Magnetization rotating element, magnetoresistive effect element, and magnetic memory

Abstract

The present invention provides a magnetization rotation element comprising a spin-orbit torque wire, a first ferromagnetic layer, a first columnar body, a second columnar body, and a first conductive layer. The first ferromagnetic layer faces at least a portion of the spin-orbit torque wire. The first conductive layer is in contact with the spin-orbit torque wire at a position that does not overlap the first ferromagnetic layer as viewed from a laminating direction. The first columnar body penetrates the spin-orbit torque wire and is in contact with the spin-orbit torque wire and the first conductive layer. The second columnar body is in contact with the spin-orbit torque wire at such a position that the second columnar body and the first columnar body sandwich the first ferromagnetic layer as viewed from the laminating direction.

Description

[Technical Field]

[0001] The present invention relates to a magnetization rotation element, a magnetoresistive element, and a magnetic memory. [Background technology]

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

[0003] MRAM is a memory device that integrates magnetoresistive elements. MRAM reads and writes data by utilizing the property that the resistance of a magnetoresistive element changes when the magnetization directions of the two ferromagnetic layers sandwiching a nonmagnetic layer in the magnetoresistive element change. The magnetization direction of the ferromagnetic layer is controlled, for example, by using a magnetic field generated by an electric current. Alternatively, the magnetization direction of the ferromagnetic layer can be controlled by using spin transfer torque (STT) generated by passing an electric current in the stacking direction of the magnetoresistive element.

[0004] When using STT to rewrite the magnetization direction of a ferromagnetic layer, a current is passed through the magnetoresistive element in the stacking direction, and the write current causes deterioration of the magnetoresistive element's characteristics.

[0005] In recent years, attention has been focused on methods that do not require current to flow in the stacking direction of a magnetoresistive element during writing (for example, Patent Document 1). One such method is a writing method that utilizes spin-orbit torque (SOT). SOT is induced by spin current generated by spin-orbit interaction or the Rashba effect at the interface of different materials. The current used to induce SOT in a magnetoresistive element flows in a direction that intersects with the stacking direction of the magnetoresistive element. In other words, there is no need to flow current in the stacking direction of the magnetoresistive element, and this is expected to extend the life of the magnetoresistive element. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2017-216286 Summary of the Invention [Problem to be solved by the invention]

[0007] In a magnetoresistive element using spin-orbit torque (SOT), the magnetization of the ferromagnetic layer is reversed when the current density of the write current flowing through the spin-orbit torque wiring exceeds a certain value. The current density of the write current at which the magnetization of the ferromagnetic layer is reversed is called the reversal current density. To obtain a sufficient reversal current density, the thickness of the spin-orbit torque wiring is often made thin. The write current to the spin-orbit torque wiring is supplied through a via wiring. With a thin spin-orbit torque wiring, it is difficult to ensure sufficient electrical contact between the via wiring and the spin-orbit torque wiring.

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide a magnetization rotation element, a magnetoresistive effect element, and a magnetic memory that can ensure sufficient electrical contact between via wiring and spin orbit torque wiring. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides the following means.

[0010] (1) A magnetization rotator according to a first aspect includes a spin orbit torque line, a first ferromagnetic layer, a first columnar body, a second columnar body, and a first conductive layer. The first ferromagnetic layer faces at least a portion of the spin orbit torque line. The first conductive layer contacts the spin orbit torque line at a position that does not overlap with the first ferromagnetic layer when viewed from the stacking direction. The first columnar body penetrates the spin orbit torque line. The first columnar body contacts the spin orbit torque line and the first conductive layer. The second columnar contacts the spin orbit torque line at a position that sandwiches the first ferromagnetic layer together with the first columnar body when viewed from the stacking direction.

[0011] (2) In the magnetization rotating element according to the above aspect, a part of the side wall of the first columnar body may be in contact with the first conductive layer over the entire periphery.

[0012] (3) In the magnetization rotating element according to the above aspect, a first end of the first columnar body in the stacking direction may be in contact with the first conductive layer.

[0013] (4) The magnetization rotating element according to the above aspect may further include a covering layer, which covers the surfaces of the first conductive layer other than the surface in contact with the spin orbit torque wiring.

[0014] (5) In the magnetization rotating element according to the above aspect, the coating layer may have a lower etching rate than the first conductive layer when subjected to ion milling under the same conditions.

[0015] (6) In the magnetization rotating element according to the above aspect, the coating layer may have a lower etching rate than the first conductive layer when subjected to reactive ion etching under the same conditions.

[0016] (7) In the magnetization rotating element according to the above aspect, the film thickness of the first conductive layer may be 5% or more of the height of a perpendicular line extending from a second end of the first columnar body to the spin-orbit torque wiring, the second end being an end of the first columnar body farther from the first conductive layer in the stacking direction.

[0017] (8) In the magnetization rotator element according to the above aspect, the film thickness of the first conductive layer may be 300% or less of the height of a perpendicular line extending from the second end of the first columnar body to the spin orbit torque wiring.

[0018] (9) In the magnetization rotating element according to the above aspect, the first conductive layer and the second columnar body may be in contact with the same surface of the spin orbit torque wiring. The first conductive layer and the second columnar body may have the same main component among their constituent elements.

[0019] (10) The magnetization rotating element according to the above aspect may further include a second conductive layer. The second conductive layer may be in contact with the spin orbit torque wire. A second columnar body may penetrate the spin orbit torque wire and be in contact with the spin orbit torque wire and the second conductive layer.

[0020] (11) A magnetoresistive element according to a second aspect may include at least the magnetization rotation element according to the above aspect, a non-magnetic layer, and a second ferromagnetic layer, wherein the non-magnetic layer is sandwiched between the first ferromagnetic layer and the second ferromagnetic layer of the magnetization rotation element.

