Cluster-beam deposition of thin films: A molecular dynamics simulation

Abstract

The time evolution of thin-film growth by ion cluster-beam deposition is studied using a two-dimensional molecular dynamics simulation in which it is assumed that the atomic interactions are of the Lennard–Jones form. The time-dependent local heating, atomic rearrangements, relaxation, and recrystallization of a cluster, impinging on a perfect film surface, is investigated at different cluster kinetic energies where the cluster size corresponds to 700 atoms in three dimensions. The evolving film microstructure which results when several clusters successively approach the surface is modeled. Neutral clusters which arrive with nozzle ejection velocity are found to remain almost intact during impact, producing a porous polycrystalline film. For ion cluster kinetic energy per atom in the order of the bond strength, atomic rearrangements, local heating, local melting, and succeeding recrystallization produces almost defect-free, homoepitaxial films which are densely packed.