Metastable Sic and SiGeC Alloys by Carbon Implantation and Solid Phase Epitaxy

Abstract

ABSTRACTWe demonstrate the formation of metastable Si1-yCy and Si1-y-xGexCy alloys by C ion implantation and solid phase epitaxial regrowth. Carbon was introduced into Si and SiGe layers by 5, 12 and 25 keV implants to achieve nearly uniform profiles of 0.7 and 1.4 at.% C. The 0.7 at.% C specimens exhibit the highest quality epitaxial layers after SPE regrowth, whereas in higher C concentration specimens solid phase regrowth was impeded. The localized vibrational mode of C occupying substitutional lattice sites in the diamond lattice provides a signature of the metastable phase and is used to monitor the loss of stability due to precipitation of silicon carbide. The Sic and SiGeC alloys retained substitutional carbon during 30 minute isochronal anneals up to 850°C.