Magnetic Recording Array, Neuromorphic Device, and Control Method of Magnetic Recording Array

Abstract

The magnetic recording array (200) of the present embodiment includes a plurality of spin elements (100), a first reference element (101), and a second reference element (102). The plurality of spin elements, the first reference element, and the second reference element each have wirings (20-24) and a laminate (10) including a first ferromagnetic layer (1) laminated on the wirings. The resistance of the wirings (21, 23) of the first reference element is higher than the resistance of the wirings (20) of the respective spin elements. The resistance of the wirings of the second reference element is higher than the resistance of the wirings of the respective spin elements. The resistance of the wirings (22, 24) of the second reference element is lower than the resistance of the wirings of the respective spin elements.

Description

Technical Field

[0001] The present invention relates to a magnetic recording array, a neuromorphic device, and a control method for a magnetic recording array. Background Art

[0002] A new generation of non-volatile memories that replace flash memories and the like, where miniaturization has reached its limit, has attracted much attention. For example, MRAM (Magnetoresistive Random Access Memory), ReRAM (Resistance Random Access Memory), PCRAM (Phase Change Random Access Memory), etc. are known as new generation non-volatile memories.

[0003] MRAM is a magnetoresistive element that uses a magnetoresistive effect element. The resistance value of the magnetoresistive effect element varies according to the relative angle of magnetization directions of two magnetic films. MRAM records the resistance value of the magnetoresistive effect element as data.

[0004] Even among spin elements that utilize magnetoresistance changes, spin-orbit torque type magnetoresistive effect elements that utilize spin-orbit torque (SOT) (for example, Patent Document 1), or magnetic domain wall movement type magnetic recording elements that utilize the movement of magnetic domain walls (for example, Patent Document 2) have also attracted much attention.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-216286

[0008] Patent Document 2: Japanese Patent No. 5441005 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] Spin elements record data, for example, by resistance values. The resistance value of a spin element varies according to temperature and degradation. When the resistance value of a spin element drifts, the reference point that is the threshold for recording data changes, and the reliability of the data decreases.

[0011] In addition, spin elements are often integrated and used as a magnetic recording array. It is difficult to check each of many spin elements during use, and it is impossible to correctly judge a failure.

[0012] The present invention has been developed in view of the above problems, and an object thereof is to provide a magnetic recording array, a neuromorphic device, and a control method for a magnetic recording array with high data reliability.

[0013] Technical solutions for solving problems

[0014] (1) A first method provides a magnetic recording array having: a plurality of spin elements, a first reference element, and a second reference element. The plurality of spin elements, the first reference element, and the second reference element each have a wiring and a laminate including a first ferromagnetic layer laminated on the wiring. The resistance of the wiring of the first reference element is higher than the resistance of the wiring of each spin element, and the resistance of the wiring of the second reference element is lower than the resistance of the wiring of each spin element.

[0015] (2) In the magnetic recording array of the above method, it may also be that the width of the wiring of the first reference element is narrower than the width of the wiring of the spin element, and the width of the wiring of the second reference element is wider than the width of the wiring of the spin element.

[0016] (3) In the magnetic recording array of the above method, it may also be that the thickness of the wiring of the first reference element is thinner than the thickness of the wiring of the spin element, and the thickness of the wiring of the second reference element is thicker than the thickness of the wiring of the spin element.

[0017] (3) In the magnetic recording array of the above method, it may also be that the wirings of the spin element, the first reference element, and the second reference element are each made of the same material.

[0018] (4) In the magnetic recording array of the above method, it may also be that the resistance of the wiring of the first reference element is 105% or more of the resistance of the wiring of the spin element, and the resistance of the wiring of the second reference element is 95% or less of the resistance of the wiring of the spin element.

[0019] (5) In the magnetic recording array of the above method, it may also be that there is a power supply that generates a potential difference along the length direction of the wirings of the plurality of spin elements, the first reference element, and the second reference element, and the power supply applies the same voltage to the wirings of the plurality of spin elements, the first reference element, and the second reference element.

[0020] (6) In the magnetic recording array of the above method, it may also be that the laminate has, from the side close to the wiring, the first ferromagnetic layer, a non-magnetic layer, and a second ferromagnetic layer, and the wiring is any one of a metal, an alloy, an intermetallic compound, a metal boride, a metal carbide, a metal silicide, and a metal phosphide having a function of generating a spin current due to the spin Hall effect when current flows.

[0021] (7) In the magnetic recording array of the above method, it may also be that the laminate has, from the side close to the wiring, a non-magnetic layer and the first ferromagnetic layer, and the wiring is a ferromagnetic layer capable of having magnetic domain walls inside.

[0022] (8) The second mode provides a neuromorphic device having the magnetic recording array of the mode.

[0023] (9) The third mode provides a method for controlling a magnetic recording array, which is a method for controlling the magnetic recording array of the mode, and includes: a step of applying the same write voltage to the wirings of the write target spin element, the first reference element, and the second reference element among the plurality of spin elements; a step of applying a read voltage in the stacking direction of the elements to which the write voltage is applied; and a step of comparing the resistance of the spin element with the resistances of the first reference element and the second reference element.

[0024] (10) In the method for controlling the magnetic recording array of the mode, it may also be that when comparing the resistance of the spin element with the resistances of the first reference element and the second reference element, writing to the spin element is prohibited when the resistance of the spin element is not between the resistance of the first reference element and the resistance of the second reference element.

[0025] (11) In the method for controlling the magnetic recording array of the mode, it may also be that when comparing the resistance of the spin element with the resistances of the first reference element and the second reference element, when the resistance of the spin element is not between the resistance of the first reference element and the resistance of the second reference element, writing and reading of data to and from the spin element are replaced with other elements.

