Short Circuit Robustness and Carrier Lifetime in Silicon Carbide MOSFETs

Short circuit (SC) operation can lead to thermal runaway failures of SiC MOSFETs associated with leakage current uncommon to unipolar power devices. This paper presents the physical models required to simulate the leakage current in SiC power MOSFETs during SC accurately. It is shown that the SRH-generation carrier lifetime significantly affects the SC performance of SiC MOSFET, depending on defects in the epitaxial layer and processing induced damage. The temperature and field dependence of carrier lifetime as well as the surface recombination velocity are investigated and their influence on the SC current of a 1.2 kV SiC power MOSFET are presented.