Magnetoresistance effect element and integrated circuit

Abstract

Provided are a magnetoresistance effect element capable of inverting the magnetization of a recording layer by a small current, and an integrated circuit using the same. A magnetoresistance effect element 1 includes a layer 11 including Ru and O, a metal layer 12 provided adjacent to the layer 11 including Ru and O, a recording layer 13 including a magnetic body provided adjacent to the metal layer 12, a barrier layer 14, and a reference layer 15, the metal layer 12 including one or more metals selected from the group consisting of Pt, W, Ta, Ti, Cr, and V. The integrated circuit is composed of a plurality of magnetoresistance effect elements 1.

Description

Magnetoresistive element and integrated circuit

[0001] The present invention relates to a magnetoresistive element and an integrated circuit.

[0002] In a magnetic tunnel junction (MTJ) element, SOT-MRAM is known, which rewrites data in a recording layer using spin orbit torque (SOT) induced magnetization reversal. ２ It is known that a RuO layer is used as a wiring layer (Patent Document 1). ２ Spin conversion efficiency θ ＳＨ is 1% to 8% (Non-Patent Document 1).

[0003] WO2016 / 136190

[0004] Phys. Rev. Lett. 128, 197202 (2022)

[0005] The wiring layer is made of RuO ２ Therefore, there is a demand for a magnetoresistive element with a high spin conversion efficiency in which the magnetization of the recording layer can be reversed by passing a small current through it, and an integrated circuit using such an element.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a magnetoresistive element that has a high spin conversion efficiency and in which the magnetization of the recording layer is reversed by passing a small current through it, and an integrated circuit using the same.

[0007] The present invention has the following concept: [1] A magnetoresistive element comprising: a layer containing Ru and O, a metal layer provided adjacent to the layer containing Ru and O, a recording layer including a magnetic material provided adjacent to the metal layer, a barrier layer, and a reference layer, wherein the metal layer contains one or more metals selected from the group consisting of Pt, W, Ta, Ti, Cr, and V. [2] The magnetoresistive element according to [1], wherein the metal layer includes any one of a Pt layer, a Pt alloy layer, a Pt / Ir stacked film, a Ru / Pt stacked film, a Ti / Pt stacked film, a W layer, a W—Ta alloy layer, a Cr / W stacked film, a Cr / W—Ta alloy stacked film, a V / W stacked film, and a V / W—Ta alloy stacked film. [3] The magnetoresistive effect element according to [2], wherein the Pt layer and the magnetic body in any one of the Pt layer, the Pt alloy layer, the Pt / Ir laminated film, the Ru / Pt laminated film, and the Ti / Pt laminated film have an fcc(111) orientation. [4] The magnetoresistive effect element according to any one of [1] to [3], wherein the layer containing Ru and O is a RuO2 layer and has a random orientation. [5] The magnetoresistive effect element according to any one of [1] to [4], wherein the magnetization of the recording layer is reversed by passing a current through the metal layer and the layer containing Ru and O. [6] The magnetoresistive effect element according to any one of [1] to [5], wherein the recording layer includes a first magnetic layer adjacent to the metal layer, an insertion layer adjacent to the first magnetic layer, and a second magnetic layer adjacent to the insertion layer. [7] An integrated circuit including the magnetoresistive effect element according to any one of [1] to [6].

[0008] According to the present invention, a magnetoresistive element includes a layer containing Ru and O, a metal layer provided adjacent to the layer containing Ru and O, a recording layer including a magnetic material provided adjacent to the metal layer, a barrier layer, and a reference layer, wherein the metal layer includes one or more metals selected from the group consisting of Pt, W, Ta, Ti, Cr, and V. As a result, the magnetic field of the recording layer is reversed by passing a small current through a wiring layer including the layer containing Ru and O and the metal layer provided adjacent to the layer containing Ru and O. When an integrated circuit such as a memory device or a logic LSI includes such a magnetoresistive element, the magnetization of the recording layer is reversed by a small current.

[0009] FIG. 1 is a diagram schematically showing a magnetoresistive effect element according to a first embodiment of the present invention. FIG. 2 is a diagram schematically showing a magnetoresistive effect element according to a second embodiment of the present invention. FIG. 3A is a diagram schematically showing a magnetoresistive effect element according to a third embodiment of the present invention. FIG. 3B is a diagram schematically showing a specific configuration of the magnetoresistive effect element according to the third embodiment of the present invention. FIG. 4 is a diagram schematically showing a magnetoresistive effect element according to a fourth embodiment of the present invention. FIG. 5 is a diagram schematically showing a magnetoresistive effect element according to a fifth embodiment of the present invention. FIG. 6A is a diagram schematically showing a magnetoresistive effect element according to a sixth embodiment of the present invention. FIG. 6B is a diagram schematically showing a specific configuration of the magnetoresistive effect element according to the sixth embodiment of the present invention. FIG. 7 is a diagram schematically showing a magnetoresistive effect element according to a seventh embodiment of the present invention. FIG. 8 is a diagram schematically showing a magnetoresistive effect element according to an eighth embodiment of the present invention. FIG. 9 is a diagram schematically showing a magnetic memory device as an integrated circuit according to a ninth embodiment of the present invention. FIG. 10 is a diagram specifically showing a memory cell in FIG. 9. FIG. 11 is a diagram schematically showing a logic LSI as an integrated circuit according to a tenth embodiment of the present invention. FIG. 12 is a cross-sectional view schematically showing a sample produced in verification experiment 1. FIG. 13 is a cross-sectional view schematically showing a sample produced in verification experiment 3. FIG. 14 is a cross-sectional view schematically showing a sample produced in verification experiment 4. FIG. 15 is a cross-sectional view schematically showing a sample produced in verification experiment 6. FIG. 16 shows the results of X-ray diffraction (XRD) of the sample produced in verification experiment 1. FIG. 17 is a cross-sectional TEM image of the sample produced in verification experiment 1. FIG. 18 shows the RuO of the sample produced in verification experiment 1. ２ 19 shows the X-ray diffraction (XRD) results of some samples prepared in Verification Experiments 2 to 4. FIG. 20 shows the cross-sectional TED images of the Pt / Pt / Co / Ir. Ｐｔ When an external magnetic field H (mT) is applied to a sample with a ｘｙ FIG. 21 shows the measurement results of the thickness t of Pt in the verification experiment 5. Ｐｔ When an external magnetic field H (mT) is applied to a sample with a ｘｙ22 shows the measurement results of R (Ohm) when an external magnetic field H (mT) is applied to a sample having a total film thickness of 4.6 nm, in which a 1.0 nm Pt layer and a 0.8 nm Ir layer are repeatedly stacked 2.5 times. ｘｙ 23 shows the measurement results of R (Ohm) when an external magnetic field H (mT) is applied to a sample having a 10 nm RuO2 layer, a 5 nm Ru layer, a 2 nm Pt layer, a 1.1 nm Co layer, a 0.5 nm Ir layer, a 1.5 nm MgO layer, and a 1.5 nm Ta layer stacked on a substrate in Verification Experiment 7. ｘｙ FIG. 24 shows the results of measuring the thickness t Ｔｉ When an external magnetic field H (mT) is applied to a sample with a ｘｙ FIG. 25 shows the measurement results of the thickness t of Ti in the verification experiment 8. Ｔｉ When an external magnetic field H (mT) is applied to a sample with a ｘｙ 26 is a graph showing the dependence of conductance on the thickness of the Pt layer or the thickness of the laminated film of the Pt layer and the Ir layer in Verification Experiment 9. FIG. 27 is a graph showing the dependence of conductance on the thickness of the RuO ２ Layer thickness t ＲｕＯ２ 28 shows the dependence of RuO ２ 29 shows the external magnetic field dependence of the efficiency χ of the effective magnetic field by SOT for Pt / Co / Ir. FIG. 29 shows the external magnetic field dependence of the efficiency χ of the effective magnetic field by SOT for Pt / Co / Ir for Verification Experiment 11. FIG. 30 shows the external magnetic field dependence of the spin conversion efficiency (spin Hall angle) θ for Verification Experiment 12. ＳＨ RuO ２ / Pt / Co / Ir Pt layer thickness t Ｐｔ , RuO ２ / [Pt / Ir] ｎ / Co / Ir [Pt / Ir] ｎ 31 is a graph showing the dependence of the layer thickness t on the spin conversion efficiency (spin Hall angle) θ ＳＨ RuO ２ / Ti / Pt / Co / Ir Ti layer thickness t Ｔｉ, RuO ２ / Ru / Pt / Co / Ir Ru layer thickness t Ｒｕ 32 shows the dependence of R ｘｙ Regarding the pulse current dependence of (Ω), during the measurement, the pulse current I was applied for 200 μs, and a constant external magnetic field H ｅｘ 33 shows the results when a pulse current of ±35 mA was repeatedly applied in the absence of a magnetic field to a sample having a 2 nm Pt layer, in verification experiment 14. ｘｙ FIG. 34 is a cross-sectional view showing a schematic diagram of a sample prepared in Verification Experiment 14. FIG. 35 shows the results of X-ray diffraction (XRD) of a plurality of samples prepared in Verification Experiment 14. FIG. 36A shows the results of X-ray diffraction (XRD) of the W layer as a function of the film thickness t Ｗ 36B shows the MH curves of each sample with the W layer thickness t Ｗ 36C shows the MH curves of each sample with the W layer thickness t Ｗ 36D shows the MH curves of each sample with the W layer thickness t Ｗ 37 shows the MH curves of each sample with a thickness of 4 nm. Ｗ 38A is a graph showing the dependence of the W layer thickness t Ｗ The Hall resistance R when an external magnetic field H (mT) is applied to a sample with a ｘｙ 38B is a diagram showing the measurement results of the W layer thickness t Ｗ The Hall resistance R when an external magnetic field H (mT) is applied to a sample with a diameter of 2 nm ｘｙ FIG. 39 is a cross-sectional view showing a schematic diagram of a sample prepared in Verification Experiment 15. FIG. 40 shows the results of X-ray diffraction (XRD) of a plurality of samples prepared in Verification Experiment 15. FIG. 41A shows the results of X-ray diffraction (XRD) of the WTa layer in Verification Experiment 15. ＷＴａ41B shows the MH curve of the sample with the thickness t of the WTa layer set to 1.44 nm in Verification Experiment 15. ＷＴａ 41C shows the MH curve of the sample with the thickness t of the WTa layer set to 1.92 nm in Verification Experiment 15. ＷＴａ 41D shows the MH curve of the sample with the thickness t of the WTa layer set to 2.4 nm in Verification Experiment 15. ＷＴａ 41E shows the MH curve of the sample with the thickness t of the WTa layer set to 3.84 nm in Verification Experiment 15. ＷＴａ 41F shows the MH curve of the sample with the thickness t of the WTa layer set to 5.76 nm in Verification Experiment 15. ＷＴａ 42 shows the dependence of conductance on the thickness of the WTa layer in Verification Experiment 15. FIG. 43A shows the dependence of conductance on the thickness of the WTa layer in Verification Experiment 15. ＷＴａ 43B is a graph showing the measurement results of the Hall resistance Rxy (Ohm) when an external magnetic field H (mT) is applied to a sample having a thickness t of 1.44 nm in the WTa layer in Verification Experiment 15. ＷＴａ 43C is a graph showing the measurement results of the Hall resistance Rxy (Ohm) when an external magnetic field H (mT) is applied to a sample having a thickness t of 2.4 nm in the WTa layer in Verification Experiment 15. ＷＴａ 43D is a graph showing the measurement results of the Hall resistance Rxy (Ohm) when an external magnetic field H (mT) is applied to a sample having a thickness t of 3.84 nm in the WTa layer in Verification Experiment 15. ＷＴａ 44 shows the measurement results of the Hall resistance Rxy (Ohm) when an external magnetic field H (mT) is applied to a sample having a spin conversion efficiency θ of 5.76 nm for Verification Experiments 14 and 15. ＳＨ RuO ２ / W / CFB / W layer thickness t Ｗ , RuO ２ / WTa / CFB / WTa layer thickness t ＷＴａ45 is a cross-sectional view schematically showing a sample prepared in verification experiment 16. FIG. 46 is a cross-sectional view schematically showing a sample prepared in verification experiment 17. FIG. 47 is a view showing the dependence of conductance on the thickness of the Cr layer and the V layer for verification experiments 16 and 17. FIG. 48 is a view showing the dependence of spin conversion efficiency θ ＳＨ RuO ２ / WTa / Cr / CFB system Cr layer thickness t Ｃｒ , RuO ２ / WTa / V / CFB system V layer thickness t Ｖ 49A is a graph showing the dependence of RuO for Verification Experiments 14 and 15. ２ / W / CFB series, RuO ２ 49B shows the dependence of the spin Hall conductivity of the RuO / WTa / CFB system on the thickness of W and WTa. ２ / WTa / Cr / CFB system, RuO ２ 1 shows the dependence of the spin Hall conductivity of the / WTa / V / CFB system on the thickness of Cr and V. 2 shows a representative electron microscope image and its trace of the device (Hall bar) created in the demonstration experiment.

