A novel 4H‐SiC accumulation mode MOSFET with ultra‐low specific on‐resistance and improved reverse recovery capability

Abstract

AbstractA novel 1440‐V 4H‐SiC accumulation mode MOSFET (ACCUFET) with ultra‐low specific on‐resistance and improved reverse recovery performance is proposed in this article. As for the proposed SiC ACCUFET, the channel region can be completely depleted by the P‐type heavily doped polysilicon gate to build an electron barrier and realize a normally‐off device. And a Schottky barrier diode (SBD) is integrated below the trench gates on both sides, which brings the feasibility of realizing reverse conduction function of the proposed ACCUFET. Also, the p‐shield regions under the Schottky contact metal provide a good electric field shielding effect for the gate oxide. Compared with the conventional SiC trench MOSFET, the numerical simulation results show that the specific on‐resistance (Ron,sp) of the proposed ACCUFET is reduced by more than 64%. The high‐frequency figures‐of‐merit HFOM [Ron,sp × Cgd] and HFOM [Ron,sp × Qgd] of the proposed device are improved by 53.19% and 58.74%, respectively. The reverse recovery time (trr), and reverse recovery charge (Qrr) are reduced by 23.28% and 82.73%, respectively. In addition, the results also indicate that the proposed device has a better latch‐up immunity compared with the conventional SiC trench MOSFET. The excellent device performance and the simple manufacturing process provide a good prospect for the application of the proposed device.