Atomic structure of the steps on Si(001) studied by scanning tunneling microscopy

We have studied atomic structures of the steps on Si(001) surface, using scanning tunneling microscopy. Freezing of dimer buckling on an upper terrace near the S-A steps is clearly observed, which also affects atomic arrangements near the step. Both types of the rebonded and the nonrebonded S-B steps are observed. The scanning tunneling microscopy image of the rebonded S-B step shows a characteristic feature in which two markedly bright spots are observed in the empty state, It is found that one bright protrusion corresponds to the dimer at the end of the upper terrace, and another corresponds to the rebonded atoms at the lower terrace. The feature might be related to the lattice strain and the charge transfer by the rebonding. (C) 1996 Vacuum Society.