Atomic-Layer Level Control in SiC Crystal Growth Using Gas Source Molecular Beam Epitaxy

Atomic-layer level control in SiC crystal growth using gas source molecular beam epitaxy was demonstrated. Alternate supply of source gases of Si₂H₆ and C₂H₂ induced the transitions of surface superstructures. When Si₂H₆ was supplied, Si atoms generated by thermal decomposition were adsorbed on a 3C-SiC (001) substrate, which brought about the change of surface superstructures from the initial c (2 × 2) to the sequential evolution of (2 × 1), (5 × 2) and (3 × 2) corresponding to the increase of constituent Si atoms. When C₂H₂ was supplied, the adsorbed Si atoms reacted with the C₂H₂ molecules, resulting in crystallization of SiC, and the superstructure showed the initial c(2×2) pattern. The growth rate seemed to be regulated by the limited number of Si atoms forming superstructures. Detailed analysis of in-situ dynamic RHEED observation revealed the proper configuration of surface superstructures, and the possibility of one-monolayer growth of 3C-SiC was discussed.