Methods to fabricate mosfet devices using selective deposition process

Abstract

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 ClSiH, 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 SiHand 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.