CN112768604A - Tunnel magnetoresistance and manufacturing method thereof - Google Patents

Tunnel magnetoresistance and manufacturing method thereof Download PDF

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Publication number
CN112768604A
CN112768604A CN202011596972.3A CN202011596972A CN112768604A CN 112768604 A CN112768604 A CN 112768604A CN 202011596972 A CN202011596972 A CN 202011596972A CN 112768604 A CN112768604 A CN 112768604A
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layer
pinning
free
field
pinned
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王连伟
何路光
涂恩平
韩荷福
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Bengbu Ximag Technology Co ltd
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Bengbu Ximag Technology Co ltd
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H10N50/10—Magnetoresistive devices
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H10N50/01—Manufacture or treatment
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H10N50/80—Constructional details
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H10N50/80—Constructional details
    • H10N50/85—Magnetic active materials

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Abstract

The invention provides a tunnel magnetoresistance and a preparation method thereof, wherein the tunnel magnetoresistance comprises the following steps: a first pinning layer; a free layer disposed opposite the first pinned layer: a tunneling barrier layer between the first pinned layer and the free layer; a pinned layer between the first pinning layer and the tunneling barrier layer; a second pinning layer on a side of the free layer facing away from the tunneling barrier layer; the first pinning layer and the pinned layer form a first pinning field, the second pinning layer and the free layer form a second pinning field, the directions of the first pinning field and the second pinning field are both parallel to the surface of the first pinning layer opposite to the second pinning layer, and the included angle between the direction of the first pinning field and the direction of the second pinning field is 70-110 degrees. The saturation field of the tunneling magnetoresistance is increased, thereby increasing the linear range of the tunneling magnetoresistance.

Description

Tunnel magnetoresistance and manufacturing method thereof
Technical Field
The invention relates to the technical field of magnetic sensors, in particular to a tunnel magnetoresistance and a manufacturing method thereof.
Background
The magnetic sensing technology is widely applied to the fields of new energy, intelligent transportation, industrial control, intelligent household appliances, intelligent networks and the like. Currently, tmr (tunneling Magneto resistance) technology, i.e. tunneling Magneto resistance, is widely used in the read head portion of hard disk read/write heads.
At present, the linear range of the common tunnel magnetoresistance is narrow, and in order to improve the linear range of the tunnel magnetoresistance, an engineer needs to sputter a hard magnetic material block beside a tunnel magnetoresistance sensing area in the tunnel magnetoresistance processing, and the linear range of the tunnel magnetoresistance is adjusted by using the size of a magnetic field generated by the hard magnetic material block. Or in the application of tunnel magnetoresistance, the linear range of the tunnel magnetoresistance can be adjusted by installing permanent magnets with different magnetic field sizes.
The process of sputtering the hard magnetic material block is added beside the tunnel magnetoresistance sensing area, and although the linear range of the tunnel magnetoresistance can be well improved, the manufacturing cost of the element is additionally increased. In the application of tunnel magnetoresistance, the permanent magnet is installed, and the linear range of tunnel magnetoresistance is improved by utilizing the magnetic field generated by the permanent magnet, but the problems of large installation error of the permanent magnet, poor consistency of products and the like exist.
Disclosure of Invention
Therefore, the present invention is directed to a tunneling magnetoresistance and a method for manufacturing the same, which overcome the problem of the prior art that the linear range of the tunneling magnetoresistance is difficult to be effectively improved.
The invention provides a tunnel magnetoresistance, comprising: a first pinning layer; a free layer disposed opposite the first pinned layer; a tunneling barrier layer between the first pinned layer and the free layer; a pinned layer between the first pinning layer and the tunneling barrier layer; a second pinning layer on a side of the free layer facing away from the tunneling barrier layer; the first pinning layer and the pinned layer form a first pinning field, the second pinning layer and the free layer form a second pinning field, the directions of the first pinning field and the second pinning field are both parallel to the surface of the first pinning layer opposite to the second pinning layer, and the included angle between the direction of the first pinning field and the direction of the second pinning field is 70-110 degrees.
Optionally, a neel temperature of a material of the first pinning layer is greater than a neel temperature of a material of the second pinning layer.
Optionally, the material of the first pinning layer comprises an antiferromagnetic PtMn alloy, and the thickness of the first pinning layer is 15 nm-20 nm.
Optionally, the material of the second pinning layer includes an antiferromagnetic IrMn alloy, and the thickness of the second pinning layer is 7nm to 9 nm.
Optionally, the free layer is a composite structure, and the free layer includes a first free sublayer and a second free sublayer stacked, where the first free sublayer is located between the second free sublayer and the tunneling barrier layer.
Optionally, the free layer further includes: a spacer layer between the first free sublayer and the second free sublayer.
Optionally, the material of the spacer layer includes Ta, and the thickness of the spacer layer is 0.1nm to 0.2 nm.
Optionally, the material of the first free sublayer includes CoFeB, and the thickness of the first free sublayer is 2nm to 2.2 nm; the material of the second free sub-layer comprises NiFe or CoFe, and the thickness of the second free sub-layer is 4 nm-7 nm.
