Magnetic device

Abstract

A magnetic device includes a laminate including a first ferromagnetic layer, a second ferromagnetic layer, and a non-magnetic layer interposed between the first ferromagnetic layer and the second ferromagnetic layer, a first insulating layer covering a side surface of the laminate, and a heat sink located outside the first insulating layer with the laminate as a reference, the distance between the side surface of the laminate and the heat sink varying depending on the position of the laminate in the stacking direction.

Description

TECHNICAL FIELD

[0001] The present application relates to a magnetic device. BACKGROUND

[0002] A giant magnetoresistance (GMR) element composed of a multilayer film of a ferromagnetic layer and a nonmagnetic layer, and a tunnel magnetoresistance (TMR) element using an insulating layer (tunnel barrier layer, barrier layer) in the nonmagnetic layer as a magnetoresistance effect element are well known. The magnetoresistance effect element can be applied to a magnetic sensor, a high-frequency component, a magnetic head, and a nonvolatile random access memory (MRAM).

[0003] The MRAM is a storage element integrated with the magnetoresistance effect element. The MRAM uses a characteristic that the resistance of the magnetoresistance effect element changes when the direction of mutual magnetization of two ferromagnetic layers sandwiching a nonmagnetic layer in the magnetoresistance effect element changes to read and write data.

[0004] For example, Japanese Patent Application Publication No. 2017-216286 describes a magnetoresistance effect element that performs writing using spin-orbit torque (SOT). SUMMARY

[0005] The magnetoresistance effect element sometimes generates heat at the time of data writing. The heat generated by the magnetoresistance effect element can become a cause of adverse effects on a control element, another magnetoresistance effect element, or the like.

[0006] The present application was achieved in view of the above-described circumstances, and an object thereof is to provide a magnetic device capable of efficiently dissipating heat generated by a magnetoresistance effect element.

[0007] The present application provides the following means in order to solve the above-described problems.

[0008] (1) The magnetic device of the first embodiment includes: a laminate including a first ferromagnetic layer, a second ferromagnetic layer, and a nonmagnetic layer sandwiched by the first ferromagnetic layer and the second ferromagnetic layer; a first insulating layer covering a side surface of the laminate; and a heat sink located outside the first insulating layer with the laminate as a reference, the distance of the side surface of the laminate from the heat sink being different depending on the position in the stacking direction of the laminate.

[0009] (2) In the magnetic device of the above-described embodiment, the heat sink can also be inclined with respect to the stacking direction.

[0010] (3) In the magnetic device of the above-described embodiment, the side surface of the laminate can also be inclined with respect to the stacking direction, and the inclination direction of the side surface of the laminate with respect to the stacking direction can be the same as the inclination direction of the heat sink with respect to the stacking direction.

[0011] (4) In the magnetic device of the above embodiment, the magnetic device can further include a wiring connected to the layered body and extending in the first direction, and the heat sink can include a plurality of heat sinks each extending in the first direction, and the layered body can be sandwiched by the two heat sinks.

[0012] (5) In the magnetic device of the above embodiment, the heat sink can surround a side surface of the layered body.

[0013] (6) In the magnetic device of the above embodiment, the heat sink can include microparticles having an average particle diameter of 10 nm or less.

[0014] (7) In the magnetic device of the above embodiment, the heat sink can include a metal.

[0015] (8) In the magnetic device of the above embodiment, the metal can be any one of copper, cobalt, tungsten, tantalum, ruthenium, and aluminum.

[0016] (9) In the magnetic device of the above embodiment, the heat sink can be a non-magnetic body.

[0017] (10) In the magnetic device of the above embodiment, the heat sink can be in contact with a portion of the layered body.

[0018] (11) The magnetic device of the above embodiment can further include a wiring connected to the layered body and extending in the first direction, and the heat sink can be in contact with the wiring.

[0019] (12) In the magnetic device of the above embodiment, the height of the layered body in the layered direction can be higher than the height of the layered body.

[0020] (13) In the magnetic device of the above embodiment, the heat sink can have a plurality of heat sinks outward of the layered body.

[0021] (14) In the magnetic device of the above embodiment, a space can be provided outward of the heat sink with respect to the layered body. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a schematic view of a magnetic device of a first embodiment.

[0023] Figure 2 is a cross-sectional view of the magnetic device of the first embodiment.

[0024] Figure 3 is a cross-sectional view of a vicinity of a magnetic resistance effect element of the magnetic device of the first embodiment.

[0025] Figure 4is another cross-sectional view obtained by enlarging the vicinity of the magnetoresistive effect element of the magnetic device of the first embodiment.

[0026] Figure 5 is a plan view obtained by enlarging the vicinity of the magnetoresistive effect element of the magnetic device of the first embodiment.

[0027] Figure 6 is a cross-sectional view obtained by enlarging the vicinity of the magnetoresistive effect element of the magnetic device of the first modification.

[0028] Figure 7 is a cross-sectional view obtained by enlarging the vicinity of the magnetoresistive effect element of the magnetic device of the second modification.

[0029] Figure 8 is a cross-sectional view obtained by enlarging the vicinity of the magnetoresistive effect element of the magnetic device of the third modification.

[0030] Figure 9 is a cross-sectional view obtained by enlarging the vicinity of the magnetoresistive effect element of the magnetic device of the fourth modification.

