In situ Degradation Monitoring of SiC MOSFET Based on Switching Transient Measurement

Abstract

This paper presents an silicon carbide (SiC) MOSFET health condition monitoring method based on the switching transient measurements. Specifically, the device's turn -on time is used as the aging precursor, and a detection circuit is developed with picosecond resolution to detect the variations of the turn -on time. For this purpose, power cycles with constant junction temperature swings are applied on sample devices to accelerate their thermally triggered degradation. Over the aging process, device parameters are measured periodically using automated curve tracer to observe degradation-related changes. Also, a double pulse tester is used to evaluate devices’ switching transient changes throughout aging. Based on these results, both the theoretical discussions and experimental results imply that device turn -on time is a viable aging precursor and can be used to monitor device health at system start-up. High-resolution capture module of readily available system microcontroller is employed to measure the turn -on time through a simple auxiliary interface circuit on a buck converter. Experimental results show that onboard device aging can successfully be achieved during systems start-up in the order of microseconds.