Theoretical investigation of vacancy related defects at 4H-SiC(000$\bar{1}$)/SiO$_2$ interface after wet oxidation

TL;DR

This study uses first-principles calculations to analyze how wet oxidation influences vacancy-related defect formation at the 4H-SiC/SiO2 interface, revealing mechanisms involving hydrogen termination and defect generation.

Contribution

It provides a detailed theoretical understanding of defect formation mechanisms at the 4H-SiC/SiO2 interface after wet oxidation, highlighting the role of vacancies and antisites.

Findings

Vacancy formation energies align with experimental defect densities.

Hydrogen termination influences defect generation pathways.

Carbon and silicon vacancies are key to defect mechanisms.

Abstract

The stability and formation mechanism of the defects relevant to silicon and carbon vacancies at the 4H-SiC(000$\bar{1}$)/SiO$_2$ interface after wet oxidation are investigated by first-principles calculation based on the density functional theory. The difference in the total energy of the defects agrees with the experimental results concerning the dencity of defects. We found that the characteristic behaviors of the generation of defects are explained by the positions of vacancies and antisites in the SiC(000$\bar{1}$) substrate and that the formation of silicon and carbon vacancies is relevant to the generation mechanism of defects. The generation of silicon and carbon vacancies is attributed to the termination of dangling bonds by H atoms introduced by wet oxidation, resulting in generation of carbon-antisite--carbon-vacancy and divacancies defects in wet oxidation.