[0026] Advantages of the Invention

[0027] The data of the magnetic recording array, neuromorphic device, and method for controlling the magnetic recording array of the mode have high reliability. Description of the Drawings

[0028] Figure 1 is a schematic diagram of the magnetic recording array of the first embodiment.

[0029] Figure 2 is a cross-sectional view of a characteristic part of the magnetic recording array of the first embodiment.

[0030] Figure 3 is a cross-sectional view of the spin element of the first embodiment.

[0031] Figure 4 is a top view of the spin element of the first embodiment.

[0032] Figure 5 is a top view of the first reference element of the first embodiment.

[0033] Figure 6 is a top view of the second reference element of the first embodiment.

[0034] Figure 7 It is a flowchart of an example of the operation of the magnetic recording array of the first embodiment.

[0035] Figure 8 It is a cross-sectional view of the first reference element of the first modification.

[0036] Figure 9 It is a cross-sectional view of the second reference element of the first modification.

[0037] Figure 10 It is a cross-sectional view of the spin element of the second embodiment.

[0038] Figure 11 It is a cross-sectional view of the spin element of the third embodiment. Detailed Embodiment

[0039] Hereinafter, the present embodiment will be described in detail with appropriate reference to the drawings. In the drawings used in the following description, for the sake of easy understanding of the features, the portions that become the features are sometimes enlarged for convenience, and the dimensional ratios of the respective structural elements are sometimes different from the actual ones. The materials, dimensions, etc. exemplified in the following description are just examples, and the present invention is not limited to these, and appropriate changes can be made within the range of achieving the effects of the present invention.

[0040] First, the directions are defined. One direction on one surface of the substrate Sub (refer to Figure 2 ) to be described later is set as the x direction, and the direction orthogonal to the x direction is set as the y direction. The x direction is the direction in which the wirings to be described later extend, and is the length direction of the wirings. The z direction is the direction orthogonal to the x direction and the y direction. The z direction is an example of the stacking direction. Hereinafter, the +z direction is sometimes expressed as "up" and the -z direction is sometimes expressed as "down". The up and down do not necessarily coincide with the direction of gravity application.

[0041] "First Embodiment"

[0042] Figure 1 It is a structural diagram of the magnetic recording array 200 of the first embodiment. The magnetic recording array 200 includes: a plurality of magnetoresistive elements 100, a plurality of first reference elements 101, a plurality of second reference elements 102, a plurality of write wirings Wp1 to Wpn, a plurality of common wirings Cm1 to Cmn, a plurality of read wirings Rp1 to Rpn, a plurality of first switch elements SW1, a plurality of second switch elements SW2, and a plurality of third switch elements SW3. The magnetic recording array 200 can be used for, for example, a magnetic memory or the like. The magnetoresistive element 100 is an example of a spin element.

[0043] The magnetoresistive effect element 100, the first reference element 101, and the second reference element 102 are arranged, for example, in a row and column pattern. The first reference element 101 and the second reference element 102 are respectively connected to the write wirings Wp1 to Wpn, for example. The number of the first reference element 101 and the second reference element 102 is not limited to this case, as long as there is at least one of each in one magnetic recording array 200.

[0044] The write wirings Wp1 to Wpn are wirings for writing data. The write wirings Wp1 to Wpn are respectively connected to a plurality of magnetoresistive effect elements 100, the first reference element 101, and the second reference element 102, for example. The write wirings Wp1 to Wpn are connected to a power supply (not shown).

[0045] The common wirings Cm1 to Cmn are wirings used for both writing and reading data. The common wirings Cm1 to Cmn electrically connect the magnetoresistive effect element 100, the first reference element 101, or the second reference element 102 at a reference potential, for example. The reference potential is, for example, ground. The common wirings Cm1 to Cmn can be provided on each of the magnetoresistive effect element 100, the first reference element 101, or the second reference element 102, or can be provided across a plurality of elements.

[0046] The read wirings Rp1 to Rpn are wirings used for reading data. The read wirings Rp1 to Rpn are respectively connected to a plurality of magnetoresistive effect elements 100, the first reference element 101, and the second reference element 102, for example. The read wirings Rp1 to Rpn are connected to a power supply (not shown).

[0047] The first switching element SW1, the second switching element SW2, and the third switching element SW3 are respectively connected to the magnetoresistive effect element 100, the first reference element 101, and the second reference element 102, for example. The first switching element SW1 is located between the write wirings Wp1 to Wpn and the magnetoresistive effect element 100, the first reference element 101, or the second reference element 102. The second switching element SW2 is located between the common wirings Cm1 to Cmn and the magnetoresistive effect element 100, the first reference element 101, or the second reference element 102. The third switching element SW3 is located between the read wirings Rp1 to Rpn and the magnetoresistive effect element 100, the first reference element 101, or the second reference element 102.

[0048] When the first switching element SW1 and the second switching element SW2 are set to ON, a write current flows between the write wirings Wp1 to Wpn and the common wirings Cm1 to Cmn connected to the specified magnetoresistive element 100, the first reference element 101, and the second reference element 102. When the second switching element SW2 and the third switching element SW3 are set to ON, a read current flows between the common wirings Cm1 to Cmn and the read wirings Rp1 to Rpn connected to the specified magnetoresistive element 100, the first reference element 101, and the second reference element 102.

[0049] The first switching element SW1, the second switching element SW2, and the third switching element SW3 are elements that control the flow of current. The first switching element SW1, the second switching element SW2, and the third switching element SW3 are, for example, elements that utilize a phase change of a crystal layer such as a transistor or an Ovonic Threshold Switch (OTS), elements that utilize a change in band structure such as a Metal-Insulator Transition (MIT) switch, elements that utilize a breakdown voltage such as a Zener diode and an avalanche diode, and elements whose conductivity changes with a change in atomic position.

