JP7095490B2 - Spin-orbit torque type magnetization rotating element, spin-orbit torque type magnetoresistive effect element and magnetic memory - Google Patents

Description

The present invention relates to a spin-orbit torque type magnetization rotating element, a spin-orbit torque type magnetoresistive effect element, and a magnetic memory.

A giant magnetoresistive (GMR) element consisting of a multilayer film of a ferromagnetic layer and a non-magnetic layer, and a tunnel magnetoresistive (TMR) element using an insulating layer (tunnel barrier layer, barrier layer) as the non-magnetic layer have a magnetoresistive effect. Known as an element. In general, a TMR element has a higher element resistance and a larger magnetoresistive (MR) ratio than a GMR element. Therefore, the TMR element is attracting attention as an element for a magnetic sensor, a high frequency component, a magnetic head, and a non-volatile random access memory (MRAM).

The MRAM reads and writes data by utilizing the characteristic that the element resistance of the TMR element changes when the direction of mutual magnetization of the two ferromagnetic layers sandwiching the insulating layer changes. As a writing method of MRAM, a method of writing (magnetization inversion) using a magnetic field created by a current or a method of writing (magnetization) using a spin transfer torque (STT) generated by passing a current in the stacking direction of a magnetoresistive element. A method of performing inversion) is known.

Although the magnetization reversal of the TMR element using STT is efficient from the viewpoint of energy efficiency, it is necessary to pass a current in the laminating direction of the magnetoresistive element when writing data. The write current may deteriorate the characteristics of the magnetoresistive element.

Therefore, in recent years, attention has been focused on magnetization reversal using a pure spin current generated by spin-orbit interaction, which performs magnetization reversal by a mechanism different from that of STT (for example, Patent Document 1). Spin-orbit torque (SOT) is induced by the pure spin current generated by spin-orbit interaction or the Rashba effect at the interface of dissimilar materials. The current for inducing SOT in the magnetoresistive element flows in the direction intersecting the stacking direction of the magnetoresistive element. That is, it is not necessary to pass a current in the stacking direction of the magnetoresistive element, and it is expected that the life of the magnetoresistive element will be extended.

Japanese Unexamined Patent Publication No. 2017-216286

A magnetized rotating element using SOT (SOT type magnetized rotating element) can be expected to have a long life, but is easily affected by a magnetic field. Therefore, the SOT-type magnetized rotating element is required to strictly limit the magnetic field applied to the magnetized free layer of the magnetized rotating element.

As a source of the magnetic field that affects the SOT-type magnetization rotating element, a magnetic field formed by an inverting current for reversing the magnetization can be considered in addition to the external magnetic field. In the case of the SOT type magnetization rotating element, the inverting current flows in the direction intersecting the laminating direction of the magnetoresistive effect element, so that the magnetic field generated from the inverting current is applied to the magnetoresistive effect element according to the right-handed screw rule. That is, the present inventor has focused on the need to reduce the influence of the inverting current in order to increase the efficiency of the SOT-type magnetization rotating element.

The present invention has been made in view of the above circumstances, and provides a spin-orbit torque type magnetization rotating element, a spin-orbit torque type magnetoresistive element, and a magnetic memory in which the influence from a magnetic field formed by an inverting current is reduced. The purpose is.

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

(1) The spin orbital torque type magnetizing rotating element according to the first aspect has a spin orbital torque wiring extending in the first direction, a first ferromagnetic layer laminated on the spin orbital torque wiring, and a plan view. It includes a first soft magnetic material that at least partially surrounds the first ferromagnetic layer, and a first insulator located between the first soft magnetic material and the first ferromagnetic layer.

(2) In the spin-orbit torque type magnetization rotating element according to the above aspect, the first soft magnetic material may at least partially surround the spin-orbit torque wiring in a plan view.

(3) In the spin-orbit torque type magnetization rotating element according to the above aspect, the first soft magnetic material may be made of ferrite.

(4) The spin-orbit torque type magnetization rotating element according to the above aspect includes a second soft magnetic material that at least partially surrounds the first soft magnetic material, the second soft magnetic material, and the first soft magnetic material in a plan view. A second insulator located between the body and the body may be further provided.

(5) The spin-orbit torque type magnetization rotating element according to the above aspect may have a plurality of the first ferromagnetic layers, and the first soft magnetic material is provided over the adjacent first ferromagnetic layers. It may have been magnetized.

(6) The spin-orbit torque type magnetization rotating element according to the above aspect may have a plurality of the first ferromagnetic layers, and the first soft magnetic material is separated into each of the plurality of first ferromagnetic layers. It may be provided.

(7) The spin orbital torque type magnetic resistance effect element according to the second aspect faces the spin orbital torque type magnetized rotating element according to the above aspect and the first ferromagnetic layer on the opposite side to the spin orbital torque wiring. A second ferromagnetic layer is provided, and a non-magnetic layer located between the first ferromagnetic layer and the second ferromagnetic layer is provided.

(8) The magnetic memory according to the third aspect includes a plurality of spin-orbit torque type magnetoresistive elements according to the above aspect.

It is possible to provide a spin orbital torque type magnetization rotating element, a spin orbital torque type magnetoresistive sensor, and a magnetic memory in which the influence from the magnetic field formed by the inverting current is reduced.