Alternatively, the pinned layer includes a first ferromagnetic layer, a non-ferromagnetic layer, and a second ferromagnetic layer stacked, the first ferromagnetic layer being located between the first pinning layer and the non-ferromagnetic layer.
Optionally, the material of the first ferromagnetic layer includes CoFe, and the thickness of the first ferromagnetic layer is 1.6nm to 2.4 nm; the material of the non-ferromagnetic layer comprises Ru, and the thickness of the non-ferromagnetic layer is 0.7-0.9 nm or 1.8-2 nm; the material of the second ferromagnetic layer comprises CoFeB, and the thickness of the second ferromagnetic layer is 2.4 nm-2.8 nm.
Optionally, the thickness of the first ferromagnetic layer is 2 nm; the thickness of the non-ferromagnetic layer is 0.8nm or 1.9 nm; the second ferromagnetic layer has a thickness of 2.6 nm.
Optionally, the pinned layer further comprises a stabilizing layer of ferromagnetic material on a side of the second pinned layer facing away from the free layer, the stabilizing layer being adapted to increase stability of the second pinning field.
Optionally, the material of the stabilizing layer includes NiFe or CoFe, and the thickness of the stabilizing layer is 4nm to 6 nm.
The invention also provides a preparation method of the tunnel magnetoresistance, which is used for forming the tunnel magnetoresistance, and comprises the following steps: forming a first pinning layer; forming a pinned layer at one side of the first pinning layer; forming a tunneling barrier layer on a side of the pinned layer opposite to the first pinning layer; forming a free layer on a side of the tunneling barrier layer facing away from the pinned layer; forming a second pinning layer on a side of the free layer facing away from the tunneling barrier layer; the first pinning layer and the pinned layer form a first pinning field, the second pinning layer and the free layer form a second pinning field, the directions of the first pinning field and the second pinning field are both parallel to the surface of the first pinning layer opposite to the second pinning layer, and the included angle between the direction of the first pinning field and the direction of the second pinning field is 70-110 degrees.
Optionally, a neel temperature of a material of the first pinning layer is greater than a neel temperature of a material of the second pinning layer; the preparation method of the tunnel magnetoresistance further comprises the following steps: after the second pinning layer is formed, carrying out first annealing magnetization treatment on the first pinning layer, wherein the annealing temperature of the first annealing magnetization treatment is not lower than the neel temperature of the material of the first pinning layer; after the first annealing magnetization, performing a second annealing magnetization on the second pinned layer, wherein the annealing temperature of the second annealing magnetization is lower than the neel temperature of the material of the first pinned layer; and the included angle between the direction of the magnetic field applied by the first annealing magnetization treatment and the direction of the magnetic field applied by the second annealing magnetization treatment is 70-110 degrees, and the included angles are parallel to the surfaces of the first pinning layer and the second pinning layer which are opposite.
Optionally, the method for forming the free layer includes: forming a first free sublayer on a side of the tunneling barrier layer facing away from the first pinned layer; and forming a second free sublayer on the side of the first free sublayer, which faces away from the tunneling barrier layer.
Optionally, the method for forming the free layer further includes: between the step of forming the first free sublayer and the step of forming the second free sublayer, a spacer layer is formed.
The technical scheme of the invention has the following beneficial effects:
1. the invention provides a tunnel magnetoresistance, which comprises: a first pinning layer; a free layer disposed opposite the first pinned layer: a tunneling barrier layer between the first pinned layer and the free layer; a pinned layer between the first pinning layer and the tunneling barrier layer; a second pinning layer on a side of the free layer facing away from the tunneling barrier layer; the first pinning layer and the pinned layer form a first pinning field, the second pinning layer and the free layer form a second pinning field, the directions of the first pinning field and the second pinning field are both parallel to the surface of the first pinning layer opposite to the second pinning layer, and the included angle between the direction of the first pinning field and the direction of the second pinning field is 70-110 degrees. Because the direction of an external magnetic field is parallel to the direction of a pinning field formed by the first pinning layer and the pinned layer when the tunnel magnetoresistance works, the included angle between the pinning field formed by the second pinning layer and the free layer and the direction of the external magnetic field when the tunnel magnetoresistance works is 70-110 degrees, the tunnel magnetoresistance can reach a saturation state only by overcoming the pinning field formed by the additional second pinning layer and the free layer, so that the saturation field of the tunnel magnetoresistance is increased, and the linear range of the tunnel magnetoresistance is enlarged.
2. Further, the neel temperature of the material of the first pinning layer is greater than the neel temperature of the material of the second pinning layer. Therefore, disturbance of the first pinning field can be avoided during magnetization of the second pinning layer, facilitating formation of the second pinning field.
3. Further, a spacer layer is positioned between the first free sublayer and the second free sublayer, and the spacer layer is beneficial to preventing the mutual diffusion between the first free sublayer and the second free sublayer.
4. Further, the material of the second free sub-layer comprises NiFe or CoFe, and the thickness of the second free sub-layer is 4 nm-7 nm. The size of the saturation field of the tunneling magneto-resistance can be adjusted by adjusting the thickness of the second free sublayer, and then the linear range of the tunneling magneto-resistance can be adjusted.
