Impurities in MeV-implanted and annealed samples could be trapped at interstitial defects near to the projected ion range, and also at vacancy-related defects at about 50% of this range. An investigation was made, of the temperature dependence of impurity trapping at these secondary defects, by annealing at 900C. The binding energies of Fe, Ni and Cu were greater at vacancy-related defects than at extrinsic dislocation loops. During subsequent processing, at temperatures of up to 900C, the amount of impurity which was trapped at half of the projected range increased with decreasing temperature while the amount which was trapped at the full range decreased. Most of the trapped metals were located at half of the range in samples which were processed at temperatures below 700C. Intrinsic O was trapped at both types of defect. This appeared to have little effect upon the trapping of metallic impurities at extrinsic dislocations, but could inhibit or completely suppress trapping at vacancy-related defects.

Impurity gettering to secondary defects created by MeV ion implantation in silicon R.A.Brown, O.Kononchuk, G.A.Rozgonyi, S.Koveshnikov, A.P.Knights, P.J.Simpson, F.González: Journal of Applied Physics, 1998, 84[5], 2459-65