[0010] Hereinafter, several embodiments of the present invention will be described in detail with reference to the drawings. The matters described in the embodiments of the present invention can be appropriately modified in design without changing the scope of the present invention.

[0011] 1 is a diagram schematically illustrating a magnetoresistive effect element according to a first embodiment of the present invention. The magnetoresistive effect element 1 according to the first embodiment of the present invention includes a substrate 10, a layer 11 containing Ru (ruthenium) and O (oxygen), a metal layer 12 provided adjacent to the layer 11 containing Ru and O, a recording layer 13 including a magnetic material provided adjacent to the metal layer 12, a barrier layer (tunnel barrier layer) 14, and a reference layer 15. The metal layer 12 contains one or more metals selected from the group consisting of Pt, W, Ta, Ti, Cr, and V. The layers are formed in the above order.

[0012] The metal layer 12 is composed of one or more metals selected from the group consisting of Pt, W, Ta, Ti, Cr, and V. The metal layer 12 may be not only a metal but also an alloy. The metal layer 12 is provided on the layer 11 containing Ru and O, on the side opposite to the substrate 10.

[0013] The metal layer 12 may be composed of one layer or multiple layers.

[0014] When the metal layer 12 is composed of a single layer, it is a layer made of either Pt or W or an alloy thereof, and is composed of, for example, a Pt layer, a Pt alloy layer, a W layer, or a W alloy layer (including a W-Ta alloy).

[0015] When the metal layer 12 is composed of multiple layers, i.e., a laminated film, it is preferably selected from the group consisting of a laminated film of a Pt layer and an Ir layer, a laminated film of a Ru layer and a Pt layer, a laminated film of a Ti layer and a Pt layer, a laminated film of a W layer, a laminated film of a Cr layer and a W layer, a laminated film of a Cr layer and a W-Ta alloy layer, a laminated film of a V layer and a W layer, and a laminated film of a V layer and a W-Ta alloy layer. The laminated film exemplified here, for example, a "laminated film of a Pt layer and an Ir layer," indicates that a Pt layer and an Ir layer are laminated in this order on a layer 11 containing Ru and O. In other words, the laminated film of a Pt layer and an Ir layer has a laminated structure of a Pt layer and an Ir layer. The same applies to the notation other than the laminated film of a Pt layer and an Ir layer. Here, the number of layers may be selected arbitrarily.

[0016] The substrate 10 is a high-resistance substrate, and may be, for example, a Si substrate and a SiO 2 film formed on the Si substrate. ２ It consists of layers.

[0017] The layer 11 containing Ru and O may contain Ru and O. The layer 11 containing Ru and O may be, for example, RuO ２ RuO ２ The layers may be randomly oriented, i.e., polycrystalline.

[0018] Specific forms of the metal layer 12 and the recording layer 13 will be described below.

[0019] In a first specific embodiment, the metal layer 12 is one selected from a Pt layer, a Pt alloy layer, a Pt / Ir laminated film, a Ru / Pt laminated film, and a Ti / Pt laminated film. Here, the "Pt / Ir laminated film" refers to a layer in which a Pt layer and an Ir layer are laminated in this order, and the number of repetitions of the Pt layer and the Ir layer can be selected arbitrarily.

[0020] The recording layer 13 includes a first magnetic layer adjacent to the metal layer 12, an insertion layer adjacent to the first magnetic layer, and a second magnetic layer adjacent to the insertion layer. The recording layer 13 is, for example, composed of a Co layer / insertion layer / CoFeB layer. Here, " / " indicates that the layer after the slash is stacked on top of the layer before the slash. The CoFeB layer is merely an example, and other layers may be used. The insertion layer is composed of a layer containing one or more metals selected from the group consisting of Mo, Ta, W, and Ir.

[0021] In a second specific embodiment, the metal layer 12 is selected from a W layer, a W—Ta alloy layer, a Cr / W—Ta alloy laminated film, a V / W laminated film, and a V / W—Ta alloy laminated film. The number of repetitions in the laminate is arbitrary. The recording layer 13 is composed of a CoFeB layer or the like. In other words, in the second specific embodiment, the insertion layer in the first specific embodiment is not necessary.

[0022] In a third specific embodiment, the metal layer 12 is one selected from a Pt layer, a Pt alloy layer, a Pt / Ir laminated film, a Ru / Pt laminated film, and a Ti / Pt laminated film. The number of repetitions of each layer is arbitrary. The recording layer 13 is composed of a layer made of an antiferromagnetic material, such as IrMn or PtMn.

[0023] In the first to third specific embodiments, it is preferable that the Pt layer, the Pt alloy layer, and the laminated film including the Pt layer (the laminated film of the Pt layer and the Ir layer, the laminated film of the Ru layer and the Pt layer, and the Pt layer in the laminated film of the Ti layer and the Pt layer) constituting the metal layer 12 all have an fcc(111) orientation. In this case, it is preferable that the magnetic material provided adjacent to the metal layer 12 in the recording layer 13 has an fcc(111) orientation.

[0024] In the magnetoresistive element 1 according to the first embodiment of the present invention, the wiring layer 16 is composed of a layer 11 containing Ru and O and a metal layer 12 provided adjacent to the layer 11 containing Ru and O. The layer 11 containing Ru and O is configured as a first layer (lower layer), and the metal layer 12 is configured as a second layer (upper layer). Here, the "upper layer" refers to a layer adjacent to the recording layer 13. The magnetoresistive element 1 is configured as an SOT-MRAM that reverses the direction of magnetization of the recording layer 13 using spin orbit torque (SOT) induced magnetization reversal. The metal layer 12 (second layer) is provided between the layer 11 containing Ru and O and the recording layer 13.

[0025] As shown in FIG. 1 , the magnetoresistive effect element 1 according to the first embodiment of the present invention is composed of a wiring layer 16 (Ru and O-containing layer 11 / metal layer 12), a recording layer 13, a barrier layer (tunnel barrier layer) 14, and a reference layer 15. The wiring layer 16 has a rectangular plate shape when viewed in the thickness direction, while the recording layer 13, the barrier layer (tunnel barrier layer) 14, and the reference layer 15 have, for example, a cylindrical shape. However, in reality, when a rectangular plate-shaped micro-element is fabricated by microfabrication, an elliptical plate shape is formed. A first transistor Tr1 is connected to one end of the wiring layer 16, and the other end of the wiring layer 16 is connected to, for example, ground via a second transistor (not shown) as necessary. A third transistor Tr3 is connected to the reference layer 15.

[0026] The third transistor Tr3 is turned OFF, and the first transistor Tr1 and the second transistor Tr2 are both turned ON, and the write voltage V Ｗ A current I is passed through the wiring layer 16. Then, a current flows through the layer 11 containing Ru and O and the metal layer 12, and the magnetization of the recording layer 13 is reversed by spin-orbit torque.

[0027] The first transistor Tr1 is turned OFF, and the second transistor Tr3 and the third transistor Tr3 are both turned ON, and the read voltage V Ｒｅａｄ current flows through wiring layer 16, recording layer 13, barrier layer (tunnel barrier layer) 14, and reference layer 15. The current is detected, and based on the magnitude relationship of the current, it is determined whether the direction of magnetization in recording layer 13 is parallel or antiparallel to the magnetization in reference layer 15.

[0028] 2 is a diagram schematically illustrating a magnetoresistive effect element according to a second embodiment of the present invention. The magnetoresistive effect element 1 according to the second embodiment of the present invention includes, on a substrate 10, a layer 11 containing Ru and O, a metal layer 12 provided adjacent to the layer 11 containing Ru and O, a recording layer 13 provided adjacent to the metal layer 12 and containing a magnetic material, a barrier layer (tunnel barrier layer) 14, and a reference layer 15. The metal layer 12 contains one or more metals (including alloys) selected from the group consisting of Pt, W, Ta, Ti, Cr, and V.

[0029] In the second embodiment, differences from the first embodiment will be explained, and since the rest is the same as the first embodiment, redundant explanations will be avoided.