It is sectional drawing of the spin-orbit torque type magnetoresistive element which concerns on 1st Embodiment. It is sectional drawing of the spin-orbit torque type magnetoresistive element which concerns on 1st Embodiment manufactured in the manufacturing example 2. FIG. It is sectional drawing of the spin-orbit torque type magnetoresistive element which concerns on 1st Embodiment manufactured in the manufacturing example 3. FIG. It is sectional drawing of the spin-orbit torque type magnetoresistive element which concerns on 1st Embodiment manufactured in the manufacturing example 4. FIG. It is sectional drawing of another example of the spin-orbit torque type magnetoresistive element which concerns on 1st Embodiment. It is a plane schematic diagram of another example of the spin-orbit torque type magnetoresistive element which concerns on 1st Embodiment. It is a plane schematic diagram of another example of the spin-orbit torque type magnetoresistive element which concerns on 1st Embodiment. It is sectional drawing of the spin-orbit torque type magnetizing rotation element which concerns on 2nd Embodiment. It is a figure which shows schematically the magnetic memory which concerns on 3rd Embodiment.

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

"First embodiment"
FIG. 1 is a schematic cross-sectional view of the spin-orbit torque (SOT) type magnetoresistive element 100 according to the first embodiment in the yz plane (FIG. 1 (a)) and the xz plane (FIG. 1 (b)). The SOT-type magnetic resistance effect element 100 according to the first embodiment has a first ferromagnetic layer 1, a spin trajectory torque wiring 2, a non-magnetic layer 3, a second ferromagnetic layer 4, and a first strength in a plan view. It has a first soft magnetic material 121 that at least partially surrounds the magnetic layer 1, and a first insulator 111 that is located between the first soft magnetic material 121 and the first ferromagnetic layer 1. The laminated body in which the first ferromagnetic layer 1, the non-magnetic layer 3 and the second ferromagnetic layer 4 are laminated forms the functional portion 10. In the functional unit 10, the resistance value changes due to the difference in the relative angle between the magnetization of the first ferromagnetic layer 1 and the magnetization of the second ferromagnetic layer 4.

Hereinafter, the first direction in which the spin-orbit torque wiring 2 extends is in the x-direction, and the direction orthogonal to the first direction in the plane in which the spin-orbit torque wiring 2 exists is in the y-direction, the x-direction, or the y-direction. Will be described by defining the direction orthogonal to the z direction. In FIG. 1, the z direction coincides with the stacking direction of the first ferromagnetic layer 1 and the thickness direction of the spin-orbit torque wiring 2.

<First ferromagnetic layer>
The first ferromagnetic layer 1 is laminated on the spin-orbit torque wiring 2. The first ferromagnetic layer 1 functions by changing the direction of its magnetization. In FIG. 1, the first ferromagnetic layer 1 may be a vertical magnetization film in which the magnetization is oriented in the z direction, or an in-plane magnetization film in which the magnetization is oriented in the xy in-plane direction.

A ferromagnetic material, particularly a soft magnetic material, can be applied to the first ferromagnetic layer 1. For example, a metal selected from the group consisting of Cr, Mn, Co, Fe and Ni, an alloy containing one or more of these metals, these metals and at least one or more elements of B, C and N are contained. It is possible to use an alloy or the like. Specifically, Co—Fe, Co—Fe—B, and Ni—Fe can be exemplified. When the first ferromagnetic layer 1 is an in-plane magnetizing film, it is preferable to use, for example, a Co—Ho alloy (CoHo ₂ ), a Sm—Fe alloy (SmFe ₁₂ ), or the like.

The material constituting the first ferromagnetic layer 1 may be a Whistler alloy. The Whisler alloy is a half metal and has a high spin polarizability. The Whisler alloy contains an intermetallic compound with a chemical composition of XYZ or X ₂ YZ, where X is a Co, Fe, Ni or Cu group transition metal element or noble metal element on the periodic table, where Y is Mn. , V, Cr or Ti group transition metal or elemental species of X, Z is a typical element of groups III to V. For example, Co ₂ FeSi, Co ₂ FeGe, Co ₂ FeGa, Co ₂ MnSi, Co ₂ Mn _1-a Fe _a Al _b Si _1-b , Co ₂ FeGe _1-c Ga _c and the like can be mentioned.

<Spin-orbit torque wiring>
The spin-orbit torque wiring 2 extends in the x direction. The spin-orbit torque wiring 2 is connected to the first ferromagnetic layer 1. The spin-orbit torque wiring 2 may be directly connected to the first ferromagnetic layer 1 or may be connected via another layer.

The spin-orbit torque wiring 2 is made of a material in which a spin current is generated by the spin Hall effect when a current flows. As such a material, a material having a configuration in which a spin current is generated in the spin-orbit torque wiring 2 is sufficient. Therefore, the material is not limited to a single element, and may be a portion composed of a material that easily generates a spin current and a portion composed of a material that does not easily generate a spin current. The spin Hall effect is a phenomenon in which a spin current is induced in a direction orthogonal to the direction of the current based on the spin-orbit interaction when a current is passed through the wiring. Hereinafter, the mechanism by which the spin current is generated by the spin Hall effect will be described.

When a potential difference is applied to both ends of the spin-orbit torque wiring 2 in the x direction, a current I flows along the x direction. When the current I flows, the first spin S1 oriented in the y direction and the second spin S2 oriented in the −y direction are bent in the directions orthogonal to the current, respectively. The normal Hall effect and the spin Hall effect are common in that the moving (moving) charge (electron) can bend the moving (moving) direction. However, in the normal Hall effect, charged particles moving in a magnetic field receive Lorentz force and bend the direction of movement, whereas in the spin Hall effect, electrons move only (current flows) even though there is no magnetic field. ), The direction of movement is bent, which is a big difference between the normal Hall effect and the spin Hall effect.

