Multilayer film, magnetoresistance effect element, semiconductor memory and logic LSI

Abstract

To provide a laminate film with strong interlayer exchange coupling strength between the top and bottom two magnetic layers, a magnetoresistance effect element, a semiconductor memory, and a logic LSI.SOLUTION: A laminate film 10 has a first magnetic layer 11, an antiferromagnetic coupling layer 12 adjacent to the first magnetic layer, and a second magnetic layer 13 adjacent to the antiferromagnetic coupling layer and antiferromagnetically coupled to the first magnetic layer, and the antiferromagnetic coupling layer 12 includes a layer containing an Ir-Re alloy, where the atomic percentage of Re in the Ir-Re alloy is greater than 0% and equal to or less than 12.5%. A magnetoresistance effect element, a semiconductor memory and a logic LSI have one or more of these laminate films.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a laminated film, a magnetoresistive element, a semiconductor memory, and a logic LSI. [Background technology]

[0002] In a magnetic tunnel junction (MTJ) element, an interlayer anti-ferromagnetic (Synthetic Anti-ferromagnetic) coupling layer is used as a pin layer in which the direction of magnetization is fixed. In MTJ elements, STT-MRAM (Magnetic Random Access Memory) that rewrites data in the recording layer using spin transfer torque (STT) and SOT-MRAM that rewrites data in the recording layer using spin orbit torque (SOT) induced magnetization reversal are known. It has also been proposed to use an interlayer anti-ferromagnetic coupling layer as a conductive layer in a SOT-MRAM element.

[0003] When a perpendicular magnetization material is used for the magnetic material, the size of the element can be made smaller and arranged at a higher density than when an in-plane magnetized magnetic material is used, and the memory capacity can be improved. However, it is known that a small perpendicular magnetic anisotropy leads to poor thermal stability. In addition, Non-Patent Documents 1 and 2 disclose the problem that a small coupling strength between ferromagnetic layers in STT-MRAM increases write errors due to backhopping.

[0004] Patent Document 1 discloses that an Ir layer and a Ru layer are used as an interlayer antiferromagnetic coupling layer. As the element size is reduced, the stability of the Pin layer deteriorates, and writing errors due to backhopping increase, so an interlayer antiferromagnetic coupling layer with stronger exchange coupling strength than an Ir layer and a Ru layer is required. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2022-33026 [Non-patent literature]

[0006] [Non-Patent Document 1] W. Kim et al., IEEE Trans. Magn. 52, 3401004 (2016) [Non-Patent Document 2] T. Devolder et al., Phys. Rev. B 102, 184406 (2020) Summary of the Invention [Problem to be solved by the invention]

[0007] Thus, there is a demand for a laminated film having strong coupling strength between upper and lower magnetic layers having perpendicular magnetic anisotropy.

[0008] SUMMARY OF THE PRESENT EMBODIMENTS The present invention has an object to provide a laminated film having a strong interlayer exchange coupling strength between upper and lower magnetic layers, as well as a magnetoresistive element, a semiconductor memory, and a logic LSI including the same. [Means for solving the problem]

[0009] The present invention has the following concept. [1] A first magnetic layer; an antiferromagnetic coupling layer adjacent to the first magnetic layer; a second magnetic layer adjacent to the antiferromagnetic coupling layer and antiferromagnetically coupled to the first magnetic layer; Equipped with The antiferromagnetic coupling layer includes a layer containing an Ir-Re alloy, and the atomic percentage of Re in the Ir-Re alloy is greater than 0% and is 12.5% ​​or less. [2] The laminated film according to [1] above, wherein the atomic percentage of Re in the Ir-Re alloy is 10% or less. [3] The laminated film according to [1] above, wherein the atomic percentage of Re in the Ir-Re alloy is 4.5% or less. [4] The laminated film according to [1], wherein the layer containing Ir and Re in the antiferromagnetic coupling layer has a thickness greater than 0.2 nm and smaller than 1.0 nm. [5] The laminated film according to [1] above, wherein at least one of the first magnetic layer and the second magnetic layer comprises a laminate of a Co layer and a Pt layer. [6] The laminated film according to [1], wherein the antiferromagnetic coupling layer comprises a layer containing the Ir-Re alloy and a layer containing Pt or an alloy of Pt. [7] The laminated film according to [1], wherein the antiferromagnetic coupling layer comprises a layer containing the Ir--Re alloy and a layer containing Ir. [8] A recording layer, a barrier layer, and a reference layer; the recording layer and the reference layer sandwich the barrier layer, A magnetoresistance effect element, wherein the reference layer comprises the stacked film according to any one of [1] to [7] above. [9] A semiconductor memory device comprising: a conductive layer, a recording layer, a barrier layer, and a reference layer; The conductive layer comprises the laminated film according to any one of [1] to [7] above, A magnetoresistive element in which the direction of magnetization in the recording layer is reversed by a write current flowing through the conductive layer.

[10] A semiconductor memory comprising the magnetoresistive element according to [8].

[11] A logic LSI having the magnetoresistive effect element according to [8].

[12] A semiconductor memory comprising the magnetoresistive effect element according to [9].

[13] A logic LSI having the magnetoresistive effect element according to [9]. Effect of the Invention

[0010] According to the present invention, a laminated film includes a first magnetic layer, an antiferromagnetic coupling layer adjacent to the first magnetic layer, and a second magnetic layer adjacent to the antiferromagnetic coupling layer and antiferromagnetically coupled to the first magnetic layer, the antiferromagnetic coupling layer includes a layer containing an Ir-Re alloy, and the atomic percentage of Re in the Ir-Re alloy is greater than 0% and less than or equal to 12.5%, so that the interlayer exchange coupling strength between the first magnetic layer and the second magnetic layer is strong. By using such a laminated film in a magnetoresistance effect element, in a semiconductor memory including STT-MRAM, SOT-MRAM, and MRAM, in a conductive layer for SOT-MRAM, or in a logic LSI, a spin device having good thermal stability and good heat resistance that can be pinned strongly while maintaining perpendicular magnetic anisotropy even after an annealing process during fabrication can be provided. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic cross-sectional view of a laminated film according to a first embodiment of the present invention. [Figure 2A] FIG. 2A is a schematic cross-sectional view of a laminated film according to a second embodiment of the present invention. [Figure 2B] FIG. 2B is a schematic cross-sectional view of a laminated film according to a third embodiment of the present invention. [Figure 3A] FIG. 3A is a schematic cross-sectional view of a laminated film according to a fourth embodiment of the present invention. [Figure 3B] FIG. 3B is a schematic cross-sectional view of a laminated film according to a fifth embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view showing an outline of a magnetoresistance effect element according to a sixth embodiment of the present invention. [Diagram 5] FIG. 5 is a cross-sectional view showing in detail a magnetoresistive effect element according to a sixth embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view showing an outline of a magnetoresistive effect element according to a seventh embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view showing an outline of an SOT-MRAM according to an eighth embodiment of the present invention. [Figure 8] FIG. 8 is a cross-sectional view showing an outline of an SOT-MRAM according to a ninth embodiment of the present invention. [Figure 9] FIG. 9 is a cross-sectional view showing an outline of an SOT-MRAM according to a tenth embodiment of the present invention. [Figure 10A] FIG. 10A is a diagram showing the structure of a sample in verification experiment 1. [Figure 10B] FIG. 10B is a diagram showing the structure of the sample in verification experiment 2. [Figure 10C] FIG. 10C is a diagram showing the structure of a sample in verification experiment 3. [Figure 11A] FIG. 11A is a graph showing an MH curve of a sample in which the Ir film thickness tIr is set to 0.5 nm in verification experiment 1. [Figure 11B] FIG. 11B shows the MH curve of a sample of Ir97.5Re2.5 with a film thickness tIrRe of 0.4 nm. [Figure 12] FIG. 12 is a diagram showing the film thickness dependence of the interlayer interaction of Ir or IrRe for Verification Experiments 1 and 2. In FIG. [Figure 13A] FIG. 13A is a diagram showing an MH curve of a sample in Verification Experiment 1, which has an interlayer bonding layer with a thickness of 0.8 nm. [Figure 13B] FIG. 13B is a diagram showing an MH curve of a sample in Verification Experiment 2, which has an interlayer bonding layer with a thickness of 0.8 nm. [Figure 13C] FIG. 13C is a diagram showing an MH curve of a sample in Verification Experiment 3, which has an interlayer bonding layer with a thickness of 0.8 nm. [Figure 14A] FIG. 14A is a graph showing an MH curve of a sample in Verification Experiment 1, the sample having an interlayer bonding layer with a thickness of 1.4 nm. [Figure 14B] FIG. 14B is a graph showing an MH curve of a sample in Verification Experiment 2, the sample having an interlayer bonding layer with a thickness of 1.4 nm. [Figure 14C] FIG. 14C is a graph showing an MH curve of the sample in Verification Experiment 3, which has an interlayer bonding layer having a thickness of 1.4 nm. [Figure 15]FIG. 15 is a diagram showing the structure of the sample in verification experiment 4. [Figure 16A] FIG. 16A shows the results of MH measurements of a sample having an interlayer coupling layer of Ir and a thickness of 0.5 nm that provides antiferromagnetic coupling after annealing at 300° C. for 1 hour in vacuum. [Figure 16B] FIG. 16B shows the results of MH measurements of a sample having an interlayer coupling layer of Ir95.5Re4.5 and a thickness of 0.45 nm that provides antiferromagnetic coupling, after annealing at 300° C. for 1 hour in vacuum. [Figure 16C] FIG. 16C shows the results of MH measurements of a sample having an interlayer coupling layer of Ir91.5Re8.5 and a thickness of 0.5 nm that provides antiferromagnetic coupling after annealing at 300° C. for 1 hour in vacuum. [Figure 17A] FIG. 17A shows the results of MH measurements of a sample having an interlayer coupling layer of Ir and a thickness of 0.45 nm for antiferromagnetic coupling, after annealing at 400° C. for 1 hour in vacuum. [Figure 17B] FIG. 17B shows the results of MH measurements of a sample having an interlayer coupling layer of Ir95.5Re4.5 and an antiferromagnetic coupling thickness of 0.45 nm, after annealing at 400° C. for 1 hour in vacuum. [Figure 17C] FIG. 17C shows the results of MH measurements of a sample having an interlayer coupling layer of Ir91.5Re8.5 and a thickness of 0.5 nm that provides antiferromagnetic coupling, after annealing at 400° C. for 1 hour in vacuum. [Figure 18A] FIG. 18A is a graph showing the dependence of the interlayer bonding strength |Jex| (mJ / m2) of the IrRe film thickness tIrRe on the IrRe film thickness tIrRe for the sample annealed in vacuum at 300° C. for 1 hour in verification experiment 4. [Figure 18B] FIG. 18B is a graph showing the dependence of the interlayer bonding strength |Jex| (mJ / m2) of the IrRe film thickness tIrRe on the IrRe film thickness tIrRe for the sample annealed in vacuum at 400° C. for 1 hour in verification experiment 4. [Figure 19A] FIG. 19A shows the results of MH measurement of a sample having an interlayer bonding layer Ir97.5Re2.5 with a thickness tIrRe0.4 nm after annealing at 300° C. [Figure 19B]FIG. 19B shows the results of MH measurement of a sample having an interlayer bonding layer Ir97.5Re2.5 with a thickness tIrRe0.4 nm after annealing at 400° C. [Figure 20A] FIG. 20A shows the results of MH measurement of a sample having an interlayer coupling layer Ir98.5Re1.5 with a thickness tIrRe0.35 nm after annealing at 300° C. [Figure 20B] FIG. 20B shows the results of MH measurement of a sample having an interlayer coupling layer Ir98.5Re1.5 with a thickness tIrRe0.35 nm after annealing at 400° C. [Figure 21] FIG. 21 is a diagram showing the dependency of interlayer bonding strength on the Re composition. [Figure 22A] FIG. 22A is a diagram showing the structure of a sample in verification experiment 5. [Figure 22B] FIG. 22B is a diagram showing the structure of the sample in verification experiment 6. [Figure 22C] FIG. 22C is a diagram showing the structure of a sample in verification experiment 7. [Figure 23A] FIG. 23A shows the MH curve of a sample having a Pt layer with a thickness tPt of 0.4 nm and an interlayer bonding layer of Ir95.5Re4.5. [Figure 23B] FIG. 23B shows the MH curves of two samples with an interlayer bonding layer of Ir95.5Re4.5. [Figure 24A] FIG. 24A shows the MH curve of a sample having a Pt layer with a thickness tPt of 0.6 nm and an interlayer bonding layer Ir97.5Re2.5 layer. [Figure 24B] FIG. 24B shows the MH curves of three samples with an interlayer bonding layer of Ir97.5Re2.5. [Figure 25A] FIG. 25A shows the MH curve of a sample having a Pt layer with a thickness tPt of 0.6 nm and an Ir98.5Re1.5 interlayer bonding layer. [Figure 25B] FIG. 25B shows the MH curves of the three samples having an interlayer bonding layer of Ir98.5Re1.5. [Figure 26] FIG. 26 shows the Ru thickness dependence of the interlayer bonding strength |Jex| as comparative experiment 1. [Figure 27]FIG. 27 shows the Ir thickness dependence of the interlayer bonding strength |Jex| as comparative experiment 2. [Figure 28A] FIG. 28A is a diagram showing the structure of a sample in verification experiment 8. [Figure 28B] FIG. 28B is a diagram showing the structure of the sample in verification experiment 9. [Figure 28C] FIG. 28C is a diagram showing the structure of the sample in Comparative Experiment 3. [Figure 29] Figure 29A is the MH curve of a sample in which the thickness tIrRe of the Re / Ir / Re stack was 0.5 nm in verification experiment 8, Figure 29B is the MH curve of a sample in which the thickness tIrRe of the Ir / Re / Ir stack was 0.5 nm in verification experiment 9, and Figure 29C is the MH curve of a sample in which the Ir thickness tIr was 0.55 nm in comparison experiment 3. [Diagram 30] FIG. 30 plots the interlayer bonding strength |Jex| as a function of the film thickness tIrRe of the samples in verification experiments 8 and 9 and the film thickness tIr of sample 3 in comparison experiment 3. [Diagram 31] FIG. 31 is a diagram showing a semiconductor memory as an integrated circuit according to an eleventh embodiment of the present invention. [Diagram 32] FIG. 32 is a diagram showing a schematic diagram of a logic LSI as an integrated circuit according to the twelfth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] 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.

