Effect of damage production rate in aluminium surface treatment using an ECR–PBII apparatus

The damage production rate is an important factor in the diffusion of different species during implantation, for instance O-ion PBII of Al and its alloys. In this experiment, we try to distinguish the effect of purely radiation-enhanced diffusion (RED) from the synergistic effect between RED and Mg segregation driven by oxidation observed in earlier work with Mg-containing Al alloys. We investigated the influence of the irradiation damage on pure Al for which no segregation effect can occur. We used different gas compositions [O2, Ar, Ar(10%O2) and Ne(10%O2)] to provide simultaneous species implantation and a variable ratio of damage to active ion implantation rate. The effect of the damage rate on the O implanted profiles was measured by XPS. Following implantation with an Ar(10%O2) plasma, a very significant inward displacement of the peak concentration was observed. Analysis of the profiles leads to the conclusion that a purely RED effect is involved in this O migration.