Monitoring the degradation of SiC MOSFETs undergoing thermo-mechanical stresses

Abstract

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.