Model for ion-assisted thin-film densification

Abstract

A theoretical model to explain the densification of thin films by ion assistance is described. The model takes advantage of previously developed fast methods for three-dimensional Monte Carlo cascade computations and assumes a low thermal adatom mobility. It is shown that ion incorporation and recoil implantation of surface atoms lead to a film densification slightly below the surface of a growing film and that the density enhancement depends on the ability of vapor atoms to refill surface vacancies which are created by sputtering and driven-in atoms. In particular, the time-dependent mass density profiles evolving during the growth of a 600-eV, oxygen-assisted, vapor-deposited ZrO2 film has been determined and good agreement with experiment is obtained.