Silicon carbide(SiC)is a promising wide-bandgap semiconductor material owing to its excellent electrical and thermal characteristics.Power metal-oxide-semiconductor field-effect transistors(MOSFETs)based on SiC are suitable for high-power fields,and their high-temperature gate oxide reliability is one of the most concerned characteristics.In this paper,the high-temperature gate oxide reliability of self-developed SiC MOSFETs is compared with that of the foreign SiC MOSFETs of the same specification by positive and negative high-temperature gate bias(HTGB)tests.The negative HTGB test results show that the deviation of threshold voltage of self-developed SiC MOSFETs is almost equal to that of the foreign SiC MOSFETs,and the maximum discrepancy between them is about 4.52％.However,the positive HTGB test results show that the deviation of threshold voltage of self-developed SiC MOSFETs is smaller than that of the foreign SiC MOSFETs,with a maximum discrepancy of 11％.The reason for the better performance of self-developed devices is that an appropriate amount of nitrogen is added to the SiC/SiO2 interface,which can passivate interface defects and reduce the generation of fast interface states,so that the total interface state density is minimized.
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