CN109633496A

CN109633496A - Single, double axis magnetic field sensor and preparation method and equipment

Info

Publication number: CN109633496A
Application number: CN201811612027.0A
Authority: CN
Inventors: 郭宗夏; 曹志强; 闫韶华; 安琪; 冷群文; 赵巍胜
Original assignee: Qingdao Research Institute Of Beihang University
Current assignee: Qingdao Research Institute Of Beihang University
Priority date: 2018-12-27
Filing date: 2018-12-27
Publication date: 2019-04-16

Abstract

The embodiment of the present application provides a kind of single, double axis magnetic field sensor and preparation method and equipment.Wherein, it includes two first and two second magnetic resistance module groups that single-axis sensors, which include: the first Wheatstone bridge on substrate,；Two first magnetic resistance module groups are located on the first opposite bridge arm of the first Wheatstone bridge, and the reference layer direction of magnetization of the first magnetic resistance module is identical as the first direction of the first sensing shaft of uniaxial magnetic field sensor in the first magnetic resistance module group；Two second magnetic resistance module groups are located on the second opposite bridge arm of the first Wheatstone bridge, and the second magnetic resistance module group includes concatenated two the second magnetic resistance modules；The reference layer direction of magnetization of two second magnetic resistance modules it is parallel with the first sensing shaft at the angular bisector of the first angle；First angle is greater than 0 ° less than 180 °；First magnetic resistance module and the respective reference layer direction of magnetization of the second magnetic resistance module are vertical with respective easy magnetizing axis.Technical solution provided by the present application can reduce uniaxial magnetic field sensor preparation process complexity.

Description

Single-axis and double-axis magnetic field sensor and preparation method and equipment thereof

Technical Field

The application relates to the technical field of semiconductors, in particular to a single-axis and double-axis magnetic field sensor and a preparation method and equipment thereof.

Background

The magnetic field sensor is mainly used for detecting the existence, strength, direction, change and the like of a magnetic field. In addition to direct measurement of magnetic fields, magnetic field sensors also provide a wide range of solutions for the measurement of other physical quantities, such as electrical current, linear displacement, linear velocity, angular displacement, angular velocity, acceleration, etc. Magnetic field sensors of the type that have been used today are Hall (Hall) sensors, Anisotropic (AMR) sensors, Giant Magneto Resistance (GMR) sensors, Tunneling Magneto Resistance (TMR) sensors, etc.

Currently, when manufacturing single-axis magnetic field sensors, a half wheatstone bridge configuration is generally employed. In the prior art, the structure of a half wheatstone bridge is: one opposite bridge arm is provided with a sensing unit, and the other opposite bridge arm is provided with a fixed resistor. Thus, the resistance value of the opposite arm to which the fixed resistance is set will remain unchanged regardless of changes in the external magnetic field. Therefore, when the half Wheatstone bridge is manufactured in the prior art, the sensing unit and the fixed resistor need to be manufactured, the manufacturing process is complex, and the manufacturing cost is high.

Disclosure of Invention

The application provides a single-axis magnetic field sensor, a double-axis magnetic field sensor, a manufacturing method and equipment thereof, which aim to solve the problems that in the prior art, a single-axis magnetic field sensor is complex in manufacturing process and the like.

Thus, in one embodiment of the present application, a single-axis magnetic field sensor is provided. The single-axis magnetic field sensor includes: the magnetic resonance imaging device comprises a substrate and a first Wheatstone bridge positioned on the substrate, wherein the first Wheatstone bridge comprises two first magnetic resistance module groups and two second magnetic resistance module groups; wherein,

the two first magnetic resistance module groups are respectively positioned on a first opposite bridge arm of the first Wheatstone bridge, and the magnetization directions of the reference layers of the first magnetic resistance modules in the first magnetic resistance module groups are the same as the first direction of a first sensing shaft of the uniaxial magnetic field sensor;

the two second reluctance module groups are respectively positioned on the second opposite bridge arms of the first Wheatstone bridge and comprise two second reluctance modules which are connected in series; an angular bisector of a first included angle formed by the magnetization directions of the reference layers of the two second magnetoresistive modules is parallel to the first sensing axis; wherein the first included angle is greater than 0 degrees and less than 180 degrees;

the magnetization directions of the reference layers of the first magneto-resistive module and the second magneto-resistive module are perpendicular to the easy magnetization axes of the first magneto-resistive module and the second magneto-resistive module.

Optionally, the first included angle is greater than 80 ° and less than 100 °.

Optionally, the first included angle is 90 °.

Optionally, the first magnetoresistive module group includes two first magnetoresistive modules connected in series;

the low resistance state of the first magnetic resistance module is equal to the low resistance state of the second magnetic resistance module;

the high-resistance-state resistance value of the first magnetic resistance module is equal to the high-resistance-state resistance value of the second magnetic resistance module.

Optionally, the first reluctance module is formed by connecting Q first reluctance units in series; the second magnetic resistance module is formed by connecting Q second magnetic resistance units in series; the first magnetoresistive unit and the second magnetoresistive unit are the same in shape;

the easy magnetization axes of the Q first magnetic resistance units are parallel to each other;

the easy magnetization axes of the Q second magnetic resistance units are parallel to each other;

wherein Q is a positive integer.

Optionally, a third included angle formed between the magnetization direction of the reference layer of the second magnetoresistive module and the first direction of the first sensing axis is an acute angle.

In yet another embodiment of the present application, a two-axis magnetic field sensor is provided. The two-axis magnetic field sensor includes: a substrate;

a first Wheatstone bridge having a first sensing axis and a second Wheatstone bridge having a second sensing axis on the substrate, wherein the first sensing axis and the second sensing axis are perpendicular to each other;

the first Wheatstone bridge comprises two first magnetic resistance module groups and two second magnetic resistance module groups; the two first magnetic resistance module groups are respectively positioned on a first opposite bridge arm of the first Wheatstone bridge, and the magnetization directions of the reference layers of the first magnetic resistance modules in the first magnetic resistance module groups are the same as the first direction of a first sensing shaft of the uniaxial magnetic field sensor; the two second reluctance module groups are respectively positioned on the second opposite bridge arms of the first Wheatstone bridge and comprise two second reluctance modules which are connected in series; an angular bisector of a first included angle formed by the magnetization directions of the reference layers of the two second magnetoresistive modules is parallel to the first sensing axis; wherein the first included angle is greater than 0 degrees and less than 180 degrees;

the second Wheatstone bridge comprises four third magnetic resistance modules which are respectively positioned on each bridge arm of the second Wheatstone bridge; an angular bisector of a second included angle formed by the magnetization directions of the reference layers of the two third magnetic resistance modules respectively positioned on the adjacent bridge arms of the second Wheatstone bridge is parallel to the first sensing shaft; a second included angle formed by the magnetization directions of the reference layers of the two third magneto-resistance modules respectively positioned on the adjacent bridge arms of the second Wheatstone bridge is larger than 0 degree and smaller than 180 degrees;

the magnetization directions of the respective reference layers of the first magneto-resistive module, the second magneto-resistive module and the third magneto-resistive module are perpendicular to the respective easy magnetization axes.

In another embodiment of the present application, an electronic device is provided. The electronic device includes: the uniaxial magnetic field sensor of any one of the above.

In another embodiment of the present application, an electronic device is provided. The electronic device includes: the two-axis magnetic field sensor of any of the above.

In yet another embodiment of the present application, a method of making a single-axis magnetic field sensor is provided. The preparation method comprises the following steps:

depositing a plurality of layers of films on a substrate in sequence to obtain a stacked layer;

performing imaging etching on the stacked layer to form two first stacked block groups and two second stacked block groups;

preparing a conducting wire on the substrate, wherein the conducting wire is connected with the two first stacking block groups and the two second stacking block groups to form a first bridge structure;

annealing in a magnetic field, and cooling after removing the magnetic field to convert the first stacked block set into a first magnetic resistance module set, convert the second stacked block set into a second magnetic resistance module set, and convert the first bridge structure into a first Wheatstone bridge to obtain a uniaxial magnetic field sensor; wherein,

the two second reluctance module groups are respectively positioned on second opposite bridge arms of the first Wheatstone bridge and comprise two second reluctance modules which are connected in series; an angular bisector of a first included angle formed by the magnetization directions of the reference layers of the two second magnetoresistive modules is parallel to the first sensing axis; wherein the first included angle is greater than 0 degrees and less than 180 degrees;

Optionally, the magnetic field direction of the magnetic field is the same as the first direction of the first sensing axis.

In yet another embodiment of the present application, a method of making a dual-axis magnetic field sensor is provided. The preparation method comprises the following steps:

performing imaging etching on the stacked layer to form two first stacked block groups, two second stacked block groups and four third stacked blocks;

preparing a conducting wire on the substrate, wherein the conducting wire is connected with the two first stacking block groups and the two second stacking block groups to form a first bridge structure; the conducting wires are connected with the four third stacking blocks to form a second bridge structure;

annealing in a magnetic field and cooling after removing the magnetic field to convert the first stacked block set into a first magnetoresistive module set, the second stacked block set into a second magnetoresistive module set, the third stacked block set into a third magnetoresistive module, the first bridge structure into a first Wheatstone bridge, the second bridge structure into a second Wheatstone bridge to obtain a two-axis magnetic field sensor; wherein,

the first Wheatstone bridge has a first sensing axis, and the second Wheatstone bridge has a second sensing axis; wherein the first sensing axis and the second sensing axis are perpendicular to each other;

the four third reluctance modules are respectively positioned on each bridge arm of the second Wheatstone bridge; an angular bisector of a second included angle formed by the magnetization directions of the reference layers of the two third magnetic resistance modules respectively positioned on the adjacent bridge arms of the second Wheatstone bridge is parallel to the first sensing shaft; a second included angle formed by the magnetization directions of the reference layers of the two third magneto-resistance modules respectively positioned on the adjacent bridge arms of the second Wheatstone bridge is larger than 0 degree and smaller than 180 degrees;

In the technical scheme provided by the embodiment of the application, under the action of an external magnetic field perpendicular to a first sensing shaft, the resistance of each bridge arm of a first relative bridge arm is kept unchanged; the resistances of two second reluctance modules on the same bridge arm in a second opposite bridge arm generate opposite responses, so that the resistance of the bridge arm is kept unchanged. Therefore, the single-axis magnetic field sensor provided by the embodiment of the application can keep the resistance of each bridge arm unchanged under the external magnetic field perpendicular to the sensing shaft, a fixed resistor does not need to be prepared again, and the complexity of the preparation process of the single-axis magnetic field sensor can be reduced. In addition, the uniaxial magnetic field sensor can be obtained by only carrying out once patterning process and simple magnetic annealing process on the once deposited stacked layer, and the uniaxial magnetic field sensor is simple in process and low in manufacturing cost.

In the dual-axis magnetic field sensor provided by the embodiment of the application, under the action of an external magnetic field parallel to the second sensing axis, the second wheatstone bridge has a response, the resistance of each bridge arm of a first opposite bridge arm of the first wheatstone bridge is kept unchanged, and the resistance of two second reluctance modules on the same bridge arm of a second opposite bridge arm of the first wheatstone bridge generates opposite responses, so that the resistance of each bridge arm of the second opposite bridge arm is also kept unchanged, namely the first wheatstone bridge does not respond; under the action of an external magnetic field parallel to the first sensing shaft, the second Wheatstone bridge has no response, and the first Wheatstone bridge has a response. Therefore, the double-shaft magnetic field sensor provided by the embodiment of the application can sense the external magnetic field in each direction in a plane, the fixed resistor does not need to be prepared again, and the complexity of the preparation process of the double-shaft magnetic field sensor can be reduced. In addition, the double-shaft magnetic field sensor can be obtained by only carrying out once patterning process and simple magnetic annealing process on the once deposited stacked layer, and the double-shaft magnetic field sensor is simple in process and low in manufacturing cost.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic circuit diagram of a single-axis magnetic field sensor provided in an embodiment of the present application;

FIG. 2 is a graph of the resistance change of the MR module X under the influence of a magnetic field having a magnetic field direction parallel to the first sensing axis;

FIG. 3 is a graph of the resistance change of the MR block Y under the influence of a magnetic field having a magnetic field direction parallel to the first sensing axis;

FIG. 4 is a graph of the resistance variation of the MR module Z under the influence of a magnetic field having a magnetic field direction parallel to the first sensing axis;

FIG. 5 is a graph of the resistance change of the MR module X under the influence of a magnetic field having a direction perpendicular to the first sensing axis;

FIG. 6 is a graph of resistance change of the MR block Y under the influence of a magnetic field having a direction perpendicular to the first sensing axis;

FIG. 7 is a graph of the resistance change of the MR module Z under the influence of a magnetic field having a direction perpendicular to the first sensing axis;

fig. 8 is a graph illustrating a relationship between an angle between an external magnetic field direction and a first direction of a first sensing axis and a voltage signal output by a single-axis magnetic field sensor according to an embodiment of the present disclosure;

FIG. 9 is a schematic structural diagram of a single-axis magnetic field sensor according to yet another embodiment of the present application;

FIG. 10 is a schematic flow chart of a method for manufacturing a single-axis magnetic field sensor according to yet another embodiment of the present application;

FIG. 11 is a schematic circuit diagram of a dual-axis magnetic field sensor provided in accordance with an embodiment of the present application;

fig. 12 is a schematic flow chart of a method for manufacturing a two-axis magnetic field sensor according to another embodiment of the present application.

Detailed Description

In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.

In some of the flows described in the specification, claims, and above-described figures of the present application, a number of operations are included that occur in a particular order, which operations may be performed out of order or in parallel as they occur herein. The sequence numbers of the operations, e.g., 101, 102, etc., are used merely to distinguish between the various operations, and do not represent any order of execution per se. Additionally, the flows may include more or fewer operations, and the operations may be performed sequentially or in parallel. It should be noted that, the descriptions of "first", "second", etc. in this document are used for distinguishing different messages, devices, modules, etc., and do not represent a sequential order, nor limit the types of "first" and "second" to be different.

