Full-bridge magnetoresistive sensor and manufacturing method thereof, and double-pinned magnetoresistive multilayer film

Abstract

The application provides a full-bridge magnetoresistance sensor and a manufacturing method thereof and a double-pinning magnetoresistance multilayer film, wherein the full-bridge magnetoresistance sensor comprises a first double-pinning magnetoresistance multilayer film to a fourth double-pinning magnetoresistance multilayer film, one end of the first double-pinning magnetoresistance multilayer film and one end of the second double-pinning magnetoresistance multilayer film are connected with a power supply end; the other end of the first double-pinning magnetoresistance multilayer film and one end of the third double-pinning magnetoresistance multilayer film are connected with a first signal end; the other end of the second double-pinning magnetoresistance multilayer film and one end of the fourth double-pinning magnetoresistance multilayer film are connected with a second signal end; the other end of the third double-pinning magnetoresistance multilayer film and the other end of the fourth double-pinning magnetoresistance multilayer film are connected with a ground end. The full-bridge magnetoresistance sensor is sequentially subjected to first annealing and second annealing. Compared with the prior art, the application can realize the single-chip full-bridge function, has a small zero point, has a simple annealing process and low cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of magnetic sensor, in particular to a double pinning magnetoresistive multilayer film, a full-bridge magnetoresistive sensor using the double pinning magnetoresistive multilayer film and a manufacturing method thereof.

BACKGROUND

[0002] In order to realize the full-bridge function, the traditional magnetoresistive sensor usually adopts two methods. Method 1: two chips are used, one of which is rotated 180 degrees relative to the other, and the full-bridge function is realized by wire interconnection. Method 2: the magnetic moment of the magnetoresistive sensitive area is locally programmed by laser local heating to realize the full-bridge function. The disadvantage of method 1 is that the assembly process is complex and the zero point of the magnetoresistive sensor is large. The disadvantage of method 2 is that the annealing process is complex and the cost is high.

[0003] Therefore, it is necessary to propose a technical scheme to overcome the above problems.

SUMMARY

[0004] One of the purposes of the present application is to provide a full-bridge magnetoresistive sensor and a manufacturing method thereof as well as a double pinning magnetoresistive multilayer film, which can not only realize the single-chip full-bridge function, but also has a small zero point, a simple annealing process and low cost.

[0005] According to one aspect of the present application, the present application provides a double pinning magnetoresistive multilayer film, which comprises a buffer layer, a first anti-ferromagnetic layer, a first ferromagnetic layer, a first interlayer, a ferromagnetic reference layer, a spacer layer, a ferromagnetic free layer, a second interlayer, a second ferromagnetic layer, a second anti-ferromagnetic layer and a cover layer which are sequentially stacked, the first anti-ferromagnetic layer applies a first exchange bias to the first ferromagnetic layer; the first ferromagnetic layer applies a first artificial anti-ferromagnetic coupling to the ferromagnetic reference layer through the first interlayer; the second anti-ferromagnetic layer applies a second exchange bias to the second ferromagnetic layer; and the second ferromagnetic layer applies a second artificial anti-ferromagnetic coupling to the ferromagnetic free layer through the second interlayer.

[0006] According to another aspect of the present application, the present application provides a full-bridge magnetoresistive sensor, which comprises a first double-pinning magnetoresistive multilayer film, a second double-pinning magnetoresistive multilayer film, a third double-pinning magnetoresistive multilayer film and a fourth double-pinning magnetoresistive multilayer film, one end of the first double-pinning magnetoresistive multilayer film and one end of the second double-pinning magnetoresistive multilayer film are connected with a power supply end; the other end of the first double-pinning magnetoresistive multilayer film and one end of the third double-pinning magnetoresistive multilayer film are connected with a first signal end; the other end of the second double-pinning magnetoresistive multilayer film and one end of the fourth double-pinning magnetoresistive multilayer film are connected with a second signal end; the other end of the third double-pinning magnetoresistive multilayer film and the other end of the fourth double-pinning magnetoresistive multilayer film are connected with a ground end, and the full-bridge magnetoresistive sensor is sequentially subjected to a first annealing and a second annealing. The double-pinning magnetoresistive multilayer film comprises a buffer layer, a first anti-ferromagnetic layer, a first ferromagnetic layer, a first spacer layer, a ferromagnetic reference layer, a spacer layer, a ferromagnetic free layer, a second spacer layer, a second ferromagnetic layer, a second anti-ferromagnetic layer and a capping layer which are sequentially arranged, the first anti-ferromagnetic layer applies a first exchange bias to the first ferromagnetic layer; the first ferromagnetic layer applies a first artificial anti-ferromagnetic coupling to the ferromagnetic reference layer through the first spacer layer; the second anti-ferromagnetic layer applies a second exchange bias to the second ferromagnetic layer; and the second ferromagnetic layer applies a second artificial anti-ferromagnetic coupling to the ferromagnetic free layer through the second spacer layer.

