Impurity-assisted annealing of point defect complexes in ion-implanted silicon

Annealing of vacancy-related defect complexes in CZ and FZ n-type silicon crystals has been studied by means of deep level transient spectroscopy. Characteristic vacancy-related defects such as VO and V-2 were introduced by electron irradiation or implantation with C+, Si+, Ge+, and I+ ions using very low doses. It was found that the overall thermal stability of both V-2 and VO is almost independent on the mass of the primary projectile. However, after initial annealing stages (T less than or equal to 200 degrees C) a significant increase of the normalized V-2 and VO signals was detected for heavy ions (Ge+, I+). Moreover, depth profiling of the CZ samples implanted with Si+ ions reveals a substantial narrowing of the V-2 and VO distributions after initial annealing stages. Both phenomena may be interpreted in terms of a preferential formation and subsequent dissociation of high-order vacancy clusters at the depth corresponding to the peak of the implantation damage. (C) 1999 Elsevier Science B.V. All rights reserved.