Tunnel magnetoresistance sensor and control method of tunnel magnetoresistance sensor

Abstract

The embodiment of the present application provides a tunnel magnetoresistance sensor and a control method of the tunnel magnetoresistance sensor. The tunnel magnetoresistance sensor comprises: a plurality of magnetic tunnel junctions, the plurality of magnetic tunnel junctions are connected in series between a first port and a second port, and the plurality of magnetic tunnel junctions are used for converting a magnetic signal of an external magnetic field into an electric signal under the condition that a working voltage is applied between the first port and the second port; and a reset circuit, the reset circuit is connected between a third port and a fourth port, the reset circuit is connected with each magnetic tunnel junction, and the reset circuit is used for resetting a magnetic resistance state of the magnetic tunnel junction so that magnetic moments of a free layer and a reference layer of the magnetic tunnel junction are orthogonal under the condition that a reset voltage is applied between the third port and the fourth port, fundamentally solving the problem that a large current needs to be applied to a coil, and further causing the problem of excessive power consumption, so as to reduce power consumption.

Description

Tunnel magnetoresistive sensor and its control method Technical Field

[0001] This application relates to the semiconductor field, and more particularly to a tunnel magnetoresistive sensor and a control method for the tunnel magnetoresistive sensor. Background Technology

[0002] Tunnel magnetoresistance (TMR) sensors are widely used in high-precision magnetic field measurement scenarios such as automotive electronics (e.g., motor control, position detection), industrial automation (e.g., current detection, angle encoding), consumer electronics (e.g., electronic compasses in smartphones), and medical devices (e.g., magnetic resonance imaging assistive systems) due to their high sensitivity, low power consumption, and miniaturization.

[0003] During the use of tunnel magnetoresistive sensors, stray magnetic fields and hysteresis effects can cause zero-point drift. This means that when there is no target magnetic field or the target magnetic field is zero, the output of the tunnel magnetoresistive sensor is not at zero. This defect is fatal for applications requiring high-precision measurements. Existing technology typically deposits a set / reset coil on the tunnel magnetoresistive sensor. This coil is physically isolated from the magnetic tunnel junction (MTJ) of the sensor. The strong magnetic field generated by the coil through a large current can reset the magnetization state of the free layer of the tunnel magnetoresistive sensor to a known reference point, that is, a state where the magnetic moments of the free layer and the reference layer are orthogonal, thereby ensuring that the tunnel magnetoresistive sensor maintains high accuracy.

[0004] However, in this approach, to generate a strong magnetic field sufficient to orthogonalize the magnetic moments of the free layer and the reference layer, the coil needs to withstand a very large instantaneous current for an extremely short period, resulting in excessive power consumption. To address this issue, some solutions employ copper (Cu) interconnects to implement the coil. Since copper has low resistance, it can reduce energy loss to some extent during the application of a large instantaneous current. However, this method cannot change the fundamental requirement of applying a large current to the coil, thus failing to address the problem of excessive power consumption at its root. Summary of the Invention

[0005] This application provides a tunnel magnetoresistive sensor and a control method for the tunnel magnetoresistive sensor, which fundamentally solves the problem of excessive power consumption caused by applying a large current to the coil, thereby reducing power consumption.

[0006] In a first aspect, embodiments of this application provide a tunnel magnetoresistive sensor, comprising:

[0007] Multiple magnetic tunnel junctions are connected in series between a first port and a second port. When an operating voltage is applied between the first port and the second port, the multiple magnetic tunnel junctions are used to convert the magnetic signal of the sensed external magnetic field into an electrical signal.

[0008] A reset circuit is connected between the third port and the fourth port and is connected to each of the magnetic tunnel junctions. When a reset voltage is applied between the third port and the fourth port, the reset circuit is used to reset the magnetoresistive state of the magnetic tunnel junction so that the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction are orthogonal.

[0009] In some embodiments, the first or second film layer of the first magnetic tunnel junction is connected to the first port, and the first or second film layer of the second magnetic tunnel junction is connected to the second port. Both the first and second film layers are conductive, and the first and second magnetic tunnel junctions are two magnetic tunnel junctions located at both ends of the plurality of magnetic tunnel junctions.

[0010] The first film layer of the third magnetic tunnel junction is connected to the first film layer of an adjacent magnetic tunnel junction, and the second film layer of the third magnetic tunnel junction is connected to the second film layer of another adjacent magnetic tunnel junction. The third magnetic tunnel junction is any other magnetic tunnel junction besides the first magnetic tunnel junction and the second magnetic tunnel junction.

[0011] In some embodiments, the first film layer includes a top electrode and / or a heavy metal layer, and the second film layer includes a bottom electrode; or, the second film layer includes the bottom electrode, an antiferromagnetic layer, and a reference layer.

[0012] or;

[0013] The first film layer includes the bottom electrode and / or the heavy metal layer, and the second film layer includes the top electrode, or the second film layer includes the top electrode, the antiferromagnetic layer, and the reference layer.

[0014] In some embodiments, the magnetic tunnel junction comprises, from bottom to top, any of the following membrane layers:

[0015] Bottom electrode, first antiferromagnetic layer, reference layer, barrier layer, free layer, second antiferromagnetic layer, top electrode;

[0016] Alternatively, the structure could be: bottom electrode, second antiferromagnetic layer, free layer, barrier layer, reference layer, first antiferromagnetic layer, and top electrode.

[0017] Alternatively, bottom electrode, antiferromagnetic layer, reference layer, barrier layer, free layer, heavy metal layer, top electrode;

[0018] Alternatively, bottom electrode, heavy metal layer, free layer, barrier layer, reference layer, antiferromagnetic layer, top electrode;

[0019] Alternatively, bottom electrode, antiferromagnetic layer, reference layer, barrier layer, free layer, top electrode;

[0020] Alternatively, bottom electrode, free layer, barrier layer, reference layer, antiferromagnetic layer, top electrode;

[0021] Alternatively, bottom electrode, antiferromagnetic layer, reference layer, barrier layer, free layer, conductive mask layer, top electrode;

[0022] Alternatively, bottom electrode, conductive mask layer, free layer, barrier layer, reference layer, antiferromagnetic layer, top electrode.

[0023] In some embodiments, the reset circuit includes multiple switching units, with the top or bottom electrode of each magnetic tunnel junction connected to the third port and the fourth port respectively via the switching unit;

[0024] When the reset voltage is applied between the third port and the fourth port, the switching unit closes;

[0025] When the operating voltage is applied between the first port and the second port, the switching unit is disconnected.

[0026] In some implementations, the switching unit is any one of a selector, a diode, or a transistor.

[0027] In some implementations, the reset voltage is greater than the operating voltage.