[0050] The first switching element SW1, the second switching element SW2, and the third switching element SW3 are all elements connected to the same wiring and can also be shared. For example, in the case of jointly owning the first switching element SW1, one first switching element SW1 is provided upstream of the write wirings Wp1 to Wpn. For example, in the case of jointly owning the second switching element SW2, one second switching element SW2 is provided upstream of the common wirings Cm1 to Cmn. For example, in the case of jointly owning the third switching element SW3, one third switching element SW3 is provided upstream of the read wirings Rp1 to Rpn.

[0051] Figure 2 It is a cross-sectional view of the main part of the magnetic recording array 200 of the first embodiment. Figure 2 It is a cross-section obtained by cutting the magnetoresistive element 100 along the xz plane passing through the center of the width in the y direction of the wiring 20 described below.

[0052] Figure 2 The first switching element SW1 and the second switching element SW2 shown are transistors Tr. The third switching element SW3 is electrically connected to the electrode E and is located, for example, Figure 2 in the y direction. The transistor Tr is, for example, a field effect transistor and has a gate electrode G and a source S and a drain S formed on a gate insulating film GI and a substrate Sub. The substrate Sub is, for example, a semiconductor substrate.

[0053] The transistor Tr and the magnetoresistive element 100 are electrically connected via the conductive portions 31, 32, and the via wiring Via. In addition, the transistor Tr and the write wiring Wp or the common wiring Cm are connected by the via wiring Via. The via wiring Via extends, for example, in the z direction.

[0054] The periphery of the magnetoresistive element 100 and the transistor Tr is covered by the insulating layer In. The insulating layer In is an insulating layer that insulates between the wirings and between the elements of the multilayer wiring. The insulating layer In is, for example, silicon oxide (SiO x ), silicon nitride (SiN x ), silicon carbide (SiC), chromium nitride, silicon carbonitride (SiCN), silicon oxynitride (SiON), aluminum oxide (Al2O3), zirconium oxide (ZrO x ), etc.

[0055] The structure of the cross section passing through the first reference element 101 and the second reference element 102 is substantially the same as the structure of the cross section of the magnetoresistive element 100.

[0056] Figure 3 is a cross-sectional view of the magnetoresistive element 100 of the first embodiment. Figure 4 is a top view of the magnetoresistive element 100 of the first embodiment. Figure 3 is a cross section obtained by cutting the magnetoresistive element 100 with an xz plane passing through the center of the width of the wiring 20 in the y direction.

[0057] The magnetoresistive element 100 includes, for example, a laminate 10, a wiring 20, and conductive portions 31, 32. The resistance value of the laminate 10 in the z direction changes by injecting spins from the wiring 20 into the laminate 10. The magnetoresistive element 100 is a spin element that utilizes spin-orbit torque (SOT), and is sometimes referred to as a spin-orbit torque type magnetoresistive element, a spin injection type magnetoresistive element, or a spin current magnetoresistive element. In addition, the wiring 20 is sometimes referred to as a spin-orbit torque wiring.

[0058] The laminate 10 is laminated on the wiring 20. Other layers may also be provided between the laminate 10 and the wiring 20. The laminate 10 is sandwiched between the wiring 20 and the electrode E in the z direction. The laminate 10 is a columnar body. The top view shape of the laminate 10 in the z direction is, for example, circular, elliptical, or quadrilateral.

[0059] The laminate 10 has a first ferromagnetic layer 1, a second ferromagnetic layer 2, and a nonmagnetic layer 3. The first ferromagnetic layer 1 is connected to, for example, the wiring 20 and laminated on the wiring 20. Spin is injected from the wiring 20 into the first ferromagnetic layer 1. The magnetization of the first ferromagnetic layer 1 is subjected to spin-orbit torque (SOT) by the injected spin, and thus the orientation direction changes. The second ferromagnetic layer 2 is in the z-direction of the first ferromagnetic layer 1. The first ferromagnetic layer 1 and the second ferromagnetic layer 2 sandwich the nonmagnetic layer 3 in the z-direction.

[0060] The first ferromagnetic layer 1 and the second ferromagnetic layer 2 each have magnetization. When a predetermined external force is applied, the magnetization of the second ferromagnetic layer 2 is less likely to change in the orientation direction compared to the magnetization of the first ferromagnetic layer 1. The first ferromagnetic layer 1 is sometimes referred to as a magnetization-free layer, and the second ferromagnetic layer 2 is sometimes referred to as a magnetization-fixed layer or a magnetization-reference layer. The resistance value of the laminate 10 varies depending on the relative angle of the magnetizations of the first ferromagnetic layer 1 and the second ferromagnetic layer 2 sandwiching the nonmagnetic layer 3.

[0061] The first ferromagnetic layer 1 and the second ferromagnetic layer 2 contain ferromagnetic materials. The ferromagnetic material is, for example, a metal selected from the group consisting of Cr, Mn, Co, Fe, and Ni, an alloy containing one or more of these metals, an alloy containing at least one of these metals and one or more elements of B, C, and N, etc. The ferromagnetic material is, for example, Co-Fe, Co-Fe-B, Ni-Fe, Co-Ho alloy, Sm-Fe alloy, Fe-Pt alloy, Co-Pt alloy, CoCrPt alloy.

[0062] The first ferromagnetic layer 1 and the second ferromagnetic layer 2 may also contain Heusler alloys. The Heusler alloy contains an intermetallic compound having a chemical composition of XYZ or X2YZ. X is a transition metal element or a noble metal element of the Co, Fe, Ni, or Cu group in the periodic table, Y is a transition metal of the Mn, V, Cr, or Ti group or an element species of X, and Z is a typical element of Group III to Group V. The Heusler alloy is, for example, Co2FeSi, Co2FeGe, Co2FeGa, Co2MnSi, Co2Mn 1－a FeaAl b Si 1－b 、Co2FeGe 1－c Ga c etc. The Heusler alloy has a high spin polarization rate.

