Tunnel magnetoresistive sensor based on Wheatstone full-bridge structure and manufacturing method thereof

Abstract

The invention provides a tunnel magnetoresistive sensor based on a Wheatstone full-bridge structure and a manufacturing method thereof, and the tunnel magnetoresistive sensor comprises two tunnel magnetoresistive unit structures which comprise heavy metal layers; two magnetic tunnel junctions are deposited on the heavy metal layer; the antiferromagnetic layer is deposited on the surface of the reference layer of the magnetic tunnel junction so as to fix the pinning direction of the magnetic tunnel junction; the pinning directions of the four magnetic tunnel junctions in the two tunnel magnetic resistance unit structures are the same, the four magnetic tunnel junctions are connected according to a Wheatstone full-bridge structure, currents in different directions are introduced into the heavy metal layer, the magnetization directions of the free layers in the magnetic tunnel junctions are biased through the spin-orbit moment effect, and the magnetic resistance of the magnetic tunnel junctions is improved. The magnetization directions of the free layers in two adjacent magnetic tunnel junctions are symmetrical about the X axis in the XY plane. The magnetoresistive sensor is high in sensitivity and wide in linear interval, the spin orbit moment is used instead of the process bias magnetization direction, the machining process is simplified, errors generated by different processes are eliminated, and the accuracy of magnetic field measurement is improved.

Description

Technical Field

[0001] The invention belongs to the field of magnetoresistive sensors, and in particular relates to a tunnel magnetoresistive sensor based on a Wheatstone full-bridge structure and a manufacturing method thereof. Background Art

[0002] Spintronics is a field that uses the properties of electron spin, where spin torque is an efficient current-controlled magnetism technology. It is widely used in magnetic storage, but has not received much attention in another application, magnetoresistive sensors. Magnetoresistive (MR) sensors have high sensitivity and robustness. Sensors based on intrinsic anisotropic magnetoresistive (AMR) of 3d ferromagnets, giant magnetoresistive (GMR) of spin valve multilayer structures, and tunneling magnetoresistive (TMR) of magnetic tunnel junctions are gradually replacing semiconductor-based Hall effect sensors and are used in various IoT applications. High-performance MR sensors need to have a large linear operating range, small hysteresis, and high signal-to-noise ratio. Compared with other magnetoresistive sensors, TMR has a higher output signal, a larger linear operating range, and low hysteresis at the expense of sensitivity.

[0003] In traditional TMR sensors, two pairs of magnetic tunnel junctions are required, which are pinned in different biasing directions through different processing techniques. However, errors will occur between different processes. Therefore, reducing or eliminating errors is a key challenge for magnetoresistive sensors in precise magnetic field measurement applications. Summary of the invention

[0004] In view of the above shortcomings of the prior art, the purpose of the present invention is to provide a tunnel magnetoresistive sensor based on a Wheatstone full-bridge structure and a manufacturing method thereof, so as to solve the problem that in the existing traditional TMR sensor, two pairs of magnetic tunnel junctions with pinning directions offset by different processing techniques are required, and errors will occur between different processes.

[0005] To achieve the above-mentioned object and other related objects, the present invention proposes a tunnel magnetoresistive sensor based on a Wheatstone full-bridge structure, comprising:

[0006] Two tunnel magnetoresistance unit structures, the tunnel magnetoresistance unit structure comprising:

[0007] Heavy metal layer;

[0008] A magnetic tunnel junction, two magnetic tunnel junctions are deposited on the heavy metal layer;

[0009] An antiferromagnetic layer, wherein the antiferromagnetic layer is deposited on the reference layer surface of the magnetic tunnel junction to fix the pinning reverse direction of the magnetic tunnel junction;

[0010] Among them, the pinning directions of the four magnetic tunnel junctions in the two tunnel magnetoresistive unit structures are the same and are connected according to a Wheatstone full-bridge structure. Currents in different directions are passed through the heavy metal layer, and the magnetization direction of the free layer in the magnetic tunnel junction is biased by the spin-orbit torque effect. The magnetization direction of the free layer in the two adjacent magnetic tunnel junctions is symmetrical about the X-axis in the XY plane.