[0028] The tunnel magnetoresistive sensor provided in this application resets the magnetoresistive state of the magnetic tunnel junction by connecting a reset circuit between the third and fourth ports and applying a reset voltage to the magnetic tunnel junction. This achieves orthogonality of the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction. No additional strong magnetic field needs to be applied during the entire reset process. Therefore, there is no need to set up an additional coil to generate a strong magnetic field through a large current for reset. This fundamentally solves the problem of excessive power consumption caused by applying a large instantaneous current to the coil in the prior art. It can improve integration and reduce process compatibility requirements while reducing power consumption. Furthermore, for double-pinned tunnel magnetoresistive sensors, the pinning directions of the free layer and the reference layer must be defined separately through two magnetic field annealing processes. However, this double-pinned film annealing strategy results in poor thermal budget / thermal stability of the free layer, making it susceptible to disturbances from process temperature and ambient temperature, which in turn leads to poor performance and measurement accuracy. The tunnel magnetoresistive sensor provided in this application can solve this problem by resetting the magnetoresistive state of the magnetic tunnel junction through a reset circuit. The reset tunnel magnetoresistive sensor can maintain optimal performance and measurement accuracy. Since post-annealing is no longer required, the various limitations of the aforementioned post-annealing processes are naturally eliminated, resulting in better performance compared to post-annealing processes.

[0029] Secondly, embodiments of this application provide a control method for a tunnel magnetoresistive sensor, applied to the tunnel magnetoresistive sensor as described in the first aspect, the control method comprising:

[0030] A reset voltage in a first direction is applied between the third and fourth ports, and the first and second ports are placed in a high-resistivity state or a floating state so that the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction are orthogonal.

[0031] A working voltage is applied between the first port and the second port, and the third port and the fourth port are placed in a high-resistance state or a floating state to convert the magnetic signal of the sensed external magnetic field into an electrical signal.

[0032] In some embodiments, before applying an operating voltage between the first port and the second port, the control method further includes:

[0033] A reset voltage in a second direction is applied between the third port and the fourth port, and the first port and the second port are placed in a high-resistivity state or a floating state, so that the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction are orthogonal, wherein the second direction is opposite to the first direction.

[0034] In some embodiments, before applying a reset voltage in the first direction between the third and fourth ports, the control method further includes:

[0035] A reset voltage in the first direction is applied between the third port and the fourth port, and the first port and the second port are placed in a high-resistivity state or a floating state so that the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction are orthogonal.

[0036] A magnetic field is applied to the tunnel magnetoresistive sensor, its resistance is detected, and it is determined whether the magnetic field-resistance characteristic of the tunnel magnetoresistive sensor meets a preset standard. If it does not meet the standard, the wafer acceptance test is deemed to have failed; if it does meet the standard, the wafer acceptance test is deemed to have passed. Alternatively, if it does meet the standard, the following steps are executed:

[0037] A reset voltage in a second direction is applied between the third port and the fourth port, and the first port and the second port are placed in a high-resistivity state or a floating state, so that the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction are orthogonal, wherein the second direction is opposite to the first direction;

[0038] A magnetic field is applied to the tunnel magnetoresistive sensor, the resistance of the tunnel magnetoresistive sensor is detected, and it is determined whether the magnetic field-resistance characteristic of the tunnel magnetoresistive sensor meets the preset standard. If it does not meet the standard, the wafer acceptance test is determined to have failed; if it does meet the standard, the wafer acceptance test is determined to have passed.

[0039] The control method for the tunnel magnetoresistive sensor provided in this application resets the magnetoresistive state of the magnetic tunnel junction by applying a reset voltage to the magnetic tunnel junction, thereby achieving orthogonality of the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction. No additional strong magnetic field is required during the entire reset process. Therefore, there is no need to set up an additional coil to generate a strong magnetic field through a large current for reset. This can fundamentally solve the problem of excessive power consumption caused by applying a large instantaneous current to the coil in the prior art. It can improve integration and reduce process compatibility requirements while reducing power consumption. Furthermore, for double-pinned tunnel magnetoresistive sensors, the pinning directions of the free layer and the reference layer must be defined separately through two magnetic field annealing processes. However, this double-pinned film annealing strategy results in poor thermal budget / thermal stability of the free layer, making it susceptible to disturbances from process temperature and ambient temperature, which in turn leads to poor performance and measurement accuracy. The tunnel magnetoresistive sensor provided in this application can solve this problem by resetting the magnetoresistive state of the magnetic tunnel junction through a reset circuit. The reset tunnel magnetoresistive sensor can maintain optimal performance and measurement accuracy. Since post-annealing is no longer required, the various limitations of the aforementioned post-annealing processes are naturally eliminated, resulting in better performance compared to post-annealing processes. Attached Figure Description

[0040] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0041] Figure 1 is a schematic diagram of the circuit principle of a tunnel magnetoresistive sensor provided in this application;

[0042] Figure 2 is a schematic diagram of the circuit principle of a tunnel magnetoresistive sensor provided in this application;

[0043] Figure 3 is a schematic diagram of the film layer of the magnetic tunnel junction in a tunnel magnetoresistive sensor provided in this application;

[0044] Figure 4 is a schematic diagram of the current direction of a tunnel magnetoresistive sensor provided in this application;

[0045] Figure 5 is a schematic diagram of the current direction of a tunnel magnetoresistive sensor provided in this application (II).

[0046] Figure 6 is a schematic diagram of the current direction and magnetic moment direction of a tunnel magnetoresistive sensor provided in this application;

[0047] Figure 7 is a top view of the magnetic moment direction of the tunnel magnetoresistive sensor shown in Figure 6;

[0048] Figure 8 is a schematic diagram of the current direction and magnetic moment direction of a tunnel magnetoresistive sensor provided in this application.

[0049] Figure 9 is a top view of the magnetic moment direction of the tunnel magnetoresistive sensor shown in Figure 8;

[0050] Figure 10 is a schematic diagram of the layout of the tunnel magnetoresistive sensor shown in Figure 2;

[0051] Figure 11 is a cross-sectional schematic diagram of a tunnel magnetoresistive sensor provided in this application;

[0052] Figure 12 is a cross-sectional schematic diagram of a tunnel magnetoresistive sensor provided in this application;

[0053] Figure 13 is a cross-sectional schematic diagram of a tunnel magnetoresistive sensor provided in this application;

[0054] Figure 14 is a cross-sectional schematic diagram of a tunnel magnetoresistive sensor provided in this application;

[0055] Figure 15 is a cross-sectional schematic diagram of a tunnel magnetoresistive sensor provided in this application;

[0056] Figure 16 is a cross-sectional schematic diagram of a tunnel magnetoresistive sensor provided in this application;

[0057] Figure 17 is a cross-sectional schematic diagram of a tunnel magnetoresistive sensor provided in this application;

[0058] Figure 18 is a cross-sectional schematic diagram of a tunnel magnetoresistive sensor provided in this application;

[0059] Figure 19 is a cross-sectional schematic diagram of a tunnel magnetoresistive sensor provided in this application;

[0060] Figure 20 is a flowchart illustrating a control method for a tunnel magnetoresistive sensor provided in this application;

[0061] Figure 21 is a schematic diagram of the structure of a control unit provided in this application.