5. Further, the thickness of the first ferromagnetic layer is 2 nm; the thickness of the non-ferromagnetic layer is 0.8nm or 1.9 nm; the thickness of the second ferromagnetic layer was 2.6 nm. Under this condition, the tunneling magnetoresistance has a smaller coercive force.
6. Furthermore, a stabilizing layer made of ferromagnetic materials is arranged on one side, opposite to the free layer, of the second pinning layer, and a pinning field formed by the stabilizing layer and the second pinning layer is favorable for increasing the stability of the magnetic field of the second pinning layer.
7. The invention provides a preparation method of a tunnel magnetoresistance, wherein a second pinning layer is formed on one side of a free layer, which is back to a tunneling barrier layer; the first pinning layer and the pinned layer form a first pinning field, the second pinning layer and the free layer form a second pinning field, the directions of the first pinning field and the second pinning field are both parallel to the surface of the first pinning layer opposite to the second pinning layer, and the included angle between the direction of the first pinning field and the direction of the second pinning field is 70-110 degrees. Because the direction of an external magnetic field is parallel to the direction of a pinning field formed by the first pinning layer and the pinned layer when the tunnel magnetoresistance works, the included angle between the pinning field formed by the second pinning layer and the free layer and the direction of the external magnetic field when the tunnel magnetoresistance works is 70-110 degrees, the tunnel magnetoresistance can reach a saturation state only by overcoming the pinning field formed by the additional second pinning layer and the free layer, so that the saturation field of the tunnel magnetoresistance is increased, and the linear range of the tunnel magnetoresistance is enlarged.
8. Further, a second free sublayer is formed on a side of the first free sublayer facing away from the tunneling barrier layer. The size of the saturation field of the tunneling magneto-resistance can be adjusted by adjusting the thickness of the second free sublayer, and then the linear range of the tunneling magneto-resistance can be adjusted.
9. Further, between the step of forming the first free sublayer and the step of forming the second free sublayer, a spacer layer is formed. The spacer layer advantageously prevents interdiffusion between the first free sublayer and the second free sublayer.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIGS. 1 to 13 are schematic structural diagrams of a tunneling magnetoresistance forming process according to an embodiment of the present invention;
FIG. 13 is a schematic diagram of a tunneling magnetoresistance structure according to an embodiment of the present invention;
FIG. 14 is a top view of a tunneling magnetoresistance according to an embodiment of the invention.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; the two elements may be directly connected or indirectly connected through an intermediate medium, or may be communicated with each other inside the two elements, or may be wirelessly connected or wired connected. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
The embodiment provides a method for preparing a tunnel magnetoresistance, which comprises the following steps: forming a first pinning layer; forming a pinned layer at one side of the first pinning layer; forming a tunneling barrier layer on a side of the pinned layer opposite to the first pinning layer; forming a free layer on a side of the tunneling barrier layer facing away from the pinned layer; forming a second pinning layer on a side of the free layer facing away from the tunneling barrier layer; the first pinning layer and the pinned layer form a first pinning field, the second pinning layer and the free layer form a second pinning field, the directions of the first pinning field and the second pinning field are both parallel to the surface of the first pinning layer opposite to the second pinning layer, and the included angle between the direction of the first pinning field and the direction of the second pinning field is 70-110 degrees.
Fig. 1 to 13 are schematic structural diagrams of a tunneling magnetoresistance forming process according to an embodiment of the present invention.
Referring to fig. 1, a substrate 1 is provided.
The substrate 1 may be a silicon substrate or a glass substrate.
On the surface of one side of the substrate 1Plated with an isolating layer (not shown) made of Al2O3Or SiO2The thickness of the spacer layer is 80nm to 120nm, and may be 80nm, 100nm or 120nm, for example.
Referring to fig. 2, a bottom electrode layer 2 is formed on the surface of the substrate 1 plated with the isolation layer.
The material of the bottom electrode layer 2 is a conductive material, such as: ru, Au or CuN.
Referring to fig. 3, a seed layer 3 is formed on a surface of the bottom electrode layer 2 opposite to the substrate 1.
The seed layer 3 may be a single layer structure composed of Ta or Ru, a double layer structure composed of two layers of Ta and Ru, or a laminated structure composed of Ta and Ru, each layer having a thickness of 5nm to 20nm, for example, 5nm, 10nm, 15nm, or 20 nm.
The seed layer 3 enables the surface roughness of the growth of the first pinning layer 4 to be smaller, is beneficial to the growth of a thin film of the first pinning layer 4, and can also effectively prevent the bottom electrode layer 2, the substrate 1 and the external environment from influencing the tunnel magnetoresistance lattice structure.
Referring to fig. 4, a first pinning layer 4 is formed on a surface of the seed layer 3 on a side facing away from the bottom electrode layer 2.
The material of the first pinned layer 4 comprises an antiferromagnetic PtMn alloy.
The thickness of the first pinning layer 4 is 15nm to 20 nm. For example, it may be 15nm, 17nm, 18nm or 20nm, preferably 17 nm.
Referring to fig. 5, a pinned layer 5 is formed on a surface of the first pinning layer 4 on a side facing away from the seed layer 3.
