MOLECULAR-DYNAMICS SIMULATION OF THE ENERGETIC DEPOSITION OF AG THIN-FILMS

A three-dimensional molecular-dynamics simulation of the growth of 500 energetic Ag atoms incident on a substrate with 1008 Ag atoms was conducted with the atomic interactions modeled by the embedded-atom method. The substrate temperature was 300 K and incident-Ag-atom energies ranged from 0.1 to 10 eV. For all incident-atom energies the growth was epitaxial. For low incident-atom energies the surface topography was three-dimensional islands, but the growth changed progressively towards layer-by-layer (Frank-van der Merwe) growth as the incident-atom energy increased to 10 eV. At low incident-atom energy (0.1 eV) the primary mechanism for redistribution of atoms between layers of the film was the collapse of unstable configurations of atoms. For higher incident-atom energies (1.0 and 10.0 eV) the primary redistribution mechanism was ballistic displacement. At low fractional layer coverage, both perfect-crystal and stacking-fault sites were occupied; for larger layer coverage, however, all of the atoms in a single layer tended to occupy one type of site, although both perfect and stacking-fault layers were observed.