Atomic and electronic properties of different types of SiC/SiO2 interfaces: First-principles calculations

Abstract

The atomic and electronic properties of different types of SiC/SiO2 interfaces were investigated by using the first-principles method. Considering the four different terminal types on the SiO2 side and the two different crystal faces of 4H-SiC, we constructed eight different SiC/SiO2 interface models. Among the four different SiC/SiO2 interface structures with dangling bonds, the interface structures with Si dangling bonds will generate defect states at the center of the band gap and the conduction band edges, while the interface structures with C dangling bonds will create defect states at the valence band edges. The band alignment of four different SiC/SiO2 interface structures without dangling bonds indicates that the O-terminated interface structures have higher conduction band offsets than the Si-terminated interface structures. Besides, the O-terminated interface structures without dangling bonds have significantly higher interface separation work and are more favorable than the other interface structures, which can better resist leakage current and have the higher quality in SiC-based MOSFET applications.