Magnetoresistive sensor, method for producing a magnetoresistive sensor and magnetoresistive device
By inserting a light metal material or its oxide into the magnetoresistive sensor as a linear enhancement layer, the problem of low linearity and sensitivity caused by large hysteresis is solved, and higher linearity and sensitivity are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG HIKSTOR TECHOGY CO LTD
- Filing Date
- 2024-11-29
- Publication Date
- 2026-05-29
AI Technical Summary
Existing magnetoresistive sensors suffer from large hysteresis, leading to problems with low linearity and sensitivity.
A light metal material or its oxide is inserted into the magnetoresistive sensor as a linear reinforcement layer, located between the first electrode and the free layer, with its thickness controlled between 0.1 nm and 0.3 nm, to improve the interface quality.
This reduces hysteresis and improves the linearity and sensitivity of the magnetoresistive sensor.
Smart Images
Figure CN122121533A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of magnetoresistive sensors, and more specifically, to a magnetoresistive sensor, a method for fabricating a magnetoresistive sensor, and a magnetoresistive device. Background Technology
[0002] Magnetic tunnel junctions (MTJs) based on the CoFeB-MgO structure exhibit a huge tunnel magnetoresistance (TMR) effect. Due to their potential for high sensitivity, low power consumption, and micron-sized components, they are key devices for various magnetic sensing spintronics applications.
[0003] Tunneling magnetoresistive (TMR) sensors are the only viable alternative to Hall sensors for detecting vertical magnetic fields, offering advantages such as low noise and small size. They must exhibit linearity (low hysteresis), requiring the sensing layer's magnetization direction to be in-plane and the fixed layer's magnetization direction to be vertically oriented, thus achieving a cross-configuration.
[0004] However, in-plane orientation of the sensing layer results in lower sensor sensitivity. The solution to this problem is to tilt the magnetization direction of the sensing layer (i.e., to be at the critical state between in-plane and out-of-plane). However, the drawback of this method is increased hysteresis, so a method to reduce hysteresis is needed. Summary of the Invention
[0005] The main objective of this application is to provide a magnetoresistive sensor, a method for fabricating a magnetoresistive sensor, and a magnetoresistive device to solve the problem that the large hysteresis of magnetoresistive sensors in the prior art leads to low linearity and sensitivity.
[0006] To achieve the above objectives, according to one aspect of this application, a magnetoresistive sensor is provided, comprising: a first electrode; a linear enhancement layer located on the surface of the first electrode, the material of the linear enhancement layer comprising a light metal and / or its oxide; and a free layer located on the surface of the linear enhancement layer away from the first electrode.
[0007] Optionally, the thickness of the linear enhancement layer does not exceed 0.3 nm.
[0008] Optionally, the magnetoresistive sensor further includes: a barrier layer located on the surface of the free layer away from the linear enhancement layer; a fixed layer located on the surface of the barrier layer away from the free layer; and a second electrode located on the surface of the fixed layer away from the barrier layer.
[0009] Optionally, the material of the linear reinforcement layer includes Mg and / or Cu.
[0010] Optionally, the first electrode is the top electrode and the second electrode is the bottom electrode.
[0011] Optionally, the first electrode is the bottom electrode and the second electrode is the top electrode.
[0012] Optionally, the thickness of the linear enhancement layer is 0.1 nm to 0.3 nm.
[0013] According to another aspect of this application, a method for fabricating any of the magnetoresistive sensors is provided, comprising: providing a first electrode; forming a linear reinforcement layer on the surface of the first electrode, the material of the linear reinforcement layer comprising a light metal and / or its oxide; and forming a free layer on the surface of the linear reinforcement layer away from the first electrode.
[0014] Optionally, the first electrode is a bottom electrode, and forming a linear reinforcement layer on the surface of the first electrode includes: forming a preliminary linear reinforcement layer on the surface of the bottom electrode; subjecting the preliminary linear reinforcement layer to an oxygen-permeable treatment to achieve oxidation; and subjecting the oxidized preliminary linear reinforcement layer to a heat treatment to obtain the linear reinforcement layer.
[0015] According to another aspect of this application, a magnetoresistive device is provided, including any of the magnetoresistive sensors described above, or a magnetoresistive sensor prepared using the method for preparing the magnetoresistive sensor described above.
