Ab initio theoretical study of an oxygen vacancy defect at the 4H-SiC(0001)/SiO_2 interface

摘要

In order to study the electronic structures of the SiC/SiO_2 interface, which is made by the oxidation of SiC, we constructed the structural models for the dangling-bond free interfaces of 4H-SiC/SiO_2 with the substrate orientations of (0001) and (1120). We carried out ab initio calculations to find that a stretched oxygen atom appears in the near-interface region of the SiO_2 insulator for the 4H-SiC(0001)/SiO_2 interface but not for the 4H-SiC(1120)/SiO_2 interface. We argue the origin of the experimentally found oxygen vacancy defect near the SiC(0001)/SiO_2 interface.