Relationship between growth conditions, thermodynamic properties and crystal structure of SiC

The growth of certain SiC polytypes in the molecular beam epitaxy (MBE) was analysed within the framework of classical thermodynamic nucleation theory. It is demonstrated that the formation of certain polytypes in the nucleation stage is due to a complex interplay between their differences in the surface and formation energy as well as the growth conditions. Based on these considerations, the estimations clearly indicate that the formation of the 3C-SiC polytype is preferred at Si-rich conditions or low temperatures, whereas the hexagonal polytypes occur at C-rich conditions or higher temperatures in agreement to experimental findings.