[0013] <First embodiment> FIG. 1 is a schematic diagram showing a cross section of a laminated film according to a first embodiment of the present invention. A laminated film 10 according to the first embodiment of the present invention includes a first magnetic layer 11, an antiferromagnetic coupling layer 12 adjacent to the first magnetic layer 11, and a second magnetic layer 13 adjacent to the antiferromagnetic coupling layer 12, and the second magnetic layer 13 is antiferromagnetically coupled to the first magnetic layer 11. That is, the laminated film 10 is configured by laminating the first magnetic layer 11, the antiferromagnetic coupling layer 12, and the second magnetic layer 13 in this order. The antiferromagnetic coupling layer 12 includes a layer (referred to as an "interlayer coupling layer") 12a made of an Ir-Re alloy. In the first embodiment of the present invention, the antiferromagnetic coupling layer 12 is configured by an interlayer coupling layer 12a, and the interlayer coupling layer 12a has a first surface and a second surface, and the first surface is located on the upper and lower opposite sides to the second surface. A first surface (the lower surface in FIG. 1) of the interlayer coupling layer 12a contacts the first magnetic layer 11, and a second surface (the upper surface in FIG. 1) of the interlayer coupling layer 12a contacts the second magnetic layer 13.

[0014] The first magnetic layer 11 and the second magnetic layer 13 are ferromagnetic layers whose magnetization direction is perpendicular to the film surface. The first magnetic layer 11 and the second magnetic layer 13 include a layer made of a ferromagnetic material containing one or more ferromagnetic transition metal elements. The ferromagnetic material includes at least one of Co, Fe, Ni, etc. The first magnetic layer 11 and the second magnetic layer 13 may include a layer made of a nonmagnetic element in addition to the layer made of a ferromagnetic material, and the nonmagnetic element includes W, Ta, Hf, Zr, Nb, Mo, Ti, V, Cr, Si, Al, B, Pd, and Pt. The first magnetic layer 11 may have the same configuration as the second magnetic layer 13, or may have a different configuration.

[0015] The first magnetic layer 11 and the second magnetic layer 13 are antiferromagnetically coupled via an interlayer coupling layer 12a. As the thickness of the non-magnetic layer (also referred to as the "interlayer coupling non-magnetic layer") that constitutes the interlayer coupling layer 12a increases, the exchange coupling strength between the first magnetic layer 11 and the second magnetic layer 13 becomes stronger or weaker. The strength (peak value) at which the exchange coupling strength becomes stronger as the thickness of the interlayer coupling layer 12a increases also gradually decreases. As the thickness of the interlayer coupling layer 12a is increased from a smaller value, the thickness at which the exchange coupling strength reaches the first peak becomes a value shorter than about 0.5 nm (see FIGS. 18A and 18B).

[0016] In the interlayer coupling layer 12a, the Re atomic ratio in the Ir-Re alloy is greater than 0% and about 12.5% or less. That is, when the Ir-Re alloy is represented by the chemical formula of Ir x Re y , x and y satisfy x + y = 100 and 0 < y ≤ 12.5.

[0017] It is preferable that the atomic ratio of Re in the Ir-Re alloy is 10% or less. That is, it is preferable that y satisfies 0 < y ≤ 10. This is because the interlayer exchange coupling strength becomes about 1 mJ / m 2 or more.

[0018] More preferably, the atomic ratio of Re in the Ir-Re alloy is 4.5% or less. That is, it is more preferable that y satisfies 0 < y ≤ 4.5. This is because the interlayer exchange coupling strength becomes a value higher than about 2 mJ / m 2 or more.

[0019] Even more preferably, the atomic ratio of Re in the Ir-Re alloy is 2.5% or less. That is, it is preferable that y satisfies 0 < y ≤ 2.5. This is because the interlayer exchange coupling strength becomes about 2.5 mJ / m 2 or more.

[0020] By including Re in the Ir-Re alloy in the interlayer coupling layer 12a, for example by including 0.1% or more of Re, more preferably 0.2% or more, and even more preferably 0.5% or more of Re, the interlayer coupling strength is increased compared to when no Re is included. Since the interlayer exchange coupling strength is maximized in the thin region of the interlayer coupling layer 12a, the interaction between the first magnetic layer 11 and the second magnetic layer 13 is increased (see, for example, FIGS. 18A and 18B).

[0021] The layer containing the Ir-Re alloy (interlayer coupling layer 12a) has a thickness greater than 0.2 nm, and more preferably greater than 0.3 nm. The layer containing the Ir-Re alloy (interlayer coupling layer 12a) has a thickness less than 1.0 nm, and more preferably 0.6 nm or less. In the first embodiment, the layer containing Ir and Re in the antiferromagnetic coupling layer 12 is composed of the interlayer coupling layer 12a.

[0022] In the first embodiment of the present invention, the antiferromagnetic coupling layer 12 includes a layer (interlayer coupling layer 12a) made of an alloy of Ir and Re, thereby enhancing exchange coupling between the first magnetic layer 11 and the second magnetic layer 13, increasing perpendicular magnetic anisotropy, and providing good thermal stability. The laminated film 10 also has heat resistance of 300°C to 400°C.

[0023] <Second embodiment> 2A is a schematic diagram showing a cross section of a laminated film according to a second embodiment of the present invention. A laminated film 10A according to the second embodiment of the present invention includes a first magnetic layer 11, an antiferromagnetic coupling layer 12 adjacent to the first magnetic layer 11, and a second magnetic layer 13 adjacent to the antiferromagnetic coupling layer 12, and the second magnetic layer 13 is antiferromagnetically coupled to the first magnetic layer 11. That is, the laminated film 10A is configured by laminating the first magnetic layer 11, the antiferromagnetic coupling layer 12, and the second magnetic layer 13 in this order.

[0024] In the second embodiment of the present invention, the antiferromagnetic coupling layer 12 is composed of a layer (interlayer coupling layer) 12a made of an Ir-Re alloy and a nonmagnetic layer 12b. The composition of the Ir-Re alloy in the layer 12a made of an Ir-Re alloy is the same as in the first embodiment of the present invention. The nonmagnetic layer 12b is made of a metal or alloy containing Pt. An example of an alloy containing Pt is Pt-Pd. The first magnetic layer 11 is the same as the first magnetic layer 11 in the first embodiment of the present invention, and the second magnetic layer 13 is the same as the second magnetic layer 13 in the first embodiment of the present invention.

[0025] In the second embodiment of the present invention, the antiferromagnetic coupling layer 12 is composed of an interlayer coupling layer 12a and a nonmagnetic layer 12b, and the interlayer coupling layer 12a has a first surface and a second surface, and the first surface is located on the opposite side to the second surface. The interlayer coupling layer 12a contacts the first magnetic layer 11 at the first surface (the lower surface in the embodiment shown in FIG. 2A), and the interlayer coupling layer 12a contacts the nonmagnetic layer 12b at the second surface (the upper surface in the embodiment shown in FIG. 2A). The antiferromagnetic coupling layer 12 includes one interlayer coupling layer 12a and one nonmagnetic layer 12b. Here, the antiferromagnetic coupling layer 12 is different in the top and bottom from the embodiment shown in FIG. 2A, and the interlayer coupling layer 12a may contact the second magnetic layer 13, and the nonmagnetic layer 12b may contact the first magnetic layer 11. That is, the first surface (lower surface) of the interlayer coupling layer 12a may be in contact with the nonmagnetic layer 12b, and the second surface (upper surface) of the interlayer coupling layer 12a may be in contact with the second magnetic layer 13. The thickness of the interlayer coupling layer 12a is the same as in the first embodiment.

[0026] In the second embodiment of the present invention, since the antiferromagnetic coupling layer 12 includes the interlayer coupling layer 12a and the nonmagnetic layer 12b, when the nonmagnetic layer 12b is made of a material having a large spin Hall effect, such as Pt or Pt-Pd, the spin torque is larger than when the nonmagnetic layer 12b is not provided, and the magnetization of the first magnetic layer 11 and the second magnetic layer 13 is efficiently reversed. The laminated film 10A according to the second embodiment of the present invention can also be used as a conductive layer of SOT-MRAM (wiring for SOT-MRAM).

[0027] In the second embodiment of the present invention, the antiferromagnetic coupling layer 12 includes a layer (interlayer coupling layer 12a) made of an alloy of Ir and Re, so that the perpendicular magnetic anisotropy is increased and the thermal stability is good. In addition, the laminated film 10A has a heat resistance of 300°C to 400°C.

[0028] <Third embodiment> 2B is a schematic diagram showing a cross section of a laminated film according to a third embodiment of the present invention. A laminated film 10B according to the third embodiment of the present invention includes a first magnetic layer 11, an antiferromagnetic coupling layer 12 adjacent to the first magnetic layer 11, and a second magnetic layer 13 adjacent to the antiferromagnetic coupling layer 12, and the second magnetic layer 13 is antiferromagnetically coupled to the first magnetic layer 11. That is, the laminated film 10B is configured by laminating the first magnetic layer 11, the antiferromagnetic coupling layer 12, and the second magnetic layer 13 in this order.

[0029] In the third embodiment of the present invention, the antiferromagnetic coupling layer 12 is composed of a layer (interlayer coupling layer) 12a made of an Ir-Re alloy, a first nonmagnetic layer 12b, and a second nonmagnetic layer 12c. The first nonmagnetic layer 12b and the second nonmagnetic layer 12c sandwich the interlayer coupling layer 12a. The composition of the Ir-Re alloy in the interlayer coupling layer 12a is the same as that in the first embodiment of the present invention. The first nonmagnetic layer 12b is made of a metal or alloy containing Pt. The second nonmagnetic layer 12c is made of a metal or alloy containing Pt. An example of an alloy containing Pt is Pt-Pd. The first nonmagnetic layer 12b may have the same composition as the second nonmagnetic layer 12c, or may have a different composition. The first magnetic layer 11 is the same as the first magnetic layer 11 in the first embodiment of the present invention, and the second magnetic layer 13 is the same as the second magnetic layer 13 in the first embodiment of the present invention. The thickness of the interlayer bonding layer 12a is the same as in the first embodiment.