[0063] The laminate 10 may also have an antiferromagnetic layer via a spacer layer on the surface of the second ferromagnetic layer 2 opposite to the nonmagnetic layer 3. The second ferromagnetic layer 2, the spacer layer, and the antiferromagnetic layer form a synthetic antiferromagnetic structure (SAF structure). The synthetic antiferromagnetic structure is composed of two magnetic layers sandwiching a nonmagnetic layer. By antiferromagnetically coupling the second ferromagnetic layer 2 and the antiferromagnetic layer, the coercive force of the second ferromagnetic layer 2 becomes larger than in the case where no antiferromagnetic layer is provided. The antiferromagnetic layer is, for example, IrMn, PtMn, etc. The spacer layer contains, for example, at least one selected from the group consisting of Ru, Ir, and Rh.

[0064] The laminate 10 may also have a layer other than the first ferromagnetic layer 1, the second ferromagnetic layer 2, and the nonmagnetic layer 3. For example, a base layer may be provided between the wiring 20 and the laminate 10. The base layer improves the crystallinity of each layer constituting the laminate 10.

[0065] The wiring 20 is in contact with, for example, one surface of the laminate 10. The wiring 20 is a write wiring for writing data to the magnetoresistive element 100. The wiring 20 extends in the x direction. At least a part of the wiring 20 sandwiches the first ferromagnetic layer 1 in the z direction together with the nonmagnetic layer 3.

[0066] When a current I flows through the wiring 20, a spin current is generated by the spin Hall effect, and spins are injected into the first ferromagnetic layer 1. For example, the wiring 20 gives a spin-orbit torque (SOT) that can reverse the magnetization of the first ferromagnetic layer 1 as much as possible to the magnetization of the first ferromagnetic layer 1. The spin Hall effect is a phenomenon in which, when a current flows, a spin current is induced in a direction orthogonal to the direction of current flow based on the spin-orbit interaction. The spin Hall effect is common with the normal Hall effect in that the moving (moving) charge (electron) is bent in the direction of motion (movement). In the normal Hall effect, the direction of motion of charged particles moving in a magnetic field is bent by the Lorentz force. In contrast, in the spin Hall effect, even in the absence of a magnetic field, the moving direction of spins is bent only by the movement of electrons (only by the flowing current).

[0067] For example, when a current flows through the wiring 20, the first spins oriented in one direction and the second spins oriented in the direction opposite to the first spins are bent in the direction orthogonal to the direction of current I flow by the spin Hall effect. For example, the first spins oriented in the -y direction are bent in the +z direction, and the second spins oriented in the +y direction are bent in the -z direction.

[0068] In a non-magnetic material (a material that is not ferromagnetic), the number of electrons with the first spin and the number of electrons with the second spin generated by the spin Hall effect are equal. That is, the number of electrons with the first spin in the +z direction and the number of electrons with the second spin in the -z direction are equal. The first spin and the second spin flow in the direction of relieving the spin imbalance. During the movement of the first spin and the second spin in the z direction, the flow of charge cancels each other out, so the current becomes zero. The spin current not accompanied by current is particularly called a pure spin current.

[0069] When the flow of electrons with the first spin is represented as J ↑ and the flow of electrons with the second spin is represented as J ↓ and the spin current is represented as J S then it is defined as J S = J ↑ - J ↓ . The spin current J S is generated in the z direction. The first spin is injected from the wiring 20 into the first ferromagnetic layer 1.

[0070] The wiring 20 includes any one of a metal, an alloy, an intermetallic compound, a metal boride, a metal carbide, a metal silicide, and a metal phosphide having a function of generating a spin current by the spin Hall effect when a current I flows.

[0071] The wiring 20 includes, for example, a non-magnetic heavy metal as the main element. The main element is the element with the highest proportion among the elements constituting the wiring 20. The wiring 20 includes, for example, a heavy metal having a specific gravity of yttrium (Y) or more. Among non-magnetic heavy metals, the atomic number is 39 or more, the atomic number is large, and there are d electrons or f electrons in the outermost shell, so the spin-orbit interaction is strongly generated. The spin Hall effect is generated by the spin-orbit interaction, so the spin is likely to be uneven in the wiring 20, and the spin current J S is easily generated. The wiring 20 includes, for example, any one selected from the group consisting of Au, Hf, Mo, Pt, W, and Ta.

[0072] The wiring 20 may also include a magnetic metal. The magnetic metal is a ferromagnetic metal or an antiferromagnetic metal. A trace amount of magnetic metal contained in the non-magnetic material becomes a spin diffusion factor. The trace amount is, for example, 3% or less of the total molar ratio of the elements constituting the wiring 20. When the spin diffuses due to the magnetic metal, the spin-orbit interaction is enhanced, and the generation efficiency of the spin current with respect to the current becomes high.

[0073] The wiring 20 may also include a topological insulator. A topological insulator is a substance that is an insulator or a high-resistance body inside, but has a metallic state with spin polarization on its surface. A topological insulator generates an internal magnetic field through spin-orbit interaction. Even without an external magnetic field, a topological insulator can discover new topological phases through the effect of spin-orbit interaction. A topological insulator can efficiently generate a pure spin current through strong spin-orbit interaction and the breaking of inversion symmetry at the edges.

[0074] Examples of topological insulators include SnTe, Bi 1.5 Sb 0.5 Te 1.7 Se 1.3 、TlBiSe2, Bi2Te3, Bi 1－x Sb x 、(Bi 1－ x Sb x )2Te3, etc. Topological insulators can efficiently generate spin currents.

[0075] When viewed from the z-direction, the conductive part 31 and the conductive part 32 sandwich the laminate 10 in the x-direction. The conductive parts 31 and 32 electrically connect, for example, elements and wirings in different layers. The conductive parts 31 and 32 are made of materials with excellent conductivity. The conductive parts 31 and 32 include, for example, at least one selected from the group consisting of Ag, Cu, Co, Al, and Au.

