Magnetoresistive sensor and optimization method therefor

Abstract

The present application relates to the technical field of sensors, and discloses a magnetoresistive sensor and an optimization method therefor. The optimization method for the magnetoresistive sensor of the present application comprises: establishing a simulation model of the magnetoresistive sensor, wherein the magnetoresistive sensor comprises four magnetoresistive elements forming a Wheatstone bridge; acquiring a fixed parameter value; on the basis of a sensitivity calculation formula S=f(Rmr,Rb,Rct,), obtaining a temperature-sensitivity curve of the magnetoresistive sensor corresponding to simulation values of design parameters in a preset temperature interval; calculating a temperature coefficient of sensitivity of the magnetoresistive sensor corresponding to the plurality of simulation values of the design parameters, and calculating the change rate of the temperature coefficient of sensitivity; and comparing the change rate of the temperature coefficient of sensitivity with a change rate threshold, and when the change rate is less than or equal to the change rate threshold, taking the simulation values corresponding to the design parameters as optimization values of the design parameters. According to the magnetoresistive sensor and the optimization method therefor provided by the present application, the nonlinearity of the temperature sensitivity can be reduced by adjusting the structure of the magnetoresistive sensor.

Description

A magnetoresistive sensor and its optimization method

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application number 2023108981391, filed with the Chinese Patent Office on July 20, 2023, entitled “A Magnetoresistive Sensor and Its Optimization Method,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of sensor technology, and in particular to a magnetoresistive sensor and an optimization method thereof. Background Art

[0004] Magnetoresistive sensors, based on the magnetoresistive effect of magnetic materials, offer high sensitivity and low power consumption, making them widely used in electronic compasses, position detection, and current detection. With the advancement of magnetic field detection technology, many different types of magnetoresistive sensors have emerged, including anisotropic magnetoresistive sensors, giant magnetoresistive sensors, and tunnel magnetoresistive sensors.

[0005] The sensitivity of magnetoresistive sensors changes with temperature, affecting detection accuracy. This sensitivity change can be expressed using the temperature coefficient of sensitivity (TCS). Existing methods for improving sensor temperature characteristics primarily involve temperature compensation in back-end processing circuits. Magnetoresistive sensors often exhibit nonlinear temperature sensitivity, meaning the TCS varies with temperature, complicating the design of back-end compensation circuits.

[0006] Summary of the Invention

[0007] The purpose of the present application is to provide a magnetoresistive sensor and an optimization method thereof, which can reduce the nonlinearity of temperature sensitivity by adjusting the structure of the magnetoresistive sensor itself, thereby facilitating the setting of a back-end compensation circuit.

[0008] On the one hand, an embodiment of the present application provides an optimization method for a magnetoresistive sensor, comprising: establishing a simulation model of the magnetoresistive sensor, the magnetoresistive sensor comprising four magnetoresistive elements constituting a Wheatstone bridge, the magnetoresistive elements comprising a substrate, and a magnetic layer, a protective layer, and an insulating layer sequentially arranged on the substrate, a connecting through-hole being provided on the insulating layer, a metal electrode being provided in the connecting through-hole so as to allow the metal electrode to contact the protective layer; obtaining fixed parameter values, selecting multiple simulation values ​​of each design parameter within a preset range of each design parameter, and measuring each resistivity at multiple temperature points within a preset temperature range, and calculating the resistance value R of the magnetic layer respectively. mr , the resistance value of the protective layer Rb And the contact resistance value R between the metal electrode and the protective layer ct , where the resistance value of the magnetic layer R mr =(S1,D1,ρ mr ), the resistance value of the protective layer R b =(S2,D2,ρ b ), the contact resistance value R between the metal electrode and the protective layer ct =(S3,D3,ρ ct ); S1 is the first design parameter, D1 is the first fixed parameter, ρ mr is the resistivity of the magnetic layer, S2 is the second design parameter, D2 is the second fixed parameter, ρ b is the resistivity of the protective layer, S3 is the third design parameter, D3 is the third fixed parameter, ρ ct is the contact resistivity; D1 is one or more of the material, length, width and thickness of the magnetic layer, and the rest is S1; D2 is one or more of the material, length, width and thickness of the protective layer, and the rest is S2; D3 is one or more of the material of the protective layer, the material of the metal electrode, and the contact area, and the rest is S3; According to the sensitivity calculation formula S=f(R mr ,R b ,R ct ,) Obtain the temperature-sensitivity curve of the magnetoresistive sensor corresponding to each simulation value of each design parameter in the preset temperature range; According to the temperature-sensitivity curve, calculate the temperature sensitivity coefficient of the magnetoresistive sensor for multiple simulation values ​​of each design parameter respectively, and calculate the change rate of the temperature sensitivity coefficient; Compare the change rate of the temperature sensitivity coefficient with the change rate threshold, and the simulation value corresponding to each design parameter when it is less than or equal to the change rate threshold is used as the optimized value of the design parameter.

[0009] As an implementable method, according to the sensitivity calculation formula S=f(R mr ,R b ,R ct ,) Obtaining the temperature-sensitivity curve of the magnetoresistive sensor corresponding to each simulation value of each design parameter in the temperature preset range, including: calculating the sensitivity of the magnetoresistive sensor at each simulation value according to the relationship (1.1),

[0010] Where S is the sensitivity of the magnetoresistive sensor, V out is the maximum differential signal output of the magnetoresistive sensor under the saturation magnetic field Hs and unit power supply voltage; H S is the saturation magnetic field; R tot is the total resistance of the magnetoresistive element, R tot_max is the maximum value of the total resistance of the magnetoresistive element, R tot_minis the minimum value of the total resistance of the magnetoresistive element; and a plurality of temperature-sensitivity curves are formed according to the calculated sensitivities corresponding to a plurality of temperature points within the preset temperature range.

[0011] As an implementable method, according to the temperature-sensitivity curve, respectively calculating the temperature sensitivity coefficient of the magnetoresistive sensor for multiple simulation values ​​of each design parameter, and calculating the rate of change of the temperature sensitivity coefficient includes: calculating the temperature sensitivity coefficient of the magnetoresistive sensor for each simulation value of each design parameter according to the relationship (1.2),

[0012] Where TCS is the temperature sensitivity coefficient of the magnetoresistive sensor, is the sensitivity of the magnetoresistive sensor at temperature T1, is the sensitivity of the magnetoresistive sensor at the reference temperature T0; calculate the change rate of the temperature sensitivity coefficient under each simulation value of each design parameter.

