Magnetic elements and integrated devices

Abstract

To provide a magnetic element and a magnetic array that can make the current density required to rotate the magnetization low.SOLUTION: A magnetic element 100 includes a first ferromagnetic layer 1, a nonmagnetic layer 3, a second ferromagnetic layer 2, a gate insulating layer 4, a first electrode 5, and a second electrode 6. The nonmagnetic layer and the first electrode are connected to a first surface 1A of the first ferromagnetic layer at different positions. The second ferromagnetic layer sandwiches the nonmagnetic layer together with the first ferromagnetic layer. The second electrode is connected to a second surface 1B on the opposite side of the first surface of the first ferromagnetic layer across the gate insulating layer.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This invention relates to a magnetic element and an integrated device. [Background technology]

[0002] Giant magnetoresistance (GMR) elements, which consist of a multilayer film of a ferromagnetic layer and a non-magnetic layer, and tunnel magnetoresistance (TMR) elements, which use an insulating layer (tunnel barrier layer, barrier layer) in the non-magnetic layer, are known as magnetoresistive elements. Magnetoresistive elements can be applied to magnetic sensors, high-frequency components, magnetic heads, and non-volatile random-access memory (MRAM).

[0003] MRAM is a memory element that integrates magnetoresistive elements. MRAM reads and writes data by utilizing the property that the resistance of a magnetoresistive element changes when the direction of magnetization of two ferromagnetic layers flanking a non-magnetic layer in the magnetoresistive element changes.

[0004] Magnetoresistive elements include STT-type magnetoresistive elements and SOT-type magnetoresistive elements. STT-type magnetoresistive elements control the direction of magnetization by utilizing spin transfer torque (STT) generated by passing an electric current in the stacking direction of the magnetoresistive elements. SOT-type magnetoresistive elements control the direction of magnetization by utilizing spin current generated by spin-orbit interaction or spin-orbit torque (SOT) induced by the Rashba effect at the interface of dissimilar materials. For example, Patent Document 1 describes an STT-type magnetoresistive element. For example, Patent Document 2 describes an SOT-type magnetoresistive element. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2013-175615 [Patent Document 2] Japanese Patent Publication No. 2017-216286 [Overview of the project] [Problems that the invention aims to solve]

[0006] Both STT-type and SOT-type magnetoresistive elements share the common need for a low reversal current density. This is because being able to reverse magnetization with less energy leads to a reduction in the power consumption of the magnetoresistive element.

[0007] This invention has been made in view of the above circumstances, and aims to provide a magnetic element and a magnetic array that can reduce the current density required to rotate the magnetization. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides the following means.

[0009] (1) The magnetic element according to the first embodiment comprises a first ferromagnetic layer, a second ferromagnetic layer, a non-magnetic layer, a gate insulating layer, a first electrode, and a second electrode. The non-magnetic layer and the first electrode are connected to the first surface of the first ferromagnetic layer at different positions. The second ferromagnetic layer sandwiches the non-magnetic layer together with the first ferromagnetic layer. The second electrode is connected to the second surface of the first ferromagnetic layer opposite to the first surface, with the gate insulating layer in between.

[0010] (2) The magnetic element according to the above embodiment may further include spin-orbit torque wiring. The spin-orbit torque wiring is located between the first ferromagnetic layer and the gate insulating layer.

[0011] (3) In the magnetic element according to the above embodiment, the spin-orbit torque wiring may have a third ferromagnetic layer, a fourth ferromagnetic layer, and a spacer layer sandwiched between the third ferromagnetic layer and the fourth ferromagnetic layer. The magnetization of the third ferromagnetic layer and the magnetization of the fourth ferromagnetic layer are oriented in any direction within the plane in which the layers extend. The third ferromagnetic layer and the fourth ferromagnetic layer are antiferromagnetically coupled.

[0012] (4) In the magnetic element according to the above aspect, the magnetization of the first ferromagnetic layer may be oriented in the stacking direction.

[0013] (5) The magnetic element according to the above aspect may further include a resistance layer and a third electrode. The resistance layer is between the gate insulating layer and the second electrode. The third electrode is connected to the resistance layer at a position different from the second electrode.

[0014] (6) In the magnetic element according to the above aspect, the resistance layer may be an oxide containing any one or more elements selected from the group consisting of Ir, W, Pd, Mo, Nb, Re, Fe, Cr, V, Ti, Ru, Sn, In, Zr, and Cu.

[0015] (7) The integrated device according to the second aspect includes a plurality of magnetic elements. Each of the plurality of magnetic elements is a magnetic element according to the above aspect.

[0016] (8) In the integrated device according to the above aspect, at least two of the plurality of magnetic elements may share the gate insulating layer.

[0017] (9) The integrated device according to the above aspect may further include a conductive layer. The conductive layer is between the second electrode and the gate insulating layer and is connected to the second electrodes of different magnetic elements.