[0007] According to another aspect of the present application, the present application provides a full-bridge magnetoresistive sensor, which comprises a first double-pinning magnetoresistive multilayer film, a second double-pinning magnetoresistive multilayer film, a third double-pinning magnetoresistive multilayer film and a fourth double-pinning magnetoresistive multilayer film, one end of the first double-pinning magnetoresistive multilayer film and one end of the second double-pinning magnetoresistive multilayer film are connected with a power supply end; the other end of the first double-pinning magnetoresistive multilayer film and one end of the third double-pinning magnetoresistive multilayer film are connected with a first signal end; the other end of the second double-pinning magnetoresistive multilayer film and one end of the fourth double-pinning magnetoresistive multilayer film are connected with a second signal end; the other end of the third double-pinning magnetoresistive multilayer film and the other end of the fourth double-pinning magnetoresistive multilayer film are connected with a ground end, and the full-bridge magnetoresistive sensor is sequentially subjected to a first annealing and a second annealing. The double-pinning magnetoresistive multilayer film comprises a buffer layer, a first anti-ferromagnetic layer, a first ferromagnetic layer, a first spacer layer, a ferromagnetic reference layer, a spacer layer, a ferromagnetic free layer, a second spacer layer, a second ferromagnetic layer, a second anti-ferromagnetic layer and a capping layer which are sequentially arranged, the first anti-ferromagnetic layer applies a first exchange bias to the first ferromagnetic layer; the first ferromagnetic layer applies a first artificial anti-ferromagnetic coupling to the ferromagnetic reference layer through the first spacer layer; the second anti-ferromagnetic layer applies a second exchange bias to the second ferromagnetic layer; and the second ferromagnetic layer applies a second artificial anti-ferromagnetic coupling to the ferromagnetic free layer through the second spacer layer.

[0008] Compared with the prior art, the full-bridge magnetoresistance sensor in the application adopts a double-pinning magnetoresistance multilayer film, and through twice global annealing, not only the single-chip full-bridge function can be realized, but also the zero point is small, the annealing process is simple, and the cost is low. BRIEF DESCRIPTION OF DRAWINGS

[0009] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor. Among them:

[0010] Figure 1 FIG. 1 is a structural schematic diagram of a double-pinning magnetoresistance multilayer film of a full-bridge magnetoresistance sensor in an embodiment of the application;

[0011] Figure 2 FIG. 2 is a structural schematic diagram of the full-bridge magnetoresistance sensor in the first annealing in an embodiment of the application;

[0012] Figure 3 FIG. 3 is a structural schematic diagram of the full-bridge magnetoresistance sensor in the second annealing in an embodiment of the application;

[0013] Figure 4 FIG. 4 is a structural schematic diagram of the ferromagnetic free layer of the full-bridge magnetoresistance sensor in the second annealing in an embodiment of the application;

[0014] Figure 5 FIG. 5 is a structural schematic diagram of the magnetization intensity direction of the ferromagnetic reference layer and the ferromagnetic free layer of the full-bridge magnetoresistance sensor in the second annealing in an embodiment of the application;

[0015] Figure 6 FIG. 6 is a response relationship curve of the output of the full-bridge magnetoresistance sensor to the magnetic field after the first annealing and the second annealing in an embodiment of the application;

[0016] Figure 7 FIG. 7 is a flowchart of the manufacturing method of the full-bridge magnetoresistance sensor in an embodiment of the application. DETAILED DESCRIPTION

[0017] In order to make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the application will be further described in detail below with reference to the drawings and specific embodiments.

[0018] The term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to separate or selective embodiments that are mutually exclusive of other embodiments. Unless otherwise specified, the terms "connected," "connected," and "connected" herein, indicating electrical connection, refer to direct or indirect electrical connection.

[0019] According to one aspect of the present invention, a double-pinned magnetoresistive multilayer film is provided.

[0020] See also Figure 1 , which is a schematic structural diagram of a double-pinned magnetoresistive multilayer film of a full-bridge magnetoresistive sensor in one embodiment of the present invention. Figure 1 The double-pinned magnetoresistance multilayer film shown includes: a buffer layer 101, a first antiferromagnetic layer 102, a first ferromagnetic layer 103, a first interlayer 104, a ferromagnetic reference layer 105, a spacer layer 106, a ferromagnetic free layer 107, a second interlayer 108, a second ferromagnetic layer 109, a second antiferromagnetic layer 110 and a covering layer 111 stacked in sequence from bottom to top.

[0021] The buffer layer 101 is a conductive metal or a metal multilayer film, preferably Ta or Ru; the first antiferromagnetic layer 102 is PtMn; the first ferromagnetic layer 103 is a ferromagnetic metal or alloy, preferably Fe, Co, Ni or CoFe(B); the first interlayer 104 is a metal layer, preferably Ru; the ferromagnetic reference layer 105 is a ferromagnetic metal or alloy, preferably Fe, Co, Ni or CoFe(B); for tunneling magnetoresistance (TMR), the spacer layer 106 is a barrier layer, preferably MgO, Al2O3, MgAl 2O4 or MgZnO, for giant magnetoresistance (GMR), the spacer layer 106 is a metal layer, preferably Cu; the ferromagnetic free layer 107 is a ferromagnetic metal or alloy, preferably Fe, Co, Ni or CoFe(B); the second interlayer 108 is a metal layer, preferably Ru; the second ferromagnetic layer 109 is a ferromagnetic metal or alloy, preferably Fe, Co, Ni or CoFe(B); the second antiferromagnetic layer 110 is IrMn or FeMn; the covering layer 111 is a conductive metal or a metal multilayer film, preferably Ta or Ru. In which, the first antiferromagnetic layer 102 applies a first exchange bias to the first ferromagnetic layer 103, the first ferromagnetic layer 103 applies a first artificial antiferromagnetic coupling to the ferromagnetic reference layer 105 through the first interlayer 104, the second antiferromagnetic layer 110 applies a second exchange bias to the second ferromagnetic layer 109, the second ferromagnetic layer 109 applies a second artificial antiferromagnetic coupling to the ferromagnetic free layer 107 through the second interlayer 108, and the aspect ratio of the double-pinned magnetoresistance multilayer film 100 is at least 2.

