High-temperature nucleation of cubic silicon carbide on (0001) hexagonal-SiC nominal surfaces

The development of 3C-SiC crystals from (0001) oriented hexagonal seed has always suffered from systematic twinning that appears during the nucleation step of the layer. To investigate the possibility to reduce or eliminate the incoherent twin boundaries at high temperature (for conditions close to bulk growth ones), we conducted an experimental study on 3C-SiC nucleation. A mechanism for the selection of one 3C-SiC orientation among the two possible is proposed. It is based on a strong interaction between the R-SiC substrate steps and the anisotropic lateral expansion of the beta-SiC domains. This model is confirmed by cross-sectional high resolution transmission microscopy observations of the alpha-beta interface. The mechanism is discussed with respect to the surface polarity (Si or C faces), the miscut angle, and the substrate polytype.