[0021] (12) A magnetic memory according to a third aspect includes the magnetoresistive element according to the above aspect. [Effects of the Invention]

[0022] The magnetization rotation element, magnetoresistive element, and magnetic memory according to the present disclosure can ensure sufficient electrical contact between the via wiring and the spin orbit torque wiring. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a circuit diagram of a magnetic memory according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view of a characteristic portion of the magnetic memory according to the first embodiment. [Figure 3] FIG. 1 is a cross-sectional view of a magnetoresistive effect element according to a first embodiment. [Figure 4]FIG. 1 is a plan view of a magnetoresistive effect element according to a first embodiment. [Figure 5] FIG. 10 is a cross-sectional view of a magnetoresistive effect element according to a second embodiment. [Figure 6] FIG. 10 is a cross-sectional view of a magnetoresistive effect element according to a third embodiment. [Figure 7] FIG. 10 is a plan view of a magnetoresistive effect element according to a third embodiment. [Figure 8] FIG. 10 is a cross-sectional view of a magnetoresistive effect element according to a fourth embodiment. [Figure 9] FIG. 10 is a plan view of a magnetoresistive effect element according to a fourth embodiment. [Figure 10] FIG. 10 is a cross-sectional view of a magnetoresistive effect element according to a fifth embodiment. [Figure 11] FIG. 10 is a cross-sectional view of a magnetization rotating element according to a sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present embodiment will be described in detail below with reference to the drawings as appropriate. The drawings used in the following description may show characteristic portions enlarged for the sake of clarity, and the dimensional ratios of each component may differ from the actual ones. The materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited thereto. Appropriate changes can be made within the scope of the effects of the present invention.

[0025] First, directions are defined. One direction on one surface of the substrate Sub (see FIG. 2), which will be 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 longitudinal direction of the spin-orbit torque wiring 20. The z-direction is a direction perpendicular to the x-direction and the y-direction. The z-direction is an example of the stacking direction in which each layer is stacked. Hereinafter, 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 is applied.

[0026] As used herein, "extending in the x-direction" means, for example, that the dimension in the x-direction is greater than the smallest dimension among the dimensions in the x-, y-, and z-directions. The same applies to extending in other directions. Furthermore, "connection" as used herein is not limited to physical connection. For example, "connection" is not limited to when two layers are physically in contact with each other, but also includes when two layers are connected with another layer sandwiched between them. Furthermore, "connection" as used herein also includes electrical connection. Furthermore, "facing" as used herein means that two layers are in a facing relationship, and the two layers may be in contact with each other or may face each other with another layer sandwiched between them.

[0027] "First embodiment" 1 is a configuration diagram of a magnetic memory 200 according to a first embodiment. The magnetic memory 200 includes a plurality of magnetoresistive effect elements 100, a plurality of write lines WL, a plurality of common lines CL, a plurality of read lines RL, a plurality of first switching elements Sw1, a plurality of second switching elements Sw2, and a plurality of third switching elements Sw3. In the magnetic memory 200, for example, the magnetoresistive effect elements 100 are arranged in a matrix.

[0028] Each write wiring WL electrically connects a power supply to one or more magnetoresistive effect elements 100. Each common wiring CL is a wiring used both when writing and reading data. Each common wiring CL electrically connects a reference potential to one or more magnetoresistive effect elements 100. The reference potential is, for example, ground. The common wiring CL may be provided for each of the multiple magnetoresistive effect elements 100, or may be provided across the multiple magnetoresistive effect elements 100. Each read wiring RL electrically connects a power supply to one or more magnetoresistive effect elements 100. The power supply is connected to the magnetic memory 200 during use.

[0029] Each magnetoresistive element 100 is electrically connected to a first switching element Sw1, a second switching element Sw2, and a third switching element Sw3, respectively. The first switching element Sw1 is connected between the magnetoresistive element 100 and a write wiring WL. The second switching element Sw2 is connected between the magnetoresistive element 100 and a common wiring CL. The third switching element Sw3 is connected to a read wiring RL that spans the multiple magnetoresistive elements 100.

[0030] When predetermined first switching element Sw1 and second switching element Sw2 are turned ON, a write current flows between the write wiring WL and the common wiring CL connected to the predetermined magnetoresistive effect element 100. The flow of the write current writes data to the predetermined magnetoresistive effect element 100. When predetermined second switching element Sw2 and third switching element Sw3 are turned ON, a read current flows between the common wiring CL and the read wiring RL connected to the predetermined magnetoresistive effect element 100. The flow of the read current reads data from the predetermined magnetoresistive effect element 100.

[0031] 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 or an avalanche diode, or elements whose conductivity changes with a change in atomic position.

[0032] 1, the magnetoresistive effect elements 100 connected to the same read wiring RL share the third switching element Sw3. The third switching element Sw3 may be provided in each magnetoresistive effect element 100. Alternatively, the third switching element Sw3 may be provided in each magnetoresistive effect element 100, and the first switching element Sw1 or the second switching element Sw2 may be shared by the magnetoresistive effect elements 100 connected to the same wiring.

[0033] Fig. 2 is a cross-sectional view of a characteristic portion of the magnetic memory 200 according to the first embodiment. Fig. 2 is a cross-section of the magnetoresistive element 100 taken along an xz plane passing through the center of the width in the y direction of the spin orbit torque wiring 20, which will be described later.

[0034] The first switching element Sw1 and the second switching element Sw2 shown in Fig. 2 are transistors Tr. The third switching element Sw3 is electrically connected to the readout wiring RL and is located at a different position in the y direction in Fig. 2, for example. 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 a drain D formed on a substrate Sub. The source S and the drain D are determined by the direction of current flow and are in the same region. The positional relationship between the source S and the drain D may be reversed. The substrate Sub is, for example, a semiconductor substrate.