[0022] According to another aspect of the present invention, the present invention provides a full-bridge magnetoresistive sensor.

[0023] See also Figure 2 , which is a schematic structural diagram of a full-bridge magnetoresistive sensor during the first annealing in one embodiment of the present invention. Figure 2 The full-bridge magnetoresistive sensor shown includes a first double-pinned magnetoresistive multilayer film 100a, a second double-pinned magnetoresistive multilayer film 100b, a third double-pinned magnetoresistive multilayer film 100c, and a fourth double-pinned magnetoresistive multilayer film 100d. Figure 1 The double-pinned magnetoresistive multilayer film shown in FIG. 1 includes one end of the first double-pinned magnetoresistive multilayer film 100a and one end of the second double-pinned magnetoresistive multilayer film 100b connected to the power supply terminal VDD, the other end of the first double-pinned magnetoresistive multilayer film 100a and one end of the third double-pinned magnetoresistive multilayer film 100c connected to the first signal terminal Vp, the other end of the second double-pinned magnetoresistive multilayer film 100b and one end of the fourth double-pinned magnetoresistive multilayer film 100d connected to the second signal terminal Vn, and the other end of the third double-pinned magnetoresistive multilayer film 100c and the other end of the fourth double-pinned magnetoresistive multilayer film 100d connected to the ground terminal GND.

[0024] For ease of description, an xy plane coordinate system is defined, wherein the x-axis extends from left to right, the y-axis extends from bottom to top, and the x-axis and y-axis are perpendicular to each other. The long sides of the first and fourth dual-pinned magnetoresistive multilayer films 100a and 100d are parallel and form a non-parallel and non-perpendicular angle θ1 with the x-axis. Preferably, the angle is between 5 degrees and 85 degrees. The long sides of the second and third dual-pinned magnetoresistive multilayer films 100b and 100c are parallel and form a non-parallel and non-perpendicular angle θ2 with the x-axis; θ1 + θ2 = 180 degrees. The first annealing step includes: increasing the temperature from room temperature to a first temperature T1, applying a magnetic field H along the x-axis, and decreasing the temperature from the first temperature T1 to room temperature. The first annealing defines the magnetocrystalline anisotropy of the first ferromagnetic layer 103, the ferromagnetic reference layer 105, the ferromagnetic free layer 107, and the second ferromagnetic layer 109, and also defines the magnetization direction (along the +x direction) of the first ferromagnetic layer 103, the first exchange bias (along the +x direction), and the magnetization direction (along the -x direction) of the ferromagnetic reference layer 105. Figure 2In the specific embodiment shown, the magnetocrystalline anisotropy of the first ferromagnetic layer 103, the ferromagnetic reference layer 105, the ferromagnetic free layer 107 and the second ferromagnetic layer 109 is parallel to the X-axis (or the direction of the magnetic field H); the magnetization direction of the first ferromagnetic layer 103 is along the +x direction, the first exchange bias is along the +x direction, and the magnetization direction of the ferromagnetic reference layer 105 is along the -x direction. In other words, the magnetization direction of the first ferromagnetic layer 103, the first exchange bias and the magnetization direction of the ferromagnetic reference layer 105 are parallel to the X-axis (or the direction of the magnetic field H), and the magnetization direction of the first ferromagnetic layer 103 and the first exchange bias are opposite to the magnetization direction of the ferromagnetic reference layer 105.

[0025] See also Figure 3 , which is a schematic diagram of the structure of a full-bridge magnetoresistive sensor during the second annealing process in one embodiment of the present invention. The second annealing process includes: increasing the temperature from room temperature to a second temperature T2, without applying a magnetic field, and then decreasing the temperature from the second temperature T2 to room temperature, wherein the second temperature T2 is greater than the blocking temperature of the second antiferromagnetic layer 110 and less than the first temperature T1. The second annealing process utilizes shape anisotropy and magnetocrystalline anisotropy to define the magnetization direction of the second ferromagnetic layer 109, the second exchange bias, and the magnetization direction of the ferromagnetic free layer 107. In one embodiment, the first temperature T1 is between 270°C and 350°C; the second temperature T2 is between 170°C and 350°C; and the magnetic field H is between 3000G and 30000G.

