Dynamic reflection high-energy electron diffraction observation of 3C-SiC(001) surface reconstruction under Si₂H₆ beam irradiation

The transition of 3C-SiC(001) surface superstructures under Si ₂H₆ gas molecular beam irradiation was dynamically observed by reflection high-energy electron diffraction. Starting from the C-terminated c(2×2) structure, the surface structure changed in the order of c(2×2)→(2×1)→(5×2)→(3×2) with continuing irradiation. The amounts of Si₂H₆ dose required for the transitions c(2×2)→(5×2) and c(2×2) →(3×2) were approximately 1.16 and 1.36 times as much as that for c(2×2)→(2×1). These ratios are interpreted as the relative amount of the constituent Si atoms of the superstructures. This experimental result supports the simple dimer model for (2×1) (1 monolayer of Si) and the additional dimer model for (5×2) (1.2 monolayer) and (3×2) (1.33 monolayer), respectively, as the proper configurations of these surface superstructures.