Magnetic sensitive bridge resistor component with pma layer structure and bridge circuit and method of manufacturing thereof

Abstract

This disclosure relates to a magnetically sensitive bridge resistor assembly (20) having at least two adjacent bridge resistors (14) disposed on a substrate (12) for magnetic sensitivity along the principal axis direction (SA). Each bridge resistor (14) includes a series circuit of multiple TMR layer structures (22, 70, 72). Each TMR layer structure (22, 70, 72) includes an antiferromagnetic layer (24), at least one first fixed ferromagnetic layer (26), and a free ferromagnetic layer (30). The first fixed ferromagnetic layer has a first fixed magnetization direction (28) substantially along the principal axis direction (SA) and located in the plane of the TMR layer structure (22, 70, 72). The free ferromagnetic layer has a free magnetization direction (32). A nonmagnetic interlayer (34) is disposed between the free ferromagnetic layer (30) and at least one first fixed ferromagnetic layer (26). Here it is proposed that, in the absence of a magnetic field, the free magnetization direction (32) is perpendicular to the plane orientation of the TMR layer structures (22, 70, 72) to form a PMA (perpendicular magnetic anisotropy) layer structure, and the first fixed magnetization direction (28) of the TMR layer structures (22, 70, 72) adjacently disposed on the substrate (12) of the bridge resistor (14) is different from each other. For this purpose, in manufacturing, a temperature of at least 260°C to a maximum of 350°C is used for a duration of at least 1 hour to a maximum of 12 hours, and a field strength of a pre-processing magnetic field (Hz) with a magnetic flux density of less than 500 mT is used for the coupled input. In a parallel aspect, a bridge circuit for measuring weak magnetic fields and a method for manufacturing a bridge resistor assembly (20) are proposed.

Description

Technical Field

[0001] This disclosure relates to a magnetically sensitive bridge resistor assembly comprising at least two adjacent TMR bridge resistors magnetically sensitive along the principal axis direction disposed on a substrate. The disclosure also relates to such bridge circuits, particularly for use in current sensors or angle sensors, preferably for vector measurement of weak magnetic fields up to 50 mT. In the TMR layer structure of the bridge resistor assembly, the free magnetization direction of the free ferromagnetic layer is perpendicular to a first fixed magnetization direction and the plane orientation of the TMR layer structure in the absence of a magnetic field, forming a perpendicular magnetic anisotropy (PMA) layer structure.

[0002] In one parallel aspect, this disclosure relates to such a bridge resistor assembly and a method of manufacturing such a bridge circuit. Background Technology

[0003] Magnetoresistive magnetic field sensors are used to measure magnetic fields based on resistance. With appropriate geometric arrangements, other physical quantities, such as displacement, angle, or current intensity, can be detected. Magnetoresistive magnetic field sensors are based on the magnetoresistive effect. The magnetoresistive effect describes the change in the resistance of a material due to the application or change of an external field. The magnetoresistive effect can be expressed by the change in resistance (ΔR = R). max -R min ) and minimum resistance value R min In terms of quotient, magnetic field sensors with high magnetoresistance are based on the giant magnetoresistance (GMR) effect or the tunnel magnetoresistance (TMR) effect. Alternatively, materials exhibiting the anisotropic magnetoresistance (AMR) effect may also exist. These effects are collectively referred to as xMR effects.

[0004] TMR magnetic field sensors comprise thin-layer structures made of non-magnetic and magnetic materials in a layered structure, where magnetic coupling or spin effects influence resistance across the layers. In TMR-based magnetoresistive layered structures, resistance can change by up to 600% based on an external field. Here, a layered structure refers to a structure that can be described as a sequence of thin layers on an axis typically perpendicular to the substrate surface, while having a geometry on another axis orthogonal to this axis.

[0005] To fabricate a TMR magnetic field sensor, a layer structure is formed within the TMR layer structure, consisting of at least two ferromagnetic layers and an insulating layer that serves as a tunneling barrier and also as an intermediate layer, allowing tunneling current to flow between the two ferromagnetic layers. In the case of a TMR magnetic field sensor, the insulating layer is typically composed of Al₂O₃ or MgO. Besides geometric parameters such as area, the resistance of the tunneling element also depends on how the two ferromagnetic layers are magnetized relative to each other. If the two ferromagnetic layers are magnetized parallel to each other, the resistance R... Min Minimum. If two ferromagnetic layers are magnetized antiparallel to each other, the resistance R is minimized. Max maximum.

[0006] In practice, the magnetization direction of one of the two ferromagnetic layers is typically fixed or pinned so that the magnetization of this layer does not respond to an external field, or only weakly. This layer is called the reference layer, or pinned layer. Below, the reference layer should be referred to as the first fixed ferromagnetic layer. Conversely, the other layer is designed so that its magnetization follows an external field in a deterministic manner. This layer is also called the detection layer, or free ferromagnetic layer. Below, the detection layer is referred to as the free ferromagnetic layer.

[0007] Thin-film technology can be used to fabricate such structures or resistive elements. Within the scope of the manufacturing method, the magnetization direction of a fixed ferromagnetic layer can be permanently set; this is commonly referred to as "pinning." To achieve pinning of the fixed ferromagnetic layer, the ferromagnetic layer is typically coupled to an antiferromagnetic adjacent layer. To set the magnetization direction, the resistive element, i.e., the layer structure, is heated to a so-called "blocking temperature." At this blocking temperature, the exchange coupling between the antiferromagnetic layer and the ferromagnetic layer disappears; typically, this blocking temperature is below the Curie temperature of the ferromagnetic layer. After reaching a desired temperature above the blocking temperature but below the Curie temperature, an external pinning magnetic field is applied to the ferromagnetic layer, thereby forcing the ferromagnetic layer into a defined magnetization direction. For this to be necessary, the applied pinning magnetic field must be sufficient to orient the ferromagnetic layer completely parallel to the pinning field direction. When the layer structure recools below the blocking temperature under the applied pinning magnetic field, the magnetization direction remains unchanged.