In a non-magnetic material (a material that is not a ferromagnet), the number of electrons in the first spin S1 and the number of electrons in the second spin S2 are equal. Therefore, when the current I is passed in the x direction, the number of electrons in the first spin S1 in the z direction and the number of electrons in the second spin S2 in the −z direction are equal. Therefore, in the z direction, the current as the net flow of charge is zero. This spin current without an electric current is particularly called a pure spin current.

Here, if the electron flow of the first spin S1 is expressed as J _↑ , the electron flow of the second spin S2 is expressed as J _↓ , and the spin flow is expressed as J _S , it is defined as J _S = J _↑ −J _↓ . In FIG. 1, when a current is passed in the x direction, _JS flows in the z direction in the figure as a pure spin current. Here, _JS is a flow of electrons having a polarizability of 100%.

In FIG. 1, when a ferromagnet is brought into contact with the upper surface of the spin-orbit torque wiring 2, the pure spin current diffuses into the ferromagnet and flows into the ferromagnet. That is, spin is injected into the first ferromagnetic layer 1.

The main configuration of the spin-orbit torque wiring 2 is preferably a non-magnetic heavy metal. Here, the heavy metal means a metal having a specific gravity equal to or higher than that of yttrium. The non-magnetic heavy metal is preferably a non-magnetic metal having a d-electron or an f-electron in the outermost shell and having an atomic number of 39 or more and a large atomic number.

Further, the material of the spin-orbit torque wiring 2 is particularly preferably made of a material selected from the group consisting of tungsten, rhenium, osmium, iridium, and an alloy containing at least one of these metals. Tungsten, rhenium, osmium and iridium have 5d electrons in the outermost shell and have a large orbital angular momentum when the five orbitals of the d orbital are degenerate. Therefore, the spin-orbit interaction that causes the spin Hall effect becomes large, and the spin current can be efficiently generated.

Normally, when a current is passed through a metal, all the electrons move in the opposite direction to the current regardless of the direction of their spin, whereas the outermost shell is a non-magnetic metal with a large atomic number and d-electrons or f-electrons. Since the spin orbital interaction is large, the direction of electron movement depends on the direction of the electron spin due to the spin hole effect, and a pure spin current _JS is likely to occur. In particular, when Ir is used as a non-magnetic heavy metal, the spin Hall effect is large. Further, at the interface between Ir and the first ferromagnetic layer 1, a larger vertical magnetic anisotropy than that of the conventional material can be added to the first ferromagnetic layer 1.

Further, the spin-orbit torque wiring 2 may contain a magnetic metal. The magnetic metal refers to a ferromagnetic metal or an antiferromagnetic metal. When the non-magnetic metal contains a small amount of magnetic metal, the spin-orbit interaction is enhanced, and the spin-flow generation efficiency with respect to the current flowing through the spin-orbit torque wiring 2 becomes high. The spin-orbit torque wiring 2 may be made of only antiferromagnetic metal.

The spin-orbit interaction is caused by the inherent internal field of the material of the spin-orbit torque wiring material. Therefore, a spin current is generated even in a non-magnetic material. When a small amount of magnetic metal is added to the spin-orbit torque wiring material, the spin current generation efficiency is improved because the electron spins flowing by the magnetic metal itself are scattered. However, if the amount of the magnetic metal added is too large, the generated spin current is scattered by the added magnetic metal, and as a result, the effect of reducing the spin current becomes stronger. Therefore, it is preferable that the molar ratio of the added magnetic metal is sufficiently smaller than the molar ratio of the main component of the spin generating portion in the spin-orbit torque wiring. As a guide, the molar ratio of the added magnetic metal is preferably 3% or less.

Further, for example, the spin-orbit torque wiring 2 may include a topological insulator. The main component of the spin-orbit torque wiring 2 may be a topological insulator. The topological insulator is a substance in which the inside of the substance is an insulator or a high resistance substance, but a metal state in which spin polarization occurs on the surface thereof. This material has something like an internal magnetic field called spin-orbit interaction. Therefore, a new topological phase appears due to the effect of spin-orbit interaction even in the absence of an external magnetic field. This is a topological insulator, which can generate spin currents with high efficiency due to strong spin-orbit interaction and breaking of inversion symmetry at the edge.

Topological insulators include, for example, SnTe, Bi _1.5 Sb _0.5 Te _1.7 Se _1.3 , TlBiSe ₂ , Bi ₂ Te ₃ , Bi _1-x Sb _x , (Bi _1-x Sb _x ) ₂ . Te ₃ and the like are preferable. These topological insulators can generate spin currents with high efficiency.

<Non-magnetic layer and second ferromagnetic layer>
The SOT-type magnetic resistance effect element 100 according to the first embodiment has a second ferromagnetic layer 4 on the side opposite to the spin track torque wiring 2 of the first ferromagnetic layer 1, and the first ferromagnetic layer 1 and the first. 2 It has a non-magnetic layer 3 between it and the ferromagnetic layer 4.