[0018] (10) The integrated device according to the above aspect may further include a connection portion. The connection portion electrically connects at least two of the first electrodes of the plurality of magnetic elements or between the first electrode and the second ferromagnetic layer.

Advantages of the Invention

[0019] The magnetic element and the integrated device according to the present invention can reduce the current density required to rotate the magnetization.

Brief Description of the Drawings

[0020] [ [Figure 1]It is a circuit diagram of an integrated device according to the first embodiment. [Figure 2] It is a cross-sectional view of a characteristic portion of an integrated device according to the first embodiment. [Figure 3] It is a cross-sectional view of a magnetic element according to the first embodiment. [Figure 4] It is a plan view of a magnetic element according to the first embodiment. [Figure 5] It is a circuit diagram of an integrated device according to the first modification. [Figure 6] It is a cross-sectional view of a magnetic element according to the second embodiment. [Figure 7] It is a cross-sectional view of a magnetic element according to the third embodiment. [Figure 8] It is a cross-sectional view of a magnetic element according to the fourth embodiment. [Figure 9] It is a circuit diagram of an integrated device according to the fourth embodiment. [Figure 10] It is a circuit diagram of an integrated device according to the second modification. [Figure 11] It is a cross-sectional view of an integrated device according to the fifth embodiment. [Figure 12] It is a circuit diagram of an integrated device according to the fifth embodiment. [Figure 13] It is a cross-sectional view of an integrated device according to the sixth embodiment. [Figure 14] It is a circuit diagram of an integrated device according to the sixth embodiment. [Figure 15] It is a cross-sectional view of an integrated device according to the seventh embodiment.

Modes for Carrying Out the Invention

[0021] Hereinafter, this embodiment will be described in detail with appropriate reference to the drawings. In the drawings used in the following description, for the sake of clarity of the features, there are cases where the characteristic portions are enlarged and shown, and the dimensional ratios of each component may be different from the actual ones. The materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited thereto, and it can be appropriately modified and implemented within the scope where the effects of the present invention are achieved. ;

[0022] First, let's define the directions. One direction on one side of the substrate Sub (see Figure 2), described later, is defined as the x-direction, and the direction perpendicular to the x-direction is defined as the y-direction. The x-direction is, for example, the direction from the first electrode 5 towards the non-magnetic layer 3 along the first ferromagnetic layer 1. The z-direction is the direction perpendicular to both the x-direction and the y-direction. The z-direction is an example of the stacking direction in which each layer is stacked. Hereafter, the +z direction may be expressed as "up" and the -z direction as "down". Up and down do not necessarily coincide with the direction in which gravity acts.

[0023] In this specification, "extending in the x-direction" means, for example, that the dimension in the x-direction is greater than the smallest dimension among the x, y, and z directions. The same applies to extensions in other directions. In this specification, "connection" is not limited to physical connections. For example, it is not limited to cases where two layers are physically touching, but also includes cases where two layers are connected by another layer in between. In this specification, "connection" also includes electrical connections.

[0024] "First Embodiment" Figure 1 is a circuit diagram of an integrated circuit 200 according to the first embodiment. The integrated circuit 200 comprises a plurality of magnetic elements 100, a voltage source 110, a plurality of first wirings L1, a plurality of second wirings L2, a plurality of gate lines GL, a plurality of first switching elements Sw1, and a plurality of second switching elements Sw2.

[0025] The magnetic elements 100 are arranged, for example, in a matrix within the xy-plane. Details of the magnetic elements 100 will be described later. Each of the magnetic elements 100 is connected to the first switching element Sw1.

[0026] The first switching element Sw1 is connected, for example, to the first wiring L1. In Figure 1, the first switching element Sw1 is located between the first wiring L1 and each of the magnetic elements 100. The second switching element Sw2 is located at one end of the first wiring L1. The second switching element Sw2 is located, for example, outside the integration area. The first switching element Sw1 and the second switching element Sw2 can be used to select which magnetic element 100 carries the write current or read current.

[0027] Each of the first wirings L1 electrically connects a power source to one or more magnetic elements 100. The first wirings L1 are connected, for example, to the second ferromagnetic layer 2 of the magnetic element 100, which will be described later. Each of the second wirings L2 electrically connects a reference potential to one or more magnetic elements 100. The reference potential is, for example, ground. The second wirings L2 are connected, for example, to the first electrode 5 of the magnetic element 100, which will be described later. The power source is connected to the integrated unit 200 when in use.

[0028] The first switching element Sw1 and the second switching element Sw2 are elements that control the flow of current. The first switching element Sw1 and the second switching element Sw2 are, for example, elements that utilize a phase change in the crystal layer, such as transistors and ovonic threshold switches (OTS), elements that utilize a change in band structure, such as metal-insulator transition (MIT) switches, elements that utilize a breakdown voltage, such as Zener diodes and avalanche diodes, and elements whose conductivity changes with changes in atomic position.

