Browse Prior Art Database

Complex Insulator Layer Processing

IP.com Disclosure Number: IPCOM000080654D
Original Publication Date: 1974-Jan-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Chappelow, RE: AUTHOR [+3]

Abstract

It has been shown that when a layer of silicon nitride Si(3)N(4) is subjected to a high-temperature oxygen O(2) anneal cycle, a thin layer of oxygen bearing material, here referred to as oxynitride, is formed. The resulting structure significantly improves V(t) stability in the devices. This oxynitride layer has, however, been shown to be incompatible with a subsequent standard polycrystalline silicon deposition process.

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Complex Insulator Layer Processing

It has been shown that when a layer of silicon nitride Si(3)N(4) is subjected to a high-temperature oxygen O(2) anneal cycle, a thin layer of oxygen bearing material, here referred to as oxynitride, is formed. The resulting structure significantly improves V(t) stability in the devices. This oxynitride layer has, however, been shown to be incompatible with a subsequent standard polycrystalline silicon deposition process.

In particular, the incompatibility lies in the fact that hydrogen H(2) is used for the carrier gas in the standard process, in which case anomalous polycrystalline silicon growth takes place. Several polycrystalline silicon processes are known which do not utilize H(2) as a carrier gas, but these known processes have been shown experimentally to suffer from other, inherent, adverse effects.

In the present process the O(2) anneal of the Si(3)N(4) is carried out to improve V(t) stability. Polycrystalline silicon is then deposited in a two-step process. The process involves a standard SiH(4)-BBr(3) gas mixture. First, 500 Angstroms of polycrystalline silicon is deposited in a nitrogen N(2) carrier, and then the remaining several thousand Angstroms of polycrystalline silicon is deposited using a standard H(2) carrier gas. Since the anomalous growth does not occur in N(2), no interaction takes place between polycrystalline silicon and the silicon oxynitride layer during the first step. This cycle does, however, "cap ...