The laminate (functional unit 10) in which the first ferromagnetic layer 1, the non-magnetic layer 3 and the second ferromagnetic layer 4 are laminated functions in the same manner as a normal magnetoresistive element. The functional unit functions by fixing the magnetization of the second ferromagnetic layer 4 in one direction and changing the direction of the magnetization of the first ferromagnetic layer 1 relatively. When applied to a coercive force difference type (pseudo spin valve type; Pseudo spin valve type) MRAM, the coercive force of the second ferromagnetic layer 4 is made larger than the coercive force of the first ferromagnetic layer 1. When applied to an exchange bias type (spin valve; spin valve type) MRAM, the magnetization of the second ferromagnetic layer 4 is fixed by exchange coupling with the antiferromagnetic layer.

In the functional part, when the non-magnetic layer 3 is made of an insulator, the functional part has the same configuration as a tunnel magnetoresistive (TMR) element, and when the functional part is made of metal, it has a giant magnetoresistance (GMR). : Giant Magnetoresis) The same configuration as the element.

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

A known ferromagnetic material can be used as the material of the second ferromagnetic layer 4. For example, a metal selected from the group consisting of Cr, Mn, Co, Fe and Ni and an alloy containing one or more of these metals and exhibiting ferromagnetism can be used. Alloys containing these metals and at least one or more elements of B, C, and N can also be used. Specific examples thereof include Co-Fe and Co-Fe-B.

The material constituting the second ferromagnetic layer 4 may be a Whistler alloy. The Whisler alloy is a half metal and has a high spin polarizability. The Whisler alloy contains an intermetallic compound with a chemical composition of XYZ or X ₂ YZ, where X is a Co, Fe, Ni or Cu group transition metal element or noble metal element on the periodic table, where Y is Mn. , V, Cr or Ti group transition metal or elemental species of X, where Z is a typical element of groups III to V. For example, Co ₂ FeSi, Co ₂ MnSi, Co ₂ Mn _1-a Fe _a Al _b Si _1-b and the like can be mentioned.

As the laminated structure of the functional unit 10, a known laminated structure of the magnetoresistive element can be adopted. For example, the functional unit may include an antiferromagnetic coupling layer 5 and a magnetization fixing layer 6 for fixing the magnetization direction of the second ferromagnetic layer 4. In this case, the magnetized fixed layer 6 may be made of a ferromagnet, and the second ferromagnetic layer 4, the antiferromagnetic coupling layer 5, and the magnetized fixed layer 6 may form a synthetic antiferromagnetic (SAF) structure. .. In such a SAF structure, the second ferromagnetic layer 4 and the magnetization fixing layer 6 are antiferromagnetic coupled by RKKY interaction via the antiferromagnetic coupling layer 5. As a result, the direction of magnetization of the second ferromagnetic layer 4 and the direction of magnetization of the magnetization fixing layer 6 are antiparallel.

The antiferromagnetic bond layer 5 is a non-magnetic layer, and examples of the material constituting the antiferromagnetic bond layer include Ru, Rh, and Ir, which are non-magnetic metals.

The magnetization fixed layer 6 is made of a ferromagnet. As the material constituting the magnetization fixing layer 6, the same material as the first ferromagnetic layer 1 and the second ferromagnetic layer 4 can be used. For example, the magnetization fixing layer 6 may be composed of Co—Fe—B.

The functional unit 10 may have other layers. For example, the base layer may be provided on the surface of the first ferromagnetic layer 1 opposite to the non-magnetic layer 3, or the cap layer may be provided on the surface of the second ferromagnetic layer 4 opposite to the non-magnetic layer 3. You may have.

The layer disposed between the spin-orbit torque wiring 2 and the first ferromagnetic layer 1 preferably does not dissipate the spin propagating from the spin-orbit torque wiring 2. For example, it is known that silver, copper, magnesium, aluminum and the like have a long spin diffusion length of 100 nm or more, and spin is difficult to dissipate. Further, the thickness of this layer is preferably equal to or less than the spin diffusion length of the substance constituting the layer. When the thickness of the layer is equal to or less than the spin diffusion length, the spin propagating from the spin-orbit torque wiring 2 can be sufficiently transmitted to the first ferromagnetic layer 1.

<First soft magnetic material>
The SOT-type magnetoresistive element 100 according to the first embodiment includes a first soft magnetic material 121 that at least partially surrounds the first ferromagnetic layer 1 in a plan view. "At least partially surrounding the first ferromagnetic layer 1 in a plan view" means a cross section of the first ferromagnetic layer 1 in a plane (xy plane) orthogonal to the stacking direction (z direction) of the first ferromagnetic layer 1. It means that at least a part of the first ferromagnetic layer 1 is contained inside the first soft magnetic material 121. For example, the first soft magnetic material 121 may be arranged so as to sandwich the first ferromagnetic layer 1 in a plan view. In FIGS. 1A and 1B, the first soft magnetic material 121 in the yz cross section and the first soft magnetic material 121 in the xz cross section are one continuous layer. The first soft magnetic material 121 confirmed in each cross section may be a cross section of a different member.

By the first soft magnetic material 121 at least partially surrounding the first ferromagnetic layer 1 in a plan view, the first ferromagnetic layer 1 can be shielded from the surrounding magnetic field. As a result, it is possible to reduce the influence of the magnetic field formed by the inverting current flowing through the spin-orbit torque wiring 2 on the first ferromagnetic layer 1.

It is preferable that the first soft magnetic material 121 completely surrounds the first ferromagnetic layer 1 in a plan view. In this case, the influence of the magnetic field formed by the inverting current flowing through the spin-orbit torque wiring 2 can be further reduced.

