Computer simulations of surface analysis using ion beams

Irradiation by ion beams, used alone or combined with electron beams/X-rays, is in the basis of most vacuum techniques for surface analysis of materials. The ion bombardment effects in solids are however still hard to predict and consequently the ion beam techniques are less quantitative than others. Lack of proper description of some mechanisms and the large number of processes that take place concurrently during the ion beam irradiation lead to difficulties in the interpretation of the experimental data that are collected in the measurements. Computer simulations are considered a promising approach to understand the main physical and chemical phenomena, and a valuable tool in processing and interpreting the analytical data. In this review we summarize the fundamentals and the numerical approximations in modelling the characterization of solid surfaces by ion beams. The approach and the limitations of two major groups of existing codes, known as Monte Carlo and molecular dynamics techniques, are described in more detail. Special attention is paid to recent achievements in the description of phenomena that were not included in earlier stages of computer modelling, such as electron-phonon inelastic losses, bombardment enhanced diffusion and segregation, selective sputtering among others. Examples of the simulation approach to ion scattering and sputtering are given, including sputtering of oxides and multielemental targets, the sputter yield amplification effect, dynamic target modification, reactive sputtering, and shallow depth profiles. (C) 2006 Elsevier Ltd. All rights reserved.