Spectroscopic studies of H-decorated interstitials and vacancies in thin-film silicon exfoliation

In this paper, we review the pivotal role that defects tin particular vacan cy structures play in driving the H-2-induced exfoliation of Si. We highlig ht the central role that infrared spectroscopy has played in delineating th e microscopic details of the exfoliation process. We show that when the res ults of such spectroscopic studies are combined with those obtained using a variety of other experimental probes as well as ab initio quantum chemical cluster calculations, an unambiguous mechanistic picture emerges. Specific ally we find that H-2-terminated vacancy structures drive the formation of internal surfaces into cracks where Hz is then evolved, resulting in the bu ild-up of sufficient internal pressure to cause lift-off of the overlying S i. The role of coimplantation of He is also discussed. (C) 1999 Elsevier Sc ience B.V. All rights reserved.