Computer simulation of ionized cluster beam bombardment on a carbon substrate

Using the time-evolution Monte Carlo simulation code DYACAT, the collisional phase of thin-film growth by ionized cluster beam deposition has been investigated. In the DYACAT program, which is based on the binary collision approximation, trajectories of ions and recoil atoms are followed dynamically. In order to overcome the difficulties of the binary collision approximation of a low-energy projectile, many-body encounters are numerically solved by the molecular dynamics method, where a projectile collides at the same time with many atoms within its collision diameter. An ionized (Ag)n cluster beam (n=100-500) is bombarded onto an amorphous carbon surface. The migration of Ag atoms on the surface and the angular distribution of Ag atoms are calculated. It is found that the mechanism of ionized cluster beam deposition can be divided into three stages, i.e., high surface density formation, reflection due to the high surface density and collisional spikes in the cluster due to the collision between virgin atoms in the upper part of the cluster and reflected atoms from the dense surface. (orig.)