Estimation of junction temperature at failure of SiC DMOSFETs in UIS test

Junction temperature of SiC DMOSFETs at device failure in unclamped inductive switching test has been estimated to be 960 K, and mechanism of the avalanche failure was discussed. The junction temperature was estimated from the extrapolation of temperature dependence of avalanche voltage. The estimated junction temperature was too low for SiC to behave as an intrinsic semiconductor, which suggests the failure occurred not in semiconductor, but in other materials such as oxides and electrode metals.