Influence of growth conditions on the growth mode and layer structure in MBE-growth of SiC on SiC(0001)

Epitaxial growth of SiC on 6H-SiC(0001) was realized between 900 and 1100 °C by means of solid-source molecular beam epitaxy (MBE). In general, results show that the growth mode is strongly influenced by the surface stoichiometry. In case of Si-stabilized surface, showing 3-fold superstructures, films grow layer-by-layer via two-dimensional nucleation even at relative low temperatures (< 1000 °C). This may be a result of significant influence of exchange between Si and C suppressing island formation. In reflection high-energy electron diffraction (RHEED) investigations differences for the growth on 3C-SiC(100) and α-SiC(0001) were obtained. The grown film structure was found to be dependent on the deposition mode. Whereas in the case of continuous deposition the films consist of a mixture of the cubic and hexagonal polytypes, films grown by an alternating supply controlled in an atomic level using surface superstructures were dominantly of hexagonal SiC. Therefore, we assume that the stabilization of a certain superstructure (which corresponds to a certain surface energy) stabilizes the nucleation of one polytype.