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WO2005020326A1 - Cellule de memoire magnetique et dispositif a memoire magnetique - Google Patents

Cellule de memoire magnetique et dispositif a memoire magnetique Download PDF

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Publication number
WO2005020326A1
WO2005020326A1 PCT/JP2004/011830 JP2004011830W WO2005020326A1 WO 2005020326 A1 WO2005020326 A1 WO 2005020326A1 JP 2004011830 W JP2004011830 W JP 2004011830W WO 2005020326 A1 WO2005020326 A1 WO 2005020326A1
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WO
WIPO (PCT)
Prior art keywords
magnetic
layer
magneto
layers
magnetic layer
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Ceased
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PCT/JP2004/011830
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English (en)
Japanese (ja)
Inventor
Susumu Haratani
Keiji Koga
Joichiro Ezaki
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TDK Corp
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TDK Corp
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Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11C—STATIC STORES
    • G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
    • G11C11/02—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements
    • G11C11/16—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using elements in which the storage effect is based on magnetic spin effect
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10B—ELECTRONIC MEMORY DEVICES
    • H10B61/00—Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices
    • H10B61/10—Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices comprising components having two electrodes, e.g. diodes or MIM elements

Definitions

  • the present invention relates to a magnetic memory cell including a magnetoresistive effect generator, and a magnetic memory device including a plurality of magnetic memory cells and configured to record and read information.
  • a magnetic random access memory (hereinafter, also referred to as “MRAM: Magnetic random access memory”) is known as a magnetic memory device using this type of magnetic storage cell.
  • MRAM Magnetic random access memory
  • information is stored using a combination (parallel or antiparallel) of the magnetization directions of two ferromagnetic materials included in the magnetoresistive element.
  • reading of stored information detects a change in the resistance value (ie, a change in current or voltage) of the magnetoresistive element that differs when the magnetization directions of the two ferromagnetic materials are parallel and antiparallel. It is done by doing.
  • MRAM giant magneto-resistive
  • the effect is used.
  • an MRAM using a GMR element capable of obtaining the GMR effect one disclosed in US Pat. No. 5,343,422 is known.
  • the GMR effect is a phenomenon in which the resistance value becomes minimum when the magnetization directions of two parallel magnetic layers along the easy axis direction are parallel to each other, and becomes maximum when the magnetization directions are antiparallel.
  • Means As the MRAM using the GMR element, there are a coercive force difference type (a pseudo spin valve type; a Pseudo spin valve type) and an exchange bias type (a spin valve; a spin valve type).
  • a GMR element In a coercive force difference type MRAM, a GMR element has two ferromagnetic layers and a nonmagnetic layer sandwiched between them, and writes and reads information using the coercive force difference between the two ferromagnetic materials. It is to put out.
  • the GMR element has a structure of, for example, “nickel iron alloy (NiFe) / copper (Cu) / cobalt (Co)”
  • the resistance change rate is a small value of about 6-8%.
  • exchange-bias type MRAM the GMR element has a fixed layer whose magnetization direction is fixed by exchange coupling with an antiferromagnetic layer, and the magnetization direction changes due to an external magnetic field.
  • the GMR element has a magneto-sensitive layer and a non-magnetic layer sandwiched between them, and writes and reads information by utilizing the difference in the magnetization direction between the fixed layer and the magneto-sensitive layer.
  • the configuration of the GMR element is “platinum manganese (PtMn) / cobalt iron (CoFe) / copper (Cu) / CoFeJ
  • the resistance change rate is about 10%, which is larger than the coercive force difference type.
  • it is not enough to achieve further improvement in storage speed and access speed.
  • TMR effect tunnel magnetoresistance effect
  • the MRAM includes a plurality of bit lines 105 arranged in parallel with each other, and a plurality of write lines arranged in parallel with each other and orthogonal to each bit line 105.
  • a plurality of storage elements 120 arranged in the same manner.
  • the storage element 120 includes a first magnetic layer 102, a tunnel barrier layer 103, and a magneto-sensitive layer 104 as a second magnetic layer, and these layers 102, 103, 104 Are stacked in this order.
  • the TMR effect refers to the effect between the two first magnetic layers 102 and ferromagnetic layers 104 as ferromagnetic layers sandwiching a tunnel barrier layer 103 as an extremely thin insulating layer (nonmagnetic conductive layer).
  • This is an effect that the tunnel current flowing through the tunnel barrier layer 103 changes depending on the relative angle of the magnetization direction in.
  • the resistance value becomes minimum when the magnetization directions of the first magnetic layer 102 and the magneto-sensitive layer 104 are parallel to each other, and becomes maximum when they are antiparallel to each other.
  • the resistance change rate is 40 when the storage element 120 has a structure of, for example, “CoFe / aluminum oxide / CoFe”.
  • the magnetization direction of the magneto-sensitive layer 104 in the storage element 120 is changed to a predetermined direction by a current magnetic field generated by applying a current to the bit line 105 and the write word line 106 shown in FIG. The direction is changed and the information is stored.
  • Patent Document 1 US Pat. No. 5,343,422
  • Patent Document 2 US Pat. No. 5,629,922
  • Patent Document 3 Japanese Patent Application Laid-Open No. 9-91949
  • the inventors have found the following problems. That is, in this MRAM, the magnetization direction of the magneto-sensitive layer 104 is changed by an induced magnetic field (that is, a current magnetic field) caused by a current flowing through the orthogonally arranged bit line 105 and write word line 106, and each memory cell as a storage cell is changed. Information is stored in the element 120.
  • this magnetic field is an open magnetic field (not magnetically confined to a specific area)
  • the MRAM has a large leakage flux. Is low. At the same time, there is a problem that the leakage magnetic flux may adversely affect the adjacent storage element 120.
  • FIGS. 3 and 4 [0008] Regarding this problem, the inventors have proposed a magnetic device having a structure as shown in FIGS. 3 and 4 (a).
  • Qi memory cell 1 is being developed.
  • This magnetic storage cell (hereinafter, also referred to as “storage cell”) 1 includes a pair of storage elements la and lb.
  • each storage element la, lb is formed by one or more conductors (write bit line 5a and write word line 6, write bit line 5b and write word line 6) that generate a magnetic field.
  • each of the TMR films S20a and S20b is formed by laminating a plurality of layers including a second magnetic layer (second magnetosensitive layer) 8a and 8b.
  • each of the annular magnetic layers 4a and 4b is disposed so that the direction along the laminated surface of the TMR films S20a and S20b (the direction perpendicular to the plane of the drawing) is the axial direction.
  • the axes of the annular magnetic layers 4a and 4b are indicated by reference numerals F and G in FIG. 4 (a).
  • each of the annular magnetic layers 4a and 4b is arranged side by side so that the above-mentioned axial directions are coincident with each other, and the respective conductors (the write bit line 5a and the write word line 6a) penetrate each other. And a predetermined portion (shared portion 34) sandwiched between the write bit line 5b and the write word line 6).
