The formation of the developed nanorelief on deposited films

Abstract

A model of a film nanorelief formed upon the deposition of atomic flow on the surface is proposed. This model is based on the growth of structures formed from single atoms diffusing on the surface. The complex fractal structure of the film appears due to the formation of stable clusters that either are a result of the fluctuation formation of nucleation centers with critical sizes or they form on additive atoms that serve as nucleation centers. At high temperatures, adatoms may be transferred to hotter relief elements due to the decreasing diffusion activation energy that goes along with the increasing temperature. This promotes the formation of the film’s fractal structure. At a later stage of fractal film growth, the main growth mechanism is the diffusion-limited aggregation of deposited atoms. The size of the minimal cluster of the fractal structure is determined by the diffusion smoothing; it is equal to rmin = 2σa3/T, where ρ is the surface tension, T is the surface temperature, and a is the atomic size.