[0031] Figure 10 is a cross-sectional view obtained by enlarging the vicinity of the magnetoresistive effect element of the magnetic device of the fifth modification.

[0032] Figure 11 is a cross-sectional view obtained by enlarging the vicinity of the magnetoresistive effect element of the magnetic device of the sixth modification.

[0033] Figure 12 is a cross-sectional view obtained by enlarging the vicinity of the magnetoresistive effect element of the magnetic device of the seventh modification.

[0034] Figure 13 is a plan view obtained by enlarging the vicinity of the magnetoresistive effect element of the magnetic device of the second embodiment.

[0035] Figure 14 is a schematic view of the magnetic device of the third embodiment.

[0036] Figure 15 is a cross-sectional view of the magnetic device of the third embodiment.

[0037] Figure 16 is a cross-sectional view obtained by enlarging the vicinity of the magnetoresistive effect element of the magnetic device of the third embodiment.

[0038] Explanation of symbols:

[0039] 1, 4… First ferromagnetic layer, 2, 5… Second ferromagnetic layer, 3, 6… Non-magnetic layer, 10, 11, 12… Stacked structure, 20, 21… Spin-orbit torque wiring, 31, 32, 33… Electrode, 40, 41, 42, 43, 44, 45, 46, 47… Heat sink, 50, 51… Space, 90… First insulating layer, 100, 101, 102, 103, 104, 105, 106, 107, 110, 120… Magnetoresistive element, 200, 220… Magnetic device, BL… Bit line, CL… Common line, In… Insulator, RL… Readout line, SL… Source line, Sub… Substrate, WL… Write line. Detailed Implementation

[0040] The following is a brief reference to the appendix. Figure 1 The following description will provide a detailed account of this embodiment. In the accompanying drawings used in the following description, features are sometimes shown as enlarged portions for ease of understanding, and the dimensions and ratios of the constituent elements may differ from the actual dimensions. The materials, dimensions, etc., illustrated in the following description are examples, and the present invention is not limited thereto; appropriate modifications and implementations can be made within the scope of achieving the effects of the present invention.

[0041] First, the orientation is defined. The substrate Sub (refer to...) will be described later. Figure 2 One direction of one face of the magnetoresistive element is defined as the x-direction, and the direction orthogonal to the x-direction is defined as the y-direction. The x-direction, for example, is the direction from electrode 31 towards electrode 32. The z-direction is the direction orthogonal to both the x- and y-directions. The z-direction is an example of a stacking direction. The direction from the substrate Sub towards the magnetoresistive element 100 is defined as the +z-direction. Hereinafter, the +z-direction is sometimes referred to as "up" and the -z-direction as "down". Up and down are not necessarily consistent with the direction in which gravity is applied.

[0042] In this specification, "extending in the x-direction" means, for example, that the dimension in the x-direction is greater than the smallest dimension among the dimensions in the x, y, and z directions. The same applies when extending in other directions.

[0043] (First Embodiment)

[0044] Figure 1 This is a structural diagram of the magnetic device 200 according to the first embodiment. The magnetic device 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. The magnetic device 200 can be used in spin memristors, magnetic memories, IoT devices, neuromorphic devices, etc.

[0045] The magnetoresistive effect elements 100 are arranged, for example, in a matrix. Each of the magnetoresistive effect elements 100 is connected to a write line WL, a read line RL, and a common line CL.

[0046] The write line WL electrically connects a power source to one or more of the magnetoresistive effect elements 100. The common line CL is a wiring used at both the time of writing data and the time of reading out data. The common line CL electrically connects a reference potential to one or more of the magnetoresistive effect elements 100. The reference potential is, for example, ground. The common line CL can be provided for each of a plurality of the magnetoresistive effect elements 100, or can be provided so as to extend over the plurality of the magnetoresistive effect elements 100. The read line RL electrically connects a power source to one or more of the magnetoresistive effect elements 100. The power source is connected to the magnetic device 200 at the time of use.

[0047] Each of the magnetoresistive effect elements 100 is connected to a first switch element Swl, a second switch element Sw2, and a third switch element Sw3. The first switch element Swl is connected between the magnetoresistive effect element 100 and the write line WL. The second switch element Sw2 is connected between the magnetoresistive effect element 100 and the common line CL. The third switch element Sw3 is connected to the read line RL extending over a plurality of the magnetoresistive effect elements 100.

[0048] When the first switch element Swl and the second switch element Sw2 are made ON, a write current flows between the write line WL and the common line CL connected to a prescribed magnetoresistive effect element 100. If the write current flows in the magnetoresistive effect element 100, data is recorded in the magnetoresistive effect element 100. When the second switch element Sw2 and the third switch element Sw3 are made ON, a read current flows between the common line CL and the read line RL connected to a prescribed magnetoresistive effect element 100. If the read current flows in the magnetoresistive effect element 100, data is read from the magnetoresistive effect element 100.

[0049] The first switch element Swl, the second switch element Sw2, and the third switch element Sw3 are elements that control the flow of current. The first switch element Swl, the second switch element Sw2, and the third switch element Sw3 are, for example, elements that utilize the phase change of a crystalline layer like a transistor, a bidirectional threshold switch (OTS: Ovonic Threshold Switch), elements that utilize the change of the energy band structure like a metal insulator transition (MIT) switch, elements that utilize the breakdown voltage like a Zener diode and an avalanche diode, elements in which the conductivity changes with the change of the atomic position.