[0013] As an implementable method, the sensitivity of the magnetoresistive sensor at each simulation value is calculated according to the relationship (1.1), including: determining the material of the magnetic layer to determine the resistivity and anisotropic magnetoresistance coefficient amr of the magnetic layer when there is no magnetic field; calculating the magnetic field resistivity ρ of the magnetic layer when it is in the magnetic field according to the relationship (1.3) mr磁 The maximum and minimum values ​​of ρ mr磁 =ρ mr *(1-amr*sin2θ)(1.3),

[0014] Among them, θ represents the angle between the magnetization direction and the current direction; according to the relationship Calculate the resistance R of the magnetic layer when it is in a magnetic field mr磁 The maximum and minimum values ​​of the resistance R when the magnetic layer is in the magnetic field mr磁 The maximum and minimum values ​​of the total resistance value R of the magnetoresistive element are calculated tot_max and the minimum value of the total resistance of the magnetoresistive element R tot_min ,in,

[0015] As an implementable method, a fixed parameter value is obtained, multiple simulation values ​​of each design parameter are selected within the preset range of each design parameter, and the resistivity at multiple temperature points within the preset temperature range is measured to calculate the resistance value R of the magnetic layer. mr , the resistance value of the protective layer R b And the contact resistance value R between the metal electrode and the protective layer ct Including: determine the material and length L of the protective layer b and width W bAs the second fixed parameter, and obtain the second fixed parameter value; determine the thickness T of the protective layer b As the second design parameter, the thickness T of the protective layer is selected within the preset thickness range. b The resistivity ρ of the protective layer resistance at multiple temperature points is measured within the preset temperature range. b According to the relationship Calculate the resistance R of the protective layer at multiple temperature points when the protective layer has multiple thickness simulation values ​​within the preset thickness range b .

[0016] As an implementable approach, the preset thickness range is 20-125 nm.

[0017] As an practicable manner, the material of the protective layer is a non-magnetic conductive material.

[0018] As an implementable method, a fixed parameter value is obtained, multiple simulation values ​​of each design parameter are selected within the preset range of each design parameter, and the resistivity at multiple temperature points within the preset temperature range is measured to calculate the resistance value R of the magnetic layer. mr , the resistance value of the protective layer R b And the contact resistance value R between the metal electrode and the protective layer ct , including: determining the materials of the metal electrode and the protective layer as a third fixed parameter and obtaining the value of the third fixed parameter; determining the contact area A as a third design parameter, selecting multiple simulation values ​​of the contact area A within a preset contact area range; measuring the resistivity ρ of the contact resistance at multiple temperature points within a preset temperature range; ct According to the relationship Calculate the contact resistance R at multiple temperature points when multiple contact area simulation values ​​are within the preset contact area range ct .

[0019] As an implementable method, determining the contact area A as the third design parameter, and selecting multiple simulation values ​​of the contact area A within the preset contact area range includes: determining the width W of the connecting through hole as the third design parameter, selecting multiple simulation values ​​of the connecting through hole width W within the preset width range, and calculating multiple simulation values ​​of the contact area A based on the multiple simulation values ​​of the connecting through hole width W.

[0020] On the other hand, an embodiment of the present application provides a magnetoresistive sensor, including four magnetoresistive elements forming a Wheatstone bridge, the magnetoresistive elements including a substrate, and a magnetic layer, a protective layer, and an insulating layer sequentially arranged on the substrate, a connecting through-hole being provided on the insulating layer, a metal electrode being provided in the connecting through-hole so that the metal electrode contacts the protective layer, and one or more structural parameters in the magnetoresistive elements are determined using the above-mentioned magnetoresistive sensor optimization method.

[0021] The beneficial effects of the embodiments of the present application include:

[0022] The optimization method of the magnetoresistive sensor provided in the present application includes: establishing a simulation model of the magnetoresistive sensor, the magnetoresistive sensor including four magnetoresistive elements forming a Wheatstone bridge, the magnetoresistive elements including a substrate, and a magnetic layer, a protective layer, and an insulating layer sequentially arranged on the substrate, a connecting through-hole being opened on the insulating layer, and a metal electrode being arranged in the connecting through-hole so that the metal electrode contacts the protective layer; obtaining fixed parameter values, selecting multiple simulation values ​​of each design parameter within a preset range of each design parameter, and measuring the resistivity at multiple temperature points within a preset temperature range, and calculating the resistance value R of the magnetic layer respectively. mr , the resistance value of the protective layer R b And the contact resistance value R between the metal electrode and the protective layer ct ; According to the sensitivity calculation formula S=f(R mr ,R b ,R ct ,) Obtain the temperature-sensitivity curve of the magnetoresistive sensor corresponding to each simulation value of each design parameter in the preset temperature range; Calculate the temperature sensitivity coefficient of the magnetoresistive sensor for multiple simulation values ​​of each design parameter according to the temperature-sensitivity curve, and calculate the change rate of the temperature sensitivity coefficient; Compare the change rate of the temperature sensitivity coefficient with the change rate threshold, and the simulation value corresponding to each design parameter when it is less than or equal to the change rate threshold is used as the optimized value of each design parameter. Among them, the resistance value R of the magnetic layer mr =(S1,D1,ρ mr ), the resistance value of the protective layer R b =(S2,D2,ρ b ), the contact resistance value R between the metal electrode and the protective layer ct =(S3,D3,ρ ct ); S1 is the first design parameter, D1 is the first fixed parameter, ρ mr is the resistivity of the magnetic layer resistor, S2 is the second design parameter, D2 is the second fixed parameter, ρ b is the resistivity of the protective layer resistor, S3 is the third design parameter, D3 is the third fixed parameter, ρ ct is the contact resistivity; the temperature sensitivity coefficient is obtained by simulating the temperature-sensitivity curves of various design parameters at multiple simulation values, and the simulation value corresponding to each design parameter when the change rate of the temperature sensitivity coefficient is less than or equal to the change rate threshold is used as the optimized value, which can reduce the nonlinearity of temperature sensitivity and facilitate the setting of the back-end compensation circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0024] FIG1 is a flow chart of a method for optimizing a magnetoresistive sensor according to an embodiment of the present application;

[0025] FIG2 is a schematic diagram of a structure of a magnetoresistive element provided in an embodiment of the present application;

[0026] FIG3 is a second structural schematic diagram of a magnetoresistive element provided in an embodiment of the present application;

[0027] FIG4 is a schematic structural diagram of a magnetoresistive sensor provided in an embodiment of the present application;

[0028] FIG5 is a schematic diagram of the resistance equivalent of a magnetoresistive element provided in an embodiment of the present application;

[0029] Figure 6 shows the temperature-sensitivity curves of the magnetoresistive sensor for different protective layer thicknesses;

[0030] Figure 7 shows the change rate of the temperature sensitivity coefficient of the magnetoresistive sensor when the thickness of the protective layer is different;

[0031] FIG8 shows the temperature-sensitivity curve of the magnetoresistive sensor for different connection through-hole widths;

[0032] Figure 9 shows the change rate of the temperature sensitivity coefficient of the magnetoresistive sensor when the width of the connecting through hole is different;

[0033] FIG10 is a temperature-sensitivity curve of a magnetoresistive sensor of a comparative example;

[0034] FIG. 11 is a curve showing the change of the temperature sensitivity coefficient of the magnetoresistive sensor of the comparative example with temperature.

