A Temperature-Independent Gate-Oxide Degradation Monitoring Method for Silicon Carbide Metal Oxide-Semiconductor Field-Effect Transistors Based on Turn-Off Ringing

Gate-oxide degradation in silicon carbide (SiC) metal oxide-semiconductor field-effect transistors (MOSFETs) is a significant concern. Consequently, several methods have been developed to monitor the aging degree. In this article, a temperature-independent method for gate-oxide degradation monitoring is proposed by measuring the minimum turn-off circuit parasitic inductor voltage vcir_min at a specific gate resistor and voltage. The temperature sensitivity of vcir_min is analyzed based on a derived model. Adjustment of the turn-off gate voltage and resistance is proposed to mitigate the impact of temperature on vcir_min. The devices under test are aged by high-temperature gate bias (HTGB) experiments and are tested in double-pulse tests (DPT). A 32 V bias for 42 h and 25-150 degrees C temperature results in changes of 6.55% and 0.103% in vcir_min, respectively. The experimental results show that the proposed method is effective in maintaining temperature independence. Additionally, the effects of bus voltage, load current, and bond wire failure on vcir_min are also tested and analyzed. The proposed method provides a valuable tool for accurately monitoring SiC MOSFET gate-oxide degradation in scenarios characterized by significant temperature fluctuations.