[0050] In Figure 2The magnetoresistive effect elements 100 connected to the same wiring share the third switch element Sw3 in the illustrated magnetic device 200. The third switch element Sw3 can also be provided for each magnetoresistive effect element 100. Alternatively, the third switch element Sw3 can be provided for each magnetoresistive effect element 100, and the first switch element Swl or the second switch element Sw2 can be shared among the magnetoresistive effect elements 100 connected to the same wiring.

[0051] Figure 2 is a cross-sectional view of the magnetic device 200 of the first embodiment. Figure 2 is a cross-section of the magnetic device 200 taken with an xz plane passing through the center of the width in the y direction of the spin-orbit torque wiring 20.

[0052] Figure 2 The first switch element Swl and the second switch element Sw2 illustrated are transistors Tr. The third switch element Sw3 is connected to the read line RL, for example, at a position different from that of the Figure 3 x direction. The transistor Tr is, for example, a field-effect type 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 positional relationship between the source S and the drain D is one example, and can be reversed. The substrate Sub is, for example, a semiconductor substrate.

[0053] The transistor Tr is electrically connected to the magnetoresistive effect element 100 via a via wiring V and electrodes 31, 32. In addition, the transistor Tr is connected to the write line WL or the common line CL through the via wiring V. In addition, the read line RL is electrically connected to the magnetoresistive effect element 100 via an electrode 33. The via wiring V and the electrodes 31, 32, 33 contain a material having electrical conductivity.

[0054] The periphery of the magnetoresistive effect element 100 and the transistor Tr is covered with an insulator In. The insulator In is an insulating layer that insulates between wirings of the multilayer wiring or between elements. The insulator In is, for example, silicon oxide (SiO x ), silicon nitride (SiN x ), silicon carbide (SiC), chromium nitride, silicon carbonitride (SiCN), silicon oxynitride (SiON), aluminum oxide (Al203), zirconium oxide (ZrO x ), or the like.

[0055] Figure 4 and Figure 3 is a cross-sectional view of the magnetic device 200 of the first embodiment. Figure 4 is a cross-section of the magnetoresistive effect element 100 taken with an xz plane passing through the center of the width in the y direction of the spin-orbit torque wiring 20. Figure 5 is a cross-section of the magnetoresistive effect element 100 taken with a yz plane passing through the center of the width in the x direction of the laminated body 10. Figure 4is a plan view of the magnetoresistive effect element 100 viewed from the z direction.

[0056] The magnetoresistive effect element 100 has, for example, a laminate 10 and a spin-orbit torque wiring 20. A resistance value in the z direction of the laminate 10 is changed by injecting a spin from the spin-orbit torque wiring 20 to the laminate 10. The magnetoresistive effect element 100 is a magnetoresistive effect element using a spin-orbit torque (SOT), and is sometimes referred to as a spin-orbit torque type magnetoresistive effect element, a spin injection type magnetoresistive effect element, or a spin current magnetoresistive effect element.

[0057] The magnetoresistive effect element 100 is a three-terminal type element connected with three electrodes 31, 32, and 33. The electrodes 31, 32, and 33 are composed of a material having conductivity. The electrodes 31, 32, and 33 contain, for example, any one selected from Al, Cu, Ta, Ti, Zr, NiCr, and nitride (for example, TiN, TaN, SiN). The electrode 33 can also function as a hard mask used in the manufacturing process of the magnetoresistive effect element 100. The electrode 33 can also be composed of a transparent electrode material, for example.

[0058] The electrode 31 and the electrode 32 are connected with the spin-orbit torque wiring 20 at a position sandwiching the laminate 10 in the x direction when viewed from the z direction. The electrode 33 is connected with the laminate 10. The laminate 10 is connected with a read line RL via the electrode 33. The read line RL extends in the x direction.

[0059] A heat sink 40 is provided in the vicinity of the magnetoresistive effect element 100. The heat sink 40 is located outside a first insulating layer 90 covering the side surface of the laminate 10 with the laminate 10 as a reference. The first insulating layer 90 is a part of the insulator In and is located between the laminate 10 and the heat sink 40.

[0060] The heat sink 40 is, for example, a layer extending in the x direction. Figures 3-5 The heat sink 40 is provided in the vicinity of the laminate 10, and the two heat sinks 40 sandwich the laminate 10 in the y direction.

[0061] The heat sink 40 is located in the vicinity of the side surface of the laminate 10, and the shortest distance between the laminate 10 and the heat sink 40 in the x direction varies depending on the position in the z direction. The distance between the laminate 10 and the heat sink 40 in the x direction varies depending on the position in the z direction, and thus it is possible to prevent the side surface of the laminate 10 from being in surface contact with the heat sink 40 and to prevent short circuit of the laminate 10.

[0062] The heat sink 40 is inclined with respect to the z direction. The heat sink 40 is inclined toward the laminate 10, and the upper end is closer to the laminate 10 than the lower end, for example. The inclination direction of the heat sink 40 with respect to the z direction is the same as the inclination direction of the side surface of the laminate 10 with respect to the z direction, for example.

