Browse Prior Art Database

Self Aligning Oxidization Barrier

IP.com Disclosure Number: IPCOM000051916D
Original Publication Date: 1981-Apr-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Dun, H: AUTHOR [+2]

Abstract

This method provides a sequence of steps including a lift-off technique to produce a silicon nitride barrier self-aligned to a polysilicon gate, subsequently permitting independent polysilicon oxidization thickness variations or control.

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Self Aligning Oxidization Barrier

This method provides a sequence of steps including a lift-off technique to produce a silicon nitride barrier self-aligned to a polysilicon gate, subsequently permitting independent polysilicon oxidization thickness variations or control.

The steps of this method more specifically include:

1. Depositing a layer of polysilicon on, e.g., a semiconductor substrate or on an oxide previously formed on the substrate.

2. Defining a given segment of the polysilicon layer with a photoresist mask and etch so as to undercut the polysilicon layer under the photoresist, as indicated in Fig. 1.

3. Depositing a non-conformal film of silicon nitride at a low temperature over the photoresist and over the surface of the substrate or oxide without coating the edges under the photoresist, as indicated in Fig. 2.

4. Lifting off the photoresist and that portion of the silicon nitride film formed over the photoresist, as indicated in Fig. 3.

5. Oxidizing the polysilicon segment to form a polysilicon oxide to the desired thickness, as indicated in Fig. 4.

6. Removing the remaining portions of the silicon nitride film by any known technique.

The silicon nitride film may be a silicon-rich nitride, deposited by using plasma chemical vapor deposition techniques, as the oxidation-resistant barrier.

It can be seen that a method has been provided wherein area surrounding a segment of a polysilicon layer can be selectively protected from oxidizing atmospheres, w...