[0030] As shown in FIG. 2 , the magnetoresistive element 1 according to the second embodiment of the present invention is composed of a layer 11 containing Ru and O, a metal layer 12, a recording layer 13, a barrier layer (tunnel barrier layer) 14, and a reference layer 15. The layer 11 containing Ru and O, the metal layer 12, and the recording layer 13 are rectangular plate-shaped as shown schematically in FIG. 2 . In reality, when a rectangular plate-shaped micro-element is fabricated by microfabrication, an elliptical plate-shaped element is formed. The recording layer 13 has the same rectangular shape as the metal layer 12 in the thickness direction as shown schematically in FIG. 2 , but in reality, it is elliptical due to microfabrication. When the recording layer 13, the barrier layer 14, and the reference layer 15 are smaller than the metal layer 12 in the thickness direction as in the first embodiment, the thermal stability deteriorates as the magnetoresistive element 1 itself is further miniaturized. For example, when a CoFeB material having perpendicular magnetic anisotropy is used as the recording layer, if the recording layer 13, barrier layer 14, and reference layer 15 have the same shape as seen in the thickness direction, for example, a diameter of 30 nm or less, as in the first embodiment, the thermal stability deteriorates. As in the second embodiment, if the recording layer 13 has the same shape as the Ru- and O-containing layer 11 and the metal layer 12 as seen in the thickness direction, for example, a rectangular shape as shown schematically in FIG. 2 (in reality, it becomes an elliptical shape through microfabrication), the volume of the recording layer 13 increases, so even if the magnetoresistive element 1 itself is miniaturized, the thermal stability does not deteriorate. As shown in FIG. 2, at least a portion of the barrier layer (tunnel barrier layer) 14 and the reference layer 15 have a cylindrical shape. As an example, the Ru- and O-containing layer 11 and the metal layer 12 have a rectangular shape as seen in the thickness direction (in reality, an elliptical shape) as shown schematically in FIG. 2, and the recording layer 13 has the same shape as the metal layer 12 as seen in the thickness direction. The barrier layer 14 is composed of a portion 14a having a rectangular shape (actually an elliptical shape) as shown in Fig. 2, which is the same shape as the recording layer 13 when viewed in the thickness direction, and a portion 14b having a cylindrical shape. When viewed in the thickness direction of the layer 11 containing Ru and O, the metal layer 12, and the recording layer 13, the portion 14b has dimensions smaller than the rectangular shape (actually an elliptical shape) as shown in Fig. 2.

[0031] The barrier layer 14 is composed of an MgO layer, an MgAlO layer, or the like.

[0032] 3A is a diagram schematically illustrating a magnetoresistive effect element according to a third embodiment of the present invention. The third embodiment is a specific example of the first embodiment. As shown in FIG. 3A, the reference layer 15 is configured by sandwiching a first ferromagnetic laminated film 15a and a second ferromagnetic laminated film 15c with an interlayer exchange coupling layer 15b.

[0033] In the magnetoresistive element 1 according to the third embodiment of the present invention, like the first specific form of the metal layer 12 and recording layer 13 in the first embodiment, the metal layer 12 is one selected from a Pt layer, a Pt alloy layer, a Pt / Ir laminated film, a Ru / Pt laminated film, and a Ti / Pt laminated film. Here, the "Pt / Ir laminated film" means that a Pt layer and an Ir layer are laminated in this order, and the number of repetitions of the Pt layer and the Ir layer can be selected arbitrarily. The same applies to other laminated films.

[0034] The recording layer 13 includes a first magnetic layer adjacent to the metal layer 12, an insertion layer adjacent to the first magnetic layer, and a second magnetic layer adjacent to the insertion layer. The recording layer 13 includes, for example, a Co layer 13c, an insertion layer 13b, and a CoFeB layer 13a. The CoFeB layer is merely an example, and other layers such as an FeB layer may also be used. The insertion layer 13b includes a layer containing one or more metals selected from the group consisting of Mo, Ta, W, and Ir.

[0035] The barrier layer 14 is composed of an MgO layer, an MgAlO layer, or the like.

[0036] 3B is a diagram showing a specific configuration of a magnetoresistive element according to a third embodiment of the present invention. The reference layer 15 is composed of a CoFeB layer 15d, an insertion layer 15e, a first ferromagnetic laminated film 15a, an interlayer exchange coupling layer 15b, and a second ferromagnetic laminated film 15c. The CoFeB layer 15d and the insertion layer 15e correspond to the insertion layer 13b and the CoFeB layer 13a of the metal layer 12.

[0037] The first ferromagnetic laminated film 15a is, for example, a laminated film of Co layers and Pt layers, and the number of layers can be any number. The interlayer exchange coupling layer 15b is, for example, composed of Ir layers, Ru layers, and IrRe alloy layers. The second ferromagnetic laminated film 15c is, for example, a laminated film of Co layers and Pt layers, and the number of layers can be any number.

[0038] A cap layer 17 is provided on the reference layer 15 and is connected to the third transistor Tr3 via a terminal T3. Terminals T1 and T2 are connected to both ends of the wiring layer 16, with the first transistor Tr1 connected to the terminal T1 and the terminal T2 connected to ground via a second transistor (not shown) as needed.

[0039] <Fourth Embodiment> Fig. 4 is a diagram schematically showing a magnetoresistive effect element according to a fourth embodiment of the present invention. The fourth embodiment is a specific example of the first embodiment. As shown in Fig. 4, the reference layer 15 is composed of a first ferromagnetic laminated film 15a, a second ferromagnetic laminated film 15c, and an interlayer exchange coupling layer 15b sandwiched between them.

[0040] In the magnetoresistive element 1 according to the fourth embodiment of the present invention, like the second specific form of the metal layer 12 and recording layer 13 in the first embodiment, the metal layer 12 is selected from a W layer, a W—Ta alloy layer, a Cr / W—Ta alloy laminated film, a V / W laminated film, and a V / W—Ta alloy laminated film. The number of repetitions in the laminate is arbitrary. The recording layer 13 is composed of a CoFeB layer or the like.

[0041] The barrier layer 14 is composed of an MgO layer, an MgAlO layer, etc. The reference layer 15 is composed of a CoFeB layer 15d, an insertion layer 15e, a first ferromagnetic laminated film 15a, an interlayer exchange coupling layer 15b, and a second ferromagnetic laminated film 15c. The insertion layer 15e is composed of a layer containing one or more metals selected from the group consisting of Mo, Ta, W, and Ir.

[0042] The first ferromagnetic laminated film 15a is, for example, a laminated film of Co layers and Pt layers, and the number of layers can be any number. The interlayer exchange coupling layer 15b is, for example, composed of Ir layers, Ru layers, and IrRe alloy layers. The second ferromagnetic laminated film 15c is, for example, a laminated film of Co layers and Pt layers, and the number of layers can be any number.

[0043] A cap layer 17 is provided on the reference layer 15 and is connected to the third transistor Tr3 via a terminal T3. Terminals T1 and T2 are connected to both ends of the wiring layer 16, with the first transistor Tr1 connected to the terminal T1 and the terminal T2 connected to ground via a second transistor (not shown) as needed.

[0044] <Fifth Embodiment> Fig. 5 is a diagram schematically showing a magnetoresistive effect element according to a fifth embodiment of the present invention. The fifth embodiment is a specific form of the first embodiment. In the magnetoresistive effect element 1 according to the fifth embodiment of the present invention, like the third specific form of the metal layer 12 and recording layer 13 in the first embodiment, the metal layer 12 is one selected from a Pt layer, a Pt alloy layer, a Pt / Ir laminated film, a Ru / Pt laminated film, and a Ti / Pt laminated film. The number of repetitions of each layer is arbitrary.

[0045] The recording layer 13 is made of an antiferromagnetic material, and examples of the antiferromagnetic material include IrMn and PtMn.

[0046] The barrier layer 14 is composed of an MgO layer, an MgAlO layer, etc. The reference layer 15 is composed of a layer made of an antiferromagnetic material, and examples of the antiferromagnetic material include IrMn and PtMn.

[0047] A cap layer 17 is provided on the reference layer 15 and is connected to the third transistor Tr3 via a terminal T3. Terminals T1 and T2 are connected to both ends of the wiring layer 16, with the first transistor Tr1 connected to the terminal T1 and the terminal T2 connected to ground via a second transistor (not shown) as needed.

[0048] Sixth Embodiment FIG. 6A is a schematic diagram illustrating a magnetoresistive effect element according to a sixth embodiment of the present invention. The sixth embodiment is a specific example of the second embodiment. As shown in FIG. 6A, the magnetoresistive effect element 1 according to the sixth embodiment of the present invention is composed of a layer 11 containing Ru and O, a metal layer 12, a recording layer 13, a barrier layer (tunnel barrier layer) 14, and a reference layer 15. The layer 11 containing Ru and O, the metal layer 12, and the recording layer 13 are rectangular plate-shaped as shown in FIG. 6A, but are actually formed into elliptical plate-shaped structures by microfabrication. As described above, when the magnetoresistive effect element 1 itself is miniaturized so that the recording layer 13 has the same shape as the layer 11 containing Ru and O and the metal layer 12 when viewed in the thickness direction, for example, a rectangular shape (actually an elliptical shape) as shown in FIG. 6A, thermal stability is not impaired. As shown in FIG. 6A, at least a portion of the barrier layer (tunnel barrier layer) 14 / reference layer 15 has a cylindrical shape. As an example, the layer 11 containing Ru and O and the metal layer 12 have a rectangular shape (actually an elliptical shape) when viewed in the thickness direction as shown in Fig. 6A, and the recording layer 13 has the same shape as the metal layer 12 when viewed in the thickness direction. The barrier layer 14 is made up of a portion 14a having a rectangular shape (actually an elliptical shape) as shown schematically in Fig. 6A, which has the same shape as the recording layer 13 when viewed in the thickness direction, and a portion 14b having a cylindrical shape. The portion 14b has dimensions smaller than the rectangular shape (actually an elliptical shape) of the layer 11 containing Ru and O, the metal layer 12, and the recording layer 13 when viewed in the thickness direction as shown schematically in Fig. 6A.

[0049] As shown in FIG. 6A, the reference layer 15 is configured by sandwiching a first ferromagnetic laminated film 15a and a second ferromagnetic laminated film 15c with an exchange coupling layer 15b between the layers.

[0050] In the magnetoresistive effect element 1 according to the sixth embodiment of the present invention, as in the first specific form of the metal layer 12 and the recording layer 13, the metal layer 12 is one selected from a Pt layer, a Pt alloy layer, a Pt / Ir laminated film, a Ru / Pt laminated film, and a Ti / Pt laminated film. Here, the "Pt / Ir laminated film" means that a Pt layer and an Ir layer are laminated in this order. The number of repetitions of the Pt layer and the It layer is selected arbitrarily. The same applies to other laminated layers.

