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Process For The Reduction Of Oxide Flaws In Double Polysilicon Metallurgy

IP.com Disclosure Number: IPCOM000048779D
Original Publication Date: 1982-Mar-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Barile, CA: AUTHOR [+4]

Abstract

In this process the use of an oxidation step at 1,000 degrees C in an oxygen/HCl environment is used to grow a smooth, stress-free sidewall oxide.

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Process For The Reduction Of Oxide Flaws In Double Polysilicon Metallurgy

In this process the use of an oxidation step at 1,000 degrees C in an oxygen/HCl environment is used to grow a smooth, stress-free sidewall oxide.

It has been discovered that during fabrication of double polysilicon metallurgy structures, stress-induced flaws, i.e., oxide cracks and polysilicon deformation, are formed. These flaws weaken the dielectric integrity between the polysilicon layers.

In this process these flaws are reduced significantly by oxidizing the second polysilicon layer at 1000 Degrees C in an O(2)/HCl ambient. Much smoother conformal sidewall oxides and less deformation in the lower polysilicon layer are a result of the stress-relieved nature of this high temperature oxidation. An increase in the first polysilicon layer doping assures that the oxide thickness ratio of the sidewall to the overlying polysilicon layer is greater than 1. The phosphorous concentration should be in the mid 10/20/ atoms/cm/3/. An oxygen preheat is required to prevent harmful autodoping effects.

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