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Fig. 1 shows a schematic circuit diagram of a single-axis magnetic field sensor provided in an embodiment of the present application. As shown in fig. 1, the single-axis magnetic field sensor includes: a substrate (not shown) and a first Wheatstone bridge located on the substrate, wherein the first Wheatstone bridge comprises two first magnetic resistance module groups 1 and two second magnetic resistance module groups 2; the two first magnetoresistive module groups 1 are respectively located on a first opposite bridge arm of the first wheatstone bridge, and the magnetization directions of the reference layers of the first magnetoresistive modules 11 in the first magnetoresistive module groups 1 are both the same as the first direction of the first sensing axis of the uniaxial magnetic field sensor (i.e. the direction indicated by the arrow shown at the bottom of fig. 1); the two second magnetic resistance module groups 2 are respectively positioned on second opposite bridge arms of the first Wheatstone bridge, and the second magnetic resistance module groups 2 comprise two second magnetic resistance modules 21 which are connected in series; an angular bisector of a first included angle formed by the magnetization directions of the reference layers of the two second magnetoresistive modules 21 is parallel to the first sensing axis; wherein the first included angle is greater than 0 degrees and less than 180 degrees; the magnetization directions of the respective reference layers of the first magneto-resistive module 11 and the second magneto-resistive module 21 are perpendicular to the respective easy magnetization axes. It should be added that: in fig. 1, the directions of the arrows marked inside each of the first and second magneto-resistive modules 11 and 21 refer to the respective magnetization directions of the reference layers.

The substrate may be an insulating substrate or a semiconductor substrate, and in the case of a semiconductor substrate, an insulating layer needs to be formed on the surface of the semiconductor substrate. For example: the substrate is a silicon substrate, and a silicon oxide insulating layer is formed by performing thermal oxidation treatment on the surface of the silicon substrate. And then, depositing each layer of film of the magneto-resistance module on the insulating layer.

The first and second magneto-resistive modules each have a long axis (i.e., easy axis) and a short axis (i.e., hard axis) due to shape anisotropy. In particular, the first and second MR blocks can be etched to have a rectangular, hexagonal, or elliptical shape, which can facilitate the formation of a stable single domain in the free layer, such that the shape anisotropy is sufficiently strong that the magnetization direction of the free layer is along the long axis direction (i.e., along the easy axis direction) in the absence of an external magnetic field. That is, in the absence of an external magnetic field, the free layer magnetization direction of each of the first magnetoresistive module 11 and the second magnetoresistive module 21 forms an angle of 90 ° with the reference layer magnetization direction.

The uniaxial magnetic field sensor has a first sensing axis, indicating: the uniaxial magnetic field sensor has response under an external magnetic field which is not vertical to the first sensing shaft, namely, the voltage output under the external magnetic field which is not vertical to the first sensing shaft is not equal to the voltage output without the external magnetic field. When designing the resistance of each bridge arm in the single-axis magnetic field sensor provided by the embodiment of the present application, a person skilled in the art can set the resistance according to actual conditions, as long as it is ensured that the voltage output by the single-axis magnetic field sensor under the external magnetic field not perpendicular to the first sensing axis is not equal to the voltage output when no external magnetic field is present.

It should be noted that: the angle values of first included angles formed by the magnetization directions of the reference layers of the two second magneto-resistance modules in each second magneto-resistance module group are equal.

The working principle of the single-axis magnetic field sensor provided by the embodiment of the present application will be described with reference to fig. 1:

when the direction of the external magnetic field is the first direction of the first sensing axis, the magnetization directions of the free layers of the first magnetoresistive module 11 and the second magnetoresistive module 21 are both deflected to be consistent with the direction of the external magnetic field, that is, the included angle between the magnetization direction of the free layer of the first magnetoresistive module 11 and the magnetization direction of the reference layer is reduced from 90 degrees to 0 degree; the included angle between the magnetization direction of the free layer of the second magneto-resistance module and the magnetization direction of the reference layer is reduced from 90 DEG to(wherein, A is the angle value of the first included angle). The resistance of each bridge arm of the first opposite bridge arm is reduced, the resistance of the second opposite bridge arm is also reduced,but the first relative leg resistance and the second relative leg resistance do not change in magnitude. At this time, the first Wheatstone bridge outputs a voltage V_outAnd the first Wheatstone bridge output voltage V without external magnetic field_outDifferent. Therefore, the single-axis magnetic field sensor provided in fig. 1 of the present application is capable of inducing an external magnetic field in a first direction, which is the first sensing axis.

When the direction of the external magnetic field is a second direction (opposite to the first direction) of the first sensing shaft, the magnetization directions of the free layers of the first magnetic resistance module and the second magnetic resistance module are deflected to be consistent with the direction of the external magnetic field, namely, the included angle between the magnetization direction of the free layer of the first magnetic resistance module and the magnetization direction of the reference layer is increased to 180 degrees from 90 degrees; the included angle between the magnetization direction of the free layer of the second magneto-resistance module and the magnetization direction of the reference layer is increased from 90 DEG toThe resistance of each arm of the first opposite arm is increased, the resistance of the second opposite arm is also increased, but the resistance change amplitude of the first opposite arm is different from that of the second opposite arm. At this time, the first Wheatstone bridge outputs a voltage V_outAnd the first Wheatstone bridge output voltage V without external magnetic field_outDifferent. Therefore, the single-axis magnetic field sensor provided in fig. 1 of the present application is capable of inducing an external magnetic field in a second direction, which is the first sensing axis.

When the direction of the external magnetic field is perpendicular to the direction of the first sensing shaft, the magnetization direction of the free layer of the first reluctance module does not deflect, namely the resistance of each bridge arm in the first opposite bridge arm is unchanged; the magnetization directions of the free layers of the two second reluctance modules positioned on the same bridge arm in the second opposite bridge arm are deflected to be consistent with the direction of an external magnetic field, namely: the included angle between the magnetization direction of the free layer of one of the two second magnetoresistive modules on the same bridge arm and the magnetization direction of the reference layer is reduced from 90 DEG toFree layer magnetization direction and reference layer magnetization direction of another second magnetoresistive moduleIncreasing the included angle from 90 DEG toTherefore, the resistance changes of the two second reluctance modules on the same bridge arm are opposite, so that the resistance of each bridge arm in the second opposite bridge arm is unchanged. At this time, the output voltage Vout of the first wheatstone bridge is the same as the output voltage Vout of the first wheatstone bridge in the absence of an external magnetic field. Therefore, the single-axis magnetic field sensor provided by the application in fig. 1 does not induce an external magnetic field with a direction perpendicular to the first sensing axis.

