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US5608250A Expired / Lapsed US ⏱️ 0.0 years remaining

Volatile memory cell with interface charge traps

Assignee: STMicroelectronics SA
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Filing: 1994-11-21
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Granted: 1997-03-04
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Expires: 2014-11-21
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Abstract

Abstract A semiconductor device is described, incorporating electron traps at the interface between a semiconductor substrate and a gate dielectric layer of an insulated gate field effect transistor, such device being capable of retaining charge in the electron traps for a certain time, allowing volatile memory circuits to be produced wherein each cell occupies only the area required for a single transistor.

Inventors

  • 👤 Alexander Kalnitsky

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 08:45
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/21; G11C11/34; G11C11/39; H; H10; H10D; H10D30/00; H10D30/60; H10D30/69; Y; Y10; Y10S; Y10S257/00; Y10S257/903; Y10S438/00; Y10S438/91; Y10S438/953

Claims Analysis

Total Claims: 23
Claim 1
Independent Claim 42 words
A volatile memory cell comprising an insulated gate field effect transistor with charge traps in an insulating layer, wherein substantially all of said charge traps are located within approximately 1.0 nm of an interface between a semiconductor layer and the insulating layer.
Claim 2
Dependent Claim 42 words
A volatile memory cell comprising an insulated gate field effect transistor with charge traps in an insulating layer, wherein substantially all of said charge traps are located within approximately 1.0 nm of an interface between a semiconductor layer and the insulating layer.
Claim 3
Dependent Claim 23 words
The volatile memory cell of claim 1, wherein substantially all of said charge traps are located within approximately 0.5-0.7 nm of the interface.
Claim 4
Dependent Claim 33 words
The volatile memory cell of claim 1, wherein the semiconductor layer comprises P-type doped silicon and the insulating layer comprises a layer of silicon dioxide containing implanted silicon ions forming said charge traps.
Claim 5
Dependent Claim 21 words
The volatile memory cell of claim 1 wherein the semiconductor layer comprises Indium Phosphide and the insulating layer comprises Silicon Nitride.
Claim 6
Dependent Claim 34 words
A volatile memory device comprising a plurality of memory cells according to claim 1, arranged in rows and columns to allow addressing of individual cells by control circuitry connected to said volatile memory device.
Claim 7
Dependent Claim 28 words
The volatile memory cell of claim 1, wherein: a trap energy level of the charge traps has a value close to an edge of a silicon conduction band.
Claim 8
Dependent Claim 55 words
A semiconductor device comprising: a semiconductor layer; an insulating layer disposed on the semiconductor layer defining an interface between the semiconductor layer and the insulating layer; charge traps located in the insulating layer, said charge traps for retaining charge; wherein substantially all of the charge traps are located within approximately 1.0 nm from the interface.
Claim 9
Dependent Claim 55 words
A semiconductor device comprising: a semiconductor layer; an insulating layer disposed on the semiconductor layer defining an interface between the semiconductor layer and the insulating layer; charge traps located in the insulating layer, said charge traps for retaining charge; wherein substantially all of the charge traps are located within approximately 1.0 nm from the interface.
Claim 10
Dependent Claim 48 words
A memory device comprising: a semiconductor layer; an insulating layer disposed on the semiconductor layer defining an interface between the semiconductor layer and the insulating layer; charge traps located in the insulating layer; wherein substantially all of said charge traps are located within 1.0 nm of the interface.
Claim 11
Dependent Claim 48 words
A memory device comprising: a semiconductor layer; an insulating layer disposed on the semiconductor layer defining an interface between the semiconductor layer and the insulating layer; charge traps located in the insulating layer; wherein substantially all of said charge traps are located within 1.0 nm of the interface.
Claim 12
Dependent Claim 22 words
The semiconductor device of claim 7, wherein substantially all of the charge traps are located within, approximately 0.5-0.7 nm of the interface.
Claim 13
Dependent Claim 63 words
A memory device comprising: an insulated gate field effect transistor including an insulating layer having a common interface with a semiconductor substrate, charge traps located in the insulating layer, said charge traps for retaining charge, wherein substantially all of said charge traps are located within approximately 1.0 nm of said common interface, and wherein said retained charge modulates a threshold of the transistor.
Claim 14
Dependent Claim 63 words
A memory device comprising: an insulated gate field effect transistor including an insulating layer having a common interface with a semiconductor substrate, charge traps located in the insulating layer, said charge traps for retaining charge, wherein substantially all of said charge traps are located within approximately 1.0 nm of said common interface, and wherein said retained charge modulates a threshold of the transistor.
