The atomic structure of silicon rich SiC(00•1) surfaces of the 6H polytype was studied for the first time by scanning tunnelling microscopy in ultra-high vacuum. The surface exhibited a hexagonal arrangement with one adatom per unit cell which was identified as a SiC(00•1)3 x 3-Si reconstruction. The reconstruction could be reproducibly prepared in the ultra-high vacuum by annealing a sample under silicon flux at temperatures in the range 850–1100C. Surplus silicon did not affect the surface structure and epitaxially aggregated into large islands which have the same orientation as the substrate. Occasionally a Si(111)7 x 7 reconstruction could been observed on top. A novel model of the SiC(00•1)3 x 3-Si structure was proposed. The unit cell was suggested to consist of 11 Si atoms which were situated in two layers. Their bonding produces three dimers and three rest atoms in the first layer, and one adatom in the second layer. In the first layer, bonding of dimers and rest atoms builds nine- and six-atom rings, which surround unoccupied sites of the outermost silicon atoms of the SiC substrate. A unit cell contains three dangling bonds, one of which was associated with an adatom and was responsible for 3 x 3 protrusions, and the other two were associated with silicon atoms of the substrate.

SiC(0001)3 x 3-Si Surface Reconstruction - a New Insight with a STM. M.A.Kulakov, G.Henn, B.Bullemer: Surface Science, 1996, 346[1-3], 49-54