SCANNING-TUNNELING-MICROSCOPY ON THE 6H SIC(0001) SURFACE

Scanning tunnelling microscopy in UHV has been used to study hexagonal (6H) silicon carbide grown by the original Lely method. The (0001BAR) C face of as-grown samples revealed extended, up to 1500 angstrom high , terraces with straight edges. Some terrace risers were smooth, other s had a fine structure consisting of a number of smaller terraces. Ste p bunching is proposed to be responsible for such a morphology. Atomic resolution on as-grown surfaces was not attained. Flashing a sample t o a temperature of 1500-1600-degrees-C produced a number of new morpho logical features. Among them are irregular, atomically flat terraces, many of them exhibiting 6 x 6 reconstruction, triangularly or hexagona lly shaped islands and holes up to approximately 40 angstrom high/deep and dendritic depressions at the bottom of some hexagonal holes. Thes e features are believed to be the result of sublimation.