Effect of impact angle and substrate roughness on growth of diamond-like carbon films

Molecular dynamics simulations are performed to study the growth of diamondlike carbon films. The effect of impact angles on deposited film structures is quantitatively studied, the result of which shows that the transverse migration of incident atoms facilitates the film relaxation. Atomic-scale behaviors of the incident atoms are analyzed to give a clear picture of the phenomenon, through which a model concerning the transverse-migration-induced film relaxation is brought forward to elucidate the process of film relaxation. The effects of surface roughness of the substrate on the film growth process are also investigated. The evolution of microstructure and surface morphology of the film exhibits different characteristics in different stages of the deposition process. In the initial stage, the film shows a preferred growth at the valley, which results in smoothening of the film. In the later stage, the film shows a homogeneous growth mode. The film smoothening is attributed to the transverse migration of the incident atoms.