The nucleation and growth of thin films deposited on to carbon substrate by ion beam sputtering

Abstract

When based on the nucleation theory, the nucleation and growth of tungsten and tungsten-molybdenum films deposited on to a carbon substrate by a sputter deposition method are discussed. The experimental variations of the cluster density were measured as a function of the incident rate of sputtered atoms, nucleation rate and saturation density. On the assumption that an observable cluster in deposited films consists of single atoms and critical nuclei by capture of additional atoms, the total amount of condensation deposit has been analysed as a function of their nucleation rate and saturation density with i ∗th critical nuclei at constant high vacuum and low temperature. It was found that monolayer films consisting of a single atom and its pair or several atoms cluster are obtained at the optimum amount of incident atoms, together with a secondary electron emission dominated position at an angular distribution of the sputtered atoms. Moreover, the saturation density obtained by the diffusion distance correlates fairly well with the intrinsic granules of a substrate. The sputter deposition films of W and W-Mo obtained in this way were found to be useful for high resolution electron microscopy.