Patent ID: 7176101
Filing Date: 2007-02-13
Classification: H01L

Abstract:
1. A method of forming an isolation oxide layer, the method comprising: forming a first oxide layer on a silicon substrate; selectively etching the first oxide layer until the silicon substrate is partly exposed, thereby forming a plurality of openings in the first oxide layer, wherein each opening defines a first active region; forming a first silicon epitaxial layer on the silicon substrate in the openings, wherein the first silicon epitaxial layer forms a plurality of first active regions; forming a second oxide layer on both the first oxide layer and the first silicon epitaxial layer; etching the second oxide layer and the first oxide layer such that the first oxide layer is wholly removed and the second oxide layer remains only on the first silicon epitaxial layer; thermally growing a third oxide layer on entire resultant surfaces; blanket-etching the third oxide layer such that the third oxide layer remains only on sidewalls of the first silicon epitaxial layer, wherein the silicon substrate is exposed between the adjacent first active regions formed by the first silicon epitaxial layer; forming a second silicon epitaxial layer on the exposed silicon substrate, wherein the second silicon epitaxial layer forms a plurality of second active regions between the first active regions; and removing the second oxide layer remaining on the first silicon epitaxial layer, wherein the first and second active regions are disposed one by one, being physically separated and electrically isolated by the third oxide layer.