A study of defect evolution in multi-energy helium implanted monocrystalline and polycrystalline silicon

Upon implantation, He ions interact with radiation damage in metals and semiconductors to form bubbles (V. Raineri, Phys. Rev. B 2, 937 (2000) [1]). As far as Si is concerned, recent literature contains much information on the effects of ion implantation, defect formation and the transport of point defects in He-irradiated crystalline silicon (c-Si) whereas little information exists on the effects of He implantation on polycrys-talline Si (poly-Si). This paper reports on a systematic comparison of the effects of He implantation on c-Si and poly-Si. Interesting and significant differences were observed in the defect morphology in the two cases. Results on the differences between the two materials are presented and discussed in terms of the role that grain boundaries in poly-Si play in trapping interstitials and the effects that this may have on the overall defect morphology.