Patent ID: 7232728

Claim:
A method for forming an oxide layer on a silicon wafer, the method comprising: forming a pad oxide layer on the silicon wafer; forming a nitride island on the pad oxide layer to mask an active area of the silicon wafer; forming field oxide regions in non-active areas; stripping the nitride island; stripping the pad oxide layer in an oxygen-free environment, wherein the pad oxide layer being stripped in the oxygen-free environment is the pad oxide layer formed beneath the nitride island before the nitride island was stripped; maintaining the wafer in a controlled environment; exposing the active area while the controlled environment is in a first state, wherein the first state comprises an environmental state selected from the group consisting of the oxygen-free environment and a low-pressure, virtually oxygen-free environment, wherein the controlled environment is maintained continuously between stripping the pad oxide layer and exposing the active area; selectively growing an epitaxial silicon layer only on the surface of the active area while depositing substantially no silicon on the field oxide regions, and while the controlled environment is in the first state so as to cover defects in the silicon wafer present in the active area; thermally oxidizing at least a portion of the epitaxial silicon layer while the controlled environment is in a second state, thereby forming a non-sacrificial oxide layer, wherein the second state is an oxidizing environment; and maintaining the controlled environment in the first state continuously between selectively growing the epitaxial silicon layer and forming the non-sacrificial oxide layer.