Cavities in single crystalline silicon are shown to act as gettering centers for the vacancies produced during an ion implantation process: the effect of the gettering is observed as an increase of their total volume. Helium implantation at 20 keV with a dose of 2 x 10(16) cm(-2) plus a heat treatment at 850 degrees C for 3 hours produces the cavities; vacancies are supplied by a subsequent 0.8 x 10(16) cm(-2) helium implant. In this case the vacancy-gettering efficiency, i.e. average increase of vacancies involved in stable voids per helium ion, is found to be 0.53 vacancies ion(-1); about 4 times more compared to the case when the same 0.8 x 10(16) cm(-2) implant is performed on a virgin crystal. A further effect is the peculiar helium behavior which acts as a stabilizer of the vacancies produced during the implantation. The differential vacancy-gettering efficiency is found to increase with the helium dose: about 0.13 vacancies ion(-1) at 0.8 x 10(16) cm(-2), 0.4 vacancies ion(-1) at 2 x 10(16) cm(-2), and 3.8 vacancies ion(-1) at 2.8 x 10(16) cm(-2) .
Vacancy-gettering in silicon: Cavities and helium-implantation / Corni, Federico; Tonini, Rita; Frabboni, Stefano; Nobili, Carlo Emanuele; Calzolari, G; Masetti, S; Tamarozzi, P; Pavia, G; Cerofolini, Gf. - In: DIFFUSION AND DEFECT DATA, SOLID STATE DATA. PART B, SOLID STATE PHENOMENA. - ISSN 1012-0394. - STAMPA. - 70:(1999), pp. 229-233. [10.4028/www.scientific.net/SSP.69-70.229]