High-Voltage capacitance measurement system for SiC power MOSFETs

Adequate modeling of a power metal-oxide-semiconductor field-effect transistor (MOSFET) is dependent on accurate characterization of the inter-electrode capacitances. With the advent of high-voltage silicon carbide (SiC) power MOSFETs, it has become important to develop a measurement system that can perform and record high-voltage capacitance versus voltage measurements on these devices. This paper describes a measurement apparatus that safely and accurately allows high voltage capacitance-voltage (CV) measurements to be performed. The measurements are based on conventional LCR (inductance (L), capacitance (C), and resistance (R)) meter CV techniques but with added circuitry to interface the LCR meter to high voltage bias sources. The effects of the added circuitry are studied theoretically, and the CV measurement accuracy is verified with experimentation. High voltage capacitance voltage measurements are presented for both silicon and SiC power MOSFETs.