Analysis of diffusion in Fe/4H-SiC by molecular dynamics method

Silicon carbide(SiC) is a hot topic in current semiconductor material research and is widely used but typically difficult to process. It was found that the interface reaction between the metal Fe and single crystal SiC contributes to the removal of single crystal SiC materials. The diffusion between the atoms of Fe and SiC is the basis of solid state mass transfer and reaction. In this paper, a series of static diffusion simulations of metal iron and SiC at different temperatures by molecular dynamics (MD) method are conducted to elucidate the mechanism of static diffusion in Fe/4H-SiC. It was found that the diffusion temperature range of iron (Fe) on the carbon face of 4H-SiC is similar to experimental results, and the thickness of the diffusion layer increases with temperature, consistent with experimental observations, verifying the accuracy of the simulation model. Based on that, a series of frictional diffusion simulations of metal iron and SiC at different speeds are carried out to elucidate the mechanism of frictional diffusion in Fe/4H-SiC. The study also indicated that frictional diffusion can occur at temperatures much lower than free interface diffusion. The friction speed has a significant impact on diffusion behavior, mainly manifested in the significantly different diffusion characteristics of carbon surfaces at different speeds. In addition, the increase in friction speed makes the diffusion zone more pronounced.