Wide-range closed-loop TMR current sensor based on interlayer exchange coupling

Abstract

The invention relates to the technical field of current detection, in particular to a wide-range closed-loop TMR current sensor based on interlayer exchange coupling. Comprising a substrate, a buffer layer, a vertical magnetic anisotropy thin film, an oxide tunneling layer, an in-plane magnetic anisotropy thin film and a protective layer which are sequentially arranged from bottom to top, the substrate is a silicon substrate wafer, and SiO2 is oxidized on the surface of the substrate to improve the adhesiveness of an electronic thin film and the surface roughness of the wafer; the buffer layer is made of non-magnetic metal and is used for improving the surface roughness of a wafer and improving the performance of a magnetic film; the perpendicular magnetic anisotropy thin film is of an artificially synthesized antiferromagnetic structure designed based on the interlayer exchange coupling effect. The TMR effect formed between the perpendicular magnetic anisotropy thin film and the in-plane magnetic anisotropy thin film and the designed artificially synthesized antiferromagnetic structure are utilized, so that the current detection range of the current sensor is remarkably enlarged.

Description

Technical Field

[0001] The invention relates to the technical field of current detection, and in particular to a wide-range closed-loop TMR current sensor based on interlayer exchange coupling. Background Art

[0002] With the continuous development of electronic and electrical equipment, current sensors, as key components for detecting current signals, are increasingly used in more and more scenarios. The market's requirements for the frequency band, accuracy, measurement range, and response speed of current detection are also increasing. At present, the mainstream current sensing technology types on the market mainly include shunt resistance measurement, current transformer, Rogowski coil, Hall current sensor, and magnetoresistive current sensor.

[0003] Although the shunt resistance measurement method has a simple structure, it cannot achieve electrical isolation. It needs to shut down the power supply and disconnect the busbar during disassembly and assembly, and the measurement accuracy is easily affected by the ambient temperature. The current transformer based on the transformer principle is easy to use and has the advantage of electrical insulation. However, it is only suitable for time-varying current measurement, has a large size, high cost, narrow measurement frequency band, and is susceptible to electromagnetic interference. The Rogowski coil has the advantages of small size, light weight, and low price, but it is also only suitable for time-varying current measurement, has low measurement accuracy, and is difficult to achieve mass production.

[0004] Hall and magnetoresistive current sensors detect current by sensing the size of the magnetic field generated by a current-carrying conductor. They have the advantages of electrical isolation, small size, light weight, wide bandwidth, and fast response speed. In recent years, their share in the field of miniature intelligent current sensors has gradually increased. According to different technical development routes, Hall and magnetoresistive current sensors can be further divided into open-loop and closed-loop current sensors.

[0005] The open-loop current sensor directly senses the magnetic field generated by the current in a long straight conductor to measure the current. The output of the magnetic probe chip is linearly related to the magnitude of the sensed magnetic field, so the current value in the conductor can be detected by the magnitude of the sensor output value.

[0006] The closed-loop current sensor adds a feedback loop consisting of an operational amplifier, a transistor, and a compensation coil. The output signal of the magnetic probe chip is amplified by the operational amplifier and drives the transistor. The output current of the transistor generates a magnetic field in the compensation coil that is opposite to the magnetic field generated by the energized wire. When the magnetic fields generated by the two are equal in magnitude, the compensation current reaches a stable value, and the magnetic probe chip is in a zero magnetic flux environment. According to the output voltage or current of the sensor, the current in the energized wire can be converted.

[0007] Compared with open-loop current sensors, closed-loop current sensors have the advantages of good output linearity, high accuracy, wide bandwidth, large dynamic range, high loop gain and good stability. The AMR (anisotropic magnetoresistance), GMR (giant magnetoresistance) and TMR (tunnel magnetoresistance) elements in the magnetic probe chip have the advantages of high sensitivity, low power consumption, small size and good linearity. However, their magnetic sensitivity direction is usually in the plane, and the current detection range is narrow (the linear output range is usually within 0~200Gs). When applied, they can only detect the magnetic field parallel to their surface. In order to improve the application performance of the closed-loop current sensor during design, the air gap of the magnetic core needs to be as small as possible, which requires the direction of the magnetic field generated by the magnetic core structure to be perpendicular to the surface of the magnetic probe chip. Therefore, AMR, GMR and TMR elements cannot be directly matched with closed-loop current sensors.

