Monte Carlo Modelling of Ion-Beam-Assisted-Deposition: Application to Diamondlike Carbon

Abstract

We have performed a Monte Carlo simulation of the growth of a carbon film under ion bombardment, taking into account a preferential displacement of atoms in the film depending on their hybridization state. The size of the cascade and the number of displacements in the solid are calculated depending on the concentration in diamond-type chemical bonds (sp³) or graphite-type chemical bonds (sp²). These values are used in a Monte Carlo code which calculates the local changes in concentration in sp³ sites and sp² sites due to the effect of the cascades. The effect of the ion energy and the ratio between ions and atoms fluxes is studied. A comparison is made with experimental results where diamondlike carbon films are obtained under Ar⁺ and Xe⁺ irradiations. Good qualitative agreement is obtained between the properties of the film measured and the results of the model.