[0026] To illustrate the magnetization direction of the second ferromagnetic layer 109, the second exchange bias and the magnetization direction of the ferromagnetic free layer 107, the ferromagnetic free layer 107a in the first double pinned magnetoresistive multilayer film 100a is taken as an example. Figure 4 As shown in FIG, it is a schematic diagram of the structure of the ferromagnetic free layer of the full-bridge magnetoresistive sensor in one embodiment of the present invention after the second annealing. Figure 4 As shown, the magnetocrystalline anisotropy axis 401 is along the x-axis (or the direction of the magnetic field H), the shape anisotropy axis 402 is along the long side of the double-pinned magnetoresistive multilayer film 100a and is at an angle ε to the x-axis (or the direction of the magnetic field H), and the effective anisotropy axis 403 is at an angle δ to the x-axis. According to the principle of minimum energy, the magnetization direction of the ferromagnetic free layer 107a can be determined to be 180+δ, where δ=ε-0.5atan{K1sin(2ε) / [K d +K1cos(2ε)]}, K1 is the magnetocrystalline anisotropy energy, K dis the shape anisotropy energy, ε is the angle between the shape anisotropy axis 402 of the ferromagnetic free layer 107a after the second annealing and the x-axis, which is along the long side of the first dual-pinned magnetoresistive multilayer film 100a. δ is the angle between the effective anisotropy axis 403 of the ferromagnetic free layer 107a of the first dual-pinned magnetoresistive multilayer film 100a after the second annealing and the x-axis. The magnetocrystalline anisotropy axis 401 of the ferromagnetic free layer 107a of the first dual-pinned magnetoresistive multilayer film 100a after the second annealing is along the x-axis. In other words, the second annealing defines the magnetization directions of the second ferromagnetic layer 109, the second exchange bias, and the ferromagnetic free layer 107 using shape anisotropy and magnetocrystalline anisotropy.

[0027] See also Figure 5 As shown, it is a structural diagram of the magnetization intensity direction of the ferromagnetic reference layer and the ferromagnetic free layer of the full-bridge magnetoresistive sensor in one embodiment of the present invention after the second annealing. Figure 5 As shown, in the first double-pinned magnetoresistive multilayer film 100a, the magnetization intensity direction of the ferromagnetic reference layer 105a is Ma_r, along the -x direction, the magnetization intensity direction of the ferromagnetic free layer 107a is Ma_f, and the angle between the ferromagnetic reference layer 105a and the x-axis (or the direction of the magnetic field H) is 180+δ; in the second double-pinned magnetoresistive multilayer film 100b, the magnetization intensity direction of the ferromagnetic reference layer 105b is Mb_r, along the -x direction, the magnetization intensity direction of the ferromagnetic free layer 107b is Mb_f, and the angle between the ferromagnetic reference layer 105a and the x-axis (or the direction of the magnetic field H) is 180- δ; in the third double-pinned magnetoresistance multilayer film 100c, the magnetization intensity direction of the ferromagnetic reference layer 105c is Mc_r, and along the -x direction, the magnetization intensity direction of the ferromagnetic free layer 107c is Mc_f, and the angle with the x-axis (or the direction of the magnetic field H) is 180-δ; in the fourth double-pinned magnetoresistance multilayer film 100d, the magnetization intensity direction of the ferromagnetic reference layer 105d is Md_r, and along the -x direction, the magnetization intensity direction of the ferromagnetic free layer 107d is Md_f, and the angle with the x-axis (or the direction of the magnetic field H) is 180+δ. Figure 5 The sensitive axis of the full-bridge magnetoresistive sensor shown is perpendicular to the direction of the magnetic field H applied during the first annealing, that is, the sensitive axis is along the y-axis.

[0028] See also Figure 6 As shown in FIG, it is a curve showing the response relationship between the output of the full-bridge magnetoresistive sensor and the magnetic field after the first annealing and the second annealing in one embodiment of the present invention. Figure 6 As shown in the figure, when the external magnetic field is applied along the sensitive axis, the voltage output responds linearly to the external magnetic field within the range of + / -100G, with a sensitivity of 0.4mV / V / G; when the external magnetic field is applied along the non-sensitive axis, the voltage output does not change at all with the external magnetic field.

[0029] According to still another aspect of the present application, the present application provides a manufacturing method of a full-bridge magnetoresistive sensor.

[0030] Referring to Figure 7 Fig. 4 is a flow chart of a manufacturing method of a full-bridge magnetoresistive sensor according to an embodiment of the present application. Figure 7 The manufacturing method of a full-bridge magnetoresistive sensor shown in Fig. 4 comprises the following steps.

[0031] Step 710, providing an initial full-bridge magnetoresistive sensor.

[0032] Step 720, performing first annealing on the full-bridge magnetoresistive sensor.

[0033] Referring to Figure 2 Fig. 5 is a structural schematic diagram of a full-bridge magnetoresistive sensor during first annealing according to an embodiment of the present application. Figure 2 The full-bridge magnetoresistive sensor shown in Fig. 5 comprises a first double-pinning magnetoresistive multilayer film 100a, a second double-pinning magnetoresistive multilayer film 100b, a third double-pinning magnetoresistive multilayer film 100c and a fourth double-pinning magnetoresistive multilayer film 100d, wherein the first double-pinning magnetoresistive multilayer film 100a to the fourth double-pinning magnetoresistive multilayer film 100d can adopt the double-pinning magnetoresistive multilayer film shown in Fig. 2. Figure 1 The double-pinning magnetoresistive multilayer film shown in Fig. 5. Wherein one end of the first double-pinning magnetoresistive multilayer film 100a and one end of the second double-pinning magnetoresistive multilayer film 100b are connected with a power supply end VDD, the other end of the first double-pinning magnetoresistive multilayer film 100a and one end of the third double-pinning magnetoresistive multilayer film 100c are connected with a first signal end Vp, the other end of the second double-pinning magnetoresistive multilayer film 100b and one end of the fourth double-pinning magnetoresistive multilayer film 100d are connected with a second signal end Vn, the other end of the third double-pinning magnetoresistive multilayer film 100c and the other end of the fourth double-pinning magnetoresistive multilayer film 100d are connected with a ground end GND.