[0008] In this context, the pinning magnetic field discussed below refers to a locally acting magnetic field that penetrates the ferromagnetic layers of the layered structure perpendicular to the desired pinning direction, i.e., tangentially to the substrate surface, forming a local magnetic field component. This is distinct from the so-called pretreatment magnetic field, which is a globally oriented magnetic field derived from the oriented magnetic field by means of a guiding magnetic field, for example, by means of ferromagnetic structuring elements. The globally pretreatment magnetic field is typically stronger and can be oriented in a different direction than the local pinning magnetic field.

[0009] To determine the pinning direction, it is known that selective local heating methods can be used. This involves selectively heating a spatially defined area on the substrate carrying the layer structure using a selective heating method, particularly laser heating, and applying an external magnetic field parallel to the substrate surface in the desired direction for pinning. This allows for pinning locally heated areas with layer structures in the same direction. If different pinning directions are to be established on the substrate, the method must be repeated multiple times with different external magnetic field orientations; however, it is not possible to pin spatially adjacent layer structures in different directions. On the other hand, the construction of typical direction-selective magnetic field sensors requires layer structures with different preferred orientations but the same process technology characteristics. Therefore, it is desirable to pin closely adjacent layer structures in different directions.

[0010] Furthermore, for antiferromagnetic materials, such as PtMn or NiMn, which may recrystallize into the L10 antiferromagnetic ordered phase during pinning, laser pinning of less than one second is disadvantageous. The recrystallization process typically lasts for several hours and is practically impossible to achieve through localized laser heating.

[0011] A method and apparatus for multipinning a magnetic field sensor are known from WO 2016 / 078793 A1, in which soft magnetic structured elements are arranged adjacent to a layer structure, and the structured elements couple a pre-processed magnetic field into the layer structure. The method proposed in this document allows the pre-processed magnetic field to be coupled into the substrate surface perpendicularly, thereby enabling arbitrary pinning directions tangentially to the substrate surface in the sense of multi-directional pinning. This multi-directional pinning can, for example, produce high-precision angle sensors with harmonic filtering capabilities for sensor signals, such as the angle sensor described in WO 2016 / 083420 A1. However, in practical applications, this method can only achieve small pinning magnetic flux densities in the range far below 1T, therefore this method cannot be used for multilayer stacked structures with strong magnetic coupling.

[0012] By dividing the device into a fixed ferromagnetic layer (i.e., a reference layer) and a free ferromagnetic layer (i.e., a detection layer) that responds differently to external fields, it is possible to obtain the resistance change when the external field changes, thus realizing a sensing device. The resistance correlation is related to the angle between the magnetization direction of the free layer and the magnetization direction of the fixed ferromagnetic layer, also known as the pinned layer.

[0013] The disadvantage of a layer structure with only one fixed ferromagnetic layer, also known as a "simple spin valve (SSV)," is its low thermal stability. Specifically, there is a risk that the pinning direction may rotate due to high temperatures and strong magnetic fields during application. This effect causes drift in the behavior of sensors using these reference layers. It is applicable here that the smaller the magnetic moment of the reference layer, the weaker the coupling input of the magnetic field and the rotation of the layer. Therefore, it is advantageous to keep the reference layer thickness small, thereby minimizing the potential drift. However, in this SSV structure, the magnetoresistance effect is relatively small. The advantage, however, is that only a small magnetic field strength is required for the orientation of the reference layer.

[0014] In an improved reference layer structure, a first fixed ferromagnetic layer is attached to an antiferromagnetic layer, and a second fixed ferromagnetic layer is also provided. A coupling layer is provided between these two fixed ferromagnetic layers, which enables antiparallel RKKY coupling (Ruderman-Kittel-Kasuya-Yoshida interaction) between the two ferromagnetic layers. This layer structure is also known as an "antiparallel coupled pinned layer spin valve (APP-SV)" or an "artificial antiferromagnet." Because the magnetic moments of the two fixed ferromagnetic layers are approximately equal and the total magnetic moment of the ferromagnetic layers cancels out to approximately zero due to antiparallel orientation, during operation, an external magnetic field causes only a small change in the magnetization direction of the reference layer system, thus making this APP-SV stable even at high temperatures. Furthermore, compared to SSV, APP-SV exhibits a greater magnetoresistance effect.

[0015] However, a major drawback is that, because the magnetic moments of the two fixed ferromagnetic layers cancel each other out (the total magnetic moment is approximately zero), this layer structure can only be pinned if the magnetic flux density is sufficient to overcome the RKKY coupling between the fixed ferromagnetic layers. This requires a magnetic flux density greater than 1 T. This necessitates high costs for the pinning process. Magnetic field sensors with multiple stacks of layers or resistive elements that should have different magnetic orientations are simply impossible to manufacture, or can only be manufactured at extremely high costs.

[0016] In the absence of a magnetic field, a magnetization direction is typically established in a free ferromagnetic layer. This magnetization direction lies within the layer plane, and to close the magnetic circuit, it is usually oriented antiparallel to the magnetization direction of the fixed ferromagnetic layer. The characteristics of the magnetization direction established in the free layer are largely determined by the anisotropy of the material thickness and geometry, particularly the layer shape.

[0017] The in-plane magnetization orientation of the free layer limits the linearity and dynamic range of the magnetic field strength to be measured, and restricts the accuracy in angle measurements, or requires extremely high layer orientation accuracy, which is therefore disadvantageous. In many sensor applications, especially in angle measurement tasks, it is necessary to arrange TMR layer structures with different in-plane magnetization orientations in the free layer on different chip substrates. This requires at least two independent chip substrates to interconnect into a sensor bridge circuit, which must be oriented and interconnected at a predetermined angle, significantly increasing space requirements and manufacturing costs. The bonding wires required for this purpose increase the susceptibility to errors during assembly and are susceptible to capacitive and inductive errors. Furthermore, the spatial separation of the layer structures on different chip substrates introduces greater deviations and tolerances.