[0029] The voltage source 110 is connected to the first electrode 5 and the second electrode 6 of the magnetic element 100, which will be described later. The voltage source 110 generates a potential difference between the first electrode 5 and the second electrode 6.

[0030] Figure 2 is a cross-sectional view of a characteristic part of the integrated apparatus according to the first embodiment. Figure 2 is a cross-section obtained by cutting through the xz plane passing through the center of the width in the y direction of the magnetic element 100.

[0031] The first switching element Sw1 shown in Figure 2 is a transistor Tr. The transistor Tr is, for example, a field-effect transistor and has a gate electrode G, a gate insulating film GI, and a source S and drain D formed on a substrate Sub. The source S and drain D are determined by the direction of current flow and are in the same region. The positional relationship between the source S and drain D may be inverted. The substrate Sub is, for example, a semiconductor substrate. The second switching element Sw2 is located at a position shifted in the x-direction.

[0032] The transistor Tr and the magnetic element 100 are electrically connected via via wiring V and wiring W. The transistor Tr is also connected to the gate line GL or source line SL via via wiring V. Via wiring V extends, for example, in the z-direction. Wiring W extends in any direction within the plane. Via wiring V and wiring W are conductors.

[0033] The magnetic element 100 and the transistor Tr are covered with an insulating layer In. The insulating layer In is an insulating layer that insulates between wirings in multilayer wiring and between elements. The insulating layer In is made of, 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 (ZrO3) x Examples include magnesium oxide (MgO), aluminum nitride (AlN), etc.

[0034] Figure 3 is a cross-sectional view of the magnetic element 100. Figure 3 is a cross-section obtained by cutting the magnetic element 100 through the xz plane passing through the center of its width in the y direction. Figure 4 is a plan view of the magnetic element 100 as seen from the z direction.

[0035] The magnetic element 100 comprises, for example, a first ferromagnetic layer 1, a second ferromagnetic layer 2, a non-magnetic layer 3, a gate insulating layer 4, a first electrode 5, a second electrode 6, and a conductive layer 7.

[0036] The first ferromagnetic layer 1 extends in the xy plane. The first ferromagnetic layer 1 contains a ferromagnetic material. 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 at least one element 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.

[0037] The first ferromagnetic layer 1 may contain a Heusler alloy. 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 on 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 from Group III to Group V. The Heusler alloy is, for example, Co2FeSi, Co2FeGe, Co2FeGa, Co2MnSi, Co2Mn 1-a Fe a Al b Si 1-b 、Co2FeGe 1-c Ga c etc. The Heusler alloy has a high spin polarization rate.

[0038] The magnetization M1 of the first ferromagnetic layer 1 is, for example, oriented in the z direction. The magnetization M1 may be inclined from the z direction as long as the main orientation direction is the z direction. Also, the magnetization M1 may be oriented in any direction within the xy plane.

[0039] The nonmagnetic layer 3 is connected to a part of the first surface 1A of the first ferromagnetic layer 1. The nonmagnetic layer 3 is between the first ferromagnetic layer 1 and the second ferromagnetic layer 2.

[0040] The non-magnetic layer 3 contains a non-magnetic material. When the non-magnetic layer 3 is an insulator (a tunnel barrier layer), materials such as Al2O3, SiO2, MgO, and MgAl2O4 can be used. Alternatively, materials in which some of the Al, Si, and Mg are replaced with Zn, Be, etc., may be used for the non-magnetic layer 3. Among these, MgO and MgAl2O4 are materials that can realize coherent tunneling, and therefore spin can be efficiently injected. When the non-magnetic layer 3 is a metal, materials such as Cu, Au, and Ag can be used. Furthermore, when the non-magnetic layer 3 is a semiconductor, materials such as Si, Ge, CuInSe2, CuGaSe2, and Cu(In,Ga)Se2 can be used.

[0041] The second ferromagnetic layer 2 sandwiches the non-magnetic layer 3 together with the first ferromagnetic layer 1. The second ferromagnetic layer 2 is, for example, in contact with the non-magnetic layer 3 and is located on the non-magnetic layer 3. The same material as that used for the first ferromagnetic layer 1 is used for the second ferromagnetic layer 2.

[0042] The magnetization M2 of the second ferromagnetic layer 2 is less susceptible to changes in orientation direction than the magnetization M1 of the first ferromagnetic layer 1 when a predetermined external force is applied. The first ferromagnetic layer 1 is called the magnetization free layer, and the second ferromagnetic layer 2 is called the magnetization fixed layer or magnetization reference layer. In the magnetic element 100 shown in Figure 3, the magnetization fixed layer is located on the side away from the substrate Sub, and this is called a top-pin structure. The resistance value of the magnetic element 100 changes according to the difference in the relative angle of magnetization between the first ferromagnetic layer 1 and the second ferromagnetic layer 2, which are separated by the non-magnetic layer 3.

