Switching Speed Comparison of Medium-Voltage SiC MOSFETs (3.3 kV - 10 kV)

As the industry shifts toward higher voltage classes of semiconductor devices such as 6.5 kV and 10 kV SiC MOS-FETs, these devices exhibit intrinsically faster switching speeds. This requires a re-evaluation of the design regime on parasitic optimization priority in power module design, which previously have been primarily focused at lowering the parasitic inductance. This paper presents a theoretical analysis of switching speed changes with breakdown voltage based on device cell structure, and the experimental comparison of the switching speed (dv / dt and di/dt) of MV SiC MOSFETs with blocking voltages of 3.3 kV, 6.5 kV, and 10 kV. The results reveal that higher-voltage SiC MOSFETs experience higher dv/dt with same gate resistance, indicating that SiC MOSFETs are more sensitive to parasitic capacitive couplings as breakdown voltage increasing. While the di/dt of three chosen SiC MOSFETs overlay with each other with same gate resistance. These findings provide quantitative insights into breakdown-voltage-dependent switching speed, serving as a practical guideline for future MV SiC MOSFET power modules featuring high-voltage and high-current capability.