Thermally stable Operating Point for SiC MOSFETs in the Power Cycling Test

Silicon Carbide (SiC) MOSFETs are prone to a thermal runaway type failure in the power cycling test. This leads to a possible change of failure mode and may cause overestimation of power cycling lifetime using empirical models. This work examines the thermally stable operation of SiC MOSFETs in the power cycling test. A criterion for stable operation is proposed and applied to sample data. A method to assess stability form datasheet values and power cycling data without the need for special measurements is given.