[0043] The second ferromagnetic layer 2 may be a synthetic antiferromagnetic structure (SAF structure). A synthetic antiferromagnetic structure consists of two magnetic layers flanking a non-magnetic layer. For example, the second ferromagnetic layer 2 may be a laminate containing a ferromagnetic layer, a spacer layer, and another ferromagnetic layer. The coercivity of the second ferromagnetic layer 2 is greater than in the case of a non-SAF structure because the two ferromagnetic layers constituting the SAF structure are antiferromagnetically coupled. The magnetic layers constituting the SAF structure may include, for example, a ferromagnetic material and an antiferromagnetic material such as IrMn or PtMn. The spacer layer may include, for example, at least one selected from the group consisting of Ru, Ir, and Rh.

[0044] The first electrode 5 is in contact with a portion of the first surface 1A of the first ferromagnetic layer 1. The first electrode 5 is connected to the first surface 1A at a different position from the non-magnetic layer 3. The first electrode 5 is a conductor. The first electrode 5 is, for example, Al, Cu, etc.

[0045] The gate insulating layer 4 is in contact with, for example, the second surface 1B of the first ferromagnetic layer 1. The second surface 1B is the surface opposite to the first surface 1A of the first ferromagnetic layer 1. The gate insulating layer 4 insulates the first ferromagnetic layer 1 from the second electrode 6. The gate insulating layer 4 can be made of the same material as the gate insulating film GI and the insulating layer In.

[0046] The second electrode 6 is connected to the second surface 1B of the first ferromagnetic layer 1, with the gate insulating layer 4 in between. The second electrode 6 is a conductor. The second electrode 6 is, for example, Al, Cu, etc.

[0047] The conductive layer 7 is located between the second electrode 6 and the gate insulating layer 4. The conductive layer 7 is a layer for adjusting the potential within the gate insulating layer 4. The conductive layer 7 is made of a conductive material. The conductive layer 7 may be a metal or a conductive oxide. In the example shown in Figure 3, the conductive layer 7 makes the voltage applied to the gate insulating layer 4 uniform.

[0048] Next, a method for manufacturing the magnetic element 100 will be described. The magnetic element 100 is formed by a layer stacking process and a processing process in which a portion of each layer is processed into a predetermined shape. For the layer stacking, sputtering, chemical vapor deposition (CVD), electron beam deposition (EB deposition), atomic laser deposition, etc., can be used. For the processing of each layer, photolithography, etc., can be used.

[0049] Next, the operation of the magnetic element 100 will be explained. When the magnetic element 100 is used as a memory element, there are data writing operations and data reading operations.

[0050] First, let's explain the data writing operation. First, the first switching element Sw1 and the second switching element Sw2 connected to the data writing magnetic element 100 are turned ON. Also, the voltage source 110 provides a potential difference of a threshold or higher between the first electrode 5 and the second electrode 6. Due to the potential difference between the first electrode 5 and the second electrode 6, a voltage is applied to the first ferromagnetic layer 1. When a voltage is applied to the first ferromagnetic layer 1, the magnetization M1 of the first ferromagnetic layer 1 becomes unstable. Also, when the second switching element Sw2 is turned ON, a potential difference is created between the second ferromagnetic layer 2 and the first electrode 5, and a current flows between the second ferromagnetic layer 2 and the first electrode 5. When a current flows between the second ferromagnetic layer 2 and the first electrode 5, spin-polarized electrons are injected into the first ferromagnetic layer 1, and a spin transfer torque (STT) is applied to the first ferromagnetic layer 1. The magnetization M1 of the first ferromagnetic layer 1 is reversed by the voltage-controlled magnetic anisotropy (VCMA) effect and spin transfer torque (STT).

[0051] The resistance value of the magnetic element 100 differs depending on whether the direction of magnetization M1 of the first ferromagnetic layer 1 or the direction of magnetization M2 of the second ferromagnetic layer 2 is parallel or antiparallel. For example, data is stored by setting the case where the two magnetizations M1 and M2 are parallel to each other as "0" and the case where the two magnetizations M1 and M2 are antiparallel as "0".

[0052] Next, the data reading operation will be described. The first switching element Sw1 and the second switching element Sw2 connected to the magnetic element 100 from which data is read are turned ON. The potential difference between the first electrode 5 and the second electrode 6 is set to less than a threshold, for example, by a voltage source 110. When the second switching element Sw2 is turned ON, a potential difference is created between the second ferromagnetic layer 2 and the first electrode 5, and a current flows between the second ferromagnetic layer 2 and the first electrode 5. The amount of current during reading is made smaller than the amount of current during writing. The amount of current can be set by controlling the potential difference between the second ferromagnetic layer 2 and the first electrode 5.