[0063] The thickness of the heat sink 40 is narrower than the width of the laminate 10. The thickness of the heat sink 40 is an average value of the thickness of the heat sink 40 in a direction orthogonal to a tangent plane of the heat sink 40, and the average value is an average value of the thickness of five points different in the z direction. The width of the laminate 10 is, for example, the width of the laminate 10 in the x direction or the y direction, and can also be a diameter.

[0064] If the thickness of the heat sink 40 is thin, the proportion of the heat sink 40 with respect to the whole becomes small, and the integration of the magnetic device 200 as a whole is improved. The thickness of the heat sink 40 is, for example, thicker at the lower end than at the upper end. If the film thickness of the heat sink 40 of a portion close to the spin-orbit torque wiring 20 that easily generates heat at the time of writing is thick, heat can be effectively released.

[0065] The height of the heat sink 40 in the z direction is, for example, higher than that of the laminate 10. If the height of the heat sink 40 is higher than that of the laminate 10, heat can be effectively released from any position in the z direction of the laminate 10.

[0066] The heat sink 40 has a higher thermal conductivity than the first insulating layer 90. The heat sink 40 contains, for example, a metal. The heat sink 40 contains, for example, any one of copper, cobalt, tungsten, tantalum, ruthenium, and aluminum. The heat sink 40 is, for example, a non-magnetic body. If the heat sink 40 is a non-magnetic body, it is possible to prevent the application of a leakage magnetic field from the heat sink 40 to the laminate 10.

[0067] The heat sink 40 preferably contains, for example, microparticles having an average particle diameter of 10 nm or less, and preferably contains microparticles having a particle diameter of 5 nm or less. A contact resistance is generated at the contact interface of different microparticles. The heat sink 40 has a high resistance while ensuring thermal conductivity by containing microparticles. If the resistance of the heat sink 40 is high, it is possible to suppress the occurrence of short-circuiting via the heat sink 40.

[0068] The heat sink 40 is, for example, in contact with the spin-orbit torque wiring 20. The spin-orbit torque wiring 20 is a portion through which a writing current flows, and easily generates heat. By releasing heat from the spin-orbit torque wiring 20 via the heat sink 40, it is possible to suppress short-circuiting and the like of the spin-orbit torque wiring 20. In addition, by the presence of the heat sink 40 in the vicinity of the first ferromagnetic layer 1 in which magnetization is reversed, it is possible to suppress a decrease in the magnetization stability of the first ferromagnetic layer 1.

[0069] The laminate 10 is sandwiched by the spin-orbit torque wiring 20 and the electrode 33 in the z direction. The laminate 10 is a columnar body. The laminate 10 has, for example, a circular shape, an elliptical shape, or a quadrangular shape in a plan view observed in the z direction. The side surface of the laminate 10 is, for example, inclined with respect to the z direction.

[0070] The laminate 10, for example, has a first ferromagnetic layer 1, a second ferromagnetic layer 2, and a nonmagnetic layer 3. The first ferromagnetic layer 1, for example, is in contact with and stacked on a 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 is affected by the injected spin and undergoes a spin-orbit torque (SOT), resulting in a change in orientation. The first ferromagnetic layer 1 and the second ferromagnetic layer 2 are sandwiched between the nonmagnetic layer 3 in the z-direction.

[0071] The first ferromagnetic layer 1 and the second ferromagnetic layer 2 are each magnetized. The orientation of the magnetization of the second ferromagnetic layer 2 is less likely to change compared to the magnetization of the first ferromagnetic layer 1 when a specified external force is applied. Sometimes the first ferromagnetic layer 1 is referred to as the magnetization-free layer, and the second ferromagnetic layer 2 as the magnetization-fixed layer or magnetization-reference layer. The resistance value of the laminate 10 varies depending on the relative angle of magnetization between the first ferromagnetic layer 1 and the second ferromagnetic layer 2 that hold the non-magnetic layer 3.

[0072] The first ferromagnetic layer 1 and the second ferromagnetic layer 2 contain ferromagnetic materials. Ferromagnetic materials may be, for example, metals selected from Cr, Mn, Co, Fe, and Ni; alloys containing one or more of these metals; or alloys containing these metals and at least one of the elements selected from B, C, and N. Examples of ferromagnetic materials include Co-Fe, Co-Fe-B, Ni-Fe, Co-Ho alloys, Sm-Fe alloys, Fe-Pt alloys, Co-Pt alloys, and CoCrPt alloys.

[0073] The first ferromagnetic layer 1 and the second ferromagnetic layer 2 may also contain Hassler alloys. Hassler alloys contain intermetallic compounds with a chemical composition of XYZ or X2YZ. X is a transition metal or noble metal element from the Co, Fe, Ni, or Cu group on the periodic table; Y is a transition metal from the Mn, V, Cr, or Ti group or an element of X; and Z is a typical element from Groups III to V. Examples of Hassler alloys include Co2FeSi, Co2FeGe, Co2FeGa, Co2MnSi, and Co2Mn. 1-a Fe a Al b Si 1-b Co2FeGe 1- c Ga c Etc. Hassler alloys exhibit high spin polarization.