[0035] The transistor Tr and the magnetoresistive effect element 100 are electrically connected via a via wiring W1 and an in-plane wiring W2. The transistor Tr and the write wiring WL or the common wiring CL are connected by the via wiring W1. The via wiring W1 extends, for example, in the z direction. The via wiring W1 may be formed by stacking multiple pillars. The in-plane wiring W2 extends in any direction within the xy plane. The via wiring W1 and the in-plane wiring W2 contain a conductive material.

[0036] The magnetoresistive element 100 and the transistor Tr are covered with an insulating layer 90. The insulating layer 90 is an insulating layer that provides insulation between the wires in the multilayer wiring and between the elements. The insulating layer 90 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 (ZrO x ), magnesium oxide (MgO), aluminum nitride (AlN), etc.

[0037] Fig. 3 is a cross-sectional view of the magnetoresistive effect element 100. Fig. 3 is a cross-section of the magnetoresistive effect element 100 taken along the xz plane passing through the center of the y-direction width of the spin orbit torque wiring 20. Fig. 4 is a plan view of the magnetoresistive effect element 100 as viewed from the z direction.

[0038] The magnetoresistive element 100 includes, for example, a stack 10, a spin orbit torque wiring 20, a first columnar body 30, a second columnar body 40, and a first conductive layer 50. The periphery of the magnetoresistive element 100 is covered with insulating layers 91, 92, 93, and 94. The insulating layers 91, 92, 93, and 94 are stacked and are part of the insulating layer 90. The insulating layers 91, 92, 93, and 94 are each an interlayer insulating film stacked in layers.

[0039] The magnetoresistive element 100 is a magnetic element that utilizes spin orbit torque (SOT), and may be called a spin orbit torque type magnetoresistive element, a spin injection type magnetoresistive element, or a spin current magnetoresistive element.

[0040] The magnetoresistive element 100 is an element that records and stores data. The magnetoresistive element 100 records data as the resistance value in the z direction of the stack 10. The resistance value in the z direction of the stack 10 changes when a write current is applied along the spin orbit torque wiring 20 and spins are injected into the stack 10 from the spin orbit torque wiring 20. The resistance value in the z direction of the stack 10 can be read by applying a read current in the z direction of the stack 10.

[0041] The stack 10 is connected to the spin orbit torque wiring 20. The stack 10 is stacked on the spin orbit torque wiring 20, for example.

[0042] The laminate 10 is a columnar body. The planar shape of the laminate 10 in the z direction is, for example, a circle, an ellipse, or a rectangle. The side surface of the laminate 10 is, for example, inclined with respect to the z direction.

[0043] The stack 10 includes, for example, a first ferromagnetic layer 1, a second ferromagnetic layer 2, a non-magnetic layer 3, an underlayer 4, a cap layer 5, and a mask layer 6. The resistance value of the stack 10 changes depending on the difference in the relative angle between the magnetizations of the first ferromagnetic layer 1 and the second ferromagnetic layer 2, which sandwich the non-magnetic layer 3.

[0044] The first ferromagnetic layer 1 faces, for example, the spin orbit torque wiring 20. The first ferromagnetic layer 1 may be in direct contact with the spin orbit torque wiring 20, or indirect contact with the spin orbit torque wiring 20 via the underlayer 4. The first ferromagnetic layer 1 is stacked on, for example, the spin orbit torque wiring 20.

[0045] Spins are injected into the first ferromagnetic layer 1 from the spin orbit torque wiring 20. The magnetization of the first ferromagnetic layer 1 is subjected to spin orbit torque (SOT) by the injected spins, and the orientation direction of the magnetization changes. The first ferromagnetic layer 1 is called a magnetization free layer.

[0046] The first ferromagnetic layer 1 includes a ferromagnetic material, such as a metal selected from the group consisting of Cr, Mn, Co, Fe, and Ni, an alloy containing one or more of these metals, or an alloy containing one or more of these metals and at least one of B, C, and N. Examples of the ferromagnetic material include Co—Fe, Co—Fe—B, Ni—Fe, Co—Ho alloy, Sm—Fe alloy, Fe—Pt alloy, Co—Pt alloy, and CoCrPt alloy.

[0047] The first ferromagnetic layer 1 may include a Heusler alloy. The Heusler alloy includes 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 element or an element species of X of the Mn, V, Cr, or Ti group, and Z is a typical element of groups III to V. Examples of Heusler alloys include Co2FeSi, Co2FeGe, Co2FeGa, Co2MnSi, and Co2Mn 1-a Fe a Al b Si 1-b , Co2FeGe 1-c Ga c etc. Heusler alloys have high spin polarization.

[0048] The second ferromagnetic layer 2 faces the first ferromagnetic layer 1 with a nonmagnetic layer 3 sandwiched therebetween. The second ferromagnetic layer 2 includes a ferromagnetic material. The magnetization of the second ferromagnetic layer 2 is less likely to change orientation than the magnetization of the first ferromagnetic layer 1 when a predetermined external force is applied. The second ferromagnetic layer 2 is also called a magnetization fixed layer or a magnetization reference layer. The stack 10 shown in FIG. 3 has the magnetization fixed layer on the side farther from the substrate Sub, and is called a top-pin structure.

[0049] The second ferromagnetic layer 2 is made of the same material as the first ferromagnetic layer 1.

[0050] The second ferromagnetic layer 2 may have a synthetic antiferromagnetic structure (SAF structure). A synthetic antiferromagnetic structure consists of two magnetic layers sandwiching a nonmagnetic layer. The second ferromagnetic layer 2 may have two magnetic layers and a spacer layer sandwiched between them. Antiferromagnetic coupling between the two ferromagnetic layers increases the coercive force of the second ferromagnetic layer 2. The ferromagnetic layer may be, for example, IrMn or PtMn. The spacer layer may include, for example, at least one selected from the group consisting of Ru, Ir, and Rh.