[0018] In DE 10 2019 107 689 A1, a LAPP layer structure (a lever-type antiparallel coupled pinned spin valve layer structure—an artificial antiferromagnet) is known, which has a horizontal magnetization direction in both the fixed and free layers. The pinning procedure is described, requiring heating above the blocking temperature, and it is proposed that pinning be performed for any length of time under low magnetic field strength. The duration should be at least 1 hour, preferably at least 5 hours, and particularly at least 12 hours, with no upper time limit. This document teaches the horizontal orientation of the free magnetization but not the vertical PMA orientation of the free layer.

[0019] Another document, US 2015 / 0 137 292 A1, discloses a magnetic tunnel junction (MTJ) layer structure with a thin free sensing layer having a vertical magnetization direction and a horizontally magnetized reference layer fixed by pinning layers. The annealing process is performed at 300°C for 2 hours. Neither adjacent layer structures with antiparallel orientations in the reference layer nor combined annealing and pinning steps are discussed here.

[0020] A layer structure similar to US2015 / 0137292A1 is known from DE 10 2020 200 177 A1 and DE 10 2020 114 551 A1, which has a vertically magnetized free PMA layer and an antiparallel horizontally magnetized artificial antiferromagnet, wherein no details are given about the manufacturing method, in particular the temperature, duration, and pre-magnetizing field.

[0021] A similar layer structure is described in US2012 / 0261777A1, in which both the free and pinned layers are vertically oriented. The free layers are crystallized (annealed) at 250°C, and the pinned layers lose their vertical magnetization at temperatures above 200°C. An annealing temperature of 350°C can be used for one hour to allow all layers to crystallize. Neither adjacent, antiparallel pinned layers are mentioned here, all magnetization is perpendicular to the layer plane, and the duration and combination of pinning and annealing mentioned in that document differ significantly from the relevant content of this disclosure.

[0022] US2014 / 0175581A1 also describes the vertically oriented magnetization of the free layer and pinned layer, and specifies an annealing temperature of 250°C. The remaining cases are governed by the provisions already described in US2012 / 0261777A1.

[0023] US2014 / 0084398A1 generally specifies an annealing step for the PMA layer at a temperature of 300-350°C, but only a single pinning layer is provided here. Therefore, this document does not exceed the disclosure of US2014 / 0175581A1.

[0024] DE 10 2021 110 733 A1 does not mention the specific layer structure construction and the specifications of the layer structure according to this disclosure, and only describes the serpentine and nested arrangement of the TMR layer structure for each bridge resistor.

[0025] The aforementioned literature does not mention the specific process conditions for pinning adjacent, antiparallel oriented layer structures, and at most describes the isolated features of the annealing step used to adjust the orientation of the thin free layer, without proposing a combined configuration scheme of LAPP structure and PMA orientation achieved by combining appropriate process parameters. Summary of the Invention

[0026] The purpose of this disclosure is to provide a magnetic bridge resistor assembly for a magnetically sensitive magnetic field sensor, a magnetic bridge circuit, and a method for manufacturing a magnetic bridge resistor assembly for a magnetic field sensor, which are improvements over the prior art.

[0027] In particular, introducing perpendicular magnetic anisotropy (PMA) into TMR sensors helps increase the measurable magnetic field range from hundreds of Oe to thousands of Oe, or from tens of mT to hundreds of mT. Furthermore, even for angle measurement tasks, it is desirable to integrate all TMR layer structures onto a common chip substrate. The sensor architecture sought here can bridge the gap in the trade-offs between sensitivity and magnetic field range between established TMR-based and Hall effect-based sensors. By aligning the PMA, which is dominated by magnetization in the free layer in the absence of a magnetic field, the preferred magnetic axis of the free layer can be oriented out-of-plane (OOP), while the preferred magnetic axis of the fixed layer is in-plane (IP). This aims to reduce magnetic anisotropy errors and increase the measurable magnetic field range.

[0028] The stated objective is achieved by the bridge resistor assembly, bridge circuit, and related manufacturing methods according to the independent claims. Advantageous configurations of this disclosure are the subject of the dependent claims.

[0029] According to this disclosure, a magnetically sensitive bridge resistor assembly is proposed, comprising at least two adjacent bridge resistors disposed on a substrate for magnetically sensing a bridge circuit along the principal axis direction SA. Each bridge resistor includes a series circuit of multiple TMR layer structures. Each TMR layer structure includes an antiferromagnetic layer, at least one first fixed ferromagnetic layer, and a free ferromagnetic layer. The first fixed ferromagnetic layer has a first fixed magnetization direction substantially along the principal axis direction SA and located in the plane of the TMR layer structure. Exchange coupling exists between the antiferromagnetic layer and the first fixed ferromagnetic layer. The free ferromagnetic layer has a free magnetization direction. A nonmagnetic interlayer is disposed between the free ferromagnetic layer and the at least one first fixed ferromagnetic layer, such that the resistance characteristics of the bridge resistor assembly depend on the first fixed magnetization direction and the externally measured magnetic field H. ext The angular deviation between the free magnetization directions.

[0030] According to this disclosure, in the absence of a magnetic field, the free magnetization direction is perpendicular to the first fixed magnetization direction and perpendicular to the plane orientation of the TMR layer structure, that is, oriented out of plane and perpendicular to the layer plane, in order to form a PMA layer structure (perpendicular magnetic anisotropy), and the first fixed magnetization directions of the TMR layer structures of the at least two bridge resistors disposed adjacently on the substrate are different from each other, in particular oriented substantially 180° opposite to each other.

[0031] Furthermore, according to this disclosure, the free ferromagnetic layer is annealed in a free magnetization direction for forming the PMA layer structure at a temperature of at least 260°C to a maximum of 350°C, for a duration of at least 1 hour to a maximum of 12 hours, and under a predeterminable field strength of a pre-processed magnetic field with a magnetic flux density of less than 500 mT, and the first fixed ferromagnetic layer is pinned in a combination of different first fixed magnetization directions for forming adjacent bridge resistors.