[0030] In the third embodiment of the present invention, since the antiferromagnetic coupling layer 12 includes the first nonmagnetic layer 12b and the second nonmagnetic layer 12c, the spin torque is larger than when the first nonmagnetic layer 12b and the second nonmagnetic layer 12c are not present, and the magnetizations of the first magnetic layer 11 and the second magnetic layer 13 are efficiently reversed. The stacked film 10B according to the third embodiment can also be used as a conductive layer for SOT-MRAM (wiring for SOT-MRAM).

[0031] In the third embodiment of the present invention, the antiferromagnetic coupling layer 12 includes a layer (interlayer coupling layer 12a) made of an alloy of Ir and Re, so that the perpendicular magnetic anisotropy is increased and the thermal stability is good. In addition, the laminated film 10B has a heat resistance of 300°C to 400°C.

[0032] <Fourth embodiment> 3A is a schematic diagram showing a cross section of a laminated film according to a fourth embodiment of the present invention. A laminated film 10C according to the fourth embodiment of the present invention includes a first magnetic layer 11, an antiferromagnetic coupling layer 12 adjacent to the first magnetic layer 11, and a second magnetic layer 13 adjacent to the antiferromagnetic coupling layer 12, and the second magnetic layer 13 is antiferromagnetically coupled to the first magnetic layer 11. That is, the laminated film 10C is configured by laminating the first magnetic layer 11, the antiferromagnetic coupling layer 12, and the second magnetic layer 13 in this order.

[0033] In the fourth embodiment of the present invention, the antiferromagnetic coupling layer 12 is composed of a layer (interlayer coupling layer) 12a made of an Ir-Re alloy and a nonmagnetic layer 12d. The nonmagnetic layer 12d is a layer that does not contain Re and contains Ir (Ir layer). The thickness of the nonmagnetic layer (Ir layer) 12d and the composition of Re in the layer 12a containing an Ir-Re alloy are adjusted so that the composition of Ir and Re when the layer 12a containing an Ir-Re alloy and the nonmagnetic layer 12d are considered as one coincide with the preferred composition in the first embodiment of the present invention. Here, the thickness of the nonmagnetic layer (Ir layer) 12d is determined, which means that the thickness of the layer 12a containing an Ir-Re alloy is adjusted. The first magnetic layer 11 is the same as the first magnetic layer 11 in the first embodiment of the present invention, and the second magnetic layer 13 is the same as the second magnetic layer 13 in the first embodiment of the present invention. In the fourth embodiment, the layer containing Ir and Re in the antiferromagnetic coupling layer 12 is composed of a layer 12a containing an Ir--Re alloy and a nonmagnetic layer 12d.

[0034] In the fourth embodiment of the present invention, the antiferromagnetic coupling layer 12 is composed of an interlayer coupling layer 12a and a nonmagnetic layer 12d, and the interlayer coupling layer 12a has a first surface and a second surface, and the first surface is located on the opposite side to the second surface. The interlayer coupling layer 12a contacts the first magnetic layer 11 at the first surface (the lower surface in the embodiment shown in FIG. 3A), and the interlayer coupling layer 12a contacts the nonmagnetic layer 12d at the second surface (the upper surface in the embodiment shown in FIG. 3A). The antiferromagnetic coupling layer 12 includes one interlayer coupling layer 12a and one nonmagnetic layer 12d. Here, the antiferromagnetic coupling layer 12 is different in the top and bottom from the embodiment shown in FIG. 3A, and the interlayer coupling layer 12a may contact the second magnetic layer 13, and the nonmagnetic layer 12d may contact the first magnetic layer 11. That is, the interlayer coupling layer 12a may be in contact with the nonmagnetic layer 12d on the first surface (lower surface), and the interlayer coupling layer 12a may be in contact with the second magnetic layer 13 on the second surface (upper surface).

[0035] In the fourth embodiment of the present invention, the antiferromagnetic coupling layer 12 includes an interlayer coupling layer 12a and a nonmagnetic layer 12d. The thickness of the interlayer coupling layer 12a is the same as that of the first embodiment. The antiferromagnetic coupling layer 12 is composed of a layer (interlayer coupling layer) 12a made of an Ir-Re alloy and a nonmagnetic layer (Ir layer) 12d. The thickness of the layer (Ir layer) 12d containing Ir and the composition of Re in the layer 12a containing an Ir-Re alloy are adjusted so that the composition of Ir and Re when the layer 12a containing an Ir-Re alloy and the nonmagnetic layer (Ir layer) 12d are considered as one coincides with the preferred composition in the first embodiment of the present invention. The thickness of the antiferromagnetic coupling layer 12 in the fourth embodiment (i.e., the sum of the thickness of the interlayer coupling layer 12a and the thickness of the nonmagnetic layer 12d) is the same as the thickness of the interlayer coupling layer 12a in the antiferromagnetic coupling layer 12 in the first embodiment. In the fourth embodiment, the layer containing Ir and Re in the antiferromagnetic coupling layer 12 is composed of a layer 12a containing an Ir-Re alloy and a nonmagnetic layer 12d. When these conditions are satisfied, the perpendicular magnetic anisotropy is increased and the thermal stability is good, as in the first embodiment. In addition, the laminated film 10C has a heat resistance of 300°C to 400°C. Such a laminated film 10C can be used as a reference layer of an MTJ.

[0036] <Fifth embodiment> 3B is a schematic diagram showing a cross section of a laminated film according to a fifth embodiment of the present invention. A laminated film 10D according to the fifth embodiment of the present invention includes a first magnetic layer 11, an antiferromagnetic coupling layer 12 adjacent to the first magnetic layer 11, and a second magnetic layer 13 adjacent to the antiferromagnetic coupling layer 12, and the second magnetic layer 13 is antiferromagnetically coupled to the first magnetic layer 11. That is, the laminated film 10D is configured by laminating the first magnetic layer 11, the antiferromagnetic coupling layer 12, and the second magnetic layer 13 in this order.

[0037] In the fifth embodiment of the present invention, the antiferromagnetic coupling layer 12 is composed of a layer (interlayer coupling layer) 12a made of an Ir-Re alloy, a first nonmagnetic layer 12d, and a second nonmagnetic layer 12e. The thickness of the interlayer coupling layer 12a is the same as that of the first embodiment. The first nonmagnetic layer 12d and the second nonmagnetic layer 12e sandwich the interlayer coupling layer 12a. The first nonmagnetic layer 12d and the second nonmagnetic layer 12e are layers that do not contain Re and contain Ir (Ir layers). Here, the thicknesses of the first nonmagnetic layer 12d and the second nonmagnetic layer 12e and the composition of Re in the layer 12a containing an Ir-Re alloy are adjusted so that the composition of Ir and Re when the layer 12a containing an Ir-Re alloy, the first nonmagnetic layer 12d, and the second nonmagnetic layer 12e are considered as one unit coincides with the preferred composition in the first embodiment of the present invention. The first nonmagnetic layer 12d may have the same structure as the second nonmagnetic layer 12e, or may have a different structure. The first magnetic layer 11 is the same as the first magnetic layer 11 in the first embodiment of the present invention, and the second magnetic layer 13 is the same as the second magnetic layer 13 in the first embodiment of the present invention. In the fifth embodiment, the layer containing Ir and Re in the antiferromagnetic coupling layer 12 is composed of the first nonmagnetic layer 12d, the layer 12a containing an Ir-Re alloy, and the second nonmagnetic layer 12e.

[0038] In the fifth embodiment of the present invention, the antiferromagnetic coupling layer 12 includes an interlayer coupling layer 12a, a first nonmagnetic layer 12d, and a second nonmagnetic layer 12e. The thicknesses of the first nonmagnetic layer 12d and the second nonmagnetic layer 12e and the Re composition in the layer 12a containing an Ir-Re alloy are adjusted so that the Ir and Re compositions of the layer 12a containing an Ir-Re alloy, the first nonmagnetic layer 12d, and the second nonmagnetic layer 12e as a whole coincide with the preferred compositions in the first embodiment of the present invention. The thickness of the antiferromagnetic coupling layer 12 in the fifth embodiment (i.e., the sum of the thickness of the interlayer coupling layer 12a, the thickness of the first nonmagnetic layer 12d, and the thickness of the second nonmagnetic layer 12e) is the same as the thickness of the interlayer coupling layer 12a in the antiferromagnetic coupling layer 12 in the first embodiment. In the fifth embodiment, the layer containing Ir and Re in the antiferromagnetic coupling layer 12 is composed of a first nonmagnetic layer 12d, a layer 12a containing an Ir-Re alloy, and a second nonmagnetic layer 12e. When these conditions are satisfied, the perpendicular magnetic anisotropy is increased and the thermal stability is good, as in the first embodiment. In addition, the laminated film 10D has a heat resistance of 300°C to 400°C. Such a laminated film 10D can be used as a reference layer of an MTJ. The thickness of the first nonmagnetic layer 12d may be equal to or different from the thickness of the second nonmagnetic layer 12e.

[0039] Sixth embodiment FIG. 4 is a cross-sectional view showing an outline of a magnetoresistance effect element according to a sixth embodiment of the present invention. In the magnetoresistance effect element 20 according to the sixth embodiment of the present invention, the laminated film 10 shown in FIG. 1 is applied as a part of the reference layer 22. That is, the reference layer 22 has a ferromagnetic pinned layer (synthetic antiferromagnetic layer: SAF layer). The magnetoresistance effect element 20 shown in FIG. 4 has a bottom pin structure. That is, the magnetoresistance effect element 20 includes the reference layer 22, the tunnel barrier layer 23, and the recording layer 24 in this order from the bottom, and the laminate of the reference layer 22, the tunnel barrier layer 23, and the recording layer 24 is provided between the seed layer 21 and the cap layer 25.

[0040] The reference layer 22 includes any one of the laminated films 10 described above (for example, the laminated film 10 shown in FIG. 1, the laminated film 10C shown in FIG. 3A, and the laminated film 10D shown in FIG. 3B), and is configured by laminating at least the first magnetic layer 11, the antiferromagnetic coupling layer 12, and the second magnetic layer 13 in this order. The first magnetic layer 11 and the second magnetic layer 13 are antiferromagnetically coupled. The tunnel barrier layer 23 is provided above the second magnetic layer 13 and below the recording layer 24. That is, the tunnel barrier layer 23 is provided between the second magnetic layer 13 and the recording layer 24. The recording layer 24 includes a magnetic layer having perpendicular magnetic anisotropy. A lower electrode 26 is connected to the seed layer 21, the lower electrode 26 is connected to the selection transistor Tr, and an upper electrode 27 is connected to the cap layer 25. The upper electrode 27 is connected to a bit line.

[0041] Such a magnetoresistance effect element 20 constitutes an STT-MRAM. When the selection transistor Tr is in an ON state, a current is passed between the seed layer 21 and the cap layer 25 to rewrite or read the recording layer 24. In this case, in the sixth embodiment of the present invention, since the reference layer 22 includes the stacked films 10, 10C, and 10D, the perpendicular magnetic anisotropy of the first magnetic layer 11 and the second magnetic layer 13 is increased and the thermal stability is good. As a result, the perpendicular magnetization of the first magnetic layer 11 and the second magnetic layer 13 can be more fixed and pinned.

[0042] In the sixth embodiment of the present invention, the reference layer 22 is configured by laminating the first magnetic layer 11, the antiferromagnetic coupling layer 12, and the second magnetic layer 13 in this order, and the first magnetic layer 11 and the second magnetic layer 13 are antiferromagnetically coupled. In this way, the reference layer 22 has a ferromagnetic pinned layer (SAF layer), and the first magnetic layer 11 and the second magnetic layer 13 have high perpendicular magnetic anisotropy, so that the thermal stability is good and writing errors are suppressed even when the element size is miniaturized.

