Vertical magnetoresistance sensor
By introducing a composite layer structure into the vertical magnetoresistive sensor, the vertical anisotropy of the interface is reduced, and the problem of low sensitivity of magnetoresistive sensors in the prior art is solved, thereby achieving higher sensitivity and thermal stability.
Patent Information
- Application Number
- CN202411886887.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-18
- Publication Date
- 2025-04-29
AI Technical Summary
When the existing magnetoresistive sensor detects the z-axis magnetic field, the free layer in the ground magnetization direction is in the plane has a large anisotropic field, and a large out-of-plane magnetic field is needed to pull it to rotate in the out-of-plane direction, resulting in low sensitivity.
By introducing a composite layer structure into the vertical magnetoresistive sensor, including a first ferromagnetic layer, a PMA enhancement layer and a second ferromagnetic layer, the sensing layer is used to reduce the vertical anisotropy of the interface and improve the sensitivity of the sensor.
While maintaining the perpendicular anisotropy of the interface, the sensitivity of the sensor is improved and the thermal stability of the sensing layer is enhanced.
Smart Images
Figure CN119902132A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of sensor technology, in particular to the field of magnetic sensor device technology, and specifically to a vertical magnetoresistive sensor. Background Art
[0002] Magneto-resistance sensors (e.g., giant magnetoresistance sensors and tunnel magnetoresistance sensors) are a new type of sensor that is widely used in consumer electronics, industrial electronics, and other fields. The sensor uses the fact that the resistance of a magnetic multilayer film changes with the size and angle of the magnetic field to detect the magnetic field. It has the advantages of high sensitivity, small size, and low power consumption.
[0003] In the prior art, one application scenario of magnetoresistive sensors is to detect the z-axis magnetic field, which is an alternative to Hall sensors. Figure 1 , the reference layer magnetization direction is usually fixed in the out-of-plane direction (z-axis). The free layer magnetization direction can rotate with the external magnetic field. In the ground state, the free layer magnetization orientation is in the in-plane direction (xy plane). Although this cross structure has z-axis sensitivity, the free layer has a large anisotropy field (H) because the ground state magnetization direction is in the plane. k ), a larger out-of-plane magnetic field is required to pull it to rotate out of the plane, so it is impossible to maintain a high sensitivity ( S is the sensitivity, M is the magnetization intensity, and R is the resistance of the perpendicular magnetoresistive sensor). Summary of the invention
[0004] The present invention provides a perpendicular magnetoresistive sensor, the purpose of which is to make it have higher sensitivity, so that the free layer can be pulled to rotate in the out-of-plane direction without a large out-of-plane magnetic field.
[0005] In order to solve at least one of the above problems existing in the prior art, the present application provides a vertical magnetoresistive sensor, comprising:
[0006] A reference layer; a magnetization direction perpendicular to the film surface of the perpendicular magnetoresistive sensor;
[0007] A spacer layer is disposed on the reference layer;
[0008] The sensing layer is laminated on the spacer layer, and its magnetization direction is parallel to the membrane surface; it includes at least one composite layer, and the composite layer includes a first ferromagnetic layer, a PMA enhancement layer and a second ferromagnetic layer laminated in sequence, and the sensing layer is used to reduce the perpendicular anisotropy of the interface in the perpendicular magnetoresistive sensor.
[0009] In some embodiments of the present application, the material of the PMA enhancement layer includes at least one of the following: MgO, HfO2 and CuO x ; or at least one of the following: Ta, Ir, Mo and W.
[0010] In some embodiments of the present application, a perpendicular magnetoresistive sensor further includes:
[0011] The fluoride layer is disposed on the PMA reinforcement layer; the material of the fluoride layer includes at least one of the following: LiF, MgO and LiF.
[0012] In some embodiments of the present application, the material of the reference layer includes at least one of the following: CoFeB, CoFe, NiFe and FeB.
[0013] In some embodiments of the present application, the material of the spacer layer includes at least one of the following: MgO, Al2O3, HfO2, MgAlO, CuO and Cu.
[0014] In some embodiments of the present application, the material of the first ferromagnetic layer and the material of the second ferromagnetic layer include a multi-element alloy consisting of at least one of the following: CoFe, NiFe and CoFeB.
[0015] In some embodiments of the present application, a perpendicular magnetoresistive sensor further includes:
[0016] A structural conversion layer is disposed on the reference layer;
[0017] The synthetic antiferromagnetic structure is arranged on the structural conversion layer.