[0016] Using the technical solution of this application, the magnetoresistive sensor includes a first electrode, a linear reinforcement layer, and a free layer stacked sequentially, wherein the material of the linear reinforcement layer includes a light metal and / or its oxide. Compared with the problem of low linearity and sensitivity caused by large hysteresis in existing magnetoresistive sensors, this application inserts a layer of light metal material and / or its oxide (i.e., a linear reinforcement layer) between the first electrode and the free layer, ensuring that the first electrode has a smaller impact on the free layer, improving the interface quality, ensuring small hysteresis, and thus ensuring high linearity and sensitivity of the magnetoresistive sensor. Attached Figure Description
[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:
[0018] Figure 1 A schematic diagram of the structure of a magnetoresistive sensor according to an embodiment of this application is shown;
[0019] Figure 2 A schematic diagram of another magnetoresistive sensor provided according to an embodiment of this application is shown.
[0020] The above figures include the following reference numerals:
[0021] 10. First electrode; 11. Linear reinforcement layer; 12. Free layer; 13. Barrier layer; 14. Fixed layer; 15. Second electrode; 16. Top electrode; 17. Bottom electrode. Detailed Implementation
[0022] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.
[0023] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0024] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element, or there may be an intermediate element present. Furthermore, in the specification and claims, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element, or "connected" to the other element via a third element.
[0025] As described in the background section, the large hysteresis of existing magnetoresistive sensors leads to low linearity and sensitivity. To address these issues, embodiments of this application provide a magnetoresistive sensor, a method for fabricating the magnetoresistive sensor, and a magnetoresistive device.
[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.
[0027] This application provides a magnetoresistive sensor, such as... Figure 1 and Figure 2 As shown, it includes:
[0028] First electrode 10;
[0029] A linear reinforcement layer 11 is located on the surface of the first electrode 10, and the material of the linear reinforcement layer 11 includes light metals and / or their oxides;
[0030] The free layer 12 is located on the surface of the linear reinforcement layer 11 that is away from the first electrode 10.
[0031] In this embodiment, the magnetoresistive sensor includes a first electrode, a linear reinforcement layer, and a free layer stacked sequentially. The linear reinforcement layer is made of a light metal and / or its oxide. Compared with the problem of low linearity and sensitivity caused by large hysteresis in existing magnetoresistive sensors, this application inserts a layer of light metal material and / or its oxide (i.e., a linear reinforcement layer) between the first electrode and the free layer. This ensures that the first electrode has a smaller impact on the free layer, improves the interface quality, and ensures small hysteresis, thereby ensuring high linearity and sensitivity of the magnetoresistive sensor.
[0032] Specifically, the aforementioned free layer is the sensing layer.
[0033] In one alternative embodiment, the thickness of the linear enhancement layer does not exceed 0.3 nm. In this embodiment, by controlling the thickness of the linear enhancement layer, hysteresis can be further reduced, thereby further improving the linearity and sensitivity of the magnetoresistive sensor.
[0034] According to some exemplary embodiments of this application, such as Figure 1 and Figure 2 As shown, the magnetoresistive sensor further includes: a barrier layer 13 located on the surface of the free layer 12 away from the linear enhancement layer 11; a fixed layer 14 located on the surface of the barrier layer 13 away from the free layer 12; and a second electrode 15 located on the surface of the fixed layer 14 away from the barrier layer 13. In this embodiment, by introducing a barrier layer between the free layer and the fixed layer, the magnetoresistive effect of the magnetic tunnel junction (MTJ) can be enhanced. The addition of the fixed layer helps to stabilize the magnetic field sensing direction of the magnetoresistive sensor, making the magnetization direction of the sensor more stable, further reducing hysteresis, and thus further improving the sensitivity and linearity of the magnetoresistive sensor.
