Influence of induced defects on the ultra thin film growth by low energy ion beam deposition

We introduce here our results of research on the initial stage of thin film formation. Carbon thin films were deposited by ion beam deposition on highly oriented pyrolytic graphite substrates. The surfaces were observed by a scanning tunneling microscope. Although defects induced by ions have different nature, they may appear as similar patterns on scanning tunneling microscope images due to induced perturbation of the partial electronic density. But by analyzing these patterns, it is possible to identify several categories of defects (adsorbed atoms, vacancies and interstitials). The role of such defects on the formation of islands was investigated. For comparison of their influence on the formation of islands, nickel thin films were grown by two methods (ion beam deposition and electron beam evaporation). It was found that ion beam was effective to raise the density of nucleation sites. And the scaling analysis of the images revealed the growth mode of a carbon thin film deposited by ion beam on graphite at 300/spl deg/C.