Total Ionizing Dose Radiation Effect on Avalanche Robustness of 1200V Trench-type SiC Power MOSFETs

SiC power MOSFETs have been widely adopted in EVs, and increasingly gaining attentions from aerospace applications recently. However, radiation-related problems are still of great concerns before mass adoption in aerospace industries. In this paper, we investigated the total ionizing radiation (TID) effect on avalanche robustness of 1200V SiC power MOSFETs with symmetric trench gate structure. It is experimentally observed that the failure mechanism does not change, but both avalanche current and avalanche energy are significantly reduced after 100krad TID radiation. For example, the avalanche current and avalanche energy of SiC MOSFETs after 100krad radiation under V
GS
= 15V bias reduced by 3.9A (35.9%) and 80.2mJ (58.9%) by unclamped inductive switching test under 100V bus voltage and 5mH inductive load. Obviously, the avalanche robustness of SiC MOSFETs is greatly affected by TID radiation and proper harden methods are essential to avoid significant degradation in robustness of SiC MOSFETs before mass adoption into aerospace applications.