  • a part of the annular magnetic layer is formed.
  • the magnetic flux density in the shared portion 34 of each of the annular magnetic layers 4a and 4b can be increased as compared with a storage cell provided separately without being shared with each other, and as a result, the magnetic flux density in each of the annular magnetic layers 4a and 4b can be increased.
  • the strength of each of the return magnetic fields 16a and 16b can be increased.
  • the first magneto-sensitive layers 14a and 14b and the The magnetization reversal of the two magnetosensitive layers 8a and 8b can be performed.
  • the write current refers to a current necessary for reversing the magnetization direction of the free layer (8a and 14a, 8b and 14b).
  • a storage element for example, storage element la in FIG. 4 having one magnetoresistive effect generator 20a in FIG. 4 and one annular magnetic layer 4a in FIG.
  • the one magnetoresistive effect generator 20a also stores 1-bit information, the write bit lines 5a, 5b and 5b Since the magnetic flux generated around the write word line 6 can be confined in the closed magnetic path formed by the annular magnetic layer 4a, the generation of the leakage magnetic flux can be reduced. As a result, the adverse effect on the adjacent memory cell is greatly reduced. The writing efficiency can be increased while reducing the writing efficiency.
  • the first magneto-sensitive layers 14a and 14b formed on a part of the annular magnetic layers 4a and 4b as described above are independent magnetic layers (which form an annular structure with other magnetic layers).
  • the distribution of the current magnetic field (distribution of the direction and magnitude of the magnetic field) generated inside each of the write bit lines 5a and 5b and the write word line 6 is higher than that of the write sensitive magnetic layer. It tends to be complicated.
  • the directions of the magnetic fields at the first magneto-sensitive layers 14a and 14b where the magneto-resistance effect generators 20a and 20b are arranged are aligned. is there. Therefore, in the memory cell 1, in order to securely store information, it is important to locate each magnetoresistive effect expressing body 20a, 20b in each of the first magnetosensitive layers 14a, 14b. It is hoped that this point will be clarified.
  • the present invention has been made in view of a strong demand, and it is an object of the present invention to provide a magnetic memory cell and a magnetic memory device capable of reliably storing information while reducing generation of leakage magnetic flux by an annular magnetic layer.
  • the main purpose is.
  • the magnetic memory cell according to the present invention includes an annular magnetic layer penetrated by a plurality of conductors for generating a magnetic field, a first magnetosensitive layer in the annular magnetic layer whose magnetization direction is changed by the magnetic field, and Including the magnetoresistive effect generator provided on the surface of the magneto-sensitive layer A laminate configured to allow a current to flow in a direction perpendicular to the lamination plane, wherein the magnetoresistance effect-generating body is disposed near a central portion of the first magnetosensitive layer.
  • the “magnetic field” in the present invention means a magnetic field generated by a current flowing through a plurality of conductors or a return magnetic field generated in an annular magnetic layer.
  • annular in the “annular magnetic layer” means that when viewed from a conductor penetrating the inside, the surroundings of the conductor are completely and magnetically and completely continuously captured, and the cross section in the direction crossing the conductor is closed. Means the state that is. Therefore, the annular magnetic layer allows the insulator to be contained as long as it is magnetically and electrically continuous. In other words, the insulating film does not include an insulator through which a current does not flow, but may include an oxide film generated in a manufacturing process, for example. Further, the term “magnetoresistive effect body” means a part or an object that exhibits the magnetoresistance effect.
  • the magnetic memory cell according to the present invention includes an annular magnetic layer penetrated by a plurality of conductors for generating a magnetic field, a first magnetosensitive layer in the annular magnetic layer, the magnetization direction of which is changed by the magnetic field.
  • a plurality of storage elements each having a stacked body including a magnetoresistive effect body disposed on the surface of the first magnetically sensitive layer and configured to allow current to flow in a direction perpendicular to the stacked surface,
  • the annular magnetic layers are arranged side by side with their respective axial directions coinciding with each other, and are configured to share respective predetermined portions with each other.
  • the plurality of first magnetosensitive layers are formed on a surface including the respective axes.
  • the plurality of magnetoresistive effect exhibitors are disposed on the same side with respect to each other, and are disposed at or near a central portion of the corresponding first magnetosensitive layer.
  • the “axial direction” in this specification refers to a direction parallel to the axis of the annular magnetic layer when attention is paid to the annular magnetic layer alone, in other words, the opening direction of the annular magnetic layer, that is, the direction of the conductor passing through the inside. It means the extending direction.
  • Shared means a state in which a pair of annular magnetic layers are electrically and magnetically continuous with each other.
  • the plurality of first magnetosensitive layers are configured to be magnetized in directions antiparallel to each other by the magnetic field.
  • antiparallel to each other means that the magnetization directions of each other, that is, the relative angle formed by the average magnetization direction in each magnetic layer is strictly 180 degrees, and also occurs in manufacturing. This also includes the case where the angle deviates from 180 degrees by a predetermined angle due to an error or an error that occurs because the axis is not completely uniaxial.
  • the plurality of conductors extend in parallel with each other in a region penetrating the annular magnetic layer. It is preferred to construct the line.
  • the laminated body is configured to include a second magnetically sensitive layer that can be magnetically exchange-coupled with the first magnetically sensitive layer.
  • the “information” in the present invention is generally a binary value represented by “0”, “1” or “High”, “Low” or the like based on a current value or a voltage value in an input / output signal to a magnetic memory device. Get information.
  • the first magnetic layer using a material having a larger coercive force than the second magnetic layer.
  • a magnetic memory device includes the above-described magnetic storage cell, a write line as the conductive line, and a read line for supplying the current to the laminate.
  • the annular magnetic layer penetrated by the plurality of conductors for generating the magnetic field, the first magnetosensitive layer whose magnetization direction changes by the magnetic field in the annular magnetic layer, and A stacked body including a magnetoresistive effect body disposed on the surface of the first magneto-sensitive layer and configured to allow a current to flow in a direction perpendicular to the stacked surface.
  • the magnetic flux generated around each of these conductors by the current flowing through the plurality of conductors is formed by each annular magnetic layer. Since the magnetic flux can be confined in a closed magnetic circuit, the generation of leakage magnetic flux can be reduced by the annular magnetic layer. As a result, the adverse effect on the memory cell in P-contact can be greatly reduced. In addition, as the leakage magnetic flux decreases, the strength of the magnetic field in the first magneto-sensitive layer formed on a part of the annular magnetic layer increases. As a result, the magnetization reversal of the first magneto-sensitive layer is performed by a smaller write current. It can be carried out.
  • the magnetization direction of the first magneto-sensitive layer can be controlled.
  • the information can be securely stored.
  • the annular magnetic layer penetrated by the plurality of conductors for generating a magnetic field, and the first magnetic field in which the magnetization direction changes due to the magnetic field in the annular magnetic layer.
  • a plurality of storage elements each including a magneto-sensitive layer and a magneto-resistance effect generator disposed on the surface of the first magneto-sensitive layer and configured to allow current to flow in a direction perpendicular to the lamination plane.
