Point defect trapping in ion implanted Al(Cu)

Abstract

The apparent substitutional fraction ƒ s as determined by MeV He ion channeling for Al single crystals implanted with Cu ions at 5 K and 77 K with peak concentrations between 0.14 and 1.22 at.% is 0.94 ± 0.03 in the 〈100〉 and 0.82 ± 0.03 in the 〈110〉 crystal directions. These values decrease after annealing to 293 K due to vacancy trapping. The dechanneling yield of the Al host lattice increases due to vacancy clustering. Further annealing to T ⋍ 450 K causes a complete disappearance of the radiation damage and ƒ s recovers to the as implanted values. Irradiation of the annealed samples with He ions at 77 K leads to a decrease of ƒ s due to selfinterstitial atom (SIA) trapping, while the dechanneling yield increases due to SIA clustering. These changes recover during annealing to 293 K due to the annihilation of both Cu-SIA-complexes and the SIA clusters by mobile vacancies.