As shown in fig. 1, the sensor provided in the embodiment of the present application has three kinds of magnetoresistive modules X, Y and Z (where a magnetoresistive module Y is a first magnetoresistive module, and a magnetoresistive module X and a magnetoresistive module Z are two second magnetoresistive modules connected in series to the same bridge arm). For example: taking the first included angle as 90 degrees as an example, the magnetization direction of the reference layer of the magnetoresistive module Y is the same as the first direction of the first sensing shaft, the magnetization directions of the reference layers of the magnetoresistive module X and the magnetoresistive module Z are 45 degrees with the first direction of the first sensing shaft 3, and the magnetization directions of the reference layers of the magnetoresistive module X and the magnetoresistive module Z are respectively located at two sides of the first sensing shaft.

FIGS. 2, 3, and 4 sequentially illustrate resistance change curves of the magnetoresistive module X, Y, Z under a magnetic field having a magnetic field direction parallel to the first sensing axis; fig. 5, 6, and 7 sequentially show the resistance change curves of the magnetoresistive module X, Y, Z under the action of the magnetic field with the magnetic field direction perpendicular to the first sensing axis. As can be seen from fig. 2, 3 and 4: the outputs of the magneto resistive module X and the magneto resistive module Z are smaller than the output of the magneto resistive module Y; as can be seen from fig. 5, 6, and 7: the reluctance module X and the reluctance module Z are in opposite output under an external magnetic field in the direction perpendicular to the first sensing shaft, namely under the action of the external magnetic field in the direction perpendicular to the first sensing shaft, the resistance changes of two second reluctance modules which are positioned on the same bridge arm and connected in series are opposite, and the resistance of the bridge arm is ensured to be unchanged. It should be noted that: a horizontal axis coordinate value greater than 0 indicates: the direction of the external magnetic field points to a second direction of the first sensing shaft; a horizontal axis coordinate value less than 0 indicates: the external magnetic field direction points in a first direction of the first sensing axis.

In the technical scheme provided by the embodiment of the application, under the action of an external magnetic field perpendicular to the first sensing shaft, the resistances of two second reluctance modules on the same bridge arm in a second opposite bridge arm generate opposite responses, so that the resistance of the bridge arm is kept unchanged. Therefore, the single-axis magnetic field sensor provided by the embodiment of the application can keep the resistance of each bridge arm unchanged under the external magnetic field perpendicular to the first sensing shaft, does not need to prepare a fixed resistor, and can reduce the complexity of the preparation process of the single-axis magnetic field sensor.

In an implementation, a third angle between the magnetization direction of the reference layer of the second magnetoresistive module 21 and the first direction of the first sensing axis is an obtuse angle.

In another implementation, as shown in fig. 1, a third angle between the magnetization direction of the reference layer of the second magnetoresistive module 21 and the first direction of the first sensing axis is an acute angle.

In practical applications, the first magnetoresistive module group 1 may include two first magnetoresistive modules 11 connected in series; the low resistance state of the first magnetoresistive module 11 is equal to the low resistance state of the second magnetoresistive module 21; the high resistance of the first magnetoresistive module 11 is equal to the high resistance of the second magnetoresistive module 21. Thus, in the absence of an external magnetic field, the first Wheatstone bridge is balanced and the output voltage is 0. Therefore, the calculation difficulty of subsequently calculating the direction of the external magnetic field can be reduced, and the measurement precision of the magnetic field sensor can be improved.

The resistances of two second magneto-resistive modules 21 connected in series in the second magneto-resistive module group are Ra and Rc respectively, the resistance of the first magneto-resistive module 11 is Rb, in the following formula, R is the resistance value of a low resistance state when the magnetization direction of the free layer is the same as that of the reference layer, Delta R is the resistance value difference between a high resistance state and a low resistance state, theta is the included angle between the external magnetic field direction and the first direction of the first sensing shaft, and Vcc is the input voltage:

it can be obtained that voltage Va at point a and voltage Vb at point b in fig. 1 are respectively:

the final sensor output voltage is:

for example: when the first included angle A is 90 degrees, the formula is shown in the specificationIs equal to Is equal to

As can be seen from the formula (6), when the direction of the external magnetic field is perpendicular to the first sensing axis, the output voltage is 0, i.e., no response occurs; when the direction of the external magnetic field is not perpendicular to the first sensing axis, the output voltage of the uniaxial magnetic field sensor is not 0, namely, the uniaxial magnetic field sensor has response.

FIG. 8 shows that Vcc is 1V,Is equal toThe relation between the voltage signal Vout and the angle theta is a cosine function curve, and the angle range from 0 degree to 180 degrees can be identified. If a single-axis magnetic field sensor orthogonal to the other sensing axis is integrated to form a double-axis magnetic field sensor, 360-degree angle identification can be realized. And theta is an included angle between the direction of the external magnetic field and the first direction of the first sensing shaft.

In an implementation, as shown in fig. 9, the first magnetoresistance module 11 is formed by connecting Q first magnetoresistance units in series; the second reluctance module 21 is formed by connecting Q second reluctance units in series; the first magnetoresistive unit and the second magnetoresistive unit are the same in shape; the easy magnetization axes of the Q first magnetic resistance units are parallel to each other; the easy magnetization axes of the Q second magnetic resistance units are parallel to each other; wherein Q is a positive integer. This ensures that: the low resistance state of the first magnetoresistive module 11 is equal to the low resistance state of the second magnetoresistive module 21; the high-resistance state resistance value of the first reluctance module 11 is equal to the high-resistance state resistance value of the second reluctance module 21, so that the resistance matching of each bridge arm can be realized, and the measurement precision is improved. Furthermore, the larger the number of magneto-resistive elements in each leg, the less noise the bridge will have, because the uncorrelated random behavior of each magneto-resistive element is averaged out. Also shown in fig. 9 are four electrodes 4.

In order to combine the following two aspects, the first included angle a is set to be greater than 80 ° and less than 100 °. In a preferred embodiment, the first included angle a is 90 °.

In the first aspect, the larger the output voltage value of the uniaxial magnetic field sensorThe higher the sensor sensitivity, the higher the equation (6) takes cos θ as 1 (i.e., the first direction along the first sensing axis in the external magnetic field direction),the smaller the value of (i.e., the larger the value of A), the larger the value of Vout; in a second aspect, the smaller the value of a, the easier it is to deflect the reference layer magnetization direction of the second magneto-resistive module to the short axis direction of the magneto-resistive module due to shape anisotropy and demagnetizing field effects after magnetic annealing in the first direction of the first sense axis, because the smaller the value of a, the smaller the angle required to deflect the reference layer magnetization direction in the first direction of the first sense axis to the short axis direction after annealing.