  • each annular magnetic layer is arranged side by side in the same axial direction, share respective predetermined portions with each other to form each annular magnetic layer, and form a plurality of first sensors on the same side with respect to a plane including each axis.
  • a comparison is made with a configuration in which the annular magnetic layers are separated from each other.
  • As a common part of each annular magnetic layer It is possible to increase the magnetic flux density in the constant region, each the reflux intensity of the magnetic field in each of the annular magnetic layer can be further enhanced.
  • the magnetization reversal of the first magneto-sensitive layer can be efficiently performed with a smaller write current, together with the reduction of the generation of the leakage magnetic flux. Furthermore, by arranging the magnetoresistive effect generator at or near the center of the first magnetosensitive layer in which the direction and intensity of the magnetic field are uniform, the magnetization direction of the first magnetosensitive layer can be efficiently controlled with a small current. The pulling force can be changed stably.
  • each of the plurality of first magnetosensitive layers is configured to be magnetized in an anti-parallel direction by a magnetic field.
  • the direction of each magnetic field generated at a predetermined portion as a common portion of each annular magnetic layer when a current flows through each lead wire of a pair of storage elements can be always aligned, so that the magnetic field in the common portion of each annular magnetic layer can be aligned. Can be reliably increased.
  • the intensity of each return magnetic field in each annular magnetic layer can be increased, and as a result, the magnetization reversal of the first magnetosensitive layer can be performed efficiently with a smaller write current.
  • a plurality of conductors are configured to extend in parallel with each other in a region penetrating the annular magnetic layer, so that the plurality of conductors cross each other.
  • the combined magnetic field generated by passing the current through the plurality of conductors can be increased, and as a result, the force S for reversing the magnetization of the first magnetosensitive layer more efficiently can be obtained.
  • the storage layer and the magnetic memory device are mutually interchangeable with the first magnetically sensitive layer.
  • the stacked body is configured to include the second magnetically sensitive layer that can be exchange-coupled magnetically, a material having a high polarizability can be selected as a material for the second magnetically sensitive layer. The rate of change in magnetoresistance of the element can be increased.
  • the nonmagnetic layer, the first magnetic layer laminated on one surface side of the nonmagnetic layer and having a fixed magnetization direction, and the nonmagnetic layer And a second magnetic layer that functions as a second magneto-sensitive layer laminated on the other side of the laminated body, and that the information can be detected based on the current flowing through the laminated body.
  • an insulating layer that can cause a tunnel effect can be used as the nonmagnetic layer.
  • the first magnetic layer is formed using a material having a larger coercive force than the second magnetic layer, the first magnetic layer It is possible to prevent the magnetization direction in the magnetic field from being affected by an unnecessary magnetic field such as an external disturbing magnetic field.
  • FIG. 1 is a block diagram showing an overall configuration of a magnetic memory device M according to an embodiment of the present invention.
  • FIG. 2 is a partial plan view showing a main part configuration of a storage cell group 54 in the magnetic memory device M shown in FIG. 1.
  • FIG. 3 is an essential part perspective view showing the configuration of a storage cell 1 in the magnetic memory device M shown in FIG. 1.
  • FIG. 4 (a)-(c) is a cross-sectional view of the memory cell 1 shown in FIG. 2 along the line VV.
  • FIG. 5 is another partial plan view showing a main configuration of a storage cell group 54 in the magnetic memory device M shown in FIG. 1.
  • FIG. 6 is a cross-sectional view of the memory cell 1 shown in FIG. 5, taken along line WW.
  • FIG. 7 is a circuit diagram of a magnetic memory device M.
  • FIG. 8 is a circuit diagram showing a part of the circuit shown in FIG. 7.
  • FIG. 9 is a magnetic field distribution diagram simulating the magnetic field distribution of the circulating magnetic fields 16 a and 16 b on the XZ plane of the annular magnetic layer 4.
  • FIG. 11 is a cross-sectional view of a conventional magnetic storage cell mainly showing a storage element 120.
  • FIG. 12 is a plan view showing a configuration of a conventional magnetic memory device.
  • the magnetic memory device M includes an address buffer 51, a data buffer 52, a control logic unit 53, a storage cell group 54, a first drive control circuit unit 56, and a second drive control circuit. Part 58 is provided.
  • the address buffer 51 includes an external address input terminal AO—A20, and transfers an address signal fetched from the external address input terminal AO—A20 to the first drive control circuit unit 56 via a Y-direction address line 57.
  • the signal is output to the second drive control circuit 58 via the X-direction address line 55.
  • the data buffer 52 includes an external data terminal DO-D7, an input buffer 52A, and an output buffer 52B.
  • the data buffer 52 is connected to a control port magic unit 53 via a control signal line 53A.
  • the input buffer 52A is connected to the second drive control circuit unit 58 via the X-direction write data bus 60, and is connected to the first drive control circuit unit 56 via the Y-direction write data bus 61. It is connected to the.
  • the output buffer 52B is connected to the first drive control circuit unit 56 via the Y-direction read data bus 62.
  • the input buffer 52A and the output buffer 52B operate according to the control signal input from the control logic unit 53 via the control signal line 53A.
  • the control logic unit 53 has an input terminal CS and an input terminal WE, and controls operations of the data buffer 52, the first drive control circuit unit 56, and the second drive control circuit unit 58.
  • the control logic unit 53 includes an input buffer 52A and an output buffer 52A based on the chip select signal input via the input terminal CS and the write enable signal input via the input terminal WE. Determine which of the 52Bs should be activated and control to activate the input and output buffers 52A and 52B according to this decision. A signal is generated and output to the data buffer 52 via the control signal line 53A.
  • the control logic unit 53 amplifies the chip select signal and the write enable signal to the required voltage levels in the respective drive control circuit units 56 and 58 and outputs the amplified signal.
  • the storage cell group 54 has a matrix structure in which a large number of storage cells 1 as magnetic storage cells are arranged at intersections in the orthogonal word line direction (X direction) and bit line direction (Y direction). .
  • the storage cell 1 is a minimum unit for storing data in the magnetic memory device M, and includes a pair of storage elements (tunnel magnetoresistive elements). The memory cell 1 will be described later in detail.
  • the first drive control circuit section 56 includes a Y-direction address decoder circuit 56A, a sense amplifier circuit 56B, and a Y-direction current drive circuit 56C.
  • the second drive control circuit 58 has an X-direction address decoder circuit 58A, a constant current circuit 58B, and an X-direction current drive circuit 58C.
  • the Y-direction address decoder circuit 56A outputs the bit decode lines 71 (71, 71 ⁇ + 1) based on the address signal input via the Y-direction address line 57. , ⁇ ⁇ ⁇ ).
  • the X-direction address decoder circuit 58 ⁇ based on the address signal input via the X-direction address line 55, has a word decode line 72 (..., 72m, 72m + l,. Select
  • the sense amplifier circuit 56B and the constant current circuit 58B operate during a read operation on the memory cell group 54.
