User`s guide

Agilent 4155C/4156C User’s Guide Vol.2, Edition 6 4-3

Quasi-static C-V Measurements

Measurement Functions

For quasi-static C-V (QSCV) measurements, the sweep source channel performs

linear staircase sweep output of voltage, while the monitor channel measures

capacitance for each sweep step.

Available Units

The QSCV measurement uses a voltage sweep source (VAR1), and a voltage

constant source. Also, optional constant sources may be used. Units, mode, and

function available are shown below:

Only a SMU can be used for the capacitance measurement. Specify the

measurement unit on the MEASURE: QSCV MEASURE SETUP screen.

Capacitance Data Calculation

At each sweep step, voltage and current are measured and the capacitance data is

calculated by using the following formula.

C = I × cinteg /(V - V

)

where, cinteg is the integration time of the capacitance measurement. I, V, and V

are the measurement data at each sweep step. Also, if the leakage current

compensation is enabled, the capacitance data is calculated by the next formula.

C = (I - Leak) × cinteg /(V - V

)

Leak is the leakage current and is given by the following formula.

Leak = IL + τ × (IL

- IL)/(2 × cinteg)

where, τ is the time for electrical charge.

Unit Mode Function

SMU V VAR1

V, I, COMMON CONST

VSU V CONST

PGU V CONST

GNDU COMMON CONST