[0035] Icons: 10 - magnetoresistive element; 11 - substrate; 12 - magnetic layer; 13 - protective layer; 14 - insulating layer; 15 - metal electrode. DETAILED DESCRIPTION

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0038] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0039] In the description of this application, it should be noted that the terms "center," "vertical," "horizontal," "inner," and "outer" and the like indicate positions or location relationships based on the positions or location relationships shown in the accompanying drawings, or the positions or location relationships in which the product of this application is typically placed when in use. These terms are intended solely to facilitate the description of this application and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third," etc., are used solely to differentiate descriptions and should not be construed as indicating or implying relative importance.

[0040] Furthermore, terms such as "horizontal" and "vertical" do not necessarily mean that a component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0041] It should also be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0042] Magnetoresistive sensors primarily operate by utilizing the magnetoresistance effect of their magnetoresistive elements. This effect refers to the significant change in the material's resistance when a magnetic field is applied to a metal or semiconductor material carrying an electric current. However, the resistance of a magnetoresistive element also varies with temperature. Magnetoresistive elements are typically composed of a variety of different materials, each with a different temperature coefficient of resistance (TCR). This causes the magnetoresistive sensor's sensitivity to vary nonlinearly with temperature, complicating the design of back-end compensation circuitry.

[0043] The present application provides a method for optimizing a magnetoresistive sensor, as shown in FIG1 , comprising:

[0044] S10: Establish a simulation model of the magnetoresistive sensor, as shown in Figures 2, 3 and 4. The magnetoresistive sensor includes four magnetoresistive elements 10, and the four magnetoresistive elements 10 form a Wheatstone bridge. Each magnetoresistive element 10 includes a substrate 11, and a magnetic layer 12, a protective layer 13 and an insulating layer 14 sequentially arranged on the substrate 11. A connecting through hole is opened on the insulating layer 14, and a metal electrode 15 is arranged in the connecting through hole to enable the metal electrode 15 to contact the protective layer 13.

[0045] S20: Resistance value R of the magnetic layer 12 mr =(S1,D1,ρ mr ), the resistance value R of the protective layer 13 b =(S2,D2,ρ b ), the contact resistance value (referred to as contact resistance value) R between the metal electrode 15 and the protective layer 13 ct =(S3,D3,ρ ct ); S1 is the first design parameter, D1 is the first fixed parameter, ρ mr is the resistivity of the magnetic layer 12 resistor, S2 is the second design parameter, D2 is the second fixed parameter, ρ b is the resistivity of the protective layer 13 resistor, S3 is the third design parameter, D3 is the third fixed parameter, ρ ct is the resistivity of the contact resistance; D1 is one or more of the material, length, width, and thickness of the magnetic layer 12, and the rest is S1; D2 is one or more of the material, length, width, and thickness of the protective layer 13, and the rest is S2; D3 is one or more of the material of the protective layer 13, the material of the metal electrode 15, and the contact area, and the rest is S3;

[0046] Obtain the fixed parameter values, select multiple simulation values ​​of each design parameter within the preset range of each design parameter, and measure the resistivity at multiple temperature points within the preset temperature range, and calculate the resistance value R of the magnetic layer 12 respectively. mr , the resistance value R of the protective layer 13 b And the contact resistance value R ct .

[0047] Those skilled in the art should know that the resistance value of the magnetic layer 12 is Among them, ρ mr is the resistivity of the magnetic layer 12, which is related to the material of the magnetic layer 12 and the temperature T, L mr is the length of the magnetic layer 12, W mr is the width of the magnetic layer 12, T mris the thickness of the magnetic layer 12. Based on this, D1 is one or more of the material, length, width, and thickness of the magnetic layer 12, and the rest is S1. That is, one or more of the material, length, width, and thickness of the magnetic layer 12 can be used as D1, and the rest can be used as S1. Alternatively, the material, length, width, and thickness of the magnetic layer 12 can all be used as D1, and S1 is not set. D1 can be determined based on empirical data, experimental data, conventional design, or current process conditions. S1 selects multiple simulation values ​​from the preset range of the first design parameter, and measures ρ at multiple temperature points within the preset temperature range. mr , and calculate the resistance value R of the magnetic layer 12 mr .

[0048] Resistance value of protective layer 13 Among them, ρ b is the resistivity of the protective layer 13, which is related to the material of the protective layer 13 and the temperature T, L b is the length of the protective layer 13, W b is the width of the protective layer 13, T b is the thickness of the protective layer 13. D2 is one or more of the material, length, width and thickness of the protective layer 13, and the rest is S2. That is, one or more of the material, length, width and thickness of the protective layer 13 can be used as D2, and the rest one or more can be used as S2. Alternatively, the material, length, width and thickness of the protective layer 13 can all be used as D2, and S2 is not set. D2 can be determined based on empirical data, experimental data, conventional design or current process conditions, and S2 selects multiple simulation values ​​from the preset range of the second design parameter, and measures ρ at multiple temperature points within the preset temperature range. b , and calculate the resistance value R of the protective layer 13 b .

[0049] Contact resistance where ρ ctis the contact resistivity, which is related to the materials of the protective layer 13 and the metal electrode 15 in contact with each other and the temperature T, and A is the contact surface area. D3 is one or more of the material of the protective layer 13, the material of the metal electrode 15, and the contact area between the protective layer 13 and the metal electrode 15, and the rest are S3. That is, the material of the protective layer 13, the material of the metal electrode 15, and the contact area between the protective layer 13 and the metal electrode 15 can be used as D3, and the rest one or more can be used as S3. Alternatively, the material of the protective layer 13, the material of the metal electrode 15, and the contact area between the protective layer 13 and the metal electrode 15 can all be used as D3, and S3 is not set. D3 can determine the relevant value based on empirical data, experimental data, conventional design or current process conditions, and S3 selects multiple simulation values ​​from the preset range of the third design parameter, and measures ρ at multiple temperature points within the preset temperature range. ct , and calculate the contact resistance value R ct .