  • the sense amplifier circuit 56B is connected to the memory cell group 54 via each of the read bit lines 13a and 13b, and flows through each of the read bit lines 13a and 13b during a read operation.
  • the information stored in each memory cell 1 is read by detecting each read current.
  • the constant current circuit 58B is connected to the memory cell group 54 via the read switch 83 and the read word line 12 as shown in the figure, and connects the read bit lines 13a and 13b during the read operation.
  • the total current value of the flowing read current (the read current flowing through the memory cell 1) is controlled to be constant.
  • each of the read bit lines 13a and 13b corresponds to a "read line" in the present invention.
  • the Y-direction current drive circuit 56C and the X-direction current drive circuit 58C operate during a write operation on the storage cell group 54.
  • the current drive in the Y direction As shown in FIG. 2, the circuit 56C includes a memory cell group 54 via the write bit line lead-out electrode 42 and each of the write bit lines 5a and 5b (hereinafter also referred to as “write bit line 5” when not distinguished). And supplies a write current to the memory cell group 54 via the write bit lines 5a and 5b during a write operation.
  • X-direction current drive circuit 58C is connected to memory cell group 54 via write word line lead electrode 41 and write word line ("first write line" in the present invention) 6.
  • a write current is supplied to memory cell group 54 via write word line 6 during a write operation.
  • the Y-direction current drive circuit 56C controls each of the write bit lines (the “first” in the present invention) so that the direction of the write current supplied to one side is opposite to the direction of the write current supplied to the other side.
  • Write line 2 Supply write current to 5a and 5b. Further, the write bit line 5a and the write word line 6, and the write bit line 5b and the write word line 6 correspond to “a plurality of conductors” in the present invention.
  • FIG. 2 is a conceptual diagram showing a planar configuration of a main part related to a write operation of the memory cell group 54.
  • the magnetic memory device M includes a plurality of write bit lines 5a and 5b, and a plurality of write word lines 6 respectively intersecting the plurality of write bit lines 5a and 5b.
  • the write bit lines 5a and 5b and the write word line 6 are formed by forming parallel portions 10 extending in parallel with each other in respective regions where they cross each other.
  • each parallel portion 10 is such that the write word line 6 extends in the X direction in a rectangular wave shape (in other words, the portion extending in the + Y direction and the one extending in the Y direction).
  • write bit lines 5a and 5b extend linearly along the Y direction, with the existing portions being formed in a zigzag shape that is alternately repeated via the portions extending in the X direction.
  • Each write bit line 5a, 5b is close to the rectangular wave rising portion (portion extending in the + Y direction) and the falling portion (portion extending in one Y direction) of the write word line 6 They are arranged in a parallel state.
  • write bit line lead-out electrodes 42 are provided at both ends of each of the write bit lines 5a and 5b.
  • One of the write bit line lead electrodes 42 (for example, the upper write bit line lead electrode 42 in the figure) is connected to the Y-direction current drive circuit 56C, The other (for example, the lower write bit line lead-out electrode 42 in the figure) is connected so that it is finally grounded.
  • a write word line lead electrode 41 is provided, and each write word line lead electrode 41 is connected to one (for example, the write word line on the left side in FIG. Line extraction electrode 41) is connected to the X-direction current drive circuit 58C, and the other (for example, the right write word line extraction electrode 41 on the right side in the figure) is finally connected to ground.
  • each memory cell 1 includes annular magnetic layers 4a and 4b (both are also referred to as “annular magnetic layers 4”) and a pair of magnetoresistance effect generators 20a and 20b. I have.
  • Each storage cell 1 includes a parallel portion 10 corresponding to the rising portion of the write word line 6 and a parallel portion 10 corresponding to the falling portion of the write word line 6 adjacent to the parallel portion 10.
  • the write bit lines 5a and 5b and the write word line 6 are provided at respective intersection regions.
  • each memory cell 1 has a parallel portion 10 corresponding to a rising portion of the write word line 6 as a storage element la and a falling portion of the write word line 6.
  • the side of the parallel portion 10 corresponding to is configured as a storage element lb.
  • the annular magnetic layer 4a is oriented in the direction along the lamination surface of the magnetoresistance effect generator 20a (perpendicular to the lamination direction of the magnetoresistance effect generator 20a).
  • the write bit line is formed in an annular shape (for example, a square cylindrical shape) in which the Y direction in FIG. 5a and the write word line 6 penetrate.
  • the entire lower wall of the annular magnetic layer 4a in FIG. 4A constitutes a first magneto-sensitive layer 14a (a portion hatched to the right in FIG. 4A).
  • the write bit line 5a and the write word line 6 are arranged side by side in the Z direction as an example.
  • the annular magnetic layer 4b also has an axial direction (the direction perpendicular to the laminating direction of the magnetoresistive effect expressing body 20b; the Y direction in the figure) along the laminating surface of the magnetoresistive effect realizing body 20b.
  • the axis It is formed in a ring shape (indicated by a symbol G) (for example, a rectangular tube shape) and penetrated by a write bit line 5b and a write word line 6.
  • a symbol G for example, a rectangular tube shape
  • the entire lower wall of the annular magnetic layer 4b in the figure constitutes the first magneto-sensitive layer 14b (the portion hatched to the lower right in the figure).
  • the write bit line 5b and the write word line 6 are arranged side by side in the Z direction.
  • An insulating film is provided between the write bit line 5b and the write word line 6, between the write bit line 5b and the annular magnetic layer 4b, and between the write word line 6 and the annular magnetic layer 4b.
  • each of the annular magnetic layers 4a and 4b is arranged side by side so that the directions of the axes F and G coincide with each other, and each of the write bit lines 5a and the write word lines 6 penetrating each other, and A portion sandwiched between the write bit line 5b and the write word line 6 (hereinafter, also referred to as a "shared portion 34") is configured to share with each other.
  • the annular magnetic layers 4a and 4b are parallel to each other with the directions of the axes F and G coincident with each other, and one side wall of each (in FIG. 4 (a), the annular magnetic layer 4a
  • the right side wall and the left side wall of the annular magnetic layer 4b are arranged side by side in such a manner that they share a predetermined portion (in the present invention). Therefore, the shared portion 34 also functions as the right side wall of the annular magnetic layer 4a and the left side wall of the annular magnetic layer 4b.
  • the first magneto-sensitive layers 14a and 14b are disposed on the same side (the lower side in the figure) with respect to the plane H including the axes F and G (specifically, as shown in FIG.
  • each of the first magneto-sensitive layers 14a and 14b shares one end side (the right end side of the first magneto-sensitive layer 14a and the left end side of the first magneto-sensitive layer 14b), and They are located side by side on the same plane.
  • the magnetoresistive effect expressing body 20a has a first magnetic layer 2a, a tunnel barrier layer (“non-magnetic layer” in the present invention) 3a and a second magnetic layer. 8a (“the second magnetically sensitive layer” in the present invention; hereinafter, also referred to as “the second magnetically sensitive layer 8a”) is laminated in this order on a conductive layer 24a to be described later.
