeat steps 8 and 9 for the remaining devices, as re­quired.

Typical Plot
Figure 3-14 shows a typical plot made using the proce-

dure above. The device tested was a 2N4392 N-channel
JFET. For the graphs, VOS was swept from OV to 1OV in

0.W increments, and Vcs was stepped from 0 to -1025V.

Variable 1 :

VDS -Ch2
Linear sweep
Start

stop 1o.ooov
step .1ooov

Variable 2 :

VG

-ChZ

Start

stop
step

.OOOO”

.OOOO”

-1 .OOOO”

-2500”

3.500

ldiv

‘igure 3-14. Typical JFET Plot

VDS l.OOO/div (V)

constante :

“S -Chl

.OOOO”

3-18

SECTION 3

Applications

REFERENCES

ASTM, F76-84. “Standard Method of Measuring Hall Mobility and Hall Coefficient in Extrinsic Semiconductor Single
Crystals.” Annual Bk. ASTM Stds., 1986: 10.05 155.

Coyle, G. et al Switchine Handbook. Keithley Instruments Inc., Cleveland, (1987).

Nicollian, E.H. and Brews, J.R. MOS Phvsics and Technolow. Wiley, New York (1982).

Sze, S.M. Phvsics of Semiconductor Devices, 2nd. edition. Wiley, New York (1985).
Van der Pauw, LJ. “A Method of Measuring Specific Resistivity and Hall Effects of Discs of Arbitrary Shape.” PhiliDs

Rec. Rmts.. 1958: 13 1.
O~erationandSenriceManual,Model4145ASemiconductorParameterAnalvzer.Yokogawa-Hewlett-PackardLtd,To-

kyo, Japan (1982).

3-19

SECT

EON 4

Service In

4.1 INTRODUCTION

This section contains information necessary to service the
Model 7072~HV Semiconductor Matrix Card and is ar-

ranged as follows:

4.2 Handling and Cleaning Precautions: Discusses
handling precautions and methods to clean the card
should it become contaminated.

4.3 Performance Verification: Covers the procedures
necessary to determine if the card is operating properly.

4.4 Special Handling of Static-Sensitive Devices: Re­views precautions necessary when handling static-sensi­tive devices.

4.5 Troubleshooting: Presents some troubleshooting
tips for the Model 7072~HV.

4.6 Principles of Operation: Briefly discusses circuit
0pWki0*.

4.2 HANDLING AND CLEANING PRECAUTIONS

formation

board. Once the flux has been removed, swab only
the repaired area with methanol, then blow dry the
board with dry nitrogen gas.
After cleaning, the card should be placed in a 50°C

4

low-humidity environment for several hours before
use.

4.3 PERFORMANCE VERIFICATION

The following paragraphs discuss performance verifica­tion procedures for the Model 7072~HV, including relay
testing, contact resistance, contact potential, path isola­tion, and leakage current.

4.3.1

All verification measurements except for path isolation
and offset current should be made at an ambient tem­perature between 0°C and 35°C and at a relative humid­ity of less than 70%. Path isolation and offset current veri-

fication must be performed at an ambient temperature of
23°C and at a relative humidity of less than 60% If the ma­trix card has be subjected to temperature or humidity ex­tremes, allow the card to environmentally stabilize for at
least one hour before performing any tests.

Environmental Conditions

Because of the high-impedance circuits on the Model
7072-I-N, care should be taken when handling or servic­ing the card to prevent possible contamination. The fol­lowing precautions should be taken when servicing the

card.

1. Handle the card only by the edges and handle (do
not touch the edge connectors). Do not touch any
board surfaces or components not associated with
the repair.

2. Do not store or operate the card in an environment
where dust could settle on the circuit board. Use dry
nitrogen gas to clean dust off the board if necessary.

3. Should it become necessary to use solder on the cir­cuit board, remove the flux from the work areas
when the repair has been completed. Use Freon@
TMS or TE or the equivalent along with clean cotton

swabs or a clean, soft brush to remove the flux. Take
care not to spread the flux to other areas of the circuit

4.3.2 Recommended Test Equipment

Table 4-l summarizes the equipment necessary to make

the performance verification tests, along with the appli­cation for each item.

4.3.3 Relay Testing

The relays on Model 7072-HV can be tested using the test
software supplied with the Model 707 Switching Matrix.
The following paragraphs discuss the test equipment

and connections. For detailed information on using the
test software, consult Section 6 of the Model 707 Instruc­tion Manual.