Any soft magnetic material can be used as the material constituting the first soft magnetic material 121. For example, Ni—Fe and Co—Fe—Si—B can be used. In particular, it is preferable to use ferrite as the first soft magnetic material 121. By forming the first soft magnetic material 121 with ferrite, the first soft magnetic material 121 can efficiently shield the magnetic field. As a result, the influence of the surrounding magnetic field on the first ferromagnetic layer 1 can be further reduced.

The first soft magnetic material 121 may at least partially surround the spin-orbit torque wiring 2 in a plan view. By the first soft magnetic material 121 at least partially surrounding the spin-orbit torque wiring 2 in a plan view, the influence of the magnetic field formed by the inverting current flowing through the spin-orbit torque wiring 2 on the first ferromagnetic layer 1 is reduced. can do.

The first soft magnetic material 121 may have a sufficient thickness to shield the magnetic field formed by the inverting current flowing through the spin-orbit torque wiring 2. For example, the first soft magnetic material 121 may have a thickness of 0.2 nm to 2.0 μm. The first soft magnetic material 121 may be surrounded by the side wall insulating layer 150 in a plan view. The side wall insulating layer 150 may be formed by using any known insulating material.

<First insulator>
The SOT-type magnetoresistive element 100 according to the first embodiment includes a first insulator 111 located between the first soft magnetic body 121 and the first ferromagnetic body 1. In FIGS. 1A and 1B, the first insulating layer 111 in the yz cross section and the first insulating layer 111 in the xz cross section are one continuous layer. The first insulating layer 111 confirmed in each cross section may be a cross section of a different member. The first insulator 111 electrically insulates the spin-orbit torque wiring 2 and the functional unit 10 from the first soft magnetic body 121. The first insulator 111 may have a sufficient thickness to electrically insulate the spin-orbit torque wiring 2 and the functional portion 10. For example, the first insulator 111 may have a thickness of 0.2 nm to 1.0 μm. As the material of the first insulator 111, any insulating material including oxides and nitrides can be used. For example, Al ₂ O ₃ , SiO ₂ , MgO, MgAl ₂ O ₄ , and the like can be used as the insulating material.

<Upper via and interlayer insulating layer>
The SOT-type magnetoresistive sensor 100 may include an upper via 40. The upper via 40 acts as an electrode for reading and writing data. The upper via 40 comes into contact with the functional portion on the opposite side of the spin-orbit torque wiring 2. However, the upper via 40 is insulated from the first soft magnetic material 121. In plan view, the upper via 40 may be surrounded by the interlayer insulating layer 30. The interlayer insulating layer 30 electrically insulates between the plurality of upper vias 40, and also electrically insulates between the upper vias 40 and the first soft magnetic material 121.

The SOT-type magnetoresistive sensor 100 may have components (not shown in FIG. 1). For example, it may have a substrate or the like as a support. The substrate is preferably excellent in flatness, and for example, Si, AlTiC or the like can be used as the material. Further, an electrode or via wiring for passing a current through the spin-orbit torque wiring 2 may be provided.

<Manufacturing example 1>
An example of a method for manufacturing the SOT-type magnetoresistive element 100 will be described with reference to FIG. First, in order from the spin orbit torque wiring 2 side, a film that will form the spin orbit torque wiring 2, a film that will form the first ferromagnetic layer 1, and a film that will form the non-magnetic layer 3. A laminated film is formed by laminating a film that will form the second ferromagnetic layer 4, a film that will form the antiferromagnetic coupling layer 5, and a film that will form the magnetization fixing layer 6. As a method for laminating each layer, a known method such as a sputtering method or a chemical vapor deposition (CVD) method can be used.

Next, the unnecessary portion of the laminated film is removed by using a technique such as photolithography, and the spin-orbit torque wiring 2, the first ferromagnetic layer 1, the non-magnetic layer 3, the second ferromagnetic layer 4, and the antiferromagnetic coupling layer 5 are removed. , And the magnetization fixed layer 6. After that, the first insulator 111, the first soft magnetic material 121, and the side wall insulating layer 150 are laminated in order so as to cover the processed laminated body.

Next, the spin-orbit torque type magnetoresistive element 100 is obtained by flattening by CMP polishing (chemical mechanical polishing) and exposing the magnetization fixing layer 6. If necessary, the upper via 40 and the interlayer insulating layer 30 are formed. The upper via 40 and the interlayer insulating layer 30 can be manufactured by using any known technique. In this way, the spin-orbit torque type magnetoresistive element 100 of FIG. 1 can be manufactured.

The spin trajectory torque type magnetoresistive sensor 100 according to the first embodiment is a functional unit 10 caused by a difference in the relative angle between the magnetization direction of the first ferromagnetic layer 1 and the magnetization direction of the second ferromagnetic layer 4. Data can be recorded and read by using the resistance value change.

<Manufacturing example 2>
In Production Example 1, the x-direction side portion and the y-direction side portion of the first ferromagnetic layer 1 are first processed, then an insulator is laminated, and then a soft magnetic material is laminated to form a magnetic field shield. did. In Production Example 2, an insulator and a soft magnetic material are first formed on the y-direction side portion of the first ferromagnetic layer 1, and then an insulator and a soft magnetic material are formed on the x-direction side portion of the first ferromagnetic layer 1. The case where the bodies are formed in order will be described. The spin-orbit torque type magnetoresistive element 200 manufactured in this manner is shown in FIG.