[0018] In some embodiments of the present application, the material of the structural conversion layer includes at least one of the following: Mo, Ta, Ir and W; or a combination of at least one of Mo, Ta, Ir and W and a ferromagnetic material.
[0019] In some embodiments of the present application, the synthetic antiferromagnetic structure includes a first ferromagnetic structure, an antiferromagnetic coupling layer, and a second ferromagnetic structure that are sequentially arranged.
[0020] In some embodiments of the present application, the magnetization directions of the first ferromagnetic structure and the second ferromagnetic structure are opposite.
[0021] From the above description, it can be seen that a perpendicular magnetoresistive sensor provided in an embodiment of the present application includes: a reference layer; a magnetization direction perpendicular to the film surface of the perpendicular magnetoresistive sensor; a spacer layer, which is bonded to the reference layer; a sensing layer, which is bonded to the spacer layer, and the magnetization direction is parallel to the film surface; including at least one composite layer, the composite layer includes a first ferromagnetic layer, a PMA enhancement layer and a second ferromagnetic layer bonded in sequence, and the sensing layer is used for the perpendicular anisotropy of the interface in the perpendicular magnetoresistive sensor.
[0022] Firstly, the perpendicular magnetoresistive sensor provided by the present invention can further improve the sensitivity of the sensor while maintaining the perpendicular anisotropy of the interface. Secondly, the sensing layer of the perpendicular magnetoresistive sensor provided by the present invention has high thermal stability. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:
[0024] Figure 1 It is a schematic diagram of the structure of a magnetoresistive sensor in the prior art.
[0025] Figure 2 A schematic structural diagram of a perpendicular magnetoresistive sensor according to an embodiment of the present application.
[0026] Figure 3 This is a schematic diagram of the second structure of a perpendicular magnetoresistive sensor according to an embodiment of the present application.
[0027] Figure 4 This is a third structural schematic diagram of a perpendicular magnetoresistive sensor according to an embodiment of the present application.
[0028] Figure 5 This is a fourth structural schematic diagram of a perpendicular magnetoresistive sensor according to an embodiment of the present application. DETAILED DESCRIPTION
[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0030] It should be noted that the terms "including" and "having" in the specification and claims of the present application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. In the absence of conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.
[0031] The embodiment of the present application provides a vertical magnetoresistive sensor. Figure 2 A schematic diagram of a perpendicular magnetoresistive sensor according to an embodiment of the present application.
[0032] like Figure 2 As shown, a vertical magnetoresistive sensor comprises:
[0033] A reference layer; a magnetization direction perpendicular to the film surface of the perpendicular magnetoresistive sensor;
[0034] A spacer layer is disposed on the reference layer;
[0035] The sensing layer is laminated on the spacer layer, and its magnetization direction is parallel to the membrane surface; it includes at least one composite layer, and the composite layer includes a first ferromagnetic layer, a PMA enhancement layer and a second ferromagnetic layer laminated in sequence, and the sensing layer is used to reduce the perpendicular anisotropy of the interface in the perpendicular magnetoresistive sensor.
[0036] For perpendicular magnetoresistive sensors:
[0037]
[0038] Among them, K s is the interface anisotropy energy, M S To protect the magnetization intensity, t is the thickness.
[0039] In the prior art, the sensing layer usually uses a thicker layer of ferromagnetic metal to keep its magnetic moment direction in the plane. s is smaller and t is larger, so Can be ignored.
[0040] In contrast, the present invention inserts a thinner (0.1-0.8 nm) layer of oxides such as MgO or heavy metals such as Ta, Ir, and Mo into the sensing device in the prior art to increase the perpendicular magnetic anisotropy (PMA) of the interface and reduce the thickness t of the single layer, so that Increase, achieve |Hk | is reduced to achieve an improvement in the sensitivity of the vertical magnetoresistive sensor.
[0041] From the above description, it can be seen that the present application provides a vertical magnetoresistive sensor, including: a reference layer; a magnetization direction perpendicular to the film surface of the vertical magnetoresistive sensor; a spacer layer, which is attached to the reference layer; a sensing layer, which is attached to the spacer layer, and the magnetization direction is parallel to the film surface; including at least one composite layer, the composite layer includes a first ferromagnetic layer, a PMA enhancement layer and a second ferromagnetic layer which are attached in sequence, and the sensing layer is used to reduce the vertical anisotropy of the interface in the vertical magnetoresistive sensor. The present invention has the following beneficial effects:
[0042] Firstly, the perpendicular magnetoresistive sensor provided by the present invention can further improve the sensitivity of the sensor while maintaining the perpendicular anisotropy of the interface. Secondly, the sensing layer of the perpendicular magnetoresistive sensor provided by the present invention has high thermal stability.