In the present embodiment, the step of forming the pinned layer 5 includes: forming a first ferromagnetic layer 501 on a surface of the first pinned layer 4 on a side facing away from the seed layer 3; a non-ferromagnetic layer 502 is formed on the surface of the first ferromagnetic layer 501 on the side facing away from the first pinned layer 4; a second ferromagnetic layer 503 is formed on the surface of the non-ferromagnetic layer 502 on the side facing away from the first ferromagnetic layer 501.
In one embodiment, the material of the first ferromagnetic layer 501 comprises CoFe, and the thickness of the first ferromagnetic layer 501 is 1.6nm to 2.4nm, and may be, for example, 1.6nm, 2nm, or 2.4nm, preferably 2 nm. In other embodiments, the first ferromagnetic layer 501 may also be a synthetic antiferromagnetic layer structure formed by sequentially stacking three layers of materials, CoFe, Ru, and CoFe, respectively.
In one embodiment, the material of the non-ferromagnetic layer 502 includes Ru, and the thickness of the non-ferromagnetic layer 502 is 0.7nm to 0.9nm, which may be 0.7nm, 0.8nm, or 0.9nm, for example, and is preferably 0.8 nm. Or 1.8nm to 2nm, for example 1.8nm, 1.9nm or 2nm, preferably 1.9 nm.
In one embodiment, the material of the second ferromagnetic layer 503 includes CoFeB, and the thickness of the second ferromagnetic layer 503 is 2.4nm to 2.8nm, and may be, for example, 2.4nm, 2.6nm, or 2.8nm, and preferably 2.6 nm.
In a preferred embodiment, the tunnel magnetoresistance is lower in coercivity if the first ferromagnetic layer 501 is 2nm thick, the non-ferromagnetic layer 502 is 0.8nm or 1.9nm thick, and the second ferromagnetic layer 503 is 2.6nm thick.
Referring to fig. 6, a tunnel barrier layer 6 is formed on a surface of the pinned layer 5 on a side facing away from the first pinning layer 4.
The material of the tunnel barrier layer 6 includes Al2O3Or MgO.
The tunneling barrier layer 6 has a thickness of 0.5nm to 1.5 nm. For example, it may be 0.5nm, 1nm, 1.2nm or 1.5 nm.
Referring to fig. 7, a first free sublayer 701 is formed on the surface of the tunneling barrier layer 6 on the side facing away from the pinned layer 5.
The material of the first free sublayer 701 includes CoFeB.
The thickness of the first free sublayer 701 is 2nm to 2.2 nm. For example, it may be 2nm, 2.1nm or 2.2 nm.
Referring to fig. 8, a spacer layer 702 is formed on the surface of the first free sublayer 701 opposite to the tunnel barrier layer 6.
The material of the spacer layer 702 includes Ta.
The thickness of the spacer layer 702 is 0.1nm to 0.2 nm. For example, it may be 0.1nm, 0.15nm or 0.2 nm.
The spacer layer 702 is beneficial to prevent the mutual diffusion between the first free sublayer 701 and the second free sublayer 702, if the thickness of the spacer layer 702 is too small, the mutual diffusion between the first free sublayer 701 and the second free sublayer 702 is difficult to prevent, and if the thickness of the spacer layer 702 is too large, the pinning field of the second free sublayer 702 is difficult to penetrate through the spacer layer 702 to pin the first free sublayer 701, so that the free layer 7 cannot be an integral composite structure.
Referring to fig. 9, a second free sublayer 703 is formed on the surface of the spacer layer 702 opposite to the first free sublayer 701.
The material of the second free sublayer 703 comprises NiFe or CoFe.
The thickness of the second free sublayer 703 is 4nm to 7 nm. For example, it may be 4nm, 5nm, 6nm or 7 nm.
In this embodiment, when the thickness of the second free sublayer 703 is 4nm, the saturation field of the second free sublayer 703 is 250 Gs; when the thickness of the second free sublayer 703 is 7nm, the saturation field of the second free sublayer 703 is 160Gs, and the thickness of the second free sublayer 703 can be adjusted as required, so that the size of the saturation field of the tunneling magnetoresistance can be adjusted, and the linear range of the tunneling magnetoresistance can be adjusted.
The free layer in this embodiment is a composite free layer, and the first free sublayer 701, the spacer layer 702, and the second free sublayer 703 are combined to form the free layer 7.
In other embodiments, the free layer is a single layer structure, and the material of the free layer includes CoFeB.
Referring to fig. 10, a second pinned layer 8 is formed on a surface of the free layer 7 on a side opposite to the tunnel barrier layer 6.
The material of the second pinning layer 8 includes IrMn.
The thickness of the second pinning layer 8 is 7nm to 9 nm. For example, it may be 7nm, 8nm or 9nm, preferably 8 nm.
And a second pinning field formed by the second pinning layer 8 and the free layer 7, wherein the direction of the second pinning field is parallel to the surface of the first pinning layer 4 opposite to the second pinning layer 8, the second pinning layer 8 does not pin the free layer 7 completely, so that the direction of the magnetic moment of the free layer 7 can be changed along with the change of the direction of the external magnetic field, and after the external magnetic field is removed, the direction of the magnetic moment of the free layer 7 can be restored to the direction of the initial state.