FIG. 11 shows a schematic circuit diagram of a dual-axis magnetic field sensor provided in accordance with yet another embodiment of the present application. As shown in fig. 11, the two-axis magnetic field sensor includes: a substrate (not shown); a first Wheatstone bridge with a first sensing axis and a second Wheatstone bridge with a second sensing axis on the substrate, wherein the first sensing axis and the second sensing axis are perpendicular to each other; the first Wheatstone bridge comprises two first magnetic resistance module groups 1 and two second magnetic resistance module groups 2; the two first magnetoresistive module groups 1 are respectively located on a first opposite bridge arm of the first wheatstone bridge, and the magnetization directions of the reference layers of the first magnetoresistive modules 11 in the first magnetoresistive module groups 1 are both the same as the first direction of the first sensing axis of the uniaxial magnetic field sensor (i.e. the direction indicated by the arrow shown at the bottom of fig. 11); the two second magnetic resistance module groups 2 are respectively positioned on second opposite bridge arms of the first Wheatstone bridge, and the second magnetic resistance module groups 2 comprise two second magnetic resistance modules 21 which are connected in series; an angular bisector of a first included angle formed by the magnetization directions of the reference layers of the two second magnetoresistive modules 21 is parallel to the first sensing axis; wherein the first included angle is greater than 0 degrees and less than 180 degrees; the second wheatstone bridge comprises four third reluctance modules 41 respectively positioned on each bridge arm of the second wheatstone bridge; an angular bisector of a second included angle formed by the magnetization directions of the reference layers of the two third magnetic resistance modules 41 respectively positioned on the adjacent bridge arms of the second wheatstone bridge is parallel to the first sensing axis; a second included angle formed by the magnetization directions of the reference layers of the two third magneto-resistive modules 41 respectively positioned on the adjacent bridge arms of the second wheatstone bridge is larger than 0 degree and smaller than 180 degrees; the magnetization directions of the reference layers of the first magneto-resistive module 11, the second magneto-resistive module 21, and the third magneto-resistive module 41 are perpendicular to the easy magnetization axes thereof.

It should be added that: in fig. 1, the directions of the arrows marked inside each of the first, second, and third magneto-resistive modules 11, 21, and 41 refer to the respective magnetization directions of the reference layers.

The first, second, and third magneto-resistive modules 11, 21, and 41 each have a long axis (i.e., easy axis) and a short axis (i.e., hard axis) due to shape anisotropy. In particular, the first, second, and third magneto-resistive modules 11, 21, and 41 may be etched to have a rectangular, hexagonal, or elliptical shape, which may facilitate the formation of a stable single magnetic domain in the free layer, such that the shape anisotropy is strong enough to cause the magnetization direction of the free layer to be along the long axis direction (i.e., along the easy axis direction) in the absence of an external magnetic field.

The working principle of the dual-axis magnetic field sensor provided by the embodiment of the present application will be described with reference to fig. 11:

when the direction of the external magnetic field is the first direction of the first sensing shaft, the magnetization directions of the free layers of the third magneto-resistive modules on the second Wheatstone bridge are all deflected to be consistent with the direction of the external magnetic field, namely, the included angles between the magnetization directions of the free layers of all the third magneto-resistive modules on the second Wheatstone bridge and the magnetization direction of the reference layer are changed from 90 DEG toIt can be seen that the resistance changes of the two opposite arms of the second wheatstone bridge are equal, and therefore, the second wheatstone bridge does not respond to the first direction, which is the direction of the first sensing axis. From the above analysis of the operating principle of the single-axis magnetic field sensor, it can be known that: the first Wheatstone bridge is capable of responding to an external magnetic field having a first direction of the first sensing axis.

When the direction of the external magnetic field is the second direction (opposite to the first direction) of the first sensing shaft, the magnetization directions of the free layers of the third magneto-resistive modules on the second Wheatstone bridge are all deflected to be consistent with the direction of the external magnetic field, namely, the included angles between the magnetization directions of the free layers of all the third magneto-resistive modules on the second Wheatstone bridge and the magnetization direction of the reference layer are changed from 90 DEG toIt can be seen that the resistance changes of the two opposite arms of the second wheatstone bridge are equal, and therefore, the second wheatstone bridge does not respond to the first direction, which is the direction of the first sensing axis. From the above analysis of the operating principle of the single-axis magnetic field sensor, it can be known that: the first Wheatstone bridge is capable of responding to an external magnetic field oriented in a second direction of the first sensing axis.

When the direction of the external magnetic field is parallel to the second sensing shaft, the magnetization direction of the free layer of the third magneto-resistive module on the second Wheatstone bridge is deflected to be consistent with the direction of the external magnetic field, namely the included angle between the magnetization direction of the free layer of the third magneto-resistive module on each bridge arm of the opposite bridge arms of the second Wheatstone bridge and the magnetization direction of the reference layer is changed from 90 DEG toThe included angle between the magnetization direction of the free layer of the third magneto-resistive module on each of the other opposite bridge arms of the second Wheatstone bridge and the magnetization direction of the reference layer is changed from 90 DEG toIt can be seen that the bridge arm resistances of the two opposite bridge arms on the second wheatstone bridge change oppositely, and therefore the second wheatstone bridge is capable of responding to an external magnetic field having a direction parallel to the second sensing axis. From the above analysis of the operating principle of the single-axis magnetic field sensor, it can be known that: the first wheatstone bridge is not responsive to an external magnetic field having a direction parallel to the second sensing axis.

In the dual-axis magnetic field sensor provided by the embodiment of the application, under the action of an external magnetic field parallel to the second sensing axis, the second wheatstone bridge has a response, the resistance of each bridge arm of a first opposite bridge arm of the first wheatstone bridge is kept unchanged, and the resistance of two second reluctance modules on the same bridge arm of a second opposite bridge arm of the first wheatstone bridge generates opposite responses, so that the resistance of each bridge arm of the second opposite bridge arm is also kept unchanged, namely the first wheatstone bridge does not respond; under the action of an external magnetic field parallel to the first sensing shaft, the second Wheatstone bridge has no response, and the first Wheatstone bridge has a response. Therefore, the double-shaft magnetic field sensor provided by the embodiment of the application can sense the external magnetic field in each direction in a plane, does not need to prepare a fixed resistor, and can reduce the complexity of the preparation process of the double-shaft magnetic field sensor.

Further, the first included angle is greater than 80 ° and less than 100 °. Specifically, the method comprises the following steps: the first included angle may be taken to be 90 °.

Further, the first magnetoresistive module group 1 includes two first magnetoresistive modules 11 connected in series; the low resistance state of the first magnetoresistive module 11 is equal to the low resistance state of the second magnetoresistive module 21; the high resistance of the first magnetoresistive module 11 is equal to the high resistance of the second magnetoresistive module 21.

Further, the first reluctance module 11 is formed by connecting Q first reluctance units in series; the second reluctance module 21 is formed by connecting Q second reluctance units in series; the first magnetoresistive unit and the second magnetoresistive unit are the same in shape; the easy magnetization axes of the Q first magnetic resistance units are parallel to each other; the easy magnetization axes of the Q second magnetic resistance units are parallel to each other; wherein Q is a positive integer.

Further, the third magnetoresistance module 41 may also be formed by connecting N third magnetoresistance units in series, where easy magnetization axes of the N third magnetoresistance units are parallel to each other, and N is a positive integer. The greater the number of magneto-resistive elements in each leg, the less noise the bridge will have, because the random, mutually uncorrelated behavior of each magneto-resistive element is averaged out.