[0074] The non-magnetic layer 3 includes a non-magnetic substance. In a case where the non-magnetic layer 3 is an insulator (in a case where it is a tunnel barrier layer), as a material thereof, for example, Al2O3, SiO2, MgO, MgAl2O4, or the like can be used. In addition, besides these, a material in which a part of Al, Si, Mg is substituted with Zn, Be, or the like, or the like can be used. Among them, MgO, MgAl2O4 are materials that can achieve coherent tunneling, so spin can be injected efficiently. In a case where the non-magnetic layer 3 is a metal, as a material thereof, Cu, Au, Ag, or the like can be used. Further, in a case where the non-magnetic layer 3 is a semiconductor, as a material thereof, Si, Ge, CuInSe2, CuGaSe2, Cu(In,Ga)Se2, or the like can be used.

[0075] The laminated body 10 can also 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 can be provided between the spin-orbit torque wiring 20 and the first ferromagnetic layer 1. The base layer improves the crystallinity of each layer constituting the laminated body 10. In addition, for example, a capping layer can be provided on the uppermost surface of the laminated body 10.

[0076] In addition, the laminated body 10 can also provide a ferromagnetic layer on the side of the second ferromagnetic layer 2 opposite to the non-magnetic layer 3 with a spacer layer interposed therebetween. The second ferromagnetic layer 2, the spacer layer, and the ferromagnetic layer become a synthetic antiferromagnetic structure (SAF structure). The synthetic antiferromagnetic structure is composed of two magnetic layers sandwiching a non-magnetic layer. By the antiferromagnetic coupling between the second ferromagnetic layer 2 and the ferromagnetic layer, the coercivity of the second ferromagnetic layer 2 becomes larger than in a case where the ferromagnetic layer is not provided. The ferromagnetic layer is, for example, IrMn, PtMn, or the like. The spacer layer includes, for example, at least one selected from Ru, Ir, Rh.

[0077] The spin-orbit torque wiring 20 extends, for example, in the x direction. A write current flows along the spin-orbit torque wiring 20. At least a part of the spin-orbit torque wiring 20 sandwiches the first ferromagnetic layer 1 in the z direction together with the non-magnetic layer 3.

[0078] The spin orbit torque wiring 20 generates a spin current by the spin Hall effect when a current I flows, and injects a spin into the first ferromagnetic layer 1. The spin orbit torque wiring 20, for example, imparts a spin orbit torque (SOT) to the magnetization of the first ferromagnetic layer 1 that can only invert 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 flow direction of a current based on spin orbit interaction in the case where a current flows. The spin Hall effect is the same as the usual Hall effect in that the moving (moving) direction of the charge (electron) is bent. The usual Hall effect is that the moving direction of a charged particle moving in a magnetic field is bent by the Lorentz force. In contrast, the spin Hall effect bends the moving direction of the spin only by the movement of the electron (only the flow of the current) even in the absence of a magnetic field.

[0079] For example, when a current flows in the spin orbit torque wiring 20, a first spin oriented in one direction and a second spin oriented in the opposite direction of the first spin are bent in a direction orthogonal to the flow direction of the current by the spin Hall effect, respectively. For example, a first spin oriented in the -y direction is bent toward the +z direction, and a second spin oriented in the +y direction is bent toward the -z direction.

[0080] The number of electrons of the first spin and the number of electrons of the second spin of the non-magnetic body (a material other than a ferromagnetic body) generated by the spin Hall effect are equal. That is, the number of electrons of the first spin toward the +z direction is equal to the number of electrons of the second spin toward the -z direction. The first spin and the second spin flow in a direction that cancels the inhomogeneity of the spin. In the movement of the first spin and the second spin in the z direction, the flow of the charge cancels each other, so the amount of current is zero. The spin current not accompanied by the current is particularly referred to as a pure spin current.

[0081] If the flow of the electrons of the first spin is represented as J ↑ , the flow of the electrons of the second spin is represented as J ↓ , and the spin current is represented as J S , then J S = J ↑ - J ↓ is defined. The spin current J S is generated in the z direction. The first spin is injected from the spin orbit torque wiring 20 to the first ferromagnetic layer 1.

[0082] The spin orbit torque wiring 20 contains any one of a metal, an alloy, an intermetallic compound, a metal boride, a metal carbide, a metal silicide, a metal phosphide having a function of generating a spin current by the spin Hall effect when a current I flows.

[0083] The spin-orbit torque wiring 20 contains, for example, a non-magnetic heavy metal as a main component. The heavy metal refers to a metal having a specific gravity of or more than yttrium (Y). The non-magnetic heavy metal is, for example, a non-magnetic metal having an atomic number of or more than 39, which has a d electron or an f electron in the outermost shell. The spin-orbit torque wiring 20 is composed of, for example, Hf, Ta, and W. The non-magnetic heavy metal generates a stronger spin-orbit interaction than other metals. The spin Hall effect is generated by the spin-orbit interaction, and spins easily become non-uniform in the spin-orbit torque wiring 20, and a spin current J is easily generated S .

[0084] The spin-orbit torque wiring 20 can contain a magnetic metal in addition to this. The magnetic metal is a ferromagnetic metal or an antiferromagnetic metal. A trace amount of the magnetic metal contained in the non-magnetic body becomes a scattering factor of the spin. The trace amount refers to, for example, 3% or less of the total molar ratio of the elements constituting the spin-orbit torque wiring 20. When the spin is scattered by the magnetic metal, the spin-orbit interaction is enhanced, and the generation efficiency of the spin current with respect to the current becomes high.

