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US6104633A Expired / Lapsed US ⏱️ 0.0 years remaining

Intentional asymmetry imposed during fabrication and/or access of magnetic tunnel junction devices

Assignee: GlobalFoundries Inc
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Filing: 1998-02-10
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Granted: 2000-08-15
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Expires: 2018-02-10
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Abstract

Abstract Magnetic memory cells include a changeable magnetic region with a magnetic axis along which two directions of magnetization can be imposed, thereby providing two respective states into which the cells are changeable according to electrical and resultant magnetic stimuli applied thereto. Asymmetry in the magnetic stimuli applied to the cell while writing a state therein is disclosed to provide a predictable magnetization pattern evolution from the first direction to the second direction. Physical asymmetry in the layout and/or magnetization of the cell is also disclosed which provides the predictable pattern evolution. These principles can be applied to magnetic random access memory (MRAM) arrays which employ magnetic tunnel junction (MTJ) cells at the intersections of bitlines and wordlines which supply the electrical and resultant magnetic stimuli to write the cells therein.

Inventors

  • 👤 David William Abraham
  • 👤 William Joseph Gallagher
  • 👤 Philip Louis Trouilloud

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-03 19:09
CPC Classifications
H; H10; H10B; H10B61/00; H10B61/10; G; G11; G11C; G11C11/00; G11C11/02; G11C11/16; G11C11/161; G11C11/165; G11C11/1653; G11C11/1675; H10D; H10D84/00; H10D84/01; H10D84/0123; H10D84/0126; H10D84/0144; H10N; H10N59/00