  • the magnetoresistive effect-generating body 20a is located at or near the center of the first magneto-sensitive layer 14a (in the figure, indicated by the symbol J sandwiched between the left side wall 35a of the annular magnetic layer 4a and the shared portion 34).
  • the magnetic layer 8a is provided in a state of being electrically connected to the first magnetically sensitive layer 14a.
  • the magnetoresistive effect-generating body 20a is provided at the center of the first magneto-sensitive layer 14a. With this configuration, the magnetoresistive effect-generating body 20a forms a TMR film S20a (the “laminate” in the present invention) together with the first magneto-sensitive layer 14a. In the TMR film S20a, a current flows in a direction perpendicular to the stacked surface of the magnetoresistance effect generator 20a.
  • the magnetoresistive effect-generating body 20b has a first magnetic layer 2b, a tunnel barrier layer (“non-magnetic layer” in the present invention) 3b,
  • the second magnetic layer 8b (the “second magnetically sensitive layer” in the present invention; hereinafter also referred to as “the second magnetically sensitive layer 8b”) is laminated on the conductive layer 24b described later in this order. ing.
  • the magnetoresistive effect-generating body 20b is located at or near the center of the first magneto-sensitive layer 14b (in the figure, the symbol K sandwiched between the right side wall 35b of the annular magnetic layer 4b and the shared portion 34).
  • the second magneto-sensitive layer 8b is disposed on the surface of the first magneto-sensitive layer 14b so as to be electrically connected to the first magneto-sensitive layer 14b.
  • the magnetoresistance effect-generating body 20b is provided at the center of the first magnetosensitive layer 14b.
  • the magnetoresistive effect-generating body 20b together with the first magneto-sensitive layer 14b, constitutes a TMR film S20b (the “laminate” in the present invention). Also in this TMR film S20b, a current flows in a direction perpendicular to the lamination surface of the magnetoresistance effect expression body 20b.
  • the first magneto-sensitive layer 14a and the second magneto-sensitive layer 8a are magnetically exchange-coupled with each other.
  • the first magnetic layer 14b and the second magnetic layer 8b are magnetically exchange-coupled with each other.
  • the magnetization directions of the first magnetic layers 2a and 2b are fixed in advance in the same direction.
  • the TMR films S20a and S20b are exaggerated relatively larger than other surrounding components in order to explain the film configuration of the TMR films S20a and S20b.
  • the thicknesses of the first magnetosensitive layers 14a and 14b are exaggerated to be relatively thicker than the thicknesses of other surrounding components.
  • the TMR film S20a forms the first magnetic layer 2a and the second magnetic layer 2a when a voltage perpendicular to the lamination surface is applied between the first magnetic layer 2a and the second magnetically sensitive layer 8a.
  • One of the magnetic layers 8a penetrates through the tunnel barrier layer 3a and moves to the other of the first magnetic layer 2a and the second magnetosensitive layer 8a, so that a tunnel current flows. It is configured to be able to improve memory speed and access speed.
  • This tunnel current is applied to the tunnel barrier layer It changes depending on the relative angle between the spin of the first magnetic layer 2a and the spin of the second magnetically sensitive layer 8a at the interface with 3a.
  • the magnetoresistance change ratio (MR ratio) is defined as the following equation.
  • dR means a difference in resistance between when the spins are parallel to each other and when it is antiparallel
  • R means a resistance when the spins are parallel to each other.
  • tunnel resistance Rt the resistance value to the tunnel current (hereinafter also referred to as "tunnel resistance Rt") strongly depends on the film thickness T of the tunnel barrier layers 3a and 3b. Specifically, the tunnel resistance Rt increases exponentially with respect to the film thickness T of the tunnel barrier layers 3a and 3b in the low voltage region, as shown in the following equation.
  • ⁇ is the barrier height
  • m * is the effective mass of electrons
  • Ef is Fermi energy
  • h Planck's constant.
  • a tunnel resistance Rt of about several tens of Q ⁇ (/ m) 2 is appropriate in order to achieve matching with a semiconductor device such as a transistor.
  • the tunnel resistance Rt should be l Ok Q Q (/ im) 2 or less, more preferably lk Q ⁇ m) 2 or less. Is preferred. Therefore, in order to realize the above-mentioned tunnel resistance Rt, it is desirable that the thickness T of the tunnel barrier layers 3a and 3b be 2 nm or less, more preferably 1.5 nm or less.
  • the tunnel resistance Rt can be reduced.
  • the MR ratio may decrease due to the leakage current caused by the unevenness of the junction interface with the magnetic layers 8a and 8b.
  • the thickness T of each of the tunnel barrier layers 3a and 3b needs to be set to a thickness that does not allow leakage current to flow, and specifically, it is preferable to set it to 0.3 nm or more. .
  • the first magnetic it is preferable that the coercive force of the conductive layers 2a and 2b be larger than the coercive force of the second magnetosensitive layers 8a and 8b.
  • the first magnetic layer 2a, 2b coercivity of, (50/4 ⁇ ) X 10 3 It is desirable tool especially greater than A / m (100/4 ⁇ ) X 10 3 A / m or more is desirable. With this configuration, it is possible to prevent the magnetization directions in the first magnetic layers 2a and 2b from being affected by an unnecessary magnetic field such as an external magnetic field.
  • the first magnetic layers 2a and 2b are made of, for example, a 5 nm thick cobalt iron alloy (CoFe).
  • the first magnetic layers 2a and 2b can be composed of a simple substance of cobalt (Co), a cobalt platinum alloy (CoPt), a nickel iron cobalt alloy (NiFeCo), or the like.
  • the second magnetosensitive layers 8a and 8b are made of, for example, a single element of cobalt (Co), a cobalt iron alloy (CoFe), a cobalt platinum alloy (CoPt), a nickel iron alloy (NiFe), or a nickel iron cobalt alloy (NiFeCo). Can be configured.
  • the easy axis of magnetization of the first magnetic layers 2a and 2b and the second magnetic sensitive layers 8a and 8b is determined by the magnetization directions of the first magnetic layers 2a and 2b and the second magnetic sensitive layers 8a and 8b. Are desirably parallel to each other in order to stabilize them in a state of being parallel or antiparallel to each other.
  • the annular magnetic layer 4 due to the above-described configuration, a write current flowing through the parallel portion 10 in the write bit line 5 and the write word line 6 generates a return magnetic field therein. This return magnetic field reverses according to the direction of the current flowing through write bit line 5 and write word line 6.
  • the annular magnetic layer 4 also becomes, for example, a nickel iron alloy (NiFe) force, and the first magnetically sensitive layer 14a, 14b has a first coercive force (100 / 4 ⁇ ) ⁇ 10 3 A / m or less. It is desirable that the magnetic layers 2a and 2b be configured to have a coercive force smaller than that of the magnetic layers 2a and 2b.
  • the permeability of the annular magnetic layer 4 is larger.