[0051] The recording layer 13 includes a first magnetic layer adjacent to the metal layer 12, an insertion layer adjacent to the first magnetic layer, and a second magnetic layer adjacent to the insertion layer. The recording layer 13 includes, for example, a Co layer 13c, an insertion layer 13b, and a CoFeB layer 13a. The CoFeB layer is merely an example, and other layers may be used. The insertion layer 13b includes one or more metals selected from the group consisting of Mo, Ta, W, and Ir.

[0052] The barrier layer 14 is composed of an MgO layer, an MgAlO layer, etc. The wiring layer 16 is composed of a layer 11 containing Ru and O and a metal layer 12, and may include a recording layer 13.

[0053] 6B is a diagram showing a specific configuration of a magnetoresistive element according to a sixth embodiment of the present invention. The reference layer 15 is composed of a CoFeB layer 15d, an insertion layer 15e, a first ferromagnetic laminated film 15a, an interlayer exchange coupling layer 15b, and a second ferromagnetic laminated film 15c. The CoFeB layer 15d and the insertion layer 15e correspond to the insertion layer 13b and the CoFeB layer 13a of the metal layer 12.

[0054] The first ferromagnetic laminated film 15a is, for example, a laminated film of Co layers and Pt layers, and the number of layers can be any number. The interlayer exchange coupling layer 15b is, for example, composed of Ir layers, Ru layers, and IrRe alloy layers. The second ferromagnetic laminated film 15c is, for example, a laminated film of Co layers and Pt layers, and the number of layers can be any number.

[0055] A cap layer 17 is provided on the reference layer 15 and is connected to the third transistor Tr3 via a terminal T3. Terminals T1 and T2 are connected to both ends of the wiring layer 16, with the first transistor Tr1 connected to the terminal T1 and the terminal T2 connected to ground via a second transistor (not shown) as needed.

[0056] Seventh Embodiment FIG. 7 is a schematic diagram illustrating a magnetoresistive effect element according to a seventh embodiment of the present invention. The seventh embodiment is a specific example of the second embodiment. As shown in FIG. 7, the magnetoresistive effect element 1 according to the seventh embodiment of the present invention is composed of a layer 11 containing Ru and O, a metal layer 12, a recording layer 13, a barrier layer (tunnel barrier layer) 14, and a reference layer 15. The layer 11 containing Ru and O, the metal layer 12, and the recording layer 13 are rectangular plate-shaped (actually elliptical) as shown schematically in FIG. 7. The magnetoresistive effect element 1 itself is miniaturized so that the recording layer 13 has the same shape as the layer 11 containing Ru and O and the metal layer 12 when viewed in the thickness direction, for example, a rectangular shape (actually an elliptical shape) as shown schematically in FIG. 7, thereby preventing an increase in volume and a deterioration in thermal stability. As shown in FIG. 7, at least a portion of the barrier layer (tunnel barrier layer) 14 / reference layer 15 has a cylindrical shape. As an example, the layer 11 containing Ru and O and the metal layer 12 have a rectangular shape (actually an elliptical shape) when viewed in the thickness direction as shown schematically in Fig. 7, and the recording layer 13 has the same shape as the metal layer 12 when viewed in the thickness direction. The barrier layer 14 is made up of a portion 14a having a rectangular shape (actually an elliptical shape) as shown schematically in Fig. 7, which has the same shape as the recording layer 13 when viewed in the thickness direction, and a portion 14b having a cylindrical shape. The portion 14b has dimensions smaller than the rectangular shapes (actually an elliptical shape) of the layer 11 containing Ru and O, the metal layer 12, and the recording layer 13 when viewed in the thickness direction.

[0057] As shown in FIG. 7, the reference layer 15 is configured by sandwiching a first ferromagnetic laminated film 15a and a second ferromagnetic laminated film 15c with an exchange coupling layer 15b between the films.

[0058] In the magnetoresistive element 1 according to the seventh embodiment of the present invention, as in the second specific example of the metal layer 12 and the recording layer 13, the metal layer 12 is selected from a W layer, a W—Ta alloy layer, a Cr / W—Ta alloy laminated film, a V / W laminated film, and a V / W—Ta alloy laminated film. The number of repetitions in the laminate is arbitrary. The recording layer 13 is composed of a CoFeB layer or the like.

[0059] The barrier layer 14 is composed of an MgO layer, an MgAlO layer, etc. The wiring layer 16 is composed of a layer 11 containing Ru and O and a metal layer 12, and may include a recording layer 13.

[0060] The reference layer 15 is composed of a CoFeB layer 15d, an insertion layer 15e, a first ferromagnetic laminated film 15a, an interlayer exchange coupling layer 15b, and a second ferromagnetic laminated film 15c. The insertion layer 15e is composed of a layer containing one or more metals selected from the group consisting of Mo, Ta, W, and Ir.

[0061] The first ferromagnetic laminated film 15a is, for example, a laminated film of Co layers and Pt layers, and the number of layers can be any number. The interlayer exchange coupling layer 15b is, for example, composed of Ir layers, Ru layers, and IrRe alloy layers. The second ferromagnetic laminated film 15c is, for example, a laminated film of Co layers and Pt layers, and the number of layers can be any number.

[0062] A cap layer 17 is provided on the reference layer 15 and is connected to the third transistor Tr3 via a terminal T3. Terminals T1 and T2 are connected to both ends of the wiring layer 16, with the first transistor Tr1 connected to the terminal T1 and the terminal T2 connected to ground via a second transistor (not shown) as needed.

[0063] Eighth Embodiment FIG. 8 is a schematic diagram illustrating a magnetoresistive effect element according to an eighth embodiment of the present invention. The eighth embodiment is a specific example of the second embodiment. As shown in FIG. 8, the magnetoresistive effect element 1 according to the eighth embodiment of the present invention is composed of a layer 11 containing Ru and O, a metal layer 12, a recording layer 13, a barrier layer (tunnel barrier layer) 14, and a reference layer 15. The layer 11 containing Ru and O, the metal layer 12, and the recording layer 13 are rectangular plate-shaped (actually elliptical) as shown schematically in FIG. 8. When the magnetoresistive effect element 1 itself is miniaturized so that the recording layer 13 has the same shape as the layer 11 containing Ru and O and the metal layer 12 when viewed in the thickness direction, for example, a rectangular shape (actually an elliptical shape) as shown schematically in FIG. 8, the volume increases, and thermal stability is not impaired. As shown in FIG. 8, at least a portion of the barrier layer (tunnel barrier layer) 14 / reference layer 15 has a cylindrical shape. As an example, the layer 11 containing Ru and O and the metal layer 12 have a rectangular shape (actually an elliptical shape) when viewed in the thickness direction as shown schematically in Fig. 8, and the recording layer 13 has the same shape as the metal layer 12 when viewed in the thickness direction. The barrier layer 14 is made up of a portion 14a having a rectangular shape (actually an elliptical shape) as shown schematically in Fig. 8, which is the same shape as the recording layer 13 when viewed in the thickness direction, and a portion 14b having a cylindrical shape. The portion 14b has dimensions smaller than the rectangular shape (actually an elliptical shape) when viewed in the thickness direction of the layer 11 containing Ru and O, the metal layer 12, and the recording layer 13, as shown schematically in Fig. 8.

[0064] In the magnetoresistive element 1 according to the eighth embodiment of the present invention, as in the third specific example of the metal layer 12 and the recording layer 13, the metal layer 12 is one selected from a Pt layer, a Pt alloy layer, a Pt / Ir laminated film, a Ru / Pt laminated film, and a Ti / Pt laminated film. The number of repetitions in the lamination is arbitrary.

[0065] The recording layer 13 is made of an antiferromagnetic material, and examples of the antiferromagnetic material include IrMn and PtMn.

[0066] The barrier layer 14 is composed of an MgO layer, an MgAlO layer, etc. The wiring layer 16 is composed of a layer 11 containing Ru and O and a metal layer 12, and may include a recording layer 13.

[0067] Reference layer 15 is made of an antiferromagnetic material, and examples of the antiferromagnetic material include IrMn and PtMn.

[0068] A cap layer 17 is provided on the reference layer 15 and is connected to the third transistor Tr3 via a terminal T3. Terminals T1 and T2 are connected to both ends of the wiring layer 16, and are connected to the first transistor Tr1 and, if necessary, to ground via a second transistor (not shown).

[0069] 9 is a diagram showing a magnetic memory device as an integrated circuit according to a ninth embodiment of the present invention. As shown in FIG. 9, the magnetic memory device 2 is configured by arranging a plurality of memory cells 20 in an array. The magnetic memory device 2 includes an X driver 21 and a Y driver 22 adjacent to the memory array, and a controller 23 controls the X driver 21 and the Y driver 22. The array of memory cells 20 is arranged in, for example, M rows and M columns. A first bit line BL1 and a second bit line BL2 of a corresponding column are connected to a memory cell, and the memory cell is connected to word lines WL1 and WL2 and a source line SL of a corresponding row. The X driver 21 and the Y driver 22 select a memory cell.

[0070] Fig. 10 is a diagram schematically showing one memory cell 20 in the magnetic memory device shown in Fig. 9. As shown in Fig. 10, the memory cell 20 is configured using a magnetoresistive effect element according to any one of the first to eighth embodiments of the present invention.

[0071] Tenth Embodiment Fig. 11 is a diagram schematically illustrating a logic LSI as an integrated circuit according to a tenth embodiment of the present invention. The logic LSI 3 includes one or more memory units 4, one or more logic units 5, peripheral circuits (not shown), and input / output circuits. At least one of the memory unit 4 and the logic unit 5 includes a magnetoresistive element according to any one of the first to eighth embodiments of the present invention. In the logic LSI 3, the memory unit 4 and the logic unit 5 do not need to be arranged in a plane as shown in Fig. 11. For example, a magnetoresistive element may be arranged on the logic unit to form a three-dimensional configuration.

[0072] While showing verification experiments, it will be explained that the magnetoresistive effect element according to each embodiment of the present invention comprises a layer 11 containing Ru and O, a metal layer 12 provided adjacent to the layer 11 containing Ru and O, a recording layer 13 including a magnetic material provided adjacent to the metal layer 12, a barrier layer (tunnel barrier layer) 14, and a reference layer 15, and that the metal layer 12 preferably includes a layer of one or more metals (including alloys) selected from the group consisting of Pt, W, Ta, Ti, Cr, and V.

