US3590337A
Expired / Lapsed
US
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Plural dielectric layered electrically alterable non-destructive readout memory element
Assignee: Unisys Corp
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Filing: 1968-10-14
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Granted: 1971-06-29
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Expires: 1988-10-14
Abstract
Abstract A memory element comprising a semiconductor substrate and a conductive electrode separated from said substrate by a plurality of dielectric layers of different conductivities. The ''''writein'''' and ''''storage time'''' characteristics of the memory element are determined by the permittivity, the electric field and the current density versus electric field characteristic of the most conductive dielectric layer. The ratio of the conductivities of the most conductive dielectric layer to a contiguous dielectric layer is more than 2. The current density versus electric field characteristic of each dielectric layer is highly nonlinear. One form of the invention is a capacitor; another form is a field effect transistor utilizing said capacitor as the gate electrode structure.
Inventors
- 👤 Horst A R Wegener
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:37
CPC Classifications
G; G11; G11C; G11C16/00; G11C16/02; G11C16/04; G11C16/0466; G11C11/00; G11C11/21; G11C11/34; G11C11/40; G11C11/401; G11C11/403; G11C11/404; H; H10; H10D; H10D30/00; H10D30/60; H10D30/69
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
220 words
A memory element comprising, a semiconductor substrate, a conductive electrode, and a dielectric body comprising a plurality of contiguous layers of dielectric material separating said substrate from said electrode, said dielectric layers being arranged so that an electric field will be established across said layers when a potential is applied between said semiconductor substrate and said conductive electrode, each of the dielectric layers being selected to provide layers Each having prescribed individual electrical properties and contiguous layers having prescribed relative electrical properties, all prerequisites being essential to the formation of an element having a memory of determinable life extent, and said individual electrical properties and said relative electrical properties being those in accordance with all of said prerequisites such that a. each layer exhibits a current density versus electric field characteristic that is highly nonlinear, b. the conductivities of two contiguous layers are different, c. the ratio of the conductivity of the more conductive layer of the two contiguous layers to that of the contiguous layer is greater than 2:1, and d. the layer of greater conductivity has a ratio of permittivity times voltage gradient to resulting current density corresponding to a predetermined short write-in time; said memory element being characterized by its predeterminable short interval write-in time and its relatively long interval charge retention time under given applied fields.
Claim 2
Dependent Claim
220 words
A memory element comprising, a semiconductor substrate, a conductive electrode, and a dielectric body comprising a plurality of contiguous layers of dielectric material separating said substrate from said electrode, said dielectric layers being arranged so that an electric field will be established across said layers when a potential is applied between said semiconductor substrate and said conductive electrode, each of the dielectric layers being selected to provide layers Each having prescribed individual electrical properties and contiguous layers having prescribed relative electrical properties, all prerequisites being essential to the formation of an element having a memory of determinable life extent, and said individual electrical properties and said relative electrical properties being those in accordance with all of said prerequisites such that a. each layer exhibits a current density versus electric field characteristic that is highly nonlinear, b. the conductivities of two contiguous layers are different, c. the ratio of the conductivity of the more conductive layer of the two contiguous layers to that of the contiguous layer is greater than 2:1, and d. the layer of greater conductivity has a ratio of permittivity times voltage gradient to resulting current density corresponding to a predetermined short write-in time; said memory element being characterized by its predeterminable short interval write-in time and its relatively long interval charge retention time under given applied fields.
Claim 3
Dependent Claim
155 words
A memory element comprising a semiconductor substrate, a conductive electrode, and a plurality of contiguous layers of dielectric material separating said substrate from said electrode, one of said layers of dielectric material being silicon nitride and another of said layers of dielectric materials being silicon oxynitride, the ratio of the conductivities of the most conductive dielectric layer to a contiguous dielectric layer being more than 2, said most conductive dielectric layer having a ratio of permittivity times voltage gradient to resulting current density sufficient to provide a write-in time of less than about 100 milliseconds, the current density versus electric field characteristics of each dielectric layer being highly nonlinear, whereby electric charge forms at the interface between said most conductive dielectric layer and said contiguous dielectric layer in a short time under the influence of a relatively high electric field and in a disproportionately long time under the influence of a relatively low electric field.
Claim 4
Dependent Claim
155 words
A memory element comprising a semiconductor substrate, a conductive electrode, and a plurality of contiguous layers of dielectric material separating said substrate from said electrode, one of said layers of dielectric material being silicon nitride and another of said layers of dielectric materials being silicon oxynitride, the ratio of the conductivities of the most conductive dielectric layer to a contiguous dielectric layer being more than 2, said most conductive dielectric layer having a ratio of permittivity times voltage gradient to resulting current density sufficient to provide a write-in time of less than about 100 milliseconds, the current density versus electric field characteristics of each dielectric layer being highly nonlinear, whereby electric charge forms at the interface between said most conductive dielectric layer and said contiguous dielectric layer in a short time under the influence of a relatively high electric field and in a disproportionately long time under the influence of a relatively low electric field.
Claim 5
Dependent Claim
103 words
A memory element comprising, a semiconductor substrate, a conductive electrode, and a plurality of contiguous layers of dielectric material separating said substrate from said electrode, one of said layers of dielectric material being silicon nitride and another of said layers of dielectric material being silicon oxynitride, the ratio of conductivities of the most conductive dielectric layer to a contiguous dielectric layer being more than 2, said most conductive dielectric layer having a ratio of permittivity times voltage gradient to resulting current density sufficient to provide a short write-in time, the current density versus electric field characteristics of each dielectric layer being highly nonlinear.
Claim 6
Dependent Claim
103 words
A memory element comprising, a semiconductor substrate, a conductive electrode, and a plurality of contiguous layers of dielectric material separating said substrate from said electrode, one of said layers of dielectric material being silicon nitride and another of said layers of dielectric material being silicon oxynitride, the ratio of conductivities of the most conductive dielectric layer to a contiguous dielectric layer being more than 2, said most conductive dielectric layer having a ratio of permittivity times voltage gradient to resulting current density sufficient to provide a short write-in time, the current density versus electric field characteristics of each dielectric layer being highly nonlinear.
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) | 1974-06-28 | 1974-12-28 | 1975-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-28 | 1978-12-28 | 1979-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-28 | 1982-12-28 | 1983-06-29 | $7700.00 | Window Closed / Lapsed |