Short-circuit failure mechanism of SiC power MOSFETs

Abstract

Failure mechanisms during short-circuit conditions of Silicon Carbide Power MOSFETs are analysed in this work, and a possible theoretical explanation is provided. Insight into the physics involved in such processes was inferred through experimental and numerical analyses. The TCAD structure used for electro-thermal simulations was calibrated to fit the I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</sub> -V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GS</sub> characteristics of a commercial device. Adequate physical effects were considered, such as the presence of charges and traps at the oxide-SiC interface and their effect on threshold voltage and carrier mobility. Experimental evidences were explained by analyzing the numerical results. The high temperature reached during these operating conditions was addressed as the main cause of the device failure. The effect on the leakage current and the activation of a parasitic bipolar transistor are also shown.