Physics of reconstructed silicon surfaces

Abstract

Low-indexed silicon surfaces are reconstructed, i.e. the surface unit mesh is larger than the unit mesh of an equivalent bulk lattice plane. Up to now, the surface structures observed experimentally could not be predicted from theoretical calculations. However, some of the structural proposals could be sorted out by calculating, e.g. the band structure of the electronic surface states for specific surface atomic arrangements and comparing these results with experimental data. In this paper the results for (100), (110) and (111) silicon surfaces are reviewed. New data are reported on the irreversible structural conversion of the Si(111) −2 × 1 cleavage to the stable 7 × 7 structure and on the Debye temperatures of both structures. A new model combining surface vacancies and ripple distortions is proposed for the Si(111)−7 × 7 structure. Recent cluster calculation have revealed structural parameters lor the Si(111)−2 × 1 structure by minimizing the total energy of the cluster in dependence of the position of the surface atom. These data are in good agreement with experimental values evaluated from LEED studies.