Investigation on Absorption and Diffusion of the Oxygen in the Asymmetric Face of the β-Silicon Carbide through the Born-Oppenheimer Molecular Dynamics

Abstract

Many methods had been proposed to process the β-silicon carbide, and the thermal oxidation-assisted polishing was considered as an efficient technique. The critical procedure in the thermal oxidation was absorption and diffusion process of the oxygen in the β-silicon carbide, especially in the asymmetric face. Therefore, the absorption and diffusion of the oxygen in the asymmetric face of the β-silicon carbide by born-oppenheimer molecular dynamics were studied. It could be observed from absorption and dissociation process of the O atom with the cell size that absorption of the oxygen in upper Si surface was fast, which was realized when the distance was smaller than 3Å. It could be observed from absorption and dissociation process of O atom with supercell size that absorption and oxidation for the Si surface was quickly, and steady oxide layer with silica was formed. On the contrary, absorption range of the C surface was smaller than that of the Si surface, and the surface recombination was more significant for the C surface. It could be calculated that the bond length of Si-O in the oxide layer was in the 1.65-1.77Å. The research products obtained in this study were propitious to reveal the mechanism in the thermal oxidation of asymmetric face of the β-silicon carbide with oxygen under ultra-high temperature.