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, others had a fine structure consisting of a number of smaller terraces. Step bunching is proposed to be responsible for such a morphology. Atomic resolution on as-grown surfaces was not attained. Flashing a sample to a temperature of 1500-1600-degrees-C produced a number of new morphological features. Among them are irregular, atomically flat terraces, many of them exhibiting 6 x 6 reconstruction, triangularly or hexagonally shaped islands and holes up to approximately 40 angstrom high/deep and dendritic depressions at the bottom of some hexagonal holes. These features are believed to be the result of sublimation.