[0034] For ease of description, an xy plane coordinate system is defined, wherein the x-axis extends from left to right, the y-axis extends from bottom to top, and the x-axis and y-axis are perpendicular to each other. The long sides of the first and fourth dual-pinned magnetoresistive multilayer films 100a and 100d are parallel and form a non-parallel and non-perpendicular angle θ1 with the x-axis. Preferably, the angle is between 5 degrees and 85 degrees. The long sides of the second and third dual-pinned magnetoresistive multilayer films 100b and 100c are parallel and form a non-parallel and non-perpendicular angle θ2 with the x-axis; θ1 + θ2 = 180 degrees. The first annealing step includes: increasing the temperature from room temperature to a first temperature T1, applying a magnetic field H along the x-axis, and decreasing the temperature from the first temperature T1 to room temperature. The first annealing defines the magnetocrystalline anisotropy of the first ferromagnetic layer 103, the ferromagnetic reference layer 105, the ferromagnetic free layer 107, and the second ferromagnetic layer 109, and also defines the magnetization direction (along the +x direction) of the first ferromagnetic layer 103, the first exchange bias (along the +x direction), and the magnetization direction (along the -x direction) of the ferromagnetic reference layer 105. Figure 2 In the specific embodiment shown, the magnetocrystalline anisotropy of the first ferromagnetic layer 103, the ferromagnetic reference layer 105, the ferromagnetic free layer 107 and the second ferromagnetic layer 109 is parallel to the X-axis (or the direction of the magnetic field H); the magnetization direction of the first ferromagnetic layer 103 is along the +x direction, the first exchange bias is along the +x direction, and the magnetization direction of the ferromagnetic reference layer 105 is along the -x direction. In other words, the magnetization direction of the first ferromagnetic layer 103, the first exchange bias and the magnetization direction of the ferromagnetic reference layer 105 are parallel to the X-axis (or the direction of the magnetic field H), and the magnetization direction of the first ferromagnetic layer 103 and the first exchange bias are opposite to the magnetization direction of the ferromagnetic reference layer 105.

[0035] Step 730: Perform a second annealing on the full-bridge magnetoresistive sensor.

[0036] See also Figure 3 , which is a schematic diagram of the structure of a full-bridge magnetoresistive sensor during the second annealing process in one embodiment of the present invention. The second annealing process includes: increasing the temperature from room temperature to a second temperature T2, without applying a magnetic field, and then decreasing the temperature from the second temperature T2 to room temperature, wherein the second temperature T2 is greater than the blocking temperature of the second antiferromagnetic layer 110 and less than the first temperature T1. The second annealing process utilizes shape anisotropy and magnetocrystalline anisotropy to define the magnetization direction of the second ferromagnetic layer 109, the second exchange bias, and the magnetization direction of the ferromagnetic free layer 107. In one embodiment, the first temperature T1 is between 270°C and 350°C; the second temperature T2 is between 170°C and 350°C; and the magnetic field H is between 3000G and 30000G.

[0037] To illustrate the magnetization direction of the second ferromagnetic layer 109, the second exchange bias and the magnetization direction of the ferromagnetic free layer 107, the ferromagnetic free layer 107a in the first double pinned magnetoresistive multilayer film 100a is taken as an example. Figure 4 As shown in FIG, it is a schematic diagram of the structure of the ferromagnetic free layer of the full-bridge magnetoresistive sensor in one embodiment of the present invention after the second annealing. Figure 4 As shown, the magnetocrystalline anisotropy axis 401 is along the x-axis (or the direction of the magnetic field H), the shape anisotropy axis 402 is along the long side of the double-pinned magnetoresistive multilayer film 100a and is at an angle ε to the x-axis (or the direction of the magnetic field H), and the effective anisotropy axis 403 is at an angle δ to the x-axis. According to the principle of minimum energy, the magnetization direction of the ferromagnetic free layer 107a can be determined to be 180+δ, where δ=ε-0.5atan{K1sin(2ε) / [K d +K1cos(2ε)]}, K1 is the magnetocrystalline anisotropy energy, K d is the shape anisotropy energy, ε is the angle between the shape anisotropy axis 402 of the ferromagnetic free layer 107a after the second annealing and the x-axis, which is along the long side of the first dual-pinned magnetoresistive multilayer film 100a. δ is the angle between the effective anisotropy axis 403 of the ferromagnetic free layer 107a of the first dual-pinned magnetoresistive multilayer film 100a after the second annealing and the x-axis. The magnetocrystalline anisotropy axis 401 of the ferromagnetic free layer 107a of the first dual-pinned magnetoresistive multilayer film 100a after the second annealing is along the x-axis. In other words, the second annealing defines the magnetization directions of the second ferromagnetic layer 109, the second exchange bias, and the ferromagnetic free layer 107 using shape anisotropy and magnetocrystalline anisotropy.