Further, a third included angle between the magnetization direction of the reference layer of the second magnetoresistive module 21 and the first direction of the first sensing axis is an acute angle.

Further, the angle value of the second included angle may be equal to the angle value of the first included angle.

It should be noted that the specific structure and the beneficial effects of the first wheatstone bridge can be referred to the corresponding contents in each embodiment of the single-axis magnetic field sensor, and are not described herein again.

The present application also provides an electronic device comprising the single-axis magnetic field sensor in the above embodiments. Including but not limited to cell phones, smart watches, MP4, head mounted display devices, game pads, and the like.

The present application also provides an electronic device including the two-axis magnetic field sensor in each of the above embodiments. Including but not limited to cell phones, smart watches, MP4, head mounted display devices, game pads, and the like.

Fig. 10 is a schematic flow chart illustrating a method for manufacturing a uniaxial magnetic field sensor according to still another embodiment of the present application. As shown in fig. 10, the preparation method includes:

1101. several layers of thin films are deposited in sequence on a substrate to obtain a stack.

1102. And carrying out imaging etching on the stacked layer to form two first stacked block groups and two second stacked block groups.

1103. And preparing a conducting wire on the substrate, wherein the conducting wire is connected with the two first stacking block groups and the two second stacking block groups to form a first bridge structure.

1104. And annealing in a magnetic field, and cooling after removing the magnetic field to convert the first stacked block set into a first magnetic resistance module set, convert the second stacked block set into a second magnetic resistance module set, and convert the first bridge structure into a first Wheatstone bridge to obtain the uniaxial magnetic field sensor.

As shown in fig. 1, two first magnetoresistive module groups 1 are respectively located on a first opposite bridge arm of the first wheatstone bridge, and the magnetization direction of the reference layer of the first magnetoresistive module 11 in the first magnetoresistive module group 1 is the same as the first direction of the first sensing axis of the uniaxial magnetic field sensor (i.e. the direction indicated by the arrow shown at the bottom of fig. 1); the two groups of the second magnetic resistance modules 2 are respectively positioned on the second opposite bridge arms of the first Wheatstone bridge, and the second magnetic resistance module group 2 comprises two second magnetic resistance modules 21 which are connected in series; an angular bisector of a first included angle formed by the magnetization directions of the reference layers of the two second magnetoresistive modules 21 is parallel to the first sensing axis; wherein the first included angle is greater than 0 degrees and less than 180 degrees; the magnetization directions of the respective reference layers of the first magneto-resistive module 11 and the second magneto-resistive module 21 are perpendicular to the respective easy magnetization axes.

The easy magnetization axis of each of the first and second magnetoresistive modules is the long axis of each magnetoresistive module.

In the above step 1101, each layer of thin film may be prepared on the substrate by magnetron sputtering, atomic layer deposition, pulsed laser deposition, molecular beam epitaxy, or electron beam evaporation, to obtain a stacked layer. In general, the stack layer may include a seed layer, an antiferromagnetic pinning layer, a reference layer, a nonmagnetic interlayer, an induced (i.e., free) layer, and a capping layer, which are stacked in this order from bottom to top. The specific structure and specific material of each layer may be designed according to actual needs, and the present invention is not particularly limited thereto. For example: the antiferromagnetic pinning layer is mainly made of IrMn, PtMn and FeMn; a reference layer, the main material of which is CoFe; a nonmagnetic spacer layer of material predominantly Cu; and the main material of the free layer is CoFe.

In the step 1102, the specific shapes of the first stacking block set and the second stacking block set may be designed according to actual needs, which is not limited in this embodiment. The first stacked block in the first stacked block group and the second stacked block in the second stacked block group each have shape anisotropy, for example: the shape anisotropy is as follows: rectangular, oval, etc.

The film stack layer may be etched by Inductively Coupled Plasma (ICP), reactive-ion etching (RIE) or ion beam etching process to obtain two first stack blocks and two second stack blocks.

In the step 1103, the conductive wire may be prepared by thermal evaporation, magnetron sputtering, or other processes. In specific implementation, a mask plate containing a wire pattern can be prepared in advance, and a metal material is deposited by thermal evaporation or magnetron sputtering through the mask plate to prepare the wire. The two first stacking block groups and the two second stacking block groups are connected through conducting wires to form a first bridge structure.

In the step 1104, the heating process is performed in the magnetic field, and then the magnetic field is removed and the product is cooled to obtain the final product. After heating treatment in a magnetic field, the magnetization directions of the reference layers of the first stack block in the first stack block group and the second stack block in the second stack block group are both along the magnetic field direction of the magnetic field, and in the process of removing the magnetic field and cooling, the magnetization direction of the reference layer of the first stack block deviates from the magnetic field direction of the magnetic field due to shape anisotropy and demagnetizing field action, deflects to the short axis direction and is fixed, so that the conversion from the first stack block to the first magnetoresistive module is completed, that is, the conversion from the first stack block to the first magnetoresistive module is completed; and/or the magnetization direction of the reference layer of the second stacked block deviates from the magnetic field direction of the magnetic field due to the shape anisotropy and the action of a demagnetizing field, deflects to the short axis direction of the magnetic field and is fixed, so that the conversion from the second stacked block to the second magnetoresistive module, namely the conversion from the second stacked block to the second magnetoresistive module, is completed.

In order to obtain the uniaxial magnetic field sensor shown in FIG. 1, the angle value B of the angle formed by the direction of the applied magnetic field and the first direction of the first sensing axis during annealing needs to be smaller than

In an implementable version, the magnetic field direction of the magnetic field is the same as the first direction of the sense axis. Thus, after the heating treatment in the magnetic field is completed, when the magnetic field is removed, the magnetization direction of the reference layer of the first stacked block is along the short axis direction, so that the magnetization direction of the reference layer of the first stacked block is not deflected during the cooling process, that is, after the heating treatment in the magnetic field is completed, the conversion of the first stacked block to the first magnetoresistive module is completed. After the heating treatment in the magnetic field is completed, when the magnetic field is removed, the magnetization direction of the reference layer of the second stacked block is along the magnetic field direction and not along the short axis direction, so that in the cooling process, the magnetization direction of the reference layer of the second stacked block deviates from the magnetic field direction of the magnetic field due to the shape anisotropy and the action of a demagnetizing field, deflects to the short axis direction and is fixed, and thus the conversion of the second stacked block to the second magnetoresistive module is completed. Note: during cooling, the magnetization direction of the reference layer of the second stack will be deflected to the short axis direction by the minimum deflection angle under the shape anisotropy and the demagnetizing field.

In general, the magnetic field strength used for annealing needs to be greater than the antiferromagnetic pinning magnetic field strength of the stacked layers and the annealing temperature is about the antiferromagnetic pinning layer blocking temperature T of the stacked layers to achieve biasing of the magnetization direction of the reference layer. Specifically, the annealing temperature range is [ T-50 ℃, T +50 ℃.

