The measured MOS capacitance (called gate capacitance) varies with the applied gate voltage.
1. A very powerful diagnostic tool for identifying any deviations from the ideal in both oxide and semiconductor
2. Routinely monitored during MMOS device fabrication
Measurement of C-V characteristics
–Apply any dc bias, and superimpose a small (15 mV) ac signal
–Generally measured at 1 MHz (high frequency) or at variable frequencies
between 1KHz to 1 MHz
–The dc bias VG is slowly varied to get quasi-continuous C-V characteristics