[0008] Although the magnetic sensitivity direction of the Hall element is out of the plane and can match the direction of the magnetic field generated by the closed-loop structure, it has disadvantages such as poor temperature characteristics, low sensitivity, and high power consumption, which is also not conducive to the high-performance application of current sensors.

[0009] In summary, the existing current sensing technology still has certain deficiencies in terms of matching with closed-loop current sensors, current detection range, stability, sensitivity and accuracy. Summary of the invention

[0010] The present invention provides a wide-range closed-loop TMR current sensor based on interlayer exchange coupling, which aims to improve the matching performance, current detection range, stability, sensitivity and accuracy of the existing current sensing technology and the closed-loop current sensor.

[0011] To achieve the above object, the technical solution of the present invention is:

[0012] A wide-range closed-loop TMR current sensor based on interlayer exchange coupling comprises a substrate, a buffer layer, a perpendicular magnetic anisotropic film, an oxide tunneling layer, an in-plane magnetic anisotropic film and a protective layer arranged in sequence from bottom to top, wherein:

[0013] The substrate is a silicon wafer with SiO2 oxidized on its surface. 2 To improve electronic film adhesion and wafer surface roughness;

[0014] The buffer layer is a non-magnetic metal and is used to improve the surface roughness of the wafer and enhance the performance of the magnetic film;

[0015] The perpendicular magnetic anisotropic film is an artificial synthetic antiferromagnetic structure designed based on interlayer exchange coupling, including a plurality of perpendicular magnetic anisotropic film layers that form antiferromagnetic coupling and ferromagnetic coupling through a non-magnetic layer;

[0016] The oxide tunneling layer is made of MgO having a spin electron filtering effect;

[0017] The in-plane magnetic anisotropic film is made of CoFeB with a high spin polarization rate, and its thickness is set to achieve in-plane magnetic anisotropy while obtaining a magnetoresistance change rate of 50% to 150%;

[0018] The protective layer is used to protect the magnetic film from being oxidized and contaminated by the external environment.

[0019] Furthermore, the artificial antiferromagnetic structure of the perpendicular magnetic anisotropic film is specifically: [first perpendicular magnetic anisotropic film] / non-magnetic Ru layer / [second perpendicular magnetic anisotropic film] / non-magnetic W layer / [third perpendicular magnetic anisotropic film-CoFeB], wherein the first and second perpendicular magnetic anisotropic films form antiferromagnetic coupling through the non-magnetic Ru layer, and the second and third perpendicular magnetic anisotropic films form ferromagnetic coupling through the non-magnetic W layer.

[0020] Furthermore, the first and second perpendicular magnetic anisotropic films adopt a film structure of [Pt / CoFeB]n, [Pd / CoFeB]n, [Co / Pt]n or [Co / Pd]n, wherein n is the number of periods, and these film structures obtain perpendicular magnetic anisotropy through orbital hybridization.

[0021] Furthermore, by adjusting the period numbers of the first and second perpendicular magnetic anisotropic films, the magnetic moment orientation of the third perpendicular magnetic anisotropic film CoFeB can be changed, thereby realizing the differential output structure design of the Wheatstone bridge.

[0022] Furthermore, the thickness of the in-plane magnetic anisotropic film CoFeB is 1.8-3 nm to obtain a magnetoresistance change rate of 50%-150% and increase device sensitivity.

[0023] Furthermore, the thickness of the out-of-plane magnetic anisotropic film CoFeB is 0.8~1.4nm, which can be orbitally hybridized with MgO to overcome the demagnetization field to obtain perpendicular magnetic anisotropy. As the thickness increases, the magnetization direction of CoFeB will gradually change from out-of-plane magnetic anisotropy to in-plane magnetic anisotropy.

[0024] Furthermore, the material of the protective layer includes Ta, Pt, and AlOx.

[0025] Furthermore, the SiO2 oxidized on the surface of the substrate 2 The thickness is 300~500nm.