[0050] Measure ρ at multiple temperature points within a preset temperature range mr , ρ b and ρ ct , which can be measured by the four-probe method.

[0051] S30: According to the sensitivity calculation formula S=f(R mr ,R b ,R ct ,) obtain multiple temperature-sensitivity curves of the magnetoresistive sensor in the preset temperature range.

[0052] Based on the resistance value R of the magnetic layer 12 mr , the resistance value R of the protective layer 13 b And the contact resistance value R ct The sensitivity of multiple temperature points is calculated within the corresponding temperature preset range, and a temperature sensitivity curve is formed. Specifically, a first fixed parameter D1 is obtained; a finite number of simulation values ​​are selected for the first design parameter S1 within the first preset parameter preset range; the resistivity ρ of the resistance of the magnetic layer 12 is mr It is related to the temperature T, so the resistivity ρ of the magnetic layer 12 resistance at multiple temperature points needs to be measured within the temperature preset range. mr Thus, for the same simulation value of the first design parameter S1, the resistance value R of the magnetic layer 12 obtained at different temperature points in the temperature preset range is mr Because the first design parameter S1 has multiple simulation values, therefore, for the same temperature point the resistivity of the magnetic layer 12 resistance ρ mr , based on the simulation values ​​of different first design parameters S1, the resistance value R of the magnetic layer 12 is obtained. mrSimilarly, for the simulation value of the same second design parameter S2, the resistance value R of the protective layer 13 obtained at different temperature points in the temperature preset range is b Different, for the same temperature point the resistivity ρ of the protective layer 13 resistance b Based on the simulation values ​​of different second design parameters S2, the resistance value R of the protective layer 13 is obtained. b Also different; and, for the simulation value of the same third design parameter S3, the contact resistance value R obtained at different temperature points in the temperature preset range ct Different, the resistivity ρ of the contact resistance at the same temperature point ct , based on the simulation values ​​of different third design parameters S3, the resistance value of the contact resistance R ct That is, after selecting a simulation value for each design parameter, the sensitivity obtained at different temperature points in the preset temperature range is different, that is, a temperature-sensitivity curve can be obtained. Moreover, after simulating a finite number of simulation values ​​of multiple design parameters, multiple temperature-sensitivity curves can be obtained.

[0053] Among them, the first design parameter, the second design parameter and the third design parameter are used as design parameters, and a finite number of simulation value combinations of one or more design parameters can be simulated at the same time; or multiple simulation values ​​of one design parameter can be simulated to obtain the optimized value first, and then multiple simulation values ​​of the second design parameter can be simulated based on the optimized value of the first design parameter, and so on, to complete the acquisition of the optimized values ​​of all design parameters. Among them, when simulating multiple simulation values ​​of the first design parameter, the values ​​of the remaining design parameters can be preset according to empirical values.

[0054] It is understandable that obtaining multiple temperature-sensitivity curves does not require actually drawing the curves. It is sufficient to obtain multiple sets of temperature-sensitivity data to facilitate the subsequent calculation of the temperature sensitivity coefficient.

[0055] S40: Calculating temperature sensitivity coefficients of the magnetoresistive sensor for multiple simulation values ​​of the design parameters according to the temperature-sensitivity curve, and calculating the rate of change of the temperature sensitivity coefficient.

[0056] S50: Compare the change rate of the temperature sensitivity coefficient with the change rate threshold, and use the simulation value corresponding to each design parameter when the value is less than or equal to the change rate threshold as the optimized value of the design parameter.

[0057] When the rate of change of the temperature sensitivity coefficient is less than or equal to the rate of change threshold, the temperature sensitivity change rate of the magnetoresistive sensor meets the requirements, so that the temperature sensitivity coefficient does not change much with temperature, thereby reducing the nonlinearity of the temperature sensitivity curve and facilitating the setting of the back-end compensation circuit.

[0058] For example, the simulation values ​​of each design parameter corresponding to the minimum rate of change of the temperature sensitivity coefficient can be selected as the optimization result. Because when the rate of change of the temperature sensitivity coefficient is the smallest, that is, when the temperature sensitivity coefficient does not change much, it means that the sensitivity changes linearly or basically linearly with temperature. Then the simulation value of the design parameter corresponding to the minimum rate of change of the temperature sensitivity coefficient is the optimized value, which is used as the optimized value of the design parameter.

[0059] The embodiment of the present application simulates the temperature-sensitivity curve of each design parameter at multiple simulation values, calculates the temperature sensitivity coefficient based on the temperature-sensitivity curve, and selects the simulation value corresponding to the design parameter when the change rate of the temperature sensitivity coefficient is less than or equal to the change rate threshold as the optimized value, which can reduce the nonlinearity of the temperature sensitivity curve and facilitate the setting of the back-end compensation circuit.

[0060] The magnetoresistive element 10 in the embodiment of the present application is an anisotropic magnetoresistive element.

[0061] For example, the substrate 11 may be a thermally oxidized silicon wafer.

[0062] There is no limitation on the specific material of the magnetic layer 12, as long as it has good anisotropic magnetoresistance characteristics, that is, has a high anisotropic magnetoresistance rate. For example, it can be a nickel-iron alloy, specifically, Ni 81 Fe 19 When the magnetic layer 12 is made of nickel-iron alloy, in order to make the magnetic layer 12 have good anisotropic magnetoresistance characteristics, the thickness of the magnetic layer 12 is 15 nm-30 nm.

[0063] The specific material of the protective layer 13 is not limited in the embodiment of the present application, as long as it can play a protective role and does not affect the normal operation of the magnetic layer 12. In one feasible method of the embodiment of the present application, the material of the protective layer 13 is a non-magnetic conductive material. The protective layer 13 is provided on the magnetic layer 12. As a protective layer 13 of the magnetic layer 12, it should be a non-magnetic material to avoid interfering with the magnetism of the magnetic layer 12; secondly, the material of the protective layer 13 cannot react with the magnetic layer 12, causing the material of the magnetic layer 12 to change; in addition, in order to achieve electrical connection with the outside world, the protective layer 13 should be a conductive material. Therefore, the protective layer 13 should be a non-magnetic conductive material that does not chemically react with the magnetic layer 12. At the same time, in order to ensure the magnetic sensitivity of the magnetic layer 12, the resistivity of the protective layer 13 should be relatively higher than that of the magnetic layer 12 to prevent the sensitivity of the magnetic layer 12 from being reduced due to shunting of the protective layer 13. It can be a conductive material such as TaN or TiN. Of course, those skilled in the art can also make other selections for the material of the protective layer 13 based on the above situation.

