Degradation Behavior of SiC Trench MOSFETs by Total-ionizing-dose Irradiation Under Gate Voltage Stress

SiC MOSFETs total-ionizing-dose TID tolerance are highly related to the structure and the strength of the gate electric field. The primary failure mechanism is the accumulation of radiation-induced charges in the gate oxide layer, which results in a significant threshold voltage shift. SiC trench-gate MOSFETs display markedly lower TID tolerance (below 60 krad) compared to planar type, asymmetric devices exhibit the largest threshold voltage shift V-TH, and double-trench devices show the greatest degradation in on resistance R-ON, which is related to the thicker oxide layer and inferior interface radiation resistance. A high electric field above 2 MV/cm can diminish the oxide trap charges accumulation by hole capture cross-section reduce, thereby improving the TID tolerance of SiC MOSFETs.