[0026] The beneficial effects achieved by the present invention are:

[0027] The invention discloses a wide-range closed-loop TMR current sensor based on interlayer exchange coupling, which significantly increases the current detection range of the current sensor by utilizing the TMR effect formed between the perpendicular magnetic anisotropic film and the in-plane magnetic anisotropic film and the designed artificial synthetic antiferromagnetic structure. In particular, by adjusting the thickness of the in-plane magnetic anisotropic film CoFeB layer, the linear output range of the sensor can be further widened to achieve wide-range current detection.

[0028] The invention discloses a wide-range closed-loop TMR current sensor based on interlayer exchange coupling. The TMR element in the scheme has high sensitivity and can accurately respond to small magnetic field changes. At the same time, by optimizing the film structure and preparation process, a large magnetoresistance change rate can be obtained, thereby further improving the measurement accuracy of the current sensor.

[0029] The invention discloses a wide-range closed-loop TMR current sensor based on interlayer exchange coupling. The design of the closed-loop current sensor places the magnetic probe chip in a zero-flux environment, effectively reducing external magnetic field interference and improving the stability of the sensor. In addition, the use of high-quality thin film materials and advanced preparation technology ensures the long-term reliability and adaptability of the sensor to harsh environments.

[0030] The invention discloses a wide-range closed-loop TMR current sensor based on interlayer exchange coupling, which has low power consumption and is conducive to energy saving and consumption reduction. At the same time, by simplifying the structure and optimizing the preparation process, the production cost can be reduced and the market competitiveness can be improved.

[0031] The invention discloses a wide-range closed-loop TMR current sensor based on interlayer exchange coupling, which is suitable for high-precision measurement of AC and DC current signals in the fields of ground vehicles, ships, aircraft, weapons, aerospace, etc. In particular, in the occasions requiring high-performance current detection, such as electric vehicles, smart grids, aerospace, etc., the solution has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0033] Figure 1 It is a schematic diagram of the structure of the closed-loop current sensor system of the present invention.

[0034] Figure 2Schematic diagram of the overall film structure of the TMR probe chip in the present invention, wherein 1 is a substrate; 2 is a buffer layer; 3 is a perpendicular magnetic anisotropic film; 4 is an oxide tunneling layer; 5 is an in-plane magnetic anisotropic film; and 6 is a protective layer.

[0035] Figure 3 Schematic diagram of the structure of the artificial antiferromagnetic film in the present invention, in which 11 is a buffer layer - Ta; 21 is a first perpendicular magnetic anisotropic film; 31 is a non-magnetic isolation layer Ru; 41 is a second perpendicular magnetic anisotropic film; 51 is a non-magnetic isolation layer W; 61 is a third perpendicular magnetic anisotropic film - CoFeB.

[0036] Figure 4 It is a schematic diagram of the relationship between the magnetic moment orientation of each layer of the perpendicular magnetic anisotropic film in the artificial synthetic antiferromagnetic film structure of the present invention and the change of the external magnetic field.

[0037] Figure 5 It is a schematic diagram of the Wheatstone bridge structure principle in the present invention.

[0038] Figure 6 It is a schematic diagram of the relationship between the output of the Wheatstone bridge in the present invention and the change of the external magnetic field.

[0039] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0042] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if the meaning of "and / or" appearing in the full text is to include three parallel schemes, taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0043] like Figures 1 to 6 As shown, the present invention provides a design method for a closed-loop current sensor with high sensitivity and wide current detection range based on a TMR element, wherein the output value of the closed-loop TMR current sensor is linearly output as the magnitude of the out-of-plane magnetic field changes by using the magnetic moment orientation between the perpendicular magnetic anisotropic film and the in-plane magnetic anisotropic film arranged at 90 degrees, that is, the magnetic sensitivity direction of the TMR element is matched with the air gap structure of the closed-loop current sensor. The present invention has a simple structure, higher sensitivity, better thermal stability and lower power consumption than the closed-loop Hall current sensor, and higher accuracy, better temperature characteristics and stronger anti-interference ability than the open-loop AMR, GMR and TMR current sensors. At the same time, the perpendicular magnetic anisotropic film with a large exchange bias field and the in-plane magnetic anisotropic film with a large out-of-plane saturation field designed by the present invention using the interlayer exchange coupling effect can further broaden the current detection range of the closed-loop TMR current sensor, making its application range wider.

