Application of self-consistent rate equations approach for SiC (0001) surface epitaxial growth

Abstract

A self-consistent rate equations method is applied to investigate the nucleation process in the early stage of SiC (0001) surface epitaxial growth. Si-Si, C–C and Si-C are considered to be unstable dimers and the dissociation rates are determined by their binding energies, substrate temperature and the geometry of adsorption sites of Si and C on the surface. The time evolution of monomer, dimer and stable cluster density as well as their dependences on temperature are in good agreement with KMC simulation results. A transition zone in the profiles of stable cluster density for different temperatures is observed, and this is caused by the effect of temperature on net nucleation rate of dimer, which will determine the number of cores for stable cluster. Si-Si dimer can hardly exist due to its much smaller binding energy. The formation of Si-C is prior to the formation of C–C dimer, which indicates that the stable clusters are mainly formed by the Si-C nucleation until the density of C–C is higher than that of Si-C dimer. Furthermore, for higher coverage, the density of dimer decreases with the increase of temperature, leading to the smaller saturation value of stable clusters density at higher temperature.