Hereinafter, the method for manufacturing the SOT-type magnetoresistive element 200 according to Manufacturing Example 2 will be specifically described with reference to FIG. 2. First, a laminated film is formed in the same manner as in Production Example 1. Next, the unnecessary portion of the side portion in the y-axis direction is removed by using a technique such as photolithography, and the first insulator 111 and the first soft magnetic material are used so that the side portion in the y-axis direction covers the processed laminated film. 121 are stacked in order. Next, the unnecessary portion of the side portion in the x-axis direction is removed by using a technique such as photolithography, and the second insulator 131, the second soft magnetic material 141, and the side wall insulating layer 150 are laminated in order. On the side portion in the y-axis direction, the insulator and the soft magnetic material are laminated twice so as to cover the laminated film. That is, on the yz plane, the first insulating layer 111, the first soft magnetic material 121, the second insulating material 131, and the second soft magnetic layer 141 are laminated in this order.

Next, the spin-orbit torque type magnetoresistive element 200 is obtained by flattening by CMP polishing and exposing the magnetization fixing layer 6. If necessary, the upper via 40 and the interlayer insulating layer 30 are formed. The upper via 40 and the interlayer insulating layer 30 can be manufactured by using any known technique. In this way, the spin-orbit torque type magnetoresistive element 200 of FIG. 2 can be manufactured. In the spin-orbit torque type magnetoresistive element 200 according to the present production example, the second soft magnetic body 141 surrounds the first soft magnetic body 121 at least partially, and the first soft magnetic body 121 and the second soft magnetic body 141 It has a second insulator 131 between the two.

As can be seen from FIG. 2, the SOT-type magnetoresistive element 200 manufactured by Production Example 2 has two layers of soft magnetic material (first soft magnetic material 121 and second) in the y-axis direction of the first ferromagnetic layer 1. It has a soft magnetic material 141). Therefore, the influence of the magnetic field formed by the inverting current flowing through the spin-orbit torque wiring 2 on the first ferromagnetic layer 1 can be effectively reduced.

<Manufacturing example 3>
In Production Example 3, an insulator and a soft magnetic material are first formed on the x-direction side portion of the first ferromagnetic layer 1, and then an insulator and a soft magnetic material are formed on the y-direction side portion of the first ferromagnetic layer 1. The case where the bodies are formed in order will be described. The spin-orbit torque type magnetoresistive element 300 manufactured in this manner is shown in FIG.

Hereinafter, the method for manufacturing the SOT-type magnetoresistive element 300 according to Manufacturing Example 3 will be specifically described with reference to FIG. First, a laminated film is formed in the same manner as in Production Example 1. Next, the unnecessary portion of the side portion in the x-axis direction is removed by using a technique such as photolithography, and the first insulator 111 and the first soft magnetic material are used so that the side portion in the x-axis direction covers the processed laminated film. 121 are stacked in order. Next, the unnecessary portion of the side portion in the y-axis direction is removed by using a technique such as photolithography, and the second insulator 131, the second soft magnetic material 141, and the side wall insulating layer 150 are laminated in order. In the x-axis direction, the insulator and the soft magnetic material are laminated twice so as to cover the laminated film. That is, on the xz plane, the first insulating layer 111, the first soft magnetic material 121, the second insulating material 131, and the second soft magnetic layer 141 are laminated in this order.

Next, the spin-orbit torque type magnetoresistive element 300 is obtained by flattening by CMP polishing and exposing the magnetization fixing layer 6. If necessary, the upper via 40 and the interlayer insulating layer 30 are formed. The upper via 40 and the interlayer insulating layer 30 can be manufactured by using any known technique. In this way, the spin-orbit torque type magnetoresistive element 300 of FIG. 3 can be manufactured. In the spin-orbit torque type magnetoresistive element 300 according to the present production example, the second soft magnetic body 141 surrounds the first soft magnetic body 121 at least partially, and the first soft magnetic body 121 and the second soft magnetic body 141 It has a second insulator 131 between the two.

As can be seen from FIG. 3, the SOT-type magnetoresistive element 300 manufactured by Production Example 3 has two soft magnetic materials (first soft magnetic material 121 and second soft magnetic material 121) in the x direction of the first ferromagnetic layer 1. It has a magnetic material 141). Therefore, the influence of the magnetic field from a similar element arranged around the SOT-type magnetoresistive effect element 300 on the first ferromagnetic layer 1 can be effectively reduced.

In the SOT-type magnetoresistive sensor manufactured in Production Examples 2 and 3, the side surface in the x-axis direction or the side surface in the y-axis direction of the first ferromagnetic layer 1 is doubly surrounded by a soft magnetic material. However, the first ferromagnetic layer 1 may be double-enclosed with a soft magnetic material in both the x-axis direction and the y-axis direction of the first ferromagnetic layer 1, or may be surrounded by three or more layers. Further, the first soft magnetic material 121 and the second soft magnetic material 141 may form arbitrary figures in a plan view. For example, they may be polygons such as circles, ellipses, or quadrangles in plan view.

<Manufacturing example 4>
In Production Example 4, an example in which the line width of the spin-orbit torque wiring 2 is wider than the width of the first ferromagnetic layer 1 will be described. Hereinafter, the method for manufacturing the SOT-type magnetoresistive element 400 according to Manufacturing Example 4 will be specifically described with reference to FIG. First, a laminated film is formed in the same manner as in Production Example 1. Then, unnecessary portions in the x-axis direction and the y-axis direction are removed by using a technique such as photolithography. Here, when processing in the x-axis direction, the spin-orbit torque wiring 2 is not processed, and only the laminated film after the first ferromagnetic layer 1 is processed. Next, the first insulator 111 and the first soft magnetic material 121 are laminated in order so as to cover the processed laminated film. Next, the unnecessary portion in the x-axis direction is removed by using a technique such as photolithography, and the line width of the spin-orbit torque wiring 2 is defined. The second insulator 131, the second soft magnetic material 141, and the side wall insulating layer 150 are laminated in order so as to cover the processed laminated film.

