Effects of Substrate Orientations on the Local Acceleration in Thin Film Growth: Case of Co on Al Surfaces

Using quantitative calculations, we undertook a systematic investigation of the phenomenon that a depositing atom is accelerated in the vicinity of the surface; called ‘the local acceleration’. The investigation used classical molecular dynamics (MD) simulation and focused on the case of the Co/Al system with respect to various surface orientations. An incident Co atom with 0.1 eV energy was accelerated about 1.5 » 3.5 eV in the vicinity of the Al (001) surface. Calculations with other incident energies showed that the average acceleration of the deposited atoms was nearly the same irrespective of the incident energy. The distribution of the local accelerations showed wide differences with the substrate orientation. Especially, the average local acceleration of Co atoms on an Al (111) surface had a higher value than that for (001) and (011) surfaces. The Al (011) surface showed the widest local acceleration distribution.