[0032] In other words, an arrangement of adjacent bridge resistors is proposed, wherein the bridge resistors have PMA orientation and simple-spin-valve structure or APP / LAPP structure, that is, a combination of synthetic antiferromagnets with fixed ferromagnetic layers. The PMA orientation has a free layer on the plane of the layer structure with a magnetic field orientation perpendicular to the magnetic field in the absence of a magnetic field. The fixed ferromagnetic layers therein have different fixed magnetic field orientations in the principal axis direction SA within the layer plane, especially magnetic field orientations that are 180° apart.

[0033] Within the scope of this disclosure, a combination of annealing and pinning processes that can be performed simultaneously in time is proposed: the annealing process is used to generate a PMA orientation in the free ferromagnetic layer, perpendicular to the layer plane of the layer structure, by fabricating the desired crystal structure, or to "anneal" the crystal structure in this way. The pinning process is used to fix a fixed magnetization direction in the one or more of the fixed ferromagnetic layers in a predetermined direction within the layer structure plane, which is achieved by anchoring the magnetization direction of the ferromagnetic layer by means of coupling to an antiferromagnetic layer. The annealing process for providing the PMA orientation of the free ferromagnetic layer and the pinning process for fixing the magnetization in the fixed ferromagnetic layer are performed simultaneously in time, in combination, under the same temperature and time specifications.

[0034] This disclosure teaches a precise combination of annealing and pinning conditions in terms of time, temperature, and pretreatment magnetic field strength, which should be selected such that: - This forms a stable PMA. - It also forms a strong artificial antiferromagnetic material with a fixed layer.

[0035] This combination was only recognized through long and arduous development work and is not obvious from the prior art because those skilled in the art cannot derive the inspiration to combine these individual features in this way. In particular, the prior art does not teach a process time window with an annealing process duration of no more than 12 hours or less.

[0036] The proposed bridge resistor assembly achieves a series of advantages: Introducing PMA orientation into the free ferromagnetic layer enables the provision of a high dynamic measurement field range while maintaining high thermal stability. In existing in-plane orientation techniques, the measurement range is hampered by a high magnetic anisotropy field Hk, which characterizes the effect of free rotation of magnetization in the free layer. This work shows that by providing PMA orientation, the measurement range can be extended by at least four to five times, reaching a range previously only achievable with Hall sensors. The bridge resistor assembly is advantageously suited for measuring weak fields up to 100 mT, preferably up to 30 mT or 300 Oe, where measurements up to 100 mT and higher can be performed with high linearity.

[0037] The PMA layer structure allows for linearization of the measurement range characteristic curve over a high measurement range, which is impossible with in-plane oriented layer structures to date. Hysteresis-free characteristic curves can be achieved, particularly in the field range up to 100 mT. The temperature-dependent slope characteristic curve behavior is also significantly improved, making the sensor temperature-insensitive over a wide range. The temperature-slope characteristic curve describes the signal behavior—sensitivity versus temperature change—expressed as a percentage, where the TC_Slope eigenvalue characterizes the gradient of the temperature-slope characteristic curve. Furthermore, in the PMA layer structure with a free ferromagnetic layer, the shape of the free layer is no longer the dominant factor. In contrast to in-plane layer structures where shape anisotropy dominates, the shape design of the TMR resistive element is freely selectable. Consequently, due to its lower geometric requirements, the PMA layer structure can be manufactured more advantageously, particularly with the cost advantage of significantly reducing the free layer thickness from, for example, greater than 50 nm in in-plane layer structures to approximately 1 nm or less. Integrating all TMR layer structures onto a single common chip substrate due to the possibility of multiple pinning eliminates the need for bonding connections between different chip substrates to form the sensor fabrication. The spatial proximity of the layers results in lower manufacturing errors, reduced layer misalignment, and improved signal quality. Finally, PMA layer structures can also be used to measure so-called out-of-plane (OOP) fields, making them particularly advantageous over 2D in-plane layer structures, especially in space-constrained 3D measurement tasks.

[0038] By setting different pinning directions for adjacent TMR layer structures, effective harmonic filtering can be achieved to reduce field strength-related angle errors in angle sensors. Due to the multi-pinning capability, integrating all layer structures onto a common chip substrate for all sensor tasks, especially angle measurement, allows for the integration of the entire sensor with low component tolerances. Finally, through the same PMA orientation of the free ferromagnetic layers, all TMR layer structures for the sensor bridge circuitry can be provided on a single common chip substrate. The free magnetic layers are not coupled to other layers in the TMR layer system.

[0039] In a favorable improvement, a coupling layer and a second fixed ferromagnetic layer can be disposed between the first fixed ferromagnetic layer and the intermediate layer to form an APP or LAPP layer structure (a (lever-type) antiparallel coupled pinned layer spin valve layer structure—an artificial antiferromagnet). The LAPP layer structure is a subset of the APP layer structure and has a different magnetic moment from the fixed ferromagnetic layer. If the APP / LAPP layer structure with a reference layer is used instead of the SSV layer structure, a second fixed ferromagnetic layer, typically with opposite magnetization directions, exists in addition to the first fixed ferromagnetic layer. Both orientations lie within the plane. The magnetization direction of the free magnetic layer is perpendicular to this plane, i.e., it has a PMA orientation.