[0038] See also Figure 5 As shown, it is a structural diagram of the magnetization intensity direction of the ferromagnetic reference layer and the ferromagnetic free layer of the full-bridge magnetoresistive sensor in one embodiment of the present invention after the second annealing. Figure 5As shown, the first double pinning magnetoresistive multilayer film 100a, the magnetization direction of the ferromagnetic reference layer 105a is Ma_r, along the -x direction, the magnetization direction of the ferromagnetic free layer 107a is Ma_f, the angle with the x axis (or the magnetic field H direction) is 180+delta; the second double pinning magnetoresistive multilayer film 100b, the magnetization direction of the ferromagnetic reference layer 105b is Mb_r, along the -x direction, the magnetization direction of the ferromagnetic free layer 107b is Mb_f, the angle with the x axis (or the magnetic field H direction) is 180-delta; the third double pinning magnetoresistive multilayer film 100c, the magnetization direction of the ferromagnetic reference layer 105c is Mc_r, along the -x direction, the magnetization direction of the ferromagnetic free layer 107c is Mc_f, the angle with the x axis (or the magnetic field H direction) is 180-delta; the fourth double pinning magnetoresistive multilayer film 100d, the magnetization direction of the ferromagnetic reference layer 105d is Md_r, along the -x direction, the magnetization direction of the ferromagnetic free layer 107d is Md_f, the angle with the x axis (or the magnetic field H direction) is 180+delta. Figure 5 The sensitive axis of the full-bridge magnetoresistive sensor shown is perpendicular to the magnetic field H direction applied by the first annealing, that is, the sensitive axis is along the y axis direction.

[0039] Please refer to Figure 6 As shown, it is the output of the full-bridge magnetoresistive sensor after the first annealing and the second annealing in an embodiment of the present application. As shown Figure 6 As shown, when the external magnetic field is applied along the sensitive axis, in the + / -100G range, the voltage output is linearly responsive to the external magnetic field, and the sensitivity is 0.4mV / V / G; when the external magnetic field is applied along the non-sensitive axis, the voltage output does not change with the external magnetic field.

[0040] In summary, the full-bridge magnetoresistive sensor and the manufacturing method thereof and the double pinning magnetoresistive multilayer film in the present application can not only realize the single-chip full-bridge function through two global annealings, but also have small zero point, simple annealing process and low cost.

[0041] In the present application, the words such as "connection", "connection", "connection", "connection" and the like represent electrical connection, and if no special description is made, it represents direct or indirect electrical connection.

[0042] The above description is only the preferred embodiment of the present application, and the protection scope of the present application is not limited to the above-mentioned embodiment, but any equivalent modification or change made by the ordinary skilled in the art according to the disclosure of the present application shall be included in the protection scope recorded in the claims.

Claims

1. A full-bridge magnetoresistive sensor, characterized in that: The invention comprises a first double-pinned magnetoresistive multilayer film, a second double-pinned magnetoresistive multilayer film, a third double-pinned magnetoresistive multilayer film and a fourth double-pinned magnetoresistive multilayer film. One end of the first double-pinned magnetoresistive multilayer film and one end of the second double-pinned magnetoresistive multilayer film are connected to a power supply terminal; The other end of the first double-pinned magnetoresistive multilayer film and one end of the third double-pinned magnetoresistive multilayer film are connected to the first signal terminal; the other end of the second double-pinned magnetoresistive multilayer film and one end of the fourth double-pinned magnetoresistive multilayer film are connected to the second signal terminal; The other end of the third double-pinned magnetoresistive multilayer film and the other end of the fourth double-pinned magnetoresistive multilayer film are connected to the ground terminal. The full-bridge magnetoresistive sensor undergoes a first annealing and a second annealing in sequence. Each double-pinned magnetoresistive multilayer film includes a buffer layer, a first antiferromagnetic layer, a first ferromagnetic layer, a first interlayer, a ferromagnetic reference layer, a spacer layer, a ferromagnetic free layer, a second interlayer, a second ferromagnetic layer, a second antiferromagnetic layer, and a cap layer stacked in sequence. The first antiferromagnetic layer applies a first exchange bias to the first ferromagnetic layer; The first ferromagnetic layer applies a first artificial antiferromagnetic coupling to the ferromagnetic reference layer through the first interlayer; The second antiferromagnetic layer applies a second exchange bias to the second ferromagnetic layer; The second ferromagnetic layer applies a second artificial antiferromagnetic coupling to the ferromagnetic free layer through the second interlayer. The full-bridge magnetoresistive sensor defines the magnetocrystalline anisotropy of the first ferromagnetic layer, the ferromagnetic reference layer, the ferromagnetic free layer, and the second ferromagnetic layer through a first annealing, and defines the magnetization direction of the first ferromagnetic layer, the first exchange bias, and the magnetization direction of the ferromagnetic reference layer; The first annealing includes: raising the temperature from room temperature to a first temperature T1, applying a magnetic field H, and lowering the temperature from the first temperature T1 to room temperature; Define an xy plane coordinate system, where the X axis and the Y axis are perpendicular to each other, and the direction of the magnetic field H is along the X axis. The full-bridge magnetoresistive sensor is subjected to a second annealing to define the magnetization direction of the second ferromagnetic layer, the second exchange bias, and the magnetization direction of the ferromagnetic free layer by utilizing shape anisotropy and magnetocrystalline anisotropy; The second annealing comprises: raising the temperature from room temperature to a second temperature T2, and reducing the temperature from the second temperature T2 to room temperature without applying a magnetic field, wherein the second temperature T2 is greater than the blocking temperature of the second antiferromagnetic layer and the second temperature T2 is less than the first temperature T1, After the second annealing, The angle between the magnetization intensity direction of the ferromagnetic free layer of the first double-pinned magnetoresistive multilayer film and the X-axis is 180+δ; The angle between the magnetization intensity direction of the ferromagnetic free layer of the second double-pinned magnetoresistive multilayer film and the X-axis is 180-δ; The angle between the magnetization intensity direction of the ferromagnetic free layer of the third double-pinned magnetoresistive multilayer film and the X-axis is 180-δ; The angle between the magnetization intensity direction of the ferromagnetic free layer of the fourth double-pinned magnetoresistive multilayer film and the X-axis is 180+δ; Among them, δ=ε-0.5atan{K1sin(2ε) / [K d +K1cos(2ε)]}, K1 is the magnetocrystalline anisotropy energy, K d is the shape anisotropy energy, ε is the angle between the shape anisotropy axis of the ferromagnetic free layer after the second annealing and the long side of the first double-pinned magnetoresistance multilayer film and the X-axis; δ is the angle between the effective anisotropy axis of the ferromagnetic free layer of the first double-pinned magnetoresistance multilayer film after the second annealing and the X-axis; the magnetocrystalline anisotropy axis of the ferromagnetic free layer of the first double-pinned magnetoresistance multilayer film after the second annealing is along the X-axis.

