Molecular dynamics simulations of multilayer homoepitaxial thin film growth in the diffusion-limited regime

Molecular dynamics (MD) simulations permit multiple-layer thin film growth to be studied in detail, using reliable interatomic potentials for fee metals from corrected effective medium theory. Results are presented for the homoepitaxial deposition of 50 monolayers on Pd(001) and Cu(001) near 0 K. We find that atoms in overhang sites are stable due to the absence of diffusion at very low temperature and the short time scale of MD simulations. This stability leads to interesting features in the film which may be observable in STM or other experiments near 0 EC. The growth behavior of the thin him changes after deposition of the first 5-10 monolayers: more overhanging atoms are present, the surface is rougher, and multiple-layer events begin to occur. The formation of large voids in the film and the mechanism of multi-atom rearrangement events which decrease the surface roughness are discussed. Several simulation parameters have been varied (e.g. deposition rate, system size, random aiming points of the deposited atoms) to study their effects on the results. There is no clear difference between Pd and Cu thin film growth near 0 K. (C) 1997 Elsevier Science B.V.