[0062] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concepts of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0063] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0064] During the use of tunnel magnetoresistive sensors, stray magnetic fields and hysteresis effects can cause zero-point drift, meaning that the output of the tunnel magnetoresistive sensor is not zero when there is no target magnetic field or the target magnetic field is zero. This defect is fatal for applications requiring high-precision measurements. In existing technologies, a set / reset coil is typically deposited on the tunnel magnetoresistive sensor. By applying a large current to this coil, a strong magnetic field is generated, thereby resetting the tunnel magnetoresistive sensor to a state where the magnetic moments of the free layer and the reference layer are orthogonal, thus maintaining high accuracy. However, to generate a strong magnetic field, the coil needs to withstand a very large instantaneous current for an extremely short time, resulting in excessive power consumption.

[0065] To address the aforementioned issues, some solutions employ copper (Cu) interconnects to implement the coil. Due to the low resistance of copper, energy loss during the application of large instantaneous currents can be reduced to some extent. However, this approach cannot change the fact that a large current needs to be applied to the coil, and therefore cannot fundamentally solve the problem of excessive power consumption. Furthermore, this solution has higher requirements for process compatibility, and in order to carry large currents, linewidth miniaturization is limited, resulting in low integration of tunnel magnetoresistive sensor devices.

[0066] In addition to the aforementioned issues, in dual-pinned tunnel magnetoresistive sensors, the magnetic moments of both the reference layer and the free layer are pinned. Considering the need for orthogonality between the pinning directions of the free and reference layers, the pinned portion of the reference layer is more stable, while the pinned portion of the free layer is less stable. From a manufacturing perspective, the pinning directions of the free and reference layers must be defined separately by two magnetic field annealing processes. First, a higher magnetic field strength and annealing temperature are applied to define the pinning direction of the reference layer. Then, a lower magnetic field strength is applied, with the magnetic field direction rotated 90 degrees relative to the previous step, along with a lower annealing temperature, to define the pinning direction of the free layer, ensuring that the pinning direction of the reference layer remains unaffected during this process. However, the annealing strategy of the dual-pinned film results in a low thermal budget and poor thermal stability for the free layer, making it susceptible to disturbances from process and ambient temperatures. This leads to the magnetic moments of the free and reference layers not being perfectly orthogonal, resulting in poor performance and measurement accuracy of the tunnel magnetoresistive sensor.

[0067] Based on the above problems, some solutions involve post-annealing of the double-pinned tunnel magnetoresistive sensor to address the issue of poor thermal stability of the free layer. However, post-annealing also has the following limitations: (1) The post-annealing process window is narrow, making it difficult to achieve optimal performance; (2) High precision is required for controlling the post-annealing temperature and magnetic field. For example, if the post-annealing temperature and magnetic field are too high, it is easy to damage the pinning of the reference layer, affecting the stability of the reference layer pinning. The additional thermal budget will also degrade the overall performance of the device. If the post-annealing temperature and magnetic field are too low, the magnetic moments of the free layer and the reference layer cannot be completely orthogonal, and optimal performance still cannot be achieved.

[0068] To address this, this application proposes a tunnel magnetoresistive sensor, which includes a sensor circuit (detection circuit) composed of multiple magnetic tunnel junctions connected in series to detect external magnetic field signals. Based on this, a reset circuit is constructed using the magnetic tunnel junctions. Under the action of a reset voltage, the reset circuit resets each magnetic tunnel junction to a state where the magnetic moments of the free layer and the reference layer are orthogonal. This solution eliminates the need for an additional strong magnetic field, a coil that generates a strong magnetic field with a large current for resetting, and post-annealing. By applying a reset voltage to the magnetic tunnel junctions to achieve orthogonality between the magnetic moments of the free layer and the reference layer, it fundamentally solves the problem of excessive power consumption caused by applying a large instantaneous current to the coil in existing technologies. This approach reduces power consumption while improving integration and reducing process compatibility requirements, ensuring optimal performance of the tunnel magnetoresistive sensor.

[0069] Figure 1 is a schematic diagram of the circuit principle of a tunnel magnetoresistive sensor provided in an embodiment of this application. As shown in Figure 1, the tunnel magnetoresistive sensor includes:

[0070] Multiple magnetic tunnel junctions are connected in series between a first port 1 and a second port 2. When an operating voltage is applied between the first port 1 and the second port 2, the multiple magnetic tunnel junctions are used to convert the magnetic signal of the sensed external magnetic field into an electrical signal.

[0071] A reset circuit is connected between port 3 and port 4. The reset circuit is connected to each magnetic tunnel junction. When a reset voltage is applied between port 3 and port 4, the reset circuit resets the magnetoresistive state of the magnetic tunnel junction so that the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction are orthogonal. The reset circuit can also be called a reset loop.

[0072] Multiple magnetic tunnel junctions are connected in series between the first port 1 and the second port 2. When an operating voltage is applied, the direction of the magnetic moment of the free layer of each magnetic tunnel junction changes when it is subjected to an external magnetic field, which causes the resistance of the magnetic tunnel junction to change. The resistance of the magnetic tunnel junction is related to the magnitude of the external magnetic field, and the change in resistance of the magnetic tunnel junction can be converted into an electrical signal output, thereby realizing the conversion of the magnetic signal of the external magnetic field into an electrical signal.

[0073] As can be seen from Figure 1, when a reset voltage is applied between the third port 3 and the fourth port 4, the reset voltage can be applied to each magnetic tunnel junction. In other words, the function of the reset circuit is to apply a reset voltage to each magnetic tunnel junction. Under the action of the reset voltage, each magnetic tunnel junction is reset to a state in which the magnetic moments of the free layer and the reference layer are orthogonal.