[0051] The nonmagnetic layer 3 is sandwiched between the first ferromagnetic layer 1 and the second ferromagnetic layer 2. The nonmagnetic layer 3 includes a nonmagnetic material. When the nonmagnetic layer 3 is an insulator (a tunnel barrier layer), its material may be, for example, Al2O3, SiO2, MgO, or MgAl2O4. In addition to these, materials in which a portion of Al, Si, or Mg is substituted with Zn, Be, or the like may also be used. Among these, MgO and MgAl2O4 are materials that enable coherent tunneling, enabling efficient spin injection. When the nonmagnetic layer 3 is a metal, its material may be Cu, Au, Ag, or the like. Furthermore, when the nonmagnetic layer 3 is a semiconductor, its material may be Si, Ge, CuInSe2, CuGaSe2, Cu(In,Ga)Se2, or the like.

[0052] The underlayer 4 is, for example, between the first ferromagnetic layer 1 and the spin-orbit torque wiring 20. The underlayer 4 may be omitted.

[0053] The underlayer 4 includes, for example, a buffer layer and a seed layer. The buffer layer is a layer that alleviates lattice mismatch between different crystals. The seed layer improves the crystallinity of the layer stacked on the seed layer. The seed layer is formed, for example, on the buffer layer.

[0054] The buffer layer is made of, for example, Ta (element), TaN (tantalum nitride), CuN (copper nitride), TiN (titanium nitride), or NiAl (nickel aluminum).The seed layer is made of, for example, Pt, Ru, Zr, a NiCr alloy, or NiFeCr.

[0055] The cap layer 5 is on the second ferromagnetic layer 2. The cap layer 5, for example, strengthens the perpendicular magnetic anisotropy of the second ferromagnetic layer 2. The cap layer 5 is made of, for example, magnesium oxide, W, Ta, Mo, or the like. The thickness of the cap layer 5 is, for example, 0.5 nm or more and 5.0 nm or less.

[0056] The mask layer 6 is on the cap layer 5. The mask layer 6 is part of a hard mask used when processing the stack 10 during manufacturing. The mask layer 6 also functions as an electrode. The mask layer 6 includes, for example, Al, Cu, Ta, Ti, Zr, NiCr, nitrides (e.g., TiN, TaN, SiN), and oxides (e.g., SiO2).

[0057] The stack 10 may include layers other than the first ferromagnetic layer 1, the second ferromagnetic layer 2, the non-magnetic layer 3, the underlayer 4, the cap layer 5, and the mask layer 6.

[0058] For example, the spin orbit torque wire 20 extends in the x direction, with its length in the x direction being longer than its length in the y direction when viewed from the z direction. A write current flows in the x direction along the spin orbit torque wire 20 between the first columnar body 30 and the second columnar body 40.

[0059] The spin-orbit torque wiring 20 generates a spin current by the spin Hall effect when a current flows, and injects spin into the first ferromagnetic layer 1. The spin-orbit torque wiring 20 applies a spin-orbit torque (SOT) to the magnetization of the first ferromagnetic layer 1 that is sufficient to reverse the magnetization of the first ferromagnetic layer 1, for example.

[0060] The spin Hall effect is a phenomenon in which, when an electric current is passed through it, a spin current is induced in a direction perpendicular to the direction of the electric current due to the spin-orbit interaction. The spin Hall effect is similar to the standard Hall effect in that the direction of movement of moving charges (electrons) is bent. In the standard Hall effect, the direction of movement of charged particles moving in a magnetic field is bent by the Lorentz force. In contrast, in the spin Hall effect, the direction of spin movement can be bent simply by moving electrons (current flow) even in the absence of a magnetic field.

[0061] For example, when a current flows through the spin-orbit torque wiring 20, the first spin polarized in one direction and the second spin polarized in the opposite direction to the first spin are bent by the spin Hall effect in a direction perpendicular to the direction of the current flow. For example, the first spin polarized in the -y direction is bent from the x direction, which is the direction of travel, to the +z direction, and the second spin polarized in the +y direction is bent from the x direction, which is the direction of travel, to the -z direction.

[0062] In non-magnetic materials (materials that are not ferromagnetic), the number of electrons with the first spin, which is generated by the spin Hall effect, is equal to the number of electrons with the second spin. In other words, the number of electrons with the first spin in the +z direction is equal to the number of electrons with the second spin in the -z direction. The first and second spins flow in a direction that eliminates the spin imbalance. When the first and second spins move in the z direction, the flow of charge cancels each other out, so the amount of current is zero. Spin current that does not involve current is specifically called pure spin current.

[0063] The flow of electrons with the first spin is called J ↑ , the flow of electrons of the second spin is J ↓ , the spin current is J S Then, J S =J ↑ -J ↓ The spin current J is defined as S is generated in the z direction. The first spin is injected into the first ferromagnetic layer 1 from the spin orbit torque wiring 20.

[0064] The spin-orbit torque wiring 20 includes any one of a metal, alloy, intermetallic compound, metal boride, metal carbide, metal silicide, metal phosphide, and metal nitride, which has the function of generating a spin current by the spin Hall effect when a write current flows. The spin-orbit torque wiring 20 includes, for example, any one selected from the group consisting of heavy metals with atomic numbers of 39 or more, metal oxides, metal nitrides, metal oxynitrides, and topological insulators.

[0065] The spin orbit torque wiring 20 contains, for example, a non-magnetic heavy metal as a main component. Heavy metal means a metal with a specific gravity equal to or greater than that of yttrium (Y). Non-magnetic heavy metals are, for example, non-magnetic metals with a high atomic number of 39 or greater that have d electrons or f electrons in their outermost shells. The spin orbit torque wiring 20 is made of, for example, Hf, Ta, or W. Non-magnetic heavy metals generate stronger spin orbit interactions than other metals. The spin Hall effect is generated by spin orbit interactions, and spins tend to be unevenly distributed within the spin orbit torque wiring 20, resulting in a spin current J. S is more likely to occur.

[0066] The spin orbit torque wiring 20 may also contain a magnetic metal. The magnetic metal is a ferromagnetic metal or an antiferromagnetic metal. A trace amount of magnetic metal contained in a non-magnetic material acts as a scattering factor for spin. A trace amount is, for example, 3% or less of the total molar ratio of the elements constituting the spin orbit torque wiring 20. When spins are scattered by the magnetic metal, the spin orbit interaction is strengthened, and the efficiency of generating a spin current relative to an electric current increases.

[0067] The spin-orbit torque wiring 20 may include a topological insulator. A topological insulator is a material whose interior is insulating or highly resistive, but whose surface exhibits a spin-polarized metallic state. In a topological insulator, an internal magnetic field is generated due to spin-orbit interaction. In a topological insulator, a new topological phase emerges due to the effect of spin-orbit interaction, even in the absence of an external magnetic field. A topological insulator can generate pure spin currents with high efficiency due to the strong spin-orbit interaction and the breaking of inversion symmetry at the edges.

[0068] Topological insulators include, for example, 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 are capable of generating spin current with high efficiency.

[0069] The spin-orbit torque wiring 20 is not limited to a single layer, but may be a laminate of multiple layers. The spin-orbit torque wiring 20 may have, for example, multiple heavy metal layers and an insertion layer sandwiched between them.

[0070] The electrical resistivity of the spin orbit torque wire 20 is, for example, 1 mΩ·cm or more. Also, the electrical resistivity of the spin orbit torque wire 20 is, for example, 10 mΩ·cm or less. If the electrical resistivity of the spin orbit torque wire 20 is high, a high voltage can be applied to the spin orbit torque wire 20. If the potential of the spin orbit torque wire 20 is high, spin can be efficiently supplied from the spin orbit torque wire 20 to the first ferromagnetic layer 1. Also, if the spin orbit torque wire 20 has a certain level of conductivity or more, a current path that flows along the spin orbit torque wire 20 can be secured, and a spin current associated with the spin Hall effect can be efficiently generated.

[0071] The thickness of the spin orbit torque wire 20 is, for example, 4 nm or more. The thickness of the spin orbit torque wire 20 may be, for example, 20 nm or less.

[0072] The first pillar 30 is a part of the via wire W1. The first pillar 30 is the pillar of one via wire W1 that is closest to the spin-orbit torque wire 20. The pillar is, for example, a circular cylinder, an elliptical cylinder, or a rectangular pillar. A pillar is defined as a region of the via wire W1 where the perimeter is either continuously changing or constant. The pillar is formed by filling an opening formed in a single processing step during manufacturing with a conductor.

[0073] The first pillar 30 penetrates the spin orbit torque line 20. The first pillar 30 contacts the spin orbit torque line 20 and the first conductive layer 50.

[0074] The first columnar body 30 has, for example, a first region 31. The first region 31 is a portion of the first columnar body 30 that protrudes from the first surface 20A of the spin orbit torque wire 20. The first surface 20A is a surface of the spin orbit torque wire 20 that comes into contact with the first conductive layer 50.

[0075] The first region 31 is surrounded by the first conductive layer 50. In the first region 31, the sidewall of the first columnar body 30 contacts the first conductive layer 50 over the entire periphery. The first end 30A of the first columnar body 30 contacts the first conductive layer 50. The first end 30A is the end closest to the first conductive layer 50 in the z direction.

[0076] First columns 30 include a conductive material such as aluminum, copper, or silver.

[0077] Second columnar body 40 is a part of via wiring W1. Second columnar body 40 is the columnar body closest to spin-orbit torque wiring 20 in via wiring W1 that is different from via wiring W1 that includes first columnar body 30.

[0078] When viewed from the z direction, the second columnar body 40 contacts the spin orbit torque wiring 20 at a position where it and the first columnar body 30 sandwich the first ferromagnetic layer 1. The first columnar body 30 and the second columnar body 40 are connected to the spin orbit torque wiring 20 at different positions in the x direction. When viewed from the z direction, a stacked body is present between the first columnar body 30 and the second columnar body 40 in the x direction.

[0079] Second columnar body 40 contacts, for example, first surface 20A, which contacts first conductive layer 50. For example, the z-direction center point of first columnar body 30 and the z-direction center point of second columnar body 40 are positioned in a positional relationship in the z direction such that they sandwich a reference plane on which spin-orbit torque wiring 20 extends. Second columnar body 40 may contact second surface 20B, which faces first surface 20A.

[0080] Second columns 40 include a conductive material such as aluminum, copper, or silver.

[0081] The thickness t of the second columnar body 40 40 is, for example, the film thickness t 50 matches.

[0082] The first conductive layer 50 is in contact with the spin orbit torque wiring 20. The first conductive layer 50 is in contact with the spin orbit torque wiring 20 at a position that does not overlap with the first ferromagnetic layer 1, for example, when viewed from the z direction. The first conductive layer 50 overlaps with the first columnar body 30, for example, when viewed from the z direction.

[0083] The width W of the first conductive layer 50 in the y direction 50y is, for example, the width W in the y direction of the spin-orbit torque wiring 20 20y The width W of the first conductive layer 50 in the y direction is wider. 50y is, for example, the width W of the first columnar body 30 in the y direction 30y The width W of the spin-orbit torque wiring 20 in the y direction is 20y is, for example, the width W of the first columnar body 30 in the y direction 30y The width W of the first columnar body 30 in the y direction is 30y is, for example, the width of the first columnar body 30 in the y direction at the surface that contacts the second surface 20B of the spin orbit torque wiring 20.

[0084] The width W of the first conductive layer 50 in the x direction 50x is the width W of the first columnar body 30 in the x direction 30x The width W of the first columnar body 30 in the x direction is 30x is the width of the first columnar body 30 in the x direction at the surface that contacts the second surface 20B of the spin orbit torque wiring 20.

[0085] Width W of the first conductive layer 50 50x , W 50y If the opening is sufficiently wide, electrical conduction between the first columnar body 30 and the first conductive layer 50 can be sufficiently ensured even if the opening is misaligned during fabrication of the first columnar body 30 .

[0086] The thickness t of the first conductive layer 50 50 is, for example, 5% or more of the height L1 of the perpendicular line extending from the second end 30B of the first columnar body 30 to the second surface 20B of the spin orbit torque wiring 20. 50is, for example, 300% or less of the height L1 of a perpendicular line extending from the second end 30B of the first columnar body 30 to the second surface 20B of the spin orbit torque wiring 20. The first columnar body 30 is fabricated by filling an opening formed in the insulating layer 94 with a conductor. The height L1 of a perpendicular line extending from the second end 30B to the second surface 20B is equal to the depth of the opening. The film thickness t of the first conductive layer 50 50 If is in the above range, it is possible to prevent the opening from penetrating through the first conductive layer 50 when the opening is formed.

[0087] Second end 30B is the end of first columnar body 30 opposite first end 30A. Second end 30B is the end of first columnar body 30 farther from first conductive layer 50 in the z direction. Second surface 20B is the surface opposite first surface 20A that contacts first conductive layer 50.

[0088] The thickness t of the first conductive layer 50 50 is, for example, the height t of the laminate 10 10 The thickness t of the first conductive layer 50 is 5% or more. 50 is, for example, the height t of the laminate 10 10 The thickness t of the first conductive layer 50 is 300% or less. 50 may be approximately equal to the height L1 of a perpendicular line drawn from the second end 30B to the second surface 20B.

[0089] The first conductive layer 50 includes a conductive material, such as aluminum, copper, or silver.

[0090] The first conductive layer 50 may be made of the same material as the spin orbit torque line 20. When the first conductive layer 50 and the spin orbit torque line 20 are made of the same material, the first conductive layer 50 is the part that protrudes from the plane where the first surface 20A of the spin orbit torque line 20 extends at the position where it overlaps with the stack 10 in the z direction.

[0091] Furthermore, when the first conductive layer 50 and the second columnar body 40 contact the same surface of the spin orbit torque wiring 20, the first conductive layer 50 and the second columnar body 40 may have the same main component among their constituent elements. The main component is an element that accounts for 80% or more of the composition.

[0092] Next, a method for manufacturing the magnetoresistive effect element 100 will be described. The magnetoresistive effect element 100 is formed by a process of stacking each layer and a process of processing a part of each layer into a predetermined shape. The layers can be stacked by sputtering, chemical vapor deposition (CVD), electron beam evaporation (EB evaporation), atomic laser deposition, or the like. The layers can be processed by photolithography, or the like.

[0093] First, an insulating layer 92 is formed on an insulating layer 91. Then, openings are formed in predetermined positions of the insulating layer 92. Next, a conductive layer is formed, and the openings are filled with a conductor. The conductor filled in the openings becomes the first conductive layer 50 and the second columnar bodies 40. Next, the top surfaces of the insulating layer 92, the first conductive layer 50, and the second columnar bodies 40 are polished by chemical mechanical polishing (CMP).

[0094] Next, the layers that will become the spin orbit torque wiring 20 and the layers that will become the stack 10 are deposited on one surface of the insulating layer 92, the first conductive layer 50, and the second columnar body 40. First, the stacked layers are processed into a predetermined shape to obtain the spin orbit torque wiring 20. Then, the periphery of each processed layer is covered with an insulating layer 93. Next, the layers that will become the stack 10 and the insulating layer 93 are processed into a predetermined shape to obtain the stack 10. Then, the periphery of the stack 10 is covered with an insulating layer 94.

[0095] The order of processing the spin orbit torque wiring 20 and the stack 10 may be reversed. For example, first, each layer that will become the stack 10 may be processed into the shape of the stack 10, and the periphery may be covered with the insulating layer 94. After that, the insulating layer 94 and the layer that will become the spin orbit torque wiring 20 may be processed into the shape of the spin orbit torque wiring 20, and the periphery may be covered with the insulating layer 93.

[0096] Next, an opening is formed in the insulating layer 94 at a position that overlaps with the first conductive layer 50 when viewed from the z direction. The opening is formed from the upper surface of the insulating layer 94 to the first conductive layer 50. The opening is then filled with a conductor, thereby obtaining the first columnar body 30.

[0097] In the magnetoresistive element 100 in accordance with the first embodiment, electrical contact between the first columnar body 30 and the spin orbit torque wiring 20 can be sufficiently ensured.

[0098] Without the first conductive layer 50, the first columnar body 30 and the spin orbit torque line 20 contact each other at the side surface of the first columnar body 30. Because the spin orbit torque line 20 is thin, it is difficult to ensure sufficient contact between the first columnar body 30 and the spin orbit torque line 20. If there are few contact points between the first columnar body 30 and the spin orbit torque line 20, a write current cannot be stably supplied to the spin orbit torque line 20, and the reproducibility of the magnetization reversal of the first ferromagnetic layer 1 decreases. In other words, the reliability of the magnetoresistive element 100 decreases.

[0099] In contrast to this, the magnetoresistive element 100 according to the first embodiment has the first conductive layer 50, and therefore it is also possible to pass a write current to the spin orbit torque wiring 20 via the first conductive layer 50. By ensuring a sufficient current path for the write current to reach the spin orbit torque wiring 20, it is possible to stabilize the magnetization reversal of the first ferromagnetic layer 1.

[0100] "Second embodiment" 5 is a cross-sectional view of the magnetoresistive effect element 101 according to the second embodiment. The magnetoresistive effect element 101 according to the second embodiment differs from the magnetoresistive effect element 100 according to the first embodiment in that it further includes a covering layer 51. In the magnetoresistive effect element 101 according to the second embodiment, the same components as those in the magnetoresistive effect element 100 are denoted by the same reference numerals, and description thereof will be omitted.

[0101] The covering layer 51 covers the surfaces of the first conductive layer 50 other than the surface in contact with the first surface 20A of the spin orbit torque wiring 20. The covering layer 51 is, for example, an oxide or a nitride. The covering layer 51 is preferably conductive.

[0102] For example, coating layer 51 may have a lower etching rate than first conductive layer 50 under the same ion milling conditions. That is, coating layer 51 may be less susceptible to etching than first conductive layer 50 under the same ion milling conditions. If coating layer 51 is less susceptible to etching by ion milling, coating layer 51 functions as a stopper when forming openings that will become first columnar bodies 30.

[0103] Furthermore, coating layer 51 may have a lower etching rate than first conductive layer 50 in reactive ion etching under the same conditions. That is, coating layer 51 may be more difficult to etch than first conductive layer 50 in reactive ion etching under the same conditions. If coating layer 51 is more difficult to etch by reactive ion etching, coating layer 51 functions as a stopper when forming openings that will become first columnar bodies 30.

[0104] The coating layer 51 may be, for example, Ti-N, Ta-N, Si-N, Si-O, MgO, Ta, or Ru. Here, Si-O may be a compound of Si and O, and the composition ratio of each component is not important. For example, SiO2, SiO3O4, and compounds that deviate from the stoichiometric composition are included in Si-O. The same applies to Ti-N, Ta-N, and Si-N.

[0105] The magnetoresistive effect element 101 according to the second embodiment has the same effects as the magnetoresistive effect element 100 according to the first embodiment. Furthermore, the magnetoresistive effect element 101 according to the second embodiment allows stable formation of openings that will become first columns 30.

[0106] "Third embodiment" Fig. 6 is a cross-sectional view of the magnetoresistive effect element 102 according to the third embodiment. Fig. 7 is a plan view of the magnetoresistive effect element 102 according to the third embodiment. The magnetoresistive effect element 102 according to the third embodiment differs from the magnetoresistive effect element 100 according to the first embodiment in that it further includes a second conductive layer 60. In the magnetoresistive effect element 102 according to the third embodiment, the same components as those in the magnetoresistive effect element 100 are denoted by the same reference numerals and will not be described again.

[0107] The second pillar 40 penetrates the spin orbit torque line 20. The second pillar 40 contacts the spin orbit torque line 20 and the second conductive layer 60.

[0108] The second columnar body 40 has, for example, a first region 41. The first region 41 is a portion of the second columnar body 40 that protrudes from the spin orbit torque wiring 20 toward the second conductive layer 60 side.

[0109] The first region 41 is surrounded by the second conductive layer 60. In the first region 41, the sidewall of the second columnar body 40 contacts the second conductive layer 60 along the entire periphery. The first end 40A of the second columnar body 40 contacts the second conductive layer 60. The first end 40A is the end closest to the second conductive layer 60 in the z direction.

[0110] The second conductive layer 60 is in contact with the spin orbit torque wiring 20. The second conductive layer 60 is in contact with the spin orbit torque wiring 20 at a position that does not overlap with the first ferromagnetic layer 1, for example, when viewed from the z direction. The second conductive layer 60 overlaps with the second columnar body 40, for example, when viewed from the z direction.

[0111] The width W of the second conductive layer 60 in the y direction 60y is the width W of the spin-orbit torque wiring 20 in the y direction 20y The width W of the second conductive layer 60 in the y direction is wider. 60y is the width W of the second columnar body 40 in the y direction 40y The width W of the second conductive layer 60 in the x direction is wider. 60x is the width W of the second columnar body 40 in the x direction 40x Wider.

[0112] The second conductive layer 60 includes a material having electrical conductivity. The second conductive layer 60 is made of, for example, aluminum, copper, silver, etc. The second conductive layer 60 may be made of the same material as the spin-orbit torque wiring 20.

[0113] The magnetoresistive effect element 102 according to the third embodiment has the same effects as the magnetoresistive effect element 100 according to the first embodiment. Furthermore, the magnetoresistive effect element 102 according to the third embodiment can also ensure sufficient electrical contact between the second columnar body 40 and the spin orbit torque wiring 20.

[0114] "Fourth embodiment" Fig. 8 is a cross-sectional view of the magnetoresistive effect element 103 according to the fourth embodiment. Fig. 9 is a plan view of the magnetoresistive effect element 103 according to the fourth embodiment. The magnetoresistive effect element 103 according to the fourth embodiment differs from the magnetoresistive effect element 100 according to the first embodiment in the positional relationship of the first columnar body 30 with respect to the spin orbit torque wiring 20 and the first conductive layer 50. In the magnetoresistive effect element 103 according to the fourth embodiment, the same components as those in the magnetoresistive effect element 100 are denoted by the same reference numerals, and description thereof will be omitted.

[0115] The first pillar 30 penetrates the spin orbit torque line 20. The first pillar 30 contacts the spin orbit torque line 20 and the first conductive layer 50.

[0116] When viewed from the z direction, a part of the first columnar body 30 protrudes in the x direction from the x direction end of the spin orbit torque wiring 20. A part of the sidewall of the first region 31 of the first columnar body 30 contacts the first conductive layer 50. A part of the first end 30A of the first columnar body 30 contacts the first conductive layer 50.

[0117] The magnetoresistive element 103 according to the fourth embodiment has the same effects as the magnetoresistive element 100 according to the first embodiment.

[0118] "Fifth embodiment" 10 is a cross-sectional view of a magnetoresistive effect element 104 according to the fifth embodiment. The magnetoresistive effect element 104 according to the fifth embodiment differs from the magnetoresistive effect element 102 according to the third embodiment in the direction in which the second columns 40 extend. In the magnetoresistive effect element 104 according to the fifth embodiment, the same components as those in the magnetoresistive effect element 102 are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0119] The second columnar body 40 penetrates the spin orbit torque wire 20. The second columnar body 40 contacts the spin orbit torque wire 20 and the second conductive layer 60. The second columnar body 40 extends in the same direction as the first columnar body 30, based on the plane on which the spin orbit torque wire 20 extends. The midpoint of the second columnar body 40 in the z direction and the midpoint of the first columnar body 30 in the z direction are both on the same side of the plane on which the spin orbit torque wire 20 extends.

[0120] The second conductive layer 60 contacts the first surface 20A, which is the same surface as the first conductive layer 50 of the spin orbit torque wiring 20 contacts.

[0121] The height of the second columnar body 40 is, for example, approximately equal to the height of the first columnar body 30. The thickness t 60 is the film thickness t of the first conductive layer 50 50 Approximately equals.

[0122] The magnetoresistive element 104 according to the fifth embodiment has the same effects as the magnetoresistive element 100 according to the first embodiment.

[0123] "Sixth embodiment" 11 is a cross-sectional view of a magnetization rotation element 110 according to the sixth embodiment. In FIG. 11, the magnetization rotation element 110 replaces the magnetoresistive effect element 100 according to the first embodiment. The magnetization rotation element 110 differs from the magnetoresistive effect element 100 in that it does not have the second ferromagnetic layer 2 or the non-magnetic layer 3.

[0124] The magnetization rotation element 110, for example, irradiates light onto the first ferromagnetic layer 1 and evaluates the light reflected by the first ferromagnetic layer 1. When the orientation direction of magnetization changes due to the magnetic Kerr effect, the polarization state of the reflected light changes. The magnetization rotation element 110 can be used, for example, as an optical element for an image display device or the like that utilizes the difference in the polarization state of light.

[0125] In addition, the magnetization rotating element 110 can be used alone as an anisotropic magnetic sensor, an optical element using the magnetic Faraday effect, or the like.

[0126] The magnetization rotator element 110 according to the sixth embodiment is the magnetoresistive element 100 without the non-magnetic layer 3 and the second ferromagnetic layer 2, and provides the same effects as the magnetoresistive element 100 according to the first embodiment.

[0127] Although several embodiments have been given so far to illustrate preferred aspects of the present invention, the present invention is not limited to these embodiments. For example, the characteristic configurations of each embodiment may be applied to other embodiments and modified examples. [Explanation of symbols]

[0128] 1...first ferromagnetic layer, 2...second ferromagnetic layer, 3...non-magnetic layer, 4...underlayer, 5...cap layer, 6...mask layer, 10...laminated body, 20...spin-orbit torque wiring, 20A...first surface, 20B...second surface, 30...first columnar body, 30A, 40A...first end, 30B, 40B...second end, 31, 41...first region, 40...second columnar body, 50...first conductive layer, 51...covering layer, 60...second conductive layer, 90, 91, 92, 93, 94...insulating layer, 100, 101, 102, 103, 104...magnetoresistive effect element, 110...magnetization rotation element, 200...magnetic memory

Claims

1. a spin-orbit torque wiring, a first ferromagnetic layer, a first columnar body, a second columnar body, and a first conductive layer; the first ferromagnetic layer faces at least a part of the spin-orbit torque wiring; the first conductive layer is in contact with the spin-orbit torque wiring at a position not overlapping with the first ferromagnetic layer when viewed from the stacking direction; a first columnar body that penetrates the spin-orbit torque line and is in contact with the spin-orbit torque line and the first conductive layer; the second columnar body contacts the spin orbit torque wiring at a position where the second columnar body sandwiches the first ferromagnetic layer together with the first columnar body when viewed from the stacking direction.

2. The magnetization rotating element according to claim 1 , wherein a part of the sidewall of the first columnar body is in contact with the first conductive layer over the entire periphery.

3. The magnetization rotation element according to claim 1 , wherein a first end of the first columnar body in the stacking direction is in contact with the first conductive layer.

4. Further comprising a coating layer, The magnetization rotating element according to claim 1 , wherein the covering layer covers a surface of the first conductive layer other than a surface in contact with the spin orbit torque wiring.

5. The magnetization rotating element according to claim 4 , wherein the covering layer has a lower etching rate than the first conductive layer when subjected to ion milling under the same conditions.

6. The magnetization rotating element according to claim 4 , wherein the covering layer has a lower etching rate than the first conductive layer when subjected to reactive ion etching under the same conditions.

7. a film thickness of the first conductive layer is 5% or more of the height of a perpendicular line extending from the second end of the first columnar body to the spin-orbit torque wiring; The magnetization rotation element according to claim 1 , wherein the second end is an end of the first columnar body farther from the first conductive layer in the stacking direction.

8. a film thickness of the first conductive layer is 300% or less of the height of a perpendicular line extending from the second end of the first columnar body to the spin-orbit torque wiring; The magnetization rotation element according to claim 1 , wherein the second end is an end of the first columnar body farther from the first conductive layer in the stacking direction.

9. the first conductive layer and the second columnar body are in contact with the same surface of the spin-orbit torque wiring, 2. The magnetization rotating element according to claim 1, wherein the first conductive layer and the second columnar body have the same main component among constituent elements.

10. Further comprising a second conductive layer; the second conductive layer is in contact with the spin-orbit torque wiring; The magnetization rotating element according to claim 1 , wherein the second columnar body penetrates the spin orbit torque wire and contacts the spin orbit torque wire and the second conductive layer.

11. A magnetic recording medium comprising at least the magnetization rotation element according to claim 1, a non-magnetic layer, and a second ferromagnetic layer, The magnetoresistive element is configured such that the first ferromagnetic layer and the second ferromagnetic layer of the magnetization rotation element sandwich the non-magnetic layer.

12. A magnetic memory comprising the magnetoresistive element according to claim 11.

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