Gold Gettering by H~+ or He~(++) Ion Implantation Induced Cavities and Defects in Cz Silicon Wafers

摘要

In this paper, we investigate, in Cz wafers, the trapping of gold by defects and nanocavities formed by implantation of He~(++) or H~+ ions at 250 keV and at a dose of 3.10~(16)cm~(-2) followed by subsequent annealing(s) at 750℃ for 1 hour. Deep level transient spectroscopy profiles show that substitutional gold concentration decreases near the cavity band in Cz samples. Gold profiles obtained by secondary ion mass spectroscopy show that there is a strong trapping of gold in the cavity band in all samples. In the case of He~(++) implanted wafers, this trapping occurs also in the region between the implanted surface and the cavities. This could be explained by a higher density of implantation induced defects in He~(++) implanted samples and by the formation of oxygen-vacancy complexes in this region. The results suggest that gold trapping is related to gold precipitation which could inject self-interstitials in the bulk and then, decreases the substitutional gold concentration.