[0011] In a preferred embodiment of the present invention, the width of the heavy metal layer is greater than the width of the magnetic tunnel junction, and the length of the heavy metal layer is greater than twice the length of the magnetic tunnel junction.

[0012] In a preferred embodiment of the present invention, the magnetic tunnel junction also includes a barrier layer, the free layer is deposited on the surface of the heavy metal layer, and the barrier layer is located between the reference layer and the free layer, wherein the material of the reference layer and the free layer is CoFeB or NiFe, and the material of the barrier layer is MgO.

[0013] In a preferred embodiment of the present invention, the thickness of the reference layer and the free layer is set between 1.9 nm and 4 nm, and the thickness of the barrier layer is set between 1 nm and 1.8 nm.

[0014] In a preferred embodiment of the present invention, the heavy metal layer, the free layer, the barrier layer, the reference layer and the antiferromagnetic layer are all multi-layer deposition structures.

[0015] In a preferred embodiment of the present invention, the antiferromagnetic layer is a three-layer structure, and the thickness of each layer is respectively set between 8nm and 20nm, between 2nm and 3nm, and between 0.65nm and 0.85nm.

[0016] In a preferred embodiment of the present invention, the thickness of the heavy metal layer is set between 3 nm and 10 nm.

[0017] In a preferred embodiment of the present invention, the aspect ratio of the magnetic tunnel junction is set in a range of 2 to 10.

[0018] In a preferred embodiment of the present invention, the length of the magnetic tunnel junction is set to be between 40 μm and 500 μm, and the width is set to be between 10 μm and 100 μm.

[0019] The present invention also proposes a method for manufacturing a tunnel magnetoresistive sensor based on a Wheatstone full-bridge structure, comprising:

[0020] Depositing a thin film on a substrate to form an initial structure, the initial structure comprising a heavy metal layer, an initial free layer, an initial barrier layer, an initial reference layer and an initial antiferromagnetic layer;

[0021] Annealing the initial structure formed by deposition;

[0022] Etching the initial structure after annealing to remove part of the initial free layer, the initial barrier layer, the initial reference layer and the initial antiferromagnetic layer to form two magnetic tunnel junctions, wherein the two magnetic tunnel junctions and the heavy metal layer form a tunnel magnetoresistive unit structure;

[0023] The two tunnel magnetoresistive unit structures are connected so that four magnetic tunnel junctions form a Wheatstone full bridge structure.

[0024] The present invention proposes a tunnel magnetoresistive sensor based on a Wheatstone full-bridge structure and a manufacturing method thereof, two tunnel magnetoresistive unit structures, each tunnel magnetoresistive unit structure includes a heavy metal layer and two magnetic tunnel junctions thereon, and a total of four magnetic tunnel junctions are connected according to the Wheatstone full-bridge structure. In the Wheatstone bridge structure, the heavy metal layer passes through different current directions, and the spin-orbit torque generated by the heavy metal layer biases different free layer magnetization directions, thereby differentially obtaining a linear output voltage. The antiferromagnetic layer stacked on the reference layer will fix the pinning direction of the reference layer, so that the pinning directions of the four magnetic tunnel junctions are the same. This arrangement method fully electrically completes signal linearization, modulation and other operations, greatly simplifies the device structure and reduces the difficulty of manufacturing.

[0025] The magnetoresistive sensor obtained by the present invention has a large sensitivity and a wide linear range. By using the spin-orbit moment instead of the process bias magnetization direction, the processing technology is simplified, while the errors caused by different processes are eliminated, thereby improving the accuracy of measuring the magnetic field. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0027] Figure 1 A diagram showing the Wheatstone bridge structure of a spin torque biased magnetoresistive sensor;

[0028] Figure 2 Shown in the figure above is the magnetic field analysis of MTJ1 and MTJ2 under different spin-orbit moment bias magnetization directions and a schematic diagram of the magnetization direction.