[0053] Here, an example of using the magnetic element 100 as a memory element has been described, but the magnetic element can also be used as an anisotropic magnetic sensor, an optical element utilizing the magnetic Kerr effect, or the magnetic Faraday effect. For example, it can be used as an optical element by irradiating light between the second ferromagnetic layer 2 and the first electrode 5.

[0054] The magnetic element 100 according to the first embodiment controls the magnetization M1 of the first ferromagnetic layer 1 by utilizing the voltage magnetic anisotropy control effect and the spin transfer torque. Therefore, compared to an STT-type magnetoresistive element that performs magnetization reversal using only the spin transfer torque, the reversal current density required to reverse the magnetization M1 of the first ferromagnetic layer 1 can be reduced.

[0055] Up to this point, an example of the integrated device 200 has been shown, but it is not limited to this example. For example, as shown in Figure 5, the voltage source 110 may be shared by multiple magnetic elements 100. The integrated device 200A shown in Figure 5 further includes a third wiring L3 and a third switching element SW3. In Figure 5, components similar to those in the integrated device 200 are denoted by the same reference numerals and their explanations are omitted.

[0056] The third switching element SW3 is connected between the second wiring L2 and the first electrode 5. The third switching element SW3 can be the same as the first switching element SW1. The third wiring L3 is connected to the gates of the first switching element SW1 and the third switching element SW3. The third wiring L3 allows the first switching element SW1 and the third switching element SW3 to be turned ON and OFF simultaneously. During writing and reading, the first switching element SW1 and the third switching element SW3 are turned ON simultaneously via the third wiring L3.

[0057] "Second Embodiment" Figure 6 is a cross-sectional view of the magnetic element 101 according to the second embodiment. Figure 6 is a cross-section obtained by cutting the magnetic element 101 through the xz plane passing through the center of the width in the y direction. The plan view of the magnetic element 101 is substantially the same as that of Figure 4. In the magnetic element 101, components similar to those of the magnetic element 100 are given the same reference numerals and their descriptions are omitted.

[0058] Magnetic element 101 differs from magnetic element 100 in that it further has spin-orbit torque wiring 8. The spin-orbit torque wiring 8 is located between the first ferromagnetic layer 1 and the gate insulating layer 4. The spin-orbit torque wiring 8 is in contact with, for example, the second surface 1B of the first ferromagnetic layer 1.

[0059] The spin-orbit torque wiring 8 generates a spin current through the spin Hall effect when current flows through it, injecting spin into the first ferromagnetic layer 1.

[0060] The spin Hall effect is a phenomenon in which, when an electric current flows, a spin current is induced in a direction perpendicular to the direction of the current flow, based on spin-orbit interaction. The spin Hall effect is similar to the ordinary Hall effect in that the direction of motion of moving charges (electrons) is bent. In the ordinary Hall effect, the direction of motion of a charged particle moving in a magnetic field is bent by the Lorentz force. In contrast, in the spin Hall effect, the direction of spin movement is bent simply by the movement of electrons (simply by the flow of current), even without a magnetic field.

[0061] For example, when current flows in the x direction along the spin-orbit torque wiring 8, spin currents are generated in both the y and z directions. Due to these spin currents, spins polarized in the +y direction (e.g., + spins) are concentrated on the first surface of the spin-orbit torque wiring 8, and spins polarized in the opposite direction to the -y direction (e.g., - spins) are concentrated on the second surface opposite to the first surface. The spins accumulated on the first or second surface are injected into the adjacent first ferromagnetic layer 1.

[0062] The spin-orbit torque wiring 8 includes any of the following materials: metal, alloy, intermetallic compound, metal boride, metal carbide, metal silide, metal phosphide, or metal nitride, which have the function of generating a pure spin current by the spin Hall effect when an electric current flows through them.

[0063] The spin-orbit torque wiring 8 includes, for example, non-magnetic heavy metals. Here, heavy metals refer to metals with a specific gravity greater than or equal to yttrium. Non-magnetic heavy metals are, for example, non-magnetic metals with a large atomic number of 39 or higher that have d or f electrons in their outermost shell. These non-magnetic metals have a large spin-orbit interaction that produces the spin Hall effect. The spin-orbit torque wiring 8 includes, for example, Hf, Ta, and W.

[0064] When data is written to the magnetic element 101, current flows along the spin-orbit torque wiring 8. When current flows along the spin-orbit torque wiring 8, spin is injected into the first ferromagnetic layer 1, and a spin-orbit torque (SOT) is applied to the magnetization M1 of the first ferromagnetic layer 1. In other words, in the magnetic element 101, the magnetization M1 of the first ferromagnetic layer 1 is reversed by the voltage magnetic anisotropy control effect, spin transfer torque, and spin-orbit torque.

[0065] As described above, the magnetic element 101 according to the second embodiment controls the magnetization M1 of the first ferromagnetic layer 1 by utilizing three effects, thereby reducing the reversal current density required to reverse the magnetization M1 of the first ferromagnetic layer 1.