[0043] In some embodiments of the present application, the material of the PMA enhancement layer includes at least one of the following: MgO, HfO2 and CuO x ; or at least one of the following: Ta, Ir, Mo and W.
[0044] Specifically, multiple composite layers in the sensing layer are laminated in sequence, and a thin layer (0.1-0.8 nm) of metal oxide (MgO, HfO2, etc.) or heavy metal (Ta, Ir, W, Mo, etc.) is inserted into each composite layer.
[0045] In some embodiments of the present application, a perpendicular magnetoresistive sensor further includes:
[0046] The fluoride layer is disposed on the PMA reinforcement layer; the material of the fluoride layer includes at least one of the following: LiF, MgO and LiF.
[0047] Specifically, the PMA reinforcement layer may be combined with fluoride as a composite insertion layer. Preferably, the material of the fluoride includes at least one of the following: LiF, MgO and LiF.
[0048] In some embodiments of the present application, the material of the reference layer includes at least one of the following: CoFeB, CoFe, NiFe and FeB.
[0049] Specifically, the magnetic reference layer can be made of materials such as CoFeB, CoFe, NiFe, FeB, etc., with a thickness between 0.5nm and 2nm.
[0050] In some embodiments of the present application, the material of the spacer layer includes at least one of the following: MgO, Al2O3, HfO2, MgAlO, CuO and Cu.
[0051] Specifically, the spacer layer can be made of materials such as MgO, Al2O3, HfO2, MgAlO, CuO, Cu, etc., with a thickness between 0.5-3nm.
[0052] In some embodiments of the present application, the material of the first ferromagnetic layer and the material of the second ferromagnetic layer include a multi-element alloy consisting of at least one of the following: CoFe, NiFe and CoFeB.
[0053] Specifically, the material of the first ferromagnetic layer and the material of the second ferromagnetic layer are multi-element alloys composed of one or more elements such as CoFe, NiFe, CoFeB, etc., and the thickness is between 2-5 nm.
[0054] In some embodiments of the present application, see Figure 3 , a perpendicular magnetoresistive sensor, further comprising:
[0055] A structural conversion layer is disposed on the reference layer;
[0056] The synthetic antiferromagnetic structure is arranged on the structural conversion layer, and is close to the reference layer and far away from the spacing layer.
[0057] In some embodiments of the present application, the material of the structural conversion layer includes at least one of the following: Mo, Ta, Ir and W; or a combination of at least one of Mo, Ta, Ir and W and a ferromagnetic material.
[0058] Specifically, the structural conversion layer is a combination of one or more materials such as Mo, Ta, Ir, W, or a combination of the above materials and ferromagnetic materials, such as W / Co, and has a thickness of less than 2 nm.
[0059] In some embodiments of the present application, the synthetic antiferromagnetic structure includes a first ferromagnetic structure, an antiferromagnetic coupling layer, and a second ferromagnetic structure that are sequentially arranged. The magnetization directions of the first ferromagnetic structure and the second ferromagnetic structure are opposite.
[0060] Specifically, see Figure 3 The synthetic antiferromagnetic structure includes, from bottom to top, a first ferromagnetic structure (P1), an antiferromagnetic coupling layer and a second ferromagnetic structure (P2), for example, [Co 0.3nm / Pt 0.5nm]m / Ru0.8nm / [Co 0.3nm / Pt0.5nm]n.
[0061] Here, taking the CoFeB 3nm structure as an example, various parameters of the vertical magnetoresistive sensor provided in this application are shown in Table 1.
[0062] Table 1
[0063]
[0064] In some embodiments of the present application, see Figure 4 When the number of composite layers is multiple, that is, in order to further improve the sensitivity, a multi-insertion layer structure is adopted for sensing, there are multiple PMA enhancement layers, and the thickness of a single insertion layer is between 0.1-0.8nm.
[0065] In the above structure, it can be repeated insertion of a single oxide PMA reinforcement layer such as MgO; it can also be repeated insertion of a metal PMA reinforcement layer such as Ta; it can also be repeated insertion of an alternating structure of oxide and metal; it can also be multiple insertions of an interface PMA reinforcement layer and a PMA reinforcement layer as a composite insertion layer.
