Cubic SiC formation on the C-face of 6H–SiC (0 0 0 1) substrates

Abstract

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 (∼1016cm−3) was slightly higher on the C-face while Al doping was higher (∼1014cm−3) on the Si-face of the grown material, similarly to the doping of hexagonal SiC polytypes.