  • the force is preferably 2000 or more, more preferably 6000 or more.
  • the thickness of the first magnetosensitive layers 14a and 14b is preferably in the range of 0.5 nm or more and 40 nm or less. More preferably, it is set within the range of 0.5 nm or more and 30 nm or less. By defining (setting) the film thickness of the first free layer 14a, 14b within this range, the magnetization direction of the first free layer 14a, 14b and the second free layer 8a, 8b can be changed.
  • the total value of the write currents flowing through the write word line 6 and the write bit line 5a penetrating the circular magnetic layer 4a (total value of the write current flowing through the storage element la) and the circular A force that balances the total value of the write currents flowing through the write word line 6 and the write bit line 5b penetrating the magnetic layer 4b (total value of the write currents flowing through the storage element lb side).
  • the write current of the entire memory cell 1 can be reduced.
  • the write bit line 5 and the write word line 6 are formed by sequentially stacking 10 nm thick titanium (Ti), lOnm thick titanium nitride (TiN), and 500 nm thick aluminum (A1). It is configured.
  • FIG. 3 a configuration related to the information reading operation will be described with reference to FIGS. 3, 5, and 6.
  • each storage cell 1 is disposed at each intersection of a plurality of read word lines 12 and a plurality of read bit lines 13a and 13b.
  • each storage element la, lb in the storage cell 1 has a base on which a pair of Schottky diodes 75a, 75b (hereinafter, also simply referred to as “diodes 75a, 75b”) is formed.
  • a pair of magnetoresistive effect generators 20a and 20b and a ring-shaped magnetic layer 4 (4a and 4b) are stacked in this order on 11.
  • each memory cell 1 (la, lb) (on which the magnetoresistive effect bodies 20a, 20b are formed) is connected to the read bit lines 13a, 13b via the diodes 75a, 75b and the connection layers 13T, 13T. 13b.
  • the upper surfaces of the storage elements la and lb (opposite to the magnetoresistive elements 20a and 20b) are connected to the read word lines 12.
  • each read bit line 13a, 13b supplies a read current to each of a pair of storage elements la, lb in each storage cell 1, and as shown in FIG. Line extraction electrodes 44 are provided respectively.
  • the read word line 12 guides a read current flowing through each of the storage elements la and lb to ground (earth potential), and read word line lead electrodes 43 are provided at both ends thereof. .
  • the diode 75a is composed of a substrate 26 and an epitaxy laminated on the substrate 26. And a conductive layer 24a laminated on the epitaxial layer 25, and a Schottky barrier is formed between the conductive layer 24a and the epitaxial layer 25.
  • the diode 75b includes a substrate 26, an epitaxial layer 25 laminated on the substrate 26, and a conductive layer 24b laminated on the epitaxial layer 25, as shown in FIG. A Schottky barrier is formed between 24b and the epitaxial layer 25.
  • the diode 75a and the diode 75b are electrically connected to each other via the magnetoresistance effect generators 20a and 20b and the annular magnetic layer 4, and are electrically insulated from each other except for these portions. Have been. Note that, in the figure, each part indicated by reference numerals 11A, 17A, and 17B is formed of an insulating layer.
  • the storage cell 1 for each bit string of the storage cell group 54 and a part of the readout circuit including the sense amplifier circuit 56B are a unit of the readout circuit. , 80 ⁇ , 80 ⁇ + 1,..., And the unit read circuits 80 are arranged in parallel in the bit string direction.
  • Each unit readout circuit 80 is connected to the ⁇ direction address decoder circuit 56 ⁇ ⁇ ⁇ via a bit decode line 71 ( ⁇ 71 ⁇ , 71 ⁇ + 1, ⁇ ), and via a ⁇ direction read data bus 62. Connected to the output buffer 52 ⁇ .
  • Each of the storage elements la and lb of each of the storage cells 1 included in each of the unit read circuits 80 has one end connected to each of the unit read circuits 80 via a pair of diodes 75a and 75b. They are connected to bit lines 13a and 13b, respectively.
  • each of the storage elements la and lb of each of the storage cells 1 included in each of the unit read circuits 80 has the other end thereof connected to each of the read word lines 12 (..., 12m, 12m + l,. ).
  • each read word line 12 is connected to each read switch 83 ( ⁇ , 83m, 83m + l, ⁇ ) via the read word line lead electrode 43 (see FIG. 5).
  • each readout switch 83 is connected to a common constant current circuit 58B.
  • Each read switch 83 is connected to an X-direction address decoder circuit 58A via a word decode line 72 (..., 72m, 72m + l,). Selection from 58A It is configured to conduct when a selection signal is input.
  • each of the read bit lines 13a and 13b is connected to the sense amplifier circuit 56B via the read bit line lead electrode 44 (see FIG. 5), and the other ends are finally connected to the sense amplifier circuit 56B. Grounded.
  • the sense amplifier circuit 56B is stored in the memory cell 1 where the read current has flowed in each unit read circuit 80, based on the difference between the read currents flowing through the pair of read bit lines 13a and 13b in each unit read circuit 80. Function to detect the current information (binary information) and output the detected information to the directional reading data bus 62 via the output line 82 ( ⁇ , 82 ⁇ , 82 ⁇ + 1, ⁇ ). It has.
  • the writing direction is such that the direction of the current at the portion of the write word line 6 passing through the storage element la is from the near side to the far side (in the + Y direction) of the drawing.
  • each write bit line 5a, 5b is written so that the current direction of the write word line 6 matches the current direction of the write word line 6.
  • a write current is applied to bit lines 5a and 5b.
  • a write current is applied to the write bit line 5a so as to force the write bit line 5a from the near side to the far side (in the + Y direction) of the drawing, and the write bit line 5b , A write current is passed from the back side of the paper to the front side (in the Y direction).
  • a clockwise return magnetic field 16a is generated inside the annular magnetic layer 4a.
  • a return magnetic field 16b in the counterclockwise direction is generated inside the annular magnetic layer 4b.
  • the magnetization directions of the first magneto-sensitive layer 14a and the second magneto-sensitive layer 8a are in the X direction
  • the first magneto-sensitive layer 14b and the second The magnetization direction of the magnetosensitive layer 8b is the + X direction. That is, the magneto-sensitive layers of the storage elements la and lb (the first magneto-sensitive layer 14a and the second magneto-sensitive layer 8a, the first magneto-sensitive layer 14b, and the second magneto-sensitive layer 8b) are antiparallel to each other. Magnetized.
  • the direction of each of the circulating magnetic fields 16a and 16b matches.
  • the magnetization direction of the second magneto-sensitive layer 8a and the magnetization direction of the first magnetic layer 2a match (become parallel to).
  • the magnetization direction of the second magnetosensitive layer 8b and the first The magnetization direction of the magnetic layer 2b is opposite (antiparallel).
  • information for example, “0” is stored in the storage cell 1.
  • the current is supplied to the write word line 6 and each of the write bit lines 5a, 5b in the opposite direction to that in FIG.
