Aging assessment of discrete SiC MOSFETs under high temperature cycling tests

Silicon carbide (SiC) power MOSFETs have been becoming a strong alternative to silicon (Si) technology in high-voltage, high-frequency, and high-temperature applications. Despite their growing market share, limited field information is available regarding the aging facts under thermal stress and long term reliability of discrete SiC MOSFETs. In this paper, discrete SiC devices are thermally aged through a custom designed high temperature power cycling setup controlled by TI 28335 microcontroller. On-state resistance variation of devices is continuously monitored and stored in each cycle, while other electrical parameters are captured at certain intervals by utilizing an automated curve tracer. Variation of electrical parameters throughout the cycles is presented in order to assess their correlation with the aging/degradation state of the switch. The discussions regarding aging precursors are supported by structural changes obtained through scanning acoustic microscopy (SAM) and cross-sectioning.