[0035] Specifically, the aforementioned barrier layer is prepared by radio frequency sputtering and includes, but is not limited to, MgO, Al2O3, HfO2, MgAlO, and CuO, with a thickness of 0.5 nm to 3 nm. The aforementioned free layer includes at least one of Co, Fe, Ni, CoB, FeB, NiB, CoFe, NiFe, CoNi, and CoFeB, with a thickness of 1 nm to 5 nm; the aforementioned free layer includes at least one magnetic material or two magnetic materials separated by an insertion layer. The insertion layer is made of a non-magnetic material, such as Ta, W, Mo, and Ru, with a thickness of 0.1 nm to 0.5 nm. The aforementioned fixed layer includes, but is not limited to, a multilayer film structure formed by CoFeB and one of Co / Pt multilayer films, Co / Pd multilayer films, and Co / Ni multilayer films.
[0036] Specifically, the magnetic moment direction of the fixed layer is the first direction, and the magnetic moment direction of the free layer is the second direction, with the first direction intersecting the second direction.
[0037] In one embodiment, such as Figure 1 As shown, the magnetic moment direction of the fixed layer 14 is oriented outward (i.e., the first direction is parallel to the thickness of the first electrode 10), and the magnetic moment direction of the free layer 12 is oriented inward (i.e., the second direction is perpendicular to the thickness of the first electrode 10), and the magnetic moment direction of the free layer 12 will rotate with the magnetic field. In another embodiment, as... Figure 2 As shown, the magnetic moment direction of the fixed layer 14 is oriented in-plane (i.e., the first direction is perpendicular to the thickness of the first electrode 10), and the magnetic moment direction of the free layer 12 is oriented out-of-plane (i.e., the second direction is parallel to the thickness of the first electrode 10). This application does not impose specific limitations on the magnetic moment directions of the fixed layer and the free layer. The "plane" in in-plane and out-of-plane orientation refers to the surface of either the fixed layer or the free layer.
[0038] In other embodiments, the magnetoresistive sensor further includes an antiferromagnetic layer located between the fixed layer and the second electrode, wherein the antiferromagnetic layer is made of a manganese-based metal. In this embodiment, the antiferromagnetic layer can fix the magnetic moment direction of the fixed layer, making the magnetic moment direction of the fixed layer more stable.
[0039] According to some other exemplary embodiments of this application, the material of the linear enhancement layer includes Mg and / or Cu. In this embodiment, Mg and Cu, as light metals, can further reduce hysteresis and further improve the linearity and sensitivity of the magnetoresistive sensor.
[0040] In other embodiments, the magnetoresistive sensor further includes a magnetoresistive enhancement layer located between the linear enhancement layer and the free layer. The material of the magnetoresistive enhancement layer includes F(x) / Mg and / or F(x) / Cu, and element x includes at least one of the following: Li, Na and Ag.
[0041] Specifically, "F(x)" refers to a material or alloy containing element x. The " / " symbol in "F(x) / Mg" and "F(x) / Cu" usually indicates a combination or composite structure of two materials. That is, "F(x) / Mg" refers to a composite structure of a material containing element x and magnesium, and "F(x) / Cu" refers to a composite structure of a material containing element x and copper.
[0042] In other embodiments, such as Figure 1 As shown, the first electrode 10 is the top electrode 16, and the second electrode 15 is the bottom electrode 17.
[0043] In the above embodiments, the first electrode is the top electrode and the second electrode is the bottom electrode. During the fabrication of the magnetoresistive sensor, since the metal atoms of the linear enhancement layer have a low mass, the damage to the free layer is less. Furthermore, during the heavy metal sputtering process of the capping layer (i.e., the top electrode), the energy of the heavy metal in the capping layer mainly acts on the linear enhancement layer, which can better protect the free layer and improve the interface of the free layer, thereby achieving the effect of reducing hysteresis.
[0044] In some of the alternative solutions of this application, such as Figure 2 As shown, the first electrode 10 is the bottom electrode 17, and the second electrode 15 is the top electrode 16.
[0045] In the above embodiments, the first electrode is the bottom electrode, the second electrode is the top electrode, and the linear enhancement layer is deposited below the free layer. Because the atoms sputtered from it have low energy, they will not bombard the atoms of the bottom film (i.e., the bottom cell) to the surface during sputtering. On the contrary, it has a certain kinetic energy that will cause the atoms at the bottom to move on the surface, which has a certain repair effect on the interface, thereby making the interface smoother and improving the interface of the subsequent free layer, thereby achieving the effect of reducing hysteresis.