Claims Analysis

Total Claims: 27
Claim 1
Independent Claim 81 words
A magnetic memory, comprising: first and second crossing conductive lines forming an intersecting region; and a magnetic memory cell disposed at said intersecting region and comprising a changeable magnetic region with a magnetic axis along which two directions of magnetization can be imposed, thereby providing two respective states into which the cell is changeable according to magnetic stimuli applied thereto via the first and second crossing conductive lines, the changeable magnetic region being substantially magnetically asymmetrically shaped about its magnetic axis.
Claim 2
Dependent Claim 81 words
A magnetic memory, comprising: first and second crossing conductive lines forming an intersecting region; and a magnetic memory cell disposed at said intersecting region and comprising a changeable magnetic region with a magnetic axis along which two directions of magnetization can be imposed, thereby providing two respective states into which the cell is changeable according to magnetic stimuli applied thereto via the first and second crossing conductive lines, the changeable magnetic region being substantially magnetically asymmetrically shaped about its magnetic axis.
Claim 3
Dependent Claim 34 words
The magnetic memory of claim 1, wherein the changeable magnetic region of the magnetic memory cell is shaped as a substantially planar parallelogram about its magnetic axis with non-right angles in the corners thereof.
Claim 4
Dependent Claim 35 words
The magnetic memory of claim 1, wherein the magnetic memory cell is disposed in the intersecting region such that the magnetic axis thereof is parallel to one of the first and second crossing conductive lines.
Claim 5
Dependent Claim 24 words
The magnetic memory of claim 1, wherein the changeable magnetic region is magnetically asymmetrically shaped about its magnetic axis via a built-in magnetic anisotropy.
Claim 6
Dependent Claim 31 words
The magnetic memory of claim 1, further comprising: a magnetic bias region proximate the changeable magnetic region to provide a bias to provide the magnetically asymmetric shape about said magnetic axis.
Claim 7
Dependent Claim 96 words
The magnetic memory of claim 5, wherein the changeable magnetic region is shaped substantially as a square having the magnetic axis aligned between a first pair of opposing corners of the square, and wherein the bias is aligned along a second pair of opposing corners of the square, wherein the bias maintains a common direction of magnetization at all four corners of the square thereby providing the magnetic asymmetry of the changeable magnetic region about the magnetic axis, and wherein the two directions of magnetization are imposed in the interior portion of the square changeable region.
Claim 8
Dependent Claim 90 words
The magnetic memory of claim 1, further comprising: first and second pluralities of crossing conductive lines, including said first and second crossing conductive lines, forming a plurality of intersecting regions, including said intersecting region; and a plurality of magnetic memory cells, including said magnetic memory cell, each disposed at a respective one of the plurality of intersecting regions and each being substantially magnetically asymmetrically shaped about a magnetic axis thereof along which two directions of magnetization can be imposed to provide two respective states into which each cell is changeable.
Claim 9
Dependent Claim 20 words
The magnetic memory of claim 1, wherein the two directions of magnetization along the magnetic axis directly oppose one another.
Claim 10
Dependent Claim 20 words
The magnetic memory of claim 1, wherein the magnetic memory cell is formed from at least one magnetic tunnel junction.
Claim 11
Dependent Claim 87 words
A magnetic memory, comprising: first and second crossing conductive lines forming an intersecting region; and a magnetic memory cell disposed at said intersecting region and having a magnetic axis along which two directions of magnetization can be imposed thereby providing two respective states into which the cell is changeable according to magnetic stimuli applied thereto via the first and second crossing conductive lines, the cell disposed in said intersecting region such that said magnetic axis is non-parallel to either said first or said second crossing conductive line.
Claim 12
Dependent Claim 87 words
A magnetic memory, comprising: first and second crossing conductive lines forming an intersecting region; and a magnetic memory cell disposed at said intersecting region and having a magnetic axis along which two directions of magnetization can be imposed thereby providing two respective states into which the cell is changeable according to magnetic stimuli applied thereto via the first and second crossing conductive lines, the cell disposed in said intersecting region such that said magnetic axis is non-parallel to either said first or said second crossing conductive line.
Claim 13
Dependent Claim 132 words
The magnetic memory of claim 10, further comprising: first and second pluralities of crossing conductive lines, including said first and second crossing conductive lines, forming a plurality of intersecting regions, including said intersecting region; and a plurality of magnetic memory cells, including said magnetic memory cell, each disposed at a respective one of said plurality of intersecting regions and each having a magnetic axis along which two directions of magnetization can be imposed thereby providing two respective states into which each cell is changeable according to magnetic stimuli applied thereto via the respective first and second crossing conductive lines forming the respective intersecting region, each respective cell disposed in its respective intersecting region such that its magnetic axis is non-parallel to either its respective first or its respective second crossing conductive line.
Claim 14
Dependent Claim 29 words
The magnetic memory of claim 10, wherein the magnetic axis forms an angle of greater than about 5 degrees with either said first or said second crossing conductive line.
Claim 15
Dependent Claim 77 words
In a magnetic memory having a magnetic memory cell therein which includes a changeable magnetic region with a magnetic axis along which two directions of magnetization can be imposed, thereby providing two respective states into which the cell is changeable according to magnetic stimuli applied thereto, a method for changing the changeable magnetic region between the two directions of magnetization, comprising: applying the magnetic stimuli to the changeable region in a direction non-parallel to the magnetic axis.
Claim 16
Dependent Claim 77 words
In a magnetic memory having a magnetic memory cell therein which includes a changeable magnetic region with a magnetic axis along which two directions of magnetization can be imposed, thereby providing two respective states into which the cell is changeable according to magnetic stimuli applied thereto, a method for changing the changeable magnetic region between the two directions of magnetization, comprising: applying the magnetic stimuli to the changeable region in a direction non-parallel to the magnetic axis.
Claim 17
Dependent Claim 38 words
The method of claim 13, wherein said applying includes using a line arranged relative to said magnetic axis such that the resultant magnetic stimuli is applied to the changeable region in the direction non-parallel to the magnetic axis.
Claim 18
Dependent Claim 26 words
The method of claim 14, wherein the line and the changeable magnetic region are arranged such that the magnetic axis is not perpendicular to the line.
Claim 19
Dependent Claim 32 words
The method of claim 15, wherein the line and the changeable magnetic region are arranged such that the magnetic axis is not perpendicular to the line by more than about 5 degrees.
Claim 20
Dependent Claim 45 words
The method of claim 13, wherein said applying includes: using first and second magnetic stimuli from respective first and second lines crossing proximate said cell, said direction of said magnetic stimuli attained according to respective magnitudes and/or timing of the first and second magnetic stimuli.
Claim 21
Dependent Claim 71 words
The method of claim 17, wherein said using first and second magnetic stimuli includes: simultaneously sweeping both the first and second magnetic stimuli from respective first values to respective second values such that the intervening values of the second magnetic stimuli comprise a fixed percentage of the respective intervening values of the first magnetic stimuli, thereby resulting in the magnetic stimuli being applied in said direction non-parallel to the magnetic axis.
Claim 22
Dependent Claim 25 words
The method of claim 18, wherein said fixed percentage is about 10%, such that said direction non-parallel to the magnetic axis is about 5 degrees.
Claim 23
Dependent Claim 43 words
The method of claim 18, wherein the first and second lines cross perpendicular to each other proximate said cell such that the first and second magnetic stimuli are applied perpendicular to each other, one of said lines being parallel to said magnetic axis.
Claim 24
Dependent Claim 107 words
In a magnetic memory having a magnetic memory cell therein which includes a changeable magnetic region with a magnetic axis along which two directions of magnetization can be imposed, thereby providing two respective states into which the cell is changeable according to magnetic stimuli applied thereto, a method for changing the changeable magnetic region between the two directions of magnetization, comprising: applying the magnetic stimuli to the changeable region, including using first and second magnetic stimuli from respective first and second lines crossing proximate said cell, said direction of the magnetic stimuli attained according to respectively varying amplitudes and/or timing of the first and second magnetic stimuli.
Claim 25
Dependent Claim 107 words
In a magnetic memory having a magnetic memory cell therein which includes a changeable magnetic region with a magnetic axis along which two directions of magnetization can be imposed, thereby providing two respective states into which the cell is changeable according to magnetic stimuli applied thereto, a method for changing the changeable magnetic region between the two directions of magnetization, comprising: applying the magnetic stimuli to the changeable region, including using first and second magnetic stimuli from respective first and second lines crossing proximate said cell, said direction of the magnetic stimuli attained according to respectively varying amplitudes and/or timing of the first and second magnetic stimuli.
Claim 26
Dependent Claim 37 words
The method of claim 21, wherein said using first and second magnetic stimuli includes: sweeping the first magnetic stimulus from a first value to a second value while holding the second magnetic stimulus to a constant value.
Claim 27
Dependent Claim 43 words
The method of claim 22, wherein the first and second lines cross perpendicular to each other proximate said cell such that the first and second magnetic stimuli are applied perpendicular to each other, one of said lines being parallel to said magnetic axis.

References Cited (Backward Citations)

US5341118A Cited
US5408377A Cited
US5640343A Cited
US5650958A Cited
US5838608A Cited
US5946228A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2003-08-15 2004-02-14 2004-08-15 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2007-08-15 2008-02-14 2008-08-15 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2011-08-15 2012-02-14 2012-08-15 $7700.00 Window Closed / Lapsed

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