[0076] Figure 5 is a top view of the first reference element 101 of the first embodiment. The first reference element 101 includes, for example, a laminate 10, a wiring 21, and conductive parts 31 and 32. The first reference element 101 has the same structure as the magnetoresistive effect element 100 except that the wiring width w21 of the wiring 21 is narrower than the wiring width w20 of the wiring 20 of the magnetoresistive effect element 100.

[0077] The wiring width w21 of the wiring 21 is narrower than the wiring width w20 of the wiring 20. The wiring width w21 is, for example, 95% or less of the wiring width w20, and may also be 90% or less. The wiring width w20 is the average value of the wiring widths in the y-direction of a plurality of magnetoresistive effect elements 100. When the wiring width w21 is narrow enough, even considering manufacturing deviations, the wiring width w21 is much narrower than the wiring width w20.

[0078] The wiring 21 is made of, for example, the same material as the wiring 20. The resistance of the wiring 21 is higher than the resistance of the wiring 20. The resistance of the wiring 21 is, for example, 105% or more of the resistance of the wiring 20, and may also be 110% or more. The resistance of the wiring 20 is the average value of the resistances of the wirings 20 of a plurality of magnetoresistive effect elements 100.

[0079] Figure 6 It is a top view of the second reference element 102 of the first embodiment. The second reference element 102 includes, for example, a laminate 10, wirings 22, and conductive portions 31 and 32. The second reference element 102 has the same structure as the magnetoresistive element 100 except that the wiring width w22 of the wiring 22 is wider than the wiring width w20 of the wiring 20 of the magnetoresistive element 100.

[0080] The wiring width w22 of the wiring 22 is wider than the wiring width w20 of the wiring 20. The wiring width w22 is, for example, 105% or more of the wiring width w20, and may be 110% or more. When the wiring width w22 is wide enough, even considering manufacturing deviations, the wiring width w22 is wide enough compared to the wiring width w20.

[0081] The wiring 22 is made of, for example, the same material as the wiring 20. The resistance of the wiring 22 is lower than the resistance of the wiring 20. The resistance of the wiring 22 is, for example, 95% or less of the resistance of the wiring 20, and may be 90% or less.

[0082] Next, a method for manufacturing the magnetoresistive element 100 will be described. The magnetoresistive element 100 is formed by a layer stacking process for each layer and a processing process for processing a part of each layer into a specified shape. The layer stacking for each layer can use a sputtering method, a chemical vapor deposition (CVD) method, an electron beam deposition method (EB deposition method), an atomic laser deposition method, etc. The processing for each layer can be performed using a photolithography method or the like.

[0083] First, impurities are doped at a specified position on the substrate Sub to form a source electrode S and a drain electrode D. Next, a gate insulating film GI and a gate electrode G are formed between the source electrode S and the drain electrode D. The source electrode S, the drain electrode D, the gate insulating film GI, and the gate electrode G form a transistor Tr.

[0084] Next, an insulating layer In is formed to cover the transistor Tr. In addition, an opening is formed in the insulating layer In, and a conductor is filled in the opening, thereby forming a via wiring Via, and conductive portions 31 and 32. After the insulating layer In is stacked to a specified thickness, a groove is formed in the insulating layer In, and a conductor is filled in the groove, thereby forming a write wiring Wp and a common wiring Cm.

[0085] Next, a wiring layer, a ferromagnetic layer, a non-magnetic layer, and a ferromagnetic layer are sequentially formed on the surfaces of the insulating layer In, the conductive portions 31 and 32. Next, the wiring layer is processed into a specified shape. By processing the wiring layer into a specified shape, it becomes wirings 20, 21, and 22. Next, the laminate formed on the wiring layer is processed into a specified shape to form the laminate 10, whereby the magnetoresistive element 100, the first reference element 101, and the second reference element 102 can be manufactured.

[0086] Next, the operation and control method of the magnetic recording array 200 of the first embodiment will be described. Figure 7 It is a flowchart of an example of the operation of the magnetic recording array 200 of the first embodiment.

[0087] First, a write operation is performed on the magnetoresistive element 100 for recording data (step S1). The first switching element SW1 and the second switching element SW2 connected to the magnetoresistive element 100 for recording data are set to ON. When the first switching element SW1 and the second switching element SW2 are set to ON, a potential difference is generated in the longitudinal direction of the wiring 20, and a write current flows. When a write current flows through the wiring 20, the spin Hall effect is generated, and thus spins are injected into the first ferromagnetic layer 1. The spins injected into the first ferromagnetic layer 1 add spin-orbit torque (SOT) to the magnetization of the first ferromagnetic layer 1, changing the orientation direction of the magnetization of the first ferromagnetic layer 1. When the direction of the current flow is reversed, the direction of the spins injected into the first ferromagnetic layer 1 becomes opposite, and thus the orientation direction of the magnetization can be freely controlled.

[0088] The resistance value in the stacking direction of the stack 10 decreases when the magnetization of the first ferromagnetic layer 1 and the magnetization of the second ferromagnetic layer 2 are parallel, and increases when the magnetization of the first ferromagnetic layer 1 and the magnetization of the second ferromagnetic layer 2 are antiparallel. As the resistance value in the stacking direction of the stack 10, data is recorded in the magnetoresistive element 100.

[0089] In addition, when a write operation is performed on the magnetoresistive element 100, the same write operation is also performed on the magnetoresistive element 100 and the first reference element 101 and the second reference element 102 that form a pair (step S2). The magnetoresistive element 100 and the first reference element 101 and the second reference element 102 that form a pair are, for example, the first reference element 101 and the second reference element 102 connected to the same write wirings Wp1 to Wpn as the magnetoresistive element 100. The voltages applied to the wirings 21 and 22 of the first reference element 101 and the second reference element 102 are the same as those of the magnetoresistive element 100. The same load as that of the magnetoresistive element 100 is applied to the first reference element 101 and the second reference element.

