Technical data

Agilent 41000 Administration Guide, Edition 3 5- 15
Measurement Techniques
Low Current Measurements
To subtract the contact state offset current
In this way, the offset current is defined as the current measured when a device is
connected and it is in the off state. This will be acceptable for active devices such as
MOSFET and bipolar transistor. The offset current can be subtracted as shown below.
Summary • Contact state offset current measurement
• Low current measurement of device under test (DUT)
• Offset current subtraction
Procedure 1. Make open state at the end of the measurement path for the all output ports.
The measurement path should include the probe card, manipulator, or something to
contact pad/terminal of DUT.
2. Connect the current measurement port to a source monitor unit (SMU).
3. Connect unused output ports to the ground unit (GNDU) or other SMU.
4. Set the offset current measurement condition; integration time, measurement range,
output voltage, compliance, and so on.
• The integration time should be enough long (e.g. 16 power line cycles).
• The measurement range and compliance value must be the value (e.g. 10 pA, 10
mA) used for the actual
DUT measurement.
• The gate or base bias must be set to the value that keeps the DUT being off.
• All other source outputs must be 0 V.
5. Connect DUT.
6. Perform offset current measurement (Ioffset) about 50 times, for example. And
calculate the averaged value (Iaverage).
7. Set the low current measurement condition as you want.
Use the SMU used for the offset current measurement.
Do not change the setting of the integration time, measurement range, and compliance.
8. Perform current measurement (Imeasure).
9. Subtract the offset current from the measurement data by the following formula.
Iresult = Imeasure-Iaverage
Disconnect the DUT after all measurements are completed.