In one embodiment, a method for fabricating a
silicon-based device on a
substrate surface is provided which includes depositing a first
silicon-containing layer by exposing the
substrate surface to a first process gas comprising Cl2SiH2, a
germanium source, a first etchant and a carrier gas and depositing a second
silicon-containing layer by exposing the first silicon-containing layer to a second process gas comprising SiH4 and a second etchant. In another embodiment, a method for depositing a silicon-containing material on a
substrate surface is provided which includes depositing a first silicon-containing layer on the substrate surface with a first
germanium concentration of about 15 at % or more. The method further provides depositing on the first silicon-containing layer a second silicon-containing layer wherein a second
germanium concentration of about 15 at % or less, exposing the substrate surface to air to form a native
oxide layer, removing the native
oxide layer to
expose the second silicon-containing layer, and depositing a third silicon-containing layer on the second silicon-containing layer. In another embodiment, a method for depositing a silicon-containing material on a substrate surface is provided which includes depositing epitaxially a first silicon-containing layer on the substrate surface with a first
lattice strain, and depositing epitaxially on the first silicon-containing layer a second silicon-containing layer with a second
lattice strain greater than the first
lattice strain.