[0073] <Verification Experiment 1> In verification experiment 1, as shown in FIG. 12, a 10 nm RuO ２ A sample was fabricated by stacking a 0.5 nm Ir layer, a 1.5 nm Pt layer, a 1.1 nm Co layer, a 0.5 nm Ir layer, a 1.5 nm MgO layer, and a 1.5 nm Ta layer in this order. A Si substrate with a thermal oxide film formed on it was used as the substrate. Figure 16 shows the X-ray diffraction (XRD) results for the sample fabricated in Verification Experiment 1. The horizontal axis represents 2θ, and the vertical axis represents the X-ray diffraction intensity (arbitrary scale). Here, θ is the angle of incidence of the X-rays on the atomic plane.

[0074] 16, multiple peaks of the Si substrate were observed from about 55 degrees to about 80 degrees in 2θ. A Pt(111) peak was observed at about 40 degrees in 2θ. A Pt(222) peak was observed at about 85 degrees in 2θ.

[0075] From this, Pt has a (111) orientation, and RuO ２ It was found that the diffraction peaks were consistent with the (111) and (100) diffraction peaks.

[0076] FIG. 17 is a cross-sectional TEM image of the sample prepared in Verification Experiment 1. From FIG. 17, it is clear that RuO ２ It was found that the Pt / Co / Ir is randomly oriented, i.e., polycrystalline. It was found that the Pt / Co / Ir is (111) oriented. Pt tends to grow granularly, but RuO ２ Both of the above Pt / Co / Ir films were found to be flat.

[0077] FIG. 18 shows the RuO sample prepared in Verification Experiment 1. ２ This is a cross-sectional TED image of RuO / Pt / Co / Ir. ２It was found that the Pt / Co / Ir film was randomly oriented, and the Pt / Co / Ir film was (111) oriented.

[0078] <Verification Experiment 2> In verification experiment 2, as shown in FIG. 12, a 10 nm RuO ２ A plurality of samples were fabricated by laminating a Pt layer, a Pt layer, a 1.1 nm Co layer, a 0.5 nm Ir layer, a 1.5 nm MgO layer, and a 1.5 nm Ta layer in this order. Ｐｔ The thicknesses were set to 1.5 nm, 2.0 nm, 2.5 nm, 3.0 nm, 4.0 nm, and 5.0 nm. The substrate used was a Si substrate on which a thermal oxide film was formed.

[0079] <Verification Experiment 3> In verification experiment 3, as shown in FIG. 13, a 10 nm RuO ２ A plurality of samples were fabricated by laminating a Ru layer, a 2 nm Pt layer, a 1.1 nm Co layer, a 0.5 nm Ir layer, a 1.5 nm MgO layer, and a 1.5 nm Ta layer in this order. Ｒｕ The thicknesses were set to 1.0 nm, 2.0 nm, 3.0 nm, 4.0 nm, and 5.0 nm. The substrate used was a Si substrate on which a thermal oxide film was formed.

[0080] <Verification Experiment 4> In verification experiment 4, as shown in FIG. 14, a 10 nm RuO ２ A plurality of samples were fabricated by laminating a Ti layer, a Ti layer, a 2 nm Pt layer, a 1.1 nm Co layer, a 0.5 nm Ir layer, a 1.5 nm MgO layer, and a 1.5 nm Ta layer in this order. Ｔｉ The thicknesses were set to 1.0 nm, 2.0 nm, 3.0 nm, 4.0 nm, and 5.0 nm. The substrate used was a Si substrate on which a thermal oxide film was formed.

[0081] FIG. 19 shows the X-ray diffraction (XRD) results of some of the samples prepared in Verification Experiments 2 to 4. The samples are, in order from left to right, RuO ２ XRD results of / Pt / Co / Ir, RuO ２ XRD results of Ru / Pt / Co / Ir, RuO ２ 19 shows the XRD results of RuO / Ti / Pt / Co / Ir. ２ In the XRD results of / Pt / Co / Ir, the thickness of the Pt layer t ＰｔThe figure shows two examples of samples with thicknesses of 5.0 nm and 2.5 nm. ２ In the XRD results of / Ru / Pt / Co / Ir, the thickness of the Ru layer t Ｒｕ The figure shows two examples of samples with thicknesses of 5.0 nm and 2.0 nm. ２ In the XRD results of / Ti / Pt / Co / Ir, the thickness of the Ru layer t Ｔｉ The graph shows two examples of samples with diameters of 5.0 nm and 2.0 nm. The horizontal axis is 2θ, and the vertical axis is the X-ray diffraction intensity (arbitrary scale). Here, θ is the angle of incidence of the X-ray onto the atomic plane.

[0082] In both XRD results, a diffraction peak of Pt(111) is observed at 2θ of approximately 40 degrees, indicating that RuO ２ Even if a Pt layer is formed directly on the RuO ２ Even if a Pt layer is formed on top of a Ru layer, ２ Even when a Pt layer was formed on a Ru layer, the Pt layer was found to be entirely (111) oriented. Furthermore, from all of the XRD results, it was considered that the Co and Ir layers were entirely (111) oriented, and it was revealed that Co has perpendicular magnetic anisotropy, as shown in the results below.

[0083] The Pt layer is RuO ２ When the Pt layer has a thickness of 1 nm or more, preferably 1.5 nm or more, the Pt layer has a (111) orientation. ２ When a Pt layer is provided on a layer with a Ru layer or a Ti layer interposed therebetween and the Pt layer has a thickness of 1 nm or more, preferably 1.5 nm or more, the Pt layer has a (111) orientation. Here, the Pt layer has a thickness of, for example, 5 nm or less.

[0084] <Verification Experiment 5> Each Hall bar sample was prepared in the same manner as in Verification Experiment 2, and an external magnetic field H (mT) was applied in the direction perpendicular to the film to measure the Hall resistance R ｘｙ 20 shows the relationship between the thickness t of the Pt layer and the resistance of the Pt layer in Verification Experiment 5. Ｐｔ The Hall resistance R when an external magnetic field H (mT) is applied to a sample with a ｘｙ The measurement results of (Ohm) for Verification Experiment 5 are shown in FIG.Ｐｔ The Hall resistance R when an external magnetic field H (mT) is applied to a sample with a ｘｙ The vertical axis shows the Hall resistance R ｘｙ The horizontal axis represents the external magnetic field H (mT), and the rectangular anomalous Hall curve is shown depending on the direction of the applied external magnetic field, indicating that the Co layer exhibits perpendicular magnetic anisotropy.

[0085] <Verification Experiment 6> In verification experiment 6, as shown in FIG. 15, a 10 nm RuO ２ Each Hall bar sample was fabricated by laminating a layer, a stacked film of a Pt layer and an Ir layer, a 1.1 nm Co layer, a 0.5 nm Ir layer, a 1.5 nm MgO layer, and a 1.5 nm Ta layer in this order. The laminated film of the Pt layer and the Ir layer was a laminated film of 1.0 nm Pt layer and 0.8 nm Ir layer with a total thickness of 1.8 nm, a laminated film of 1.0 nm Pt layer and 0.8 nm Ir layer laminated 1.5 times with a total thickness of 2.8 nm, a laminated film of 1.0 nm Pt layer and 0.8 nm Ir layer laminated twice with a total thickness of 3.6 nm, a laminated film of 1.0 nm Pt layer and 0.8 nm Ir layer laminated 2.5 times with a total thickness of 4.6 nm, and a laminated film of 1.0 nm Pt layer and 0.8 nm Ir layer laminated three times with a total thickness of 5.4 nm. An external magnetic field H (mT) was applied in the direction perpendicular to the film to measure the Hall resistance R ｘｙ (Ohm) was measured.

[0086] FIG. 22 shows the Hall resistance R when an external magnetic field H (mT) is applied to a sample having a total thickness of 4.6 nm, in which a 1.0 nm Pt layer and a 0.8 nm Ir layer are repeatedly stacked 2.5 times. ｘｙ The vertical axis shows the Hall resistance R ｘｙ The horizontal axis represents the external magnetic field H (mT), and the rectangular anomalous Hall curve is shown depending on the direction of the applied external magnetic field, indicating that the Co layer exhibits perpendicular magnetic anisotropy.

[0087] <Verification Experiment 7> Each Hall bar sample was prepared in the same manner as in Verification Experiment 3, and an external magnetic field H (mT) was applied in the direction perpendicular to the film to measure the Hall resistance R ｘｙ23 shows the results of Verification Experiment 7, where a 10 nm RuO ２ In a sample having a layer, a 5 nm Ru layer, a 2 nm Pt layer, a 1.1 nm Co layer, a 0.5 nm Ir layer, a 1.5 nm MgO layer, and a 1.5 nm Ta layer stacked in this order, the Hall resistance R ｘｙ The vertical axis shows the Hall resistance R ｘｙ The horizontal axis represents the external magnetic field H (mT), and the rectangular anomalous Hall curve is shown depending on the direction of the applied external magnetic field, indicating that the Co layer exhibits perpendicular magnetic anisotropy.

[0088] <Verification Experiment 8> Each Hall bar sample was prepared in the same manner as in Verification Experiment 4, and an external magnetic field H (mT) was applied in the direction perpendicular to the film to measure Rxy (Ohm). Ｔｉ The Hall resistance R when an external magnetic field H (mT) is applied to a sample with a ｘｙ The measurement results of (Ohm) are shown in FIG. 25 for the verification experiment 8. Ｔｉ The Hall resistance R when an external magnetic field H (mT) is applied to a sample with a ｘｙ The vertical axis shows the Hall resistance R ｘｙ The horizontal axis represents the external magnetic field H (mT), and the horizontal axis represents the external magnetic field H. All samples exhibited rectangular anomalous Hall curves depending on the direction of application of the external magnetic field, indicating that the Co layer exhibited perpendicular magnetic anisotropy.

[0089] <Verification Experiment 9> In each of the samples prepared in Verification Experiments 2 and 6, the conductance was measured relative to the thickness of the Pt layer or the thickness of the laminated film of Pt and Ir.

[0090] 26 is a graph showing the dependence of conductance on the thickness of the Pt layer or the thickness of the laminated film of the Pt layer and the Ir layer in Verification Experiment 9. The horizontal axis represents the thickness t Ｐｔ or the thickness t of the laminated film of the Pt layer and the Ir layer ＰｔＩｒ and the vertical axis is the conductance G ｘｘ (Ω －１ ). The circle (●) plots indicate RuO ２Conductance of RuO ２ / [Pt / Ir] ｎ The plots show the conductance of Pt / Co / Ir. Ｐｔ and the thickness t of the laminated film of the Pt layer and the Ir layer ＰｔＩｒ As increases, the conductance G ｘｘ (Ω －１ ) increases. Ｐｔ is 18.8 μΩcm, and [Pt / Ir] ｎ Layer resistivity ρ ＰｔＩｒ The resistivity was 22.0 μΩcm. It was found that the resistance was very low, making it suitable for LSI wiring. The low resistivity obtained here was due to the thin Pt layer on the Ru oxide film, [Pt / Ir] ｎ This is thought to be due to the flatness of the layer.

