US4868632A
Expired / Lapsed
US
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Nonvolatile semiconductor memory
Assignee: DIRECTOR GENERAL OF AGENCY OF INDUSTRIAL SCIENCE AND TECHNOLOGY3-1
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Filing: 1988-07-08
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Granted: 1989-09-19
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Expires: 2008-07-08
Abstract
Abstract In an MONOS type nonvolatile semiconductor memory comprising a channel forming semiconductor region between source and drain regions in a surface of a substrate; a tunnel insulating film formed on the channel forming semiconductor region in the surface of the substrate, the tunnel insulating film permitting charge-injection; a silicon nitride film formed as a second insulating film on the tunnel insulating film; a silicon oxide film formed as a third insulating film; and a conductive electrode formed on the silicon oxide film, the silicon nitride film has a composition close to a stoichiometric value of Si 3 N 4 at a portion near an interface with the tunnel insulating film and has a composition of excess silicon at a portion of the thickness of the same film except near the interface with the tunnel insulating film.
Inventors
- 👤 Yutaka Hayashi
- 👤 Itsunari Hayabuchi
- 👤 Tatsuo Tsuchiya
- 👤 Seiichi Ishihara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:01
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/67; H10D30/6704; H10D30/6727; H10D30/69
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
156 words
A MONOS type nonvolatile semiconductor memory comprising: a channel forming semiconductor region between source and drain regions in a surface of a substrate; a tunnel insulating film formed as a first insulating layer on said channel forming semiconductor region in the substrate, said tunnel insulating film permitting charge-injection; a silicon nitride film formed as a second insulating layer on said tunnel insulating layer; a silicon oxide film formed as a third insulating layer on said silicon nitride film; and a conductive electrode formed on said silicon oxide film; said silicon nitride film having a composition close to a stoichiometric value of Si 3 N 4 at a portion near an interface with said tunnel insulating film and at a portion near an interface with said silicon oxide film, and having a composition of excess silicon more than the stoichiometric value of Si 3 N 4 at a portion near the middle of the silicon nitride film.
Claim 2
Dependent Claim
156 words
A MONOS type nonvolatile semiconductor memory comprising: a channel forming semiconductor region between source and drain regions in a surface of a substrate; a tunnel insulating film formed as a first insulating layer on said channel forming semiconductor region in the substrate, said tunnel insulating film permitting charge-injection; a silicon nitride film formed as a second insulating layer on said tunnel insulating layer; a silicon oxide film formed as a third insulating layer on said silicon nitride film; and a conductive electrode formed on said silicon oxide film; said silicon nitride film having a composition close to a stoichiometric value of Si 3 N 4 at a portion near an interface with said tunnel insulating film and at a portion near an interface with said silicon oxide film, and having a composition of excess silicon more than the stoichiometric value of Si 3 N 4 at a portion near the middle of the silicon nitride film.
Claim 3
Dependent Claim
144 words
A MONOS type nonvolatile semiconductor memory comprising: a channel forming semiconductor region between source and drain regions in a surface of a substrate; a tunnel insulating film formed as a first insulating layer on said channel forming semiconductor region in the substrate, said tunnel insulating film permitting charge-injection; a silicon nitride film formed as a second insulating layer on said tunnel insulating film; a silicon oxide film formed as a third insulating layer on said silicon nitride film; and a conductive electrode formed on said silicon oxide film; said silicon nitride film having a composition close to a stoichiometric value of Si 3 N 4 at a portion near an interface with said tunnel insulating film, and having a composition of excess silicon more than the stoichiometric value of Si 3 N 4 at a portion near an interface with said silicon oxide film.
Claim 4
Dependent Claim
144 words
A MONOS type nonvolatile semiconductor memory comprising: a channel forming semiconductor region between source and drain regions in a surface of a substrate; a tunnel insulating film formed as a first insulating layer on said channel forming semiconductor region in the substrate, said tunnel insulating film permitting charge-injection; a silicon nitride film formed as a second insulating layer on said tunnel insulating film; a silicon oxide film formed as a third insulating layer on said silicon nitride film; and a conductive electrode formed on said silicon oxide film; said silicon nitride film having a composition close to a stoichiometric value of Si 3 N 4 at a portion near an interface with said tunnel insulating film, and having a composition of excess silicon more than the stoichiometric value of Si 3 N 4 at a portion near an interface with said silicon oxide film.
Claim 5
Dependent Claim
57 words
A MONOS type nonvolatile semiconductor memory according to claim 1 or 2, wherein the concentration of silicon of a region between the portion having a composition close to the stoichiometric value of Si 3 N 4 and the portion having the composition of excess silicon more than the stoichiometric value of Si 3 N 4 varies gradually.
Claim 6
Dependent Claim
60 words
A MONOS type nonvolatile semiconductor memory according to claim 1 or 2 wherein the concentration of silicon of a region between the portion having the composition close to the stoichiometric value of Si 3 N 4 and the portion having the composition of excess silicon more than the stoichiometric value of Si 3 N 4 varies in a stepwise way.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-09-18 | 1993-03-20 | 1993-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-18 | 1997-03-20 | 1997-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-18 | 2001-03-20 | 2001-09-19 | $7700.00 | Window Closed / Lapsed |