In the SOT-type magnetoresistive sensor 400 manufactured by Production Example 4, the second insulator 131 may be formed of the same material as the first insulator 111, or may be formed of a different material. The second soft magnetic material 141 may be formed of the same material as the first soft magnetic material 121, or may be formed of a different material. Of the first soft magnetic material 121 and the second soft magnetic material 141, it is preferable that at least one is formed of ferrite, and it is more preferable that both are formed of ferrite.

Next, the spin-orbit torque type magnetoresistive element 400 is obtained by flattening by CMP polishing and exposing the magnetization fixing layer 6. If necessary, the upper via 40 and the interlayer insulating layer 30 are formed. The upper via 40 and the interlayer insulating layer 30 can be manufactured by using any known technique. In this way, the spin-orbit torque type magnetoresistive element 400 of FIG. 4 can be manufactured. In the spin-orbit torque type magnetoresistive element 400 according to the present production example, the second soft magnetic body 141 surrounds the first soft magnetic body 121 at least partially, and the first soft magnetic body 121 and the second soft magnetic body 141 It has a second insulator 131 between the two.

As can be seen from FIG. 4, in the SOT-type magnetoresistive element 400 according to Manufacturing Example 4, the line width of the spin-orbit torque wiring 2 is set to an arbitrary line width wider than the width of the first ferromagnetic layer 1. Can be done. By widening the line width of the spin-orbit torque wiring 2, the resistance value of the spin-orbit torque wiring 2 can be lowered. As a result, the energy loss when a current is passed through the spin-orbit torque wiring 2 can be reduced.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments and varies within the scope of the gist of the present invention described in the claims. Can be transformed / changed.

FIG. 5 is a schematic cross-sectional view of another example of the SOT-type magnetoresistive sensor according to the first embodiment. In the SOT-type magnetoresistive element 500 shown in FIG. 5, the point that the first insulator 111 and the first soft magnetic body 121 reach below the substrate 160 supporting the spin-orbit torque wiring 2 is the SOT shown in FIG. It is different from the type magnetoresistive element 100. The SOT-type magnetoresistive element 500 shown in FIG. 5 is manufactured by processing the substrate 160 together when processing the spin-orbit torque wiring 2.

In the SOT-type magnetoresistive element 500 shown in FIG. 5, the first soft magnetic material 121 covers the outer periphery (xy side surface) of the spin-orbit torque wiring 2 over the entire thickness direction (z direction). Therefore, the influence of the magnetic field generated from the spin-orbit torque wiring 2 on other elements can be further suppressed.

Up to this point, the case where one functional unit 10 is provided for one spin-orbit torque wiring 2 has been described as an example, but a plurality of functional units 10 are provided for one spin-orbit torque wiring 2. May be good.

FIG. 6 is a schematic plan view of another example of the SOT-type magnetoresistive sensor according to the first embodiment. The SOT-type magnetization rotating element 600 shown in FIG. 6 has a plurality of functional units 10 on the spin-orbit torque wiring 2. The first soft magnetic material 121 shown in FIG. 6 is provided over a plurality of adjacent functional units 10. In FIG. 6, the first insulating layer 111 is omitted for the sake of simplicity. The first insulating layer 111 is formed along the outer periphery of the functional portion 10. In this case, since the generation of magnetization at the end of the soft magnetic material 121 can be suppressed, the magnetic field can be efficiently shielded.

FIG. 7 is a schematic plan view of another example of the SOT-type magnetoresistive sensor according to the first embodiment. The SOT-type magnetization rotating element 700 shown in FIG. 7 has a plurality of functional units 10 on the spin-orbit torque wiring 2. The first soft magnetic material 121 shown in FIG. 7 is provided separately from each of the plurality of first ferromagnetic layers 1. In this case, even if the soft magnetic material 121 has conductivity, leakage current between the elements can be prevented.

"Second embodiment"
<Spin-orbit torque type magnetization rotating element>
FIG. 8 is a schematic cross-sectional view of the spin-orbit torque type (SOT type) magnetization rotating element 800 according to the second embodiment. The spin orbital torque type magnetization rotating element 800 according to the second embodiment is the non-magnetic layer 3, the second ferromagnetic layer 4, and the antiferromagnetic coupling layer from the SOT type magnetoresistive effect element 100 according to the first embodiment. 5 is a structure excluding the magnetization fixing layer 6, the interlayer insulating layer 30, and the upper via 40. The description of the configuration equivalent to the SOT-type magnetoresistive element of the first embodiment will be omitted.

In the SOT-type magnetization rotating element 800 according to the present embodiment, the first ferromagnetic layer 1 is at least partially surrounded by the first soft magnetic material 121 in a plan view. Therefore, the influence of the magnetic field formed by the inverting current flowing through the spin-orbit torque wiring 2 on the first ferromagnetic layer 1 is reduced.

