On the TCAD Modeling of Non-Permanent Gate Current Increase during Short-Circuit Test in SiC MOSFETs

Under short-circuit (SC) testing SiC MOSFETs exhibit an exceptional increase of gate current (100’s mA) which is not observed in their Si counterparts. Electro-thermal TCAD simulations are capable to accurately mimic all the details of measured gate current waveforms ( i G ) by capturing multiple physical mechanisms. One of these mechanisms is the thermionic or Schottky emission effect occurring at extreme temperatures (>1300K) for relatively thick gate oxides (>40nm). For the first time, it is proven that TCAD tunneling models, recommended for very thin oxides (<3nm), are suitable to reproduce the thermionic effect and predict i G in SiC MOSFETs under SC test.