Claim 15
Dependent Claim 22 words
The memory device of claim 10, wherein substantially all of the charge traps are located within approximately 0.5-0.7 nm of the interface.
Claim 16
Dependent Claim 97 words
A memory device comprising: an insulated gate field effect transistor including an insulating layer disposed on a semiconductor substrate; charge traps located in the insulating layer, said charge traps for retaining charge for a finite period of time; said retained charge modulating a threshold of the transistor; wherein substantially all of the charge traps are located within approximately 1.0 nm of an interface between the insulating layer and the substrate; and wherein the finite period of time is a function of a density of the charge traps in the insulating layer and the distance to the interface.
Claim 17
Dependent Claim 97 words
A memory device comprising: an insulated gate field effect transistor including an insulating layer disposed on a semiconductor substrate; charge traps located in the insulating layer, said charge traps for retaining charge for a finite period of time; said retained charge modulating a threshold of the transistor; wherein substantially all of the charge traps are located within approximately 1.0 nm of an interface between the insulating layer and the substrate; and wherein the finite period of time is a function of a density of the charge traps in the insulating layer and the distance to the interface.
Claim 18
Dependent Claim 108 words
A memory circuit comprising: a control circuit for reading and writing to individual memory cells; and a plurality of memory cells arranged in rows and columns to allow addressing of individual cells by the control circuit; each of said memory cells comprising an insulated gate field effect transistor with charge traps in an insulating layer, wherein substantially all of the charge traps are located within approximately 1.0 nm of an interface between a semiconductor layer and the insulating layer; and wherein, for each transistor, a gate is connected to a wordline, a source is connected to a first bit-line and a drain is connected to a second bit-line.
Claim 19
Dependent Claim 108 words
A memory circuit comprising: a control circuit for reading and writing to individual memory cells; and a plurality of memory cells arranged in rows and columns to allow addressing of individual cells by the control circuit; each of said memory cells comprising an insulated gate field effect transistor with charge traps in an insulating layer, wherein substantially all of the charge traps are located within approximately 1.0 nm of an interface between a semiconductor layer and the insulating layer; and wherein, for each transistor, a gate is connected to a wordline, a source is connected to a first bit-line and a drain is connected to a second bit-line.
Claim 20
Dependent Claim 22 words
The memory circuit of claim 13, wherein substantially all of the charge traps are located within approximately 0.5-0.7 nm of the interface.
Claim 21
Dependent Claim 129 words
The memory circuit comprising: a control circuit for reading and writing to individual memory cells; and a plurality of memory cells arranged in rows and columns to allow addressing of individual cells by the control circuit, each of said memory cells comprising an insulated gate field effect transistor with charge traps in an insulating layer, said charge traps for retaining charge at or near an interface between a semiconductor layer and the insulating layer, said retained charge for modulating a threshold of the transistor; wherein substantially all of the change traps are located within approximately 1.0 nm of the interface; and wherein, for each transistor, a gate is connected to a wordline, a source is connected to a first bit-line and a drain is connected to a second bit-line.
Claim 22
Dependent Claim 129 words
The memory circuit comprising: a control circuit for reading and writing to individual memory cells; and a plurality of memory cells arranged in rows and columns to allow addressing of individual cells by the control circuit, each of said memory cells comprising an insulated gate field effect transistor with charge traps in an insulating layer, said charge traps for retaining charge at or near an interface between a semiconductor layer and the insulating layer, said retained charge for modulating a threshold of the transistor; wherein substantially all of the change traps are located within approximately 1.0 nm of the interface; and wherein, for each transistor, a gate is connected to a wordline, a source is connected to a first bit-line and a drain is connected to a second bit-line.
Claim 23
Dependent Claim 21 words
The memory circuit of claim 15, wherein substantially all the charge traps are located within approximately 0.5-0.7 nm of the interface.

References Cited (Backward Citations)

US3856587A Cited
US4217601A Cited
USRE31083E Cited
US4868618A Cited
EP0342778A1 Cited
EP0451389A1 Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2000-03-03 2000-09-02 2001-03-04 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2004-03-03 2004-09-02 2005-03-04 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2008-03-03 2008-09-02 2009-03-04 $7700.00 Window Closed / Lapsed

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