Study of bias-induced total ionizing dose radiation damage mechanism in SiC MOSFETs

γ-ray irradiation experiments are conducted at different biases to investigate the differences in total ionizing dose damage of SiC MOSFET by the I-V and Split C-V curves. Combined with TCAD simulation, it is found that the total ionizing dose effect at different biases can generate positive charges at different locations in the oxide. For gate and motor-drive bias, the charges are uniformly located in the SiO2 layer, causing a negative shift of the C-V and I-V curves. For drain bias, charges are mainly in the JFET oxide due to the inhomogeneous distribution of the electric field in the oxide, resulting in a change in the shape of the C-V curve. The results further deepen our understanding of the radiation damage mechanism of SiC power MOSFETs.