[0085] The spin-orbit torque wiring 20 can also include a topological insulator. The topological insulator is a substance in which the inside is an insulator or a high-resistance body, but a metallic state in which the surface is spin-polarized is generated. The topological insulator generates an internal magnetic field by the spin-orbit interaction. The topological insulator exhibits a new topological phase by the effect of the spin-orbit interaction even without an external magnetic field. The topological insulator can efficiently generate a pure spin current by strong spin-orbit interaction and destruction of inversion symmetry at the edge.

[0086] The topological insulator is, 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, or the like. The topological insulator can efficiently generate a spin current.

[0087] Next, a manufacturing method of the magnetic device 200 will be described. The magnetic device 200 is formed by a layer-stacking process of each layer and a processing process of processing a part of each layer into a prescribed shape. The layer-stacking of each layer can use a sputtering method, a chemical vapor deposition (CVD) method, an electron beam evaporation method (EB evaporation method), an atomic laser deposition method, or the like. The processing of each layer can be performed using photolithography or the like.

[0088] Next, the manufacturing method of the vicinity of the magnetoresistive effect element 100 will be described. First, a conductive film is formed on the insulating layer and the electrodes 31, 32, and is processed into a prescribed shape, thereby forming the spin-orbit torque wiring 20. Then, the periphery of the spin-orbit torque wiring 20 is filled with an insulating layer.

[0089] Next, the upper surface of the spin-orbit torque wiring 20 is exposed by chemical mechanical polishing (CMP). Next, a magnetic layer, a non-magnetic layer, and a magnetic layer are sequentially stacked on the spin-orbit torque wiring 20 and the insulating layer. Then, a hard mask is formed at a prescribed position on the magnetic layer.

[0090] Next, the magnetic layer, the non-magnetic layer, and the magnetic layer are processed via the hard mask. The magnetic layers become the first ferromagnetic layer 1 and the second ferromagnetic layer 2, respectively, and the non-magnetic layer becomes the non-magnetic layer 3, thereby forming the laminate 10. The hard mask becomes a part of the electrode 33, for example. The first insulating layer 90 is formed so as to cover the laminate 10 and the electrode 33. Next, a conductive layer and an insulating layer are formed so as to cover the first insulating layer 90.

[0091] Next, the first insulating layer 90, the conductive layer, and a part of the insulating layer are removed by chemical mechanical polishing (CMP) to expose the electrode 33. The conductive layer on the first insulating layer 90 becomes the heat sink 40. A read line RL is formed on the electrode 33 and the insulating layer. The magnetoresistive effect element 100 shown in FIG. 1 is obtained by the above steps. Figure 6

[0092] The magnetic device 200 of the first embodiment has the heat sink 40 outside the laminate 10. The heat sink 40 is more excellent in heat dissipation than the first insulating layer 90, and dissipates heat from the vicinity of the magnetoresistive effect element 100. By dissipating heat from the vicinity of the magnetoresistive effect element 100, the magnetization stability of the first ferromagnetic layer 1 and the second ferromagnetic layer 2 is improved. In addition, it is possible to suppress heat accumulation in the spin-orbit torque wiring 20 which easily generates heat at the time of writing, and to prevent disconnection of the spin-orbit torque wiring 20 and the like.

[0093] (First Modified Example)

[0094] Figure 6 is a cross-sectional view obtained by enlarging the vicinity of the magnetoresistive effect element 101 of the magnetic device of the first modified example. In Figure 4 , the same structures as Figure 7 are denoted by the same symbols, and the description thereof will be omitted.

[0095] The heat sink 41 is provided in the vicinity of the magnetoresistive effect element 101. The heat sink 41 differs from the heat sink 40 of the first embodiment in that it is in contact with the read line RL, not the spin-orbit torque wiring 20.

[0096] ​The electrodes 31, 32, 33 are in contact with the read line RL or the via wiring V having a large heat capacity. Thus, most of the heat generated in the magnetoresistance effect element 101 is released via the electrodes 31, 32, 33. When the heat sink 40 is in contact with the read line RL, the heat accumulated in the heat sink 40 can be efficiently released from the heat sink 40 to the read line RL.

[0097] The magnetoresistance effect element 101 of the first modification example can efficiently release the generated heat like the magnetoresistance effect element 100 of the first embodiment.

[0098] (Second Modification Example)

[0099] Figure 7 is a cross-sectional view obtained by enlarging the vicinity of the magnetoresistance effect element 102 of the magnetic device of the second modification example. In Figure 4 , the same symbols are attached to the same structures as Figure 8 , and the description is omitted.

[0100] The heat sink 42 is provided in the vicinity of the magnetoresistance effect element 102. The heat sink 42 is different from the heat sink 40 of the first embodiment in that it is not in contact with the spin-orbit torque wiring 20 but is in contact with the laminate 10. The heat sink 42 is in contact with either one of the first ferromagnetic layer 1 and the second ferromagnetic layer 2 of the laminate 10. By the heat sink 42 being in contact with either one of the first ferromagnetic layer 1 and the second ferromagnetic layer 2, short-circuiting via the heat sink 42 can be prevented.

[0101] The magnetoresistance effect element 102 of the second modification example can efficiently release the generated heat like the magnetoresistance effect element 100 of the first embodiment.