[0090] Next, it is confirmed whether the magnetoresistive element 100 operates properly. The operation confirmation of the magnetoresistive element 100 is performed by reading out data from the elements that have undergone the write operation and comparing the respective data.

[0091] Read the data of the magnetoresistive element 100 in which data has been read and written (step S3). Turn on the second switching element SW2 and the third switching element SW3 connected to the magnetoresistive element 100 for reading data. When the second switching element SW2 and the third switching element SW3 are turned on, a potential difference is generated in the stacking direction of the laminate 10, and a read current flows. When a read current flows through the laminate 10, the resistance value of the magnetoresistive element 100 in the stacking direction is obtained according to Ohm's law.

[0092] Perform the same operation on the first reference element 101 and the second reference element 102 (step S4). Read the resistance values of the first reference element 101 and the second reference element 102 in the stacking direction as data.

[0093] Next, compare the resistance values of the magnetoresistive element 100, the first reference element 101, and the second reference element 102 (step S5). The resistance value is, for example, the resistance between the electrode E and the conductive portion 32. The resistance of the wiring 21 is higher than the resistance of the wiring 20. Therefore, in the case of proper operation, the resistance of the first reference element 101 is higher than the resistance of the magnetoresistive element 100. In addition, the resistance of the wiring 22 is lower than the resistance of the wiring 20. Therefore, in the case of proper operation, the resistance of the second reference element 102 is lower than the resistance of the magnetoresistive element 100.

[0094] Finally, based on the comparison result, determine the state of the magnetoresistive element 100 (step S6). When the resistance of the magnetoresistive element 100 is between the resistance of the first reference element 101 and the resistance of the second reference element 102, it is determined that the magnetoresistive element 100 is operating normally. On the other hand, when the resistance of the magnetoresistive element 100 is not between the resistance of the first reference element 101 and the resistance of the second reference element 102, it is determined that the magnetoresistive element 100 has a failure.

[0095] As a case of the failure of the magnetoresistive element 100, there is deterioration or breakage of the wiring 20 between the laminate 10 and the conductive portions 31 and 32. When the wiring 20 deteriorates or breaks, an appropriate writing operation cannot be performed. For example, in Figure 3 In the case of the magnetoresistive element 100 shown, when the wiring 20 between the laminate 10 and the conductive portion 31 deteriorates or breaks, a writing operation cannot be performed, but a reading operation can be performed. This is because the writing current flowing between the conductive portion 31 and the conductive portion 32 cannot flow normally, but the reading current between the laminate 10 and the conductive portion 32 flows normally. In this case, data may be read without noticing that the data has not been written, thereby increasing the risk of misreading of the data.

[0096] In contrast, if the resistance value of the magnetoresistive element 100 is compared with that of the first reference element 101 and the second reference element 102, the risk of misreading data is reduced. This is because even if deterioration or breakage occurs in parts other than the read path of the magnetoresistive element 100, it will not affect the resistance of the magnetoresistive element 100. By comparing the resistance of the magnetoresistive element 100 with the resistances of the first reference element 101 and the second reference element 102, abnormalities in the magnetoresistive element 100 can be appropriately detected.

[0097] The magnetoresistive element 100 determined to be faulty is set to read-only or unusable in subsequent operations.

[0098] When the magnetoresistive element 100 is set to read-only, the write operation to the magnetoresistive element 100 is prohibited. The magnetoresistive element 100 always outputs the same data. The magnetoresistive element 100 with the write operation prohibited can be used as a reference point where the data does not change, for example.

[0099] When the magnetoresistive element 100 is set to unusable, the write and read operations to the magnetoresistive element 100 are prohibited. In subsequent operations, the write and read of data to the unusable magnetoresistive element 100 are replaced with other magnetoresistive elements 100. Here, replacing with other magnetoresistive elements 100 means removing the unusable magnetoresistive element 100 and, without replacing it with other elements, replacing the write and read of data to the unusable magnetoresistive element 100 with other magnetoresistive elements 100 on the system.

[0100] As described above, the magnetic recording array 200 of the present embodiment can evaluate the presence or absence of a fault in the magnetoresistive element 100 in real time by comparing the resistances of the first reference element 101 and the second reference element 102 with the resistance of the magnetoresistive element 100.

[0101] In addition, since the first reference element 101 and the second reference element 102 are in the same temperature environment as the magnetoresistive element 100, it is possible to suppress fluctuations in the reference point of the threshold for recording data due to temperature changes. Furthermore, since the first reference element 101 and the second reference element 102 are given the same load as the magnetoresistive element 100, it is possible to suppress fluctuations in the reference point of the threshold for recording data due to deterioration.

[0102] Therefore, the magnetic recording array 200 of the present embodiment has a low risk of misreading data and high reliability.

[0103] So far, an example of the first embodiment has been illustrated, but the present invention is not limited to this example.

[0104] For example, in the above-described embodiment, the different resistances of the wirings 20, 21, and 22 are achieved by the wiring widths w20, w21, and w22, but the difference in resistance can also be generated by means other than the wiring widths w20, w21, and w22.

[0105] Figure 8 It is a cross-sectional view of the first reference element 101A of the first modification. Figure 9 It is a cross-sectional view of the second reference element 102A of the first modification. The first reference element 101A includes, for example, a laminate 10, a wiring 23, and conductive portions 31 and 32. The second reference element 102A includes, for example, a laminate 10, a wiring 24, and conductive portions 31 and 32. The first reference element 101A and the second reference element 102A are configured with the same structure as the magnetoresistive effect element 100, except that the thicknesses t23 and t24 of the wirings 23 and 24 are different from the thickness t20 of the wiring 20 of the magnetoresistive effect element 100.

