Diffusion interaction of growth steps in vacuum deposition

The interaction of two straight parallel growth steps under saturation conditions was studied using a modified Langmuir adsorption model. It is shown that as the growth steps approach each other, the rate of their motion decreases, which explains the effect of hindered coalescence of condensate islands during vacuum deposition with layer-by-layer filling of atomic layers. The cause of this phenomenon is found to be the overlap of surface diffusion layers which are a source of material for the growth steps. Features of surface diffusion and nucleation under conditions close to the saturation conditions are determined. It is shown that the nucleation of islands of a new atomic layer at supersaturation and the nucleation of islands of vacancies in the underlying layer at unsaturation are asymmetric. The results can be used to develop a technology to produce thin films by vacuum deposition.