Recommended Equipment
. Model 707 Switching Matrix

4-l

SECTION 4
Service Information

Table 4-l. Recommended Verification Equipment

Qty. Description Application

1

Model 617 Electrometer

1

Model 196 6-l /2 Digit DMM

1

Model 707 Switching M&lx Au tests

1

IBM PC or HP 200 or 300 computer

4

Model 707S-TRX-10 triax cables*

2

Model 707S-TlW-3 t&x cables

1

Model 6172 2-slat male to 3-lug female triaxial adapter

3

Model 707%TRX-T triax tee adapter

5

Banana plugs (part # BG-IO-2*)

1

Relay test terminal block* Relay test

These items are used to c~nstrwt special cables; see text

l Unterminated 3slot triax cables (21, made by cutting

one TRX-7078-10

cable in half

. Relay test software (supplied with Model 707)

l IBM PC compatible or Hewlett Packard Series 200 or

300 computer

l Relay test connector (supplied with Model 707)

Offset current; path isolation
Path resistance

Relay test
Offset current; path resistance
path isolation, offset current
Offset current

Path resistance
Path isolation and resistance

Terminal Block

Connections

The test cable should be prepared using the information
shown in Figure 4-l. The center conductor of the unter­minated end of one triax cable should be connected to pin

1 of the relay test connector, while the inner shield should
be connected to pin 2. The outer shield should be cut off
and be left floating at the test connector end.

The remaining triax cable should be connected as fol-

lows: connect the center conductor to pin 6, and connect
theinnershield topin5. Again,theoutershield shouldbe

left floating. Also, jumper pins 5 and 6 of the relay test

connector together.

Figure 4-2 shows how to connect the prepared test cable
to the Model 7072-I-N. Connect the first t&x cable to row
A of the card, and connect the second triax cable to row B.

Figure 4-1.

Test Cable Preparation

Also be sue to connect the test connector to the RELAY
TEST jack on the rear panel of the Model 707.

Running the Test

Follow the instructions given in the Model 707 Instruc­tion Manual to perform the relay test. The computer will
advise you as to which relay or group of relays (if any) fail
to pass the test.

4-2

CONWC

to

ROWS

A+8

Model -

7072.HV
Card

SECTION 2

Service Information

Triax Cables

-A

707 Switching Matrix

Figure 4-2.

Connecting the Test Cable to the Model 7072XV

4.3.4 Offset Current Verification

Recommended Equipment

l Model 707 Switching Matrix
l Model 617 Electrometer
l Model 7078-TRX-3 Triax Cable
l Model 6172 2-slot maIe to 3-lug female triaxiaf adapter

Test Connections

Figure 4-3 shows the test connections for offset current
verification. TheMode17072-HV row being tested is to be
connected to the Model 617 Electrometer input through
the triaxial cable and the triaxial adapter. Note that the

electrometer ground strap is to be removed, and the elec­trometer should be operated in the unguarded mode.

Procedure

NOTE
The following procedure should be per­formed at an ambient temperature of 23°C
and at a relative humidity of less than 60%.

1. Turn on the Model 617 power and allow it to warm
up for two hours before beginning the verification
procedure.

2. With the power off, install the Model 7072-HV in the
desired slot of the Model 707 Switching Matrix. Re­move alI other cards from the instrument, and install

the slot covers.

3. After the prescribed warm up period, select the
amps function and the 2pA range on the Model 617.
Zero correct the instrument, and then select

autorsnging.

4. Connect the Model 617 to row A of the Model

7072-HV, as shown in Figure 4-3.

5. Close crosspoint Al by using the Model 707 front

panel controls.

4-3

SECTION4
Service

Information

6172 2-Slot to

7072-t-N Matrix Card

Figure 4-3.

6. Disable zero check on the Model 617, and allow the ter from row B, and connect it to row C.

. .-_. . .

reacimg to settle.

7. Verify that the offset current reading is <IpA.

8. Enable zero check on the Model 617, and open
crosspoint Al.

9. Repeat steps 5 through 8 for crosspoints A2 through

A12. Only one crosspoint at a time should be closed.

