Heterojunction diode shielded SiC split-gate trench MOSFET with optimized reverse recovery characteristic and low switching loss

Abstract

A split-gate SiC trench MOSFET with a hetero-junction diode (HJD) is proposed and numerically analyzed in this paper. The proposed structure features the HJD to effectively suppress the turn-on of the parasitic body diode and reduce the depletion region in the JFET area. A P+ shielding layer surrounding the HJD and the gate oxide layer is used to alleviate the concentration of the electric field under the gate trench and improve the switching performance. As a result, not only the breakdown voltage is increased by 20.8% at the same level of the on-state resistance but also the miller charge and the switching loss of the proposed structure are reduced by 52% and 39.1%, respectively when compared with those of the conventional SiC trench MOSFET.