[0066] Furthermore, in SOT-type magnetoresistive elements, when the magnetization M1 of the first ferromagnetic layer 1 is oriented in the z direction, the application of an external magnetic field is required for stable magnetization reversal. In contrast, in the magnetic element 101 according to the second embodiment, the voltage magnetic anisotropy control effect and spin transfer torque assist the spin orbit torque, so the magnetization M1 can be reversed without applying an external magnetic field.

[0067] "Third Embodiment" Figure 7 is a cross-sectional view of the magnetic element 102 according to the third embodiment. Figure 7 is a cross-section obtained by cutting the magnetic element 102 through the xz plane passing through the center of its width in the y direction. The plan view of the magnetic element 102 is substantially the same as that of Figure 4. In the magnetic element 102, components similar to those in the magnetic element 101 are given the same reference numerals and their descriptions are omitted.

[0068] The spin-orbit torque wiring 8 of the magnetic element 102 comprises a third ferromagnetic layer 81, a fourth ferromagnetic layer 82, and a spacer layer 83. The spacer layer 83 is sandwiched between the third ferromagnetic layer 81 and the fourth ferromagnetic layer 82. The magnetization M81 of the third ferromagnetic layer 81 and the magnetization M82 of the fourth ferromagnetic layer 82 are oriented in one of the directions in the xy plane and are antiferromagnetically coupled.

[0069] The third ferromagnetic layer 81 and the fourth ferromagnetic layer 82 can be made from the same material as the first ferromagnetic layer 1. The spacer layer 83 can be made from the same material as the non-magnetic layer 3.

[0070] The third ferromagnetic layer 81 and the fourth ferromagnetic layer 82 tilt the magnetization M1 of the first ferromagnetic layer 1 in the in-plane direction through magnetic coupling. In addition, the first ferromagnetic layer 1 is subjected to voltage magnetic anisotropy control effect, spin transfer torque, and spin orbit torque. Therefore, the magnetic element 102 according to the third embodiment can reduce the reversal current density required to reverse the magnetization M1 of the first ferromagnetic layer 1.

[0071] "Fourth Embodiment" Figure 8 is a cross-sectional view of the magnetic element 103 according to the fourth embodiment. Figure 8 is a cross-section obtained by cutting the magnetic element 103 through the xz plane passing through the center of its width in the y direction. In the magnetic element 103, components similar to those in the magnetic element 101 are given the same reference numerals and their descriptions are omitted.

[0072] Magnetic element 103 differs from magnetic element 100 in that it further comprises a resistive layer 9 and a third electrode 10.

[0073] The resistive layer 9 is located between the gate insulating layer 4 and the second electrode 6 and the third electrode 10. The resistive layer 9 is another example of the conductive layer 7. The resistive layer 9 creates a potential difference between the second electrode 6 and the third electrode 10.

[0074] The resistive layer 9 is an oxide containing one or more elements selected from the group consisting of Ir, W, Pd, Mo, Nb, Re, Fe, Cr, V, Ti, Ru, Sn, In, Zr, and Cu. Examples of resistive layer 9 include IrO2, WO3, PdO2, MoO3, NbO, ReO3, FeO, Fe3O4, CrO2, VO2, V2O3, TiO, Ti2O3, RuO2, RuO3, SnO2, In2O3, TiO2, ZrO2, and CuO2. If the resistive layer 9 is a high-resistance material, a potential gradient can be created between the second electrode 6 and the third electrode 10.

[0075] The third electrode 10 is connected to the resistive layer 9 at a different position from the second electrode 6. The same material as that used for the first electrode 5 can be used for the third electrode 10.

[0076] The magnetic element 103 applies a potential difference between the second electrode 6 and the third electrode 10 during data writing, creating a potential gradient in the resistive layer 9. Figure 9 is a circuit diagram of the integrated circuit 203 according to the fourth embodiment. In Figure 9, components similar to those in the integrated circuit 200 and integrated circuit 200A are denoted by the same reference numerals and their descriptions are omitted. The voltage source 110 is connected to the first electrode 5, the second electrode 6, and the third electrode 10. The voltage source 110 controls the potential difference between the first electrode 5 and the second electrode 6 and the third electrode 10, and the potential difference between the second electrode 6 and the third electrode 10. Also, as shown in Figure 10, in the fourth embodiment, the voltage source 110 may be shared by multiple magnetic elements 103.

[0077] The potential gradient of the resistive layer 9 creates a potential gradient in the x-direction of the first ferromagnetic layer 1. When a potential gradient is generated in the x-direction of the first ferromagnetic layer 1, a voltage magnetic anisotropy control effect also occurs in the x-direction. That is, in the magnetic element 103, the magnetization M1 of the first ferromagnetic layer 1 is reversed by the voltage magnetic anisotropy control effect in the z-direction and x-direction and the spin transfer torque. Therefore, the magnetic element 103 according to the fourth embodiment can reduce the reversal current density required for the reversal of the magnetization M1 of the first ferromagnetic layer 1.

