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Oxide Isolated Epitaxial Layers

IP.com Disclosure Number: IPCOM000048540D
Original Publication Date: 1982-Feb-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 72K

Publishing Venue

IBM

Related People

Thomas, DR: AUTHOR

Abstract

Isolated islands of a high quality epitaxial layer are provided on oxidized porous silicon by forming the epitaxial layer on porous silicon and then oxidizing the porous silicon.

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Oxide Isolated Epitaxial Layers

Isolated islands of a high quality epitaxial layer are provided on oxidized porous silicon by forming the epitaxial layer on porous silicon and then oxidizing the porous silicon.

As shown in Fig. 1, a porous layer of silicon 10 is formed on a silicon substrate 12 by anodic reaction of silicon to hydrogen flouride. A thin epitaxial layer 14 is then grown on the surface of the porous silicon layer 10. Trenches 16 are etched through the epitaxial layer 14 into the porous silicon layer 10. The porous silicon layer 10 under the epitaxial layer 14 is then oxidized to provide the desired isolation. If preferred, a layer of silicon nitride 18 may be formed on the epitaxial layer 14 before the trenches 16 are formed to prevent oxidization of the upper surface of epitaxial layer 14.

A method for forming the oxide isolated epitaxial layer, which differs somewhat from the method and structure indicated in Fig. 1, is shown in Fig. 2. In Fig. 2, regions 16' of the epitaxial layer 14 are selectively formed into porous silicon material to the underlying porous silicon layer 10 and then all porous silicon material is oxidized.

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