[0029] Figure 3 It is shown as a graph of linear range, sensitivity and current density, where Figure 3 (a) shows the relationship between the linear interval and the current density; Figure 3 (b) shows the relationship between sensitivity and current density;

[0030] Figure 4 It is shown as a linear interval, a graph of the relationship between the current density and the spin-orbit moment damping-like term or field-like term; where, Figure 4 (a) shows the relationship between the linear interval, current density and the damping-like term; Figure 4 (b) shows the relationship between sensitivity, current density and field-like terms;

[0031] Figure 5 It is shown as a relationship diagram between size parameters, sensitivity and linear range, where: Figure 5 (a) shows the relationship between sensitivity, linear range and aspect ratio at different fixed lengths or widths; Figure 5 (b) shows the relationship between sensitivity, linear range and width at a fixed aspect ratio. DETAILED DESCRIPTION

[0032] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0033] It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner. Therefore, the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0034] See also Figure 1 and Figure 2As shown, in this embodiment, the purpose of the present invention is to provide a tunnel magnetoresistive sensor based on a Wheatstone full-bridge structure and a manufacturing method thereof, so as to solve the problem that in the existing traditional TMR sensor, two pairs of magnetic tunnel junctions with biased pinning directions through different processing techniques are required, and errors will occur between different processes. The tunnel magnetoresistive sensor 100 includes two tunnel magnetoresistive unit structures 10, each tunnel magnetoresistive unit structure 10 includes a heavy metal layer 11, two magnetic tunnel junctions 12 and an antiferromagnetic layer (not shown), the two magnetic tunnel junctions 12 are deposited on the surface of the heavy metal layer 11, the magnetic tunnel junctions 12 include a reference layer 121, a barrier layer 122 and a free layer 123, the free layer 123 is deposited on the surface of the heavy metal layer 11, the barrier layer 122 is located between the reference layer 121 and the free layer 123, the antiferromagnetic layer is deposited on the surface of the reference layer 121 of the magnetic tunnel junction 12, and the four magnetic tunnel junctions 12 in the two tunnel magnetoresistive unit structures 10 have the same pinning direction and are connected in a Wheatstone full bridge structure.

[0035] See also Figure 1 and Figure 2 As shown, Figure 1 A Wheatstone bridge structure diagram of a spin torque biased magnetoresistive sensor is shown. Figure 2 The magnetic field analysis and magnetization direction of MTJ1 (magnetic tunnel junction 1) and MTJ2 (magnetic tunnel junction 2) under different spin-orbit moment bias magnetization directions are shown in the figure above. The magnetization direction of the free layer is determined by the anisotropy field H. k , demagnetization field H dx and H dy , external magnetic field H y And the spin-orbit moment equivalent field H SOT Joint influence, through different H SOT Different free layer magnetization directions m can be biased free In this embodiment, the pinning direction of the magnetic tunnel junction 12 is fixed by the antiferromagnetic layer, and the pinning directions m of the four magnetic tunnel junctions 12 in the two tunnel magnetoresistive unit structures 10 are pinSimilarly, currents in different directions are passed through the heavy metal layer 11, and the magnetization direction of the free layer 123 in the magnetic tunnel junction 12 is biased by the spin-orbit torque effect. The magnetization directions of the free layers in two adjacent magnetic tunnel junctions 12 are symmetrical about the X-axis in the XY plane. Four magnetic tunnel junctions 12 are connected in a full-bridge structure to form a differential circuit to improve sensitivity and linearity. Currents in different directions are passed through the heavy metal layer, and the magnetization direction of the free layer 123 is biased by the spin-orbit moment effect. The magnetization direction of the free layer 123 of the four magnetic tunnel junctions 12 is biased to different directions by the spin-orbit moment. When the external magnetic field acts, the resistance of the four magnetic tunnel junctions 12 changes differently. Through differential amplification, a linear output voltage is obtained. Compared with the traditional method, two pairs of magnetic tunnel junctions that are biased in the pinning direction by different processing techniques are required, which leads to the problem of errors between different processes. The arrangement method in this application fully electrically completes signal linearization, modulation and other operations, greatly simplifies the device structure, reduces the difficulty of manufacturing, uses spin-orbit moment instead of process bias magnetization direction, simplifies the processing technology, and eliminates the errors caused by different processes, thereby improving the accuracy of measuring the magnetic field. It can be understood that the XY plane in this article is the plane formed along the width direction and length direction of the heavy metal layer, the X axis is an axis along the length direction, and the Y axis is an axis along the width direction.

