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

A 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 x Cgd] and HFOM [Ron,sp x 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. A 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. 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 x Cgd] and HFOM [Ron,sp x 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.image