INFLUENCE OF RECONSTRUCTION ON THE INITIAL STAGES OF SILICON MOLECULAR BEAM EPITAXY.

High energy ion scattering channeling and low energy electron diffraction are used for an investigation of the initial stages of interface formation during Si homoepitaxy. We find a strong dependence of the atomic reordering - a necessary condition for pseudomorphic growth - on substrate surface, deposition temperature and Si coverage: (1) Si deposition at 300 K reorders the Si(100) substrate reconstruction in a layer by layer manner. In contrast Si(111) is unaffected by Si deposition at that temperature. This difference between Si(100) and Si(111) can be understood in terms of different structural models. (2) On both surfaces deposition at 300 K results in a disordered overlayer. (3) As a direct consequence of the dependence of the reordering on reconstruction we find a lower epitaxial temperature ( approximately equals 570 K) for Si(100) than for Si(111) ( approximately equals 790 K).