2. The full-bridge magnetoresistive sensor according to claim 1, wherein: The magnetocrystalline anisotropy of the first ferromagnetic layer, the ferromagnetic reference layer, the ferromagnetic free layer and the second ferromagnetic layer is parallel to the X-axis; The magnetization direction of the first ferromagnetic layer, the first exchange bias, and the magnetization direction of the ferromagnetic reference layer are parallel to the X-axis, and the magnetization direction of the first ferromagnetic layer and the first exchange bias are opposite to the magnetization direction of the ferromagnetic reference layer.

3. The full-bridge magnetoresistive sensor according to claim 1, wherein: The first temperature T1 is between 270°C and 350°C; The second temperature T2 is between 170°C and 350°C; The magnetic field H is between 3000G and 30000G.

4. The full-bridge magnetoresistive sensor according to claim 1, wherein: After the first annealing and the second annealing, the sensitive axis of the full-bridge magnetoresistive sensor is perpendicular to the direction of the magnetic field H applied in the first annealing.

5. The full-bridge magnetoresistive sensor according to claim 1, wherein: The long side of the first double-pinned magnetoresistive multilayer film is parallel to the long side of the fourth double-pinned magnetoresistive multilayer film, and the long side of the first double-pinned magnetoresistive multilayer film forms a non-parallel and non-perpendicular angle θ1 with the X-axis; the long side of the second double-pinned magnetoresistive multilayer film is parallel to the long side of the third double-pinned magnetoresistive multilayer film, and the long side of the second double-pinned magnetoresistive multilayer film forms a non-parallel and non-perpendicular angle θ2 with the X-axis; θ1+θ2=180°, The aspect ratio of the double-pinned magnetoresistive multilayer film is at least 2, The buffer layer is a conductive metal or a metal multilayer film; The first ferromagnetic layer is a ferromagnetic metal or alloy; The first interlayer is a metal layer; The ferromagnetic reference layer is a ferromagnetic metal or alloy; The ferromagnetic free layer is a ferromagnetic metal or alloy; The second interlayer is a metal layer; The second ferromagnetic layer is a ferromagnetic metal or alloy; and / or The covering layer is a conductive metal or a metal multilayer film, The first antiferromagnetic layer is PtMn; For tunneling magnetoresistance, the spacer layer is a barrier layer; For giant magnetoresistance, the spacer layer is a metal layer. When the spacer layer is a barrier layer, the spacer layer is MgO, Al2O3, MgAl2O4 or MgZnO; When the spacer layer is a metal layer, the spacer layer is Cu.

6. The full-bridge magnetoresistive sensor according to claim 5, characterized in that The angle between the long side of the first double-pinned magnetoresistive multilayer film and the X-axis is between 5 degrees and 85 degrees.