[0036] See also Figure 1 As shown, in this embodiment, the width W of the heavy metal layer 11 is greater than the width W of the magnetic tunnel junction 12, and the length L of the heavy metal layer 11 is greater than twice the length L of the magnetic tunnel junction 12. A larger heavy metal layer can improve the distribution of current in the magnetic tunnel junction area, reduce local overheating or current concentration, thereby improving the stability and reliability of the device, and at the same time increase the efficiency of spin accumulation and spin injection, thereby more effectively controlling the magnetization direction of the magnetic tunnel junction.

[0037] See also Figure 1 As shown, in this embodiment, the heavy metal layer 11, the free layer 123, the barrier layer 122, the reference layer 121 and the antiferromagnetic layer are all multi-layer deposition structures. The multi-layer structure can enhance the magnetization stability of the free layer 123 and the reference layer 121, and reduce the energy required for magnetization switching. The multi-layer barrier structure can optimize the barrier layer thickness, material composition and interface quality, thereby enhancing the electron tunneling effect and improving the tunneling magnetoresistance ratio. The optimized barrier layer can reduce defects and leakage in the electron tunneling process and improve the energy efficiency of the device. The multi-layer antiferromagnetic structure can more effectively control the magnetization direction of the reference layer to ensure its stability under zero field. The multi-layer deposition structure can disperse thermal stress and mechanical stress, reduce interlayer delamination or cracks caused by temperature changes or external pressure, and optimize the material combination and deposition process of each layer to improve the stability of the device in high temperature, high humidity or other harsh environments.

[0038] See also Figure 1 As shown, in this embodiment, the thickness t of the reference layer 121 and the free layer 123 is set between 1.9nm and 4nm. The thinner reference layer 121 and the free layer 123 can reduce the energy required for magnetization switching, thereby improving the efficiency of the spin-orbit torque. In the thickness range of 1.9nm to 4nm, the magnetization direction of the reference layer and the free layer can be more stable, reducing the magnetization switching caused by thermal fluctuations. The appropriate thickness can ensure that the magnetic anisotropy of the magnetic layer is moderate, neither too high to cause switching difficulties nor too low to cause stability reduction. In this embodiment, the material of the reference layer 121 and the free layer 123 is CoFeB or NiFe, preferably CoFeB.

[0039] The thickness t of the barrier layer 122 is set between 1 nm and 1.8 nm, which can effectively control the electron tunneling effect, thereby improving the tunneling magnetoresistance ratio. A thinner barrier layer can reduce the leakage of electrons during the tunneling process, reduce the energy consumption of the device, and can also amplify the tunneling current change caused by magnetic reversal, thereby improving the sensitivity of the read signal. In this embodiment, the material of the barrier layer is MgO.

[0040] The antiferromagnetic layer is a three-layered structure, and the thickness t of each layer is set between 8nm and 20nm, between 2nm and 3nm, and between 0.65nm and 0.85nm, respectively. Through the layered design, the first layer is thicker, and the exchange bias of the antiferromagnetic layer can better resist the interference of the external magnetic field, increase the exchange bias strength, and ensure the stability of the magnetization direction of the reference layer. The second layer can optimize the interface coupling and enhance the magnetic coupling between the antiferromagnetic layer and the reference layer. The third layer provides fine thickness control, further enhances the exchange bias effect, and the three-layer structure can disperse thermal stress, avoid local overheating, and improve the overall thermal stability of the device. In this embodiment, the three-layer materials of the antiferromagnetic layer are PtMn, CoFe, Ru or IrMn, CoFe, Ru.

[0041] The thickness t of the heavy metal layer 11 is set between 3nm and 10nm. The thickness of the heavy metal layer directly affects the strength of the spin-orbit coupling effect. The range of 3nm to 10nm can ensure the best performance of the spin-orbit torque effect, control the distribution of current between the free layer and the reference layer, reduce local overheating and current concentration, and by optimizing the thickness, reduce the energy required for current injection and reduce the power consumption of the device. In this embodiment, the material of the heavy metal layer 11 is Pt, Ta or W, preferably Ta.

