MOLECULAR-DYNAMICS STUDY OF FILM GROWTH WITH ENERGETIC AG-ATOMS

Three-dimensional molecular-dynamics simulation of the growth of silver (Ag) atoms on an Ag (111) oriented substrate has been conducted as a function of incident atom energy and temperature. Incident atom energies of 0. 1 eV per atom resulted in the formation of epitaxial islands that coalesced to form a continuous thin film. Increasing the incident atom energy promoted layer-by-layer growth, and with an incident atom energy of 10 eV per atom the film growth was nearly layer-by-layer. For the 10-eV incident atom energy with a 330-K substrate temperature a small amount of interface mixing was observed, but the mixing was eliminated by lowering the substrate to 30 K. The interface mixing process occurred by an exchange process between the energetic atom and a surface atom. Increasing the incident atom energy to 20 eV per atom increased the amount of interface mixing, but the interface mixing could not be eliminated by lowering the temperature of the substrate. This indicates that the mixing process is ballistically activated and thermally assisted. Increasing the incident atom energies to 40 eV per atom resulted in the mixing extending to the second layer of substrate atoms; however, the mixing was found to occur by multiple unrelated exchanges between adjacent layers. All deposited atoms were observed to form epitaxial layers; although stacking faults were observed.