[0074] Since the magnetoresistive state of the magnetic tunnel junction is reset by applying a reset voltage to the magnetic tunnel junction through a reset circuit, that is, the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction are orthogonal, no additional strong magnetic field is required during the entire reset process. Therefore, there is no need to set up an additional coil to generate a strong magnetic field through a large current for reset. This can fundamentally solve the problem of excessive power consumption caused by applying a large instantaneous current to the coil in the existing technology. It can improve the integration and reduce the process compatibility requirements while reducing power consumption. Furthermore, for double-pinned tunnel magnetoresistive sensors, the pinning directions of the free layer and the reference layer must be defined separately through two magnetic field annealing processes. However, this double-pinned film annealing strategy results in poor thermal budget / thermal stability of the free layer, making it susceptible to disturbances from process temperature and ambient temperature, which in turn leads to poor performance and measurement accuracy. The tunnel magnetoresistive sensor provided in this application can solve this problem by resetting the magnetoresistive state of the magnetic tunnel junction through the aforementioned reset circuit. The reset tunnel magnetoresistive sensor can maintain optimal performance and measurement accuracy. Since post-annealing is no longer required, the various limitations of the aforementioned post-annealing processes are naturally eliminated, resulting in better performance compared to post-annealing processes.

[0075] It should be noted that Figure 1 illustrates the use of four magnetic tunnel junctions MTJ1, MTJ2, MTJ3 and MTJ4 as an example. In actual applications, the number of magnetic tunnel junctions can be set as needed, and this embodiment does not limit this.

[0076] The working principle and reset principle of the tunnel magnetoresistive sensor in this embodiment of the application are explained with reference to Figure 2. Figure 2 still uses four magnetic tunnel junctions as an example for illustration. The film structure of the magnetic tunnel junction in Figure 2 can be referred to Figure 3. From bottom to top, the magnetic tunnel junction includes a bottom electrode 11, a first antiferromagnetic layer 12, a reference layer 13, a barrier layer 14, a free layer 15, a second antiferromagnetic layer 16, and a top electrode 17. The tunnel magnetoresistive sensor shown in Figure 2 is a double-pinned tunnel magnetoresistive sensor, that is, the magnetic moment directions of the reference layer 13 and the free layer 15 are pinned by the first antiferromagnetic layer 12 and the second antiferromagnetic layer 16, respectively. The film structure of its magnetic tunnel junction is only for illustration. The film structure of the magnetic tunnel junction in this embodiment of the application is not limited to this. When the film structure of the magnetic tunnel junction is other, its circuit principle is similar to that shown in Figure 2.

[0077] Referring to Figure 2, the reset circuit includes multiple switching units. The two ends of the top electrode of each magnetic tunnel junction are connected to the third port 3 and the fourth port 4 via switching units, respectively. For example, one end of the top electrode of magnetic tunnel junction MTJ1 is connected to the third port 3 via switching unit K1, and the other end is connected to the fourth port 4 via switching unit K2; one end of the top electrode of magnetic tunnel junction MTJ2 is connected to the third port 3 via switching unit K3, and the other end is connected to the fourth port 4 via switching unit K4; one end of the top electrode of magnetic tunnel junction MTJ3 is connected to the third port 3 via switching unit K3, and the other end is connected to the fourth port 4 via switching unit K5; one end of the top electrode of magnetic tunnel junction MTJ4 is connected to the third port 3 via switching unit K6, and the other end is connected to the fourth port 4 via switching unit K7.

[0078] Optionally, the switching unit can be any of a selector, diode, or transistor. Optionally, the reset voltage in this embodiment is greater than the operating voltage. Optionally, the magnitude of the reset voltage can be related to the type of switching unit. For example, when the switching unit is a selector, assuming the selector's threshold voltage is X, the operating voltage can be less than 2X, and the reset voltage can be greater than 2X.

[0079] When the tunnel magnetoresistive sensor is operating (i.e., in sensor mode), that is, when an operating voltage is applied between the first port 1 and the second port 2, the switching unit is disconnected, as shown in Figure 4, meaning that switching units K1-K7 are all disconnected. In this case, the third port 3 and the fourth port 4 are placed in a high-resistance state or a floating state. The current flow of the tunnel magnetoresistive sensor is shown by the arrows in Figure 4. The current flows through each film layer of each magnetic tunnel junction and through the barrier layer of each magnetic tunnel junction, generating a tunneling magnetoresistive effect, thereby converting the induced magnetic signal into an electrical signal. For example, for magnetic tunnel junction MTJ1, the current enters MTJ1 from the top electrode, flows through each film layer of the magnetic tunnel junction, and then flows out through the bottom electrode; for magnetic tunnel junction MTJ2, the current enters MTJ2 from the bottom electrode, flows through each film layer of the magnetic tunnel junction, and then flows out through the top electrode; other magnetic tunnel junctions follow the same principle.

[0080] When the tunnel magnetoresistive sensor is reset (i.e., in set / reset mode), specifically when a reset voltage is applied between the third port 3 and the fourth port 4, the switching unit closes, as shown in Figure 5, meaning that switching units K1-K7 are all closed. In this case, the first port 1 and the second port 2 are placed in a high-resistance state or a floating state. The current flow of the tunnel magnetoresistive sensor is shown by the arrow in Figure 5. The current flows through the top electrode of the magnetic tunnel junction and the second antiferromagnetic layer, generating an exchange bias-spin orbital torque (EB-SOT) effect, thereby redirecting the magnetic moment of the free layer so that the magnetic moments of the free layer and the reference layer are orthogonal.

[0081] It should be noted that the double-headed arrows in Figure 5 indicate the direction of the current. This means that when the voltage applied between the third port 3 and the fourth port 4 is in a different direction, the corresponding current direction is different. The double-headed arrows in Figure 5 indicate that both current directions can achieve the reset of the magnetoresistive state of the magnetic tunnel junction.

[0082] For example, when the voltage at the third port 3 is higher than the voltage at the fourth port 4, for magnetic tunnel junction MTJ1, the current direction of the top electrode 17 and the second antiferromagnetic layer 16 of MTJ1 is to the right as shown in Figure 6. In this case, the magnetic moment of the free layer 15 is in the inward direction as shown in Figure 6, and the magnetic moment of the reference layer 13 is to the right as shown in Figure 6. The magnetic moments of the free layer 15 and the reference layer 13 are orthogonal as shown in the top view in Figure 7. For magnetic tunnel junction MTJ2, the current direction of the top electrode 17 and the second antiferromagnetic layer 16 of MTJ2 is to the left as shown in Figure 8. In this case, the magnetic moment of the free layer 15 is in the outward direction as shown in Figure 8, and the magnetic moment of the reference layer 13 is to the right as shown in Figure 8. The magnetic moments of the free layer 15 and the reference layer 13 are orthogonal as shown in the top view in Figure 9. Other magnetic tunnel junctions follow the same principle.