10. Disconnect the hiax cable from row A, and connect it
instead to row B.

11. Repeat steps 5 through 8 for crosspoints Bl through

812. Only one crosspoint at a time should be closed.

12. With zero check enabled, disconnect the electrome-

Offset Verification Test Connections

13. Close crosspoint Cl by using the front panel controls
of the Model 707.

14. Disable zero check, and allow the reading to settle.

15. Verify that the offset current reading is <20pA.

16.

Enable zero check, then open the crosspoint pres­ently closed.

17. Repeat steps 12 through 16 for rows D through H.

The electrometer should be connected to the row be-

ing tested, and only one crosspoint must be closed at
a time. The offset current for each crosspoint should
be dOpA.

4-4

Service

SECTION 2

Information

4.35

Path Isolation Verification

Recommended Equipment
. Model 707 Switching Matrix

The procedure for verifying path isolation is discussed
below. Should the card fail any of the tests, clean it using
the procedures outlined in paragraph 4.2. If rows C
through F still fail, the problem may lie in contamination
of the mainframe backplane.

. Model 617 Electrometer
. Model 7078-TRX-3 triaxial cable
. Unterminated 3-&t triaxial cable (cut connector off

7078-TRX-3)

. Banana plug (Keitbley part #BG-10-Z)

l #16-18AWG insulated stranded wire (6 in. length)

Test Connections

NOTE
If the path isolation for specific rows is below
standards, test the associated rows or col­umns with the card removed from the main­frame. (Of course, it will not be possible to

Figure 4-4 shows the test connections for the path isola­tion tests. One row being tested is to be connected to the
Model 617 Electrometer input through a Model 6172

2slct female to 3-lug male triaxial adapter. The other row
close crosspoints with the card removed.) If is to be connected to the voltage scurce HI terminal using
rows C-F pass with the card removed but fail
with the card installed, the backplane in the

a specially prepared 3.slot triax-to-banana plug cable, the

construction of which is shown in Figure 4-5. Note that
mainframe may require cleaning. See the both the inner shield and the center conductor are to be
Model 707 Instruction Manual. connected to the banana plug as shown.

Guard off

7076-TRX-3 Triax Cable

I

r Ground Link h

/I’

User-PreDared Triax Cable

(Sed Figure 4-5)

617 Electrometer

Warning : Hazardous voltage from

the electrometer scarce

may be present on terminals.

8

~@I

A@

I II

@ll

HQ

@12

8

Fiwre 4-4. Connections for Path Isolation Verification

7072-HV Matrix Card

4-s

SECTION 4
Service Infomation

,cut

/ /

r

/

Cut

,

L 1”LI

(A) Cut off insulation with knife.

Cut off cuter shield.

Insulation Over
Inner Shield

I-

(6) Strip insulation off Inner shield

(C) Twist inner shield then strip Inner conductor.

Twist inner shield and center conductor together,

slip on plastic cover.

(E) Screw on plastic cover.

?gure 4-5.

COM and the LO terminal of the electrometer voltage

source must be connected together as shown. Also, the
ground link between COM and chassis must be removed,
and the Model 617 guard must be turned off for current
measurements.

Trimid Cable Preparation

Procedure

WARNING
Hazardous voltage from the electrometer
voltage source will be used in the following

steps. Take care not to contact live circuits,

which could cause personal injury or death.

NOTE

The following procedure must be performed

at an ambient temperature of 23°C and at a

relative humidity of less than 60%.

1. Turn on the Model 617 and allow it to warm up for
two hours for rated accuracy.

2. With the mainframe power turned off, plug the
Model 7072-H!! into slot 1 of the mainframe. Re-

move

all

other

cards from the mainframe, and install

the slot covers.

3. After the prescribed warm up period, select the
Model 617 amps function, and enable zero check. Se-

lect the 2pA range, and zero correct the instrument.

4. Connect the Mode1617 to rows A and B of the matrix

card, as shown in Figure 4-4.

5. Program the Model 617 voltage source for a value of

+lOOV, but do not yet turn on the voltage source cut­put.

6. Close crosspoints Al and 82 by using the switching

matrix front panel controls.

7. With the Model 617 in amps, enable suppress after

the reading has settled.

8. Turn on the Model 617 voltage source output, and

enable the V/I ohms function on the electrometer.

9. After the reading has settled, verify that the resis-

tance is >lOTQ (IO’Q).

