Self-Interstitial Migration in Si Implanted with Oxygen

High dose oxygen implantation in silicon creates various defects mainly SiO 2 precipitates, small dislocation loops and elongated Frank dipoles located in the {1 1 1} planes. At implantation temperatures in the range 600-700°C the distribution of the SiO 2 precipitates is periodic with a period about 4 nm. The Frank dipoles are located near the Si overlayer/SiO 2 buried layer interface while the small dislocation loops are situated near the surface. The observation, through high resolution electron microscopy, that the SiO 2 precipitates are free of strain implies the existence of a very effective mechanism for Si self-interstitial migration, while the periodic structure of the precipitates is related to the formation of channels to incorporate easy paths of uniform self interstitial migration. The formation of the small dislocation loops near the surface is also attributed to the high flux of self interstitials.