Hybrid density functional analysis of distribution of carbon-related defect levels at 4H-SiC(0001)/SiO₂ interface

Abstract

Silicon carbide (SiC)-based metal–oxide–semiconductor devices suffer from carrier mobility degradation due to defects at the SiC/SiO2 interface. The carbon-related defects Si2>C=O and Si2>C=C<Si2 are thought to be possible origins of the defect levels. We studied the electronic structures of 4H-SiC(0001)/SiO2 interfaces with C=O and C=C defects by first-principles calculations based on hybrid density functional theory. We found that their defect levels are strongly affected by the local structures around the C=O and C=C groups, and the defect levels form a broad state distribution.