[0066] In some embodiments of the present application, see Figure 5 , and also provides a vertical magnetoresistive sensor with a top pinning structure. From bottom to top, it includes: a sensing layer, a spacing layer, a reference layer, a structural conversion layer, and a synthetic antiferromagnetic structure (artificial synthetic antiferromagnetic structure).
[0067] From the above description, it can be seen that a perpendicular magnetoresistive sensor provided by the present application includes: a reference layer; a magnetization direction perpendicular to the film surface of the perpendicular magnetoresistive sensor; a spacer layer, which is bonded to the reference layer; a sensing layer, which is bonded to the spacer layer and has a magnetization direction parallel to the film surface; including at least one composite layer, the composite layer includes a first ferromagnetic layer, a PMA enhancement layer and a second ferromagnetic layer bonded in sequence, and the sensing layer is used for the perpendicular anisotropy of the interface in the perpendicular magnetoresistive sensor.
[0068] Firstly, the perpendicular magnetoresistive sensor provided by the present invention can further improve the sensitivity of the sensor while maintaining the perpendicular anisotropy of the interface. Secondly, the sensing layer of the perpendicular magnetoresistive sensor provided by the present invention has high thermal stability.
[0069] In the description of this specification, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.
[0070] The descriptions with reference to the terms "one embodiment", "a specific embodiment", "some embodiments", "for example", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. The order of steps involved in each embodiment is used to schematically illustrate the implementation of the present invention, and the order of steps therein is not limited and may be appropriately adjusted as needed.
[0071] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.
[0072] Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. In the description of this specification, the description of the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of this specification. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, in the absence of contradiction, a person skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.
[0073] The above is only an example of the embodiment of the present specification and is not intended to limit the embodiment of the present specification. For those skilled in the art, the embodiment of the present specification may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiment of the present specification shall be included in the scope of the claims of the embodiment of the present specification.
Claims
1. A vertical magnetoresistive sensor, characterized in that: include: Reference layer; The magnetization direction is perpendicular to the film surface of the perpendicular magnetoresistive sensor; A spacer layer is disposed on the reference layer; A sensing layer is disposed on the spacer layer, and its magnetization direction is parallel to the film surface; It comprises at least one composite layer, wherein the composite layer comprises a first ferromagnetic layer, a PMA enhancement layer and a second ferromagnetic layer which are sequentially arranged, and the sensing layer is used to reduce the perpendicular anisotropy of the interface in the perpendicular magnetoresistive sensor.
2. The perpendicular magnetoresistive sensor according to claim 1, characterized in that: The material of the PMA enhancement layer includes at least one of the following: MgO, HfO2 and CuO x ; or at least one of the following: Ta, Ir, Mo and W.
3. The perpendicular magnetoresistive sensor according to claim 1, characterized in that: Also includes: A fluoride layer is laminated on the PMA reinforcement layer; The material of the fluoride layer includes at least one of the following: LiF, MgO and LiF.
4. The perpendicular magnetoresistive sensor according to claim 1, characterized in that: The material of the reference layer includes at least one of the following: CoFeB, CoFe, NiFe and FeB.
5. The perpendicular magnetoresistive sensor according to claim 1, characterized in that: The material of the spacer layer includes at least one of the following: MgO, Al2O3, HfO2, MgAlO, CuO and Cu.
6. The perpendicular magnetoresistive sensor according to claim 1, characterized in that: The material of the first ferromagnetic layer and the material of the second ferromagnetic layer include a multi-element alloy consisting of at least one of the following: CoFe, NiFe and CoFeB.
7. The perpendicular magnetoresistive sensor according to any one of claims 1 to 6, characterized in that: Also includes: A structural conversion layer is disposed on the reference layer; The synthetic antiferromagnetic structure is arranged on the structural conversion layer.
8. The perpendicular magnetoresistive sensor according to claim 7, characterized in that: The material of the structural conversion layer includes at least one of the following: Mo, Ta, Ir and W; or a combination of at least one of Mo, Ta, Ir and W and a ferromagnetic material.
9. The perpendicular magnetoresistive sensor according to claim 7, characterized in that: The synthetic antiferromagnetic structure includes a first ferromagnetic structure, an antiferromagnetic coupling layer and a second ferromagnetic structure which are sequentially arranged.
10. The perpendicular magnetoresistive sensor according to claim 9, characterized in that: The first ferromagnetic structure and the second ferromagnetic structure have opposite magnetization directions.