In the SOT type magnetization rotating element 800 according to the present embodiment, the first soft magnetic material 121 may at least partially surround the spin-orbit torque wiring 2 in a plan view. Thereby, the influence of the magnetic field formed by the inverting current flowing through the spin-orbit torque wiring 2 on the first ferromagnetic layer 1 can be further reduced.

The SOT-type magnetization rotating element 800 according to the present embodiment can be manufactured by the same procedure as the manufacturing example of the SOT-type magnetoresistive element according to the first embodiment. Therefore, the SOT-type magnetizing rotating element is located between the second soft magnetic material, the second soft magnetic material, and the first soft magnetic material 121, which at least partially surrounds the first soft magnetic material 121 in a plan view. 2 Insulator may be further provided.

The SOT-type magnetization rotating element 800 according to the present embodiment can be applied to the above-mentioned SOT-type magnetoresistive effect element. However, the application is not limited to the magnetoresistive effect element, and can be applied to other applications. As another application, for example, it can also be used in a spatial optical modulator in which the above-mentioned SOT type magnetizing rotating element is arranged in each pixel and the incident light is spatially modulated by utilizing the magnetic optical effect. In the magnetic sensor, the magnetic field applied to the easily magnetized axis of the magnet may be replaced with SOT in order to avoid the effect of hysteresis due to the coercive force of the magnet. The SOT-type magnetization rotating element can be particularly referred to as an SOT-type magnetization reversal element when the magnetization is inverted.

"Third embodiment"
<Magnetic memory>
FIG. 9 is a plan view of a magnetic memory 1000 including a plurality of spin-orbit torque type magnetoresistive elements 100 (see FIG. 1). In the magnetic memory 1000 shown in FIG. 9, the spin-orbit torque type magnetoresistive element 100 has a 3 × 3 matrix arrangement. FIG. 9 is an example of the magnetic memory, and the number and arrangement of the spin-orbit torque type magnetoresistive elements 100 are arbitrary.

One word line WL1 to WL3 and one bit line BL1 to BL3 and one lead line RL1 to RL3 are connected to the spin-orbit torque type magnetoresistive element 100, respectively.

By selecting the word lines WL1 to WL3 and the bit lines BL1 to BL3 to which the current is applied, a current is passed through the spin-orbit torque wiring 2 of any spin-orbit torque type magnetoresistive element 100 to perform a writing operation. Further, by selecting the lead lines RL1 to RL3 and the bit lines BL1 to BL3 to which a current is applied, a current is passed in the stacking direction of an arbitrary spin-orbit torque type magnetoresistive element 100 to perform a reading operation. The word lines WL1 to WL3, the bit lines BL1 to BL3, and the lead lines RL1 to RL3 to which the current is applied can be selected by a transistor or the like. That is, it can be used as a magnetic memory by reading data of an arbitrary element from these plurality of spin-orbit torque type magnetoresistive elements 100.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments and varies within the scope of the gist of the present invention described in the claims. Can be transformed / changed.

1 1st ferromagnetic layer 2 Spin orbit torque wiring 3 Non-magnetic layer 4 2nd ferromagnetic layer 5 Anti-ferromagnetic coupling layer 6 Magnetized fixed layer 111 1st insulator 121 1st soft magnetic material 131 2nd insulator 141 2nd Soft magnetic material 150 Side wall insulating layer 30 Interlayer insulating layer 40 Upper via 100, 200, 300, 400, 500, 600, 700 Spin orbit torque type magnetic resistance effect element 800 Spin orbit torque type magnetizing rotating element 1000 Magnetic memory

Claims (7)

Spin-orbit torque wiring extending in the first direction,
The first ferromagnetic layer laminated on the spin-orbit torque wiring and
A first soft magnetic material that at least partially surrounds the first ferromagnetic layer in a plan view,
A first insulator located between the first soft magnetic material and the first ferromagnetic layer is provided.
The first surface of the spin-orbit torque wiring on the first ferromagnetic layer side overlaps the first region overlapping the first ferromagnetic layer when viewed from the stacking direction and the first ferromagnetic layer when viewed from the stacking direction. Has a second region that does not
The first surface in the second region is located at a position away from the first ferromagnetic layer from the first surface in the first region in the stacking direction.
A spin-orbit torque type magnetizing rotating element in which the first soft magnetic material at least partially surrounds the spin-orbit torque wiring in a plan view . The spin-orbit torque type magnetization rotating element according to claim 1 , wherein the first soft magnetic material is made of ferrite. A second soft magnetic material that at least partially surrounds the first soft magnetic material in a plan view,
The spin-orbit torque type magnetization rotating element according to claim 1 or 2 , further comprising a second insulator located between the second soft magnetic material and the first soft magnetic material. Having a plurality of the first ferromagnetic layers,
The spin-orbit torque type magnetization rotating element according to any one of claims 1 to 3 , wherein the first soft magnetic material is provided over an adjacent first ferromagnetic layer. Having a plurality of the first ferromagnetic layers,
The spin-orbit torque type magnetization rotating element according to any one of claims 1 to 4 , wherein the first soft magnetic material is separately provided in each of the plurality of first ferromagnetic layers. The spin-orbit torque type magnetization rotating element according to any one of claims 1 to 5 .
A second ferromagnetic layer facing the first ferromagnetic layer on the opposite side of the spin track torque wiring, and a non-magnetic layer located between the first ferromagnetic layer and the second ferromagnetic layer. A spin orbit torque type magnetic resistance effect element. A magnetic memory provided with a plurality of spin-orbit torque type magnetoresistive elements according to claim 6 .

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