A preliminary study was made of B diffusion in the presence of pre-formed voids having various characteristics. The voids were fabricated by He implantation, followed by annealing; allowing the desorption of He prior to B implantation. It was shown that, under such conditions, B diffusion was always largely reduced and could even be suppressed in some cases. Boron diffusion suppression could be observed in samples which did not contain nanovoids in the B-rich region. It was suggested that direct trapping of Sii by the voids was not the mechanism responsible for the reduction of B diffusion in such layers. Alternatively, the experimental results suggested that this reduction in diffusivity was more probably due to competition between 2 Ostwald ripening phenomena taking place at the same time: in the B-rich region, the competitive growth of extrinsic defects at the origin of TED and, in the void region, the Ostwald ripening of the voids which involved high supersaturations of Vs.

Effect of Voids-Controlled Vacancy Supersaturations on B Diffusion. O.Marcelot, A.Claverie, F.Cristiano, F.Cayrel, D.Alquier, W.Lerch, S.Paul, L.Rubin, H.Jaouen, C.Armand: Nuclear Instruments and Methods in Physics Research B, 2007, 257[1-2], 249-52