Comprehensive Assessment of Avalanche Operating Boundary of SiC Planar/Trench MOSFET in Cryogenic Applications

The avalanche ruggedness of power devices becomes a crucial issue to ensure the safe operation of the power conversion systems, particularly under the extreme temperature conditions. In this article, the avalanche capability of SiC planar/trench MOSFETs is systematically evaluated and analyzed over the temperature range of 90 to 340 K. Importantly, the essential mechanisms and temperature dependence of avalanche failure under cryogenic conditions are further explored by combining many analysis methods such as TCAD simulations, the unclamped inductive switching characterizations, and the transient junction temperature prediction. The highest avalanche energy density of 171.24 mJ/mm
²
at 90K indicates the great application potential of SiC plannar mosfet in cryogenic electronics. Moreover, the safe avalanche operation boundary (AOB) model is established over the cryogenic temperature range. The relevant analysis method and AOB model can be used to accurately evaluate and quantitatively predict the avalanche capability of SiC planar/trench mosfets for the cryogenic converter design.