[0040] In an advantageous improvement of the above embodiments, the first fixed ferromagnetic layer may have a first magnetic moment, and the second fixed ferromagnetic layer may have a second magnetic moment of the APP / LAPP layer structure. Preferably, the quotient of the first magnetic moment and the second magnetic moment of each LAPP structure may not be equal to 1, particularly between 1.3 and 2.3, preferably 1.6. This results in a (lever-type) antiparallel coupled pinned spin valve layer, i.e., the so-called LAPP layer structure. Furthermore, the material composition and / or layer thickness of the first and second fixed ferromagnetic layers are preferably different. In this improvement, it is proposed that the quotient of the first magnetic moment of the first fixed ferromagnetic layer coupled to the antiferromagnetic layer and the second magnetic moment of the second fixed ferromagnetic layer antiparallel to the first ferromagnetic layer is between 1.3 and 2.3, preferably 1.6. Thus, the first fixed ferromagnetic layer coupled to the antiferromagnetic layer through exchange coupling has approximately twice the magnetic moment of the second fixed ferromagnetic layer, which is located on the side of the first fixed ferromagnetic layer opposite to the antiferromagnetic layer and antiparallel to the first fixed ferromagnetic layer through a non-magnetic coupling layer. Thus, the antiferromagnetic layer, the first and second fixed ferromagnetic layers, and the coupling layer form a reference layer stack that can be pinned under very low magnetic field strength. The total magnetic moment M_APP_SV generated by the two ferromagnetic layers MFM1 and MFM2 of the layer structure is obtained by the following equation: M_APP_SV=MFM1–MFM2 <M SSV, Furthermore, this is much smaller than the MSSV produced by a simple spin valve (SSV) layer structure with similar magnetoresistive properties. This layer structure can be called a (leveraged) antiparalelly coupled pinned layer spin valve.

[0041] By using different material compositions that can differ in the chemical elements and / or element ratios, the composition of different magnetic moments in the fixed ferromagnetic layers of the reference layer stack is altered. Thus, the first fixed ferromagnetic material composition can be a CoFe alloy, where the mass percentage or atomic percentage of Fe is particularly between 5% and 15%, preferably 10%. The second fixed ferromagnetic material composition can be a CoFeB alloy, where, within the corresponding tolerance range, the mass percentage or atomic percentage of Co and Fe is 40%, and the proportion of B is 20%. Here, the tolerance range includes a deviation of the corresponding proportion from the value mentioned for that proportion not exceeding 5 percentage points, preferably not exceeding 2.5 percentage points.

[0042] In addition, the first fixed ferromagnetic layer may have a first layer thickness. l1, and the second fixed ferromagnetic layer may have a second layer thickness. l2, where the quotient of the thickness of the first and second layers is... l1 / l2 is between 1.2 and 2.5.

[0043] Compared to the layered structure mentioned at the beginning, and especially compared to the APP structure, the pinning magnetic field strength required in this implementation is reduced by approximately 10 times. Therefore, this improved LAPP scheme for layered structures represents an optimization in terms of the feasibility of the pinning process, thermal and magnetic stability, and the magnitude of the TMR effect.

[0044] The antiferromagnetic layer can be made of FeMn, IrMn, PtMn, or NiMn, and can have a thickness between 5 nm and 30 nm.

[0045] According to an advantageous embodiment, the coupling layer comprises, in particular, only Ru, and has a thickness between 0.3 nm and 1.5 nm, preferably between 0.35 nm and 0.85 nm, and most preferably 0.5 nm. The coupling layer achieves an antiparallel orientation of the second fixed ferromagnetic layer relative to the first fixed ferromagnetic layer. The coupling layer may, for example, be composed of a nonmagnetic metallic material, such as Ru, and may have a thickness between 0.3 nm and 1.5 nm.

[0046] In an advantageous improvement, the plurality of TMR layer structures of a bridge resistor can be arranged as rows, particularly curved rows, on the substrate. Furthermore, it is preferable that the rows of bridge resistors are arranged adjacently on the substrate, particularly in a serpentine and nested manner, especially in an interdigitated interlocking arrangement, in which rows of different bridge resistors are arranged alternately side-by-side. This allows for a compact chip design while ensuring that the magnetoresistive characteristics of adjacent bridge resistor components are substantially the same.

[0047] In an advantageous improvement, the center-to-center spacing Δd between adjacent TMR layer structures of different bridge resistors is 50 µm or less, preferably 20 µm or less, and especially 12 µm or less. Advantageously, this allows two identically constructed and adjacent TMR elements to be disposed on a single substrate, and the magnetization directions of the corresponding first fixed ferromagnetic layer and, if necessary, a second fixed ferromagnetic layer can be different from each other, particularly oriented oppositely. In this case, the adjacent TMR elements comprise the same layer group and are fabricated in the same deposition process, particularly simultaneously. Here, the center-to-center distance between adjacent TMR elements... d can preferably be 50 µm or smaller, particularly 20 µm or smaller. Here, by at least temporarily placing a ferromagnetic, preferably soft magnetic, structured element between the two TMR elements, the pretreatment magnetic field can be coupled into the structured element, preferably perpendicular to the substrate surface. The stray field of the structured element acts as an effective pinning magnetic field along the edge of the structured element to orient the magnetic orientation of the first fixed ferromagnetic layer, the stray field comprising field components oriented parallel to the substrate surface and perpendicular to the side surface of the structured element. For this purpose, a layer structure on the substrate or a small center-to-center distance between the TMR elements can be selected. d, and during this process, structured elements are constructed or temporarily introduced on the substrate, for example, in the form of punches. The pretreatment magnetic field can act across the entire surface of the substrate, where, at the location of the structured element, corresponding to the edge orientation of the pretreatment magnetic field, pinning can be achieved by a locally acting pinning magnetic field derived from the pretreatment magnetic field in different directions parallel to the substrate surface. Unlike conventional laser pinning methods, where an in-plane pinning magnetic field is coupled parallel to the substrate surface—thus the pretreatment magnetic field equals the pinning magnetic field—and is briefly heated by laser to exceed the blocking temperature, this improved approach allows for pinning of almost all layer structures on the substrate in different directions over arbitrarily long time periods at low magnetic field strength. In practice, this means that all TMR elements of all sensors on a chip substrate can be pinned in a single step.

[0048] Typically, the pinning direction of the first fixed ferromagnetic layer is located in the principal axis direction. In an advantageous improvement, at least three, especially four or more, TMR layer structures of adjacent bridge resistors can be arranged adjacent to each other in a row. In this case, the first fixed magnetization directions of these TMR layer structures can be different from each other; in particular, the first fixed magnetization directions of the paired opposing layer structures of adjacent bridge resistors can be oriented substantially 180° opposite to each other in the principal axis direction SA, in order to provide multiple pinning and to achieve harmonic filtering with respect to the measurement of the magnetic field along the principal axis direction. Preferably, the series circuit of multiple TMR layer structures of a bridge resistor can include multiple sets of TMR layer structures, the first fixed magnetization directions of which can be symmetrically tilted about the principal axis direction SA, preferably tilted 90°, 45°, 36°, 30° or 15° relative to each other.