[0043] FIG. 5 is a cross-sectional view showing in detail the magnetoresistance effect element according to the sixth embodiment of the present invention. In the magnetoresistance effect element 20 according to the sixth embodiment of the present invention, the first magnetic layer 11 in the reference layer 22 includes a stack of a Co layer 11a and a Pt layer 11b. The second magnetic layer 13 in the reference layer 22 includes a stack of a Co layer 13a and a Pt layer 13b. The first magnetic layer 11 and the second magnetic layer 13 include a Co / Pt multilayer. The upper and lower layers included in the Co / Pt multilayer in the first magnetic layer 11 are both Co layers 11a. The uppermost Co layer 11a is connected to the antiferromagnetic coupling layer 12 (interlayer coupling layer 12a). The second magnetic layer 13 includes a layer 13c including at least one of Ta, W, Wo, etc., and a CoFeB layer 13d in addition to the Co / Pt multilayer. Both the upper and lower layers included in the Co / Pt multilayer in the second magnetic layer 13 are Co layers 13a. The lowest Co layer 13a is connected to the antiferromagnetic coupling layer 12 (interlayer coupling layer 12a). The uppermost Co layer 13a is connected to a layer 13c including at least one of Ta, W, Wo, etc., and the layer 13c is connected to a CoFeB layer 13d, which is joined to the tunnel barrier layer 23.

[0044] The recording layer 24 includes a CoFeB layer 24a and a layer 24b including at least one of Ta, W, Wo, MgO, etc., and has a stack structure including the CoFeB layer 24a / the layer 24b including at least one of Ta, W, Wo, MgO, etc. / the CoFeB layer 24c. Here, the CoFeB layer 24a / the layer 24b including at least one of Ta, W, Wo, MgO, etc. may be further stacked in multiple layers. Here, the CoFeB layer 13d and the CoFeB layer 24a are provided to increase the magnetoresistance effect (MR). When the tunnel barrier layer 23 is an MgO layer, the CoFeB layer 13d and the CoFeB layer 24a above and below it are preferably iron-rich. When the tunnel barrier layer 23 is an MgO layer, the CoFeB layer 13d is likely to have perpendicular magnetization. The layer 13c is provided to make the crystal structure of the Co / Pt multilayer fcc structure different from the bcc structure of the CoFeB layer 13d and the CoFeB layer 24a near the MgO layer. The layer 13c is provided on the Co / Pt multilayer, and an amorphous layer of CoFeB is formed thereon, MgO crystals are provided, an amorphous layer of CoFeB is provided, and annealed to form the bcc structure of the CoFeB layer 13d and the CoFeB layer 24a near the MgO layer. The cap layer 25 is composed of the MgO layer 25a and a layer 25b containing at least one of Ru, Ta, W, etc. Here, the cap layer 25 may be only the layer 25b containing at least one of Ru, Ta, W, etc.

[0045] In the magnetoresistance effect element 20 shown in FIG. 5, the first magnetic layer 11 and the second magnetic layer 13 in the reference layer 22 have a Co / Pt multilayer, and therefore have strong perpendicular magnetic anisotropy.

[0046] Seventh embodiment FIG. 6 is a cross-sectional view showing an outline of a magnetoresistance effect element according to a seventh embodiment of the present invention. In the magnetoresistance effect element 30 according to the seventh embodiment of the present invention, any one of the above-mentioned various laminated films 10 (for example, the laminated film 10 shown in FIG. 1, the laminated film 10C shown in FIG. 3A, and the laminated film 10D shown in FIG. 3B) is applied as a part (pinned layer) of the reference layer 34. That is, the reference layer 34 has a ferromagnetic pinned layer (SAF layer). The magnetoresistance effect element 30 shown in FIG. 6 has a top pin structure. That is, the magnetoresistance effect element 30 includes a recording layer 32, a tunnel barrier layer 33, and a reference layer 34 in this order from the bottom, and the recording layer 32, the tunnel barrier layer 33, and the reference layer 34 are provided between the seed layer 31 and the cap layer 35.

[0047] The reference layer 34 includes the laminated film 10 shown in FIG. 1, and is configured by laminating at least a first magnetic layer 11, an antiferromagnetic coupling layer 12, and a second magnetic layer 13 in this order. The tunnel barrier layer 33 is provided above the recording layer 32 and below the first magnetic layer 11. The tunnel barrier layer 33 is provided between the recording layer 32 and the first magnetic layer 11. The recording layer 32 includes a magnetic layer having perpendicular magnetic anisotropy. A lower electrode 36 is connected to the seed layer 31, and the lower electrode 36 is connected to the selection transistor Tr, and an upper electrode 37 is connected to the cap layer 35. The upper electrode 37 is connected to a bit line.

[0048] Such a magnetoresistance effect element 30 constitutes an STT-MRAM. When the selection transistor Tr is ON, a current is passed between the seed layer 31 and the cap layer 35 to rewrite or read the recording layer 32. In this case, in the seventh embodiment of the present invention, since the reference layer 34 includes the stacked films 10, 10C, and 10D, the perpendicular magnetic anisotropy of the first magnetic layer 11 and the second magnetic layer 13 is increased and the thermal stability is good. As a result, the perpendicular magnetization of the first magnetic layer 11 and the second magnetic layer 13 can be more fixed and pinned.

[0049] In the seventh embodiment of the present invention, the reference layer 34 is configured by laminating the first magnetic layer 11, the antiferromagnetic coupling layer 12, and the second magnetic layer 13 in this order, and the first magnetic layer 11 and the second magnetic layer 13 are antiferromagnetically coupled. In this way, the reference layer 34 has a ferromagnetic pinned layer (SAF layer), and the first magnetic layer 11 and the second magnetic layer 13 have high perpendicular magnetic anisotropy, so that the thermal stability is good and writing errors are suppressed even when the element size is miniaturized.

[0050] <Eighth embodiment> 7 is a cross-sectional view showing an outline of an SOT-MRAM according to an eighth embodiment of the present invention. An SOT-MRAM 40 according to the eighth embodiment of the present invention includes a conductive layer 41 and a magnetoresistance effect element 46. The magnetoresistance effect element 46 is provided on the conductive layer 41, and includes a recording layer 42, a tunnel barrier layer 43, and a reference layer 44.

[0051] The reference layer 44 includes any of the various laminated films 10 described above (for example, the laminated film 10 shown in FIG. 1, the laminated film 10C shown in FIG. 3A, and the laminated film 10D shown in FIG. 3B), and is configured by laminating at least a first magnetic layer 11, an antiferromagnetic coupling layer 12, and a second magnetic layer 13 in this order. The first magnetic layer 11 is provided between the tunnel barrier layer 43 and the antiferromagnetic coupling layer 12 (for example, the interlayer coupling layer 12a or the nonmagnetic layer 12d). The second magnetic layer 13 is provided between the antiferromagnetic coupling layer 12 (for example, the interlayer coupling layer 12a or the nonmagnetic layer 12d, 12e) and the cap layer 45. Note that the details of the antiferromagnetic coupling layer 12 are not shown in FIG. 7.

[0052] The recording layer 42 includes a layer that is magnetization reversible and has perpendicular magnetic anisotropy. The tunnel barrier layer 43 is made of MgO or the like, and is provided between the recording layer 42 and the first magnetic layer 11.

[0053] The conductive layer 41 may include a laminate of a βW layer and a βTa layer, or may include a synthetic AF layer having a Pt layer and a Co / Pt / Ir / Pt / Co laminate film. As will be described in detail in the ninth and tenth embodiments below, the use of the laminate film 10A of the second embodiment or the laminate film 10B of the third embodiment will further improve the perpendicular magnetic anisotropy.

[0054] A first terminal T1 and a second terminal T2 are provided on the conductive layer 41 or are electrically connected to the conductive layer 41, a first transistor Tr1 is connected to the first terminal T1, and the second terminal T2 is grounded via a second transistor (not shown) as necessary. A cap layer 45 is provided on the reference layer 44, a third terminal T3 is provided on the cap layer 45, and the third transistor Tr3 is connected to the third terminal T3. The first terminal T1 is disposed on the opposite side to the second terminal T2, with the recording layer 42, the tunnel barrier layer 43, and the reference layer 44 in between.

[0055] When the first transistor Tr1 is in the ON state, the write voltage V W to the first terminal T1 to pass a current between the first terminal T1 and the second terminal T2, thereby passing a pin-localized current through the conductive layer 41. Then, the magnetization of the recording layer 42 can be reversed by the spin-orbit torque.

[0056] When the third transistor Tr3 is in the ON state, the read voltage V Read to the third terminal T3 to pass a current between the second terminal T2 and the third terminal T3. Depending on the magnitude of the current, data "0" or "1" corresponding to whether the magnetizations in the recording layer 42 and the reference layer 44 are parallel or antiparallel can be read out.

[0057] The SOT-MRAM 40 according to the eighth embodiment of the present invention includes the magnetoresistance effect element 30 according to the seventh embodiment of the present invention. That is, the reference layer 44 is configured by laminating the first magnetic layer 11, the antiferromagnetic coupling layer 12, and the second magnetic layer 13 in this order, and the first magnetic layer 11 and the second magnetic layer 13 are antiferromagnetically coupled. In this way, the reference layer 44 has a ferromagnetic pinned layer (SAF layer), and the first magnetic layer 11 and the second magnetic layer 13 have high perpendicular magnetic anisotropy, so that the thermal stability is good. As a result, the perpendicular magnetization of the first magnetic layer 11 and the second magnetic layer 13 can be more fixed and pinned. This makes it possible to reduce write errors even when the element is miniaturized. In this way, the SOT-MRAM 40 has three terminals consisting of the first terminal T1, the second terminal T2, and the third terminal T3. The SOT-MRAM 40 is configured such that, when a write current flows through the conductive layer 41, the direction of magnetization in the recording layer 42 is reversed.

[0058] <Ninth embodiment> 8 is a cross-sectional view showing an outline of an SOT-MRAM according to a ninth embodiment of the present invention. The SOT-MRAM 50 according to the ninth embodiment of the present invention includes a conductive layer 52 including any one of the various laminated films 10 described above (for example, the laminated film 10A according to the second embodiment of the present invention and the laminated film 10B according to the third embodiment of the present invention) and a magnetoresistance effect element 57. The magnetoresistance effect element 57 is provided on the conductive layer 52, and is configured by laminating a recording layer 53, a tunnel barrier layer 54, and a reference layer 55 in this order.

[0059] The conductive layer 52 includes a first magnetic layer 11, an antiferromagnetic coupling layer 12, and a second magnetic layer 13. The antiferromagnetic coupling layer 12 is provided between the first magnetic layer 11 and the second magnetic layer 13. The antiferromagnetic coupling layer 12 shown in FIG. 8 includes an Ir-Re alloy layer (interlayer coupling layer 12a), a first nonmagnetic layer 12b adjacent to a first surface (lower surface in the figure) of the Ir-Re alloy layer (interlayer coupling layer 12a), and a second nonmagnetic layer 12c adjacent to a second surface (upper surface in the figure) of the Ir-Re alloy layer (interlayer coupling layer 12a). The first nonmagnetic layer 12b and the second nonmagnetic layer 12c include a Pt layer or a Pt-Pd alloy layer. The conductive layer 52 is provided on the seed layer 51.

[0060] The conductive layer 52 includes a stack structure of the first magnetic layer 11 / the first non-magnetic layer 12b / the interlayer coupling layer 12a / the second non-magnetic layer 12c / the second magnetic layer 13. The spin Hall angle becomes large and the first magnetic layer 11 and the second magnetic layer 13 are antiferromagnetically coupled, thereby reducing the leakage magnetic field.

[0061] The recording layer 53 includes a layer having reversible magnetization and perpendicular magnetic anisotropy. The tunnel barrier layer 54 is sandwiched between the recording layer 53 and the reference layer 55. The reference layer 55 includes a ferromagnetic layer having perpendicular magnetic anisotropy and whose magnetization is fixed.

[0062] A first terminal T1 and a second terminal T2 are provided on the conductive layer 52 or are electrically connected to the conductive layer 52, and a first transistor Tr1 is connected to the first terminal T1 and is grounded to the second terminal T2 via a second transistor (not shown) as necessary. A cap layer 56 is provided on the reference layer 55, and a third terminal T3 is provided on the cap layer 56 and the third transistor Tr3 is connected to the third terminal T3. The first terminal T1 is disposed on the opposite side to the second terminal T2 with the recording layer 53, the tunnel barrier layer 54 and the reference layer 55 interposed therebetween.

