Effects of point defects on oxidation of 3C-SiC

TL;DR

This study uses molecular dynamics simulations to explore how implantation-induced point defects affect the oxidation process of 3C-SiC, revealing that defects generally accelerate oxidation but can also cause deceleration in specific regions.

Contribution

It provides new insights into the role of different point defects on SiC oxidation, especially highlighting the complex effects within grain boundary regions.

Findings

Point defects increase oxidation rates in crystalline SiC.

Si antisites and vacancies have similar acceleration effects.

C antisites can decelerate oxidation in grain boundary regions.

Abstract

The influence of implantation-induced point defects (PDs) on SiC oxidation is investigated via molecular dynamics simulations. PDs generally increase the oxidation rate of crystalline grains. Particularly, accelerations caused by Si antisites and vacancies are comparable, and followed by Si interstitials, which are higher than those by C antisites and C interstitials. However, in the grain boundary (GB) region, defect contribution to oxidation is more complex, with C antisites decelerating oxidation. The underlying reason is the formation of a C-rich region along the oxygen diffusion pathway that blocks the access of O to Si and thus reduces the oxidation rate, as compared to the oxidation along a GB without defects.