[0044] A wide-range closed-loop TMR current sensor based on interlayer exchange coupling, the specific structure of which includes a substrate, a buffer layer, a perpendicular magnetic anisotropic film, an oxide tunneling layer, an in-plane magnetic anisotropic film and a protective layer from bottom to top, such as Figure 2 shown.

[0045] The substrate is a conventional silicon wafer, and 300-500 nm SiO is oxidized on Si. 2 To improve the adhesion of electronic films, wafer surface roughness and other properties.

[0046] The buffer layer includes non-magnetic metals such as Ta, Ru, Pt, and W. The buffer layer is an electronic film between the wafer and the magnetic functional layer. On the one hand, it can improve the surface roughness of the wafer and enhance the performance of the magnetic film. On the other hand, it is beneficial to enhance the magnetoresistance change rate of the magnetic film to obtain higher device sensitivity.

[0047] The perpendicular magnetic anisotropic film is an artificial synthetic antiferromagnetic structure designed based on interlayer exchange coupling: [first perpendicular magnetic anisotropic film] / non-magnetic Ru layer / [second perpendicular magnetic anisotropic film] / non-magnetic W layer / [third perpendicular magnetic anisotropic film-CoFeB], wherein the first and second perpendicular magnetic anisotropic films form antiferromagnetic coupling through the non-magnetic Ru layer, and the second and third perpendicular magnetic anisotropic films form ferromagnetic coupling through the non-magnetic W layer. This film structure is conducive to generating a large exchange bias field to broaden the current detection range of the current sensor, such as Figure 3 The first and second perpendicular magnetic anisotropic films usually adopt a film structure of [Pt / CoFeB] n or [Pd / CoFeB] n or [Co / Pt] n or [Co / Pd] n etc. These thin film structures can obtain perpendicular magnetic anisotropy through orbital hybridization.

[0048] The oxide tunneling layer is usually made of MgO which has a spin electron filtering effect.

[0049] The in-plane magnetic anisotropic film usually uses CoFeB with a high spin polarization rate. When the thickness of CoFeB is relatively thin (0.8~1.4nm), it can be orbitally hybridized with MgO to overcome the demagnetization field to obtain perpendicular magnetic anisotropy. As the thickness increases, the magnetization direction of CoFeB will gradually change from out-of-plane magnetic anisotropy to in-plane magnetic anisotropy. The in-plane magnetic anisotropic film in the TMR element often uses 1.8~3nm CoFeB (the out-of-plane saturation field is usually 2000~6000Gs), which is conducive to obtaining a magnetoresistance change rate of 50%~150% to increase the sensitivity of the device.

[0050] The protective layer is usually made of Ta, Pt, AlO x And other thin film materials to protect the magnetic film from being oxidized and polluted by the external environment.

[0051] The design method of the wide-range closed-loop TMR current sensor is as follows:

[0052] In the structure of perpendicular magnetic anisotropy artificial antiferromagnetic film, the magnetic moment orientation of the third perpendicular magnetic anisotropy film CoFeB can be changed by adjusting the period number of the first and second perpendicular magnetic anisotropy films. The perpendicular magnetic anisotropy film with a large period number is more difficult to be flipped by the external magnetic field, such as [the first perpendicular magnetic anisotropy film] n1 / Ru / [Second perpendicular magnetic anisotropy film] n2 / W / CoFeB structure, when n1>n2, the first perpendicular magnetic anisotropic film is more difficult to be flipped by the external magnetic field, so the out-of-plane magnetic field intensity gradually decreases from the positive saturation field to less than the exchange bias field H ex After that, the magnetic moment of the second perpendicular magnetic anisotropic film is preferentially flipped, which makes the magnetic moment of the third perpendicular magnetic anisotropic film CoFeB oriented downward, as shown in Figure 4 As shown, on the contrary, when n1<n2, the CoFeB magnetic moment is oriented upward. Based on these two opposite perpendicular magnetic moment orientation states of the CoFeB layer, the differential output structure design of the Wheatstone bridge can be completed, as shown in Figure 5 shown.

