4H-SiC UMOSFET With an Electric Field Modulation Region Below P-Body

In this article, we investigate a novel optimized 4H-SiC U-shaped trench-gate MOSFET (UMOSFET) structure, which features an electric field modulation region below the P-body. This region consists of a p-type region and an n-type region, while the p-type region is wrapped by the n-type region. We use the p-type region to reduce the electric field at the P+ shielding layer and the gate oxide. The reduced electric field increases the breakdown voltage (BV) of the optimized UMOSFET substantially. The n-type region can also improve the ON-state characteristics of the UMOSFET. Under the combined action of the p-type region and the n-type region, the BV and figure of merit increased by 25.2% and 120.5%, respectively. Moreover, the specific ON-resistance dropped by 40.8%.