[0106] The thickness t23 of the wiring 23 is thinner than the thickness t20 of the wiring 20. The thickness t23 is, for example, 95% or less of the thickness t20, and may be 90% or less. When the thickness t23 is sufficiently thin, even considering manufacturing deviations, the thickness t23 is sufficiently thinner than the thickness t20.

[0107] The wiring 23 is made of, for example, the same material as the wiring 20. The resistance of the wiring 23 is higher than the resistance of the wiring 20. The resistance of the wiring 23 is, for example, 105% or more of the resistance of the wiring 20, and may be 110% or more.

[0108] The thickness t24 of the wiring 24 is thicker than the thickness t20 of the wiring 20. The thickness t24 is, for example, 105% or more of the thickness t20, and may be 110% or more. When the thickness t24 is sufficiently thick, even considering manufacturing deviations, the thickness t24 is sufficiently thicker than the thickness t20.

[0109] The wiring 24 is made of, for example, the same material as the wiring 20. The resistance of the wiring 24 is lower than the resistance of the wiring 20. The resistance of the wiring 24 is, for example, 95% or less of the resistance of the wiring 20, and may be 90% or less.

[0110] In addition, the resistance of each wiring can be changed by changing the material of the wiring of each of the magnetoresistive effect element, the first reference element, and the second reference element. In addition, the parameters of the wiring width, thickness, and material can be combined to change the resistance of each wiring.

[0111] "Second Embodiment"

[0112] Figure 10 It is a cross-sectional view of the magnetization rotation element 110 of the second embodiment. Figure 10This is a cross-section obtained by cutting the magnetization rotation element 110 with an xz plane passing through the center of the width of the wiring 20 in the y direction. The magnetization rotation element 110 of the second embodiment is different from the magnetoresistive effect element 100 of the first embodiment in that it does not have the nonmagnetic layer 3 and the second ferromagnetic layer 2. Other structures are the same as those of the magnetoresistive effect element 100 of the first embodiment, and the description thereof is omitted.

[0113] The magnetization rotation element 110 is an example of a spin element. For example, light is incident on the first ferromagnetic layer 1 of the magnetization rotation element 110, and the light reflected by the first ferromagnetic layer 1 is evaluated. When the orientation direction of the magnetization changes due to the magneto-optical Kerr effect, the polarization state of the reflected light changes. The magnetization rotation element 110 can be used, for example, as an optical element such as an image display device that utilizes the difference in the polarization state of light.

[0114] In addition, the magnetization rotation element 110 can also be used alone as an optical element that utilizes an anisotropic magnetic sensor, the magneto-Faraday effect, etc.

[0115] The first reference element and the second reference element in the second embodiment are configured with the same structure as the magnetization rotation element 110 except for the resistance of the wiring.

[0116] By simply removing the nonmagnetic layer 3 and the second ferromagnetic layer 2 from the magnetization rotation element 110 of the second embodiment, the same effects as those of the magnetoresistive effect element 100 of the first embodiment can be obtained. In addition, the same modification examples as those of the magnetoresistive effect element 100 of the first embodiment are selected.

[0117] "Third Embodiment"

[0118] Figure 11 This is a cross-sectional view of the magnetoresistive effect element 120 of the third embodiment. Figure 11 This is a cross-section obtained by cutting the magnetoresistive effect element 120 with an xz plane passing through the center of the width of the wiring 40 in the y direction. The magnetoresistive effect element 120 is different from the magnetoresistive effect element 100 in that the stack 11 of the magnetoresistive effect element 120 is composed of a nonmagnetic layer 5 and a first ferromagnetic layer 4 starting from the side closer to the wiring 40. The same structures as those of the magnetoresistive effect element 100 are denoted by the same reference numerals, and the description thereof is omitted.

[0119] The magnetoresistive effect element 120 includes a stack 11, a wiring 40, and conductive portions 31 and 32. The stack 11 is composed of a nonmagnetic layer 5 and a first ferromagnetic layer 4 starting from the side closer to the wiring 40. The magnetoresistive effect element 120 is an element whose resistance value changes by the movement of magnetic domain walls DW, and is sometimes referred to as a magnetic domain wall movement element or a magnetic domain wall movement type magnetoresistive effect element.

[0120] The wiring 40 is a magnetic layer. The wiring 40 contains a ferromagnetic material. The magnetic material constituting the wiring 40 can be a metal selected from the group consisting of Cr, Mn, Co, Fe, and Ni, an alloy containing one or more of these metals, an alloy containing at least one of these metals and elements such as B, C, and N, and the like. Specifically, Co—Fe, Co—Fe—B, and Ni—Fe are cited.

[0121] The wiring 40 is a layer capable of magnetically recording information according to changes in the internal magnetic state. The wiring 21 has a first magnetic region 41 and a second magnetic region 42 inside. The magnetization of the first magnetic region 41 and the magnetization of the second magnetic region 42 are oriented, for example, in opposite directions. The boundary between the first magnetic region 41 and the second magnetic region 42 is a magnetic domain wall DW. The wiring 40 can have a magnetic domain wall DW inside.

[0122] The magnetoresistive effect element 120 can record data in a multi-valued or continuous manner by the position of the magnetic domain wall DW of the wiring 40. The data recorded in the wiring 40 is read as a change in the resistance value of the magnetoresistive effect element 120 when a read current is applied.

[0123] The magnetic domain wall DW moves by flowing a write current in the x direction along the wiring 40 or applying an external magnetic field. For example, when a write current (for example, a current pulse) is applied in the +x direction to the wiring 40, electrons flow in the -x direction opposite to the current, and thus the magnetic domain wall DW moves in the -x direction. When the current flows from the first magnetic region 41 toward the second magnetic region 42, the electrons spin-polarized in the second magnetic region 42 reverse the magnetization of the first magnetic region 41. By reversing the magnetization by the magnetization of the first magnetic region 41, the magnetic domain wall DW moves in the -x direction.

