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Formation of Thick Si(3)N(4) or Si(x)O(y)N(z) on SI Substrate by Anodnitridization

IP.com Disclosure Number: IPCOM000086256D
Original Publication Date: 1976-Aug-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Poponiak, MR: AUTHOR [+2]

Abstract

Direct conversion of the silicon substrate into silicon nitride (Si(3)N(4)) or silicone oxymitride (Si(x)O(y)N(z)) films can be made to conform the topology of a silicon, Si, substrate or to recess into the Si substrate, so as to make the Si substrate surface isoplanar. The material can also be made into an envelope in the Si substrate to completely isolate, dielectrically, a portion of the Si substrate from the rest of the substrate.

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Formation of Thick Si(3)N(4) or Si(x)O(y)N(z) on SI Substrate by Anodnitridization

Direct conversion of the silicon substrate into silicon nitride (Si(3)N(4)) or silicone oxymitride (Si(x)O(y)N(z)) films can be made to conform the topology of a silicon, Si, substrate or to recess into the Si substrate, so as to make the Si substrate surface isoplanar. The material can also be made into an envelope in the Si substrate to completely isolate, dielectrically, a portion of the Si substrate from the rest of the substrate.

To form the Si(3)N(4) or Si(x)O(y)N(z) film, the Si substrate is first anodized in a hydrofluoric acid, HF, containing solution to form a porous silicon layer. This roughly defines the Si(3)N(4) or Si(x)O(y)N(z) film that would be formed by a subsequent nitridization (or oxynitridization) step. To form the relatively dense film, the anodized Si substrate is then heat treated in a furnace in a temperature range of 800 degrees C-1300 degrees C using a gas flow of pure ammonia, NH(3), or of NH(3) and oxygen, O(2), mixture depending upon whether pure Si(3)N(4) or Si(x)O(y)N(z) is to be formed. The oxygen content of the Si(x)O(y)N(z) film may be varied by varying the O(2) content in the gas flow.

To facilitate the nitridization process, an inert gas, such as nitrogen, N(2), may be added to the gas flow. In the formation of oxynitride film, other oxygen containing gases, such as carbon dioxide, CO(2), and nitric oxide, NO(2), may also be used in the place o...