[0064] The specific material of the insulating layer 14 is not limited in the present embodiment, as long as it can provide insulation and does not affect the normal operation of the magnetic layer 12. In one possible implementation of the present embodiment, the insulating layer 14 is made of SiO2 or Si3N4.

[0065] The insulating layer 14 can be wet-etched or dry-etched to penetrate the insulating layer 14 to the upper surface of the protective layer 13 to form a connecting through hole. The connecting through hole is usually arranged in a parallelogram shape, and the acute angle formed between two adjacent sides of the parallelogram is set to be between 35° and 55°, and can be 45° for example.

[0066] Metal electrodes 15 are made of a material with good electrical conductivity, such as copper or aluminum. Metal electrodes 15 provide electrical connections between magnetoresistive elements 10 and between magnetoresistive elements 10 and peripheral circuits. Metal electrodes 15 contact protective layer 13 through connecting vias, creating contact resistance.

[0067] Please refer to Figure 2 again. The substrate 11, the magnetic layer 12, the protective layer 13 and the insulating layer 14 are all the same in length and width. Therefore, when the length dimension value of one of the substrate 11, the magnetic layer 12, the protective layer 13 and the insulating layer 14 is determined, the length dimension values ​​of the other ones of the substrate 11, the magnetic layer 12, the protective layer 13 and the insulating layer 14 are determined accordingly. Similarly, when the width dimension value of one of the substrate 11, the magnetic layer 12, the protective layer 13 and the insulating layer 14 is determined, the width dimension values ​​of the other ones of the substrate 11, the magnetic layer 12, the protective layer 13 and the insulating layer 14 are determined accordingly.

[0068] In one possible implementation of the present application, a fixed parameter value is obtained, multiple simulation values ​​of each design parameter are selected within the preset range of each design parameter, and the resistivity at multiple temperature points within the preset temperature range is measured to calculate the resistance value R of the magnetic layer 12. mr , the resistance value R of the protective layer 13 b and the contact resistance value R between the metal electrode 15 and the protective layer 13 ct include:

[0069] S21: Determine the material and length L of the protective layer 13 b and width W b as a second fixed parameter, and obtaining a second fixed parameter value;

[0070] S22: Determine the thickness T of the protective layer 13 b As the second design parameter, the thickness T of the protective layer 13 is selected within the preset thickness range. b Multiple simulation values ​​of ;

[0071] S23: Measuring the resistivity ρ of the protective layer 13 at multiple temperature points within a preset temperature range b ;

[0072] S24: According to the relationship Calculate the protective layer resistance R at multiple temperature points when the protective layer 13 has multiple thickness simulation values ​​within the preset thickness range. b .

[0073] In order to ensure that the protective layer 13 can play a protective role and does not affect the normal operation of the magnetic layer 12 , the thickness of the protective layer 13 is 20 nm-125 nm, that is, the preset thickness range is 20 nm-125 nm.

[0074] In one possible implementation of the present application, a fixed parameter value is obtained, multiple simulation values ​​of each design parameter are selected within the preset range of each design parameter, and the resistivity at multiple temperature points within the preset temperature range is measured to calculate the resistance value R of the magnetic layer 12. mr , the resistance value R of the protective layer 13 b and the contact resistance value R between the metal electrode 15 and the protective layer 13 ct include:

[0075] S21′: determining the materials of the metal electrode 15 and the protective layer 13 as a third fixed parameter, and obtaining a value of the third fixed parameter;

[0076] S22′: determining the contact area A as a third design parameter, and selecting multiple simulation values ​​of the contact area A within a preset contact area range;

[0077] S23': Measure the resistivity ρ of the contact resistance at multiple temperature points within the preset temperature range ct ;

[0078] S24': According to the relation Calculate the contact resistance R at multiple temperature points when multiple contact area simulation values ​​are within the preset contact area range ct .

[0079] As shown in FIG3 , the contact area A is adjusted by adjusting the size of the connecting through hole. The contact area A = the height of the connecting through hole (i.e., the height of the parallelogram) × the width W of the connecting through hole. The height of the connecting through hole is substantially equal to the width of the insulating layer 14. Therefore, the contact area A is adjusted by adjusting the width W of the connecting through hole. That is, the contact area A is determined as the third design parameter, and multiple simulation values ​​of the contact area A are selected within the preset contact area range, including:

[0080] The width W of the connecting through hole is determined as a third design parameter, multiple simulation values ​​of the connecting through hole width W are selected within a preset width range, and multiple simulation values ​​of the contact area A are calculated based on the multiple simulation values ​​of the connecting through hole width W.

[0081] The preset width interval of the width W of the connecting through hole is set based on the acute angle formed between two adjacent sides of the parallelogram, and the width and length of the insulating layer 14 .

[0082] In one possible implementation of the present invention, according to the sensitivity calculation formula S=f(R mr ,R b ,R ct ,) Obtaining the temperature-sensitivity curve of the magnetoresistive sensor corresponding to each simulation value of each design parameter in the temperature preset range, including:

[0083] S31: Calculate the sensitivity of the magnetoresistive sensor at each simulation value according to the relationship (1.1).

[0084] Where S is the sensitivity of the magnetoresistive sensor, V out is the maximum differential signal output of the magnetoresistive sensor under the saturation magnetic field Hs and unit power supply voltage; H S is the saturation magnetic field; R tot is the total resistance of the magnetoresistive element 10, R tot_max is the maximum value of the total resistance of the magnetoresistive element 10, R tot_min is the minimum value of the total resistance of the magnetoresistive element 10.

[0085] S32: forming a plurality of temperature-sensitivity curves according to the calculated sensitivities corresponding to a plurality of temperature points within the preset temperature range.

[0086] The magnetoresistive sensor includes four magnetoresistive elements 10, which form a Wheatstone bridge. As shown in FIG4 , the maximum differential signal output of the Wheatstone bridge structure under a saturation magnetic field Hs and a unit power supply voltage is V out , can be configured to represent the size of the external magnetic field. The sensitivity of the magnetoresistive sensor is S, which is the value of the maximum differential output signal under the unit magnetic field size. R tot is the total resistance value of the magnetoresistive element 10. For anisotropic magnetoresistive element 10, which is a multilayer film structure, the current conduction direction is parallel to the plane of the multilayer film structure. The resistance equivalent diagram of the magnetoresistive element 10 is shown in FIG5 . Therefore, the total resistance value of the magnetoresistive element 10 is

[0087] In one achievable manner of the embodiment of the present application, the temperature sensitivity coefficients of the magnetoresistive sensor for multiple simulation values ​​of each design parameter are calculated based on the temperature-sensitivity curve, and the rate of change of the temperature sensitivity coefficient is calculated, including:

[0088] S41: Calculate the temperature sensitivity coefficient of the magnetoresistive sensor for each simulation value of each design parameter according to the relationship (1.2).

