Investigation and Comparison of Temperature-Sensitive Electrical Parameters of SiC mosfet at Extremely High Temperatures

Due to the excellent silicon carbide (SiC) material characteristics, SiC MOSFETs can operate at extremely high temperatures and can be used in harsh environment applications. In this case, it is crucial to ensure the reliability of the power electronic systems. The temperature-sensitive electrical parameters (TSEPs) have been used for online junction temperature monitoring to monitor the health condition of the SiC MOSFET at lowtemperatures (<175 degrees C). However, the performance of the TSEPs at extremely high temperatures is still unknown, and the influence of temperature on the TSEPs of SiC MOSFETs at extremely high temperatures is unclear. In this article, the theoretical mechanisms of the impact of the extremely high temperature on TSEPs are investigated in detail. In particular, the different effects of high temperature on the turn- ON delay time and turn- OFF delay time are discussed carefully. Based on the proposed high-temperature characteristic test method, the TSEPs of SiC MOSFET (including static and dynamic characteristics) are tested and analyzed comprehensively from room temperature to 375 degrees C. And the sensitivity and linearity of the TSEPs in different temperature ranges are analyzed and compared. According to the results, threshold voltage and turn- OFF delay time are the two TSEPs with good sensitivity and linearity over a wide temperature range (from room temperature to 375 degrees C). And the linearity of the turn- OFF delay time is the best among all TSEPs over a wide temperature range.