Section 12: Maintenance
Model 4200A-SCS Parameter Analyzer Reference Manual
12-8
4200A-901-01 Rev. C / February 2017
Making stable measurements with SMUs
The following topics discuss various considerations when making stable measurements, including
single-SMU stability, multiple-SMU stability, and avoiding oscillation.
Single SMU stability considerations
Driving inductive loads can cause current source instability. Current source instability almost never
occurs in semiconductor applications.
A SMU that is sourcing voltage is stable when driving capacitive loads up to 10 nF. However, at the
lower current measurement ranges, large capacitive loads may increase settling time and may cause
overshoot and ringing. To reduce this effect, you can add a small resistor in series with the capacitive
load. Choose a resistor that provides an R
C
time constant of 1 ms to 10 ms.
You can also increase the measurement delay factor for the test to reduce this effect:
1. In Clarius, select the test.
2. Select
Configure
.
3. In the right pane, select
Test Settings
.
4. Select
Advanced
.
5. Set the Speed to
Custom
.
6. Increase the
Delay Factor
.
Refer to
(on page 6-84) for additional information.
