Patent ID: 7737007

Claim:
A method for forming a silicon-based material on a substrate surface, comprising: exposing a substrate to a first process gas comprising silane, a germanium source, a carbon source, a first etchant comprising HCl, and a carrier gas to selectively and epitaxially deposit a first silicon-containing layer on the substrate at a pressure within a range from about 0.5 Torr to about 50 Torr, wherein the first silicon-containing layer comprises a graded carbon concentration and has interstitial sites within a crystalline lattice and comprises about 3 at % or less of carbon within the interstitial sites; exposing the substrate to a second process gas comprising dichlorosilane and a second etchant comprising HCl to selectively and epitaxially deposit a second silicon-containing layer on the first silicon-containing layer; and annealing the substrate to incorporate at least a portion of the carbon into substitutional sites of the crystalline lattice within the first silicon-containing layer.