Growth mechanisms of Si and Ge epitaxial films on the dimer reconstructed Si {100} surface via molecular dynamics

Microscopic and macroscopic growth mechanisms of thin epitaxial films due to Si and Ge deposition on the Si{l00}-(2X 1) surface are studied via molecular dynamics using Tersoffs many-body potential. The dimer openings on the reconstructed surface following the Si or Ge deposition are either due to a diffusing adatom induced mechanism or due to a direct insertion of the incoming adatoms into the epitaxial positions. Two distinct layer by layer growth modes of macroscopic epitaxial films are observed; (a) the mode in which the domains of good or bad epitaxial growths remain roughly in the same area of the interface throughout its entire thickness, and (b) the mode in which reconstructions on the buried interfaces can be relieved by long time equilibrations, i.e., the epitaxially deposited film can heal its inner layers during equilibrations. The qualities of the final macroscopic films in these two cases are found to be distinctively different.