[0042] See also Figure 1As shown, in the present embodiment, the aspect ratio of the magnetic tunnel junction 12 is set in the range of 2 to 10. For example, the length range of the magnetic tunnel junction 12 is set in the range of 40 μm to 500 μm, and the width range is set in the range of 10 μm to 100 μm, so that it can better disperse thermal stress, reduce magnetization reversal or structural failure caused by temperature changes, reduce the formation of local hot spots, and improve the thermal stability of the device; the distribution of current in the magnetic tunnel junction 12 can be optimized, and the phenomenon of current concentration in a certain area can be reduced, which helps to reduce the risk of local overheating and current leakage, thereby improving the energy efficiency and reliability of the device, and can also improve the sensitivity and linear range of the magnetic sensor, and can ensure the consistency between different MTJs, thereby providing the overall performance of the device.

[0043] It is understandable that, in this embodiment, it is necessary to perform sensitivity and linear range verification calculation on the tunnel magnetoresistive sensor 100, for example, Figure 3 (a) shows the linear range (H WR ) and current density (J e ), in the derivation of the analytical solution, it is assumed that the third term of the Taylor expansion of the trigonometric approximation should be less than k times the sum of the first two terms. Figure 3 (a) Comparison of the linear range analytical curves for different coefficients k and the numerical curves obtained by the simulation model shows that the linear range gradually decreases with the increase of current density; Figure 3 (b) shows the sensitivity (SEN) and current density (J e ), Figure 3 (b) shows the comparison between the sensitivity analytical curve and the numerical curve obtained by the simulation model. It can be seen that with the increase of current density, its sensitivity gradually increases. Figure 3 (a) and Figure 3 (b), the intersection of the normalized numerical solution curve can be taken as the optimal working point. Figure 4 (a) shows the linear interval, current density and damping-like term (H DL ), such as Figure 4 (b) Displayed as sensitivity, current density and field-like term (H FL ), it can be seen that the spin-orbit moment bias magnetization direction is mainly affected by the field-like term. Figure 5 (a) shows the relationship between sensitivity, linear range and aspect ratio at different fixed lengths or widths, such as Figure 5 (b) shows the relationship between sensitivity, linear range and width at a fixed aspect ratio. It can be seen that the demagnetization field size is affected by increasing the aspect ratio and increasing the size, thereby sacrificing a certain linear range to obtain higher sensitivity. Based on the above analysis, the parameters of the tunnel magnetoresistive sensor 100 in this application can be optimized.

[0044] See also Figure 1 As shown, in this embodiment, the present invention further proposes a method for manufacturing a tunnel magnetoresistive sensor based on a Wheatstone full-bridge structure, comprising:

[0045] Thin film deposition is performed on a substrate to form an initial structure, the initial structure including a heavy metal layer, an initial free layer, an initial barrier layer, an initial reference layer and an initial antiferromagnetic layer; for example, a heavy metal layer is deposited on the substrate, an initial free layer is deposited on the heavy metal layer, an initial barrier layer is deposited on the free layer, an initial reference layer is deposited on the barrier layer, and an initial antiferromagnetic layer is deposited on the reference layer.

[0046] The initial structure formed by deposition is subjected to annealing treatment; it should be noted that, before the annealing treatment, the deposited initial structure needs to be cleaned to remove pollutants and oxides on the surface.

[0047] The initial structure after annealing is etched to remove part of the initial free layer, the initial barrier layer, the initial reference layer and the initial antiferromagnetic layer to form two magnetic tunnel junctions, and the two magnetic tunnel junctions and the heavy metal layer constitute a tunnel magnetoresistive unit structure; for example, a mask is formed on the initial structure after annealing using photolithography technology to define the shape and position of the two magnetic tunnel junctions, and the initial free layer, the initial barrier layer, the initial reference layer and the initial antiferromagnetic layer outside the mask are removed using dry etching or wet etching, the photolithography mask is removed, and the etched sample is cleaned to ensure that the surface is clean and free of residue.

[0048] The two tunnel magnetoresistive unit structures are connected so that the four magnetic tunnel junctions form a Wheatstone full-bridge structure. For example, the electrodes of the two tunnel magnetoresistive unit structures are connected using a conductive material to form a Wheatstone full-bridge structure.

