A Split-Gate 4H-SiC MOSFET with a Raised Central Implant and a Stepped Schottky Contact

To address the tradeoff between the gate oxide electric field and specific on-resistance in split-gate 4H-SiC MOSFETs, as well as the poor reverse recovery performance of the parasitic body diode, a split-gate MOSFET with a raised central implanted region and a stepped Schottky contact is proposed. The raised central P-type implanted region reduces its restriction on the JFET current path; the integrated Schottky contact improves the third-quadrant performance, while the stepped geometry reduces the electric field near the Schottky contact region. TCAD simulation results show that, with a raised height of 0.33 μm, the proposed device achieves a specific on-resistance of 4.69 mΩ·cm² and a maximum gate oxide electric field of 2.93 MV/cm. The high-frequency figure of merit (HFOM) is reduced to 290.46 mΩ·nC, while the reverse recovery charge is reduced to 676.00 nC/cm². Compared with a conventional Schottky contact, the stepped contact reduces the electric field at the critical contact location by 62.4%. These results demonstrate that the proposed device improves the conduction, gate-charge, and reverse recovery characteristics while maintaining its breakdown capability.