[0083] Optionally, when the voltage at the fourth port 4 is higher than the voltage at the third port 3, for magnetic tunnel junction MTJ1, the current directions of the top electrode 17 and the second antiferromagnetic layer 16 are as shown in Figure 8. In this case, the magnetic moment of the free layer 15 is in the outward direction shown in Figure 8, and the magnetic moment of the reference layer 13 is in the rightward direction shown in Figure 8. The magnetic moments of the free layer 15 and the reference layer 13 are orthogonal in the top view shown in Figure 9. For magnetic tunnel junction MTJ2, the current directions of the top electrode 17 and the second antiferromagnetic layer 16 are as shown in Figure 6. In this case, the magnetic moment of the free layer 15 is in the inward direction shown in Figure 6, and the magnetic moment of the reference layer 13 is in the rightward direction shown in Figure 6. The magnetic moments of the free layer 15 and the reference layer 13 are orthogonal in the top view shown in Figure 7. Other magnetic tunnel junctions follow the same principle.

[0084] The circuit diagram above illustrates the circuit principle of the tunnel magnetoresistive sensor. Its structure will be further explained below.

[0085] In some embodiments, the first or second film layer of the first magnetic tunnel junction is connected to the first port, and the first or second film layer of the second magnetic tunnel junction is connected to the second port. Both the first and second film layers are conductive. The first and second magnetic tunnel junctions are two magnetic tunnel junctions located at opposite ends of a plurality of magnetic tunnel junctions.

[0086] The first film layer of the third magnetic tunnel junction is connected to the first film layer of an adjacent magnetic tunnel junction, and the second film layer of the third magnetic tunnel junction is connected to the second film layer of another adjacent magnetic tunnel junction. The third magnetic tunnel junction is any other magnetic tunnel junction besides the first and second magnetic tunnel junctions.

[0087] Optionally, the first film layer includes a top electrode and / or a heavy metal layer, and the second film layer includes a bottom electrode, an antiferromagnetic layer, and a reference layer; or, the second film layer includes a bottom electrode.

[0088] Optionally, the first film layer includes a bottom electrode and / or a heavy metal layer, and the second film layer includes a top electrode, an antiferromagnetic layer, and a reference layer; or, the second film layer includes a top electrode.

[0089] The following is an explanation using specific examples. For instance, Figure 10 is a schematic layout diagram of the tunnel magnetoresistive sensor shown in Figure 2, and Figure 11 is a cross-sectional schematic diagram of the tunnel magnetoresistive sensor shown in Figure 10. Referring to Figures 10 and 11, magnetic tunnel junction MTJ1 is the first magnetic tunnel junction, magnetic tunnel junction MTJ4 is the second magnetic tunnel junction, and magnetic tunnel junctions MTJ2 and MTJ3 are both third magnetic tunnel junctions. The bottom electrode 11, the first antiferromagnetic layer 12, and the reference layer 13 of magnetic tunnel junctions MTJ1 and MTJ2 are connected. The top electrode 17 of magnetic tunnel junctions MTJ2 and MTJ3 is connected. The bottom electrode 11, the first antiferromagnetic layer 12, and the reference layer 13 of magnetic tunnel junctions MTJ3 and MTJ4 are connected. The top electrode 17 of magnetic tunnel junction MTJ1 is used to connect to the first port, and the top electrode 17 of magnetic tunnel junction MTJ4 is used to connect to the second port. In addition, the switching units K1-K7 are connected to the top electrode 17 of each magnetic tunnel junction, and the switching units K1-K7 are connected to the corresponding third or fourth port through the conductive layer 18.

[0090] Optionally, referring to Figure 12, when there are three magnetic tunnel junctions (MTJs), MTJ1 is the first MTJ, MTJ3 is the second MTJ, and MTJ2 is the third MTJ. The bottom electrode 11, the first antiferromagnetic layer 12, and the reference layer 13 of MTJ1 and MTJ2 are connected, and the top electrode 17 of MTJ2 and MTJ3 is connected. The top electrode 17 of MTJ1 is used to connect to the first port, and the bottom electrode 11, the first antiferromagnetic layer 12, and the reference layer 13 of MTJ3 are used to connect to the second port; alternatively, the bottom electrode 11 of MTJ3 is used to connect to the second port.

[0091] Figure 13 is a cross-sectional schematic diagram of the switching unit in the tunnel magnetoresistive sensor shown in Figure 11, where the diodes are the switching unit. Diodes K1-K7 are connected to the top electrode 17 of each magnetic tunnel junction, and diodes K1-K7 are connected to the corresponding third or fourth port through the conductive layer 18. It should be noted that when the switching unit is a diode, when a reset voltage is applied between the third and fourth ports, due to the unidirectional conduction characteristic of the diodes, each magnetic tunnel junction can only be reset when the reset voltage turns on the diodes connected to it.

[0092] Figure 14 is a cross-sectional schematic diagram of the tunnel magnetoresistive sensor shown in Figure 11 after vertical flipping. Each magnetic tunnel junction in the tunnel magnetoresistive sensor shown in Figure 14 includes the following layers from bottom to top: bottom electrode 17, second antiferromagnetic layer 16, free layer 15, barrier layer 14, reference layer 13, first antiferromagnetic layer 12, and top electrode 101. After the tunnel magnetoresistive sensor is flipped, the bottom electrode 11 in Figure 14 becomes the top electrode 101 in Figure 14, and the top electrode 17 in Figure 11 becomes the bottom electrode 107 in Figure 13. In Figure 14, the top electrode 101, first antiferromagnetic layer 12, and reference layer 13 of magnetic tunnel junctions MTJ1 and MTJ2 are connected; the bottom electrode 107 of magnetic tunnel junctions MTJ2 and MTJ3 are connected; and the top electrode 101, first antiferromagnetic layer 12, and reference layer 13 of magnetic tunnel junctions MTJ3 and MTJ4 are connected. The bottom electrode 107 of magnetic tunnel junction MTJ1 is used to connect to the first port, and the bottom electrode 107 of magnetic tunnel junction MTJ4 is used to connect to the second port. Furthermore, the two ends of the bottom electrode 107 of each magnetic tunnel junction are connected to the third port and the fourth port respectively through switching units. For example, switching units K1-K7 are connected to the bottom electrode 107 of each magnetic tunnel junction, and switching units K1-K7 are connected to the corresponding third port or fourth port through conductive layer 18.