[0102] (Third Modification Example)

[0103] Figure 8 is a cross-sectional view obtained by enlarging the vicinity of the magnetoresistance effect element 103 of the magnetic device of the third modification example. In Figure 4 , the same symbols are attached to the same structures as Figure 9 , and the description is omitted.

[0104] The magnetoresistance effect element 103 is different from the magnetoresistance effect element 100 of the first embodiment in the stacking order of the layers. The second ferromagnetic layer 2 is positioned closer to the substrate Sub than the first ferromagnetic layer 1 in which the magnetization direction changes. Such a magnetoresistance effect element 103 is called a bottom pinned structure. The spin-orbit torque wiring 21 is formed on the laminate 10.

[0105] The heat sink 43 extends in the x direction and sandwiches the laminate 10 in the y direction. The distance of the heat sink 43 from the laminate 11 differs depending on the position in the z direction. The distance of the heat sink 43 from the first ferromagnetic layer 1 is closer than the distance of the heat sink 43 from the second ferromagnetic layer 2. The magnetization stability of the first ferromagnetic layer 1 is lower than the magnetization stability of the second ferromagnetic layer 2. By the presence of the heat sink 43 in the vicinity of the first ferromagnetic layer 1 having low magnetization stability, the magnetic stability of the magnetoresistive effect element 103 is improved. The magnetoresistive effect element 103 stores data depending on the direction of magnetization of the first ferromagnetic layer 1, so the improvement of the magnetization stability of the first ferromagnetic layer 1 is related to the improvement of the reliability of data.

[0106] The magnetoresistive effect element 103 of the third modification example can effectively release generated heat like the magnetoresistive effect element 100 of the first embodiment.

[0107] (Fourth Modification Example)

[0108] Figure 9 is a cross-sectional view obtained by enlarging the vicinity of the magnetoresistive effect element 104 of the magnetic device of the fourth modification example. In Figure 4 , the same symbols are attached to the structures common to Figure 10 , and the explanation is omitted.

[0109] The laminate 10 of the magnetoresistive effect element 104 is continuous with the y direction side surface of the spin-orbit torque wiring 20. This structure is obtained by simultaneously processing the y direction shapes of the laminate 10 and the spin-orbit torque wiring 20.

[0110] The heat sink 44 is present in the vicinity of the magnetoresistive effect element 104. The z direction height of the heat sink 44 is, for example, higher than the sum of the heights of the spin-orbit torque wiring 20 and the laminate 10.

[0111] The magnetoresistive effect element 104 of the fourth modification example can effectively release generated heat like the magnetoresistive effect element 100 of the first embodiment.

[0112] (Fifth Modification Example)

[0113] Figure 10 is a cross-sectional view obtained by enlarging the vicinity of the magnetoresistive effect element 105 of the magnetic device of the fifth modification example. In Figure 4 , the same symbols are attached to the structures common to Figure 11 , and the explanation is omitted.

[0114] A plurality of heat sinks 45 are present in the vicinity of the magnetoresistive effect element 105. The heat sinks 45 are present toward the outside with the laminate 10 as a reference. The insulating layer and the heat sinks 45 alternately cover the side surface of the laminate 10.

[0115] The magnetic resistance effect element 105 of the fifth modification example, like the magnetic resistance effect element 100 of the first embodiment, can efficiently release generated heat. In addition, because the number of heat sinks 45 is large, the heat dissipation of the magnetic resistance effect element 105 is more excellent.

[0116] (Sixth Modification Example)

[0117] Figure 11 is a cross-sectional view obtained by enlarging the vicinity of the magnetic resistance effect element 106 of the magnetic device of the sixth modification example. In Figure 4 , the same symbols are attached to the same structures as Figure 12 , and the explanation is omitted.

[0118] The magnetic resistance effect element 106 has a space 50. The space 50 is located outside the heat sink 40 with the laminate 10 as a reference. The space 50 is in contact with the heat sink 40, for example. That is, a part of the heat sink 40 is exposed to the space 50. The space 50 is located below the read line RL, for example. The space 50 is obtained by forming a resist on the heat sink 40 and peeling off the resist after the read line RL is formed. The space 50 is in vacuum or atmosphere, and the heat insulating property is excellent.

[0119] The magnetic resistance effect element 106 of the sixth modification example, like the magnetic resistance effect element 100 of the first embodiment, can efficiently release generated heat and suppress heat transfer to surrounding elements.

[0120] The space 50 suppresses heat conduction from the heat sink 40 to the surroundings. Therefore, heat generated by the magnetic resistance effect element 106 goes toward the z direction after reaching the heat sink 40. That is, the magnetic resistance effect element 106 of the sixth modification example can control the flow of heat.

[0121] (Seventh Modification Example)

[0122] Figure 12 is a cross-sectional view obtained by enlarging the vicinity of the magnetic resistance effect element 107 of the magnetic device of the seventh modification example. In Figure 11 , the same symbols are attached to the same structures as Figure 13 , and the explanation is omitted.

[0123] The magnetic resistance effect element 107 has a space 51. The space 51 is located outside the heat sink 40 with the laminate 10 as a reference. Unlike the sixth modification example, the space 51 is not in contact with the heat sink 40.