[0049] In an advantageous improvement, in each layer structure, at least the first fixed ferromagnetic layer can be composed of a first ferromagnetic material, preferably CoFe / CoFeB. Furthermore, prior to the annealing process, the free ferromagnetic layer can be composed of a boron-containing second ferromagnetic material, preferably a boron-containing cobalt-iron compound, particularly CoFeB. In this case, the thickness of the free ferromagnetic layer can be less than the thickness of the first fixed ferromagnetic layer, and can be at most 1.5 nm or less. The fixed ferromagnetic layer, i.e., the reference layer or antiferromagnet, can have a greater layer thickness to obtain more external magnetic field signals, and thereby be magnetized in the layer plane and not perpendicular to the layer plane according to the orientation of the antiferromagnet.

[0050] In an advantageous improvement, a structure of at least a single layer of a third material composition can be formed as an annealing process layer on the side of the free ferromagnetic layer facing away from the nonmagnetic intermediate layer, directly adjacent to the free ferromagnetic layer. The third material composition preferably comprises Ta, Hf, W, Mo, TaN, or TaO. The third material composition of the annealing process layer is adapted to absorb boron from the boron-containing second ferromagnetic material composition of the free ferromagnetic layer during annealing without itself diffusing into the free ferromagnetic layer. The structure preferably has a layer thickness in the range of 5 to 10 nm. The third material composition acts like a sponge to absorb boron from the free ferromagnetic layer during the crystallization process from amorphous CoFeB to crystalline CoFe, without itself diffusing into the free ferromagnetic layer. Therefore, the proposed structure for forming a free ferromagnetic layer containing CoFeB and an annealed process layer containing a boron-absorbing material is configured on a fixed ferromagnetic layer and a reference layer to form the following material and layer structure: a non-magnetic intermediate layer (MgO or AlOx) + a free ferromagnetic layer (CoFeB) + an annealed process layer containing a material that can absorb boron from CoFeB without itself "migrating" into CoFeB. The material can be Ta, Hf, W, Mo, TaN, or TaO.

[0051] In a favorable improvement, the nonmagnetic intermediate layer can be made of a nonferromagnetic metal oxide, particularly MgO or AlO. x It is composed primarily of Al₂O₃ and has a layer thickness between 1 nm and 3 nm, preferably between 1.8 nm and 2.2 nm, and especially 2 nm. Alternatively or additionally, the non-magnetic intermediate layer may have a thickness of 200 Ωμm. 2 Up to 200 kΩμm 2 Especially 400Ωμm 2 Up to 3 kΩμm 2 The surface resistance Ra is the area of ​​the non-magnetic interlayer. The resistance R of the non-magnetic interlayer is derived from R = Ra / A, where Ra is the surface resistance and A is the area of ​​the interlayer, and the unit of resistance is [Ω] = [Ω µm2] / [µm2]. Therefore, Ra = R is applicable to surface resistance. A, therefore, [Ohmµm2] = [Ohm] [µm²]. Since measuring layer thickness can be difficult, a given value of sheet resistivity Ra corresponds to the corresponding layer thickness. For non-magnetic interlayers, the sheet resistivity is advantageously between 200-200000 Ω µm. 2 Especially 400-3000 Ω µm 2 Within a certain range. The surface resistance Ra describes the resistance with respect to the thickness of the nonmagnetic intermediate layer and the resistivity value as a material constant.

[0052] In an advantageous improvement, the TMR layer structure is disposed on a substrate such that each TMR layer structure can be configured to have a lower base electrode and an upper termination electrode, the lower base electrode preferably being configured as a seed layer (seed crystal layer). Here, in the at least one first fixed magnetization ferromagnetic layer, the first fixed magnetization direction can be oriented along the pinning direction, and in the free ferromagnetic layer, a second magnetization direction oriented perpendicular to the first fixed magnetization direction can be freely adjusted in the absence of a magnetic field. Thus, the layer structure is advantageously disposed on the substrate, at which point a so-called seed layer can be applied between the substrate and the antiferromagnetic layer, the seed layer promoting the growth of the antiferromagnetic layer, and the seed layer serving as a base electrode. In principle, the layer structure between the seed layer and the covering or termination electrode layer can be disposed on the substrate in the reverse order of the order described herein.

[0053] In an advantageous embodiment, the temperature-slope characteristic curve of the output signal S of the bridge resistor assembly exhibits a substantially constant behavior with respect to temperature T, at least within a temperature range of -40°C to 120°C, and preferably within a range of less than or equal to ±0.2% / K, particularly ±0.1% / K. The temperature-slope characteristic curve characterizes the change in signal sensitivity S (%) with ambient temperature (Kelvin K). Thus, the behavior of the characteristic curve describes the effect of the ambient temperature on the sensor signal behavior. This change in behavior, i.e., the gradient of the temperature-slope characteristic curve, is given as the TC_Slope characteristic value. The suggestion in this embodiment is that the change in behavior is constant, i.e., the signal behavior is linear with respect to temperature changes, i.e., the TC_Slope characteristic value remains constant with temperature, and the temperature-slope characteristic curve forms a straight line over temperature. Furthermore, a very small gradient of + / -0.2% / K, particularly + / -0.1% / K, is proposed, meaning that the sensitivity change with temperature is very small, thus making the bridge resistor assembly extremely robust to temperature fluctuations. This can be achieved by appropriately selecting manufacturing parameters, such as the duration and magnitude of the manufacturing process temperature and the selection of suitable materials.