[0089] Where TCS is the temperature sensitivity coefficient of the magnetoresistive sensor, is the sensitivity of the magnetoresistive sensor at temperature T1, is the sensitivity of the magnetoresistive sensor at the reference temperature T0.

[0090] It is understandable that both T0 and T1 belong to the preset temperature range. In practical applications, the reference temperature T0 can be the commonly used ambient temperature of the magnetoresistive sensor. Those skilled in the art can set it according to the ambient temperature of the magnetoresistive sensor. For example, it can be set to 20°C.

[0091] S42: Calculate the change rate of the temperature sensitivity coefficient under each simulation value of each design parameter.

[0092] Specifically, the maximum and minimum values ​​of the temperature sensitivity coefficient can be selected, and the rate of change between the maximum and minimum values ​​of the temperature sensitivity coefficient can be calculated based on the maximum and minimum values ​​of the temperature sensitivity coefficient, that is, the maximum rate of change of the temperature sensitivity coefficient. When the maximum rate of change of the temperature sensitivity coefficient is the smallest, the temperature sensitivity curve of the magnetoresistive sensor optimized in the embodiment of the present application can be made as linear as possible.

[0093] In one possible implementation of the embodiment of the present application, the sensitivity of the magnetoresistive sensor at each simulation value is calculated according to the relationship (1.1), including:

[0094] S311: Determine the material of the magnetic layer 12 to determine the resistivity and anisotropic magnetoresistance coefficient amr of the magnetic layer 12 when there is no magnetic field;

[0095] S312: Calculate the magnetic field resistivity ρ of the magnetic layer 12 when it is in the magnetic field according to the relationship (1.3) mr磁 The maximum and minimum values ​​of ρ mr磁 =ρ mr *(1-amr*sin2θ) (1.3),

[0096] Where θ represents the angle between the magnetization direction and the current direction;

[0097] S313: According to the relationship Calculate the resistance value R of the magnetic layer 12 when it is in a magnetic fieldmr磁 The maximum and minimum values ​​of ;

[0098] S314: Based on the resistance value R of the magnetic layer 12 when it is in the magnetic field mr磁 The maximum value R of the total resistance value of the magnetoresistive element 10 is calculated from the maximum value and minimum value tot_max and the minimum value R of the total resistance value of the magnetoresistive element 10 tot_min ,

[0099] The minimum value R of the total resistance value of the magnetoresistive element 10 tot_min and the maximum value R of the total resistance value of the magnetoresistive element 10 tot_max According to the resistance value R of the magnetic layer 12 when it is in a magnetic field mr磁 The maximum resistance value and the minimum resistance value are determined by the maximum resistance value and the minimum resistance value of the magnetic layer 12 in the magnetic field. Further, when the resistivity of the magnetic layer 12 is the largest, the resistance value R mr磁 The maximum resistance value of the magnetic layer 12 is the minimum when the resistivity of the magnetic layer 12 is in the magnetic field, which corresponds to the resistance value R when the magnetic layer 12 is in the magnetic field. mr磁 In addition, when the magnetic layer 12 is made of Ni 81 Fe 19 When the anisotropic magnetoresistance coefficient amr is about 3%, it can be obtained by measuring with the four-probe method.

[0100] The present application also discloses a magnetoresistive sensor comprising four magnetoresistive elements 10 forming a Wheatstone bridge. The magnetoresistive elements 10 include a substrate 11, and a magnetic layer 12, a protective layer 13, and an insulating layer 14 sequentially disposed on the substrate 11. The insulating layer 14 includes a connecting through-hole, and a metal electrode 15 is disposed within the connecting through-hole to allow contact between the metal electrode 15 and the protective layer 13. One or more structural parameters of the magnetoresistive elements 10 are determined using the aforementioned magnetoresistive sensor optimization method. Because one or more structural parameters of the magnetoresistive elements 10 are determined using the aforementioned magnetoresistive optimization method, the sensitivity of the magnetoresistive sensor provided in the present application embodiment varies as linearly as possible with temperature, facilitating the configuration of a back-end compensation circuit.

[0101] Example 1

[0102] The magnetic layer 12 of the magnetoresistive sensor is made of nickel-iron alloy, with a length of 120 μm, a width of 5 μm, and a thickness of 20 nm. The protective layer 13 is made of TaN, with a length of 120 μm and a width of 5 μm. The metal electrode 15 is made of aluminum, and the width of the connecting through-hole is 4 μm. The preset temperature range is -40°C to 150°C, and the resistivity is measured at multiple temperature points within the preset temperature range. The temperature-sensitivity relationship of the magnetic sensor was simulated by selecting protective layers 13 of different thicknesses. Specifically, the thicknesses of the protective layers 13 selected were 20 nm, 40 nm, 60 nm, and 80 nm, respectively. The simulation results are shown in FIG6 , which shows the temperature-sensitivity curves of the magnetoresistive sensor for various simulated thickness values. Then, the change rate of the temperature sensitivity coefficient within the preset temperature range (-40°C to 150°C) for different thicknesses is calculated, as shown in Figure 7. As can be seen from Figure 7, the simulation results show that as the thickness of the protective layer 13 changes from 20nm to 80nm, the maximum TCS change rate can be reduced from 176% to 4%, and 80nm can be used as the optimized value of the thickness of the protective layer 13.

[0103] Example 2

[0104] The material of the magnetic layer 12 of the magnetoresistive sensor is nickel-iron alloy, the length of the magnetic layer 12 is 120 μm, the width of the magnetic layer 12 is 5 μm, and the thickness of the magnetic layer 12 is 20 nm. The material of the protective layer 13 is TaN, the length of the protective layer 13 is 120 μm, the width of the protective layer 13 is 5 μm, and the thickness of the protective layer is 80 nm. The material of the metal electrode 15 is aluminum. The temperature preset range is -40°C to 150°C, and the resistivity at multiple temperature points within the preset temperature range is measured. The temperature-sensitivity relationship of the magnetic sensor is simulated by selecting different widths of the connecting through-holes. Specifically, the widths of the connecting through-holes are selected as 2μm, 3μm, 4μm, 5μm, and 6μm, respectively. The simulation results are shown in FIG8 . The temperature-sensitivity curves of the magnetoresistive sensor are obtained for multiple widths of the connecting through-holes, and then the rate of change of the temperature sensitivity coefficient within the preset temperature range (-40°C to 150°C) for different widths is calculated, as shown in FIG9 . As can be seen from FIG9 , the simulation results show that as the width of the connecting through-hole changes from 2μm to 6μm, the maximum rate of change of TCS can be reduced to 2.4%, and 5μm can be used as the optimized value of the width of the connecting through-hole.