10. Turn off the voltage source, and enable zero check.
Disable suppress, and select the amps
the electrometer.

11. Open crosspoints Al and B2, and close crosspoints
A3 and B4.

12. Repeat steps 7 through 11 for A3 and 84.

13. Repeat steps 7 through 12 for crosspoint pairs A5
and B6, A7 and BE, A9 and BlO, and All and B12.

14. Disconnect the electrometer from rows A and B, and
connect it instead to rows C and D.

15. Repeatsteps7through13forrowsCandD. Thepath
isolation for these rows should be >lTQ (lO?Q).

16. Repeat steps 7 through 14 for row pairs E and F, and
G and H. For each row pair, step through the
crosspoint pairs 1 and 2,3 and 4,5 and 6,7 and 8,9
and 10, and 11 and 12. The complete procedure out-

function

on

4-6

SECTION 2

Service Information

lined in steps 7 through 11 should be repeated for

each crosspoint pair. Each resistance measurement

for rows E through H should be >lTQ (lo%&

4.3.6 Path Resistance Verification

The following paragraphs discuss the equipment, con-

nections, and procedure to check path resistance. Should
a particular pathway fail the resistance test, the relay (or
relays) for that particular crosspoint is probably defec­tive. See the schematic diagram at the end of Section 5 to
determine which relay is defective.

Recommended Equipment

0 Model 196 DMM

. 7078-TRX-T hiax tee adapters (3)

l Unterminated 3-slot triax cables (4), made from two

7078.TRX-10 trim cables.

. Banana plugs (4), Keithley part number BG-10-Z

Connections

Figure 4-6 shows the connections for the path resistance
tests. The Model 196 is to be connected to the mw and col-

unn jacks using prepared triax/banana cables (Figure

4-5, but with inner shield and center conductor discon-

nected.) and 7078-TRX-T triax tee adapters. The special
cables can be made from two 7078-TRX-10 cables each cut
in half, or four 7078-TRX-3 cables by cutting one triax
connector off each cable.

Figure 4-6.

707%HV Matrix Card

Connections for path Resistance Verification

SECTION 4
Service information

Procedure

1. Turn on the Model 196 DMM and allow it to warm
up for at least one hour before beginning the test.

2. With the power off, install the Model 7072~HV card
in slot 1 of the mainframe.

3. Connect the four triaxial cables to the Model 196 and
the two triax tee adapters (Figure 4-6), but do not yet
connect the adapters to the Model 7072-H!!.

4. Temporarily connect the two triax tee connectors to­gether using a third triax tee adapter, as shown in
Figure 4-7.

5. Select the ohms function, 3OOQ range, and 6-l/2
digit resolution on the Model 196.

6. After the reading settles, enable zero on the Model
196 DMh4. Leave zero enabled for the remainder of
the tests.

7. Disconnect the two triax tee adapters from the short­ing adapter, and connect the two adapters with the

cable to the row A and column 1 connectors on the

Model 7072~HV (see Figure 4-6).

8. Close crosspoint Al, and allow the reading to settle.

9. Verify that the resistance reading is <3.5Q.

10. Open the crosspoint, and disconnect the triax adapt­er from column 1. Connect the adapter to column 2.

11. Repeat steps 8 through 10 for columns 2 through 12.
In each case, the column adapter must be connected
to the column under test, and the crosspoint must be

closed.

12. Disconnect therowadapterfromrow A, andconnect
it instead to row B.

13. Repeat steps 8 through 10 for row B. The crosspoints

of interest here are Bl through 812. Also, the row
adapter must be connected to the row being tested.

14. Repeat steps 8 through 13 for rows C through H. In
each case, the crosspoint to close is the one corre­sponding to the row and column connections at that

time. In all cases, the measured resistance should be
<3.5Q.

TO

196

Figure 4-7. Shorting Measurement Paths Using Trim Tee Adapter

SECTION 2

Service Information

4.4 SPECIAL HANDLING OF STATIC­SENSITIVE DEVICES

CMOS and other high-impedance devices are subject to
possible static discharge damage because of the high-im­pedance levels involved. When handling such devices,
use the precautions listed below.

NOTE

In order to prevent damage, assume that all

parts are static sensitive.

1.

Such devices should be transported and handled
only in containers specially designed to prevent or
dissipate

will be received in anti-static containers made of

plastic or foam. Keep these parts in their original
containers until ready for installation or use.

2.

Remove the devices from their protective containers
only at a properly-grounded work station. Also
ground yourself with an appropriate wrist strap
while working with these devices.