The substrate may be an insulating substrate or a semiconductor substrate, and when the substrate is a semiconductor substrate, the manufacturing method further includes: before depositing several films on the substrate, an insulating layer is formed on the surface of the semiconductor substrate. For example: the substrate is a silicon substrate, and a silicon oxide insulating layer is formed by performing thermal oxidation treatment on the surface of the silicon substrate. Then, several layers of thin films are deposited on the insulating layer.

In the technical scheme provided by the embodiment of the application, under the action of an external magnetic field perpendicular to the sensing shaft, the resistances of two second reluctance modules on the same bridge arm in a second opposite bridge arm generate opposite responses, so that the resistance of the bridge arm is kept unchanged. Therefore, the single-axis magnetic field sensor provided by the embodiment of the application can keep the resistance of each bridge arm unchanged under the external magnetic field perpendicular to the sensing shaft, does not need to prepare a fixed resistor, and can reduce the complexity of the preparation process of the single-axis magnetic field sensor. In addition, the uniaxial magnetic field sensor can be obtained by only carrying out once patterning process and simple magnetic annealing process on the once deposited stacked layer, and the uniaxial magnetic field sensor is simple in process and low in manufacturing cost.

Further, the first included angle is 90 °.

Further, the first magnetoresistive module group comprises two first magnetoresistive modules connected in series; the low resistance state of the first magnetic resistance module is equal to the low resistance state of the second magnetic resistance module; the high-resistance-state resistance value of the first magnetic resistance module is equal to the high-resistance-state resistance value of the second magnetic resistance module.

In an implementation scheme, the first magnetic resistance module is formed by connecting Q first magnetic resistance units in series; the second magnetic resistance module is formed by connecting Q second magnetic resistance units in series; the first magnetoresistive unit and the second magnetoresistive unit are the same in shape; the easy magnetization axes of the Q first magnetic resistance units are parallel to each other; the easy magnetization axes of the Q second magnetic resistance units are parallel to each other; wherein Q is a positive integer.

Furthermore, a third included angle formed between the magnetization direction of the reference layer of the second magnetoresistive module and the first direction of the first sensing axis is an acute angle.

The specific structure and the working principle of the uniaxial magnetic field sensor prepared by the preparation method provided by this embodiment can be referred to the above related embodiments, and are not described herein again.

Fig. 12 is a schematic flow chart illustrating a method for manufacturing a two-axis magnetic field sensor according to another embodiment of the present application. As shown in fig. 12, the preparation method includes:

1201. several layers of thin films are deposited in sequence on a substrate to obtain a stack.

1202. And carrying out imaging etching on the stacked layer to form two first stacked block groups, two second stacked block groups and four third stacked blocks.

1203. Preparing a conducting wire on the substrate, wherein the conducting wire is connected with the two first stacking block groups and the two second stacking block groups to form a first bridge structure; the wires connect the four third stacked blocks to form a second bridge structure.

1204. Annealing in a magnetic field, and cooling after removing the magnetic field to convert the first stacked block set into a first magnetoresistive module set, the second stacked block set into a second magnetoresistive module set, the third stacked block set into a third magnetoresistive module, the first bridge structure into a first Wheatstone bridge, and the second bridge structure into a second Wheatstone bridge, so as to obtain the biaxial magnetic field sensor.

Wherein, as shown in fig. 11, the first wheatstone bridge has a first sensing axis and the second wheatstone bridge has a second sensing axis; wherein the first sensing axis and the second sensing axis are perpendicular to each other; the first Wheatstone bridge comprises two first magnetic resistance module groups 1 and two second magnetic resistance module groups 2; the two first magnetoresistive module groups 1 are respectively located on a first opposite bridge arm of the first wheatstone bridge, and the magnetization directions of the reference layers of the first magnetoresistive modules 11 in the first magnetoresistive module groups 1 are both the same as the first direction of the first sensing shaft of the uniaxial magnetic field sensor (i.e. the direction indicated by an arrow shown at the bottom of fig. 11); the two second magnetic resistance module groups 2 are respectively positioned on second opposite bridge arms of the first Wheatstone bridge, and the second magnetic resistance module groups 2 comprise two second magnetic resistance modules 21 which are connected in series; an angular bisector of a first included angle formed by the magnetization directions of the reference layers of the two second magnetoresistive modules 21 is parallel to the first sensing axis; wherein the first included angle is greater than 0 degrees and less than 180 degrees; the four third magnetoresistive modules 41 are respectively located on each bridge arm of the second wheatstone bridge; an angular bisector of a second included angle formed by the magnetization directions of the reference layers of the two third magnetic resistance modules 41 respectively positioned on the adjacent bridge arms of the second wheatstone bridge is parallel to the first sensing axis; a second included angle formed by the magnetization directions of the reference layers of the two third magneto-resistive modules 41 respectively positioned on the adjacent bridge arms of the second wheatstone bridge is larger than 0 degree and smaller than 180 degrees; the magnetization directions of the reference layers of the first magneto-resistive module 11, the second magneto-resistive module 21, and the third magneto-resistive module 41 are perpendicular to the easy magnetization axes thereof.

The easy magnetization axes of the first magneto-resistive module 11, the second magneto-resistive module 21, and the third magneto-resistive module 41 are long axes of the respective magneto-resistive modules.

The above step 1201 can refer to corresponding contents in the above embodiments, and details are not repeated herein.

In the step 1202, the specific shapes of the first stacking block group, the second stacking block group and the second stacking block group can be designed according to actual needs, which is not limited in this embodiment. The first stacked block in the first stacked block group and the second stacked block in the second stacked block group each have shape anisotropy, for example: the shape anisotropy is as follows: rectangular, oval, etc.

The film stack layer may be etched by Inductively Coupled Plasma (ICP), reactive-ion etching (RIE) or ion beam etching process to obtain two first stack blocks, two second stack blocks and four third stack blocks.

In step 1203, the conductive lines may be prepared by thermal evaporation, magnetron sputtering, or the like. In specific implementation, a mask plate containing a wire pattern can be prepared in advance, and a metal material is deposited by thermal evaporation or magnetron sputtering through the mask plate to prepare the wire. The two first stacking block groups and the two second stacking block groups are connected through conducting wires to form a first bridge structure. The four third stacked blocks are connected by wires to form a second bridge structure.

In the step 1204, the heating process is performed in the magnetic field, and then the magnetic field is removed and the product is cooled to obtain the final product. After heating treatment in a magnetic field, the magnetization directions of the reference layers of the first stacked block, the second stacked block and the third stacked block are all along the magnetic field direction of the magnetic field, and in the process of removing the magnetic field and cooling, the magnetization direction of the reference layer of the first stacked block deviates from the magnetic field direction of the magnetic field due to shape anisotropy and the action of a demagnetizing field, deflects to the short axis direction and is fixed, so that the conversion from the first stacked block to the first magnetoresistive module is completed, namely the conversion from the first stacked block to the first magnetoresistive module is completed; and/or the magnetization direction of the reference layer of the second stacked block deviates from the magnetic field direction of the magnetic field due to the shape anisotropy and the action of a demagnetizing field, deflects to the short axis direction of the magnetic field and is fixed, so that the conversion from the second stacked block to the second magnetoresistive module is completed, namely the conversion from the second stacked block to the second magnetoresistive module is completed; and/or the magnetization direction of the reference layer of the third stacked block deviates from the magnetic field direction of the magnetic field due to the shape anisotropy and the action of a demagnetizing field, deflects to the short axis direction of the magnetic field and is fixed, so that the conversion from the third stacked block to the third magnetoresistive module is completed, namely the conversion from the third stacked block to the third magnetoresistive module is completed.

