Exploring SiC planar IGBTs towards enhanced conductivity modulation comparable to SiC trench IGBTs

Abstract

The state-of-the-art silicon insulated-gate bipolar transistor (IGBT) features a trench gate, since it enhances the conductivity modulation. The SiC trench IGBT, however, faces the critical challenge of a high electric field in the gate oxide, which is a crucial threat to the device’s reliability. In this work, we explore the possibility of using a SiC planar IGBT structure to approach high performance to the level of a SiC trench IGBT, without suffering the high gate oxide field. The proposed SiC planar IGBT features buried p-layers directly under the p-bodies, and thus can be formed using the same mask set. The region between the buried p-layer and the p-body is heavily doped with n-type dopants so that the conductivity modulation is improved. Comprehensive TCAD simulations have been carried out to verify this concept, and the simulation results show the new SiC planar IGBT exhibits a high performance comparable to the trench IGBT, and also exhibits a low gate oxide field.