Referring to fig. 11, a stabilization layer 9 is formed on a surface of the second pinned layer 8 on a side facing away from the free layer 7.
The material of the stabilization layer 9 comprises NiFe or CoFe.
The thickness of the stabilizing layer 9 is 4nm to 6 nm. For example, it may be 4nm, 5nm or 6nm, preferably 5 nm.
The stabilization layer 9 is adapted to increase the stability of the pinning field formed by the second pinned layer 8 and the free layer 7.
In other embodiments, the stabilization layer 9 may not be formed.
Referring to fig. 12, a capping layer 10 is formed on a surface of the stabilization layer 9 on a side facing away from the second pinning layer 8.
The capping layer 10 may have a single-layer structure formed of Ta or Ru, a double-layer structure formed of two layers of Ta and Ru, or a stacked structure formed by sequentially stacking Ta and Ru. Each Ta or Ru layer has a thickness of 5nm to 10nm, and may be, for example, 5nm, 6nm, 8nm or 10 nm.
The cover layer 10 can effectively prevent the tunnel magnetoresistance lattice structure from being influenced by external environment, and the stability of tunnel magnetoresistance is ensured.
Referring to fig. 13, a top electrode layer 11 is formed on the surface of the cap layer 10 opposite to the stabilizer layer 9.
The material of the top electrode layer 11 is a conductive material, such as: ru, Au or CuN.
Next, the first annealing magnetization process is performed on the first pinned layer 4.
The magnetization direction of the first annealing magnetization process is parallel to the surfaces of the first pinned layer 4 and the second pinned layer opposite.
The first annealing magnetization process is along the direction of the X-axis in fig. 14, and in other embodiments, may be along the opposite direction of the X-axis in fig. 14.
The magnitude of the magnetic field of the first annealing magnetization treatment is 8000Gs to 12000Gs, and may be 8000Gs, 10000Gs, or 12000Gs, for example.
The annealing temperature of the first annealing magnetization process is not lower than the neel temperature of the material of the first pinned layer 4. In this embodiment, the material of the first pinning layer 4 is PtMn, the Neel temperature of PtMn is 330 ℃, and the annealing temperature of the first annealing magnetization treatment is 330 ℃ to 350 ℃. For example, it may be 330 ℃, 340 ℃ or 350 ℃. Applying a neel temperature not lower than that of the material of the first pinned layer 4 to the first pinned layer 4 can disturb microscopic magnetic ordering within the material of the first pinned layer 4 so that the magnetic field direction of the first pinned layer 4 is along the magnetization direction.
After the first annealing magnetization process is completed, the first pinning layer 4 and the pinned layer 5 form a first pinning field direction parallel to the surfaces of the first pinning layer 4 and the second pinning layer opposite to each other.
Next, the second annealing magnetization process is performed for the second pinned layer 8.
Referring to fig. 14, fig. 14 is a top view of a tunneling magnetoresistance according to an embodiment of the present invention, and an included angle between an X axis and a Y axis in fig. 14 is 70 ° to 110 °, for example, 70 °, 80 °, 90 °, 100 °, or 110 °, and preferably 90 °. In one embodiment, the direction of the applied magnetic field during tunneling magnetoresistive operation is parallel to the surface of the first pinned layer 4 opposite the second pinned layer 8 and is along the direction of the X-axis in FIG. 14 or along the direction opposite the X-axis in FIG. 14.
With continued reference to FIG. 14, the magnetization direction of the second annealing magnetization is parallel to the surface of the second pinned layer 8 opposite the first pinned layer and along the Y-axis in FIG. 14, and in other embodiments, may be along the opposite direction of the Y-axis in FIG. 14.
The magnitude of the magnetic field of the second annealing magnetization treatment is 200Gs to 400Gs, and may be 200Gs, 300Gs, or 400Gs, for example.
The annealing temperature of the second annealing magnetization process is less than the neel temperature of the material of the first pinned layer 4 and should be avoided to be close to the neel temperature of the material of the first pinned layer 4 in order to avoid the influence on the first pinned layer 4 during the second annealing magnetization process. In this example, the material of the first pinning layer 4 has a neel temperature of 330 ℃, the material of the second pinning layer 8 is IrMn, the neel temperature of IrMn is 270 ℃, and the annealing temperature of the second annealing magnetization process may be 250 ℃ to 280 ℃. For example, it may be 250 ℃, 260 ℃ or 280 ℃. When the annealing temperature of the second annealing magnetization process is lower than the neel temperature of the material of the second pinned layer 8, the microscopic magnetic order in part of the material of the second pinned layer 8 can be disturbed so that the magnetic field direction of the second pinned layer 8 is partially along the magnetization direction, and when the annealing temperature of the second annealing magnetization process is equal to or higher than the neel temperature of the material of the second pinned layer 8, the microscopic magnetic order in all of the material of the second pinned layer 8 can be disturbed so that the magnetic field direction of the second pinned layer 8 is entirely along the magnetization direction.
