4H-SiC Trench MOSFET with Integrated Heterojunction Diode for Optimizing Switching Performance

In this study, a novel 4H-SiC Trench MOSFET with integrated heterojunction diode at the bottom of gate trench is proposed (HJD-TMOS) and investigated by TCAD simulation. The integrated heterojunction diode operates as a freewheeling diode in reverse conduction, which significantly reduces reverse recovery charge (Q
rr
) and reverse turn-on knee voltage (V
on
) more than 2 times, compared with conventional SiC trench MOSFET (C-TMOS) while maintaining almost the same threshold voltage and breakdown voltage. Moreover, due to the shielding effect of polysilicon below the gate, the gate to drain charge (Q
gd
) decreases by 68%, in comparison with C-TMOS. Therefore, the HJD-TMOS is a potential choice for high frequency, high efficiency applications.