[0063] When the first transistor Tr1 is in the ON state, the write voltage V W to the first terminal T1 to pass a current between the first terminal T1 and the second terminal T2, thereby passing a pin-localized current through the conductive layer 52. Then, the magnetization of the recording layer 53 can be reversed by the spin-orbit torque.

[0064] When the third transistor Tr3 is in the ON state, the read voltage V Read to the third terminal T3 to pass a current between the second terminal T2 and the third terminal T3. Depending on the magnitude of the current, data "0" or "1" corresponding to whether the magnetizations in the recording layer 53 and the reference layer 55 are parallel or anti-parallel can be read out.

[0065] In the SOT-MRAM 50 according to the ninth embodiment of the present invention, the conductive layer 52 includes the laminated film 10B according to the third embodiment of the present invention. Therefore, in the conductive layer 52, the perpendicular magnetic anisotropy of the first magnetic layer 11 and the second magnetic layer 13 is increased and the thermal stability is good. The spin-Hall angle is increased, and the first magnetic layer 11 and the second magnetic layer 13 are antiferromagnetically coupled, thereby reducing the leakage magnetic field. In this way, the SOT-MRAM 50 has three terminals consisting of the first terminal T1, the second terminal T2, and the third terminal T3. The SOT-MRAM 50 is configured such that the direction of magnetization in the recording layer 53 is reversed by the flow of a write current through the conductive layer 52.

[0066] In the ninth embodiment of the present invention, the conductive layer 52 may have the laminated film 10A according to the second embodiment of the present invention. That is, the conductive layer 52 may have a stack structure of the first magnetic layer 11 / the non-magnetic layer 12b / the Ir-Re alloy layer (interlayer coupling layer) 12a / the second magnetic layer 13. The spin Hall angle is increased, and the first magnetic layer 11 and the second magnetic layer 13 are antiferromagnetically coupled to each other, thereby reducing the leakage magnetic field. The conductive layer 52 may have a stack structure of the first magnetic layer 11 / the Ir-Re alloy layer (interlayer coupling layer) 12a / the non-magnetic layer 12b / the second magnetic layer 13. Even in this case, the spin Hall angle is increased, and the first magnetic layer 11 and the second magnetic layer 13 are antiferromagnetically coupled to each other, thereby reducing the leakage magnetic field.

[0067] <Tenth embodiment> 9 is a cross-sectional view showing an outline of an SOT-MRAM according to a tenth embodiment of the present invention. An SOT-MRAM 60 according to the tenth embodiment of the present invention includes a conductive layer 62 including the laminated film 10B according to the third embodiment of the present invention, and a magnetoresistance effect element 67. The magnetoresistance effect element 67 is provided on the conductive layer 62, and is configured by laminating a recording layer 63, a tunnel barrier layer 64, and a reference layer 65 in this order. The reference layer 65 includes any one of the various laminated films 10 described above (for example, the laminated film 10 according to the first embodiment of the present invention, the laminated film 10C shown in FIG. 3A, and the laminated film 10D shown in FIG. 3B).

[0068] The conductive layer 62 includes a first magnetic layer 11, an antiferromagnetic coupling layer 12, and a second magnetic layer 13. The antiferromagnetic coupling layer 12 is provided between the first magnetic layer 11 and the second magnetic layer 13. The antiferromagnetic coupling layer 12 shown in FIG. 9 includes an Ir-Re alloy layer (interlayer coupling layer 12a), a first nonmagnetic layer 12b adjacent to a first surface (lower surface in the figure) of the Ir-Re alloy layer (interlayer coupling layer 12a), and a second nonmagnetic layer 12c adjacent to a second surface (upper surface in the figure) of the Ir-Re alloy layer (interlayer coupling layer 12a). The first nonmagnetic layer 12b and the second nonmagnetic layer 12c include a Pt layer or a Pt-Pd alloy layer. The conductive layer 62 is provided on the seed layer 61.

[0069] The conductive layer 62 includes a stack structure of the first magnetic layer 11 / the first non-magnetic layer 12b / the interlayer coupling layer 12a / the second non-magnetic layer 12c / the second magnetic layer 13. The spin Hall angle becomes large and the first magnetic layer 11 and the second magnetic layer 13 are antiferromagnetically coupled, thereby reducing the leakage magnetic field.

[0070] The reference layer 65 includes any of the various laminated films 10 described above (for example, the laminated film 10 shown in FIG. 1, the laminated film 10C shown in FIG. 3A, and the laminated film 10D shown in FIG. 3B), and is configured by laminating at least the first magnetic layer 11x, the antiferromagnetic coupling layer 12x, and the second magnetic layer 13x in this order, and the first magnetic layer 11x and the second magnetic layer 13x are antiferromagnetically coupled. In this way, the reference layer 65 has a ferromagnetic pinned layer (SAF layer), and the first magnetic layer 11x and the second magnetic layer 13x have high perpendicular magnetic anisotropy, so that the thermal stability is good and writing errors are suppressed. The first magnetic layer 11x is provided between the tunnel barrier layer 64 and the antiferromagnetic coupling layer 12x. The second magnetic layer 13x is provided between the antiferromagnetic coupling layer 12x and the cap layer 66. The recording layer 63 is configured to include a magnetic layer that is magnetization reversible and has perpendicular magnetic anisotropy. In FIG. 9, the details of the antiferromagnetic coupling layer 12x are not shown.

[0071] A first terminal T1 and a second terminal T2 are provided on the conductive layer 62 or are electrically connected to the conductive layer 62, and a first transistor Tr1 is connected to the first terminal T1 and a second terminal T2 is grounded via a second transistor (not shown) as necessary. A cap layer 66 is provided on the reference layer 65, and a third terminal T3 is provided on the cap layer 66 and the third transistor Tr3 is connected to the third terminal T3. The first terminal T1 is disposed on the opposite side to the second terminal T2 with the recording layer 63, the tunnel barrier layer 64 and the reference layer 65 interposed therebetween.

[0072] When the first transistor Tr1 is in the ON state, the write voltage V W to the first terminal T1 to pass a current between the first terminal T1 and the second terminal T2, thereby passing a pin-localized current through the conductive layer 62. Then, the magnetization of the recording layer 63 can be reversed by the spin-orbit torque.

[0073] When the third transistor Tr3 is in the ON state, the read voltage V Read to the third terminal T3 to pass a current between the second terminal T2 and the third terminal T3. Depending on the magnitude of the current, data "0" or "1" corresponding to whether the magnetizations in the recording layer 63 and the reference layer 65 are parallel or anti-parallel can be read out.

[0074] In the tenth embodiment of the present invention, the reference layer 65 includes any of the various laminated films 10 described above (for example, the laminated film 10 according to the first embodiment of the present invention, the laminated film 10C shown in FIG. 3A, and the laminated film 10D shown in FIG. 3B). The reference layer 65 is configured by laminating the first magnetic layer 11x, the antiferromagnetic coupling layer 12x, and the second magnetic layer 13x in this order, and the first magnetic layer 11x and the second magnetic layer 13x are antiferromagnetically coupled. In this way, the reference layer 65 has a ferromagnetic pinned layer (SAF layer), and the first magnetic layer 11x and the second magnetic layer 13x have high perpendicular magnetic anisotropy, so that the thermal stability is good. As a result, the perpendicular magnetization of the first magnetic layer 11x and the second magnetic layer 13x can be more fixed and pinned. This makes it possible to reduce write errors even when the element is miniaturized. Thus, the SOT-MRAM 60 has three terminals, namely, the first terminal T1, the second terminal T2, and the third terminal T3. The SOT-MRAM 60 is configured such that, when a write current flows through the conductive layer 62, the direction of magnetization in the recording layer 63 is reversed.

[0075] In the tenth embodiment of the present invention, the conductive layer 62 includes the laminated film 10B according to the third embodiment of the present invention. Therefore, in the conductive layer 62, the perpendicular magnetic anisotropy of the first magnetic layer 11 and the second magnetic layer 13 is increased and the thermal stability is good. The spin Hall angle is increased and the first magnetic layer 11 and the second magnetic layer 13 are antiferromagnetically coupled, thereby reducing the leakage magnetic field.

[0076] In the tenth embodiment of the present invention, the conductive layer 62 may include the laminated film 10A according to the second embodiment of the present invention. That is, the conductive layer 62 has a stack structure of the first magnetic layer 11 / the non-magnetic layer 12b / the Ir-Re alloy layer (interlayer coupling layer) 12a / the second magnetic layer 13. The spin Hall angle is increased, and the first magnetic layer 11 and the second magnetic layer 13 are antiferromagnetically coupled to each other, thereby reducing the leakage magnetic field. The conductive layer 62 may also have a stack structure of the first magnetic layer 11 / the Ir-Re alloy layer (interlayer coupling layer) 12a / the non-magnetic layer 12b / the second magnetic layer 13. Even in this case, the spin Hall angle is increased, and the first magnetic layer 11 and the second magnetic layer 13 are antiferromagnetically coupled to each other, thereby reducing the leakage magnetic field.

[0077] Next, the verification results will be shown to explain that in the laminate films 10, 10A, 10B, etc. according to each embodiment of the present invention, the interlayer bonding layer 12a includes a layer made of an Ir-Re alloy, and the Re atomic ratio in the Ir-Re alloy is preferably greater than 0% and less than or equal to about 12.5%.

[0078] <Verification Experiment 1> In verification experiment 1, the interlayer bonding layer was an Ir layer, and the thickness t Ir A number of samples were fabricated with thicknesses ranging from 0.4 nm to 1.6 nm in 0.1 nm increments. Figure 10A shows the structure of a sample in verification experiment 1. Using a Si substrate with a thermal oxide film, a 3.0 nm Ta layer was formed on the thermal oxide film, a 3.0 nm Pt layer was formed on the Ta layer, and four 0.5 nm Co layers and 0.25 nm Pt layers were alternately formed on the Pt layer. A 0.5 nm Co layer and a 0.25 nm Pt layer were then formed. Ir An Ir layer of 0.1 nm and a Co layer of 0.5 nm were formed in this order, and then four Pt layers of 0.25 nm and four Co layers of 0.5 nm were formed alternately, and a Pt layer of 3 nm was further formed.

[0079] <Verification Experiment 2> In verification experiment 2, the interlayer bonding layer was Ir 75 Re 25 The Ir layer is sandwiched between 0.5 nm Co layers on top and bottom. 75 Re25 Layer thickness t IrRe A number of samples were fabricated with thicknesses ranging from 0.4 nm to 1.6 nm in 0.1 nm increments. Figure 10B shows the structure of a sample in verification experiment 2. Using a Si substrate with a thermal oxide film, a 3.0 nm Ta layer was formed on the thermal oxide film, a 2.0 nm Pt layer was formed on the Ta layer, and a 1 nm Ir layer was formed on the Pt layer. 75 Re 25 A layer is provided, and Ir 75 Re 25 Four 0.5 nm Co layers and 0.25 nm Pt layers are alternately formed on the layer, and then four 0.5 nm Co layers and t IrRe Ir 75 Re 25 A 0.25 nm Pt layer and a 0.5 nm Co layer are then formed in this order, followed by four alternating 0.25 nm Pt layers and 0.5 nm Co layers, and then a 1 nm Ir layer. 75 Re 25 A layer and a 3 nm thick Pt layer were then provided in this order.

[0080] <Verification Experiment 3> In verification experiment 3, the interlayer bonding layer was Ir 75 Re 25 The Ir layer is sandwiched between 0.5 nm Co layers on top and bottom. 75 Re 25 Layer thickness t IrRe A number of samples were fabricated with thicknesses ranging from 0.4 nm to 1.6 nm in 0.1 nm increments. Figure 10C shows the structure of a sample in verification experiment 3. Using a Si substrate with a thermal oxide film, a 3.0 nm Ta layer was formed on the thermal oxide film, a 3.0 nm Pt layer was formed on the Ta layer, and four 0.5 nm Co layers and 0.25 nm Pt layers were alternately formed on the Pt layer. Furthermore, a 0.5 nm Co layer, a t IrRe Ir 75 Re 25 A 0.25 nm Pt layer and a 0.5 nm Co layer were formed in this order, and four 0.25 nm Pt layers and four 0.5 nm Co layers were formed alternately, followed by a 3 nm Pt layer.