[0093] In the embodiments shown in Figures 10 to 14, a reset voltage is applied between the third and fourth ports, causing current to flow through the top electrode 17 and the second antiferromagnetic layer 16 of each magnetic tunnel junction, or through the bottom electrode 107 and the second antiferromagnetic layer 16. This generates an exchange bias-spin orbit torque (EB-SOT) effect, thereby redirecting the magnetic moment of the free layer so that the magnetic moments of the free layer and the reference layer are orthogonal. The magnetoresistance state of the magnetic tunnel junction is reset by the exchange bias-spin orbit torque effect generated by applying a reset voltage to the magnetic tunnel junction. No additional strong magnetic field is required during the reset process. Therefore, it is not necessary to set up a coil to generate a strong magnetic field through a large current for reset. This fundamentally solves the problem of excessive power consumption caused by applying a large instantaneous current to the coil in the prior art. It can improve integration and reduce process compatibility requirements while reducing power consumption. Furthermore, for double-pinned tunnel magnetoresistive sensors, the pinning directions of the free layer and the reference layer must be defined separately through two magnetic field annealing processes. However, this double-pinned film annealing strategy results in poor thermal budget / thermal stability of the free layer, making it susceptible to disturbances from process temperature and ambient temperature, which in turn leads to poor performance and measurement accuracy. The tunnel magnetoresistive sensor provided in this application can solve this problem by resetting the magnetoresistive state of the magnetic tunnel junction through the aforementioned reset circuit. The reset tunnel magnetoresistive sensor can maintain optimal performance and measurement accuracy. Since post-annealing is no longer required, the various limitations of the aforementioned post-annealing processes are naturally eliminated, resulting in better performance compared to post-annealing processes.

[0094] Figure 15 shows a cross-sectional schematic diagram of a single-pinned tunneling magnetoresistive sensor. Each magnetic tunnel junction in the sensor shown in Figure 15, from bottom to top, comprises the following layers: bottom electrode 21, antiferromagnetic layer 22, reference layer 23, barrier layer 24, free layer 25, heavy metal layer 26, and top electrode 27. The bottom electrode 21, antiferromagnetic layer 22, and reference layer 23 of magnetic tunnel junctions MTJ1 and MTJ2 are connected; the heavy metal layer 26 of magnetic tunnel junctions MTJ2 and MTJ3 is connected; and the bottom electrode 21, antiferromagnetic layer 22, and reference layer 23 of magnetic tunnel junctions MTJ3 and MTJ4 are connected. The top electrode 27 and / or heavy metal layer 26 of magnetic tunnel junction MTJ1 are used to connect to the first port, and the top electrode 27 and / or heavy metal layer 26 of magnetic tunnel junction MTJ4 are used to connect to the second port. Furthermore, switching units K1-K7 are connected to the corresponding third or fourth port through conductive layer 28.

[0095] Optionally, based on Figure 15 and referring to Figure 16, the heavy metal layer 26 and top electrode 27 of magnetic tunnel junction MTJ2 and magnetic tunnel junction MTJ3 are connected, the top electrode 27 and / or heavy metal layer 26 of magnetic tunnel junction MTJ1 are used to connect the first port, and the top electrode 27 and / or heavy metal layer 26 of magnetic tunnel junction MTJ4 are used to connect the second port.

[0096] Figure 17 is a cross-sectional schematic diagram of the single-pinned tunnel magnetoresistive sensor shown in Figure 15 after vertical flipping and partial structural changes. Each magnetic tunnel junction in the tunnel magnetoresistive sensor shown in Figure 17, from bottom to top, includes the following layers: bottom electrode 207, heavy metal layer 26, free layer 25, barrier layer 24, reference layer 23, antiferromagnetic layer 22, and top electrode 201. After flipping, the bottom electrode 21 in Figure 15 becomes the top electrode 201 in Figure 17, and the top electrode 27 in Figure 15 becomes the bottom electrode 207 in Figure 17. In Figure 17, the top electrodes 201 of magnetic tunnel junctions MTJ1 and MTJ2 are connected, and the heavy metal layers 26 of magnetic tunnel junctions MTJ2 and MTJ3 are connected. Optionally, the bottom electrodes 207 of magnetic tunnel junctions MTJ2 and MTJ3 can also be connected (not shown in the figure). The top electrodes 201 of magnetic tunnel junctions MTJ3 and MTJ4 are connected. The bottom electrode 207 and / or heavy metal layer 26 of magnetic tunnel junction MTJ1 are used to connect the first port, and the bottom electrode 207 and / or heavy metal layer 26 of magnetic tunnel junction MTJ4 are used to connect the second port.

[0097] In the embodiments shown in Figures 15 to 17, a reset voltage is applied between the third and fourth ports, causing current to flow through the top electrode 27 and heavy metal layer 26 of each magnetic tunnel junction, or through the bottom electrode 207 and heavy metal layer 26, generating a spin-orbit torque (SOT) effect. This redirects the magnetic moment of the free layer, making the magnetic moments of the free layer and the reference layer orthogonal. The resetting of the magnetoresistance state of the magnetic tunnel junction is achieved through the spin-orbit torque effect generated by applying a reset voltage to the magnetic tunnel junction. No additional strong magnetic field is required during the reset process; therefore, there is no need to use a coil to generate a strong magnetic field with a large current for reset. This fundamentally solves the problem of excessive power consumption caused by applying a large instantaneous current to the coil in existing technologies. It can improve integration density and reduce process compatibility requirements while reducing power consumption. Furthermore, for double-pinned tunnel magnetoresistive sensors, the pinning directions of the free layer and the reference layer must be defined separately through two magnetic field annealing processes. However, this double-pinned film annealing strategy results in poor thermal budget / thermal stability of the free layer, making it susceptible to disturbances from process temperature and ambient temperature, which in turn leads to poor performance and measurement accuracy. The tunnel magnetoresistive sensor provided in this application can solve this problem by resetting the magnetoresistive state of the magnetic tunnel junction through the aforementioned reset circuit. The reset tunnel magnetoresistive sensor can maintain optimal performance and measurement accuracy. Since post-annealing is no longer required, the various limitations of the aforementioned post-annealing processes are naturally eliminated, resulting in better performance compared to post-annealing processes.

[0098] Figure 18 is a cross-sectional schematic diagram of a tunneling magnetoresistive sensor with a magnetic field reversal driven by current. Each magnetic tunnel junction in the tunneling magnetoresistive sensor shown in Figure 18, from bottom to top, includes the following layers: bottom electrode 31, antiferromagnetic layer 32, reference layer 33, barrier layer 34, free layer 35, conductive mask layer 36, and top electrode 37. The conductive mask layer 36 can be a hard mask layer. The conductive mask layer 36 is optional; that is, the layers included in the magnetic tunnel junction from bottom to top can also be: bottom electrode 31, antiferromagnetic layer 32, reference layer 33, barrier layer 34, free layer 35, and top electrode 37. The bottom electrode 31, antiferromagnetic layer 32, and reference layer 33 of magnetic tunnel junctions MTJ1 and MTJ2 are connected. The top electrode 37 of magnetic tunnel junctions MTJ2 and MTJ3 are connected. The bottom electrode 31, antiferromagnetic layer 32, and reference layer 33 of magnetic tunnel junctions MTJ3 and MTJ4 are connected. The top electrode 37 of magnetic tunnel junction MTJ1 is used to connect to the first port, and the top electrode 37 of magnetic tunnel junction MTJ4 is used to connect to the second port. In addition, switching units K1-K7 are connected to the top electrode 37 of each magnetic tunnel junction, and switching units K1-K7 are connected to the corresponding third or fourth port through conductive layer 38.