[0078] "Fifth Embodiment" Figure 11 is a cross-sectional view of the integrated device 204 according to the fifth embodiment. Figure 11 is a cross-section of the magnetic element 104 cut by the xz plane passing through the center of the width in the y direction. Figure 12 is a circuit diagram of the integrated device 204 according to the fifth embodiment. In the magnetic element 104, components similar to those in the magnetic element 100 are denoted by the same reference numerals and their descriptions are omitted.

[0079] The integrated device 204 has a plurality of magnetic elements 104. Adjacent magnetic elements 104 share a gate insulating layer 11 and a conductive layer 12. The gate insulating layer 11 is formed by connecting gate insulating layers 4 according to the first embodiment between two adjacent magnetic elements 104. The conductive layer 12 is formed by connecting conductive layers 12 according to the first embodiment between two adjacent magnetic elements 104.

[0080] Since the conductive layer 12 is connected to the integrated device 204, a voltage can be applied simultaneously to the second electrode 6 of multiple magnetic elements 104. The voltage source 110 can be shared by multiple magnetic elements 104. Even when a voltage is applied simultaneously to the second electrode 6 of multiple magnetic elements 104, the magnetic element 104 to be written to can be arbitrarily set by turning the first switching element Sw1 ON / OFF.

[0081] The integrated device 204 according to the fifth embodiment controls the magnetization M1 of the first ferromagnetic layer 1 by utilizing the voltage magnetic anisotropy control effect and the spin transfer torque, thereby achieving the same effects as the first embodiment. Furthermore, the first switching element Sw1 can be placed outside the integration region, thereby improving the integration efficiency of the integrated device 204.

[0082] "Sixth Embodiment" Figure 13 is a cross-sectional view of the integrated device 205 according to the sixth embodiment. Figure 13 is a cross-section obtained by cutting the magnetic element 105 through the xz plane passing through the center of the width in the y direction. Figure 14 is a circuit diagram of the integrated device 205 according to the sixth embodiment. In the magnetic element 105, components similar to those in the magnetic element 100 are denoted by the same reference numerals and their descriptions are omitted. In the integrated device 205, components similar to those in the integrated devices 200 and 200A are denoted by the same reference numerals and their descriptions are omitted.

[0083] The integrated device 205 has a plurality of magnetic elements 105. Adjacent magnetic elements 105 are electrically connected by a connecting portion 13. The connecting portion 13 electrically connects at least two first electrodes 5 of the plurality of magnetic elements 105 to each other, or between the first electrodes 5 and the second ferromagnetic layer 2. The connecting portion 13 is a conductor.

[0084] Since the magnetic elements 105 in the integrated device 204 are connected at the connection part 13, a write current can be applied to multiple magnetic elements 105 simultaneously. Even when a write current is applied to multiple magnetic elements 105 simultaneously, the magnetic elements 105 to be written to can be arbitrarily set by applying voltage from the voltage source 110. In the sixth embodiment as well, the gate insulating layer 4 and the conductive layer 12 may be shared between two adjacent magnetic elements 105.

[0085] The integrated device 205 according to the sixth embodiment controls the magnetization M1 of the first ferromagnetic layer 1 by utilizing the voltage magnetic anisotropy control effect and the spin transfer torque, thereby achieving the same effects as the first embodiment. Furthermore, the second switching element Sw2 can be placed outside the integration region, thereby improving the integration efficiency of the integrated device 205.

[0086] "Seventh Embodiment" Figure 15 is a cross-sectional view of the magnetic element 106 according to the seventh embodiment. Figure 15 shows a cross-section of the magnetic element 106 cut by the xz plane passing through the center in the y direction. In the magnetic element 106 according to the seventh embodiment, components similar to those of the magnetic element 100 are denoted by the same reference numerals and their descriptions are omitted.

[0087] The magnetic element 106 is stacked in the opposite order to the magnetic element 100. The second ferromagnetic layer 2 is closer to the substrate Sub than the first ferromagnetic layer 1. Such an element is called a bottom-pin structure. Because the second ferromagnetic layer 2, which requires magnetization stability, is located near the substrate Sub, the stability of the magnetization M2 of the second ferromagnetic layer 2 is increased. The magnetic element 106 according to the seventh embodiment controls the magnetization M1 of the first ferromagnetic layer 1 by utilizing the voltage magnetic anisotropy control effect and the spin transfer torque, thus achieving the same effects as the first embodiment.

