Voids in silicon substrates for novel applications

The mechanisms of He-bubble and, after annealing, of void formation is desc ribed. Size effects of protrusions of the implanted region indicate a He di ffusion mechanism and an interaction with vacancies and divacancies for the bubble formation. PL has revealed helium inside divacancies in the same ra nge of temperatures where self-interstitials, produced during implantation, have been observed to recombine at the sample surface. As a consequence th e inversion in the vacancy-interstitial balance is produced and a supersatu ration of vacancies is observed. The main properties of voids when used to getter metal impurities or to control locally lifetime are also described a nd discussed. (C) 2000 Elsevier Science S.A. All rights reserved.