Patent US4638460A successfully refreshed from Google Patents.
US4638460A
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US
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Semiconductor memory device
Assignee: Hitachi Ltd
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Filing: 1983-09-07
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Granted: 1987-01-20
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Expires: 2003-09-07
Abstract
Abstract A semiconductor memory device is provided with memory cells which each comprises an insulated gate type field effect transistor and a capacitor connected in series with one another and connected to bit lines. The capacitor is composed of a pair of electrodes and a dielectric film which includes a silicon nitride film existing between the pair of electrodes. One electrode of the capacitor is provided with a terminal to which a voltage is applied. The value of the applied voltage is chosen so that the voltage applied between the pair of electrodes is smaller in an absolute value than a voltage applied to the bit line.
Inventors
- 👤 Tetsuro Matsumoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:49
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/21; G11C11/34; G11C11/40; G11C11/401; G11C11/403; G11C11/404; H; H10; H10B; H10B12/00; H10B12/30; H10D; H10D84/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
156 words
A semiconductor memory device comprising: a memory cell which includes a series connection comprised of a switching MISFET and a storage capacitor connected in series, said storage capacitor being comprised of a semiconductor region of a semiconductor substrate, a silicon nitride film formed over a surface of said semiconductor region, and a conductive layer formed over said silicon nitride film; a bit line which is connected to one end of said series connection and which supplies a signal voltage having a predetermined maximum value to said memory cell; and a terminal which is connected to the other end of said series connection and which supplies a voltage to said other end of said series connection so that a voltage of said storage capacitor to be stored between said semicoductor region and said conductive layer has a smaller absolute value than an absolute value of said maximum value of said signal voltage supplied to said bit line.
Claim 2
Dependent Claim
156 words
A semiconductor memory device comprising: a memory cell which includes a series connection comprised of a switching MISFET and a storage capacitor connected in series, said storage capacitor being comprised of a semiconductor region of a semiconductor substrate, a silicon nitride film formed over a surface of said semiconductor region, and a conductive layer formed over said silicon nitride film; a bit line which is connected to one end of said series connection and which supplies a signal voltage having a predetermined maximum value to said memory cell; and a terminal which is connected to the other end of said series connection and which supplies a voltage to said other end of said series connection so that a voltage of said storage capacitor to be stored between said semicoductor region and said conductive layer has a smaller absolute value than an absolute value of said maximum value of said signal voltage supplied to said bit line.
Claim 3
Dependent Claim
27 words
A semiconductor memory device according to claim 1, wherein said silicon nitride film is formed on a silicon oxide film which is formed on said semiconductor region.
Claim 4
Dependent Claim
25 words
A semiconductor memory device according to claim 1, wherein a voltage substantially equal to half of said maximum signal voltage is applied to said terminal.
Claim 5
Dependent Claim
25 words
A semiconductor memory device according to claim 2, wherein a voltage substantially equal to half of said maximum signal voltage is applied to said terminal.
Claim 6
Dependent Claim
175 words
A semiconductor memory device comprising: a memory cell which includes a series connection comprised of a switching MISFET and a storage capacitor connected in series, said storage capacitor being comprised of a semiconductor region of a semiconductor substrate, a silicon nitride film formed over a surface of said semiconductor region, and a conductive layer formed over said silicon nitride film; a bit line which is connected to one end of said series connection and which supplies a signal voltage having a predetermined high level V H and a predetermined low level V L to said memory cell; and a terminal which is connected to the other end of said series connection and which supplied a voltage V P which is greater than V L but less than V H to said other end of said series connection so that a voltage V S of said storage capacitor to be stored between said semiconductor region and said conductive layer has a smaller absolute value than the absolute value of V H supplied to said bit line.
Claim 7
Dependent Claim
175 words
A semiconductor memory device comprising: a memory cell which includes a series connection comprised of a switching MISFET and a storage capacitor connected in series, said storage capacitor being comprised of a semiconductor region of a semiconductor substrate, a silicon nitride film formed over a surface of said semiconductor region, and a conductive layer formed over said silicon nitride film; a bit line which is connected to one end of said series connection and which supplies a signal voltage having a predetermined high level V H and a predetermined low level V L to said memory cell; and a terminal which is connected to the other end of said series connection and which supplied a voltage V P which is greater than V L but less than V H to said other end of said series connection so that a voltage V S of said storage capacitor to be stored between said semiconductor region and said conductive layer has a smaller absolute value than the absolute value of V H supplied to said bit line.
Claim 8
Dependent Claim
16 words
A semiconductor memory device according to claim 5, wherein V P =V H +V L /2.
References Cited (Backward Citations)
US4322881A
Cited
US4456978A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1990-01-19 | 1990-07-21 | 1991-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-19 | 1994-07-21 | 1995-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-19 | 1998-07-21 | 1999-01-20 | $7700.00 | Window Closed / Lapsed |