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Introduction
HP’s 4140B pA Meter/DC Voltage Source provides a stable picoampere meter with maximum
resolution of 10-15A and two programmable dc
voltage sources. This, along with the programmable hold and step delay function, enables you to
make synchronized measurements on a device or
material.
0
Reliable, efficient pA current measurements need-
ed in R&D labs, production, and QA can now be
made with just one instrument, the 4140B.
Measurements on electronic components, insula-
tion materials, and especially semiconductor
devices are fast, convenient and accomplished with
ease.
Stable
Current
Measurements
The 41409 makes very stable, high resolution current measurements to + 1.000 x
10.‘*A (1 x 10-15A maximum resolution)
that were previously very difficult to make.
The Zero offset cancels up to
leakage current of test leads or fixtures in
the Current (I, I-V) modes, and up to
pF stray capacitance in the C-V mode. The
zero capability, along with low noise test
leads (16053A) and electrostatic/light
shielded test fixture (16055A), lets you
measure low pA currents with confidence.
100 x 10-15A
100
Synchronized pA
Measurements
Two internal programmable dc
sources provide staircase, ramp,
dc
level outputs. The start, stop, and step
voltages can be set from -
V
with
10 mV
resolution and the hold/step
delay times can be set depending on the
characteristics of the device or material
being tested. These features, together with
100 V
the pA measurement section, provide an
automatically synchronized measurement.
voltage
and stable
to +
100
HP-IB’ Operation
Systems integration is easily accomplished
with the HP-IB interface, allowing remote
programming of all front panel controls.
Measurement data can be taken into the
controller, processed, and then displayed
in a variety of formats. This is especially
effective in the manufacturing process
where rapid feedback is essential.
*HP-IB (Hewlett-Packard Interface Bus)
is Hewlett-Packard’s implementation of
IEEE 488-l 975, ANSI Standard #MC1 .l
Selectable
Function / Integration
Times /Line Filter
The synchronized measurement capability
allows current-voltage (I-V) and
capacitance-voltage (C-V) measurements
in addition to the normal pA current (I)
measurements. Ranging is automatic or
manual (up/down).
A
significant feature is the selectable
integration time (short, medium, or long).
This allows a trade-off of speed vs. accuracy in current measurements.
The filter function enables accurate 1 pA
measurements even when noise is
times greater than the DC current being
measured.
2
1000
Self Test/Analog Output
The automatic self test functionally verifies
proper operation of the digital and analog
circuitry.
The Analog Output supplies X-Y recorder
outputs necessary for plotting I-V and C-V
data. This includes measurement data, pen
control, and upper
voltages.
and lower limit
in Picoampere Current
Source Current Limit
To protect the material or device under
test, the 4140B has a programmable current limit capability on both internal dc
sources. Current limits of 10-4, lo-“, 10’2A
are selected either manually or under HPIB control.
Voltage Sweep Functions
Flexible voltage sweep control capability
allows operator to optimize any current
voltage measurement. Controls are
AUTO/START, MAN (PAUSE) for
changing step voltage/sweep direction
during a measurement, STEP (I. t), and
ABORT.
Measurements
PARAMETER MEASURED
DISPLAY
Key Features
I, I-V & c-v
Can also be used as a programmable
source/function generator (DC, ramp
1 & staircase).
O.lpF - 1999 pF
Quasi-Static C-V
Measurements
A capacitance measurement utilizing a
ramp voltage (quasi-static or dc C-V
measurement) is employed as one method
of evaluating semiconductors. In the
4140B. capacitance is calculated from the
measured current I that is synchronized
with a ramp voltage dV/dt (C = I/dV/dt).
Capacitance change can also be displayed
as a percent of Cox (the capacitance of the
oxide layer).
Parameter Selection / Data
Entry
Parameter selection and data entry is
accomplished either manually from- the
front panel or via the HP-IB. Select the
parameter (START V, STOP V, HOLD
TIME...), enter the appropriate data
(voltage, time, or ramp rate) and press the
ENTER key. Each data entry is stored in
memory. The measurement is then made
automatically by pushing. the START key,
SWEEP MODE
AUTO/Manual (Pause)
I
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