[0053] For the in-plane magnetic anisotropic film CoFeB layer (1.8~3nm), the thicker the CoFeB thickness, the larger the out-of-plane saturation field, the wider the linear output range that the sensor can obtain, that is, the wider the current detection range. Therefore, under the premise that the perpendicular magnetic anisotropic film has a large exchange bias field, the thickness of the in-plane magnetic anisotropic film CoFeB layer can be adjusted to appropriately widen the linear output range of the sensor, thereby realizing high sensitivity and wide range applications of closed-loop TMR current sensors, such as Figure 6 shown.

[0054] In summary, the present invention can regulate the current detection sensitivity and range of the closed-loop TMR current sensor based on the interlayer exchange coupling between the perpendicular magnetic anisotropic films. This design method makes the TMR element perfectly match the air gap structure of the closed-loop current sensor. When used, it has the advantages of simple structure, low power consumption, strong adaptability to harsh environments, high precision, high sensitivity, and wide range.

[0055] A closed-loop TMR current sensor with a wide current detection range based on interlayer exchange coupling is proposed. The sensor chip probe is prepared on a wafer using photolithography and magnetron sputtering thin film deposition processes. The TMR thin film preparation process is a standard process condition in the industry and is well known to technical personnel in the industry. It will not be described in detail here. The main steps are briefly described as follows.

[0056] Step 1: Select Si / SiO 2 The wafer is used as a substrate on which a Wheatstone bridge R is prepared. 1 With R 4 The magnetic tunnel junction is deposited by magnetron sputtering equipment in sequence. Ta(5nm) / [Pd(0.8nm) / CoFeB(0.6nm)] 3 / Ru(0.45nm) / [CoFeB(0.6nm) / Pd(0.8nm)] 4 / CoFeB(0.6nm) / W(0.3nm) / CoFeB(1nm) / MgO(1.6nm) / CoFeB(2.2nm) / Ta(5nm), the period number of the first perpendicular magnetic anisotropic film is less than the period number of the second perpendicular magnetic anisotropic film, and the magnetic field is reduced from the out-of-plane positive saturation field to less than H ex The magnetic moment of the third perpendicular magnetic anisotropic film CoFeB is oriented upward, as shown in Figure 5 shown.

[0057] Step 2: On Si / SiO 2 Preparation of Wheatstone bridge R on wafer substrate 2 With R 3 The magnetic tunnel junction is deposited by magnetron sputtering equipment in sequence. Ta(5nm) / [Pd(0.8nm) / CoFeB(0.6nm)] 5 / Ru(0.45nm) / [CoFeB(0.6nm) / Pd(0.8nm)] 2 / CoFeB(0.6nm) / W(0.3nm) / CoFeB(1nm) / MgO(1.6nm) / CoFeB(2.2nm) / Ta(5nm), the period number of the first perpendicular magnetic anisotropic film is greater than the period number of the second perpendicular magnetic anisotropic film, and the magnetic field is reduced from the out-of-plane positive saturation field to less than H ex After the third perpendicular magnetic anisotropic film CoFeB magnetic moment is oriented downward, such as Figure 5 shown.

[0058] Step 3: After the overall preparation of the Wheatstone bridge is completed, the current detection function test can be carried out. The sensor chip probe is placed in an out-of-plane magnetic field environment perpendicular to the membrane surface. 1 ~H 2 Within the range (H 1 , H 2 The size is smaller than H ex ) By changing the out-of-plane magnetic field, the linear output curve of the Wheatstone bridge can be measured, and its voltage output V OUT It changes linearly with the change of the out-of-plane magnetic field, such as Figure 6 shown.