[0099] Figure 19 is a cross-sectional schematic diagram of the tunnel magnetoresistive sensor shown in Figure 18 after vertical flipping. Each magnetic tunnel junction in the tunnel magnetoresistive sensor shown in Figure 19, from bottom to top, includes the following layers: bottom electrode 307, conductive mask layer 36, free layer 35, barrier layer 34, reference layer 33, antiferromagnetic layer 32, and top electrode 301. After flipping, the bottom electrode 31 in Figure 18 becomes the top electrode 301 in Figure 19, and the top electrode 37 in Figure 18 becomes the bottom electrode 307 in Figure 19. The conductive mask layer 36 is optional; that is, the layers included in the magnetic tunnel junction from bottom to top can also be: bottom electrode 307, free layer 35, barrier layer 34, reference layer 33, antiferromagnetic layer 32, and top electrode 301. In Figure 19, the top electrode 301, antiferromagnetic layer 32, and reference layer 33 of magnetic tunnel junctions MTJ1 and MTJ2 are connected; the bottom electrode 307 of magnetic tunnel junctions MTJ2 and MTJ3 are connected; and the top electrode 301, antiferromagnetic layer 32, and reference layer 33 of magnetic tunnel junctions MTJ3 and MTJ4 are connected. The bottom electrode 307 of magnetic tunnel junction MTJ1 is used to connect to the first port, and the bottom electrode 307 of magnetic tunnel junction MTJ4 is used to connect to the second port. Furthermore, the two ends of the bottom electrode 307 of each magnetic tunnel junction are connected to the third and fourth ports respectively through switching units. For example, switching units K1-K7 are connected to the bottom electrode 307 of each magnetic tunnel junction, and switching units K1-K7 are connected to the corresponding third or fourth port through conductive layer 38.

[0100] In the embodiments shown in Figures 18 and 19, a reset voltage is applied between the third and fourth ports, causing current to flow through the top electrode 37 or bottom electrode 307 of each magnetic tunnel junction to generate a magnetic field. This redirects the magnetic moment of the free layer, making the magnetic moments of the free layer and the reference layer orthogonal. The magnetoresistance state of the magnetic tunnel junction is reset by applying a reset voltage to generate a magnetic field. No additional strong magnetic field is required during the reset process; therefore, there is no need to use a coil to generate a strong magnetic field with a large current for reset. This fundamentally solves the problem of excessive power consumption caused by applying a large instantaneous current to the coil in existing technologies. It can improve integration density and reduce process compatibility requirements while reducing power consumption. Furthermore, for double-pinned tunnel magnetoresistive sensors, the pinning directions of the free layer and the reference layer must be defined separately through two magnetic field annealing processes. However, this double-pinned film annealing strategy results in poor thermal budget / thermal stability of the free layer, making it susceptible to disturbances from process temperature and ambient temperature, which in turn leads to poor performance and measurement accuracy. The tunnel magnetoresistive sensor provided in this application can solve this problem by resetting the magnetoresistive state of the magnetic tunnel junction through the aforementioned reset circuit. The reset tunnel magnetoresistive sensor can maintain optimal performance and measurement accuracy. Since post-annealing is no longer required, the various limitations of the aforementioned post-annealing processes are naturally eliminated, resulting in better performance compared to post-annealing processes.

[0101] Figure 20 is a flowchart illustrating a control method for a tunnel magnetoresistive sensor according to an embodiment of this application. The execution entity of this method can be the control unit of the tunnel magnetoresistive sensor. As shown in Figure 20, the control method includes:

[0102] S2001, control the application of a reset voltage in the first direction between the third and fourth ports, and place the first and second ports in a high-resistivity state or a floating state so that the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction are orthogonal.

[0103] S2002, control the application of a reset voltage in the second direction between the third and fourth ports, and place the first and second ports in a high-resistivity state or a floating state, so that the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction are orthogonal, wherein the second direction is opposite to the first direction.

[0104] S2003, control the application of a working voltage between the first and second ports, and place the third and fourth ports in a high-resistance state or a floating state to convert the magnetic signal of the sensed external magnetic field into an electrical signal.

[0105] S2002 is an optional step. The reset voltage in the first direction is compared to the reset voltage in the second direction, with one causing the voltage at the third port to be higher than the voltage at the fourth port, and the other causing the voltage at the fourth port to be higher than the voltage at the third port. By executing S2001 and S2002, the double reset improves reliability, allowing the tunnel magnetoresistive sensor to maintain optimal performance and measurement accuracy. Before each operation of the tunnel magnetoresistive sensor, S2001 or both S2001 and S2002 can be executed to redirect the magnetic moment of the free layer, thereby ensuring high measurement accuracy.

[0106] In this embodiment, the principle and technical effect of applying a reset voltage or operating voltage to the tunnel magnetoresistive sensor can be found in the description of the previous embodiment, and will not be repeated here.

[0107] Based on the above embodiments, the method attempted by this application before the tunnel magnetoresistive sensor is put into operation may further include:

[0108] A reset voltage in the first direction is applied between the third and fourth ports, and the first and second ports are placed in a high-resistivity state or a floating state so that the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction are orthogonal.

[0109] A magnetic field is applied to the tunnel magnetoresistive sensor, its resistance is detected, and it is determined whether the magnetic field-resistance characteristic of the tunnel magnetoresistive sensor meets a preset standard. If it does not meet the standard, the wafer acceptance test is deemed a failure; if it does meet the standard, the wafer acceptance test is deemed a success. Alternatively, if it meets the standard, the following steps are executed:

[0110] A reset voltage in a second direction is applied between the third and fourth ports, and the first and second ports are placed in a high-resistivity state or a floating state, so that the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction are orthogonal, wherein the second direction is opposite to the first direction;

[0111] The system controls the application of a magnetic field to the tunnel magnetoresistive sensor, detects the resistance of the tunnel magnetoresistive sensor, and determines whether the magnetic field-resistance characteristics of the tunnel magnetoresistive sensor meet the preset standard. If it does not meet the standard, the wafer acceptance test is determined to have failed; if it does meet the standard, the wafer acceptance test is determined to have passed.

