A process compatible SiC trench MOSFET integrated with double p+-polySi/SiC HJD for enhanced switching performance

In this article, a double polysilicon/SiC heterojunction diode (HJD) integrated SiC trench MOSFET (DHJD-TMOS) featuring an ohmic contact mesa is firstly proposed and investigated. The proposed device enables reverse current flow when the applied reverse voltage is lower than the turn-on voltage of the polysilicon/SiC HJD, achieved through precise control of the electron barrier height by optimizing the ohmic mesa width. The device architecture incorporates two key shielding features: a deep p + shield layer beneath the gate oxide and p + rings under the HJD source trenches, which collectively provide dual protection for the HJD region against high electric fields during blocking state, effectively suppressing leakage current. Comprehensive simulation results demonstrate significant performance improvements of the proposed DHJD-TMOS, including a 32 % reduction in reverse cut-in voltage and a 62 % decrease in total switching loss compared to conventional JBS-integrated MOSFETs. The high frequency figure of merits (HF-FOM) achieves an outstanding value of 64.07 mΩ⋅pF. These demonstrated device performances, as well as the good fabrication compatibility and process tolerance, making our proposed device highly attractive in future high frequency and high voltage applications.