[0081] The MH curve (magnetization curve) was measured for each sample produced in the verification experiments 1 to 3. Ir11B is the MH curve of the sample with Ir 97.5 Re 2.5 The film thickness t IrRe This is the MH curve for a sample with a magnetic field of 0.4 nm. The horizontal axis is the applied magnetic field H (T), and the vertical axis is M / Ms. Ms is the saturation value, and Hex is the exchange coupling magnetic field. "In-plane" is when the applied magnetic field is in-plane, and "out-of-plane" is when the magnetic field is perpendicular to the surface (magnetic field perpendicular to the surface).

[0082] 11A and 11B, it is found that by forming the interlayer coupling layer with an IrRe alloy, Hex is large and magnetization reversal does not occur unless the external magnetic field is increased, so the exchange coupling strength between the upper and lower ferromagnetic layers is increased. In addition, the magnetic field at which the magnetization increases in Fig. 11B is steeper than the magnetization curve in Fig. 11A, which makes it clear that mixing Ir with Re increases the perpendicular magnetic anisotropy.

[0083] The interlayer bond strength J in each sample produced in verification experiments 1 to 3 ex (mJ / m 2 ) was obtained. The measurement environment was room temperature. FIG. 12 is a diagram showing the dependence of the interlayer interaction on the Ir or IrRe film thickness for Verification Experiment 1 and Verification Experiment 2. The horizontal axis of the figure is the Ir film thickness t Ir or the thickness of IrRe, t IrRe The vertical axis represents the interlayer bonding strength |J ex The black circles plot data when the interlayer bonding layer is an Ir layer, and the black squares plot data when the interlayer bonding layer is an Ir layer. 75 Re 25 This is data for the case where

[0084] In the IrRe interlayer coupling layer as in Verification Experiment 2, the position of the antiparallel alignment (AF) peak was observed to shift by about 0.3 nm toward the thinner layer side (to the left in the figure) compared to the Ir interlayer coupling layer in Verification Experiment 1. When the Re concentration was as high as 25%, the shift was large and the 1st peak was not observed.

[0085] 13A to 13C show MH curves for each sample in verification experiments 1 to 3, in which the thickness of the interlayer coupling layer is 0.8 nm, and FIG. 14A to 14C show MH curves for each sample in verification experiments 1 to 3, in which the thickness of the interlayer coupling layer is 1.4 nm. The horizontal axis is the applied magnetic field H (mT), and the vertical axis is M / Ms. Note that 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 plane (magnetic field perpendicular to the plane).

[0086] As can be seen from FIG. 13A to FIG. 13C, the thickness t Ir , t IrRe When the thickness t of the interlayer coupling layer is 0.8 nm, the upper and lower Co layers are ferromagnetically coupled. Ir , t IrRe When the thickness is 1.4 nm, the upper and lower Co layers are in an antiferromagnetically coupled state.

[0087] In the ferromagnetically coupled state, the thickness of the interlayer coupling layer t Ir , t IrRe When the thickness is 0.8 nm, the interlayer bonding layer is Ir 75 Re 25 It was found that when the interlayer coupling layer was a layer, the anisotropy field Hk was larger and the perpendicular magnetic anisotropy was increased compared to when the interlayer coupling layer was an Ir layer.

[0088] In the antiferromagnetic coupling state, the thickness of the interlayer coupling layer t Ir , t IrRe When the thickness is 1.4 nm, the interlayer bonding layer is Ir 75 Re 25 It was found that when the interlayer coupling layer was a layer, the anisotropy field Hk was larger and the perpendicular magnetic anisotropy was increased compared to when the interlayer coupling layer was an Ir layer.

[0089] Therefore, in both the ferromagnetically coupled and antiferromagnetically coupled states, an increase in Hk of MH in the hard axis direction was confirmed, which confirmed an increase in perpendicular magnetic anisotropy.

[0090] When an underlayer of an IrRe alloy was provided, as in the sample prepared in verification experiment 2, it was found that the presence or absence of an IrRe layer did not affect the increase in perpendicular magnetic anisotropy, compared to when no underlayer was provided, as in the sample prepared in verification experiment 3.

[0091] <Verification Experiment 4> In verification experiment 4, the interlayer bonding layer was Ir x Re y The values ​​of x and y were x=98.5, y=1.5, x=97.5, y=2.5, x=95.5, y=4.5, x=91.5, y=8.5, x=83.5, y=16.5, and x=100, y=0 as a comparative example. x Re y Layer thickness t IrRe Multiple samples were prepared with the thickness ranging from 0.3 nm to 0.6 nm in increments of 0.1 nm or 0.05 nm.

[0092] FIG. 15 is a diagram showing the structure of a sample in verification experiment 4. Using a Si substrate having a thermal oxide film, a 3.0 nm Ta layer was formed on the thermal oxide film, a 3.0 nm Pt layer was formed on the Ta layer, and four 0.5 nm Co layers and 0.25 nm Pt layers were alternately formed on the Pt layer. IrRe Ir x Re y A 0.25 nm Pt layer and a 0.5 nm Co layer were formed in this order, and four 0.25 nm Pt layers and four 0.5 nm Co layers were formed alternately, followed by a 1 nm Ir layer and a 2 nm Ta layer. 97.5 Re 2.5 Film thickness t IrRe The graph shows the MH curve of a sample with a thickness of 0.4 nm.

[0093] FIG. 16A shows the results of MH measurements of a sample having an Ir interlayer coupling layer and antiferromagnetic coupling and a thickness of 0.5 nm, after annealing at 300° C. in a vacuum for 1 hour. 95.5 Re 4.5FIG. 16C shows the results of MH measurements on a sample with an antiferromagnetically coupled interlayer of 0.45 nm thickness after annealing at 300° C. in vacuum for 1 hour. 91.5 Re 8.5 17A shows the MH measurement results of a sample having an Ir interlayer coupling layer and a thickness of 0.5 nm, which is antiferromagnetically coupled, after annealing in a vacuum for 1 hour at 300° C. FIG. 17B shows the MH measurement results of a sample having an Ir interlayer coupling layer and a thickness of 0.45 nm, which is antiferromagnetically coupled, after annealing in a vacuum for 1 hour at 400° C. FIG. 95.5 Re 4.5 FIG. 17C shows the results of MH measurements on a sample with an antiferromagnetically coupled interlayer of 0.45 nm thickness after annealing at 400° C. in vacuum for 1 hour. 91.5 Re 8.5 The results are shown in Fig. 13. The MH measurements were performed on a 0.5 nm thick sample of antiferromagnetically coupled interlayers after annealing in vacuum for 1 hour at 400° C. The thickness of the interlayer coupling layer is the thickness at the first peak.

[0094] 16A to 16C and 17A to 17C, it was found that the perpendicular magnetic anisotropy is stronger when the interlayer coupling layer is IrRe than when the interlayer coupling layer is Ir. The same results were obtained for samples not shown in FIGS. 16A to 16C and 17A to 17C.

[0095] FIG. 18A shows the thickness of IrRe in the sample annealed at 300° C. in vacuum for 1 hour in verification experiment 4. IrRe Interlaminar bond strength |J ex |(mJ / m 2 ) IrRe film thickness t IrRe FIG. 18B is a graph showing the dependence of the thickness t of IrRe on the sample annealed at 400° C. in a vacuum for 1 hour in verification experiment 4. IrRe Interlaminar bond strength |J ex |(mJ / m 2 ) IrRe film thickness t IrRe Table 1 shows the dependence of the interlayer bonding layer on the x Re yThe interlaminar bond strength |J of each sample when it was constructed by ex |(mJ / m 2 Table 2 shows the interlayer bonding layer as Ir x Re y The interlaminar bond strength |J of each sample when it was constructed by ex |(mJ / m 2 In Tables 1 and 2, "-" indicates that the data was not created.

[0096] t IrRe Since this is the first peak value for AF bonding, it was found that the interlayer bonding strength is large if the interlayer bonding layer has a composition containing Ir with a small amount of Re.

[0097] FIG. 19A shows the thickness of the film IrRe 0.4 nm interlayer bonding layer Ir 97.5 Re 2.5 The MH measurement results of the sample after annealing at 300° C. are shown in FIG. IrRe A 0.4 nm interlayer bonding layer of Ir 97.5 Re 2.5 This shows the results of MH measurements of the sample after annealing at 400° C. It was confirmed that the magnetic layer exhibited perpendicular magnetic anisotropy, and that antiferromagnetic coupling occurred between the Co atoms in the magnetic layer.

[0098] FIG. 20A shows the thickness of the film IrRe 0.35 nm interlayer bonding layer Ir 98.5 Re 1.5 FIG. 20B shows the MH measurement results after annealing the sample at 300° C. IrRe 0.35 nm Ir bonding layer 98.5 Re 1.5 The results are shown in the MH measurement results after annealing the sample at 400°C. It was confirmed that the magnetic layer exhibited perpendicular magnetic anisotropy and that antiferromagnetic coupling occurred between the Co layers in the magnetic layer. 98.5 Re 1.5 The sample with a layer structure has an Ir interlayer bonding layer. 97.5 Re 2.5When compared with the sample that is a layer, it was confirmed that the heat resistance at 400 °C was improved. Therefore, the laminated film according to the embodiment of the present invention has heat resistance of 300 °C to 400 °C.

[0099] Figure 21 is a diagram showing the dependence of the interfacial bonding strength on the Re composition. The horizontal axis is the composition (concentration) atomic % of Re, and the vertical axis is the interfacial bonding strength |J ex | (mJ / m 2 ). The black circle (●) plots are for the samples annealed at 300 °C, and the black square (■) plots are for the samples annealed at 400 °C.

[0100] The interfacial bonding strength |J ex | of 1.0 (mJ / m 2 ) is a sufficient value. For the interfacial bonding layer of Ir x Re y (where x + y = 100 and 0 < x, y < 100), 0 < y ≤ 12.5 is preferable. y is preferably 10 or less. y is preferably 8.5 or less. Further, y is preferably 4.5 or less. The minimum value of y only needs to contain Re, and y is preferably 0.05 or more. Further, y is preferably 0.1 or more.

[0101]

Table 1

[0102]

Table 2

[0103] As described above, since the interfacial bonding strength is preferably 1.0 mJ / m 2 or more, the following film thickness ranges can be used. For the interfacial bonding layer of Ir x Re y where y = 1.5, and the film thickness t IrxRey is thicker than 0.3 nm and preferably 0.6 nm or less. For the interfacial bonding layer of Ir x Re y where y = 2.5, and the film thickness tIrxRey It is preferable that the thickness is 0.35 nm or more and 0.55 nm or less. Interlayer bonding layer Ir x Re y In this case, y=4.5 and the film thickness t IrxRey The thickness is preferably greater than 0.4 nm and less than 0.55 nm. Interlayer bonding layer Ir x Re y In this case, y=8.5 and the film thickness t IrxRey It is preferable that the thickness is not less than 0.45 nm and not more than 0.55 nm. Even when the known Ru or Ir layers are used, the interlayer bonding strength is 1.0 mJ / m within the above-mentioned film thickness range. 2 Although the above results are obtained, in terms of perpendicular magnetic anisotropy and heat resistance to 400° C., more preferable results are obtained when IrRe is used.

[0104] Furthermore, within the film thickness range of the following composition, the interlayer bonding strength is greater than in the case where an Ir layer is used as a known example, and more preferable effects are obtained. Interlayer bonding layer Ir x Re y In this case, y=1.5 and the film thickness t IrxRey It is preferable that the thickness is 0.32 nm or more and 0.5 nm or less. Interlayer bonding layer Ir x Re y In this case, y=2.5 and the film thickness t IrxRey is preferably 0.35 nm or more and 0.5 nm or less. Interlayer bonding layer Ir x Re y In this case, y=4.5 and the film thickness t IrxRey A value of 0.45 nm is recommended.

