Characterization of Interface Traps in SiO$_2$/SiC Structures Close to the Conduction Band by Deep-Level Transient Spectroscopy

TL;DR

This study investigates interface traps in SiO$_2$/SiC structures using deep-level transient spectroscopy, revealing how oxidation atmosphere and crystal face influence trap densities and types, with implications for device performance.

Contribution

It provides detailed characterization of interface traps in SiO$_2$/SiC, highlighting the effects of oxidation atmosphere and crystal face on trap generation and elimination.

Findings

High density of $C1$ traps around 0.16 eV in low-mobility interfaces.

Wet oxidation eliminates $C1$ traps on C-face.

$O2$ traps observed only on Si-face interfaces.

Abstract

The effects of the oxidation atmosphere and crystal faces on the interface-trap density was examined by using constant-capacitance deep-level transient spectroscopy to clarify the origin of them. By comparing the DLTS spectra of the low-mobility interfaces oxidized in a N$_2$O atmosphere with those of the high-mobility interfaces on C-face oxidized in a wet atmosphere, it was found that a high density of traps are commonly observed around the energy of 0.16 eV from the edge of the conduction band ($C1$ traps) in low-mobility interfaces irrespective of crystal faces. It was also found that the generation and elimination of traps specific to crystal faces: (1) the $C1$ traps can be eliminated by wet oxidation only on the C-face, and (2) the $O2$ traps (0.37 eV) can be observed in the SiC/SiO$_2$ interface only on the Si-face. The generation of $O2$ traps on the Si-face and the elimination of $C1$ traps on the C-face by wet oxidation may be caused by the oxidation reaction specific to the crystal faces.