Cubic SiC formation on the C-face of 6H-SiC (0001) substrates

摘要

Nucleation and subsequent growth of cubic SiC (111) on Si- and C-faces of nominally on-axis 6H-SiC substrates was investigated. More uniform nuclei and twin boundary distribution was observed when 3C-SiC was grown on the C-face. This was attributed to a lower critical supersaturation ratio. A new type of defects which appear as pits in the C-face 3C-SiC layers related to homoepitaxial 6H-SiC spiral growth was found and described. The evaluation of the growth driving force for both polar faces showed that the homoepitaxial 6H-SiC spirals were not overgrown on the C-face due to low maximum supersaturation ratio. The XRD ω-rocking characterization shows a better structural quality of the 3C-SiC grown on the Si-face, however on the C-face the uniformity over the whole sample was higher. Unintentional doping by N (～10~(16) cm~(-3)) was slightly higher on the C-face while Al doping was higher (～10~(14)cm~(-3))on the Si-face of the grown material, similarly to the doping of hexagonal SiC polytypes.