Characterization and Modeling of a SiC MOSFET's Turn-On Overvoltage

Switching transient overvoltage is inevitable in hard switching applications, and the faster switching speed of SiC MOSFETs suggests even worse overvoltage. This paper focuses on the turn-on overvoltage. To understand its nature, the switching transient is analyzed, and it shows the turn-on overvoltage is largely independent of load current condition. This phenomenon is verified by characterizing the turn-on overvoltage of a SiC MOFET and a SiC Schottky diode. Finally, a SPICE-based model is also built to understand the switching transient more accurately, and the modeling method can accurately predict the turn-on overvoltage and help select device voltage rating.