[0059] The closed-loop TMR current sensor of the present invention increases the exchange bias field of the perpendicular magnetic anisotropic film by utilizing the interlayer exchange coupling effect between the multilayer films, and at the same time broadens the linear output range of the current sensor based on the large out-of-plane saturation field of the in-plane magnetic anisotropic film (the linear output range can reach ±2000Gs), and the current detection range is greatly improved. At the same time, the closed-loop TMR current sensor of the present invention has good matching with the magnetic core air gap, simple structure, high sensitivity, high precision, good stability, fast response speed and other performance advantages, which can overcome the shortcomings of current sensors in the current market and realize high-performance current detection applications.

[0060] The above descriptions are only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A wide-range closed-loop TMR current sensor based on interlayer exchange coupling, characterized in that: The invention comprises a substrate, a buffer layer, a perpendicular magnetic anisotropic film, an oxide tunneling layer, an in-plane magnetic anisotropic film and a protective layer which are arranged in sequence from bottom to top, wherein: The substrate is a silicon-based wafer, the surface of which is oxidized with SiO2 to improve the adhesion of the electronic film and the surface roughness of the wafer; The buffer layer is a non-magnetic metal and is used to improve the surface roughness of the wafer and enhance the performance of the magnetic film; The perpendicular magnetic anisotropic film is an artificial synthetic antiferromagnetic structure designed based on interlayer exchange coupling, including a plurality of perpendicular magnetic anisotropic film layers that form antiferromagnetic coupling and ferromagnetic coupling through a non-magnetic layer; The oxide tunneling layer is made of MgO having a spin electron filtering effect; The in-plane magnetic anisotropic film is made of CoFeB with a high spin polarization rate, and its thickness is set to achieve in-plane magnetic anisotropy while obtaining a magnetoresistance change rate of 50% to 150%; The protective layer is used to protect the magnetic film from being oxidized and contaminated by the external environment.

2. A wide-range closed-loop TMR current sensor based on interlayer exchange coupling according to claim 1, characterized in that: The artificial antiferromagnetic structure of the perpendicular magnetic anisotropic film is specifically: [first perpendicular magnetic anisotropic film] / non-magnetic Ru layer / [second perpendicular magnetic anisotropic film] / non-magnetic W layer / [third perpendicular magnetic anisotropic film-CoFeB], wherein the first and second perpendicular magnetic anisotropic films form an antiferromagnetic coupling through the non-magnetic Ru layer, and the second and third perpendicular magnetic anisotropic films form a ferromagnetic coupling through the non-magnetic W layer.

3. A wide-range closed-loop TMR current sensor based on interlayer exchange coupling according to claim 2, characterized in that: The first and second perpendicular magnetic anisotropic films adopt a film structure of [Pt / CoFeB]n, [Pd / CoFeB]n, [Co / Pt]n or [Co / Pd]n, wherein n is the number of periods, and these film structures obtain perpendicular magnetic anisotropy through orbital hybridization.

4. A wide-range closed-loop TMR current sensor based on interlayer exchange coupling according to claim 2, characterized in that: By adjusting the period numbers of the first and second perpendicular magnetic anisotropic films and changing the magnetic moment orientation of the third perpendicular magnetic anisotropic film CoFeB, the differential output structure design of the Wheatstone bridge is realized.

5. A wide-range closed-loop TMR current sensor based on interlayer exchange coupling according to claim 1, characterized in that: The thickness of the in-plane magnetic anisotropic film CoFeB is 1.8~3nm to obtain a magnetoresistance change rate of 50%~150% and increase the device sensitivity.

6. A wide-range closed-loop TMR current sensor based on interlayer exchange coupling according to claim 1, characterized in that: The thickness of the out-of-plane magnetic anisotropic film CoFeB is 0.8~1.4nm, and it can be orbitally hybridized with MgO to overcome the demagnetization field to obtain perpendicular magnetic anisotropy. As the thickness increases, the magnetization direction of CoFeB will gradually change from out-of-plane magnetic anisotropy to in-plane magnetic anisotropy.

7. A wide-range closed-loop TMR current sensor based on interlayer exchange coupling according to claim 1, characterized in that: The material of the protective layer includes Ta, Pt, and AlOx.

8. The wide-range closed-loop TMR current sensor based on interlayer exchange coupling according to claim 1, characterized in that: The thickness of SiO2 oxidized on the surface of the substrate is 300-500nm.

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