[0124] The magnetic resistance effect element 107 of the seventh modification example can obtain the same effect as the sixth modification example. In addition, by covering the heat sink 40 with the insulator In, it is possible to prevent the heat sink 40 from being peeled off by accident.

[0125] (Second Embodiment)

[0126] Figure 13 is a cross-sectional view obtained by enlarging the vicinity of the magnetoresistive effect element 110 of the magnetic device of the second embodiment. Figure 4 The structure of the magnetoresistive effect element 110 of Figure 14 is different from that of the first embodiment.

[0127] The magnetoresistive effect element 110 of the second embodiment is composed of a laminate 12. The laminate 12 is composed of a first ferromagnetic layer 4, a second ferromagnetic layer 5, and a nonmagnetic layer 6. The nonmagnetic layer 6 is located between the first ferromagnetic layer 4 and the second ferromagnetic layer 5.

[0128] The first ferromagnetic layer 4 has a magnetic domain wall DW. The resistance value of the magnetoresistive effect element 110 varies depending on the position of the magnetic domain wall DW. The magnetoresistive effect element 110 is sometimes referred to as a magnetic domain wall moving element.

[0129] The magnetoresistive effect element 110 is covered with an insulator In. A heat sink 46 is provided outside the outer side surface of the laminate 12.

[0130] The magnetic device of the second embodiment is different from the magnetic device 200 of the first embodiment only in that the magnetoresistive effect element 110 is a magnetic domain wall moving type magnetoresistive effect element, and the same effects as the magnetic device 200 of the first embodiment can be obtained.

[0131] (Third Embodiment)

[0132] Figure 15 is a schematic view of a magnetic device 220 of the third embodiment. The magnetic device 220 is provided with a plurality of magnetoresistive effect elements 120, a plurality of source lines SL, a plurality of bit lines BL, and a plurality of fourth switching elements Sw4.

[0133] The magnetoresistive effect elements 120 are arranged, for example, in a matrix shape. The magnetoresistive effect elements 120 are respectively connected to the source lines SL and the bit lines BL.

[0134] The flow of current to the magnetoresistive effect elements 120 is controlled by the fourth switching elements Sw4. The magnetoresistive effect elements 120 perform writing and reading of data by turning the fourth switching elements Sw4 ON. The magnetoresistive effect elements 120 perform writing of data using spin transfer torque by flowing current in the stacking direction. The fourth switching elements Sw4 are the same as the first switching elements Swl and the like.

[0135] Figure 16 is a cross-sectional view of the magnetic device 220 of the third embodiment. The periphery of the magnetoresistive effect element 100 and the transistor Tr is covered with an insulator In. A heat sink 47 is formed in the insulator In.

[0136] Figure 16 is a cross-sectional view obtained by enlarging the vicinity of the magnetoresistive effect element 120 of the magnetic device 220 of the third embodiment.Figure 16 is a cross section taken by cutting the xy plane of the first ferromagnetic layer 1.

[0137] The heat sink 47 surrounds the side surface of the laminate 10. ​ The heat sink 47 shown surrounds the entire circumference of the laminate 10, but can also surround a part thereof. The first insulating layer 90 is provided between the heat sink 47 and the laminate 10.

[0138] The magnetic device 220 of the third embodiment differs only in that the magnetoresistive effect element is a spin transfer type magnetoresistive effect element, and the same effects as the magnetic device 200 of the first embodiment can be obtained.

[0139] Thus far, based on the first to third embodiments, a preferred embodiment of the present application has been exemplified, but the present application is not limited to these embodiments. For example, the characteristic structures in each of the embodiments and modified examples can be applied to other embodiments.

Claims

1. A magnetic device characterized by comprising: a laminate having a first ferromagnetic layer, a second ferromagnetic layer, and a non-magnetic layer sandwiched by the first ferromagnetic layer and the second ferromagnetic layer; a first insulating layer covering a side surface of the laminate; a heat sink located outside the first insulating layer with the laminate as a reference; a wiring connected to the laminate and extending in a first direction; and an electrode connected to the laminate on a side opposite to the wiring and a readout line.

2. The magnetic device according to claim 1, wherein the heat sink is inclined with respect to the laminate direction.

3. The magnetic device according to claim 2, wherein the side surface of the laminate is inclined with respect to the laminate direction, and the inclination direction of the side surface of the laminate with respect to the laminate direction is the same as the inclination direction of the heat sink with respect to the laminate direction.

4. The magnetic device according to claim 1, further comprising a wiring connected to the laminate and extending in a first direction, wherein the heat sink is plural, the plural heat sinks respectively extend along the first direction, and the laminate is sandwiched by two of the heat sinks.

5. The magnetic device according to claim 1, wherein the heat sink surrounds the side surface of the laminate.

6. The magnetic device according to claim 1, wherein the heat sink contains microparticles having an average particle diameter of 10 nm or less.

7. The magnetic device according to claim 1, wherein the metal is any one of copper, cobalt, tungsten, tantalum, ruthenium, and aluminum.

8. The magnetic device according to claim 1, wherein the heat sink is a non-magnetic body.

9. The magnetic device according to claim 1, wherein the height of the heat sink in the laminate direction is higher than the height of the laminate.

10. The magnetic device according to claim 1, wherein the heat sink has plural toward the outside with the laminate as a reference. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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