Crystallography of the (3X3) surface reconstruction of 3C-SiC(111), 4H-SiC(0001), and 6H-SiC(0001) surfaces retrieved by low-energy electron diffraction

The drastic (3 x 3) reconstruction of 3C-SiC(111) is crystallographically determined by joint application of quantitative low-energy electron diffraction and holographic interpretation of diffraction intensities, scanning tunneling microscopy, and Auger electron spectroscopy. The reconstruction is shown to be present also on the 4H- and 6H-SiC(0001) surfaces, i.e., to be largely independent of the SiC polytype. It corresponds to a new type of semiconductor (n x n) surface restructuring characterized by a considerable reduction of surface dangling bonds. This is equivalent to a very effective passivation of the surfaces, favoring crystal growth by a step flow mechanism.