[0054] In a parallel aspect, a magnetically sensitive bridge circuit is proposed, particularly for current sensors or angle sensors, and preferably for vector measurement of weak magnetic fields up to 30 mT. The bridge circuit comprises: a substrate; an arrangement system of at least two or more bridge resistors adjacent to each other on the substrate according to any of the preceding embodiments; and at least one ferromagnetic, preferably soft-magnetic, structured element that can be at least temporarily introduced and is adjacent to or partially overlapped with the corresponding TMR layer structure, preferably overlapping between two or more adjacent TMR layer structures. The structured element can be constructed and configured to influence a pre-processed magnetic field Hz entering the structured element, such that, at least in the first fixed ferromagnetic layer of the adjacent TMR layer structure, a magnetic field component oriented differently from the stray magnetic field of the structured element acts as a pinning field M0, the magnetic field component extending parallel to the layer plane of the TMR layer structure. The pretreatment magnetic field Hz can be coupled into the structured element preferably perpendicular to the surface of the substrate, and the resulting pinning field M0 can pin the first fixed magnetization direction of the at least one first fixed ferromagnetic layer during the annealing process, and can simultaneously form a PMA layer structure of a free ferromagnetic layer of a TMR layer structure.

[0055] For example, ferromagnetic, preferably soft magnetic, structured elements made of photolithographically structured nickel-iron alloy are configured such that a pre-processing magnetic field is simultaneously and perpendicularly coupled into the one or more structured elements, and a magnetic field component parallel to the surface of the corresponding layer structure is generated at the location of the layer structure, the magnetic field component at least partially penetrating the first and second ferromagnetic layers. Thus, adjacent layer structures can be penetrated by pinning magnetic fields of different orientations, preferably opposite orientations. Therefore, the pre-processing magnetic field can be a uniform magnetic field perpendicular to the surface of the layer structure, and due to the magnetic permeability and geometry of the structured elements, the non-uniform stray field of the pre-processing magnetic field also emanates parallel to the surface of the layer structure at the edges, pinning adjacent layer structures. Thus, arbitrary pinning directions can be set in the corresponding layer structures, and a single structured element can simultaneously pin multiple layer structures in different directions. The different pinning directions depend essentially on the contour shape of the structured element relative to the substrate surface that defines the structured element.

[0056] The pinning method is carried out at a pinning temperature above the blocking temperature between the antiferromagnetic layer and the first fixed ferromagnetic layer for a predetermined pinning time. This duration and process temperature are advantageously used simultaneously for the annealing process in the free ferromagnetic layer to crystallize the amorphous CoFeB into CoFe, thereby simultaneously providing PMA orientation for the free ferromagnetic layer.

[0057] It has been shown that ferromagnetic, preferably soft magnetic, structured elements are particularly suitable for pinning layer structures on a substrate. This can be attributed to the fact that, in order to pin the layer structures of this disclosure, only a low-intensity pretreatment magnetic field with a strength of less than 500 mT, preferably less than 130 mT, needs to be provided in the plane of the substrate, and the resulting pinning magnetic field is even smaller, typically less than 80% of the strength of the pretreatment magnetic field, and in most cases less than 50%. In particular, multiple layer structures according to this disclosure can be arranged on a single magnetic field sensor, these layer structures being magnetized in different spatial directions, and particularly forming a Wheatstone bridge.

[0058] In another parallel aspect, a method for manufacturing a bridge resistor assembly according to any of the foregoing embodiments is proposed, the method comprising the following steps: - Apply adjacent TMR layer structures to the substrate in the order described or in the reverse order between the seed layer and the capping layer; - Apply at least one preferably temporarily disposed ferromagnetic structuring element between adjacent TMR layer structures; - The TMR layer structure is heated to a temperature of at least 260°C to a maximum of 350°C above the blocking temperature in order to initiate the annealing process. At this time, the exchange coupling between the antiferromagnetic layer and the first fixed ferromagnetic layer is released, and the PMA layer structure begins to form in the free ferromagnetic layer. - During the annealing process, a pretreatment magnetic field with a flux density of less than 500 mT, particularly perpendicular to the surface of the substrate, is coupled into the heated TMR layer structure to simultaneously establish a pinning field M0 for a predetermined duration of at least 1 h and at most 12 h. This pinning field has different first fixed magnetization directions for the at least one first fixed ferromagnetic layer of adjacent TMR layer structures, during which the temperature of the TMR layer structure is above the blocking temperature. - After a predetermined time has elapsed since the end of the annealing process, the TMR layer structure is cooled to a temperature below the blocking temperature in the presence of a pretreatment magnetic field Hz. Thus, a free magnetization direction is formed simultaneously in the free ferromagnetic layer, which is the PMA layer structure, with a first fixed magnetization direction different from that in the adjacent TMR layer structure.

[0059] Optionally and preferably, the temporarily introduced ferromagnetic, preferably soft magnetic, structured elements can be removed again immediately after the annealing process.

[0060] In the first step, at least one, particularly multiple, magnetoresistive layer structures are applied to the chip substrate, the magnetoresistive layer structures having layer structures corresponding to one or more of the aspects described above. To orient the pinning direction in the first fixed ferromagnetic layer or the first and second fixed ferromagnetic layers, a temperature above the blocking temperature is applied, causing the exchange interaction between the first fixed ferromagnetic layer and the antiferromagnetic layer to be released. The fixed layer is now no longer pinned by the adjacent antiferromagnetic layer and behaves similarly to a free ferromagnetic layer. Next, an external magnetic field, also known as a pretreatment magnetic field, is coupled in, where the field lines guiding the magnetic field are guided through ferromagnetic, preferably soft magnetic, structured elements, i.e., in a stray field with magnetic field lines oriented parallel to the substrate plane, so that the field lines enter the layer structure at appropriate locations as pinning magnetic fields parallel to the layer plane, and here achieve adjustable magnetization of the first ferromagnetic layer.