[0105] <Verification Experiment 5> In verification experiment 5, several samples were fabricated assuming conductive layers for SOT-MRAM (wiring layers for SOT-MRAM). 95.5 Re 4.5The thickness of the interlayer bonding layer was set to 0.45 nm, and the thicknesses of the upper and lower Pt layers sandwiching the interlayer bonding layer were set to 0.4 nm and 0.5 nm. Figure 22A shows the structure of the sample in verification experiment 5. Using a Si substrate with a thermal oxide film, a 2.0 nm Ta layer was formed on the thermal oxide film, a 2.0 nm Ir layer was formed on the Ta layer, a 1.1 nm Co layer was formed on the Ir layer, and a 1.1 nm thick Co layer was formed on the Co layer. Pt A Pt layer of 0.45 nm was then formed on the Pt layer. 95.5 Re 4.5 A layer is provided, and Ir 95.5 Re 4.5 Layer thickness t Pt A Pt layer of 1.1 nm was provided on the Pt layer, a Co layer of 1.1 nm was provided on the Pt layer, an Ir layer of 0.5 nm was provided on the Co layer, a MgO layer of 1.5 nm was provided on the Ir layer, and a Ta layer of 1.5 nm was provided on the MgO layer.

[0106] FIG. 23A shows the thickness t Pt 0.4 nm Pt layer and Ir interlayer 95.5 Re 4.5 It was confirmed that the magnetic layer exhibited perpendicular magnetic anisotropy.

[0107] FIG. 23B shows the interlayer bonding layer Ir 95.5 Re 4.5 MH curves of two samples with thickness t Pt A sample with a 0.4 nm thickness and a sample with a 0.5 nm Pt layer are shown. It was confirmed that the magnetic layer exhibited good perpendicular magnetic anisotropy and antiferromagnetic coupling.

[0108] <Verification Experiment 6> In verification experiment 6, several samples were fabricated assuming conductive layers for SOT-MRAM. 97.5 Re 2.5The thickness of the interlayer bonding layer was set to 0.4 nm, and the thicknesses of the upper and lower Pt layers sandwiching the interlayer bonding layer were set to 0.6 nm, 0.7 nm, and 0.8 nm. Figure 22B shows the structure of the sample in verification experiment 6. Using a Si substrate with a thermal oxide film, a 2.0 nm Ta layer was formed on the thermal oxide film, a 2.0 nm Ir layer was formed on the Ta layer, a 1.1 nm Co layer was formed on the Ir layer, and a 1.1 nm thick Co layer was formed on the Co layer. Pt A Pt layer of 0.4 nm was then formed on the Pt layer. 97.5 Re 2.5 A layer is provided, and Ir 97.5 Re 2.5 Layer thickness t Pt A Pt layer of 1.1 nm was provided on the Pt layer, a Co layer of 1.1 nm was provided on the Pt layer, an Ir layer of 0.5 nm was provided on the Co layer, a MgO layer of 1.5 nm was provided on the Ir layer, and a Ta layer of 1.5 nm was provided on the MgO layer.

[0109] FIG. 24A shows the thickness t Pt 0.6 nm Pt layer and Ir interlayer bonding layer 97.5 Re 2.5 MH curves of a sample having a magnetic layer, which shows that the magnetic layer exhibits perpendicular magnetic anisotropy.

[0110] FIG. 24B shows the interlayer bonding layer Ir 97.5 Re 2.5 MH curves of three samples with thickness t Pt Sample with 0.6 nm Pt layer, thickness t Pt Sample with 0.7 nm Pt layer, thickness t Pt The results are shown for a sample with a 0.8 nm Pt layer. It was confirmed that the magnetic layer in each sample exhibited good perpendicular magnetic anisotropy and antiferromagnetic coupling.

[0111] <Verification Experiment 7> In the seventh verification experiment, several samples were fabricated assuming conductive layers for SOT-MRAM. 98.5 Re 1.5The thickness is 0.35 nm, and samples with the thicknesses of the upper and lower Pt layers sandwiching the interlayer coupling layer being 0.6 nm, 0.7 nm, and 0.8 nm were fabricated. FIG. 22C is a diagram showing the structure of the sample in verification experiment 7. Using a Si substrate with a thermal oxide film, a 2.0 nm Ta layer was provided on the thermal oxide film, a 2.0 nm Ir layer was provided on the Ta layer, a 1.1 nm Co layer was provided on the Ir layer, and a Pt layer with thickness t Pt was provided on the Co layer, and a 0.35 nm Ir 98.5 Re 1.5 layer was provided on the Pt layer, and a Pt layer with thickness t 98.5 Re 1.5 was provided on the Ir Pt Re layer, a 1.1 nm Co layer was provided on the Pt layer, a 0.5 nm Ir layer was provided on the Co layer, a 1.5 nm MgO layer was provided on the Ir layer, and a 1.5 nm Ta layer was provided on the MgO layer.

[0112] FIG. 25A is the M-H curve of the sample having a Pt layer with thickness t Pt of 0.6 nm and an interlayer coupling layer Ir 98.5 Re 1.5 layer. It was confirmed that the magnetic layer exhibits good perpendicular magnetic anisotropy and antiferromagnetic coupling.

[0113] FIG. 25B is the M-H curve of three samples having an interlayer coupling layer Ir 98.5 Re 1.5 layer. Shown are the samples having a Pt layer with thickness t Pt of 0.6 nm, the sample having a Pt layer with thickness t Pt of 0.7 nm, and the sample having a Pt layer with thickness t Pt of 0.8 nm. It was confirmed that in any of the samples, the magnetic layer exhibits good perpendicular magnetic anisotropy and antiferromagnetic coupling.

[0114] As a result of verification experiments 5 to 7, it was found that a laminated film having an Ir x Re y layer (0 < y < 4.5) can be used as the conductive layer of SOT-MRAM.

[0115] As explained in the fourth embodiment of the present invention, an Ir layer was used for the nonmagnetic layer 12d, and the thickness of the nonmagnetic layer 12d and the Re composition in the layer 12a containing an Ir-Re alloy were adjusted so that the Ir and Re compositions when the layer 12a containing an Ir-Re alloy and the nonmagnetic layer 12d were considered as one were consistent with the preferred compositions in the first embodiment of the present invention, and multiple samples were fabricated in which the antiferromagnetic coupling layer 12 was within the preferred thickness range when the nonmagnetic layer 12d was not used. In this case as well, it was confirmed that the perpendicular magnetic anisotropy was increased and the thermal stability was good, as in the case when the nonmagnetic layer 12d was not used.

[0116] As described in the fifth embodiment of the present invention, the first non-magnetic layer 12d and the second non-magnetic layer 12e are both Ir layers, and the thicknesses of the first non-magnetic layer 12d and the second non-magnetic layer 12e and the composition of Re in the layer 12a containing an Ir-Re alloy are adjusted so that the composition of Ir and Re when the layer 12a containing an Ir-Re alloy, the first non-magnetic layer 12d, and the second non-magnetic layer 12e are considered as one unit coincides with the preferred composition in the first embodiment of the present invention, and a plurality of samples are fabricated in which the antiferromagnetic coupling layer 12 is in the preferred thickness range when neither the first non-magnetic layer 12d nor the second non-magnetic layer 12e is used. In this case, as in the case when the non-magnetic layer 12d is not used, it was confirmed that the perpendicular magnetic anisotropy is increased and the thermal stability is good.

[0117] The semiconductor memory and logic LSI including the MRAM according to the embodiment of the present invention can be configured by using the laminated film according to the first to fifth embodiments of the present invention and by providing a plurality of magnetoresistance effect elements (including SOT-MRAM) according to the sixth to tenth embodiments of the present invention. The magnetoresistance effect element according to the embodiment of the present invention, the semiconductor memory including the MRAM according to the embodiment of the present invention, and the logic LSI according to the embodiment of the present invention all use the laminated film according to the first to fifth embodiments of the present invention, so that the thickness of the layer including Ir and Re in the antiferromagnetic coupling layer 12 in the magnetoresistance effect element according to the embodiment of the present invention, the semiconductor memory including the MRAM according to the embodiment of the present invention, and the logic LSI according to the embodiment of the present invention (for example, the interlayer coupling layer 12a, the layer consisting of the interlayer coupling layer 12a and the nonmagnetic layer 12d, and the layer consisting of the nonmagnetic layer 12d, the interlayer coupling layer 12a, and the nonmagnetic layer 12e) is greater than 0.2 nm and smaller than 1.0 nm. The details are the same as those described in the first embodiment. The magnetoresistance effect element, the semiconductor memory, and the logic LSI have one or more laminated films according to the embodiment of the present invention.

[0118] <Comparative Experiment 1> In Comparative Experiment 1, the interlayer bonding layer was a Ru layer, and several samples with different thicknesses were tested (Co / Pt / Ru). 2 / Co and (Co / Pt) 4.5 / Ru / (Co / Pt) 4.5 A sample having an interlayer bond strength |J ex Figure 26 shows the interlayer bonding strength |J ex The horizontal axis is the Ru layer thickness (nm), and the vertical axis is the interlayer bonding strength |J ex The black circle plot is (Co / Pt / Ru) 2 / Co, the diamond plot is (Co / Pt) 4.5 / Ru / (Co / Pt) 4.5 The thickness of the Ru layer in each plot is t Ruare 0.4nm, 0.5nm, 0.6nm, 0.7nm, 0.8nm, 0.9nm, 1.0nm, 1.1nm, 1.2nm, 1.4nm, 1.5nm, 1.6nm, 1.7nm, 1.8nm, 1.9nm, 2.0nm, 2.1nm, and 2.2nm. It was found that the vibration caused by the interaction between Ru layers corresponding to the interlayer exchange vibration period Λ1 is eliminated by sandwiching Pt. Therefore, when Pt is diffused so as to contact Co by 400°C heat treatment, a large variation occurs in the interlayer bonding strength. Therefore, when a Ru layer is used as an interlayer bonding layer, the thickness of Ru is set to 1.5 nm, and the interlayer bonding strength |J ex It is necessary to select the thickness at which the second peak of | occurs.

[0119] In contrast to this, as shown in the above-mentioned FIGS. 18A and 18B, by forming the interlayer bonding layer from an Ir--Re alloy in which Ir contains a small amount of Re, the thickness of the first peak can be selected.

[0120] <Comparative experiment 2> In comparative experiment 2, the interlayer bonding layer was an Ir layer, and several samples with different thicknesses were tested (Co / Pt / Ir). 2 / Co and (Co / Pt) 4.5 / Ir / (Co / Pt) 4.5 A sample having an interlayer bond strength |J ex The interlayer bonding strength |J ex The horizontal axis is the thickness of the Ir layer (nm), and the vertical axis is the interlayer bonding strength |J ex The black circle plot is (Co / Pt) 4.5 / Ir / (Co / Pt) 4.5 The diamond plot is (Co / Pt / Ir) 2 / Co. The thickness of the Ir layer in each plot is t Ir is in 0.1 nm increments, such as 0.4 nm, 0.5 nm, 0.6 nm, 0.7 nm, 0.8 nm, 0.9 nm, 1.0 nm, 1.1 nm, 1.2 nm, 1.3 nm, 1.4 nm, 1.5 nm, and 1.6 nm, and only the diamond plot includes 0.55 nm. Interlayer bonding strength |J exIt was found that even if a Pt layer was inserted as a non-magnetic layer between the interlayer coupling layer and the ferromagnetic layer, the antiferromagnetic coupling was maintained.

[0121] 26 with FIG. 27, the exchange coupling strength between the first magnetic layer and the second magnetic layer via the interlayer coupling layer made of a Ru layer is stronger than the exchange coupling strength between the first magnetic layer and the second magnetic layer via the coupling layer made of an Ir layer. However, even a small amount of contact between the Ru atoms constituting the interlayer coupling layer and the Pt atoms constituting a part of the first magnetic layer or the second magnetic layer weakens the interlayer coupling strength between the first magnetic layer and the second magnetic layer, and the thermal stability is poor.

