Patent ID: 6579807
Filing Date: 2003-06-17
Classification: H01L

Abstract:
A method for forming an isolation layer in a semiconductor substrate, comprising:preparing the semiconductor substrate comprising a silicon crystal layer and an insulating layer, wherein the silicon crystal layer is formed on the insulating later; forming a silicon oxide layer on the silicon crystal layer; forming a first silicon nitride layer on the silicon oxide layer; partially removing the silicon oxide layer and the first silicon nitride layer so as to expose a portion of the silicon crystal layer; depositing a second silicon nitride layer above the silicon crystal layer by a chemical vapor deposition process, wherein the first silicon nitride layer and the exposed portion of the silicon crystal layer are substantially covered by the second silicon nitride layer; removing the second silicon nitride layer so as to leave parts of the second silicon nitride layer at side surfaces of the first silicon nitride layer located over the exposed portion of the silicon crystal layer; cleaning the exposed portion of the silicon crystal layer; forming the isolation layer in the exposed portion of the silicon crystal layer by a heat treatment.