  • a return magnetic field 16a in the counterclockwise direction is generated inside the annular magnetic layer 4a.
  • a return magnetic field 16b in the clockwise direction is generated inside the annular magnetic layer 4b.
  • the magneto-sensitive layers of the storage elements la and lb are magnetized in directions antiparallel to each other.
  • the direction of each of the circulating magnetic fields 16a and 16b (the direction opposite to that in FIG. 13B) is the same at the shared portion 34 of each of the annular magnetic layers 4a and 4b. Therefore, as shown in the figure, in the memory element la, the magnetization direction of the second magneto-sensitive layer 8a and the magnetization direction of the first magnetic layer 2a are opposite (anti-parallel) to each other.
  • the magnetization direction of the second magnetically sensitive layer 8b and the magnetization direction of the first magnetic layer 2b match (become parallel to). As a result, information (for example, “1”) is stored in the storage cell 1.
  • the storage elements la and lb if the magnetization directions of the first magnetic layers 2a and 2b and the second magneto-sensitive layers 8a and 8b are parallel, a low resistance state in which a large tunnel current flows, If it is antiparallel, it will be in a high resistance state where only a small tunnel current flows. That is, the storage element la and the storage element lb forming a pair always store blue information when one of them has low resistance and the other has high resistance.
  • each second magnetosensitive layer 8a , 8b are not reversed, and the data is not rewritten.
  • FIG. 9 shows the distribution in a plane parallel to the XZ plane.
  • FIG. 10 shows the magnetic field distribution of each of the circulating magnetic fields 16a and 16b in a plane parallel to the XY plane.
  • each of the return magnetic fields 16a and 16b are represented by the length and direction of the arrow. According to these figures, it is possible to confirm that the respective circulating magnetic fields 16a and 16b circulate in the respective annular magnetic layers 4a and 4b by changing the strength and direction thereof in various ways.
  • each of the circulating magnetic fields 16a and 16b is a plane parallel to the XZ plane. It is confirmed that the direction and the strength are the same in both directions and in the plane parallel to the XY plane, and that the strength is higher than other parts.
  • the directions and the strengths of the respective recirculating magnetic fields 16a, 16b are extremely stable at the center of each of the first magnetosensitive layers 14a, 14b. Therefore, in the memory cell 1 in which the magnetoresistive effect elements 20a and 20b are arranged at the center of each of the first magnetosensitive layers 14a and 14b, the magnetosensitive layer of the storage element la (the first magnetosensitive layer 14a and 14b) is provided. And the magnetization directions of the magnetic sensing layers of the storage element lb (the first sensing layer 14b and the second sensing layer 8b) are parallel to the X-axis direction.
  • the magnetization direction of the magneto-sensitive layer of the storage element la and the magnetization direction of the magneto-sensitive layer of the storage element lb can be reliably changed in efficiency.
  • the magnetoresistive elements 20a and 20b are disposed in the center of each of the first magnetosensitive layers 14a and 14b.
  • the directions and the strengths of the respective circulating magnetic fields 16a and 16b are almost the same, so that the respective magnetoresistance effect generators 20a and 20b are disposed near the center.
  • each magnetic layer (the first magnetic layer 14a and the second magnetic layer 8a, the first magnetic layer 14b, and the second magnetic layer) of each of the storage elements la and lb can be used.
  • the magnetization direction of the magnetic layer 8b) is efficiently changed, and the force can be surely changed.
  • a Y-direction address decoder circuit 56A to which an address signal is input via the address buffer 51 selects one of the plurality of bit decode lines 71 based on the address signal, and a corresponding sense amplifier. Outputs control signal to circuit 56B.
  • the sense amplifier circuit 56B that has received the control signal applies a voltage to the connected read bit lines 13a and 13b. As a result, a positive potential is applied to the sides of the TMR films S20a and S20b in the storage elements la and lb.
  • the X-direction address decoder circuit 58A which receives the address signal via the address buffer 51, receives a plurality of word decodes based on the address signal.
  • the corresponding read switch 83 is driven to be turned on (conductive state).
  • a read current flows through storage cell 1 arranged at the intersection of selected bit decode line 71 (that is, read bit line 13a, 13b) and word decode line 72 (that is, read word line 12).
  • bit decode line 71 that is, read bit line 13a, 13b
  • word decode line 72 that is, read word line 12.
  • each of the storage elements la and lb in the storage cell 1 one is maintained in a low resistance state and the other is maintained in a high resistance state in accordance with the value of the stored information, and the read current flowing through the storage cell 1 is maintained.
  • the total current is maintained at a constant value by the constant current circuit 58B.
  • the read current flowing through one of the storage elements la and lb is large, and the read current flowing through the other is small.
  • the respective magnetization directions of the first magnetic layer 2a and the second magneto-sensitive layer 8a are parallel in the storage element la, and the first magnetization direction in the storage element lb. Since the magnetization directions of the magnetic layer 2b and the second magnetosensitive layer 8b are antiparallel, the storage element la is in a low resistance state and the storage element lb is in a high resistance state.
  • the respective magnetization directions of the first magnetic layer 2a and the second magnetosensitive layer 8a in each of the storage elements la and lb are the same.
  • the storage element la is in a high resistance state and the storage element lb is in a low resistance state.
  • the sense amplifier circuit 56B acquires the information (binary information) stored in the storage cell 1 by detecting the difference in the amount of current generated between the storage elements la and lb.
  • the sense amplifier circuit 56B outputs the acquired information to the external data terminals D0 to D7 via the output buffer 52B. Thus, the reading of the binary information stored in the storage cell 1 is completed.
  • the plurality of write bit lines 5a and 5b and the plurality of write bits extending so as to intersect with these write bit lines 5a and 5b, respectively.
  • the storage elements la and lb having the above-described configuration include the TMR films S20a and S20b having the word lines 6 and having the above-described configuration, and the write bit lines 5a and 5b and the annular magnetic layer 4 surrounding the write word line 6. With this arrangement, a combined magnetic field generated by flowing a current through the write bit line 5a and the write word line 6, and the write bit line 5b and the write word line 6 is generated by the write bit lines 5a, 5b and 5b.
  • the size can be increased as compared with the configuration in which the write word lines 6 intersect, and the current flowing through both the write bit lines 5a, 5b and the write word line 6 causes the write bit lines 5a, 5b, Since the magnetic flux generated around the write word line 6 can be confined in the closed magnetic path composed of the annular magnetic layers 4a and 4b, the generation of the leakage magnetic flux can be reduced, and as a result, the magnetic flux generated in the adjacent storage cell can be reduced. The adverse effects can be significantly reduced. In addition, as the leakage magnetic flux decreases, the strength of the magnetic field in each of the first magneto-sensitive layers 14a and 14b formed on a part of each of the annular magnetic layers 4a and 4b increases.
  • the magnetization reversal of the free magnetic layers 14a and 14b and the second free magnetic layers 8a and 8b can be performed. Furthermore, a pair of storage elements la and lb in one storage cell 1 are configured to share a part of the annular magnetic layer 4 (the shared portion 34) with each other, so that the annular magnetic layers 4a and 4b are provided separately.
