Agilent Technologies EasyEXPERT, Manual, Page: 416 / 610

15 Structure
15.4 Cgb-Vg 2Freq: MOS capacitor Cgb-Vg characteristics, 2-frequency method
(A.01.11)
[Supported Analyzer]
B1500A
[Description]
Measures the Gate-Substrate capacitance (Cgb) by using two-frequency method, and plots the Cgb-Vg
characteristics.
DC bias output is performed from -VgbStart to -VgbStop in -VgbStep steps.
The Cgb value is given by the following formula. Then C1 and C2 are capacitance, D1 and C2 are dissipation
factor measured at the frequency (f1 and f2).
Cgb = [f1^2*C1*(1+D1^2)-f2^2*C2*(1+D2^2)]/[f2^2-f1^2]
For a more accurate measurement, perform correction data measurement at the measurement frequency before
starting the capacitance measurement.
If the measurement frequency is not included in the list of default frequencies below, click the Advanced
Options... button and set the measurement frequency on the Frequency area of the Advanced Options for CMU
Calibration window.
Default frequencies:
1 k, 2 k, 5 k, 10 k, 20 k, 50 k, 100 k, 200 k, 500 k, 1 M, 1.2 M, 1.5 M, 2 M, 2.5 M, 2.7 M, 3 M, 3.2 M, 3.5 M,
3.7 M, 4 M, 4.2 M, 4.5 M, 5 MHz
[Device Under Test]
MOS capacitor
Connect Gate to the CMU Low, and Substrate to the CMU High.
[Device Parameters]
Polarity: Nch (CMU forces the specified value) or Pch (CMU forces the negative specified value).
Lg: Gate length
Wg: Gate width
Temp: Temperature
[Test Parameters]
IntegTime: Integration time
FREQ1: Measurement frequency #1
FREQ2: Measurement frequency #2
OscLevel: Measurement signal level
Gate: CMU connected between Gate and channel (CV sweep measurement)
VgbStart: DC bias start voltage
VgbStop: DC bias stop voltage
VgbStep: DC bias step voltage
[Extended Test Parameters]
HoldTime: Hold time
DelayTime: Delay time
[Measurement Parameters]
Parallel capacitance Cp
Dissipation factor D
Agilent EasyEXPERT Application Library Reference, Edition 8
15-8