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Single-electrode charge-coupled random access memory cell

Assignee: International Business Machines Corp
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Filing: 1973-09-24
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Granted: 1977-03-22
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Expires: 1993-09-24
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Abstract

Abstract A charge-coupled random access memory cell is formed in a semiconductor body divided into three adjacent regions. The first region has an impurity diffused therein and serves alternately as a source and a drain for charge carriers. The second or gate region has a predetermined threshold voltage and the third or storage region has a lower threshold voltage. A single unitary metal electrode extends in superimposed relation to the second and third regions. Upon the application of potentials to the first region and the electrode, charge carriers may be stored in or removed from the third region so as to write a "1" or a "0" in the cell.

Inventors

  • 👤 Irving T. Ho
  • 👤 Hwa N. Yu

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-24 11:58
CPC Classifications
G; G11; G11C; G11C16/00; G11C16/02; G11C16/04; G11C16/0466; H; H10; H10B; H10B12/00; H10B12/30; H10D; H10D44/00; H10D44/40; H10D44/45; H10D62/00; H10D62/10; H10D62/17; H10D62/213; H10D62/335

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 393 words
A charge coupled random access memory array comprising: a semiconductor body having therein an impurity of a first conductivity type, a plurality of charge couple memory cells arranged in columns and rows on said body, bit lines extending in the column direction, each bit line in operative relation to a column of said cells, word lines extending in the row direction, each word line in operative relation to a row of said cells, each of said cells comprised of a first region in said semiconductor body having embodied therein an impurity of a second opposite conductivity type, said first region of said cell in operative electrical connection with one of said bit lines, a second region in said body in adjacent lateral relationship to said first region in the row direction, a third region in said body in adjacent lateral relationship to said second region, and spaced from said first region by said second region, said third region spaced from the first region of the adjacent memory cell, a surface layer of dielectric material overlying at least said second region and said third region, means associated with said dielectric layer providing said second region with a first predetermined threshold voltage, and said third region with a second threshold voltage less in absolute magnitude than said first predetermined threshold voltage, a single conductive electrode on said surface layer of dielectric material and extending over said second and third regions in superimposed relation and in operative electrical connection with one of said word lines, said single electrode having a first portion over said second region of said body, and a second portion over said third region of said body, a means of applying at least two voltage levels to said conductive electrode to control the storage of charges in, and flow of charges to, said third region, the first of said voltage levels applied to said conductive electrode is of an absolute magnitude less than said first predetermined threshold voltage of said second region, but equal to or greater than said second threshold voltage of said third region, thereby inverting only said third region for charge storage capability, the second of said voltage levels of an absolute magnitude equal to or greater than said first predetermined threshold voltage of said second region thereby inverting both of said second and third regions for charge flow capability.
Claim 2
Dependent Claim 393 words
A charge coupled random access memory array comprising: a semiconductor body having therein an impurity of a first conductivity type, a plurality of charge couple memory cells arranged in columns and rows on said body, bit lines extending in the column direction, each bit line in operative relation to a column of said cells, word lines extending in the row direction, each word line in operative relation to a row of said cells, each of said cells comprised of a first region in said semiconductor body having embodied therein an impurity of a second opposite conductivity type, said first region of said cell in operative electrical connection with one of said bit lines, a second region in said body in adjacent lateral relationship to said first region in the row direction, a third region in said body in adjacent lateral relationship to said second region, and spaced from said first region by said second region, said third region spaced from the first region of the adjacent memory cell, a surface layer of dielectric material overlying at least said second region and said third region, means associated with said dielectric layer providing said second region with a first predetermined threshold voltage, and said third region with a second threshold voltage less in absolute magnitude than said first predetermined threshold voltage, a single conductive electrode on said surface layer of dielectric material and extending over said second and third regions in superimposed relation and in operative electrical connection with one of said word lines, said single electrode having a first portion over said second region of said body, and a second portion over said third region of said body, a means of applying at least two voltage levels to said conductive electrode to control the storage of charges in, and flow of charges to, said third region, the first of said voltage levels applied to said conductive electrode is of an absolute magnitude less than said first predetermined threshold voltage of said second region, but equal to or greater than said second threshold voltage of said third region, thereby inverting only said third region for charge storage capability, the second of said voltage levels of an absolute magnitude equal to or greater than said first predetermined threshold voltage of said second region thereby inverting both of said second and third regions for charge flow capability.
Claim 3
Dependent Claim 23 words
A charge-coupled random access memory array as recited in claim 1 and comprising means for sensing the charge stored in said third region.
Claim 4
Dependent Claim 56 words
A charge-coupled random access memory array as recited in claim 1 and comprising an insulating layer extending between said electrode and said semiconductor body, said insulating layer having a predetermined thickness between said electrode and said second region, said insulating layer having between said electrode and said third region a thickness less than said predetermined thickness.
Claim 5
Dependent Claim 18 words
A charge-coupled random access memory array as recited in claim 3 wherein said insulating layer comprises silicon dioxide.
Claim 6
Dependent Claim 23 words
A charge-coupled random access memory array as recited in claim 4 and comprising: means for sensing the charge stored in said third region.
Claim 7
Dependent Claim 50 words
A charge coupled random access memory array as recited in claim 1 comprising a preamplifier and a sense amplifier connected to each of said bit lines, a decoder connected to said preamplifiers, a word driver connected to each of said word lines, and a decoder connected to said word drivers.

References Cited (Backward Citations)

US3533089A Cited
US3651349A Cited
US3654499A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1980-03-21 1980-09-20 1981-03-22 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1984-03-21 1984-09-20 1985-03-22 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1988-03-21 1988-09-20 1989-03-22 $7700.00 Window Closed / Lapsed

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