  • the magnetic flux density in the shared portion 34 of each of the annular magnetic layers 4a and 4b can be increased, and as a result, the strength of each of the return magnetic fields 16a and 16b in each of the annular magnetic layers 4a and 4b, and The strength of the magnetic field in each of the first magneto-sensitive layers 14a, 14b formed in a part of each of the annular magnetic layers 4a, 4b can be further enhanced. Therefore, the magnetization reversal of the first magneto-sensitive layers 14a and 14b and the second magneto-sensitive layers 8a and 8b can be performed with a smaller write current, together with the reduction of the generation of the leakage magnetic flux. You.
  • the direction and intensity of the circulating magnetic fields 16a, 16b are uniform, and the intensity thereof is larger than that of the other portions, or at or near the center of each first magnetosensitive layer 14a, 14b (FIG. 9).
  • the magnetoresistive effect generators 20a and 20b in the range indicated by reference symbols J and K in FIGS. 10 and 10, the magneto-sensitive layer (the first magneto-sensitive layer 14a and the second The magnetization direction of the magneto-sensitive layer 8a) and the magnetization direction of the magneto-sensitive layer (the first magneto-sensitive layer 14b and the second magneto-sensitive layer 8b) of the storage element lb can be reliably set to desired directions. As a result, information can be reliably stored.
  • Each magnetic layer (the first magnetic layer 14a and the first magnetic layer 14a and 5b) is magnetized in a direction antiparallel to each other by a magnetic field generated around the write bit lines 5a and 5b and the write word line 6.
  • the write bit lines 5a, 5b and the write Since the direction of the return magnetic fields 16a, 16b generated in the common part 34 of the annular magnetic layers 4a, 4b when a current flows through the common word line 6 can always be aligned, the common part of the annular magnetic layers 4a, 4b
  • the magnetic flux density in 34 can be reliably increased.
  • each reflux in each of the annular magnetic layers 4a and 4b As a result of the strength of the magnetic fields 16a and 16b being increased, the magnetization reversal of the magnetosensitive layer can be efficiently performed with a smaller write current.
  • first magnetic layer 14a and the second magnetic layer 8a which are formed so as to be magnetically exchange-coupled to each other
  • first magnetic layer 14b and the second magnetic layer 8b The first magnetic layer 14a, 14b is composed of a part of each of the annular magnetic layers 4a, 4b, and the second magnetic layer, which constitutes each magnetic layer, is formed. Since a material having high polarizability can be selected as a material for the magnetosensitive layers 8a and 8b, the magnetoresistance change rate of the storage elements la and lb can be increased.
  • the present invention is not limited to the above embodiment.
  • the storage cell 1 having a configuration including each of the first magnetically sensitive layers 14a and 14b of the annular magnetic layer 4 and each of the second magnetically sensitive layers 8a and 8b is exemplified.
  • the memory cell having a configuration in which only the first magnetically sensitive layers 14a and 14b of the annular magnetic layer 4 are provided as the magnetically sensitive layers, omitting the second magnetically sensitive layers 8a and 8b You can also.
  • a non-magnetic conductive layer between each first free layer 14a, 14b of the annular magnetic layer 4 and each second free layer 8a, 8b, each first free layer is provided.
  • a storage cell in which the second magnetosensitive layers 8a and 8b are antiferromagnetically coupled to the second magnetosensitive layers 8a and 8b can also be configured. Further, in the embodiment of the present invention, the description has been made of an example in which the present invention is applied to a memory cell in which the TMR films S20a and S20b are configured to have a coercive force difference type structure. It goes without saying that the present invention can be applied to the configured memory cell.
  • one-bit information can be stored by having a pair of annular magnetic layers 4a and 4b and sharing a part of each of the pair of annular magnetic layers 4a and 4b.
  • the storage cell 1 for storing is described as an example, for example, a storage element having one magnetoresistive effect generator 20a in FIG. 4 and one annular magnetic layer 4a in FIG. 4 (for example, the storage element in FIG. 4)
  • the present invention can be applied to a storage cell having the element la) and storing one bit of information by one annular magnetic layer 4a and one magnetoresistive effect generator 20a.
  • the magnetoresistive effect-generating body 20a is provided at or near the center of the first magnetosensitive layer 14a.
  • the above-described storage cell 1 has the same structure as the storage element la (or storage element lb).
  • One or more storage elements are arranged in a row on the left side wall 35a of the annular magnetic layer 4a in the storage element la or on the right side wall 35b side of the annular magnetic layer 4b in the storage element 1b, with their axes aligned.
  • the present invention can be applied to a storage cell configured to store 1-bit information by three or more storage elements.
  • the magnetoresistive effect-generating body 20a is provided at or near the center of each of the first magnetosensitive layers 14a and 14b.
  • the annular magnetic layer penetrated by the plurality of conductors that generate the magnetic field, and the magnetic field in the annular magnetic layer whose magnetization direction changes due to the magnetic field.
  • the leakage magnetic flux is reduced, the strength of the magnetic field in the first magneto-sensitive layer formed in a part of the annular magnetic layer is increased. As a result, the magnetization reversal of the first magneto-sensitive layer is performed with a smaller write current. It can be carried out. Further, by arranging the magnetoresistive effect generator at or near the center of the first magnetosensitive layer that can be magnetized with almost the same direction and intensity, the magnetization direction of the first magnetosensitive layer can be changed to a desired direction. Can be set reliably. As a result, a storage cell and a magnetic memory device capable of reliably storing information can be realized while the generation of leakage magnetic flux is reduced by the annular magnetic layer and the adverse effect on adjacent storage cells is significantly reduced.

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Abstract

L'invention concerne une cellule de mémoire magnétique capable, d'une part, d'éviter la production d'un flux magnétique de fuite grâce à l'utilisation d'une couche magnétique annulaire et, d'autre part, de stocker de façon sûre les informations. Cette cellule de mémoire magnétique comporte : des couches magnétiques annulaires (4a, 4b) traversées par des lignes de bit d'écriture (5a, 5b) et des lignes de mot d'écriture (6) produisant un champ magnétique ; et des pellicules TMR (S20a, S20b) constituées, d'une part, de premières couches magnéto-sensibles (14a, 14b) dont la direction de magnétisation peut être modifiée par un champ magnétique dans les couches magnétiques annulaires (4a, 4b) et, d'autre part, d'éléments magnéto-résistants (20a, 20b) disposés sur la surfaces des premières couches magnéto-sensibles (14a, 14b) de façon que le courant circule dans une direction verticale au plan de lamination. Les éléments magnéto-résistants (20a, 20b) sont disposés au centre ou au voisinage du centre des premières couches magnéto-sensibles (14a, 14b).
PCT/JP2004/011830 2003-08-21 2004-08-18 Cellule de memoire magnetique et dispositif a memoire magnetique Ceased WO2005020326A1 (fr)

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