[0046] In some alternative embodiments of this application, the thickness of the linear enhancement layer is 0.1 nm to 0.3 nm. In this embodiment, by further controlling the thickness of the linear enhancement layer, hysteresis can be further reduced, thereby further improving the linearity and sensitivity of the magnetoresistive sensor.
[0047] Specifically, the thickness of the first electrode is 3nm to 40nm, the thickness of the second electrode is 3nm to 40nm, and the thickness of the fixing layer is 5nm to 10nm.
[0048] This application also provides a method for fabricating a magnetoresistive sensor, the method comprising the following steps:
[0049] Step S101: Provide the first electrode;
[0050] Step S102: A linear reinforcement layer is formed on the surface of the first electrode, wherein the material of the linear reinforcement layer includes a light metal and / or its oxide;
[0051] Step S103: A free layer is formed on the surface of the linear reinforcement layer away from the first electrode.
[0052] In this embodiment, a first electrode is first provided, then a linear reinforcement layer is formed on the surface of the first electrode, and finally a free layer is formed on the surface of the linear reinforcement layer away from the first electrode. The material of the linear reinforcement layer includes a light metal and / or its oxide. Compared with the problem of low linearity and sensitivity caused by large hysteresis in existing magnetoresistive sensors, this application inserts a layer of light metal material and / or its oxide (i.e., a linear reinforcement layer) between the first electrode and the free layer. This ensures that the first electrode has a smaller impact on the free layer, improves the interface quality, and ensures smaller hysteresis, thereby ensuring higher linearity and sensitivity of the magnetoresistive sensor.
[0053] According to some exemplary embodiments of this application, the first electrode is a bottom electrode, and forming a linear reinforcement layer on the surface of the first electrode includes: forming a preliminary linear reinforcement layer on the surface of the bottom electrode; performing an oxygen permeation treatment on the preliminary linear reinforcement layer to achieve oxidation; and performing a heat treatment on the oxidized preliminary linear reinforcement layer to obtain the linear reinforcement layer.
[0054] Specifically, deposition on the free layer Metallic Mg is oxidized by oxygen perfusion, followed by heat treatment at 300℃ for 20 minutes to obtain a linear reinforcement layer, wherein the oxygen perfusion time is 1cc2s.
[0055] In other embodiments, forming a free layer on the surface of the linear reinforcement layer away from the first electrode includes forming the free layer on the surface of the linear reinforcement layer away from the bottom electrode.
[0056] In other embodiments, after forming the free layer on the surface of the linear reinforcement layer away from the bottom electrode, the method further includes: forming a barrier layer on the surface of the free layer away from the bottom electrode; forming a fixed layer on the surface of the barrier layer away from the bottom electrode; and forming a top electrode on the surface of the fixed layer away from the bottom electrode.
[0057] Specifically, depositing light metals and / or their oxides on top of the free layer to protect it serves two purposes. First, because light metals have low atomic mass, their atoms have low energy during sputtering deposition, resulting in less bombardment of the free layer. Second, oxygen can be introduced into the free layer after sputtering, causing slight oxidation and reducing crystallization.
[0058] This application also provides a magnetoresistive device, including any of the magnetoresistive sensors described above, or a magnetoresistive sensor prepared using the above-described magnetoresistive sensor preparation method.
[0059] In the above embodiments, the magnetoresistive device includes a magnetoresistive sensor, which comprises a first electrode, a linear reinforcement layer, and a free layer stacked sequentially. The linear reinforcement layer is made of a light metal and / or its oxide. Compared to the problem of low linearity and sensitivity caused by large hysteresis in existing magnetoresistive sensors, this application inserts a layer of light metal material and / or its oxide (i.e., a linear reinforcement layer) between the first electrode and the free layer. This ensures that the first electrode has a smaller impact on the free layer, improves the interface quality, and ensures smaller hysteresis, thereby ensuring higher linearity and sensitivity of the magnetoresistive sensor, and thus ensuring higher linearity and sensitivity of the magnetoresistive device.