[0122] When the interlayer coupling layer is a layer made of only Ir, the first peak does not disappear as in the case where the interlayer coupling layer is a layer made of only Ru. However, Ir is known to be expensive as a material for the interlayer coupling layer. Since Re is cheaper than Ir, it is also advantageous that mass production costs can be reduced. In the laminated film according to some embodiments of the present invention, the interlayer coupling layer 12a is configured to include a layer made of an alloy of Ir and Re, so that the interlayer coupling layer 12a has a high exchange coupling strength between the first magnetic layer 11 and the second magnetic layer 13, the perpendicular magnetic anisotropy is increased, and the stability is good. In addition, the laminated film has a heat resistance of 400°C.

[0123] <Verification Experiment 8> In verification experiment 8, the antiferromagnetic coupling layer had a laminated structure of Re / Ir / Re, the atomic percentage of Re in the entire laminated structure was 1.6 atomic %, and the thickness of the antiferromagnetic coupling layer was t IrReA number of samples were fabricated in which the thicknesses of the layers were 0.4 nm, 0.45 nm, 0.5 nm, 0.55 nm, and 0.6 nm, and the Re / Ir / Re stack was sandwiched between 0.5 nm Co layers on both sides. FIG. 28A is a diagram showing the structure of a sample in verification experiment 8. Using a Si substrate with a thermal oxide film, a 5.0 nm Ta layer was provided on the thermal oxide film, a 6.0 nm Ru layer was provided on the Ta layer, a 2.0 nm Pt layer was provided on the Ru layer, and four layers of 0.5 nm Co layers and 0.3 nm Pt layers were provided alternately on the Pt layer, a 0.5 nm Co layer, a Re / Ir / Re stack, and a 0.5 nm Co layer were provided in this order, and four layers of 0.3 nm Pt layers and 0.5 nm Co layers were provided alternately, and a 3 nm Pt layer was provided. Then, the layers were annealed at 400° C. As a result, the stacked structure became an Ir-Re alloy.

[0124] <Verification Experiment 9> In verification experiment 9, the antiferromagnetic coupling layer had a laminated structure of Ir / Re / Ir, the atomic percentage of Re in the entire laminated structure was 1.6 atomic %, and the thickness of the antiferromagnetic coupling layer was t IrRe A number of samples were fabricated in which the thicknesses of the layers were 0.4 nm, 0.45 nm, 0.5 nm, 0.55 nm, and 0.6 nm, and the Ir / Re / Ir stack was sandwiched between 0.5 nm Co layers on both sides. FIG. 28B is a diagram showing the structure of a sample in verification experiment 9. Using a Si substrate with a thermal oxide film, a 5.0 nm Ta layer was provided on the thermal oxide film, a 6.0 nm Ru layer was provided on the Ta layer, a 2.0 nm Pt layer was provided on the Ru layer, and four layers of 0.5 nm Co layers and 0.3 nm Pt layers were alternately provided on the Pt layer, a 0.5 nm Co layer, a stack of Ir / Re / Ir, and a 0.5 nm Co layer were provided in this order, and four layers of 0.3 nm Pt layers and 0.5 nm Co layers were alternately provided, and a 3 nm Pt layer was provided. Then, the layers were annealed at 400° C. As a result, the stacked structure became an Ir-Re alloy.

[0125] <Comparative experiment 3> In the comparative experiment 3, the antiferromagnetic coupling layer was an Ir layer with a thickness of t IrSamples were fabricated in which the thicknesses of the Ir layers were 0.4 nm, 0.45 nm, 0.5 nm, 0.55 nm, and 0.6 nm, and the Ir layer was sandwiched between 0.5 nm Co layers on both sides. Fig. 28C is a diagram showing the structure of a sample in Comparative Experiment 3. Using a Si substrate with a thermal oxide film, a 5.0 nm Ta layer was formed on the thermal oxide film, a 6.0 nm Ru layer was formed on the Ta layer, a 2.0 nm Pt layer was formed on the Ru layer, and four 0.5 nm Co layers and 0.3 nm Pt layers were alternately formed on the Pt layer. Further, a 0.5 nm Co layer and a 0.5 nm thick Pt layer were formed on the Pt layer. Ir A 0.3 nm Ir layer and a 0.5 nm Co layer were formed in this order, and four 0.3 nm Pt layers and four 0.5 nm Co layers were formed alternately, followed by a 3 nm Pt layer. The film was then annealed at 400°C.

[0126] The MH curves were measured for each sample prepared in the verification experiments 8 and 9 and the comparative experiment 3. FIG. 29A shows the thickness t IrRe 29B shows the MH curve of the sample with the thickness t IrRe 29C is the MH curve of the sample with the Ir film thickness t Ir The horizontal axis is the applied magnetic field H(T) and the vertical axis is M / Ms. Ms is the saturation value, and H ex is the exchange coupling field. The applied field is out-of-plane.

[0127] The AF coupling exchange was observed in all samples at zero external magnetic field (H = 0 T). As shown in Fig. 29A and Fig. 29B, the samples with Re / Ir / Re and Ir / Re / Ir stacks had a higher exchange coupling magnetic field H ex was found to be large.

[0128] Figure 30 shows the thickness of the I-Re alloy after annealing in the samples in validation experiments 8 and 9. IrReand the thickness of Ir in sample 3 after annealing in comparative experiment 3, t Ir Interlaminar bonding strength as a function of |J ex The interlayer bond strength |J | is plotted for both the sample in verification experiment 8 and the sample in verification experiment 9. ex | is about 1.0 (mJ / m 2 ) was found to be larger than

[0129] As shown in FIG. 30, the interlayer bonding strength |J ex The maximum value of | is almost the same, about 2.7 (mJ / m 2 ) This means that, compared with the results of comparison experiment 3, strong AF bonds were observed in the samples in validation experiments 8 and 9. This is due to interdiffusion between Ir and Re atoms.

[0130] Furthermore, the thickness of the Ir-Re alloy in the annealed sample, t IrRe In the range of 0.45 nm to 0.6 nm, the interlayer bonding strength |J ex It turns out that the maximum value of | is much larger.

[0131] From this, as shown in verification experiments 8 and 9, the interlayer coupling strength |J ex It was found that | increased by about 30%. These results were similar to those explained with reference to Figures 18A, 18B, 21, etc.

[0132] As shown in FIG. 30, the interlayer bonding strength |J ex The film thickness at which the maximum value of | is observed is small.

[0133] In the embodiment of the present invention, the pin layer of the magnetoresistance effect element (MTJ element) includes a synthetic antiferromagnetic layer, so that the perpendicular magnetic anisotropy is strong and the thermal stability is good. Therefore, a high-density spin device can be provided. In addition, the coupling strength between the magnetic layers in the SAF layer is strong, so that writing errors due to backhopping are suppressed.

[0134] In the SOT-MRAM according to the embodiment of the present invention, a magnetoresistance effect element (MTJ element) is provided by stacking a recording layer, a tunnel barrier layer, and a reference layer in this order on a conductive layer, and the conductive layer is a synthetic antiferromagnetic layer. More specifically, the conductive layer has an antiferromagnetic coupling layer including a nonmagnetic layer and an interlayer coupling layer between a first magnetic layer and a second magnetic layer. The interlayer coupling layer includes a layer made of an Ir-Re alloy, so that it has strong antiferromagnetic coupling, strong perpendicular magnetic anisotropy, and good thermal stability. It also has heat resistance of 300°C to 400°C.

[0135] In order to fabricate a device including elements using the laminated film according to the embodiment of the present invention, a magnetic layer is formed, followed by heat treatment, a pattern for a magnetoresistance effect element (MTJ element) is generated, the magnetoresistance effect element is formed by etching, a protective film is formed thereon, and then an annealing treatment is performed at 300° C. to 400° C. to relieve stress or distortion in the magnetoresistance effect element and the protective film. Since the laminated film according to the embodiment of the present invention has heat resistance, even if the annealing treatment is performed, the antiferromagnetically coupled magnetic layer included in the reference layer maintains perpendicular magnetic anisotropy, and strong pinning can be performed.

[0136] <Eleventh embodiment> FIG. 31 is a diagram showing a semiconductor memory as an integrated circuit according to an eleventh embodiment of the present invention. As shown in FIG. 31, the semiconductor memory 1 is configured by arranging a plurality of memory cells 2 in an array. The semiconductor memory 1 includes an X driver 3 and a Y driver 4 adjacent to the memory array, and a controller 5 controls the X driver 3 and the Y driver 4. The array of memory cells 2 is arranged in, for example, M rows and M columns. The first bit line BL1 and the second bit line BL2 of the corresponding column are connected to the memory cell 2, and the memory cell 2 is connected to the word lines WL1 and WL2 of the corresponding row and the source line SL. The X driver 3 and the Y driver 4 select the memory cell 2. The memory cell 2 is configured by a magnetoresistance effect element according to an embodiment of the present invention.

[0137] <Twelfth embodiment> 32 is a diagram showing a logic LSI as an integrated circuit according to the twelfth embodiment of the present invention. The logic LSI 6 includes one or more memory units 7, one or more logic units 8, peripheral circuits not shown, and an input / output circuit. At least one of the memory unit 7 and the logic unit 8 includes a magnetoresistive effect element according to the embodiment of the present invention. The logic LSI 6 does not need to have the memory unit 7 and the logic unit 8 arranged in a plane as shown in FIG. 32. For example, the logic LSI 6 may be configured three-dimensionally by arranging a magnetoresistive effect element on the logic unit. [Explanation of symbols]

[0138] 1: Semiconductor memory 6: Logic LSI 10, 10A, 10B, 10C, 10D: Laminated film 11, 11x: first magnetic layer 12,12x: antiferromagnetic coupling layer 12a: Interlayer bonding layer 12b, 12d: Non-magnetic layer (first non-magnetic layer) 12c, 12e: second non-magnetic layer 13, 13x: second magnetic layer 20, 30, 46, 57, 67: Magnetoresistance effect element 22,34,44,55,65:Reference layer 23, 33, 43, 54, 64: Tunnel barrier layer (barrier layer) 24, 32, 42, 53, 63: recording layer 41,52,62: Conductive layer (wiring for SOT-MRAM)

Claims

1. A first magnetic layer; an antiferromagnetic coupling layer adjacent to the first magnetic layer; a second magnetic layer adjacent to the antiferromagnetic coupling layer and antiferromagnetically coupled to the first magnetic layer; Equipped with The antiferromagnetic coupling layer includes a layer containing an Ir--Re alloy, and the atomic percentage of Re in the Ir--Re alloy is greater than 0% and is 12.5% ​​or less.

2. 2. The laminated film according to claim 1, wherein the atomic percentage of Re in said Ir--Re alloy is 10% or less.

3. 2. The laminated film according to claim 1, wherein the atomic percentage of Re in said Ir--Re alloy is 4.5% or less.

4. 2. The laminated film according to claim 1, wherein the layer containing Ir and Re in the antiferromagnetic coupling layer has a thickness greater than 0.2 nm and less than 1.0 nm.

5. 2. The laminated film according to claim 1, wherein at least one of the first magnetic layer and the second magnetic layer comprises a laminate of a Co layer and a Pt layer.

6. 2. The laminated film according to claim 1, wherein the antiferromagnetic coupling layer comprises a layer containing the Ir--Re alloy and a layer containing Pt or an alloy of Pt.

7. 2. The laminated film according to claim 1, wherein the antiferromagnetic coupling layer comprises a layer containing the Ir--Re alloy and a layer containing Ir.

8. A recording layer, a barrier layer, and a reference layer are provided, the recording layer and the reference layer sandwich the barrier layer, A magnetoresistance effect element, wherein the reference layer comprises the laminated film according to claim 1 .

9. a conductive layer, a recording layer, a barrier layer, and a reference layer; The conductive layer comprises the laminated film according to any one of claims 1 to 7, A magnetoresistive element in which the direction of magnetization in the recording layer is reversed by a write current flowing through the conductive layer.

10. A semiconductor memory comprising the magnetoresistive element according to claim 8.

11. A logic LSI comprising the magnetoresistive element according to claim 8.

12. A semiconductor memory comprising the magnetoresistive element according to claim 9.

13. A logic LSI comprising the magnetoresistive element according to claim 9.

Images