Creation of internal point defect drains in silicon by carbon implantation

High-dose carbon implantations into silicon at temperatures between 150 and 250 degreesC result in the formation of a buried amorphous layer with a layer of self-organized nanometric amorphous SiCx precipitates and a completely crystalline Si top layer above. It is shown by RBS channeling and cross-sectional TEM that the nature of defects in the top layer critically depends on the implantation temperature and determines the annealing behaviour of amorphous SiCx precipitates. For lower implantation temperatures, when extended defects are absent in the top layer, 900 degreesC annealing leads to partial crystallization of amorphous SiC, precipitates, accompanied by void formation. Crystallizing SiC, precipitates then act as sinks for silicon self-interstitials. For higher implantation temperatures, dislocations on {1 1 1} planes and {3 1 1}-defects effectively trap the self-interstitials and inhibit the crystallization of amorphous SiCx. It is also shown that the crystallization temperature of SiC in the continuous buried amorphous layer depends on the implantation temperature. (C) 2003 Elsevier Science B.V. All rights reserved.