[0049] The present invention proposes a tunnel magnetoresistive sensor based on a Wheatstone full-bridge structure and a manufacturing method thereof, two tunnel magnetoresistive unit structures, each tunnel magnetoresistive unit structure includes a heavy metal layer and two magnetic tunnel junctions thereon, and a total of four magnetic tunnel junctions are connected according to the Wheatstone full-bridge structure. In the Wheatstone bridge structure, the heavy metal layer passes through different current directions, and the spin-orbit torque generated by the heavy metal layer biases different free layer magnetization directions, thereby differentially obtaining a linear output voltage. The antiferromagnetic layer stacked on the reference layer will fix the pinning direction of the reference layer, so that the pinning directions of the four magnetic tunnel junctions are the same. This arrangement method fully electrically completes signal linearization, modulation and other operations, greatly simplifies the device structure and reduces the difficulty of manufacturing.

[0050] The magnetoresistive sensor obtained by the present invention has a large sensitivity and a wide linear range. Through the spin-orbit torque (SOT) bias technology, only one thin film deposition and one annealing treatment are required, which simplifies the processing technology, eliminates the errors caused by different processes, and improves the accuracy of measuring the magnetic field.

[0051] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

[0052] In the description herein, many specific details, such as examples of components and / or methods, are provided to provide a complete understanding of embodiments of the present invention. However, those skilled in the art will recognize that embodiments of the present invention may be practiced without one or more of the specific details or with other devices, systems, components, methods, components, materials, parts, etc. In other cases, well-known structures, materials, or operations are not specifically shown or described in detail to avoid obscuring aspects of embodiments of the present invention.

[0053] References throughout this specification to "one embodiment," "an embodiment," or "a specific embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention, and not necessarily in all embodiments. Thus, various appearances of the phrases "in one embodiment," "in an embodiment," or "in a specific embodiment" in different places throughout this specification do not necessarily refer to the same embodiment. In addition, the particular features, structures, or characteristics of any specific embodiment of the invention may be combined with one or more other embodiments in any suitable manner. It should be understood that other variations and modifications of the embodiments of the invention described and illustrated herein may be possible in light of the teachings herein and are to be considered part of the spirit and scope of the invention.

[0054] It should also be understood that one or more of the elements shown in the figures may also be implemented in a more separate or more integrated manner, or even removed because they are inoperable in certain circumstances or provided because they may be useful depending on the application.

[0055] In addition, unless otherwise explicitly indicated, any marking arrows in the drawings should be regarded as exemplary only and not limiting. In addition, unless otherwise indicated, the term "or" used herein is generally intended to mean "and / or". In the case where the term is not clear because it is anticipated that the ability to separate or combine is provided, the combination of components or steps will also be regarded as indicated.

[0056] As used in the description herein and throughout the claims that follow, "a," "an," and "the" include plural references unless otherwise indicated. Likewise, as used in the description herein and throughout the claims that follow, the meaning of "in" includes "in" and "on," unless otherwise indicated.

[0057] The above description of the illustrated embodiments of the present invention (including the contents described in the Abstract) is not intended to be an exhaustive list or to limit the present invention to the precise form disclosed herein. Although specific embodiments of the present invention and examples of the present invention are described herein for illustrative purposes only, various equivalent modifications are possible within the spirit and scope of the present invention as will be recognized and appreciated by those skilled in the art. As noted, these modifications may be made to the present invention in accordance with the above description of the embodiments described in the present invention, and these modifications will be within the spirit and scope of the present invention.

[0058] Systems and methods have been generally described herein as details that aid in understanding the present invention. In addition, various specific details have been given to provide an overall understanding of embodiments of the present invention. However, those skilled in the relevant art will recognize that embodiments of the present invention may be practiced without one or more of the specific details, or may be practiced using other devices, systems, accessories, methods, components, materials, parts, etc. In other cases, well-known structures, materials, and / or operations are not specifically shown or described in detail to avoid confusion with various aspects of embodiments of the present invention.