[0060] As can be seen from the above description, the embodiments of this application achieve the following technical effects:
[0061] 1) In the magnetoresistive sensor of this application, the magnetoresistive sensor includes a first electrode, a linear reinforcement layer, and a free layer stacked sequentially, wherein the material of the linear reinforcement layer includes a light metal and / or its oxide. Compared with the problem of low linearity and sensitivity caused by large hysteresis in existing magnetoresistive sensors, this application inserts a layer of light metal material and / or its oxide (i.e., a linear reinforcement layer) between the first electrode and the free layer, ensuring that the first electrode has a smaller impact on the free layer, improving the interface quality, ensuring small hysteresis, and thus ensuring high linearity and sensitivity of the magnetoresistive sensor.
[0062] 2) In the fabrication method of the magnetoresistive sensor of this application, a first electrode is first provided, then a linear reinforcement layer is formed on the surface of the first electrode, and finally a free layer is formed on the surface of the linear reinforcement layer away from the first electrode. The material of the linear reinforcement layer includes a light metal and / or its oxide. Compared with the problem of low linearity and sensitivity caused by large hysteresis in existing magnetoresistive sensors, this application inserts a layer of light metal material and / or its oxide (i.e., a linear reinforcement layer) between the first electrode and the free layer. This ensures that the first electrode has a smaller impact on the free layer, improves the interface quality, and ensures smaller hysteresis, thereby ensuring higher linearity and sensitivity of the magnetoresistive sensor.
[0063] 3) In the magnetoresistive device of this application, the magnetoresistive device includes a magnetoresistive sensor, which includes a first electrode, a linear reinforcement layer, and a free layer stacked sequentially. The linear reinforcement layer is made of a light metal and / or its oxide. Compared with the problem of low linearity and sensitivity caused by large hysteresis in existing magnetoresistive sensors, this application inserts a layer of light metal material and / or its oxide (i.e., a linear reinforcement layer) between the first electrode and the free layer. This ensures that the first electrode has a smaller impact on the free layer, improves the interface quality, and ensures smaller hysteresis, thereby ensuring higher linearity and sensitivity of the magnetoresistive sensor, and thus ensuring higher linearity and sensitivity of the magnetoresistive device.
[0064] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A magnetoresistive sensor, characterized in that, include: First electrode; A linear reinforcement layer is located on the surface of the first electrode, and the material of the linear reinforcement layer includes a light metal and / or its oxide; A free layer is located on the surface of the linear reinforcement layer away from the first electrode.
2. The magnetoresistive sensor according to claim 1, characterized in that, The thickness of the linear enhancement layer does not exceed 0.3 nm.
3. The magnetoresistive sensor according to claim 1, characterized in that, The magnetoresistive sensor also includes: A barrier layer is located on the surface of the free layer that is away from the linear reinforcement layer; A fixed layer is located on the surface of the barrier layer that is away from the free layer; The second electrode is located on the surface of the fixed layer away from the barrier layer.
4. The magnetoresistive sensor according to claim 1, characterized in that, The material of the linear reinforcement layer includes Mg and / or Cu.
5. The magnetoresistive sensor according to claim 3, characterized in that, The first electrode is the top electrode, and the second electrode is the bottom electrode.
6. The magnetoresistive sensor according to claim 3, characterized in that, The first electrode is the bottom electrode, and the second electrode is the top electrode.
7. The magnetoresistive sensor according to claim 2, characterized in that, The thickness of the linear enhancement layer is 0.1 nm to 0.3 nm.
8. A method for preparing a magnetoresistive sensor according to any one of claims 1 to 7, characterized in that, include: Provide the first electrode; A linear reinforcement layer is formed on the surface of the first electrode, the material of the linear reinforcement layer including light metals and / or their oxides; A free layer is formed on the surface of the linear reinforcement layer away from the first electrode.
9. The method for preparing a magnetoresistive sensor according to claim 8, characterized in that, The first electrode is a bottom electrode, and a linear reinforcement layer is formed on the surface of the first electrode, comprising: A pre-formed linear reinforcement layer is formed on the surface of the bottom electrode; The prepared linear reinforcement layer is subjected to oxygen permeation treatment to achieve oxidation; The oxidized pre-linear reinforcement layer is subjected to heat treatment to obtain the linear reinforcement layer.
10. A magnetoresistive device, characterized in that, It includes the magnetoresistive sensor according to any one of claims 1 to 7, or the magnetoresistive sensor prepared by the method of preparing the magnetoresistive sensor according to claim 8 or 9.