Study on the competitive growth mechanism of SiC polytypes using Kinetic Monte Carlo method

Abstract

The competitive growth process of the 4H and 6H polytypes of SiC is studied by a competitive Kinetic Monte Carlo model(KMC), which takes the atoms of silicon and carbon as the elementary kinetic particle to fully account for the interaction energy between atoms. In the competitive KMC model, the crystal lattices of two polytypes are represented by a structured mesh which fixed the site positions at the perfect crystal lattice positions. Kinetic events with competitive growth, such as deposition, diffusion are considered in physical criterion in the model. Moreover, the model not only considers the interaction energy between the same kind of atoms (Si-Si), but also considers the interaction energy between different types of atoms (Si-C). Based on the KMC model, the effects of growth conditions on the competitive growth of 4H- and 6H- SiC were studied. The competitive KMC simulation results show that the higher temperature and the larger proportion of Si source in the mixture will promote the preferential growth of 6H polytype during competitive growth. Meanwhile, with the increase of temperature and Si/C ratio, the phenomenon of atom aggregation growth on crystal surface becomes more and more obvious.