Advanced Monte Carlo Simulations for Ion-Channeling Studies of Complex Defects in Crystals

This chapter describes the most important features of computational software called ‘McChasy’, which is a Monte Carlo (MC) simulation code developed for the evaluation of the Rutherford Backscattering Spectrometry data, in particular, recorded in the channeling mode (RBS/C). RBS/C is an experimental technique used in the analysis of defects in single crystals. Lattice distortions affect materials modified by ion beams or exposed to irradiation. Therefore, the analysis of damage in crystals is of high importance in materials science. Various types of defects can be created due to the interaction of ions with targets. However, RBS/C has different sensitivity to each of them so the analytical analysis of experimental data is hardly possible. MC simulations are a powerful tool used to overcome this limitation. The McChasy code simulates the movement of light ions in crystals. The software provides a fitting procedure of RBS/C spectra based on independent depth profiles of different defect types: interstitials, edge dislocations, substitutions, stacking faults or grain boundaries. The code works well not only with materials containing complex defects but also with heterostructures and superlattices. Recent improvements of the code include a unique approach of 3D-interaction between ions and target atoms. Application of the McChasy code in the analysis of crystal defects is described and possible ways of its further development are pointed out.