7. A method for manufacturing a full-bridge magnetoresistive sensor, characterized in that: It includes: An initial full-bridge magnetoresistive sensor is provided, comprising a first double-pinned magnetoresistive multilayer film, a second double-pinned magnetoresistive multilayer film, a third double-pinned magnetoresistive multilayer film, and a fourth double-pinned magnetoresistive multilayer film, wherein one end of the first double-pinned magnetoresistive multilayer film and one end of the second double-pinned magnetoresistive multilayer film are connected to a power supply terminal; The other end of the first double-pinned magnetoresistive multilayer film and one end of the third double-pinned magnetoresistive multilayer film are connected to the first signal terminal; the other end of the second double-pinned magnetoresistive multilayer film and one end of the fourth double-pinned magnetoresistive multilayer film are connected to the second signal terminal; The other end of the third double-pinned magnetoresistive multilayer film and the other end of the fourth double-pinned magnetoresistive multilayer film are connected to the ground end; The full-bridge magnetoresistive sensor is subjected to a first annealing and a second annealing in sequence. Each double-pinned magnetoresistive multilayer film includes a buffer layer, a first antiferromagnetic layer, a first ferromagnetic layer, a first interlayer, a ferromagnetic reference layer, a spacer layer, a ferromagnetic free layer, a second interlayer, a second ferromagnetic layer, a second antiferromagnetic layer, and a cap layer stacked in sequence. The first antiferromagnetic layer applies a first exchange bias to the first ferromagnetic layer; The first ferromagnetic layer applies a first artificial antiferromagnetic coupling to the ferromagnetic reference layer through the first interlayer; The second antiferromagnetic layer applies a second exchange bias to the second ferromagnetic layer; The second ferromagnetic layer applies a second artificial antiferromagnetic coupling to the ferromagnetic free layer through the second interlayer. The full-bridge magnetoresistive sensor defines the magnetocrystalline anisotropy of the first ferromagnetic layer, the ferromagnetic reference layer, the ferromagnetic free layer, and the second ferromagnetic layer through a first annealing, and defines the magnetization direction of the first ferromagnetic layer, the first exchange bias, and the magnetization direction of the ferromagnetic reference layer; The first annealing comprises: raising the temperature from room temperature to a first temperature T1, applying a magnetic field H, and lowering the temperature from the first temperature T1 to room temperature; Define an xy plane coordinate system, where the X axis and the Y axis are perpendicular to each other, and the direction of the magnetic field H is along the X axis. The full-bridge magnetoresistive sensor is subjected to a second annealing to define the magnetization direction of the second ferromagnetic layer, the second exchange bias, and the magnetization direction of the ferromagnetic free layer by utilizing shape anisotropy and magnetocrystalline anisotropy; The second annealing comprises: raising the temperature from room temperature to a second temperature T2, and reducing the temperature from the second temperature T2 to room temperature without applying a magnetic field, wherein the second temperature T2 is greater than the blocking temperature of the second antiferromagnetic layer and the second temperature T2 is less than the first temperature T1, After the second annealing, The angle between the magnetization intensity direction of the ferromagnetic free layer of the first double-pinned magnetoresistive multilayer film and the X-axis is 180+δ; The angle between the magnetization intensity direction of the ferromagnetic free layer of the second double-pinned magnetoresistive multilayer film and the X-axis is 180-δ; The angle between the magnetization intensity direction of the ferromagnetic free layer of the third double-pinned magnetoresistive multilayer film and the X-axis is 180-δ; The angle between the magnetization intensity direction of the ferromagnetic free layer of the fourth double-pinned magnetoresistive multilayer film and the X-axis is 180+δ; Among them, δ=ε-0.5atan{K1sin(2ε) / [K d +K1cos(2ε)]}, K1 is the magnetocrystalline anisotropy energy, K d is the shape anisotropy energy, ε is the angle between the shape anisotropy axis of the ferromagnetic free layer after the second annealing and the long side of the first double-pinned magnetoresistance multilayer film and the X-axis, δ is the angle between the effective anisotropy axis of the ferromagnetic free layer of the first double-pinned magnetoresistance multilayer film after the second annealing and the X-axis; the magnetocrystalline anisotropy axis of the ferromagnetic free layer of the first double-pinned magnetoresistance multilayer film after the second annealing is along the X-axis.

8. The method for manufacturing a full-bridge magnetoresistive sensor according to claim 7, wherein: The long side of the first double-pinned magnetoresistive multilayer film is parallel to the long side of the fourth double-pinned magnetoresistive multilayer film, and the long side of the first double-pinned magnetoresistive multilayer film forms a non-parallel and non-perpendicular angle θ1 with the X-axis; the long side of the second double-pinned magnetoresistive multilayer film is parallel to the long side of the third double-pinned magnetoresistive multilayer film, and the long side of the second double-pinned magnetoresistive multilayer film forms a non-parallel and non-perpendicular angle θ2 with the X-axis; θ1+θ2=180°, The angle between the long side of the first double-pinned magnetoresistive multilayer film and the X-axis is between 5 degrees and 85 degrees. The aspect ratio of the double-pinned magnetoresistive multilayer film is at least 2, The buffer layer is a conductive metal or a metal multilayer film; The first ferromagnetic layer is a ferromagnetic metal or alloy; The first interlayer is a metal layer; The ferromagnetic reference layer is a ferromagnetic metal or alloy; The ferromagnetic free layer is a ferromagnetic metal or alloy; The second interlayer is a metal layer; The second ferromagnetic layer is a ferromagnetic metal or alloy; and / or The covering layer is a conductive metal or a metal multilayer film, The first antiferromagnetic layer is PtMn; For tunneling magnetoresistance, the spacer layer is a barrier layer; For giant magnetoresistance, the spacer layer is a metal layer. When the spacer layer is a barrier layer, the spacer layer is MgO, Al2O3, MgAl2O4 or MgZnO; When the spacer layer is a metal layer, the spacer layer is Cu.

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