US4683640A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making a floating gate memory cell
Assignee: RCA Corp
•
Filing: 1986-04-15
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Granted: 1987-08-04
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Expires: 2006-04-15
Abstract
Abstract A method of making a floating gate memory cell wherein the capacitance between the control gate and floating gate can be independently controlled. Independent capacitance control is achieved by forming the inter-level dielectric in a step which is independent of the gate oxide growth process.
Inventors
- 👤 Lorenzo Faraone
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 05:45
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/031; H10D64/035
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
93 words
A method of making a floating gate storage device comprising the steps of: (a) forming a first insulating layer on a semiconductor substrate; (b) forming a first electroconductive layer on a portion of said first insulating layer; (c) forming a second insulating layer on said first electroconductive layer; (d) forming a mask on said second insulating layer; (e) forming a gate oxide on areas not subtended by said mask; (f) removing said mask; and (g) forming a second electroconductive layer on said second insulating layer and on a portion of said gate oxide.
Claim 2
Independent Claim
93 words
A method of making a floating gate storage device comprising the steps of: (a) forming a first insulating layer on a semiconductor substrate; (b) forming a first electroconductive layer on a portion of said first insulating layer; (c) forming a second insulating layer on said first electroconductive layer; (d) forming a mask on said second insulating layer; (e) forming a gate oxide on areas not subtended by said mask; (f) removing said mask; and (g) forming a second electroconductive layer on said second insulating layer and on a portion of said gate oxide.
Claim 3
Dependent Claim
40 words
A method of making a floating gate storage device in accordance with claim 1 further comprising the step of introducing impurities into said semiconductor substrate with said second electroconductive layer functioning as a mask to form source and drain regions.
Claim 4
Dependent Claim
27 words
A method of making a floating gate storage device in accordance with claim 2 further comprising the step of forming contacts on said source and drain regions.
Claim 5
Dependent Claim
25 words
A method of making a floating gate storage device in accordance with claim 2 wherein said impurities are introduced into said substrate by ion implantation.
Claim 6
Dependent Claim
28 words
A method of making a floating gate storage device in accordance with claim 2 wherein said semiconductor substrate is p-type single crystal silicon and said impurities are n-type.
Claim 7
Dependent Claim
28 words
A method of making a floating gate storage device in accordance with claim 2 wherein said semiconductor substrate is n-type single crystal silicon and said impurities are p-type.
Claim 8
Dependent Claim
27 words
A method of making a floating gate storage device in accordance with claim 1 wherein said first insulating layer is formed by thermally oxidizing said semiconductor substrate.
Claim 9
Dependent Claim
25 words
A method of making a floating gate storage device in accordance with claim 1 wherein said first and second electroconductive layers are n-doped polycrystalline silicon.
Claim 10
Dependent Claim
35 words
A method of making a floating gate storage device in accordance with claim 1 wherein said second insulating layer is a material selected from the group consisting of silicon dioxide, silicon nitride and silicon oxynitride.
Claim 11
Dependent Claim
28 words
A method of making a floating gate storage device in accordance with claim 9 wherein said silicon dioxide layer is formed by thermally oxidizing said first electroconductive layer.
Claim 12
Dependent Claim
29 words
A method of making a floating gate storage device in accordance with claim 1 wherein said first insulating layer is formed on the active-area regions of said semiconductor substrate.
Claim 13
Dependent Claim
32 words
A method of making a floating gate storage device in accordance with claim 1 wherein said mask is oxidation resistant and said gate oxide is formed by thermally oxidizing said semiconductor substrate.
References Cited (Backward Citations)
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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) | 1990-08-03 | 1991-02-02 | 1991-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-03 | 1995-02-02 | 1995-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-03 | 1999-02-02 | 1999-08-04 | $7700.00 | Window Closed / Lapsed |