[0124] The first ferromagnetic layer 4 and the nonmagnetic layer 5 are the same as the first ferromagnetic layer 1 and the nonmagnetic layer 3 of the first embodiment, respectively.

[0125] The first reference element and the second reference element in the third embodiment are configured in the same structure as the magnetoresistive effect element 120 except for the resistance of the wiring.

[0126] The magnetoresistive effect element 120 of the third embodiment can also obtain the same effects as the magnetoresistive effect element 100 of the first embodiment. In addition, the magnetoresistive effect element 120 of the third embodiment can select the same modification examples as the magnetoresistive effect element 100 of the first embodiment.

[0127] The magnetic recording arrays of the first embodiment to the third embodiment can be applied to neuromorphic devices. A neuromorphic device is an element that simulates the human brain through a neural network. A neuromorphic device artificially simulates the relationship between neurons and nerve impulses in the human brain.

[0128] Neuromorphic devices, for example, have chips configured in a hierarchical manner (neurons in the brain) and communication units that connect them (synapses in the brain). Neuromorphic devices learn through the communication units (synapses) to increase the correct answer rate of problems. Learning is to discover knowledge for future use from information, and in neuromorphic devices, weights are assigned to the input data.

[0129] Each synapse performs a product-sum operation mathematically. The magnetic recording arrays of the first to third embodiments can perform a product-sum operation by arranging magnetoresistive effect elements or magnetization rotation elements in an array. For example, when a current flows through the read path of a magnetoresistive effect element, the product of the input current and the resistance of the magnetoresistive effect element is output, and a product operation is performed. When multiple magnetoresistive effect elements are connected through a common wiring, the product-sum operation is added through the common wiring, and a sum operation is performed. Therefore, the magnetic recording arrays of the first to third embodiments can be applied as product-sum operation units to neuromorphic devices.

[0130] Symbol Explanation

[0131] 1, 4 First ferromagnetic layer

[0132] 2 Second ferromagnetic layer

[0133] 3, 5 Non-magnetic layer

[0134] 10, 11 Stack

[0135] 20, 21, 22, 23, 24, 40 Wiring

[0136] 101, 101A First reference element

[0137] 102, 102A Second reference element

[0138] 200 Magnetic recording array

[0139] DW Magnetic domain wall

[0140] t20, t23, t24 Thickness

[0141] w20, w21, w22 Wiring width.

Claims

1. A magnetic recording array, comprising: a plurality of spin elements, a first reference element, and a second reference element, wherein the plurality of spin elements, the first reference element, and the second reference element each have a wiring line and a laminate including a first ferromagnetic layer laminated on the wiring line, the resistance of the wiring line of the first reference element is higher than the resistance of the wiring line of each spin element, and the resistance of the wiring line of the second reference element is lower than the resistance of the wiring line of each spin element.

2. The magnetic recording array according to claim 1, wherein the width of the wiring line of the first reference element is narrower than the width of the wiring line of the spin element, and the width of the wiring line of the second reference element is wider than the width of the wiring line of the spin element.

3. The magnetic recording array according to claim 1 or 2, wherein the thickness of the wiring line of the first reference element is thinner than the thickness of the wiring line of the spin element, and the thickness of the wiring line of the second reference element is thicker than the thickness of the wiring line of the spin element.

4. The magnetic recording array according to any one of claims 1 to 3, wherein the wiring lines of the spin element, the first reference element, and the second reference element are each made of the same material.

5. The magnetic recording array according to any one of claims 1 to 4, wherein the resistance of the wiring line of the first reference element is 105% or more of the resistance of the wiring line of the spin element, and the resistance of the wiring line of the second reference element is 95% or less of the resistance of the wiring line of the spin element.

6. The magnetic recording array according to any one of claims 1 to 5, wherein a power supply generates a potential difference along the length direction of the wiring lines of the plurality of spin elements, the first reference element, and the second reference element, and the power supply applies the same voltage to the wiring lines of the plurality of spin elements, the first reference element, and the second reference element.

7. The magnetic recording array according to any one of claims 1 to 6, wherein the laminate has, from the side closer to the wiring line, the first ferromagnetic layer, a non-magnetic layer, and a second ferromagnetic layer, and the wiring line is any one of a metal, an alloy, an intermetallic compound, a metal boride, a metal carbide, a metal silicide, and a metal phosphide having a function of generating a spin current due to the spin Hall effect when current flows.

8. The magnetic recording array according to any one of claims 1 to 6, wherein the laminate has, from the side closer to the wiring line, a non-magnetic layer and the first ferromagnetic layer, and the wiring line is a ferromagnetic layer capable of having magnetic domain walls inside.

9. A neuromorphic device having the magnetic recording array according to any one of claims 1 to 8.

10. A control method for a magnetic recording array, which is a control method for the magnetic recording array according to any one of claims 1 to 8, comprising: a step of applying the same write voltage to the wiring lines of the spin element to be written, the first reference element, and the second reference element among the plurality of spin elements; a step of applying a read voltage along the stacking direction of the elements to which the write voltage has been applied; and a step of comparing the resistance of the spin element with the resistances of the first reference element and the second reference element.

11. The control method of the magnetic recording array according to claim 10, wherein, when comparing the resistance of the spin element with the resistances of the first reference element and the second reference element, if the resistance of the spin element is not between the resistance of the first reference element and the resistance of the second reference element, writing to the spin element is prohibited.

12. The control method of the magnetic recording array according to claim 10 or 11, wherein, when comparing the resistance of the spin element with the resistances of the first reference element and the second reference element, if the resistance of the spin element is not between the resistance of the first reference element and the resistance of the second reference element, writing and reading data to and from the spin element are replaced with other elements.

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