Is there a future for semiconducting silicides? (invited)

Silicon is commercially by far the most important semiconductor, however, b ecause silicon has an indirect band gap it would initially appear to be uns uitable for optoelectronic applications. A major research challenge is, the refore, to achieve high intensity light emission from silicon and to engine er active and passive optical structures within it. This paper examines the potential of semiconducting silicides (principally, beta FeSi2 and Ru2Si3) for silicon-based optoelectronic applications. It traces the history of th e subject from the first photoluminescence spectrum from beta FeSi2 to a wo rking LED which uses beta FeSi2 precipitates as a route for fast radiative recombination. Recent results on semiconducting Ru2Si3 are also reported, w hich show, for the first time, that this material can be fabricated by high dose ion implantation. They also reveal a direct band gap of 0.91 eV, The future for semiconducting silicides is examined and, although there are sti ll barriers to overcome the future looks bright. (C) 2000 Elsevier Science B.V. All rights reserved.