NUCLEATION OF HOMOEPITAXIAL SI CHAINS ON SI(001) AT ROOM-TEMPERATURE

Results are presented of a microscopic study of the formation of epita xial Si dimer chains. We find that dimers adsorb on a limited number o f sites only. Interactions between dimers and diffusing adatoms lead t o the formation of three-atom clusters which can be extended to dilute d lines of dimers. Only two types of lines are observed: lines along [ 110] and lines along [310]. These lines connect to each other and form a random network. Upon further deposition, the diluted dimer lines tr ansform into epitaxial dimer rows. This transition starts at the end o f the lines by reorienting the dimers in the line and adding mobile ad atoms.