[0105] Comparative Example

[0106] In order to further demonstrate the beneficial effects of the magnetoresistive sensor provided by the embodiment of the present application, the present application provides a magnetoresistive sensor in the related art as a comparative example, wherein the material of the magnetic layer 12 is nickel-iron alloy, the length of the magnetic layer 12 is 120 μm, the width of the magnetic layer 12 is 5 μm, and the thickness of the magnetic layer 12 is 30 nm. The material of the protective layer 13 is TaN, the length of the protective layer 13 is 120 μm, the width of the protective layer 13 is 5 μm, and the thickness of the protective layer 13 is 40 nm. The material of the metal electrode 15 is aluminum, the width of the connecting through hole is 4 μm, and the preset temperature range is -40°C to 150°C. FIG. 10 FIG10 and FIG11 are respectively the temperature-sensitivity curve and the temperature-temperature sensitivity coefficient curve of the comparative example. As can be seen from FIG10, in the lower temperature range (-40℃~60℃), the sensitivity of the magnetoresistive sensor gradually increases, and in the higher temperature range (60℃~150℃), the sensitivity of the magnetoresistive sensor gradually decreases. Taking 20℃ as the reference temperature, the temperature sensitivity coefficient of the sensor gradually changes from greater than zero to less than zero in the entire operating environment temperature. When the sensitivity of the magnetoresistive sensor needs to be compensated, compensation needs to be performed separately for different temperature ranges, thereby greatly increasing the complexity of the compensation circuit design. The magnetoresistive sensor provided in the embodiment of the present application simulates the design parameters and selects the optimized values, so that the sensitivity of the magnetoresistive sensor of the embodiment of the present application is almost linear with the temperature, thereby reducing the complexity of the back-end compensation circuit design.

[0107] The above description is merely an optional embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included within the scope of protection of the present application. Industrial Applicability

[0108] The above scheme is adopted to establish a simulation model of a magnetoresistive sensor. The magnetoresistive sensor includes four magnetoresistive elements constituting a Wheatstone bridge. The magnetoresistive element includes a substrate, and a magnetic layer, a protective layer, and an insulating layer sequentially arranged on the substrate. A connecting through-hole is opened on the insulating layer. A metal electrode is arranged in the connecting through-hole so that the metal electrode contacts the protective layer. A fixed parameter value is obtained, and multiple simulation values ​​of each design parameter are selected within a preset range of each design parameter. The resistivity at multiple temperature points is measured within a preset temperature range, and the resistance value R of the magnetic layer is calculated respectively. mr , the resistance value of the protective layer R b And the contact resistance value R between the metal electrode and the protective layer ct According to the sensitivity calculation formula S=f(R mr ,R b ,R ct,) Obtain the temperature-sensitivity curve of the magnetoresistive sensor corresponding to each simulation value of each design parameter in the preset temperature range, calculate the temperature sensitivity coefficient of the magnetoresistive sensor for multiple simulation values ​​of each design parameter according to the temperature-sensitivity curve, and calculate the rate of change of the temperature sensitivity coefficient, compare the rate of change of the temperature sensitivity coefficient with the rate of change threshold, and use the simulation value corresponding to each design parameter when it is less than or equal to the rate of change threshold as the optimized value of each design parameter. By simulating the temperature-sensitivity curve of each design parameter at multiple simulation values, the temperature sensitivity coefficient is obtained, and the simulation value corresponding to each design parameter when the rate of change of the temperature sensitivity coefficient is less than or equal to the rate of change threshold is used as the optimized value, which can reduce the nonlinearity of temperature sensitivity and facilitate the setting of the back-end compensation circuit.

Claims

1. A method for optimizing a magnetoresistive sensor, characterized in that: include: A simulation model of a magnetoresistive sensor is established, wherein the magnetoresistive sensor includes four magnetoresistive elements constituting a Wheatstone bridge, wherein the magnetoresistive element includes a substrate, and a magnetic layer, a protective layer, and an insulating layer sequentially arranged on the substrate, wherein a connecting through hole is opened on the insulating layer, and a metal electrode is arranged in the connecting through hole so that the metal electrode contacts the protective layer; Obtain fixed parameter values, select multiple simulation values ​​of each design parameter within each preset range of the design parameters, and measure the resistivity at multiple temperature points within the preset temperature range to calculate the resistance value R of the magnetic layer. mr , the resistance value R of the protective layer b and the contact resistance value R between the metal electrode and the protective layer ct , wherein the resistance value of the magnetic layer R mr =(S1,D1,ρ mr ), the resistance value of the protective layer R b =(S2,D2,ρ b ), the contact resistance value R between the metal electrode and the protective layer ct =(S3,D3,ρ ct ); S1 is the first design parameter, D1 is the first fixed parameter, ρ mr is the resistivity of the magnetic layer, S2 is the second design parameter, D2 is the second fixed parameter, ρ b is the resistivity of the protective layer, S3 is the third design parameter, D3 is the third fixed parameter, ρ ct is the contact resistivity; D1 is one or more of the material, length, width and thickness of the magnetic layer, and the rest is S1; D2 is one or more of the material, length, width and thickness of the protective layer, and the rest is S2; D3 is one or more of the material of the protective layer, the material of the metal electrode, and the contact area, and the rest is S3; According to the sensitivity calculation formula S = f(R mr ,R b ,R ct ,) obtaining a temperature-sensitivity curve of the magnetoresistive sensor corresponding to each simulation value of each of the design parameters in a preset temperature range; According to the temperature-sensitivity curve, respectively calculate the temperature sensitivity coefficient of the magnetoresistive sensor of the plurality of simulation values ​​of each of the design parameters, and calculate the change rate of the temperature sensitivity coefficient; The change rate of the temperature sensitivity coefficient is compared with a change rate threshold, and the simulation value corresponding to each of the design parameters when it is less than or equal to the change rate threshold is used as the optimized value of the design parameter.

2. The optimization method of the magnetoresistive sensor according to claim 1, characterized in that: The calculation formula according to the sensitivity S = f (R mr ,R b ,R ct ,) obtaining the temperature-sensitivity curve of the magnetoresistive sensor corresponding to each simulation value of each design parameter in the preset temperature range, including: According to the relationship (1.1), the sensitivity of the magnetoresistive sensor at each simulation value is calculated. Where S is the sensitivity of the magnetoresistive sensor, V out is the maximum differential signal output of the magnetoresistive sensor under the saturation magnetic field Hs and unit power supply voltage; H S is the saturation magnetic field; R tot is the total resistance of the magnetoresistive element, R tot_max is the maximum value of the total resistance of the magnetoresistive element, R tpt_min is the minimum value of the total resistance of the magnetoresistive element; A plurality of temperature-sensitivity curves are formed according to the calculated sensitivities corresponding to a plurality of temperature points within the preset temperature range.