In order to obtain the two-axis magnetic field sensor shown in FIG. 11, the angle B between the direction of the applied magnetic field and the first direction of the first sensing axis 3 during annealing needs to be smaller than

In an implementable version, the magnetic field direction of the magnetic field is the same as the first direction of the first sense axis. Thus, after the heating treatment in the magnetic field is completed, when the magnetic field is removed, the magnetization direction of the reference layer of the first stacked block is along the short axis direction, so that the magnetization direction of the reference layer of the first stacked block is not deflected during the cooling process, that is, after the heating treatment in the magnetic field is completed, the conversion of the first stacked block to the first magnetoresistive module is completed. After the heating treatment in the magnetic field is completed, when the magnetic field is removed, the magnetization directions of the reference layers of the second stacked block and the third stacked block are along the magnetic field direction and not along the short axis direction, so that the magnetization directions of the reference layers of the second stacked block and the third stacked block deviate from the magnetic field direction of the magnetic field due to shape anisotropy and demagnetizing field action in the cooling process, and the magnetization directions of the reference layers of the second stacked block and the third stacked block are deflected to the respective short axis directions and fixed, so that the conversion from the second stacked block to the second magnetoresistive module and the conversion from the third stacked block to the third magnetoresistive module are realized. Note: during cooling, the magnetization directions of the reference layers of the second and third stacked blocks will be deflected to the short axis direction by the minimum deflection angle under the effect of the shape anisotropy and the demagnetizing field.

In the dual-axis magnetic field sensor provided by the embodiment of the application, under the action of an external magnetic field parallel to the second sensing axis, the second wheatstone bridge has a response, the resistance of each bridge arm of a first opposite bridge arm of the first wheatstone bridge is kept unchanged, and the resistance of two second reluctance modules on the same bridge arm of a second opposite bridge arm of the first wheatstone bridge generates opposite responses, so that the resistance of each bridge arm of the second opposite bridge arm is also kept unchanged, namely the first wheatstone bridge does not respond; under the action of an external magnetic field parallel to the first sensing shaft, the second Wheatstone bridge has no response, and the first Wheatstone bridge has a response. Therefore, the double-shaft magnetic field sensor provided by the embodiment of the application can sense the external magnetic field in each direction in a plane, does not need to prepare a fixed resistor, and can reduce the complexity of the preparation process of the double-shaft magnetic field sensor. In addition, the double-shaft magnetic field sensor can be obtained by only carrying out once patterning process and simple magnetic annealing process on the once deposited stacked layer, and the double-shaft magnetic field sensor is simple in process and low in manufacturing cost.

Further, the included angle is greater than 80 ° and less than 100 °. Specifically, the method comprises the following steps: the included angle may be taken to be 90 °.

Furthermore, the first magnetic resistance module is formed by connecting Q first magnetic resistance units in series; the second magnetic resistance module is formed by connecting Q second magnetic resistance units in series; the first magnetoresistive unit and the second magnetoresistive unit are the same in shape; the easy magnetization axes of the Q first magnetic resistance units are parallel to each other; the easy magnetization axes of the Q second magnetic resistance units are parallel to each other; wherein Q is a positive integer.

Furthermore, the third magnetoresistive module can also be formed by connecting N third magnetoresistive units in series, wherein the easy magnetization axes of the N third magnetoresistive units are parallel to each other, and N is a positive integer. The greater the number of magneto-resistive elements in each leg, the less noise the bridge will have, because the random, mutually uncorrelated behavior of each magneto-resistive element is averaged out.

Further, the angle value of the second angle may be equal to the angle value of the first angle.

The specific structure and the working principle of the biaxial magnetic field sensor prepared by the preparation method provided by this embodiment can be referred to the related embodiments, and are not described herein again.

Compared with the prior art, the single-axis and double-axis magnetic field sensor and the preparation method thereof provided by the embodiment of the application have the following advantages:

1) the half Wheatstone bridge unipolar magnetic field sensor that this application embodiment provided can use once graphical technology to realize, and the process step is simple, and the cost is lower.

2) The four bridge arms of the sensor are manufactured by using the same film (namely, stacked layers), so that accurate bridge arm resistance matching can be realized, and the bias voltage is reduced.

3) The half wheatstone bridge single-axis magnetic field sensor and the full wheatstone bridge (i.e. the second wheatstone bridge) can be closely placed on the same substrate through the same image process, and the double-axis magnetic field sensor can be manufactured through the same annealing process.

4) Compatible with CMOS technology, and can be widely integrated on various chips.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims

1. A single-axis magnetic field sensor, comprising: the magnetic resonance imaging device comprises a substrate and a first Wheatstone bridge positioned on the substrate, wherein the first Wheatstone bridge comprises two first magnetic resistance module groups and two second magnetic resistance module groups; wherein,

2. The single-axis magnetic field sensor of claim 1, wherein the first included angle is greater than 80 ° and less than 100 °.

3. The single-axis magnetic field sensor of claim 1, wherein the first included angle is 90 °.

4. The uniaxial magnetic field sensor according to any one of claims 1 to 3,

the first magnetic resistance module group comprises two first magnetic resistance modules which are connected in series;

5. The uniaxial magnetic field sensor of claim 4, wherein the first magnetoresistive module is formed by connecting Q first magnetoresistive units in series; the second magnetic resistance module is formed by connecting Q second magnetic resistance units in series; the first magnetoresistive unit and the second magnetoresistive unit are the same in shape;

wherein Q is a positive integer.

6. The uniaxial magnetic field sensor of any one of claims 1 to 3, wherein a third angle formed by the magnetization direction of the reference layer of the second magnetoresistive module and the first direction of the first sensing axis is an acute angle.

7. A dual-axis magnetic field sensor, comprising: a substrate;

8. An electronic device, characterized in that it comprises a single-axis magnetic field sensor according to any of the preceding claims 1 to 6.

9. An electronic device comprising the two-axis magnetic field sensor according to claim 7.

10. A method of making a single-axis magnetic field sensor, comprising:

11. The method of claim 10, wherein the magnetic field has a magnetic field direction that is the same as the first direction of the first axis of sensitivity.

12. A method for preparing a biaxial magnetic field sensor is characterized by comprising the following steps:

13. The method of claim 12, wherein the magnetic field has a magnetic field direction that is the same as the first direction of the first axis of sensitivity.