In this embodiment, the neel temperature of the material of the first pinning layer 4 is greater than the neel temperature of the material of the second pinning layer 8. During the second annealing magnetization process, the annealing temperature of the second annealing magnetization process is less than the neel temperature of the material of the first pinned layer 4. It is possible to avoid disturbing the magnetic field direction of the first pinned layer during magnetization of the second pinned layer 8, facilitating the formation of the magnetic field of the second pinned layer.
And after the second annealing magnetization treatment is finished, a second pinning field is formed by the second pinning layer 8 and the free layer 7, the directions of the first pinning field and the second pinning field are both parallel to the surface of the first pinning layer opposite to the second pinning layer, and the included angle between the direction of the first pinning field and the direction of the second pinning field is 70-110 degrees.
Because the direction of an external magnetic field is parallel to the direction of a pinning field formed by the first pinning layer and the pinned layer when the tunnel magnetoresistance works, the included angle between the pinning field formed by the second pinning layer and the free layer and the direction of the external magnetic field when the tunnel magnetoresistance works is 70-110 degrees, the tunnel magnetoresistance can reach a saturation state only by overcoming the pinning field formed by the additional second pinning layer and the free layer, so that the saturation field of the tunnel magnetoresistance is increased, and the linear range of the tunnel magnetoresistance is enlarged.
The present embodiment provides a tunneling magnetoresistance, please refer to fig. 13, which includes: a first pinning layer 4; a free layer 7 disposed opposite the first pinned layer 4: a tunneling barrier layer 6 between the first pinned layer 4 and the free layer 7; a pinned layer 5 located between the first pinning layer 4 and the tunneling barrier layer 6; a second pinning layer 8 located on a side of the free layer 7 facing away from the tunneling barrier layer 6; the first pinning layer 4 and the pinned layer 5 form a first pinning field, the second pinning layer 8 and the free layer 7 form a second pinning field, the directions of the first pinning field and the second pinning field are both parallel to the surface of the first pinning layer opposite to the second pinning layer, and the included angle between the direction of the first pinning field and the direction of the second pinning field is 70-110 degrees.
The tunneling magnetoresistance further includes a substrate 1, the substrate 1 being located on a side of the first pinning layer 4 facing away from the pinned layer 5.
The substrate 1 may be a silicon substrate or a glass substrate.
An isolation layer (not shown) is plated on the surface of one side of the substrate 1, and the isolation layer is made of Al2O3Or SiO2The thickness of the spacer layer is 80nm to 120nm, and may be 80nm, 100nm or 120nm, for example.
The substrate 1 has a bottom electrode layer 2 on its surface on the side coated with the isolating layer.
The material of the bottom electrode layer 2 is a conductive material, such as: ru, Au or CuN.
On the surface of the bottom electrode layer 2 facing away from the substrate 1, a seed layer 3 is present.
The seed layer 3 may be a single layer structure composed of Ta or Ru, a double layer structure composed of two layers of Ta and Ru, or a laminated structure composed of Ta and Ru, each layer having a thickness of 5nm to 20nm, for example, 5nm, 10nm, 15nm, or 20 nm.
The seed layer 3 enables the surface roughness of the growth of the first pinning layer 4 to be smaller, is beneficial to the growth of a thin film of the first pinning layer 4, and can also effectively prevent the bottom electrode layer 2, the substrate 1 and the external environment from influencing the tunnel magnetoresistance lattice structure.
The material of the first pinned layer 4 comprises an antiferromagnetic PtMn alloy.
The thickness of the first pinning layer 4 is 15nm to 20 nm. For example, it may be 15nm, 16nm, 18nm or 20 nm.
The pinned layer 5 includes a first ferromagnetic layer 501, a non-ferromagnetic layer 502, and a second ferromagnetic layer 503 laminated, the first ferromagnetic layer 501 being located between the first pinning layer 4 and the non-ferromagnetic layer 502.
In one embodiment, the material of the first ferromagnetic layer 501 comprises CoFe, and the thickness of the first ferromagnetic layer 501 is 1.6nm to 2.4nm, and may be, for example, 1.6nm, 2nm, or 2.4nm, preferably 2 nm. In other embodiments, the first ferromagnetic layer 501 may also be a synthetic antiferromagnetic layer structure formed by sequentially stacking three layers of materials, CoFe, Ru, and CoFe, respectively.
In one embodiment, the material of the non-ferromagnetic layer 502 includes Ru, and the thickness of the non-ferromagnetic layer 502 is 0.7nm to 0.9nm, which may be 0.7nm, 0.8nm, or 0.9nm, for example, and is preferably 0.8 nm. Or 1.8nm to 2nm, for example 1.8nm, 1.9nm or 2nm, preferably 1.9 nm.
In one embodiment, the material of the second ferromagnetic layer 503 includes CoFeB, and the thickness of the second ferromagnetic layer 503 is 2.4nm to 2.8nm, and may be, for example, 2.4nm, 2.6nm, or 2.8nm, and preferably 2.6 nm.
