In this paper, a novel asymmetric trench SiC MOSFET with a Poly-Si/SiC heterojunction diode (HJD-ATMOS) is designed to improve its reverse conduction characteristics and switching performance. This structure features an integrated heterojunction diode, which improves body diode characteristics without affecting device static characteristics. The heterojunction diode acts as a freewheeling diode during reverse conduction, reducing the cut-in voltage (Vcut-in) to a lower level than conventional asymmetric trench SiC MOSFET (C-ATMOS), while maintaining a similar breakdown voltage. Meanwhile, the split gate structure reduces gate-to-drain charge (Qgd). Through TCAD simulation, the HJD-ATMOS decreases Vcut-in by 53.04% compared to the C-ATMOS. Both Qgd and switching loss are reduced, with a decrease of 31.91% in Qgd and 40.29% in switching loss.
Keywords: asymmetric trench MOSFET; heterojunction; low cut-in voltage; silicon carbide; switching loss.