A review was presented of the results of experiments concerning the elucidation of the thermal evolution of the self-interstitial excess which was introduced by Si-ion implantation into crystalline material. Deep-level transient spectroscopy and photoluminescence measurements were used to monitor interstitials which were stored in stable point-like defect structures just after implantation, evolved into defect clusters upon annealing at intermediate temperatures, and then annealed out and released the stored self-interstitials upon annealing at higher temperatures. It was shown that, although dopant atoms and impurities (C, O) were not the main constituents of these clusters, the impurity content had a large effect in the early stages of cluster formation at low fluences and low temperatures and could affect their dissociation kinetics. A stable residual damage, which was electrically characterized by signatures at Ev + 0.33eV and Ev + 0.52eV (and exhibited 2 broad signatures in the photoluminescence spectrum), was detected for doses above 1012/cm2 and annealing temperatures above 600C. This residual damage, which was made up of interstitial clusters, was stable up to temperatures as high as 750C. It annealed out with an activation energy of about 2.3eV. It was suggested that these clusters stored the interstitials which drove transient enhanced diffusion at low implantation doses and/or low temperatures; when no extended defects were formed. When {311} extended defects formed, the luminescence spectrum was dominated by a sharp signal at 1376nm. This was related to optical transitions which occurred at, or close to, these defects. Dose and temperature thresholds were observed for the transition from small clusters to extended defects.

Formation, Evolution and Annihilation of Interstitial Clusters in Ion-Implanted Si. S.Libertino, S.Coffa, J.L.Benton: Physical Review B, 2001, 63[19], 195206