[0112] After the tunnel magnetoresistive sensor (TMS) is fabricated and fabricated, it undergoes initialization. Initialization can involve one or two resets. With a single reset, a reset voltage in the first direction is applied between the third and fourth ports. If the TMS's magnetic field-resistance characteristics meet a preset standard, the wafer acceptance test passes. With a second reset, the same reset voltage is applied between the third and fourth ports. If the TMS's magnetic field-resistance characteristics again meet the preset standard, a second reset voltage in the second direction is applied. If the TMS's magnetic field-resistance characteristics again meet the preset standard, the wafer acceptance test passes. Applying a reset voltage orthogonals the magnetic moments of the free layer and reference layer of the magnetic tunnel junction, resulting in better performance than post-annealing.

[0113] Figure 21 is a schematic diagram of the control unit provided in this application. As shown in Figure 21, the control unit 211 provided in this embodiment includes at least one processor 2101 and a memory 2102. Optionally, the control unit 211 further includes a communication component 2103. The processor 2101, the memory 2102, and the communication component 2103 are connected via a bus.

[0114] In a specific implementation, at least one processor 2101 executes computer execution instructions stored in memory 2102, causing at least one processor 2101 to perform the above-described method.

[0115] The specific implementation process of processor 2101 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0116] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. A general-purpose processor can be a microcontroller (MCU) or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0117] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0118] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0119] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0120] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method.

[0121] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0122] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an application-specific integrated circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0123] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0124] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0125] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0126] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0127] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0128] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A tunnel magnetoresistive sensor, characterized in that, include: A plurality of magnetic tunnel junctions (MTJs) are connected in series between a first port and a second port. When an operating voltage is applied between the first port and the second port, the MTJs convert the magnetic signal of an induced external magnetic field into an electrical signal. A reset circuit is connected between a third port and a fourth port and is connected to each MTJ. When a reset voltage is applied between the third port and the fourth port, the reset circuit resets the magnetoresistive state of the MTJs to make the magnetic moments of the free layer and the reference layer of the MTJs orthogonal. The reset circuit includes a plurality of switching units. One end of the top electrode or bottom electrode of each MTJ is connected to the third port through the switching unit, and the other end is connected to the fourth port through the switching unit. When the reset voltage is applied between the third port and the fourth port, the switching unit closes. When the operating voltage is applied between the first port and the second port, the switching unit is disconnected.

2. The tunnel magnetoresistive sensor according to claim 1, characterized in that, The first or second film layer of the first magnetic tunnel junction is connected to the first port, and the first or second film layer of the second magnetic tunnel junction is connected to the second port. Both the first and second film layers are conductive. The first and second magnetic tunnel junctions are two magnetic tunnel junctions located at opposite ends of the plurality of magnetic tunnel junctions. The first film layer of the third magnetic tunnel junction is connected to the first film layer of an adjacent magnetic tunnel junction, and the second film layer of the third magnetic tunnel junction is connected to the second film layer of another adjacent magnetic tunnel junction. The third magnetic tunnel junction is any other magnetic tunnel junction besides the first and second magnetic tunnel junctions.

3. The tunnel magnetoresistive sensor according to claim 2, characterized in that, The first film layer includes a top electrode and / or a heavy metal layer, and the second film layer includes a bottom electrode, or the second film layer includes the bottom electrode, an antiferromagnetic layer, and a reference layer; or the first film layer includes the bottom electrode and / or a heavy metal layer, and the second film layer includes a top electrode, or the second film layer includes the top electrode, an antiferromagnetic layer, and a reference layer.

4. The tunnel magnetoresistive sensor according to any one of claims 1-3, characterized in that, The magnetic tunnel junction comprises, from bottom to top, any of the following layers: bottom electrode, first antiferromagnetic layer, reference layer, barrier layer, free layer, second antiferromagnetic layer, and top electrode; or, bottom electrode, second antiferromagnetic layer, free layer, barrier layer, reference layer, first antiferromagnetic layer, and top electrode. Alternatively, bottom electrode, antiferromagnetic layer, reference layer, barrier layer, free layer, heavy metal layer, top electrode; Alternatively, bottom electrode, heavy metal layer, free layer, barrier layer, reference layer, antiferromagnetic layer, top electrode; Alternatively, bottom electrode, antiferromagnetic layer, reference layer, barrier layer, free layer, top electrode; Alternatively, bottom electrode, free layer, barrier layer, reference layer, antiferromagnetic layer, top electrode; Alternatively, the structure could be: bottom electrode, antiferromagnetic layer, reference layer, barrier layer, free layer, conductive mask layer, and top electrode; or bottom electrode, conductive mask layer, free layer, barrier layer, reference layer, antiferromagnetic layer, and top electrode.

5. The tunnel magnetoresistive sensor according to any one of claims 1-3, characterized in that, The switching unit is any one of a selector, a diode, or a transistor.

6. The tunnel magnetoresistive sensor according to any one of claims 1-3, characterized in that, The reset voltage is greater than the operating voltage.

7. A control method for a tunnel magnetoresistive sensor, characterized in that, The control method, applied to the tunnel magnetoresistive sensor as described in any one of claims 1-6, comprises: controlling the application of a reset voltage in a first direction between a third port and a fourth port, and placing the first port and the second port in a high-resistivity state or a floating state, so that the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction are orthogonal; controlling the application of an operating voltage between the first port and the second port, and placing the third port and the fourth port in a high-resistivity state or a floating state, so as to convert the magnetic signal of the sensed external magnetic field into an electrical signal.

8. The control method according to claim 7, characterized in that, Before applying the operating voltage between the first port and the second port, the control method further includes: applying a reset voltage in a second direction between the third port and the fourth port, and placing the first port and the second port in a high-resistivity state or a floating state, so that the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction are orthogonal, wherein the second direction is opposite to the first direction.

9. The control method according to claim 7 or 8, characterized in that, Before applying a reset voltage in the first direction between the third and fourth ports, the control method further includes: applying a reset voltage in the first direction between the third and fourth ports, and placing the first and second ports in a high-resistivity state or a floating state, so that the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction are orthogonal; applying a magnetic field to the tunnel magnetoresistive sensor, detecting the resistance of the tunnel magnetoresistive sensor, and determining whether the magnetic field-resistance characteristics of the tunnel magnetoresistive sensor meet a preset standard; if not, determining that the wafer acceptance test has failed; if it does, determining that the wafer acceptance test has failed. If the test passes, or if the conditions are met, the following steps are executed: A reset voltage in a second direction is applied between the third and fourth ports, and the first and second ports are placed in a high-resistance state or a floating state, so that the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction are orthogonal, wherein the second direction is opposite to the first direction; a magnetic field is applied to the tunnel magnetoresistive sensor, the resistance of the tunnel magnetoresistive sensor is detected, and it is determined whether the magnetic field-resistance characteristic of the tunnel magnetoresistive sensor meets a preset standard. If it does not meet the standard, the wafer acceptance test is determined to have failed; if it does meet the standard, the wafer acceptance test is determined to have passed.

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