SCANNING TUNNELING MICROSCOPY AND SPECTROSCOPY OF CUBIC BETA-SIC(111) SURFACES

Scanning tunneling microscopy (STM) images show a 6 x 6 reconstruction of the beta-SiC(111) surface annealed at 1150-1200-degrees-C. Contrast reversal is observed as tunneling voltage bias is reversed. Spectroscopic I/V data indicate the presence of a graphite layer on the top surface. A model of the surface is proposed where an incommensurate graphite monolayer is grown over a (1 x 1) Si-terminated beta-SiC(111) surface. This model helps to explain the discrepancy between the 6 square-root 3 x 6 square-root 3 geometry observed by LEED and the 6 x 6 geometry observed by STM on the same surface.