Buried amorphous layers have been produced in silicon single crystal by lithium implantation at liquid nitrogen temperature and followed by a 400 degrees C annealing. By this process, a wide region, perfectly crystalline and free of any extended defect, is formed ahead of the buried amorphous layer up to the implanted surface. Neon has then been implanted in this front region at high fluence and high temperature (250 degrees C) in order to create bubbles and avoid further amorphization. In the presence of a buried amorphous layer, significant decrease of the extended defect density is observed at the neon end of range region. The results are discussed in terms of interstitial trapping, i.e. the buried amorphous layer acting as an efficient sink for interstitials during recrystallization. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim