JP2022073039A - Spin element, magnetic array and method for manufacturing spin element - Google Patents

Abstract

To provide a spin element with high operating efficiency, a magnetic array, and a method for manufacturing the spin element.SOLUTION: A spin element has a wiring extending in the first direction, a laminate stacked on the wiring and including a first ferromagnetic layer, and readout wiring stacked on the laminate and extending in the second direction that intersects the first direction, and the width in the first direction of the first side of the readout wiring on the laminate side is less than the width in the first direction of the second side of the readout wiring side of the laminate.SELECTED DRAWING: Figure 3

Description

The present invention relates to a spin device, a magnetic array, and a method for manufacturing a spin device.

Next-generation non-volatile memory is attracting attention as an alternative to flash memory, etc., whose miniaturization has reached its limit. For example, MRAM (Magnetoresistive Random Access Memory), ReRAM (Resistance Random Access Memory), PCRAM (Phase Change Random Access Memory), and the like are known as next-generation non-volatile memory.

The MRAM is a memory element using a magnetoresistive effect element. The resistance value of the magnetoresistive element changes depending on the difference in the relative angles of the magnetization directions of the two magnetic films. The MRAM records the resistance value of the magnetoresistive element as data.

Among spin elements that utilize changes in magnetic resistance, spin-orbit torque type magnetic resistance effect elements that utilize spin-orbit torque (SOT) (for example, Patent Document 1) and magnetic wall moving magnetic recording elements that utilize domain wall movement (for example, Patent Document 1). For example, patent document 2) is attracting attention. These spin elements are controlled by being connected to a semiconductor element such as a transistor by wiring.

Japanese Unexamined Patent Publication No. 2017-11258 Japanese Patent No. 5441005

The wiring used for the spin element may be limited in material. For example, in the case of a spin-orbit torque type magnetoresistive element, heavy metal is often used for wiring in order to inject a large amount of spin into the ferromagnetic layer. Further, for example, in the case of a magnetic domain wall moving type magnetic recording element, the wiring needs to be a magnetic film. These wirings are likely to be a source of heat because the materials that can be used are limited. On the other hand, in order to efficiently exhaust the heat generated by these wirings, if other wirings or the like are brought close to each other, capacitance may be generated between the wirings, a part of the writing current may leak, and the writing efficiency may decrease. be.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a spin element, a magnetic array, and a method for manufacturing a spin element having high operating efficiency.

The present invention provides the following means for solving the above problems.

(1) The spin element according to the first aspect is laminated on the wiring extending in the first direction, the wiring, the laminated body including the first ferromagnetic layer, and the laminated body, and the first. The read wiring extending in the second direction intersecting the direction is provided, and the width of the first surface of the read wiring on the laminate side is the width of the first surface of the laminate on the read wiring side. It is less than or equal to the width in the first direction.

(2) In the spin element according to the above aspect, the side wall of the laminated body and the side wall of the read wiring may be continuous.

(3) The spin element according to the above aspect further includes a first conductive layer and a second conductive layer connected to the wiring, and the first conductive layer and the second conductive layer are viewed from the stacking direction. The distance between the first conductive layer and the laminated body in the first direction may be shorter than the thickness of the laminated body in the laminated direction.

(4) In the spin element according to the above aspect, the read wiring may be narrowed at a position overlapping the laminated body when viewed from the stacking direction.

(5) The spin element according to the above aspect further includes a first conductive layer and a second conductive layer connected to the wiring, and the first conductive layer and the second conductive layer are viewed from the stacking direction. The width of the laminated body in the first direction may be wider than the distance between the first conductive layer and the laminated body in the first direction so as to sandwich the laminated body.

(6) The spin element according to the above aspect further includes an insulating layer in contact with the side wall of the laminated body and the side wall of the read wiring, and the insulating layer may be AlN or MgO.

(7) The spin element according to the above aspect further includes a write wiring and a common wiring connected to the wiring, and at least one of the write wiring and the common wiring is the read wiring when viewed from the stacking direction. May have a portion that overlaps with.

(8) In the spin element according to the above aspect, the read wiring may have a portion in which the width in the first direction is narrower than the first surface and the second surface facing the first surface.

(9) In the spin element according to the above aspect, the thickness of the read wiring in the stacking direction may be narrower than the width of the read wiring in the first direction.

(10) In the spin element according to the above aspect, the side wall of the laminated body and the side wall of the read wiring may be inclined with respect to the stacking direction.

(11) In the spin element according to the above aspect, the laminated body may have the first ferromagnetic layer, the non-magnetic layer, and the second ferromagnetic layer in order from the side closest to the wiring.

(12) In the spin element according to the above aspect, the laminated body may have a non-magnetic layer and the first ferromagnetic layer in order from the side closest to the wiring.

(13) The magnetic array according to the second aspect may include a plurality of spin elements according to the above aspect.

(14) The method for manufacturing a spin element according to the third aspect is a step of sequentially laminating a laminated film including a wiring layer and a ferromagnetic layer, and processing the wiring layer and the laminated film at the same time and extending in the first direction. , A step of forming the wiring and the laminated structure, a step of covering the side surface of the wiring and the laminated structure with an insulating layer, and a step of laminating a second wiring layer on the insulating layer and the laminated structure. The step is to simultaneously process the laminated structure and the second wiring layer to obtain read wiring extending in the second direction intersecting the laminated body and the first direction.

The spin element and the magnetic array according to the present invention have high operating efficiency. Further, the method for manufacturing a spin element according to the present invention can easily produce a spin element having excellent operating efficiency.

It is a circuit diagram of the magnetic array which concerns on 1st Embodiment. It is sectional drawing of the characteristic part of the magnetic array which concerns on 1st Embodiment. It is a top view of the characteristic part of the magnetic array which concerns on 1st Embodiment. It is sectional drawing of the magnetic resistance effect element which concerns on 1st Embodiment. It is another cross-sectional view of the magnetoresistive effect element which concerns on 1st Embodiment. It is a figure for demonstrating an example of the manufacturing method of the magnetoresistive effect element which concerns on 1st Embodiment. It is a figure for demonstrating an example of the manufacturing method of the magnetoresistive effect element which concerns on 1st Embodiment. It is a figure for demonstrating an example of the manufacturing method of the magnetoresistive effect element which concerns on 1st Embodiment. It is a figure for demonstrating an example of the manufacturing method of the magnetoresistive effect element which concerns on 1st Embodiment. It is sectional drawing of the magnetic resistance effect element which concerns on the 1st modification. It is sectional drawing of the domain wall moving element which concerns on 2nd Embodiment. It is sectional drawing of the magnetization rotating element which concerns on 3rd Embodiment.

Hereinafter, the present embodiment will be described in detail with reference to the drawings as appropriate. In the drawings used in the following description, the featured portion may be enlarged for convenience in order to make the feature easy to understand, and the dimensional ratio of each component may be different from the actual one. The materials, dimensions, and the like exemplified in the following description are examples, and the present invention is not limited thereto, and can be appropriately modified and carried out within the range in which the effects of the present invention are exhibited.

First, define the direction. One direction of one surface of the substrate Sub (see FIG. 2) described later is defined as the x direction, and the direction orthogonal to the x direction is defined as the y direction. The x direction is, for example, a direction from the first conductive layer 31 to the second conductive layer 32. The x direction is an example of the first direction. The y direction is an example of the second direction. The z direction is a direction orthogonal to the x direction and the y direction. The z direction is an example of the stacking direction. Hereinafter, the + z direction may be expressed as “up” and the −z direction may be expressed as “down”. The top and bottom do not always match the direction in which gravity is applied.

As used herein, "extending in the x direction" means that, for example, the dimension in the x direction is larger than the smallest dimension among the dimensions in the x direction, the y direction, and the z direction. The same applies when extending in other directions. Further, the term "connection" as used herein is not limited to the case of being physically connected. For example, not only when two layers are physically in contact with each other, but also when two layers are connected by sandwiching another layer between them is included in "connection". Further, when the two members are electrically connected, the case where they are connected via a switching element or the like is also included in the "connection".

"First embodiment"
FIG. 1 is a block diagram of the magnetic array 200 according to the first embodiment. The magnetic array 200 includes a plurality of magnetoresistive elements 100, a plurality of write wiring WLs, a plurality of common wiring CLs, a plurality of read wiring RLs, a plurality of first switching elements Sw1, and a plurality of second switching elements. It includes Sw2 and a plurality of third switching elements Sw3. The magnetic array 200 can be used, for example, as a magnetic memory. The magnetoresistive effect element 100 is an example of a spin element.

Each write wiring WL electrically connects a power source and one or more magnetoresistive elements 100. The common wiring CL is wiring used both when writing data and when reading data, respectively. Each of the common wiring CLs electrically connects the reference potential and one or more magnetoresistive elements 100. The reference potential is, for example, ground. The common wiring CL may be provided in each of the plurality of magnetoresistive elements 100, or may be provided across the plurality of magnetoresistive elements 100. The readout wiring RL electrically connects the power supply and one or more magnetoresistive elements 100, respectively. The power supply is connected to the magnetic array 200 during use.

Each magnetoresistive element 100 is 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 effect element 100 and the write wiring WL. The second switching element Sw2 is connected between the magnetoresistive effect element 100 and the common wiring CL. The third switching element Sw3 is connected to the read wiring RL extending over the plurality of magnetoresistive element 100.

When the first switching element Sw1 and the second switching element Sw2 are turned on, a write current flows between the write wiring WL connected to the predetermined magnetoresistive element 100 and the common wiring CL. When the second switching element Sw2 and the third switching element Sw3 are turned on, a read current flows between the common wiring CL connected to the predetermined magnetoresistive element 100 and the read wiring RL.

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, a transistor, an element utilizing a phase change of a crystal layer such as an Ovonic Threshold Switch (OTS), and a metal insulator transition. An element such as a (MIT) switch that utilizes a change in band structure, an element that utilizes a breakdown voltage such as a Zener diode and an avalanche diode, and an element whose conductivity changes as the atomic position changes.

In the magnetic array 200 shown in FIG. 1, the magnetoresistive effect element 100 connected to the same wiring shares the third switching element Sw3. The third switching element Sw3 may be provided in each magnetoresistive element 100. Further, a third switching element Sw3 may be provided in each magnetoresistive element 100, and the first switching element Sw1 or the second switching element Sw2 may be shared by the magnetoresistive element 100 connected to the same wiring.

FIG. 2 is a cross-sectional view of a characteristic portion of the magnetic array 200 according to the first embodiment. FIG. 2 is a cross section of the magnetoresistive effect element 100 cut along the xz plane passing through the center of the width in the y direction of the spin-orbit torque wiring 20 described later.

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 read wiring RL and is located, for example, in the y direction of FIG. The transistor Tr is, for example, a field effect transistor, and has a gate electrode G, a gate insulating film GI, a source S formed on the substrate Sub, and a drain D. The substrate Sub is, for example, a semiconductor substrate.

The transistor Tr and the magnetoresistive sensor 100 are electrically connected via the via wiring V, the first conductive layer 31 and the second conductive layer 32. Further, the transistor Tr and the write wiring WL or the common wiring CL are connected by a via wiring V. The via wiring V, the first conductive layer 31 and the second conductive layer 32 include a material having conductivity. The via wiring V extends in the z direction, for example.

The periphery of the magnetoresistive effect element 100 and the transistor Tr is covered with an insulating layer In. The insulating layer In is an insulating layer that insulates between the wirings of the multilayer wiring and between the elements. The insulating layer In may be, for example, silicon oxide (SiO _x ), silicon nitride (SiN _x ), silicon carbide (SiC), chromium nitride, silicon carbide (SiCN), silicon oxynitride (SiON), aluminum oxide (Al ₂ O). ₃ ), zirconium oxide (ZrO _x ), magnesium oxide (MgO), aluminum nitride (AlN) and the like.

FIG. 3 is a plan view of a characteristic portion of the magnetic array 200 according to the first embodiment. The read wiring RL extends in a second direction intersecting the first direction. The read wiring RL extends in the y direction, for example. The write wiring WL and the common wiring CL extend in the x direction, for example. The write wiring WL and the common wiring CL may extend in the y direction.

The read wiring RL has, for example, a portion that overlaps at least one of the write wiring WL and the common wiring CL when viewed from the z direction. The portion where the read wiring RL and the write wiring WL or the common wiring CL overlap when viewed from the z direction is hereinafter referred to as an intersection CP. At the intersection CP, there is an insulating layer In between the read wiring RL and the write wiring WL or the common wiring CL, and the read wiring RL and the write wiring WL or the common wiring CL are isolated from each other. On the other hand, the read wiring RL and the write wiring WL or the common wiring CL exchange heat via the insulating layer In at the intersection CP. When the magnetic array 200 has an intersection CP, the heat exhaust efficiency is improved.

Further, the read wiring RL may have a narrowed portion N when viewed from the z direction. The narrowed portion N is located at a position overlapping the laminated body 10 when viewed from the z direction. Although the details will be described later, the width of the read wiring RL in the x direction is limited at the position where it overlaps with the laminated body 10. By widening the width of the readout wiring RL at a portion other than the narrowed portion N, it is possible to prevent the retention of current and heat and improve the heat exhaust efficiency.

4 and 5 are cross-sectional views of the magnetoresistive sensor 100. FIG. 4 is a cross section of the magnetoresistive effect element 100 cut in the xz plane passing through the center of the width of the spin-orbit torque wiring 20 in the y-direction, and FIG. 5 is the center of the length of the spin-orbit torque wiring 20 in the x-direction. It is a cross section which cut the magnetoresistive effect element 100 in the yz plane passing through. In FIG. 5, the first conductive layer 31 and the second conductive layer 32 are located at positions displaced in the x direction and are shown by dotted lines.

The magnetoresistive element 100 includes, for example, a laminate 10, a spin-orbit torque wiring 20, a first conductive layer 31, and a second conductive layer 32. The spin-orbit torque wiring 20 is an example of wiring. The laminated body 10 is laminated on the spin-orbit torque wiring 20. Another layer may be provided between the laminate 10 and the spin-orbit torque wiring 20. The read wiring RL is laminated on the laminated body 10. The first conductive layer 31 and the second conductive layer 32 are connected to the spin-orbit torque wiring 20. An insulating layer may be provided between each of the first conductive layer 31 and the second conductive layer 32 and the spin-orbit torque wiring 20. The first conductive layer 31 and the second conductive layer 32 are located at positions sandwiching the laminated body 10 when viewed from the z direction.

There is an insulating layer 40 around the magnetoresistive sensor 100. The insulating layer 40 is a part of the insulating layer In. The insulating layer 40 in contact with the side wall RLs of the readout wiring RL and the side walls 10sx and 10sy of the laminated body 10 preferably has high thermal conductivity. The insulator having high thermal conductivity is, for example, MgO or AlN. When the insulating layer 40 has high thermal conductivity, the heat generated in the spin-orbit torque wiring 20 can be conducted to the readout wiring RL through the insulating layer 40, and the heat exhaust efficiency of the magnetoresistive element 100 is improved.

The resistance value of the laminated body 10 in the z direction changes as spin is injected into the laminated body 10 from the spin track torque wiring 20. The magnetoresistive effect element 100 is a magnetic element using spin orbit torque (SOT), and may be referred to as a spin orbit torque type magnetoresistive element, a spin injection type magnetoresistive element, or a spin current magnetic resistance effect element. ..

The laminate 10 is sandwiched between the spin-orbit torque wiring 20 and the read wiring RL in the z direction. The laminated body 10 is a columnar body. The plan view shape of the laminated body 10 from the z direction is, for example, a quadrangle.

The laminate 10 has, for example, a first ferromagnetic layer 1, a second ferromagnetic layer 2, a non-magnetic layer 3, and a cap layer 4 in order from the side closest to the spin-orbit torque wiring 20. The first ferromagnetic layer 1 is in contact with, for example, the spin-orbit torque wiring 20, and is laminated on the spin-orbit torque wiring 20. Spin is injected into the first ferromagnetic layer 1 from the spin-orbit torque wiring 20. The magnetization of the first ferromagnetic layer 1 receives spin-orbit torque (SOT) due to the injected spin, and the orientation direction changes. The second ferromagnetic layer 2 is in the z direction of the first ferromagnetic layer 1. The first ferromagnetic layer 1 and the second ferromagnetic layer 2 sandwich the non-magnetic layer 3 in the z direction.

The first ferromagnetic layer 1 and the second ferromagnetic layer 2 have magnetism, respectively. The magnetization of the second ferromagnetic layer 2 is less likely to change in the orientation direction than the magnetization of the first ferromagnetic layer 1 when a predetermined external force is applied. The first ferromagnetic layer 1 is sometimes referred to as a magnetization free layer, and the second ferromagnetic layer 2 is sometimes referred to as a magnetization fixed layer or a magnetization reference layer. The resistance value of the laminated body 10 changes according to the difference in the relative angles of magnetization between the first ferromagnetic layer 1 and the second ferromagnetic layer 2 sandwiching the non-magnetic layer 3.

The first ferromagnetic layer 1 and the second ferromagnetic layer 2 include a ferromagnet. 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, and at least one of these metals and B, C, and N. It is an alloy containing the element of. 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.

The first ferromagnetic layer 1 and the second ferromagnetic layer 2 may contain a Whistler alloy. Whisler alloys include intermetallic compounds with a chemical composition of XYZ or _X2YZ . X is a transition metal element or noble metal element of Group Co, Fe, Ni, or Cu on the periodic table, Y is a transition metal of Group Mn, V, Cr, or Ti, or an elemental species of X, and Z is Group III. It is a typical element of Group V. The Whisler alloy is, for example, Co ₂ FeSi, Co ₂ FeGe, Co ₂ FeGa, Co ₂ MnSi, Co ₂ Mn _1-a Fe _a Al _b Si _1-b , Co ₂ FeGe _1-c Ga _c and the like. Whisler alloys have a high spin polarizability.

The non-magnetic layer 3 contains a non-magnetic material. When the non-magnetic layer 3 is an insulator (when it is a tunnel barrier layer), for example, Al ₂ O ₃ , SiO ₂ , Mg O, Mg Al ₂ O ₄ and the like can be used as the material thereof. In addition to these, a material or the like in which a part of Al, Si, and Mg is replaced with Zn, Be, or the like can also be used. Among these, _MgO and _MgAl2O4 are materials that can realize a coherent tunnel, so that spin can be efficiently injected. When the non-magnetic layer 3 is a metal, Cu, Au, Ag or the like can be used as the material. Further, when the non-magnetic layer 3 is a semiconductor, Si, Ge, CuInSe ₂ , CuGaSe ₂ , Cu (In, Ga) Se ₂ and the like can be used as the material.

The cap layer 4 protects the second ferromagnetic layer 2. The cap layer 4 suppresses the diffusion of atoms from the second ferromagnetic layer 2. The cap layer 4 also contributes to the crystal orientation of each layer of the laminated body 10. The magnetization of the first ferromagnetic layer 1 and the second ferromagnetic layer 2 is stabilized by the presence of the cap layer 4, and the MR ratio of the laminated body 10 is improved.

The cap layer 4 may be a metal containing one or more elements selected from, for example, Ru, Ag, Al, Cu, Au, Cr, Mo, Pt, W, Ta, Pd, and Ir, or an oxide such as MgO. But it may be.

The laminate 10 may have an antiferromagnetic layer on the surface of the second ferromagnetic layer 2 opposite to the non-magnetic layer 3 via a spacer layer. The second ferromagnetic layer 2, the spacer layer, and the antiferromagnetic layer have a synthetic antiferromagnetic structure (SAF structure). The synthetic antiferromagnetic structure consists of two magnetic layers sandwiching the non-magnetic layer. The antiferromagnetic coupling between the second ferromagnetic layer 2 and the antiferromagnetic layer increases the coercive force of the second ferromagnetic layer 2 as compared with the case without the antiferromagnetic layer. The antiferromagnetic layer is, for example, IrMn, PtMn, or the like. The spacer layer contains, for example, at least one selected from the group consisting of Ru, Ir, Rh.

The laminated body 10 may have a layer other than the first ferromagnetic layer 1, the second ferromagnetic layer 2, and the non-magnetic layer 3. For example, a base layer may be provided between the spin-orbit torque wiring 20 and the laminated body 10. The base layer enhances the crystallinity of each layer constituting the laminated body 10.

The thickness H ₁₀ of the laminated body 10 is thicker than, for example, the distance L1 between the first conductive layer 31 and the laminated body 10 in the x direction. The thickness H ₁₀ of the laminated body 10 is thicker than, for example, the distance L2 between the second conductive layer 32 and the laminated body 10 in the x direction. In other words, the distance L1 and the distance L2 are shorter than, for example, the thickness H10 of the laminated body ₁₀ . The distance L1 and the distance L2 may be the same or different. When the distances L1 and L2 are short, the heat generated in the spin-orbit torque wiring 20 can be efficiently exhausted to the reading wiring RL, the first conductive layer 31 or the second conductive layer 32.

Further, the width W ₁₀ of the laminated body 10 in the x direction is, for example, wider than the distance L1. Further, the width W ₁₀ in the x direction of the laminated body is, for example, wider than the distance L2. By widening the contact area between the spin-orbit torque wiring 20 and the laminated body 10, the heat generated in the spin-orbit torque wiring 20 can be efficiently exhausted.

The side walls 10sx and 10sy of the laminated body 10 are inclined with respect to the z direction, for example. The side wall 10sx is the side wall in the x direction of the laminated body 10, and the side wall 10sy is the side wall in the y direction of the laminated body 10.

The spin-orbit torque wiring 20 is an example of wiring. For example, the spin-orbit torque wiring 20 has a length in the x direction longer than the y direction when viewed from the z direction, and extends in the x direction. The write current flows in the x direction of the spin-orbit torque wiring 20. At least a part of the spin-orbit torque wiring 20 sandwiches the first ferromagnetic layer 1 together with the non-magnetic layer 3 in the z direction.

The side walls of the spin-orbit torque wiring 20 in the x-direction and the y-direction may be inclined with respect to the z-direction. The side wall 20s in the y direction of the spin-orbit torque wiring 20 is continuous with the side wall 10sy in the y direction of the laminated body 10. The continuous side wall means that the inclination angle of the tangent plane in contact with the side wall with respect to the xy plane continuously changes or is constant.

The spin-orbit torque wiring 20 generates a spin current by the spin Hall effect when the current I flows, and injects spin into the first ferromagnetic layer 1. The spin-orbit torque wiring 20 gives, for example, a spin-orbit torque (SOT) sufficient to reverse the magnetization of the first ferromagnetic layer 1 to the magnetization of the first ferromagnetic layer 1. The spin Hall effect is a phenomenon in which a spin current is induced in a direction orthogonal to the direction in which a current flows, based on the spin-orbit interaction when a current is passed. The spin Hall effect is common to the normal Hall effect in that the moving (moving) charge (electron) can bend the moving (moving) direction. In the normal Hall effect, the direction of motion of charged particles moving in a magnetic field is bent by Lorentz force. On the other hand, in the spin Hall effect, even in the absence of a magnetic field, the direction of spin movement is bent only by the movement of electrons (only the flow of current).

For example, when a current flows through the spin-orbit torque wiring 20, the first spin oriented in one direction and the second spin oriented in the direction opposite to the first spin spin in directions orthogonal to the direction in which the current I flows. It is bent by the Hall effect. For example, the first spin oriented in the −y direction is bent in the + z direction, and the second spin oriented in the + y direction is bent in the −z direction.

In a non-magnetic material (a material that is not a ferromagnet), the number of electrons in the first spin generated by the spin Hall effect is equal to the number of electrons in the second spin. That is, the number of electrons in the first spin in the + z direction is equal to the number of electrons in the second spin in the −z direction. The first spin and the second spin flow in the direction of eliminating the uneven distribution of spins. In the movement of the first spin and the second spin in the z direction, the charge flows cancel each other out, so that the amount of current becomes zero. Spin currents without current are especially called pure spin currents.

When the electron flow of the first spin is J _↑ , the electron flow of the second spin is J _↓ , and the spin flow is J _S , it is defined as J _S = J _↑ -J _↓ . The spin current _JS occurs in the z direction. The first spin is injected into the first ferromagnetic layer 1 from the spin-orbit torque wiring 20.

The spin orbit torque wiring 20 is any one of a metal, an alloy, an intermetal compound, a metal boulder, a metal charcoal, a metal silice, and a metal phosphate having a function of generating a spin flow by the spin Hall effect when the current I flows. including.

The spin-orbit torque wiring 20 contains, for example, a non-magnetic heavy metal as a main component. Heavy metal means a metal having a specific density of yttrium (Y) or higher. The non-magnetic heavy metal is, for example, a non-magnetic metal having a d-electron or an f-electron in the outermost shell and having an atomic number of 39 or more and a large atomic number. The spin-orbit torque wiring 20 is composed of, for example, Hf, Ta, and W. Non-magnetic heavy metals have stronger spin-orbit interactions than other metals. The spin Hall effect is generated by the spin-orbit interaction, and spins are likely to be unevenly distributed in the spin-orbit torque wiring 20, and spin current _JS is likely to occur.

The spin-orbit torque wiring 20 includes, for example, at least one selected from the group consisting of Ta, W, Pt, Au, Nb, Mo, Ru, Os, Rh, Ir, Pd, and Ag. The spin-orbit torque wiring 20 is made of, for example, a simple substance metal of these elements. These elements have excellent thermal conductivity and improve the heat dissipation of the magnetoresistive sensor 100.

The spin-orbit torque wiring 20 may also contain a magnetic metal or a topological insulator. A topological insulator is a substance in which the inside of the substance is an insulator or a high resistance substance, but a metallic state in which spin polarization occurs on the surface thereof.

The read wiring RL extends in the y direction, for example. The read wiring RL has a larger heat capacity than the laminated body 10, and easily releases heat. The read wiring RL is made of a conductor. As will be described later, the read-out wiring RL also functions as a mask during manufacturing, and thus is preferably made of a hard material. The read wiring RL is, for example, Ta, W, Ru.

The width W _RLa in the x direction of the first surface RLa on the read wiring RL side of the laminated body 10 is equal to or less than the width W _10b in the x direction of the second surface 10b on the read wiring RL side of the laminate 10. In FIG. 4, an example in which the width W _RLa and the width W _10b match is shown, but the width W _RLa may be shorter than the width W _10b . When the width W _RLa is the width W _10b or less, the read wiring RL and the spin-orbit torque wiring 20 do not face each other, and it is possible to suppress an increase in capacitance between them. If the capacitance between the wires is large, a part of the pulse current leaks, making it difficult to perform high-speed operation.

The thickness H _RL of the read wiring RL is shorter than, for example, the width W _RLa of the read wiring RL in the x direction. Thickness of read wiring RL When H _RL is thick, the resistance of the read wiring RL decreases and the heat capacity increases. Further, when the laminated body 10 is processed, damage to the laminated body 10 can be suppressed.

The side wall RLs in the x direction of the read wiring RL may be inclined with respect to the z direction. The read wiring RL has a narrow width in the x direction from the first surface RLa to the second surface RLb, for example. The side wall RLs in the x direction of the read wiring RL are continuous with, for example, the side wall 10sx in the x direction of the laminated body 10.

Next, a method for manufacturing the magnetoresistive element 100 according to the present embodiment will be described with reference to FIGS. 6 to 9. 6 to 9 are views for explaining an example of a method for manufacturing the magnetoresistive sensor 100 according to the present embodiment. 6 to 9 show a plan view and a cross-sectional view at the same time, respectively.

As shown in FIG. 6, the wiring layer 80 and the laminated film 90 are sequentially formed on the first conductive layer 31, the second conductive layer 32, and the insulating layer In. The laminated film 90 is composed of, for example, a ferromagnetic layer 91, a non-magnetic layer 93, a ferromagnetic layer 92, and a cap layer 94, and is formed in this order. For laminating each layer, for example, a sputtering method, a chemical vapor deposition (CVD) method, an electron beam vapor deposition method (EB vapor deposition method), an atomic laser deposit method, or the like is used.

Next, as shown in FIG. 7, the laminated film 90 including the wiring layer 80, the ferromagnetic layer 91, the non-magnetic layer 93, the ferromagnetic layer 92, and the cap layer 94 is simultaneously processed in the x-direction and the y-direction. The processing can be performed, for example, by photolithography and etching. The wiring layer 80 becomes a spin-orbit torque wiring 20 by processing. The laminated film 90 is processed in the x direction and the y direction to become a laminated structure 90A. By processing the wiring layer 80 and the laminated film 90 at the same time, the side wall 20s in the y direction of the spin-orbit torque wiring 20 and the side wall 10sy in the y direction of the laminated body 10 are continuous. The laminated structure 90A is composed of, for example, a ferromagnetic layer 91A, a non-magnetic layer 93A, a ferromagnetic layer 92A, and a cap layer 94A. Then, the periphery of the laminated structure 90A is filled with the insulating layer 40. The upper surfaces of the insulating layer 40 and the laminated structure 90A are flattened by chemical mechanical polishing (CMP).

Next, as shown in FIG. 8, the wiring layer 95 is laminated on the insulating layer 40 and the laminated structure 90A. The wiring layer 95 extends in the xy plane.

Next, as shown in FIG. 9, the wiring layer 95 and the laminated structure 90A are simultaneously processed in the x direction to remove unnecessary portions. The wiring layer 95 becomes a read wiring RL extending in the y direction by removing unnecessary portions in the x direction. Further, the laminated structure 90A becomes the laminated body 10. By processing the wiring layer 95 and the laminated structure 90A at the same time, the side wall 10sx in the x direction of the laminated body 10 and the side wall RLs in the x direction of the read wiring RL are continuous.

The magnetoresistive sensor 100 according to the present embodiment can be manufactured by the above procedure. In the magnetoresistive effect element 100 according to the present embodiment, the laminated body 10 is processed by using the read wiring RL as a mask. As a result, the mask does not remain as a hard mask layer between the laminated body 10 and the read wiring RL. When the hard mask layer exists between the laminate 10 and the read wiring RL, the distance between the spin track torque wiring 20 and the read wiring RL is separated by the amount of the hard mask layer, and heat is generated from the spin track torque wiring 20 to the read wiring RL. Is hard to escape. On the other hand, when the read wiring RL also serves as a mask, the distance between the spin-orbit torque wiring 20 and the read wiring RL becomes short, and the heat generated in the spin-orbit torque wiring 20 can be efficiently dissipated.

Further, when the read wiring RL becomes a mask, the width W _RLa in the x direction of the first surface RLa on the read wiring RL side of the laminate 10 is inevitably x of the second surface 10b on the read wiring RL side of the laminate 10. The width in the direction W is _10b or less. Therefore, the read wiring RL and the spin-orbit torque wiring 20 do not face each other, and it is possible to suppress an increase in capacitance between them.

Although an example of the magnetoresistive sensor 100 according to the first embodiment has been shown above, it is possible to add, omit, replace, and make other changes to the configuration within a range that does not deviate from the gist of the present invention.

FIG. 10 is a cross-sectional view of the magnetoresistive effect element 101 according to the first modification. FIG. 10 is an xz cross section passing through the center of the spin-orbit torque wiring 20 in the y direction. In FIG. 10, the same components as those in FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted.

The read wiring RL1 shown in FIG. 10 has an xz cross-sectional shape different from that of the read wiring RL shown in FIG. The read wiring RL1 is constricted in the x direction. The read wiring RL1 has a portion whose width in the x direction is narrower than that of the first surface RL1a and the second surface RL1b. When the read wiring RL1 has a constriction in the x direction, it is possible to suppress an increase in the capacitance between the read wiring RL1 and the spin-orbit torque wiring 20.

"Second embodiment"
FIG. 11 is a cross-sectional view of the domain wall moving element 110 according to the second embodiment. The domain wall moving element 110 is an example of a spin element. The domain wall moving element 110 replaces the magnetoresistive effect element 100 according to the first embodiment.

The domain wall moving element 110 is an element whose resistance value changes due to the movement of the domain wall DW. The domain wall moving element 110 has a domain wall moving layer 50, a laminate 11, a first conductive layer 31, and a second conductive layer 32. The domain wall moving layer 50 is an example of wiring. The laminated body 11 has a non-magnetic layer 3, a first ferromagnetic layer 1, and a cap layer 4 from the side closer to the domain wall moving layer 50. In this case, the first ferromagnetic layer 1 is a magnetization fixed layer.

The domain wall moving layer 50 is a magnetic layer. The domain wall moving layer 50 contains a ferromagnet. The magnetic material constituting the magnetic wall moving layer 50 is a metal selected from the group consisting of Cr, Mn, Co, Fe and Ni, an alloy containing one or more of these metals, and these metals and B, C and N. An alloy or the like containing at least one kind of element can be used. Specific examples thereof include Co—Fe, Co—Fe—B, and Ni—Fe.

The domain wall moving layer 50 is a layer capable of magnetically recording information by changing the internal magnetic state. The domain wall moving layer 50 has two magnetic domains inside, and the boundary between these magnetic domains is the domain wall DW.

The domain wall moving layer 50 corresponds to the spin-orbit torque wiring 20 in the first embodiment, and the laminated body 11 corresponds to the laminated body 10 in the first embodiment. The relationship between the domain wall moving layer 50 and the laminated body 11 and the other structures is the same as in the first embodiment.

For example, the width W _RLa in the x direction of the first surface RLa on the read wiring RL side of the laminate 11 is equal to or less than the width W _11b in the x direction of the second surface 11b on the read wiring RL side of the laminate 11.

The thickness H ₁₁ of the laminated body 11 is thicker than, for example, the distance L1 between the first conductive layer 31 and the laminated body 11 in the x direction. The thickness H ₁₁ of the laminated body 10 is thicker than, for example, the distance L2 between the second conductive layer 32 and the laminated body 11 in the x direction.

Further, the width W ₁₁ of the laminated body 11 in the x direction is, for example, wider than the distance L1. Further, the width W ₁₁ in the x direction of the laminated body is, for example, wider than the distance L2. The side wall 11sx in the x direction of the laminated body 11 is continuous with the side wall RLs in the x direction of the read wiring RL, and the side wall in the y direction of the laminated body 11 is continuous with the side wall in the y direction of the domain wall moving layer 50.

The domain wall moving element 110 according to the second embodiment can efficiently exhaust heat generated in the domain wall moving layer 50, and can suppress an increase in capacitance between the read wiring RL1 and the domain wall moving layer 50. ..

"Third embodiment"
FIG. 12 is a cross-sectional view of the magnetization rotating element 120 according to the third embodiment. The magnetizing rotation element 120 is an example of a spin element. The magnetization rotating element 120 replaces the magnetoresistive effect element 100 according to the first embodiment.

The magnetizing rotating element 120, for example, incidents light on 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 magneto-optic Kerr effect, the deflection state of the reflected light changes. The magnetization rotating element 120 can be used, for example, as an optical element such as an image display device that utilizes the difference in the deflection state of light.

In addition, the magnetization rotating element 120 can be used alone as an anisotropic magnetic sensor, an optical element utilizing the magnetic Faraday effect, and the like.

The magnetization rotating element 120 has a spin-orbit torque wiring 20, a laminate 12, a first conductive layer 31, and a second conductive layer 32. The laminated body 12 has a first ferromagnetic layer 1 and a cap layer 4 from the side closer to the spin-orbit torque wiring 20.

The laminated body 12 corresponds to the laminated body 10 in the first embodiment. The relationship between the laminated body 12 and the other structures is the same as in the first embodiment.

In this case, the read wiring RL is made of, for example, a transparent electrode material. The transparent electrode material is, for example, indium zinc oxide (IZO), indium-tin oxide (ITO), tin oxide (SnO ₂ ), antimony oxide-tin oxide system (ATO), zinc oxide (ZnO), fluorine-doped oxidation. Zinc (FTO), indium oxide (In ₂ O ₃ ) and the like.

For example, the width W _RLa in the x direction of the first surface RLa on the read wiring RL side of the laminate 12 is equal to or less than the width W _12b in the x direction of the second surface 12b on the read wiring RL side of the laminate 12.

The thickness H ₁₂ of the laminated body 12 is thicker than, for example, the distance L1 between the first conductive layer 31 and the laminated body 12 in the x direction. The thickness H ₁₂ of the laminated body 12 is thicker than, for example, the distance L2 between the second conductive layer 32 and the laminated body 12 in the x direction.

Further, the width W ₁₂ in the x direction of the laminated body 12 is, for example, wider than the distance L1. Further, the width W ₁₂ in the x direction of the laminated body is, for example, wider than the distance L2. The x-direction side wall 12sx of the laminated body 12 is continuous with the x-direction side wall RLs of the read wiring RL, and the y-direction side wall of the laminated body 12 is continuous with the y-direction side wall of the spin-orbit torque wiring 20.

The magnetized rotating element 120 according to the third embodiment can efficiently exhaust the heat generated in the spin-orbit torque wiring 20, and the capacitance between the read wiring RL1 and the spin-orbit torque wiring 20 becomes large. It can be suppressed.

Up to this point, preferred embodiments of the present invention have been exemplified based on the first to third embodiments, but the present invention is not limited to these embodiments. For example, the characteristic configuration in each embodiment may be applied to other embodiments.

1 ... 1st ferromagnetic layer, 2 ... 2nd ferromagnetic layer, 3 ... non-magnetic layer, 4 ... cap layer, 10, 11, 12 ... laminated body, 10b, 11b, 12b ... second surface, 10sx, 10sy, 11sx, 12sx, 20s, RLs ... Side wall, 20 ... Spin track torque wiring, 31 ... First conductive layer, 32 ... Second conductive layer, 40 ... Insulation layer, 50 ... Domain wall moving layer, 80, 95 ... Wiring layer, 90 ... Laminated film, 90A ... Laminated structure, 91,91A, 92,92A ... ferromagnetic layer, 93,93A ... non-magnetic layer, 94,94A ... cap layer, 100,101 ... magnetic resistance effect element, 110 ... domain wall movement Element, 120 ... Magnetized rotating element, 200 ... Magnetic array, CL ... Common wiring, CP ... Crossing, DW ... Domain wall, In ... Insulation layer, N ... Narrowed part, RL, RL1 ... Read wiring, RLa, RL1a ... First surface , RLb, RL1b ... Second surface, WL ... Write wiring

Claims (14)

Wiring extending in the first direction and
A laminate that is laminated on the wiring and includes a first ferromagnetic layer,
A readout wiring that is laminated on the laminate and extends in a second direction that intersects the first direction.
A spin element whose width in the first direction of the first surface of the read wiring on the side of the laminate is equal to or less than the width of the second surface of the layer on the side of the read wiring in the first direction. The spin element according to claim 1, wherein the side wall of the laminated body and the side wall of the read wiring are continuous. Further, a first conductive layer and a second conductive layer connected to the wiring are provided.
The first conductive layer and the second conductive layer sandwich the laminated body when viewed from the stacking direction.
The spin element according to claim 1 or 2, wherein the distance between the first conductive layer and the laminated body in the first direction is shorter than the thickness of the laminated body in the laminated body. The spin element according to any one of claims 1 to 3, wherein the read wiring is narrowed at a position overlapping the laminated body when viewed from the stacking direction. Further, a first conductive layer and a second conductive layer connected to the wiring are provided.
The first conductive layer and the second conductive layer sandwich the laminated body when viewed from the stacking direction.
The spin element according to any one of claims 1 to 4, wherein the width of the laminated body in the first direction is wider than the distance between the first conductive layer and the laminated body in the first direction. Further provided with an insulating layer in contact with the side wall of the laminate and the side wall of the readout wiring.
The spin element according to any one of claims 1 to 5, wherein the insulating layer is AlN or MgO. Further provided with write wiring and common wiring connected to the wiring,
The spin element according to any one of claims 1 to 6, wherein at least one of the write wiring and the common wiring has a portion that overlaps with the read wiring when viewed from the stacking direction. The spin element according to any one of claims 1 to 7, wherein the read wiring has a portion whose width in the first direction is narrower than that of the first surface and the second surface facing the first surface. The spin element according to any one of claims 1 to 8, wherein the thickness of the read wiring in the stacking direction is narrower than the width of the read wiring in the first direction. The spin element according to any one of claims 1 to 9, wherein the side wall of the laminated body and the side wall of the read wiring are inclined with respect to the stacking direction. The spin element according to any one of claims 1 to 10, wherein the laminated body has the first ferromagnetic layer, the non-magnetic layer, and the second ferromagnetic layer in order from the side closest to the wiring. The spin element according to any one of claims 1 to 10, wherein the laminated body has a non-magnetic layer and the first ferromagnetic layer in this order from the side closest to the wiring. A magnetic array comprising a plurality of spin elements according to any one of claims 1 to 12. The process of laminating a laminated film including a wiring layer and a ferromagnetic layer in order,
A step of simultaneously processing the wiring layer and the laminated film to form a wiring and a laminated structure extending in the first direction.
The step of covering the side surface of the wiring and the laminated structure with an insulating layer,
A step of laminating a second wiring layer on the insulating layer and the laminated structure,
A method for manufacturing a spin element, comprising a step of simultaneously processing the laminated structure and the second wiring layer to form a read-out wiring extending in a second direction intersecting the laminated body and the first direction.

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