Extended defect formation and the flux of interstitials in Si-ion implanted silicon

Abstract

We have investigated the role of silicon interstitials, released during the annealing of self-ion implanted silicon, in the formation of extended defects. Levels of implant damage are varied by control of implant temperature and ion flux; however, it is shown that the formation of extended defects depends on the implant fluence, not on the net amount of primary damage. Ion implanted delta-doped boron structures are used to detect released Si interstitials. It is observed that below a fluence of 1 × 10 14 cm −2 the excess interstitials escape the implanted region during annealing and extended defects do not form. Above this fluence, most of the excess interstitials remain in the implanted region, agglomerating into extended defects while a small fraction escape, causing enhanced diffusion in boron delta-doped layers outside the implanted region. The data indicate that, for self-implantation, extended defect formation can be understood in terms of the plus-one model.