Patent US4587709A successfully refreshed from Google Patents.
US4587709A
Expired / Lapsed
US
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Method of making short channel IGFET
Assignee: International Business Machines Corp
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Filing: 1983-06-06
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Granted: 1986-05-13
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Expires: 2003-06-06
Abstract
Abstract A process for defining small dimensions by forming a vertical step in an etchable material; edge depositing a masking material by angularly evaporating a metal; and etching away all of the first material not covered by the masking material; and device obtained by depositing source, drain, and gate defining material.
Inventors
- 👤 Alan B. Fowler
- 👤 Allan M. Hartstein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:09
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/025; H10D64/027; H10D30/00; H10D30/01; H10D30/021; H10D30/027; H10D30/0275; H10P; H10P76/00; H10P76/40; Y; Y10; Y10S; Y10S148/00; Y10S148/082
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
102 words
A process for fabricating a self-aligned gate field effect transistor which comprises: a. providing a vertical step in an isolation material on a semiconductor substrate; b. edge depositing metal against said vertical step by evaporating the metal at an angle sufficient to provide a thicker metal deposit adjacent to said step than over said surface. c. etching away said isolation material to the substrate, except where masked by said metal, thereby producing an isolation material mesa; and d. depositing source, drain, and gate defining material on the horizontal surfaces at both sides of said mesa and at the top of said mesa.
Claim 2
Dependent Claim
102 words
A process for fabricating a self-aligned gate field effect transistor which comprises: a. providing a vertical step in an isolation material on a semiconductor substrate; b. edge depositing metal against said vertical step by evaporating the metal at an angle sufficient to provide a thicker metal deposit adjacent to said step than over said surface. c. etching away said isolation material to the substrate, except where masked by said metal, thereby producing an isolation material mesa; and d. depositing source, drain, and gate defining material on the horizontal surfaces at both sides of said mesa and at the top of said mesa.
Claim 3
Dependent Claim
12 words
The process of claim 1 wherein said isolation material is an oxide.
Claim 4
Dependent Claim
12 words
The process of claim 1 wherein said metal is aluminum or gold.
Claim 5
Dependent Claim
10 words
The process of claim 1 wherein said metal is aluminum.
Claim 6
Dependent Claim
11 words
The process of claim 1 wherein said angle is about 80°.
Claim 7
Dependent Claim
27 words
The process of claim 1 wherein the ratio of thickness of the metal adjacent to said step to that on said surface is at least about 2:1.
Claim 8
Dependent Claim
23 words
The process of claim 1 wherein the thickness of the metal adjacent the step is about equal to the height of the step.
Claim 9
Dependent Claim
16 words
The process of claim 1 wherein the maximum width of the mesa is about 5000 angstroms.
Claim 10
Dependent Claim
17 words
The process of claim 1 wherein the width of said mesa is at least about 100 angstroms.
Claim 11
Dependent Claim
18 words
The process of claim 1 wherein the width of said mesa is about 150 to about 1000 angstroms.
Claim 12
Dependent Claim
24 words
The process of claim 1 which further includes providing doped silicon at the sides of said mesa and on the top of said mesa.
Claim 13
Dependent Claim
16 words
The process of claim 1 wherein the source and drain are provided by depositing doped silicon.
Claim 14
Dependent Claim
20 words
The process of claim 1 wherein said mesa is removed and the silicon on the top thereof is lifted off.
Claim 15
Dependent Claim
18 words
The process of claim 11 wherein metallic type interconnections are provided to the source, drain, and gate regions.
Claim 16
Dependent Claim
18 words
The process of claim 13 which further includes oxidizing the exposed silicon surfaces to provide a gate oxide.
Claim 17
Dependent Claim
17 words
The process of claim 15 wherein the gate oxide is about 50 to about 100 angstroms thick.
Claim 18
Dependent Claim
21 words
The process of claim 16 which further includes providing metallic type high electrical conductivity interconnection to said source and drain regions.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-05-12 | 1989-11-11 | 1990-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-12 | 1993-11-11 | 1994-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-12 | 1997-11-11 | 1998-05-13 | $7700.00 | Window Closed / Lapsed |