[0091] <Verification Experiment 10> A sample similar to the sample prepared in Verification Experiment 2 was prepared. ２ A RuO layer, a 2.5 nm Pt layer, a 1.1 nm Co layer, a 0.5 nm Ir layer, a 1.5 nm MgO layer, and a 1.5 nm Ta layer were stacked in this order to fabricate a plurality of samples. ２ Layer thickness t ＲｕＯ２ A plurality of samples were fabricated with thicknesses of 5 nm, 7 nm, 9 nm, 11 nm, 13 nm, and 15 nm. Conductance was measured for each sample.

[0092] FIG. 27 shows the results of the verification experiment 10. ２ Layer thickness t ＲｕＯ２ The horizontal axis shows the dependence of RuO ２ Layer thickness t ＲｕＯ２ The vertical axis is the conductance G ｘｘ (Ω －１ ) RuO ２ Layer thickness t ＲｕＯ２ As increases, the conductance G ｘｘ (Ω －１ ) was found to increase. ２ Layer resistivity ρ ＰｔＲｕＯ２ The resistivity of β-tungsten was 170.2 μΩcm.β－Ｗ , resistivity ρ of β-tantalum β－Ｔａ Therefore, compared with the resistivity of β-tungsten and β-tantalum, RuO ２ It was found that the specific resistance of is low among oxides, and that it exhibits metallic conductivity, making it suitable for use as wiring for LSIs.

[0093] From these results, RuO ２ has good conductivity and low resistivity for an oxide, and Pt usually grows easily into particles, which increases resistivity, but RuO ２ A flat growth was observed on the layer (see FIG. 17), and the resistivity was lower than that of the Pt layer / Ir layer stack. Therefore, the layer containing Ru and O and the metal layer according to the embodiment of the present invention are preferably a Pt layer or a [Pt / Ir] layer. ｎ It has been found that the wiring layer including the laminated film of the above is preferable as a conductive layer for SOT-MRAM (wiring for SOT-MRAM).

[0094] <Verification Experiment 11> For each sample prepared in Verification Experiment 2 and Verification Experiment 6, when an external magnetic field was applied in the direction perpendicular to the film, the efficiency χ of the effective magnetic field generated by the spin-orbit torque (SOT) was calculated, and the dependency of the efficiency χ of the effective magnetic field due to SOT on the external magnetic field was calculated. The efficiency χ of the effective magnetic field due to SOT was calculated using the following formula: χ = H ｅｆｆ / J where H ｅｆｆ is the effective magnetic field caused by the spin-orbit torque, and the external magnetic field H ｅｘ Using the angle Δφ caused by the difference in the direction of the current, H ｅｆｆ = H ｅｘ Δφ, where J is the current density.

[0095] FIG. 28 shows the results of verification experiment 11. ２ 28 shows the external magnetic field dependence of the efficiency χ of the effective magnetic field by SOT for Pt / Co / Ir. From the top to bottom in FIG. 28, the black triangle (▲) plot, the white square (□) plot, the diamond (◆) plot, the white triangle (△) plot, the black square (■) plot, and the black circle (●) plot show the dependence of the effective magnetic field efficiency χ on the Pt thickness t ＰｔThe thicknesses of Pt, t, are 1.5 nm, 2.0 nm, 2.5 nm, 3.0 nm, 4.0 nm, and 5.0 nm. As the external magnetic field increases, the effective magnetic field increases, but it can be seen that the effective magnetic field does not increase any further once it reaches a certain value. Ｐｔ It was found that the thinner the film, the greater the efficiency χ of the effective magnetic field due to the SOT.

[0096] FIG. 29 shows the results of verification experiment 11. ２ / [Pt / Ir] ｎ 29 shows the external magnetic field dependence of the SOT-induced effective magnetic field efficiency χ for [Pt / Ir]. From the top to bottom in FIG. 29, the white triangle (△) plot, white diamond (◇) plot, inverted triangle (▽) plot, white square (□) plot, and white circle (○) plot represent the external magnetic field dependence of the SOT-induced effective magnetic field efficiency χ for [Pt / Ir]. ｎ Thickness t ｐｔＩｒ The effective magnetic field increases as the external magnetic field increases, but it does not increase any further once the effective magnetic field reaches a certain value. [Pt / Ir] ｎ Thickness t ｐｔＩｒ It was found that the thinner the film, the greater the efficiency χ of the effective magnetic field due to the SOT.

[0097] 28 and 29, RuO ２ / Pt / Co / Ir, RuO ２ / [Pt / Ir] ｎ In either case of / Co / Ir, the thickness of Pt t Ｐｔ [Pt / Ir] ｎ Thickness t ｐｔＩｒ This is thought to be because, in the thin range, the orbital current generated between the oxide / nonmagnetic layer increases due to the influence of the spin Hall effect of Pt or Pt / Ir, and the efficiency χ of the effective magnetic field due to SOT increases.

[0098] Furthermore, the spin conversion efficiency (spin Hall angle) θ ＳＨ The spin conversion efficiency (spin Hall angle) θ ＳＨ was calculated using the following formula: θ ＳＨ = 8χeμ ０ M ｓ t / hcos(β) where e is the electric charge, h is Planck's constant, μ ０is the dielectric constant of a vacuum, t is the thickness of the magnetic layer, M ｓ is the saturation magnetization, β is the high external magnetic field H ｅｘ In the region, cos(β)=1 is satisfied, and it is the angle between the magnetization of the magnetic layer and the external magnetic field.

[0099] FIG. 30 shows the spin conversion efficiency (spin Hall angle) θ ＳＨ RuO ２ / Pt / Co / Ir Pt layer thickness t Ｐｔ , RuO ２ / [Pt / Ir] ｎ / Co / Ir [Pt / Ir] ｎ Layer thickness t ＰｔＩｒ The horizontal axis represents the thickness t of the Pt layer. Ｐｔ [Pt / Ir] ｎ Layer thickness t ＰｔＩｒ、 The vertical axis is the spin conversion efficiency θ ＳＨ is.

[0100] RuO ２ / Pt / Co / Ir Pt layer thickness t Ｐｔ , RuO ２ / [Pt / Ir] ｎ / Co / Ir [Pt / Ir] ｎ Layer thickness t ＰｔＩｒ When becomes small, the spin conversion efficiency (spin Hall angle) θ ＳＨ becomes larger, and the thickness of the Pt layer t Ｐｔ = 1.5 nm, thickness t of the [Pt / Ir]n layer ＰｔＩｒ = 1.8 nm, it becomes the maximum.

[0101] As mentioned above, this is because the orbital current generated between the oxide / non-magnetic layer is Pt, [Pt / Ir] ｎ This is because the spin-orbit interaction of the layers enhances the spin conversion efficiency θ ＳＨ is about 6-7%, and [Pt / Ir] ｎ Spin conversion efficiency θ in / Co / Ir ＳＨ The underlayer is made of RuO ２ The presence of the Pt layer provides high spin conversion efficiency. Ｐｔ , the thickness t of the [Pt / Ir]n layer ＰｔＩｒThe thickness t of the Pt layer is preferably within the range shown by the curve in FIG. Ｐｔ , the thickness t of the [Pt / Ir]n layer ＰｔＩｒ If the thickness of Pt and [Pt / Ir]n becomes too large, ＳＨ The value becomes close to , and the enhancement effect is weakened.

[0102] RuO ２ / Pt / Co / Ir Pt layer thickness t Ｐｔ is 0<t Ｐｔ Preferably, t≦6.5 nm. Ｐｔ ≦4 nm is particularly preferred. Ｐｔ It is known that even if Pt is 1 nm thick on Ru oxide, a flat Pt film can be obtained without island-like growth.

[0103] RuO ２ / [Pt / Ir]n / Co / Ir [Pt / Ir]n layer thickness t ＰｔＩｒ is 0<t ＰｔＩｒ Preferably, t≦6.5 nm. ＰｔＩｒ More preferably, t≦4.6 nm. ＰｔＩｒ ≦4 nm is particularly preferred. ＰｔＩｒ It is known that even if Pt / Ir is 1 nm thick on Ru oxide, a flat Pt / Ir film can be obtained without island-like growth.

[0104] <Verification Experiment 12> For each sample prepared in Verification Experiment 3 and Verification Experiment 4, the spin conversion efficiency θ due to spin-orbit torque was measured. ＳＨ FIG. 31 shows the spin conversion efficiency (spin Hall angle) θ ＳＨ RuO ２ / Ti / Pt / Co / Ir Ti layer thickness t Ｔｉ , RuO ２ / Ru / Pt / Co / Ir Ru layer thickness t Ｒｕ The horizontal axis represents the thickness t of the Ti layer. Ｔｉ , the thickness of the Ru layer t Ｒｕ、 The vertical axis is the spin conversion efficiency θ ＳＨ is.

[0105] Spin conversion efficiency (spin Hall angle) θ of Pt / Co / Ir ＳＨis about 6%-7%, and [Pt / Ir] ｎ / Co / Ir spin conversion efficiency θ ＳＨ is about 10% (see Figure 30). ２ / Ti / Pt / Co / Ir, RuO ２ By sequentially stacking a Ti layer and a Pt layer on the layer, the spin conversion efficiency (spin Hall angle) θ ＳＨ High. RuO ２ / Ru / Pt / Co / Ir, RuO ２ By stacking a Ru layer and a Pt layer in this order on the layer, the spin conversion efficiency (spin Hall angle) θ ＳＨ This indicates that the orbital current generated between the oxide and non-magnetic layer is transmitted through the Ti / Pt and Ru / Pt layers with little attenuation in the Ru and almost no attenuation in the Ti, and is enhanced in the Pt. It has become clear that there is no attenuation even when a layer made of light elements such as Ru or Ti is sandwiched between them, and the thickness of the non-magnetic layer can be increased, thereby reducing the wiring resistance, making this a preferable structure for LSI wiring.