[0088] While preferred embodiments of the present invention have been illustrated based on several embodiments, the present invention is not limited to these embodiments. For example, characteristic configurations in each embodiment may be applied to other embodiments. [Explanation of symbols]

[0089] 1...First ferromagnetic layer, 1A...First surface, 1B...Second surface, 2...Second ferromagnetic layer, 3...Non-magnetic layer, 4...Gate insulating layer, 5...First electrode, 6...Second electrode, 7...Conductive layer, 8...Spin orbit torque wiring, 9...Resistive layer, 10...Third electrode, 11...Gate insulating layer, 12...Conductive layer, 13...Connection part, 81...Third ferromagnetic layer, 82...Fourth ferromagnetic layer, 83...Spacer layer, 100, 101, 102, 103, 104, 105, 106...Magnetic elements, 200, 200A, 203, 203A, 204, 205...Integrated devices

Claims

1. It comprises a first ferromagnetic layer, a second ferromagnetic layer, a non-magnetic layer, a gate insulating layer, a first electrode, a second electrode, and spin-orbit torque wiring. The non-magnetic layer and the first electrode are connected to the first surface of the first ferromagnetic layer at different positions. The second ferromagnetic layer, together with the first ferromagnetic layer, sandwiches the non-magnetic layer. The second electrode is connected to the second surface of the first ferromagnetic layer opposite to the first surface, with the gate insulating layer in between. The spin-orbit torque wiring is a magnetic element located between the first ferromagnetic layer and the gate insulating layer.

2. The spin-orbit torque wiring comprises a third ferromagnetic layer, a fourth ferromagnetic layer, and a spacer layer sandwiched between the third ferromagnetic layer and the fourth ferromagnetic layer. The magnetization of the third ferromagnetic layer and the magnetization of the fourth ferromagnetic layer are oriented in any direction within the plane in which the layers extend. The magnetic element according to claim 1, wherein the third ferromagnetic layer and the fourth ferromagnetic layer are antiferromagnetically coupled.

3. The magnetic element according to claim 1 or 2, wherein the magnetization of the first ferromagnetic layer is oriented in the stacking direction.

4. comprising a first ferromagnetic layer, a second ferromagnetic layer, a non-magnetic layer, a gate insulating layer, a first electrode, and a second electrode, The non-magnetic layer and the first electrode are connected to the first surface of the first ferromagnetic layer at different positions. The second ferromagnetic layer, together with the first ferromagnetic layer, sandwiches the non-magnetic layer. The second electrode is connected to the second surface of the first ferromagnetic layer opposite to the first surface, with the gate insulating layer in between. It further comprises a resistive layer and a third electrode, The resistive layer is located between the gate insulating layer and the second electrode. A magnetic element wherein the third electrode is connected to the resistive layer at a position different from that of the second electrode.

5. The magnetic element according to claim 4, wherein the resistive layer is an oxide containing any one or more elements selected from the group consisting of Ir, W, Pd, Mo, Nb, Re, Fe, Cr, V, Ti, Ru, Sn, In, Zr, and Cu.

6. Equipped with multiple magnetic elements, An integrated device in which each of the plurality of magnetic elements is a magnetic element according to any one of claims 1 to 5.

7. comprising a plurality of magnetic elements, Each of the plurality of magnetic elements comprises a first ferromagnetic layer, a second ferromagnetic layer, a non-magnetic layer, a gate insulating layer, a first electrode, and a second electrode. The non-magnetic layer and the first electrode are connected to the first surface of the first ferromagnetic layer at different positions. The second ferromagnetic layer, together with the first ferromagnetic layer, sandwiches the non-magnetic layer. The second electrode is connected to the second surface of the first ferromagnetic layer opposite to the first surface, with the gate insulating layer in between. An integrated device in which at least two of the plurality of magnetic elements share the gate insulating layer.

8. comprising a plurality of magnetic elements, Each of the plurality of magnetic elements comprises a first ferromagnetic layer, a second ferromagnetic layer, a non-magnetic layer, a gate insulating layer, a first electrode, and a second electrode. The non-magnetic layer and the first electrode are connected to the first surface of the first ferromagnetic layer at different positions. The second ferromagnetic layer, together with the first ferromagnetic layer, sandwiches the non-magnetic layer. The second electrode is connected to the second surface of the first ferromagnetic layer opposite to the first surface, with the gate insulating layer in between. Further comprising a conductive layer, An integrated device wherein the conductive layer is located between the second electrode and the gate insulating layer and is connected to the second electrode of a different magnetic element.

9. comprising a plurality of magnetic elements, Each of the plurality of magnetic elements comprises a first ferromagnetic layer, a second ferromagnetic layer, a non-magnetic layer, a gate insulating layer, a first electrode, and a second electrode. The non-magnetic layer and the first electrode are connected to the first surface of the first ferromagnetic layer at different positions. The second ferromagnetic layer, together with the first ferromagnetic layer, sandwiches the non-magnetic layer. The second electrode is connected to the second surface of the first ferromagnetic layer opposite to the first surface, with the gate insulating layer in between. It further includes a connection part, The connection portion electrically connects at least two of the first electrodes of the plurality of magnetic elements, or between the first electrodes and the second ferromagnetic layer, in an integrated device.

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