The effect of He and B co-implantation upon the point-defect population was investigated. Wafers were implanted with 12keV B ions to 5 x 1014/cm2 and/or with 25–80keV He ions to between 5 x 1015 and 3 x 1016/cm2. By means of B diffusion and Cu gettering experiments, the effectiveness of He induced nanovoids in controlling the self-interstitials generated by implantation was studied. It was demonstrated that nanovoids strongly affected B diffusion; producing a B box-like shape. Their efficiency increased with increasing He fluence. Moreover, this beneficial effect was still present, increasing the annealing temperature from 700 to 1000C and leading to a reduction in B clustering while maintaining strong confinement of the implanted B profile.

He Implantation in Si for B Diffusion Control. E.Bruno, S.Mirabella, E.Napolitani, F.Giannazzo, V.Raineri, F.Priolo: Nuclear Instruments and Methods in Physics Research B, 2007, 257[1-2], 181-5