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

Nucleation and subsequent growth of cubic SiC (1 1 1) 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 (∼1016 cm−3) was slightly higher on the C-face while Al doping was higher (∼1014 cm−3) on the Si-face of the grown material, similarly to the doping of hexagonal SiC polytypes.

► Growth of cubic SiC on Si- and C-faces of 6H–SiC.
► New defects, pits, with 6H–SiC spiral appear in the 3C–SiC layer grown on the C-face.
► Lower supersaturation ratio results in pits formation.
► Higher quality 3C–SiC on Si-face, higher uniformity over the sample on the C-face.
► N doping higher and Al lower on C-face, similarly to doping in hexagonal polytypes.