3.

Handle the devices only by the body; do not touch
the pins or terminals.

4.

Any printed circuit board into which the device is to
be inserted must first be grounded to thebench or ta­ble.

5.

Use only anti-static type de-soldering tools and
grounded-tip soldering irons.

static

build-up. Typically, these devices

4.5 TROUBLESHOOTING

4.5.1

Table 4-2 summarizes the recommended equipment for
general troubleshooting.

4.5.2

In order to gain access to the test points and other cir­cuitry on the Model 7072-HV, the card must be plugged
into the Model 7070 Extender Card, which, in turn, must
be plugged into the desired slot of the mainframe. The
Model 7070 must be configured as an extender card by
placing the configuration jumper in the EXTEND posi­tion. See the documentation supplied with the Model
7070 for complete details on using the card.

4.5.3

Table 4-3 summarizes the troubleshooting procedure for
theModel7072-HVSemiconductorMatrixCard. Someof
the troubleshooting steps refer to the ID data timing dia­gram shown in Figure 4-8. In addition to the procedure
shown, the relay tests outlined in paragraph 4.3.3 can be
used to aid in troubleshooting. Also, refer to paragraph

4.6 for an overview of operating principles.

Recommended Equipment

Using the Extender Card

NOTE
The Model 7070 cannot be used for perform­ing the verification tests because its presence
will affect the results.

Troubleshooting Procedure

Table 4-2. Recommended Troubleshooting Equipment

~

Keithle 7070 Allow circuit access

4-9

SECTION 4
Service information

Table 4-3. Troubleshooting Procedure

step Item/Component

Required Condition

1 TP2

l-PI

2
3 TP3
4 TP4

Tl’5

5

TP6

6

Tp7

7
8 TP8
9 TP9

10 TPIO

+6VDC
+5vLx Logic voltage
NEXT ADDR pulses
CLR ADDR pulse
ID data pulses
STROBE pulse End of relay data sequence.
Relay data (128 bits)
CLK pulses
High on power up until first STROBE Power on safe guard.
sets low.

11 U30-U45, pins lo-18 Low with relay energized, high with

relay de-energized.

CARDSEL

CLRADDR (TP5)

l-l

comments

All voltages referenced to TP2 (digital

COIlllllOn)

Relay voltage
I’ower up only (Fig. 4-S)

Power up only (Fig. 4-8)
Power up only (Fig. 4-8)

Present when updating relays.
Present during relay data or ID data.

Relay driver outputs

NEXTADDR (TP4)

CLK (TP9)

IDDATA (TP6)

Note :

ID data sequence cccurs on power-up only.

CLRADDR pulse occur.s only once.

Figure 4-8. ID Data Timing

HI-Z

x-xxxxxxxx

D7 D6 D5 D4 D3 D2 D, DO

HI-.?

4-10

SECTION 2

Service Information

4.6

1ne rouowmg paragrapns clxxuss 1‘1

The following paragraphs discuss the basic operating

PRINCIPLES OF OPERATION

principles for the Model 7072-HV. A SI principles for the Model 7072-HV. A schematic diagram
of the matrix card may be found in of the matrix card may be found in drawing number
7072~HV-106 (four sheets), located at th 7072~HV-106 (four sheets), located at the end of Section 5.

4.6.1

Block Diagram

Fieue4-9showsasinmlified blockdiazramof theMode
70?2-HV. Key element’s include the b&r W461, ID data
circuits (U14, U27, and U47), relay drivers (U3OJJ45) and
relays (Kl-KlZS), and power-on safe guard (U29). The
major elements are discussed below.

Address
Counter

AO-A11

ROM

DO-D7

4.6.2

ID Data Circuits

Upon power up, the card identification data information
from each card is read by the mainframe. This ID data in­eludes such information as card ID, hardware settling
time for the card, and a relay configuration table, which
tells the mainframe which relays to close for a specific
crosspoint. This configuration table is necessary because
some cards (such as the Model 7072-HV) require the clos­ing of more than one relay to close a specific crosspoint.

ID data is contained within an on-card ROM, U27. In or­der to read this information, the sequence below is per­formed upon power up. Figure 4-8 shows the general
timing of this sequence.

1. The CARDSEL line is brought low, enabling the
ROM outputs. This line remains low throughout the
ID data transmission sequence.

