US4057788A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor memory structures
Assignee: Raytheon Co
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Filing: 1975-10-06
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Granted: 1977-11-08
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Expires: 1995-10-06
Abstract
Abstract A method of storing electric charges in a metal-nitride-oxide-semiconductor memory element by setting the threshold voltage of the element at any of a substantial number of voltages by applying both a DC voltage corresponding to the analog voltage to be stored and an AC voltage which is gradually reduced.
Inventors
- 👤 Jay P. Sage
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:06
CPC Classifications
G; G11; G11C; G11C27/00; G11C27/005; G11C16/00; G11C16/02; G11C16/04; G11C16/0466
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
113 words
In combination: a semiconductor memory device comprising a semiconductor substrate, an insulating layer provided on said semiconductor substrate, an electric charge capture layer provided on said insulating layer, and an electrode layer provided on said electric charge capture layer; and means for setting any of a plurality of predetermined voltages to said electrode layer relative to said semiconductor substrate to inject an electric charge into said electric charge capture layer from said semiconductor substrate, having a unidirectional component corresponding to said threshold voltage to be set and a cyclically varying component at least the amplitude or pulse length of which is gradually diminished during a plurality of cycles of said cyclically varying component.
Claim 2
Dependent Claim
113 words
In combination: a semiconductor memory device comprising a semiconductor substrate, an insulating layer provided on said semiconductor substrate, an electric charge capture layer provided on said insulating layer, and an electrode layer provided on said electric charge capture layer; and means for setting any of a plurality of predetermined voltages to said electrode layer relative to said semiconductor substrate to inject an electric charge into said electric charge capture layer from said semiconductor substrate, having a unidirectional component corresponding to said threshold voltage to be set and a cyclically varying component at least the amplitude or pulse length of which is gradually diminished during a plurality of cycles of said cyclically varying component.
Claim 3
Independent Claim
100 words
The method of storing information comprising: forming a device having a substrate, an insulating layer on said substrate, an electric charge capture layer on said insulating layer, and an electrode layer on said electric charge capture layer; and setting a threshold voltage of said semiconductor memory device by applying a predetermined voltage to said device to inject an electric charge into said electric charge capture layer from said substrate, having a unidirectional component corresponding to said threshold voltage to be set and a cyclically varying component at least the amplitude or pulse length of which is gradually diminished with time.
Claim 4
Independent Claim
100 words
The method of storing information comprising: forming a device having a substrate, an insulating layer on said substrate, an electric charge capture layer on said insulating layer, and an electrode layer on said electric charge capture layer; and setting a threshold voltage of said semiconductor memory device by applying a predetermined voltage to said device to inject an electric charge into said electric charge capture layer from said substrate, having a unidirectional component corresponding to said threshold voltage to be set and a cyclically varying component at least the amplitude or pulse length of which is gradually diminished with time.
Claim 5
Dependent Claim
23 words
The method in accordance with claim 2 wherein: said substrate is a semiconductor and said insulating layer is an oxide of said semiconductor.
Claim 6
Dependent Claim
19 words
The method in accordance with claim 3 wherein: said electric charge capture layer is a nitride of said semiconductor.
Claim 7
Dependent Claim
28 words
The method in accordance with claim 3 wherein: said step of setting said threshold voltage comprises applying a predetermined voltage between said electrode layer and said semiconductor substrate.
Claim 8
Dependent Claim
32 words
The method in accordance with claim 2 wherein: said unidirectional component corresponding to said threshold voltage to be set is applied for a time duration substantially equal to said cyclically varying component.
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) | 1980-11-07 | 1981-05-09 | 1981-11-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-11-07 | 1985-05-09 | 1985-11-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-11-07 | 1989-05-09 | 1989-11-08 | $7700.00 | Window Closed / Lapsed |