BINDING-ENERGIES FOR CARBON-ATOMS AND CLUSTERS DEPOSITED ON THE SI(100) SURFACE

Binding energies of carbon atoms adsorbed on a (2 x 1) reconstructed S i(100) surface were calculated as a function of sub-monolayer coverage s. Also calculated were energies for C atoms deposited on the surface as small clusters, C-n (with n = 3 and 4). All calculations were condu cted considering a model potential function developed recently for sys tems containing C and Si atoms. For the low coverage limit (representi ng coverages up to one monolayer), carbon adatoms were considered as o ccupying only low energy surface sites. Owing to relatively large sepa rations among these sites, C-C interactions are negligible and only SI -C interactions are found to be contributing to binding energies. The lowest binding energy in this case corresponds to a coverage of theta = 0.25. In the case of small C clusters deposited on the surface, howe ver, binding energies were found to be stronger because of the increas ing importance of C-C interactions. From an energetic viewpoint, resul ts obtained in this study indicate that adsorbing C atoms on a Si(100) surface are more likely to form clusters than a layer-by-layer growth leading to a smooth and uniform surface coverage. This outcome was fo und to be consistent with various experimental results.