This study investigates the degradation behavior and reliability of silicon carbide (SiC) MOSFETs under power cycling tests to address their vulnerability to thermo-mechanical stresses. Five 650V SiC MOSFETs (IMW65R107M1H) were subjected to controlled thermal cycles, and key parameters such as body diode voltage, thermal resistance, and junction temperature were monitored. The degradation mechanisms, including bond wire fatigue and gate oxide defects, were identified through abrupt and gradual changes in the body diode voltage. A Weibull distribution was used to model the component lifetime, estimating a B-10 lifetime of 7279 cycles for devices with varying ∆Tj between 120 °C and 140 °C. Furthermore, the body diode voltage and gate leakage current were highlighted as effective precursors for early failure detection. This research provides insights into improving SiC MOSFET reliability and lays the groundwork for early warning systems in high-power converter applications.

The reliability of semiconductor power devices can be studied by performing a thermal and power cycling test. In order to create the desired temperature cycles, there are four free variables to select during the power cycling test, namely the heating current, heating time, cooling time, and heatsink temperature. In this paper, the relation between the selected variables and the minimum and maximum junction temperature is extensively tested for the silicon IGBT with serial number IKP06N60T. Furthermore, the thermal model is discussed and verified and a rough estimate of the electrical resistance, thermal time constant, thermal resistance, and thermal capacitance are calculated.