An Online Gate Oxide Degradation Monitoring Method for SiC MOSFETs Based on Turn-ON Gate Current Change Rate

Gate oxide degradation (GOD) presents a reliability issue for silicon carbide metal-oxide-semiconductor field-effect transistors, especially under high-temperature and high-electric-field conditions. This letter proposes an online condition monitoring method based on the peak value of the turn-ON gate current change rate (di _g/dt _,max). The technique utilizes a noninvasive PCB Rogowski coil to measure di _g/dt _,max, demonstrating high practicality. Accelerated aging tests under positive and negative high-temperature gate bias and high-temperature gate switching conditions reveal correlations between di _g/dt _,max and GOD, with variations of 5.61%, 5% and 8.33%, after 160 h of aging. Double pulse test (DPT) results indicate that di _g/dt _,max is independent of external factors, such as temperature, drain-source voltage (V _ds), drain current (I _ds) and package aging. Results from a buck converter further validate the feasibility of long-term online monitoring.