4H-SiC superjunction MOSFET with integrated high-K gate dielectric and split gate

Abstract A 4H-SiC superjunction (SJ) MOSFET (SJMOS) with integrated high- K gate dielectric and split gate (HKSG-SJMOS) is proposed in this paper. The key features of HKSG-SJMOS involve the utilization of high- K (HK) dielectric as the gate dielectric, which surrounds the source-connected split gate (SG) and metal gate. The high- K gate dielectric optimizes the electric field distribution within the drift region, creating a low-resistance conductive channel. This enhancement leads to an increase in the breakdown voltage (BV) and a reduction in the specific on resistance ( R on,sp ). The introduction of split gate surrounded by high- K dielectric reduces the gate−drain capacitance ( C gd ) and gate−drain charge ( Q gd ), which improves the switching characteristics. The simulation results indicate that compared to conventional 4H-SiC SJMOS, the HKSG-SJMOS exhibits a 110.5% enhancement in figure of merit (FOM, FOM = BV 2 / R on,sp ), a 93.6% reduction in the high frequency figure of merit (HFFOM) of R on,sp · C gd , and reductions in turn-on loss ( E on ) and turn-off loss ( E off ) by 38.3% and 31.6%, respectively. Furthermore, the reverse recovery characteristics of HKSG-SJMOS has also discussed, revealing superior performance compared to conventional 4H-SiC SJMOS.