[0059] Thus, although the invention has been described herein with reference to specific embodiments thereof, freedom of modification, various changes and substitutions are also within the foregoing disclosure, and it should be understood that in some cases, some features of the invention will be employed without the corresponding use of other features without departing from the scope and spirit of the proposed invention. Thus, many modifications may be made to adapt a particular environment or material to the essential scope and spirit of the invention. The invention is not intended to be limited to the specific terms used in the claims below and / or the specific embodiments disclosed as the best mode contemplated for carrying out the invention, but the invention will include any and all embodiments and equivalents falling within the scope of the appended claims. Thus, the scope of the invention will be determined solely by the appended claims.

Claims

1. A tunnel magnetoresistive sensor based on a Wheatstone full-bridge structure, characterized in that: include: Two tunnel magnetoresistance unit structures, the tunnel magnetoresistance unit structure comprising: Heavy metal layer; A magnetic tunnel junction, two magnetic tunnel junctions are deposited on the heavy metal layer; an antiferromagnetic layer, wherein the antiferromagnetic layer is deposited on a surface of a reference layer of the magnetic tunnel junction to fix a pinning direction of the magnetic tunnel junction; Among them, the pinning directions of the four magnetic tunnel junctions in the two tunnel magnetoresistive unit structures are the same and are connected according to a Wheatstone full-bridge structure. Currents in different directions are passed through the heavy metal layer, and the magnetization direction of the free layer in the magnetic tunnel junction is biased by the spin-orbit torque effect. The magnetization direction of the free layer in the two adjacent magnetic tunnel junctions is symmetrical about the X-axis in the XY plane.

2. The tunnel magnetoresistive sensor based on the Wheatstone full bridge structure according to claim 1, characterized in that: The width of the heavy metal layer is greater than the width of the magnetic tunnel junction, and the length of the heavy metal layer is greater than twice the length of the magnetic tunnel junction.

3. The tunnel magnetoresistive sensor based on the Wheatstone full bridge structure according to claim 1, characterized in that: The magnetic tunnel junction also includes a barrier layer, the free layer is deposited on the surface of the heavy metal layer, and the barrier layer is located between the reference layer and the free layer, wherein the reference layer and the free layer are made of CoFeB or NiFe, and the barrier layer is made of MgO.

4. The tunnel magnetoresistive sensor based on the Wheatstone full bridge structure according to claim 3, characterized in that: The thickness of the reference layer and the free layer is set between 1.9 nm and 4 nm, and the thickness of the barrier layer is set between 1 nm and 1.8 nm.

5. The tunnel magnetoresistive sensor based on the Wheatstone full bridge structure according to claim 3, characterized in that: The heavy metal layer, the free layer, the barrier layer, the reference layer and the antiferromagnetic layer are all multi-layer deposition structures.

6. The tunnel magnetoresistive sensor based on the Wheatstone full bridge structure according to claim 1, characterized in that: The antiferromagnetic layer is a three-layer structure, and the thickness of each layer is respectively set between 8nm and 20nm, between 2nm and 3nm, and between 0.65nm and 0.85nm.

7. The tunnel magnetoresistive sensor based on the Wheatstone full bridge structure according to claim 1, characterized in that: The thickness of the heavy metal layer is set between 3nm and 10nm.

8. The tunnel magnetoresistive sensor based on the Wheatstone full bridge structure according to claim 1, characterized in that: The aspect ratio of the magnetic tunnel junction is set in a range of 2 to 10.

9. The tunnel magnetoresistive sensor based on the Wheatstone full bridge structure according to claim 8, characterized in that: The length of the magnetic tunnel junction is set to be between 40 μm and 500 μm, and the width is set to be between 10 μm and 100 μm.

10. A method for manufacturing a tunnel magnetoresistive sensor based on a Wheatstone full-bridge structure, characterized in that: include: Depositing a thin film on a substrate to form an initial structure, the initial structure comprising a heavy metal layer, an initial free layer, an initial barrier layer, an initial reference layer and an initial antiferromagnetic layer; Annealing the initial structure formed by deposition; Etching the initial structure after annealing to remove part of the initial free layer, the initial barrier layer, the initial reference layer and the initial antiferromagnetic layer to form two magnetic tunnel junctions, wherein the two magnetic tunnel junctions and the heavy metal layer form a tunnel magnetoresistive unit structure; The two tunnel magnetoresistive unit structures are connected so that four magnetic tunnel junctions form a Wheatstone full bridge structure.

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