PX&?

to Serial

COllVWlH

TO

Mainframe

u14

U27

IDDATA

RELAYDATA

Power-On
Safeguard

u29

CLK _ >

output

Enable

u47

R&y Relays

Drivers -

wo-u45 HV

h

Column

Lock-out

Ki -K128

Columns

i-12

- A-H

ROWS

Figure 4-9.

Model 7072~HV Block Diagram

4-11

SECTION 4
Service Information

2.

The CLRADDR line is pulsed high to clear the ad-

dress counter and set it to zero. At this point, a ROM
address of zero is selected. This

OIICE

3.

The NEXTADDR line is set low. NEXTADDR going
low increments the counter and enables parallel
loading of the parallel-to-serial converter. NEX-

TADDR is kept low long enough for the counter to

increment and the ROM outputs to stabilize. This se­quence functions because the load input of the paral­lel-to-serial converter is level sensitive rather than
edge sensitive. The first ROM address is location 1,
not 0.

4.

The CLK line clocks the parallel-to-serial converter

to shift all eight data bits from the converter to the
mainframe via the IDDATA line.

Theprocessinsteps3and4repeatsuntilall thenecessary
ROM locations have been read. A total of 498 bytes of in­formation are read by the mainframe during the card ID
sequence.

pulse occurs

only

4.6.3 Relay Control

The relays are controlled by serial data transmitted via
the RELAYDATA line. A total of 16 bytes for each card

are shifted in serial fashion into latches located in the 16
relay drivers, U30-U45. The serial data is fed in through
the DATA lines under control of the CLK signal. As data
overflows one register, it is fed out the Q’S line of that reg­ister to the next IC down the chain.

Once all 16 bytes have been shifted into each card in the
mainframe, the STROBE line is set high to latch the relay
information into the Q outputs of the relay drivers, and
the appropriate relays are energized (assuming the
driver outputs are enabled, as discussed below). Logic
convention is such that the corresponding relay driver
output must be low to energize the associated relay,
while the output is high when the relay is de-energized.

For example, if the Ql output of U35 is low, relay Kl will
be energized.

4.6.4 Power-on Safeguard

A power-on safeguard circuit, made up of U29 and asso­ciate components, ensures that relays do not randomly
energize upon power-up. The two AND gates, U29, make
up an R-S flip-flop. Initially, the Q output of the flip-flop

(pin 3 of U29) is set high upon power up. Since the OEN
terminals of the relay drivers U30-U45 are held high,
their outputs are disabled, and all relays remain de-ener­gized regardless of the relay data information present at
that time.

The first STROBE pulse that comes along (in order to load
relay data) clears the R-S flip-flop, setting the OEN lines
of U30-U45 low to enable their outputs. This action al­lows the relays to be controlled by the transmitted relay
data information.

A hold-off period of approximately 470msec in included
in the safeguard circuit to guard against premature ena­bling of the relays. The time constant of the hold-off pe­riod is determined by the relative values of Rl and CZO.

4.6.5 Isolator Relays

Row and column isolator relays are necessary in addition
to the crosspoint relays in order to ensure the integrity of
low-level signal pathways (rows A, B, G, and H). Row
isolator relays include K121 through K128, while column
isolators are K25 through K36, and K85 through K96. The
necessary isolator relay(s) are closed in addition to the se­lected crosspoint to complete the entire pathway. For ex­ample, if crosspoint Cl0 is closed, relays K34, K46, and
K123 would be energized. If a crosspoint in rows A or B is
closed, the isolator relay in that column will not close
even if a crosspoint in rows C through H of that column is
closed. This is done to help keep high voltage off of rows
C through H.

4-12

SECTION 5

Replaceable Parts

5.1 INTRODUCTION

This section contains a list of replaceable electrical and
mechanical parts for the Model 7072~HV, as well as a
component layout drawing and schematic diagram of the
matrix card.

5.2 PARTS LISTS

Electrical parts are listed in order of circuit designation in
Table 5-l. Table 5-2 summarizes mechanical parts.

5.3 ORDERING INFORMATION

To place an order, or to obtain information about replace­ment parts, contact your Keithley representative or the
factory (see the inside front cover of this manual for ad-

dresses). When ordering parts, be sure to include the fol­lowing information:

1. Matrix card model number (7072~HV)

2. Card serial number

3. Part description

4. Circuit designation, if applicable

5. Keithley part number

5.4 FACTORY SERVICE

Jf the matrix card is to be returned to Keithley Instru­ments for repair, perform the following:

1.