In a preferred embodiment, the tunnel magnetoresistance is lower in coercivity if the first ferromagnetic layer 501 is 2nm thick, the non-ferromagnetic layer 502 is 0.8nm or 1.9nm thick, and the second ferromagnetic layer 503 is 2.6nm thick.
The material of the tunnel barrier layer 6 includes Al2O3Or MgO.
The tunneling barrier layer 6 has a thickness of 0.5nm to 1.5 nm. For example, it may be 0.5nm, 1nm, 1.2nm or 1.5 nm.
The free layer 7 is a composite structure, and the free layer 7 includes a first free sublayer 701 and a second free sublayer 703 that are stacked.
The material of the first free sublayer 701 includes CoFeB.
The thickness of the first free sublayer 701 is 2nm to 2.2 nm. For example, it may be 2nm, 2.1nm or 2.2 nm.
The material of the second free sublayer 703 comprises NiFe or CoFe.
The thickness of the second free sublayer 703 is 4nm to 7 nm. For example, it may be 4nm, 5nm, 6nm or 7 nm.
In this embodiment, when the thickness of the second free sublayer 703 is 4nm, the saturation field of the second free sublayer 703 is 250 Gs; when the thickness of the second free sublayer 703 is 7nm, the saturation field of the second free sublayer 703 is 160Gs, and the thickness of the second free sublayer 703 can be adjusted as required, so that the size of the saturation field of the tunneling magnetoresistance can be adjusted, and the linear range of the tunneling magnetoresistance can be adjusted.
The free layer 7 further includes: a spacer layer 702 located between the first free sublayer 701 and the second free sublayer 703.
The material of the spacer layer 702 includes Ta.
The thickness of the spacer layer 702 is 0.1nm to 0.2 nm. For example, it may be 0.1nm, 0.15nm or 0.2 nm.
The free layer in this embodiment is a composite free layer, and the first free sublayer 701, the spacer layer 702, and the second free sublayer 703 are combined to form the free layer 7. The first free sublayer 701 is located between the tunneling barrier layer 6 and the spacer layer 702; the second free sublayer 703 is located between the spacer layer 702 and the second pinned layer 8.
In other embodiments, the free layer is a single layer structure, and the material of the free layer includes CoFeB.
The material of the second pinning layer 8 includes IrMn.
The thickness of the second pinning layer 8 is 7nm to 9 nm. For example, it may be 7nm, 8nm or 9nm, preferably 8 nm.
The tunneling magnetoresistance further comprises: a stabilizing layer 9 of ferromagnetic material located on the side of the second pinned layer 8 facing away from the free layer 7, the stabilizing layer 9 being adapted to increase the stability of the pinning field formed by said second pinned layer and the free layer.
The material of the stabilization layer 9 comprises NiFe or CoFe.
The thickness of the stabilizing layer 9 is 4nm to 6 nm. For example, it may be 4nm, 5nm or 6nm, preferably 5 nm.
In other embodiments, the tunneling magnetoresistance may not include the stabilization layer 9.
There is also a capping layer 10 on the surface of the stabilization layer 9 on the side facing away from the second pinned layer 8.
The capping layer 10 may have a single-layer structure formed of Ta or Ru, a double-layer structure formed of two layers of Ta and Ru, or a stacked structure formed by sequentially stacking Ta and Ru. Each Ta or Ru layer has a thickness of 5nm to 10nm, and may be, for example, 5nm, 6nm, 8nm or 10 nm.
The cover layer 10 can effectively prevent the tunnel magnetoresistance lattice structure from being influenced by external environment, and the stability of tunnel magnetoresistance is ensured.
A top electrode layer 11 is also present on the surface of the cover layer 10 on the side facing away from the stabilizing layer 9.
The material of the top electrode layer 11 is a conductive material, such as: ru, Au or CuN.
Because the direction of an external magnetic field is parallel to the direction of a pinning field formed by the first pinning layer and the pinned layer when the tunnel magnetoresistance works, the included angle between the pinning field formed by the second pinning layer and the free layer and the direction of the external magnetic field when the tunnel magnetoresistance works is 70-110 degrees, the tunnel magnetoresistance can reach a saturation state only by overcoming the pinning field formed by the additional second pinning layer and the free layer, so that the saturation field of the tunnel magnetoresistance is increased, and the linear range of the tunnel magnetoresistance is enlarged.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.

Claims (17)

1. A tunneling magnetoresistance, comprising:
a first pinning layer;
a free layer disposed opposite the first pinned layer;
a tunneling barrier layer between the first pinned layer and the free layer;
a pinned layer between the first pinning layer and the tunneling barrier layer;
a second pinning layer on a side of the free layer facing away from the tunneling barrier layer;
the first pinning layer and the pinned layer form a first pinning field, the second pinning layer and the free layer form a second pinning field, the directions of the first pinning field and the second pinning field are both parallel to the surface of the first pinning layer opposite to the second pinning layer, and the included angle between the direction of the first pinning field and the direction of the second pinning field is 70-110 degrees.
2. The tunneling magnetoresistance of claim 1, wherein the first pinning layer material has a neel temperature greater than the neel temperature of the second pinning layer material.
