Choosing The Right Parameters; Optimal C-V Measurement Parameters - Keithley 4200A-SCS Reference Manual

Hide thumbs Also See for 4200A-SCS:

Table of Contents

Appendix D: Using a Model 82 C-V System

Choosing the right parameters

This section describes how to choose the correct parameters for:

Simultaneous C-V measurement

The delay time to ensure that the device remains in equilibrium in the inversion region during a

Controlling errors at the source

Simultaneous C-V measurement is a complicated matter. Besides system considerations, you should

carefully choose the measurement parameters. Refer to the following discussion for considerations

when selecting these parameters.

Start, stop, and step voltages

Most C-V data is derived from the sweep transition, or depletion region of the C-V curve. For that

reason, start and stop voltages should be chosen so that the depletion region makes up about 1/3 to

2/3 of the voltage range.

The upper flat, or accumulation region of the high frequency C-V curve defines the oxide capacitance,

COX. Since most analysis relies on the ratio C/COX, it is important that you choose a start or stop

voltage (depending on the sweep direction) to bias the device into strong accumulation at the start or

the end of the sweep.

You should carefully consider the size of the step voltage. Start, stop, and step size determine the

total number of data points in the sweep. Some compromise is necessary between having too few

data points in one situation, or too many data points in the other.

Model 4200A-SCS Parameter Analyzer Reference Manual

Figure 600: Typical simultaneous C-V curve

4200A-901-01 Rev. C / February 2017