[0106] RuO ２ / Ti / Pt / Co / Ir Ti layer thickness t Ｔｉ Even if the thickness is increased, the spin conversion efficiency θ ＳＨ does not decrease, and the thickness of the Ti layer t Ｔｉ = 0 spin conversion efficiency θ ＳＨ Even when the thickness of the Ti layer was 10 nm, the spin conversion efficiency θ ＳＨ = 19.2%, so t Ｔｉ is 0<t Ｔｉ The metal layer made of a laminated film of a Ti layer / Pt layer can obtain a large number of spin-polarized electrons even when the wiring resistance is reduced, and can significantly reduce power consumption.

[0107] RuO ２ / Ru / Pt / Co / Ir Ru layer thickness t Ｒｕ When the thickness is increased, the spin conversion efficiency θ ＳＨ It was found that the thickness of the Ru layer t Ｒｕ The thicker the Ru layer, the lower the resistance. Ｒｕ is 0<t ＲｕIt is preferable that 0<t≦5 nm. Ｒｕ It is particularly preferred that it is ≦3 nm.

[0108] RuO ２ / Ti / Pt / Co / Ir, RuO ２ In the / Ru / Pt / Co / Ir structure, the thickness of the Pt layer should be the preferred value, especially the preferred value, shown in Verification Experiment 12.

[0109] <Verification Experiment 13> For each sample prepared in Verification Experiment 2, the Hall resistance R was measured when a pulse current I was applied with a pulse width of 200 μsec with or without applying a constant external magnetic field in the direction perpendicular to the film. ｘｙ was measured.

[0110] FIG. 32 shows the R ｘｙ Regarding the pulse current dependence of (Ω), during the measurement, the pulse current I was applied for 200 μs, and a constant external magnetic field H ｅｘ The graph shows the results when applying voltages of -11 mT, -6 mT, 0 mT, 8.4 mT, and 13.7 mT, respectively. The horizontal axis represents the pulse current, and the vertical axis represents the Hall resistance R ｘｙ (Ω).

[0111] From Figure 32, it was confirmed that the magnetization was reversed by the spin-orbit torque. ｅｘ In the absence of a magnetic field, magnetization reversal due to spin-orbit torque was observed, enabling us to observe spin reversal in the absence of a magnetic field.

[0112] FIG. 33 shows the Hall resistance R when a pulse current of ±35 mA was repeatedly applied in the absence of a magnetic field to a sample having a 2 nm Pt layer in Verification Experiment 13. ｘｙ 33 shows the dependence of the magnetization reversal on the number of repetitions (Ω). It can be seen from FIG. 33 that stable magnetization reversal occurs even when a pulse current of ±35 mA is repeatedly applied. Ｐｔ is 1.0≦t Ｐｔ ≦2.5 nm, and 1.5≦t Ｐｔ More preferably, t Ｐｔ It is more preferable that the thickness is ≦2.2 nm.

[0113] From the above-described multiple verification results, RuO ２ In contrast to the low spin conversion efficiency of an SOT element using a layer as a wiring layer, the following was found by using a stack of a layer containing Ru and O and a metal layer as a wiring layer. ２ The orbital current generated between the layer and the metal layer is enhanced in the metal layer, resulting in high spin conversion efficiency.

[0114] RuO ２ A metal layer (including an alloy layer) may be formed adjacent to the layer, for example, a Pt layer, [Pt / Ir] ｎ The metal layer is a Ru / Pt layer, a Ru / Pt layer, and a Ti / Pt layer, so that the Pt layer has a (111) orientation. A recording layer is provided adjacent to the metal layer, and the magnetic layer of the recording layer, for example, a Co layer, has an fcc (111) orientation. The magnetic layer has perpendicular magnetic anisotropy.

[0115] RuO ２ In the case of random orientation of the layers (polycrystalline), RuO ２ It has been confirmed that the layer should be 5 nm or thicker. ２ The layer thickness may be as large as, for example, 50 nm. ２ The spin conversion efficiency θ of a layer with a thickness of 10 nm is higher than that of a layer with a thickness of 5 nm. ＳＨ is large. ２ Even if the layer thickness is made thicker than 25 nm, there is no enhancement effect. Therefore, depending on the manufacturing process, RuO ２ Layer thickness t ＲｕＯ２ is 5 nm ≦ t ＲｕＯ２ It is more preferable to select ≦25 nm.

[0116] <Verification Experiment 14> In verification experiment 14, as shown in FIG. 34, a 10 nm RuO ２ A plurality of samples were fabricated by stacking a W layer, a 0.7 nm CoFeB layer, a 1.5 nm MgO layer, and a 1.5 nm Ta layer in this order. Ｗ The thicknesses were set to 1.5 nm, 2 nm, 2.5 nm, 3 nm, 4 nm, 5 nm, 6 nm, and 7 nm. The substrate used was a Si substrate on which a thermal oxide film was formed.

[0117] FIG. 35 shows the results of X-ray diffraction (XRD) of a plurality of samples prepared in Verification Experiment 14. The thickness t Ｗ The X-ray diffraction (XRD) results for the 2 nm, 4 nm, and 7 nm samples are shown in Figure 1. The horizontal axis represents 2θ, and the vertical axis represents the X-ray diffraction intensity (arbitrary scale). Here, θ is the angle of incidence of the X-ray onto the atomic plane.

[0118] From Fig. 35, a peak of α-W(110) was observed at 2θ of about 40 degrees. ２ The upper W was found to be an α-W (110) oriented film.

[0119] The MH curve (magnetization curve) was measured for each sample prepared in Verification Experiment 14. Ｗ 36B is the MH curve of the sample with the W layer thickness t Ｗ 36C shows the MH curve of the sample with the W layer thickness t Ｗ 36D is the MH curve of the sample with the W layer thickness t Ｗ The graph shows the M-H curve for a sample with a thickness of 4 nm. The horizontal axis is the applied magnetic field H (Oe), and the vertical axis is M / Ms. Ms is the saturation value. "In-plane" refers to the case where the applied magnetic field is an in-plane magnetic field, and "Out-of-plane" refers to the case where the applied magnetic field is perpendicular to the surface (magnetic field perpendicular to the plane).

[0120] From the MH curve, the thickness of the W layer t Ｗ When the thickness is 2 nm or less, RuO ２ The CoFeB film on the W layer is a perpendicular magnetization film, and the thickness of the W layer is t Ｗ When the thickness is 2.5 nm or more, RuO ２ It was found that the CoFeB film on the / W was an in-plane magnetized film.

[0121] 37 is a graph showing the dependence of conductance on the thickness of the W layer in Verification Experiment 14. The horizontal axis represents the thickness t Ｗ and the vertical axis is the conductance G ｘｘ (Ω －１ ) The thickness of the W layer is t Ｗ As increases, the conductance G ｘｘ (Ω －１) increases. Ｗ The resistivity was 34.2 μΩcm. ｘ The resistivity ρ of CoFeB-RuOx was 168 μΩcm. Since W has an α structure, RuO ２ The resistivity of W above is CoFeB, RuO ２ When a current is passed through the device, the majority of the current flows through the W layer.

[0122] FIG. 38A shows the thickness of the W layer t Ｗ FIG. 38B shows the measurement results of the Hall resistance Rxy (Ohm) when an external magnetic field H (mT) is applied to a sample having a W layer thickness t Ｗ This figure shows the measurement results of the Hall resistance Rxy (Ohm) when an external magnetic field H (mT) is applied to a sample with a thickness of 2 nm. The vertical axis represents the Hall resistance Rxy (Ohm), and the horizontal axis represents the external magnetic field H (mT). The anomalous Hall effect curve showed a rectangular anomalous Hall curve depending on the direction of the applied external magnetic field, indicating that the W layer exhibits perpendicular magnetic anisotropy.

[0123] <Verification Experiment 15> In verification experiment 15, as shown in FIG. 39, a 10 nm RuO ２ A plurality of samples were fabricated by stacking a WTa layer, a WTa layer, a 0.7 nm CoFeB layer, a 1.5 nm MgO layer, and a 1.5 nm Ta layer in this order. Ｗ were 1.44 nm, 1.92 nm, 2.4 nm, 2.88 nm, 3.84 nm, 4.8 nm, 5.76 nm, 6.72 nm, and 7.2 nm. The substrate used was a Si substrate on which a thermal oxide film was formed.

[0124] 40 shows the results of X-ray diffraction (XRD) of a number of samples prepared in Verification Experiment 15. The thickness t ＷＴａ The graphs show the X-ray diffraction (XRD) results for the 2.88 nm, 4.8 nm, and 7.2 nm samples. The horizontal axis represents 2θ, and the vertical axis represents the X-ray diffraction intensity (arbitrary scale). Here, θ is the angle of incidence of the X-rays on the atomic plane.

[0125] 40, a peak of α-WTa (110) was observed at 2θ of approximately 40 degrees. ２ The upper WTa was found to be an α-WTa(110) oriented film.

[0126] The MH curve (magnetization curve) was measured for each sample prepared in Verification Experiment 15. ＷＴａ 41B is the MH curve of the sample with the thickness t ＷＴａ 41C shows the MH curve of the sample with the thickness t of the WTa layer set to 1.92 nm. ＷＴａ 41D is the MH curve of the sample with the thickness t ＷＴａ 41E shows the MH curve of the sample with the thickness t of the WTa layer set to 3.84 nm. ＷＴａ 41F shows the MH curve of the sample with the thickness t ＷＴａ This is the M-H curve for a sample with a magnetic field of 7.2 nm. The horizontal axis is the applied magnetic field H (Oe), and the vertical axis is M / Ms. Ms is the saturation value. "In-plane" refers to the case where the applied magnetic field is an in-plane magnetic field, and "Out-of-plane" refers to the case where the magnetic field is perpendicular to the surface (magnetic field perpendicular to the plane).

[0127] From the M-H curve, RuO ２ It was found that the CoFeB film on the WTa film was a perpendicular magnetization film regardless of the thickness of the WTa film.

[0128] 42 is a graph showing the dependence of conductance on the thickness of the WTa layer in Verification Experiment 15. The horizontal axis represents the thickness t ＷＴａ and the vertical axis is the conductance G ｘｘ (Ω －１ ) The thickness of the WTa layer is t ＷＴａ As increases, the conductance G ｘｘ (Ω －１ ) increases. Ｗ The resistivity was 34.9 μΩcm. ｘ The resistivity ρ of CoFeB-RuOx was 168 μΩcm. Since WTa has an α structure, RuO２ The resistivity of WTa above is ２ The resistance of the W layer was found to be about one-fifth that of the W film, making it a suitable electrode material.