3. Tunneling magnetoresistance according to claim 1 or 2, characterized in that the material of the first pinning layer comprises an antiferromagnetic PtMn alloy, the thickness of the first pinning layer being between 15nm and 20 nm.
4. Tunneling magnetoresistance according to claim 1 or 2, characterized in that the material of the second pinning layer comprises an antiferromagnetic IrMn alloy, the thickness of the second pinning layer being 7nm to 9 nm.
5. The tunneling magnetoresistance of claim 1, wherein the free layer is a composite structure, the free layer comprises a first free sublayer and a second free sublayer stacked, the first free sublayer being located between the second free sublayer and the tunneling barrier layer.
6. The tunneling magnetoresistance of claim 5, wherein the free layer further comprises: a spacer layer between the first free sublayer and the second free sublayer.
7. Tunneling magnetoresistance according to claim 6, wherein the material of the spacer layer comprises Ta, and the thickness of the spacer layer is 0.1nm to 0.2 nm.
8. The tunneling magnetoresistance of claim 5, wherein the material of the first free sublayer comprises CoFeB, and the thickness of the first free sublayer is 2nm to 2.2 nm; the material of the second free sub-layer comprises NiFe or CoFe, and the thickness of the second free sub-layer is 4 nm-7 nm.
9. The tunneling magnetoresistance of claim 1, wherein the pinned layer comprises a first ferromagnetic layer, a non-ferromagnetic layer, and a second ferromagnetic layer stacked, the first ferromagnetic layer being located between the first pinning layer and the non-ferromagnetic layer.
10. The tunneling magneto-resistor of claim 9, wherein the material of the first ferromagnetic layer comprises CoFe, and the thickness of the first ferromagnetic layer is 1.6nm to 2.4 nm; the material of the non-ferromagnetic layer comprises Ru, and the thickness of the non-ferromagnetic layer is 0.7-0.9 nm or 1.8-2 nm; the material of the second ferromagnetic layer comprises CoFeB, and the thickness of the second ferromagnetic layer is 2.4 nm-2.8 nm.
11. The tunneling magnetoresistance of claim 10, wherein the first ferromagnetic layer has a thickness of 2 nm; the thickness of the non-ferromagnetic layer is 0.8nm or 1.9 nm; the second ferromagnetic layer has a thickness of 2.6 nm.
12. The tunneling magneto-resistor of claim 1, further comprising: a stabilizing layer of ferromagnetic material on a side of the second pinned layer opposite the free layer, the stabilizing layer adapted to increase stability of the second pinning field.
13. Tunneling magnetoresistance according to claim 12, wherein the material of the stabilizer layer comprises NiFe or CoFe, and the thickness of the stabilizer layer is 4nm to 6 nm.
14. A method of manufacturing a tunneling magnetoresistance for forming the tunneling magnetoresistance of any of claims 1 to 13, comprising the steps of:
forming a first pinning layer;
forming a pinned layer at one side of the first pinning layer;
forming a tunneling barrier layer on a side of the pinned layer opposite to the first pinning layer;
forming a free layer on a side of the tunneling barrier layer facing away from the pinned layer;
forming a second pinning layer on a side of the free layer facing away from the tunneling barrier layer;
the first pinning layer and the pinned layer form a first pinning field, the second pinning layer and the free layer form a second pinning field, the directions of the first pinning field and the second pinning field are both parallel to the surface of the first pinning layer opposite to the second pinning layer, and the included angle between the direction of the first pinning field and the direction of the second pinning field is 70-110 degrees.
15. The method of claim 14, wherein the first pinning layer material has a neel temperature greater than the neel temperature of the second pinning layer material;
the preparation method of the tunnel magnetoresistance further comprises the following steps: after the second pinning layer is formed, carrying out first annealing magnetization treatment on the first pinning layer, wherein the annealing temperature of the first annealing magnetization treatment is not lower than the neel temperature of the material of the first pinning layer; after the first annealing magnetization, performing a second annealing magnetization on the second pinned layer, wherein the annealing temperature of the second annealing magnetization is lower than the neel temperature of the material of the first pinned layer;
and the included angle between the direction of the magnetic field applied by the first annealing magnetization treatment and the direction of the magnetic field applied by the second annealing magnetization treatment is 70-110 degrees, and the included angles are parallel to the surfaces of the first pinning layer and the second pinning layer which are opposite.
16. The method of claim 14, wherein the method of forming the free layer comprises: forming a first free sublayer on a side of the tunneling barrier layer facing away from the first pinned layer; and forming a second free sublayer on the side of the first free sublayer, which faces away from the tunneling barrier layer.
17. The method of claim 16, wherein the method of forming the free layer further comprises: between the step of forming the first free sublayer and the step of forming the second free sublayer, a spacer layer is formed.
CN202011596972.3A 2020-12-28 2020-12-28 Tunnel magnetoresistance and manufacturing method thereof Pending CN112768604A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115148896A (en) * 2022-06-10 2022-10-04 珠海多创科技有限公司 Magnetic sensor, preparation method thereof and electronic equipment

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115148896A (en) * 2022-06-10 2022-10-04 珠海多创科技有限公司 Magnetic sensor, preparation method thereof and electronic equipment

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