Vacancy Cluster Distributions in He Implanted Silicon Studied by Slow Positron Annihilation Spectroscopy |
| R.S. Brusa Istituto Nazionale per la Fisica della Materia, Dipartimento di Fisica, Universita' di Trento 38050 Povo TN, Italy |
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| Doppler broadening measurements performed by a slow positron beam on p-type Si samples implanted with He at 20 keV and at a fluence of 5×1015 and 2×1016 cm-2 are reviewed and discussed. The evolution of the open volume defects distribution was studied as a function of isochronal and isothermal annealing of the samples. In the as implanted samples the majority of the open volume defects produced by implantation was passivated by He. The open volume defects density decreases, reaching a minimum at 250°C. In the 250-650°C temperature range there is an increase in defects due to the appearance of vacancy clusters. At the higher annealing temperatures (700-900°C) the vacancy clusters disappear only in the samples implanted at 5×1015 cm-2. |
| DOI: 10.12693/APhysPolA.95.474 PACS numbers: 71.60.+z, 78.70.Bj, 71.55.Cn |