[0129] FIG. 43A shows the thickness of the WTa layer in Verification Experiment 15. ＷＴａ FIG. 43B shows the measurement results of the Hall resistance Rxy (Ohm) when an external magnetic field H (mT) is applied to a sample having a thickness t of 1.44 nm in the WTa layer in Verification Experiment 15. ＷＴａ FIG. 43C shows the measurement results of the Hall resistance Rxy (Ohm) when an external magnetic field H (mT) is applied to a sample having a thickness t of 2.4 nm in the WTa layer in Verification Experiment 15. ＷＴａ FIG. 43D shows the measurement results of the Hall resistance Rxy (Ohm) when an external magnetic field H (mT) is applied to a sample having a thickness t of 3.84 nm in Verification Experiment 15. ＷＴａ This figure shows the measurement results of the Hall resistance Rxy (Ohm) when an external magnetic field H (mT) is applied to a sample with a 5.76 nm thickness. The vertical axis represents the Hall resistance Rxy (Ohm), and the horizontal axis represents the external magnetic field H (mT). The anomalous Hall effect curve showed a rectangular anomalous Hall curve depending on the direction of the applied external magnetic field, indicating that the WTa layer exhibits perpendicular magnetic anisotropy.

[0130] FIG. 44 shows the spin conversion efficiency (spin Hall angle) θ ＳＨ RuO ２ / W / CFB / W layer thickness t Ｗ , RuO ２ / WTa / CFB / WTa layer thickness t ＷＴａ The horizontal axis represents the thickness t of the W layer. Ｗ , the thickness of the WTa layer t ＷＴａ , the vertical axis is the spin conversion efficiency θ ＳＨ is.

[0131] The sign of the spin Hall effect is reversed in the Pt and W systems, and the negative spin Hall angle θ ＳＨ was observed. ２ / W system, RuO ２ Absolute value of the spin Hall angle in the WTa system |θＳＨ The magnitude of | is the absolute value of the spin Hall angle |θ ＳＨ Compared with the magnitude of |, it is clear that the absolute value is large in the region where the W and WTa film thicknesses are thin, and the current-spin conversion efficiency is improved.

[0132] RuO ２ / W / CoFeB W layer thickness t Ｗ , RuO ２ / WTa / CoFeB W layer thickness t ＷＴａ When the thickness of the layer is reduced, the absolute value of the spin conversion efficiency (spin Hall angle) |θ ＳＨ | becomes larger, and the thickness of the W layer t Ｗ = 2 nm, the thickness of the WTa layer t ＷＴａ = 2 nm, it becomes the maximum.

[0133] As described above, this is a layer containing Ru and O (for example, RuO ２ This is because the orbital current generated between the W layer and the metal layer is enhanced in the W and WTa layers. ＳＨ is about 7% to 8%, and the magnitude of the spin conversion efficiency of WTa |θ ＳＨ The underlayer is made of RuO. ２ The presence of the W layer provides high spin conversion efficiency. Ｗ 44, that is, in the range of about 2.5 nm or less. This range is limited by the fact that the W layer is a perpendicular magnetization film. ＷＴａ The thickness t of the WTa layer is preferably within the range shown by the curve in FIG. ＷＴａ If the thickness becomes too thick, the θ ＳＨ The value becomes close to , and the enhancement effect is weakened.

[0134] RuO ２ / W W layer thickness t Ｗ is 0<t Ｗ ≦2.4 nm is preferred. Ｗ It is known that even if W is 1 nm thick on Ru oxide, a flat W film can be obtained without island-like growth.

[0135] RuO２ / WTa WTa layer thickness t ＰｔＩｒ is 0<t ＷＴａ ≦7 nm is preferred. ＷＴａ It is known that even if WTa is 1 nm thick on Ru oxide, a flat WTa layer can be obtained without island-like growth.

[0136] <Verification Experiment 16> In verification experiment 16, as shown in FIG. 45, a 10 nm RuO ２ A plurality of samples were fabricated by stacking a 1.92 nm WTa layer, a 0.7 nm CoFeB layer, a 1.5 nm MgO layer, and a 1.5 nm Ta layer in this order. Ｃｒ The thicknesses were set to 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, and 8 nm. The substrate used was a Si substrate on which a thermal oxide film was formed.

[0137] <Verification Experiment 17> In verification experiment 17, as shown in FIG. 46, a 10 nm RuO ２ A plurality of samples were fabricated by stacking a 1.92 nm WTa layer, a V layer, a 0.7 nm CoFeB layer, a 1.5 nm MgO layer, and a 1.5 nm Ta layer in this order. Ｖ The thicknesses were set to 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, and 8 nm. The substrate used was a Si substrate on which a thermal oxide film was formed.

[0138] 47 is a diagram showing the dependence of conductance on the thickness of the Cr layer and the V layer for Verification Experiments 16 and 17. The horizontal axis represents the thickness t Ｃｒ , t Ｖ and the vertical axis is the conductance G ｘｘ (Ω －１ ) The thickness of the Cr layer is t Ｃｒ , the thickness of the V layer t Ｖ As increases, the conductance G ｘｘ (Ω －１ ) increases. Ｃｒ The resistivity ρ of the V layer was 34.9 μΩcm. Ｖ The resistivity of RuO was 45.9 μΩcm. ２Since Cr and V on WTa are metals, it was found that they have low resistivity and are suitable as wiring materials. When a current is passed through the device, a large amount of current flows through the WTa / Cr film and the WTa / W film.

[0139] FIG. 48 shows the spin conversion efficiency (spin Hall angle) θ ＳＨ RuO ２ / WTa / Cr / CFB system Cr layer thickness t Ｃｒ , RuO ２ / WTa / V / CFB system V layer thickness t Ｖ The horizontal axis represents the thickness t of the Cr layer. Ｃｒ , the thickness of the V layer t Ｖ , the vertical axis is the spin conversion efficiency θ ＳＨ is.

[0140] RuO ２ Absolute value of spin Hall angle |θ in the WTa / Cr / CFB system ＳＨ The magnitude of | is the absolute value of the spin Hall angle |θ ＳＨ Compared with the magnitude of |θ ＳＨ It was revealed that the current-spin conversion efficiency was improved.

[0141] RuO ２ Absolute value of the spin Hall angle in the WTa / Cr / CFB system |θ ＳＨ | is t Ｃｒ ≦7 nm, RuO ２ Absolute value of spin Hall angle |θ in the / WTa / V / CFB system ＳＨ | is 0≦t Ｖ The absolute value of the spin Hall angle |θ of α-WTa in the entire V film thickness range of ≦8 nm ＳＨ | was observed to be larger, indicating that the current-spin conversion efficiency was improved.

[0142] Since both Cr and V are metals with low resistivity, it is believed that by inserting a Cr layer or a V layer, the resistance value of the element can be further reduced, thereby reducing power consumption and providing a desirable effect.

[0143] FIG. 49A shows the results of verification experiments 14 and 15. ２ / W / CFB series, RuO ２ 49B shows the dependence of the spin Hall conductivity of the RuO / WTa / CFB system on the thickness of W and WTa. ２ / WTa / Cr / CFB system, RuO ２ 1 shows the dependence of the spin Hall conductivity of the Cr and V film thicknesses in the / WTa / V / CFB system.

[0144] Spin Hall conductivity σ ＳＨ is σ ＳＨ =θ ＳＨ / ρ ｘｘ The resistivity of the entire electrode film is given by ρ ｘｘ Since the power consumption is considered, the value of θ ＳＨ than σ ＳＨ is a closer value.

[0145] In the W system, the spin Hall conductivity σ ＳＨ Since the value of is large, it became clear that within the measured range, the power consumption decreased as the film thickness of W, WTa, Cr, and V increased.

[0146] FIG. 50 shows a typical electron microscope image of the device (Hall bar) created in the aforementioned demonstration experiment and its trace.

[0147] In the embodiment of the present invention, the metal layer 12 is made of RuO ２ Since the metal layer 12 is sandwiched between the Pt—Ir layer and the magnetic layer that constitutes the recording layer, it is necessary for Pt, Pt—Ir, W, and W—Ta to be in contact with the magnetic layer. Therefore, for example, when the metal layer 12 is a Pt—Ir laminated film, RuO ２ When the metal layer 12 is a laminated film of Cr / W—Ta alloy or a laminated film of V / W—Ta alloy, RuO ２ Layer / Cr layer / W-Ta alloy layer / magnetic layer, RuO ２ When the metal layer 12 is a laminated film of Cr / W or a laminated film of V / W, RuO ２ Layer / Cr layer / W layer / magnetic layer, RuO ２The order is layer / V layer / W layer / magnetic layer. The character before the " / " (slash) indicates the lower layer, and the character after the " / " (slash) indicates the upper layer. Note that "upper" and "lower" only indicate a relative order.

[0148] 1: Magnetoresistance effect element 2: Magnetic memory device (integrated circuit) 3: Logic LSI (integrated circuit) 4: Logic section 5: Memory section 10: Substrate 11: Layer containing Ru and O 12: Metal layer 13: Recording layer 14: Barrier layer (tunnel barrier layer) 15: Reference layer 16: Wiring layer 17: Cap layer

Claims

1. A magnetoresistive element comprising: a layer containing Ru and O; a metal layer provided adjacent to the layer containing Ru and O; a recording layer including a magnetic material provided adjacent to the metal layer; a barrier layer; and a reference layer, wherein the metal layer contains one or more metals selected from the group consisting of Pt, W, Ta, Ti, Cr, and V.

2. The magnetoresistive element of claim 1, wherein the metal layer comprises any one of a Pt layer, a Pt alloy layer, a Pt / Ir laminated film, a Ru / Pt laminated film, a Ti / Pt laminated film, a W layer, a W-Ta alloy layer, a Cr / W laminated film, a Cr / W-Ta alloy laminated film, a V / W laminated film, and a V / W-Ta alloy laminated film.

3. The magnetoresistive element according to claim 2, wherein the Pt layer and the magnetic material in any one of the Pt layer, the Pt alloy layer, the Pt / Ir laminated film, the Ru / Pt laminated film and the Ti / Pt laminated film have an fcc(111) orientation.

4. The layer containing Ru and O is RuO ２ 4. The magnetoresistive element according to claim 1, wherein the magnetoresistive element is a layer having a random orientation.

5. The magnetoresistive element according to any one of claims 1 to 4, wherein the magnetization of said recording layer is reversed by passing a current through said metal layer and said layer containing Ru and O.

6. A magnetoresistive effect element according to any one of claims 1 to 5, wherein the recording layer comprises a first magnetic layer adjacent to the metal layer, an insertion layer adjacent to the first magnetic layer, and a second magnetic layer adjacent to the insertion layer.

7. An integrated circuit comprising the magnetoresistive element according to any one of claims 1 to 6.

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