Complete the service form located at the back of this
manual, and include it with the unit.

2.

Carefully pack the card in the original packing car­ton or the equivalent.

3.

Write ATIENTION REPAIR DEPARTMENT on the
shipping label. Note that it is not necessary to return
the matrix mainframe with the card.

5.5 COMPONENT LAYOUT AND SCHEMATIC DIAGRAM

7072-HV-100 is the component layout for the Model
7072~HV. 7072~m-106 shows a schematic diagram of the
card on four separate sheets.

5-l

MODEL 7072-HV ELECTRICAL PARTS LIST

CIRCUIT
DESIG.

CR1
CR2

DESCRIPTION

DIODE,SILICON,lN4148 (DO-35)
DIODE,SCHOTTKY,lN5711

CR3 DIODE, SILICON, IN4006

Jl...J14
J15...JZO
JlOO...J103
J104...J107

K190...K227
K126...K189
KlOO...K125

CONN, TRIAX
CONN,TRIAX
CONN,SMB,MALE
CONN, SMB, MALE

RELAY,REED
RELAY,REED,(Dl’ST)
R!ZAY,(4I’ST)

Rl
R2
R3
R4
R5

i;...R18

KEITHLEY
PART NO.

c-314-10
C-237-.01
C-386-270P
c-64701
C-36.5.1

RF-28
RF-69
RF-38

CS-719
CS-630
‘Z-720
a-580

RL-143
RL-105
RL-104

R-76-47K
R-76.10K
R-76-1 20K
R-76-680
R-76.1lK
R-76-200
R-76.1K

TSlOO...TE149
Trl..TrlO

Wl

TERMINAL (TEFLON)
CONN,TEST POINT

STIFFENER,BOARD

TE-97-l
cs-553
IC-545

7072-HV-800
IC399
IC-536
IC-483
IC-548
IC-192
IC-444

J-16

MODEL 7072-HV, MECHANICAL PARTS LIST

DESCRIPTION

KEITHLEY
PART NO.

CABLE CLAMP
STANDOFFS
ASSEMBLYJEAR PANEL
CABLE ASSEMBLY
CAPJ’ROTECTIVE
FASTENER

HANDLE
SHIELD.REAR
SHIELD;ROW A
SHIELD,ROW B
STANDOFF
SOCKET FOR U27

cc-334
ST-137-l
7072-302
CA-54-l
CAP-30-I
FA-154-l
HH-33-1
7071311
7072-305
7072-306
7071-310
SO-69

M1 M2

M3

Service Form

Model No.

Serial No. Date
Name and Telephone No.
Company

List all control settings, describe problem and check boxes that apply to problem.

Cl Intermittent
0 IEEE failure 0 Obvious problem on power-up 0 Batteries and fuses are OK

0 Front panel operational 0 All ranges or functions are bad 0 Checked all cables
Display or output (check

m Drifts 0 Unable to zero

0 Unstable 0 Will not read applied input
0 Overload

m Calibration only
0 Data required
(attach any additional sheets as necessary)

Show a block diagram of your measurement system including all instruments connected (whether power is turned on or not).

Also, describe signal source.

one)

0 Analog output follows display

0 Certificate of calibration required

0 Particular range or function bad; specify

Where is the measurement being performed? (factory, controlled laboratory, out-of-doors, etc.)

What power line voltage is used?
Relative humidity?
Any additional information. (If special modifications have been made by the user, please describe.)

Other?

Ambient temperature?

“F

Specifications are subject to change without notice.
All Keithley trademarks and trade names are the property of Keithley Instruments, Inc. All other

trademarks and trade names are the property of their respective companies.

Keithley Instruments, Inc.

Sales Offices: BELGIUM: Bergensesteenweg 709 • B-1600 Sint-Pieters-Leeuw • 02-363 00 40 • Fax: [phone]

CHINA:

Yuan Chen Xin Building, Room 705 • 12 Yumin Road, Dewai, Madian • Beijing 100029 • 8610-6202-2886 • Fax: [phone]
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FRANCE: 3, allée des Garays • 91127 Palaiseau Cédex • 01-64 53 20 20 • Fax: [phone]
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© Copyright 2001 Keithley Instruments, Inc.

Printed in the U.S.A.

11/01