A New 4H-SiC Trench MOSFET With Improved Reverse Conduction, Breakdown, and Switching Characteristics

In this article, a recessed source trench silicon carbide (SiC) MOSFET with integrated MOS-channel diode (MCD) is proposed and investigated by TCAD simulations. The MCD features a short channel, and the channel length could be adjusted by varying the recessed depth. Owing to the drain-induced barrier lowering effect, a low potential barrier for electrons to flow through the JFET region to the N+ source region is formed, which successfully eliminates the bipolar degradation of the parasitic body p-i-n diode. Besides, the recessed source trench introduces an additional depletion region and homogenizes the distribution of the OFF-state electric field. As a result, a low gate-to-drain capacitance and a high breakdown voltage (BV) are obtained. Simulation results indicate that compared with the SiC trench MOSFET with integrated self-assembled three-level protection Schottky barrier diode, a 78.7% reduction in gate-to-drain capacitance and a 24.4% improvement in BV could be achieved in the proposed SiC MOSFET.