NEW DEVELOPMENT IN THE THEORY OF MBE GROWTH OF SI - A CONFRONTATION WITH EXPERIMENT

The current understanding of the DC resistive heating effects in annealing of Si is outlined. The hypothesis of electromigration of Si adatoms and surface vacancies is shown to provide grounds for three different mechanisms of step bunching operating in different temperature intervals. The anisotropy of the surface diffusion on (001)Si, proven by the selective nucleation effect, is essential for the formation of predominant reconstruction domains during DC annealing. The mechanisms of the reported step bunching at a single domain (001)Si surface are, however, still unclear. In the absence of DC heating one can study some features of the undisturbed processes of MBE growth of Si. The anisotropy of the crystallization (and evaporation) kinetics at the steps causes a formation of double height steps when the surface processes are controlled by the adatom incorporation in the crystal (surface diffusion is comparatively fast). That is why formation of a single domain surface (in the absence of DC heating) can be expected in a limited range of growth and evaporation conditions.