STUDY OF THE DYNAMIC PROCESSES INVOLVED DURING NITROGEN IMPLANTATION INTO ALUMINUM

Nitrogen implantation into aluminum has been widely investigated in the past few years because of its potential industrial applications. It has already been observed that the shape and the thickness of the formed layer strongly depend on the implantation doses for a given energy: at room temperature, when the incident dose is larger than 5 x 10(17) N+ cm-2, nitrogen distribution broadens and later becomes trapezoidal. The aim of this work was to investigate the atomic movements of nitrogen during implantation which leads to the formation of the wide aluminum nitride layer. In order to understand these mechanisms, an aluminum sample was pre-implanted with 3 x 10(17) N-15 cm-2 and post-bombarded at different doses of N-14. We used the selectivity of the resonant nuclear reaction to measure the redistribution of the N-15 nitrogen. The results indicate that nitrogen atoms present in the matrix are displaced by the incoming ions. The depth distribution of N-15 is split into two components. The most important component is found in the bulk and can be explained by ion beam mixing. A theoretical model of such a double implantation based on the idea that ion beam mixing can be treated like a diffusion process, allows us to reproduce the experimental results.