The Rutherford back-scattering spectroscopic channelling spectra of deep ion implants were analyzed in order to deduce the depth profiles of displaced atoms. It was assumed that defects in as-implanted samples could be described as being atoms which were randomly displaced from lattice sites. In one method, which was based upon the 2-beam model, the de-channelling that was caused by defects was calculated by using a linear or a semi-empirical formula. In another method, the analyzing beam was divided into a greater number of components in order to follow the transverse energy distribution of the ions. Finally, a 3-dimensional Monte Carlo code which involved a detailed description of each ion path was used to identify the limits of the other approaches. It was shown that, when large amounts of damage were considered, all of the methods predicted essentially the same profiles. On the other hand, they disagreed considerably in other cases. The Monte Carlo calculations indicated that, in order to obtain reliable results, it was necessary to ensure a correct description of channelling energy losses during ion penetration into a disordered crystal.

E.Albertazzi, M.Bianconi, G.Lulli, R.Nipoti, M.Cantiano: Nuclear Instruments and Methods in Physics Research B, 1996, 118[1-4], 128-32