Governing factors for the formation of SiC polytypes and dislocations during SiC crystal growth: An atomistic computational approach

Abstract

The effects of various process variables on the formation of SiC polytypes and dislocations during SiC crystal growths have been investigated using atomistic simulations based on an empirical potential (the second nearest-neighbor MEAM) and first-principles calculation. It is found out that the main role of process variables (temperature, surface type, growth rate, atmospheric condition, dopant type, etc.) is not to directly change the relative stability of SiC polytypes and the formation of dislocations but to change the formation tendency of point defects. The biaxial local strain due to the formation of point defects is found to have an effect on the relative stability of SiC polytypes and formation of dislocations and is proposed as a governing factor that affects the selective growth of SiC polytypes and the formation tendency of dislocations. Based on the present local strain scheme, the competitive growth among SiC polytypes and the formation tendency of dislocations available in literatures can be reasonably explained by interpreting the effect of each process variable in terms of defect formation and the resultant local strain. Those results provide an insight into the selective growth of SiC polytypes and the suppression of dislocations and also help us obtain high quality SiC single crystals.