Reliability and Failure Investigation of SiC MOSFET Under Avalanche

In this study, the reliability and failure mechanism of commercial SiC MOSFET under avalanche mode operation was investigated using experimental evaluation and TCAD simulation. The results shown that the breakdown voltage of SiC MOSFET exhibited a gradual upward trend with increase of avalanche energy. Besides, the SiC material inside could be burned down due to a local hot spot with extremely high value of heat power dissipation generating in avalanche breakdown position, which was about 3 orders of magnitude larger than that during proper switching operation. The SiC MOSFET would be damaged from gate oxide failure under avalanche operation due to interaction between sharply increase of temperature and high electric field, resulting in gate to drain short circuit.