Nucleation and step motion in chemical vapor deposition of SiC on 6H-SiC{0001} faces

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Abstract
Growth kinetics of SiC on 6H-SiC {0001} surfaces by a chemical vapor deposition method at 1200–1600 °C were studied. Through short-time growth experiments, nucleation, and lateral growth rate of atomic steps on the surface were investigated. On well-oriented 6H-SiC {0001} faces, the nucleus density was much higher on (0001̄) C faces than on (0001) Si faces. The polytypes of nuclei are discussed based on Raman scattering measurements. The lateral growth rate was about three orders of magnitude higher than the vertical growth rate at temperatures higher than 1400 °C. Anisotropy in lateral growth rates, higher in the 〈112̄0〉 and lower in the 〈11̄00〉 directions, was observed. With the decrease in growth temperature, the lateral growth rates significantly decreased, and the anisotropy was enhanced. On off-oriented {0001} faces, no nucleation took place at 1500 °C. Based on these results, surface diffusion of adatoms and step dynamics in SiC growth are discussed.