Investigation of Turn-Off dv/dt controllability in ultrahigh-voltage SiC P-IGBTs

Abstract This paper investigates the turn-off dVCE/dt controllability of an ultrahigh-voltage SiC P-IGBT. Both simulation and experimental analyses of the inductive-load turn-off process of the SiC P-IGBT were conducted with different gate resistances. Meanwhile, experimental and TCAD simulation results reveal a turn-off dVCE/dt uncontrollability at low Rg. The mechanism is attributed to the collector-gate displacement current, which modulates the Miller voltage relative to the threshold voltage, thereby controlling the turn-off dVCE/dt. When the Miller voltage drops below the threshold voltage, the MOS channel turns off during the Miller plateau. As a result, additional hole and electron injection into the drift region is eliminated, and the turn-off dVCE/dt becomes approximately constant. As Rg increases, the Miller voltage exceeds the threshold voltage, enabling MOS channel turn-on and enhanced hole and electron injection that slows depletion region expansion, thereby showing controllable turn-off dVCE/dt.