Vapor Deposition Growth of SiC Crystal on 4H-SiC Substrate by Molecular Dynamics Simulation

Abstract

Due to the lack of appropriate experimental methods for imaging the evolution of the microstructure of materials at the growth conditions, our understanding of the physical behavior of crystal growth and defect formation during the vapor deposition growth of SiC crystals is still rather limited. In the present work, the vapor deposition growth of SiC crystal on a 4H-SiC substrate has been investigated by the molecular dynamics (MD) computer simulation method. Three different lattice planes of 4H-SiC ((0001), (112-0) and (1-100)) were selected as the surface of the substrate, and three different temperatures for substrate (2200 K, 2300 K and 2400 K) were used in growth simulations. The characteristics of the formation of different polytypes of SiC and dislocations in the grown crystals were examined. The results show that the SiC crystals were grown by a subsurface nucleation and growth mode in the vapor deposition process. For substrates with (0001) plane as the surface, the 3C-SiC single crystal was obtained in the deposited thin film. For substrates with (112-0) or (1-100) plane as the surface, the 4H-SiC single crystal was obtained instead. The temperature of the substrate was found to have a significant effect on the dislocation density generated in the grown crystals. The mechanism for the formation of Frank partial dislocations during the growth of SiC crystals has been analyzed, for which the importance of the diffusivity of atoms on the surface layer in growth has been highlighted, and it gives a good explanation of the temperature effect on dislocation formation in the grown crystals. These results can be helpful for experimental vapor deposition growth of SiC single crystals and epitaxial layers of high quality.