A New SiC Split-gate MOSFET Structure With Protruded P-base and the Mesa above JFET for Improving HF-FOM

Abstract

A novel 4H-SiC MOSFET (PM-MOSFET) for rated 3.3 kV applications is proposed, which features the protruded P-base and the mesa above JFET. Numerical simulation based on Silvaco is carried out to investigate the benefits of the proposed structure. The on-state resistance of PM-MOSFET is 11.9 mΩ·cm2, which is dramatically lower compared to on-resistance of 18.2 mΩ·cm2 of the traditional split-gate MOSFET (SG-MOSFET). The Crss of SG-MOSFET extracted at Vd = 1800 V is 17.5 pF/cm2, while the Crss of PM-MOS extracted is 6.5 pF/cm2, which is three times lower than that of the SG-MOSFET. It is demonstrated that the PM-MOSFET structure is superior to the SG-MOSFET. More importantly, the benefits above are achieved without degradation of other performances of MOSFET. As a result, the PM-MOSFET presents superior figure of merit ( HF-FOM) (Ron × Crss) than that of the SG-MOSFET. The PM-MOSFET achieves much faster switching speed than the SG-MOSFET.