STM STUDY OF THE SIC(0001)ROOT-3X-ROOT-3 SURFACE

We have used scanning tunnelling microscopy to study the root 3 x root 3 reconstruction of the Si-terminated 6H-SiC(0001) surface. We find t hat the images are consistent with a structural model composed of 1/3 layer of Si or C adatoms in threefold-symmetric sites on top of the ou termost Si-C bilayer, similar to the reconstructions observed for 1/3 monolayer of e.g. group-III metals on the Si(111) surface. Additionall y, we discuss the nature of the most frequently occurring defects on t he root 3 X root 3 surfaces as well as the stacking sequence of the at omic layers below the reconstructed surface layer.