3. The method for optimizing a magnetoresistive sensor according to claim 1 or 2, characterized in that: The step of calculating the temperature sensitivity coefficient of the magnetoresistive sensor for each of the plurality of simulation values ​​of the design parameters according to the temperature-sensitivity curve, and calculating the rate of change of the temperature sensitivity coefficient comprises: The temperature sensitivity coefficient of the magnetoresistive sensor for each simulation value of each design parameter is calculated according to the relation (1.2), Where TCS is the temperature sensitivity coefficient of the magnetoresistive sensor, is the sensitivity of the magnetoresistive sensor at temperature T1, is the sensitivity of the magnetoresistive sensor at the reference temperature T0; The change rate of the temperature sensitivity coefficient at each simulation value of each of the design parameters is calculated.

4. The optimization method of the magnetoresistive sensor according to claim 2, characterized in that: The calculation of the sensitivity of the magnetoresistive sensor at each simulation value according to the relation (1.1) includes: Determining the material of the magnetic layer to determine the resistivity and anisotropic magnetoresistance coefficient amr of the magnetic layer when there is no magnetic field; According to the relationship (1.3), the magnetic field resistivity ρ when the magnetic layer is in the magnetic field is calculated mr磁 The maximum and minimum values ​​of r mr磁 =ρ mr *(1-amr*sin2θ) (1.3) Among them, θ represents the angle between the magnetization direction and the current direction; According to the relation Calculate the resistance value R of the magnetic layer when it is in a magnetic field mr磁 The maximum and minimum values ​​of According to the resistance value R of the magnetic layer when it is in the magnetic field mr磁 The maximum and minimum values ​​are used to calculate the maximum value of the total resistance value R of the magnetoresistive element. tot_max and the minimum value of the total resistance of the magnetoresistive element R tot_min ,in, 5. The method for optimizing a magnetoresistive sensor according to any one of claims 1 to 4, characterized in that: The fixed parameter value is obtained, multiple simulation values ​​of each design parameter are selected within the preset range of each design parameter, and the resistivity at multiple temperature points is measured within the preset temperature range to calculate the resistance value R of the magnetic layer. mr , the resistance value of the protective layer R b and the contact resistance value R between the metal electrode and the protective layer ct ,include: Determine the material and length L of the protective layer b and width W b as a second fixed parameter, and obtaining a second fixed parameter value; Determine the thickness T of the protective layer b is the second design parameter, and the thickness T of the protective layer is selected within the preset thickness range. b Multiple simulation values ​​of ; The resistivity ρ of the protective layer resistance is measured at multiple temperature points within a preset temperature range. b ; According to the relation Calculate the resistance R of the protective layer at multiple temperature points when the protective layer has multiple thickness simulation values ​​within a preset thickness range b .

6. The method for optimizing a magnetoresistive sensor according to claim 5, characterized in that: The preset thickness range is 20-125 nm.

7. The method for optimizing a magnetoresistive sensor according to claim 5 or 6, characterized in that: The material of the protection layer is a non-magnetic conductive material.

8. The method for optimizing a magnetoresistive sensor according to any one of claims 1 to 7, characterized in that: The fixed parameter value is obtained, multiple simulation values ​​of each design parameter are selected within the preset range of each design parameter, and the resistivity at multiple temperature points is measured within the preset temperature range to calculate the resistance value R of the magnetic layer. mr , the resistance value of the protective layer R b and the contact resistance value R between the metal electrode and the protective layer ct ,include: Determining the materials of the metal electrode and the protective layer as a third fixed parameter, and obtaining a value of the third fixed parameter; Determine the contact area A as the third design parameter, and select multiple simulation values ​​of the contact area A within a preset contact area range; Measure the resistivity ρ of the contact resistance at multiple temperature points within the preset temperature range cy ; According to the relation Calculate the contact resistance R at multiple temperature points when multiple contact area simulation values ​​are within the preset contact area range ct .

9. The method for optimizing a magnetoresistive sensor according to claim 8, characterized in that: The step of determining the contact area A as the third design parameter and selecting multiple simulation values ​​of the contact area A within a preset contact area interval includes: The width W of the connecting through hole is determined as a third design parameter, multiple simulation values ​​of the connecting through hole width W are selected within a preset width range, and multiple simulation values ​​of the contact areas A are calculated based on the multiple simulation values ​​of the connecting through hole width W.

10. The method for optimizing a magnetoresistive sensor according to claim 3, characterized in that: The calculating the change rate of the temperature sensitivity coefficient under each simulation value of each design parameter includes: Determine the maximum and minimum values ​​of the temperature sensitivity coefficients under each simulation value of each of the design parameters; The rate of change between the maximum value and the minimum value of the temperature sensitivity coefficient is calculated.

11. The method for optimizing a magnetoresistive sensor according to any one of claims 1 to 10, characterized in that: The comparing the rate of change of the temperature sensitivity coefficient with a rate of change threshold, and taking the simulation value corresponding to each of the design parameters when the value is less than or equal to the rate of change threshold as the optimized value of the design parameter, includes: The simulation value corresponding to the design parameter when the minimum value of the rate of change of the temperature sensitivity coefficient is determined is used as the optimized value of the design parameter.

12. The magnetoresistive sensor according to any one of claims 1 to 11, characterized in that: The thickness of the magnetic layer is 15nm-30nm.

13. The method for optimizing a magnetoresistive sensor according to any one of claims 1 to 12, characterized in that: The resistivity of the protection layer is higher than that of the magnetic layer.

14. The magnetoresistive sensor according to any one of claims 1 to 13, characterized in that: The magnetoresistive element is an anisotropic magnetoresistive element.

15. A magnetoresistive sensor, characterized in that: The invention comprises four magnetoresistive elements constituting a Wheatstone bridge, wherein the magnetoresistive elements comprise a substrate, and a magnetic layer, a protective layer and an insulating layer sequentially arranged on the substrate, wherein the insulating layer is provided with a connecting through hole, and a metal electrode is arranged in the connecting through hole so that the metal electrode contacts the protective layer, and one or more structural parameters in the magnetoresistive element are determined by the optimization method of the magnetoresistive sensor according to any one of claims 1 to 14.

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