[0061] Simultaneously with the pinning process, the annealing process in the free layer proceeds as follows: During annealing, for example, tantalum composed of a third material can absorb boron from the amorphous CoFeB in the free layer. The remaining CoFe then possesses a cubic bcc structure similar to MgO, which in turn leads to high interfacial anisotropy. The high PMA originates from the hybridization of the 3d orbitals of Co and Fe with the p orbitals of oxygen. Charge transfer occurs to the oxygen orbitals, while the out-of-plane 3d orbitals have fewer electrons compared to the in-plane 3d orbitals. This ultimately leads to an increased out-of-plane orbital moment, and ultimately to PMA. In CoFe(B), two effects now coexist. On the one hand, there is the out-of-plane PMA formed at the interface; on the other hand, there is the in-plane bulk anisotropy. Which effect dominates depends on the composition of CoFeB, the annealing or pinning temperature, and the layer thickness of CoFeB.

[0062] The annealing and pinning conditions in terms of time and temperature must be selected such that: - Formation of PMA; - In the case of multiple pinning methods, a strong and stable coupling is established between the antiferromagnetic layer and the first ferromagnetic layer.

[0063] The exchange coupling between the antiferromagnetic layer and the first ferromagnetic layer is established in the magnetic field only when cooled below the blocking temperature. The first ferromagnetic layer is oriented according to the external magnetic field. When cooled below the blocking temperature of the antiferromagnetic layer, the spin of the antiferromagnetic layer at the interface between the antiferromagnetic layer and the first fixed ferromagnetic layer follows the spin of the first fixed ferromagnetic layer and remains in this orientation even below this temperature.

[0064] Now, when the external magnetic field disappears, as long as the temperature is below the blocking temperature, the pinning magnetization of the first fixed ferromagnetic layer remains fixed in its orientation by the antiferromagnetic layer. Above this, the antiferromagnetic layer loses its antiferromagnetic properties. Here, the annealing process of the free layer must be designed so that boron is absorbed in the free ferromagnetic layer through a diffusion process, and the conversion of amorphous CoFeB to crystalline CoFeB is altered, so that perpendicular magnetization is formed simultaneously with the pinning process. After the manufacturing process is completed, the ferromagnetic, preferably soft magnetic, or individual structural elements introduced to individually adjust the pinning direction in the fixed ferromagnetic layer are usually removed again.

[0065] In an advantageous improvement to the manufacturing method, the arrangement system of the TMR layer structure can be heated to a temperature of at least 270°C to 290°C, particularly 280°C, in order to pin the fixed ferromagnetic layer and to anneal the free layer. Preferably, this temperature can depend on the thickness of the free ferromagnetic layer. This is because there is a correlation between the annealing temperature and the thickness of the free layer, which is crucial for magnetic orientation, through the dead layer formed by diffusion and the crystallinity of CoFeB.

[0066] In an advantageous improvement to the manufacturing method, the magnetic induction intensity of the coupled pretreatment magnetic field Hz is less than 200 mT, and particularly less than 100 mT. Therefore, TMR elements, especially those based on the LAPP-leveraged antiparalelly coupled pinned layer spin valve structure, can be easily and cost-effectively manufactured.

[0067] In an advantageous improvement to the manufacturing method, the duration for pinning the fixed ferromagnetic layer and annealing the free layer can be between 3 hours and 7 hours, particularly 5 hours. By selecting the coupling time at high temperature, ordered L10 layer orientation of the antiferromagnetic layer can be achieved, thereby significantly improving the antiferromagnetic properties and optimizing the crystallization process for achieving PMA orientation in the free layer.

[0068] The annealing time and annealing temperature used for PMA orientation to form the free layer are also the pinning duration and pinning temperature, and significantly affect the temperature sensitivity of the bridge resistor assembly. It has been demonstrated that the temperature-slope characteristic curve can be specifically adjusted by changing the annealing temperature or annealing time.

[0069] In another parallel aspect, a method for manufacturing the aforementioned magnetically sensitive bridge circuit is proposed, the method comprising the following steps: - A bridge resistor assembly is manufactured according to the aforementioned and related manufacturing methods; wherein - At least temporarily applying the at least one ferromagnetic, preferably soft magnetic, structured element, wherein - During the annealing process, the pretreatment magnetic field Hz is coupled as a pinning field M0 into the TMR layer structure with different magnetization directions through the structured elements. Simultaneously, a PMA layer structure is formed in the free ferromagnetic layer during the annealing process, and preferably thereafter... - After the annealing process is complete, the structured element is removed again.

[0070] The method according to this disclosure is used to manufacture a magnetically sensitive bridge circuit according to this disclosure, the magnetically sensitive bridge circuit including at least one ferromagnetic, preferably soft magnetic, structured element according to the foregoing aspects, the method including the foregoing method for manufacturing a layer structure along with advantageous design of the method for simultaneously pinning a fixed ferromagnetic layer and annealing a free ferromagnetic layer to establish a PMA orientation, and including at least temporarily applying the at least one structured element.

[0071] According to this disclosure, a pretreatment magnetic field is coupled into the layer structure as a pinning magnetic field via the structured element. During the pinning process, the material composition of the free layer crystallizes through an annealing process. Preferably, the structured element can be removed again after pinning is completed, so that the structured element can be temporarily applied to the substrate, for example by conventional photolithography and electroplating methods, and then removed again by means of etching or material removal methods. It is also conceivable to temporarily lower the structured element in the form of a punch above the substrate, thereby coupling the pretreatment magnetic field. Alternatively, the ferromagnetic structured element can also be retained at least partially as a flux guiding element for an external magnetic field.

[0072] In an advantageous improvement to the method for manufacturing the aforementioned magnetically sensitive bridge circuit, an arrangement of at least two adjacent and spaced-apart bridge resistors can be applied to the substrate, and structured elements can be applied to the substrate at least temporarily between adjacent rows of the TMR layer structure forming the bridge resistors. During the combined pinning and annealing process, a pretreatment magnetic field Hz can be coupled into the structured elements perpendicular to the substrate surface. This allows stray magnetic fields generated by the structured elements to provide different orientations of the adjacent TMR layer structure pinning fields M0, which are substantially parallel to the substrate surface. The orientation of these pinning fields depends on the side geometry of the structured elements, such that the orientations of the pinning fields M0 of adjacent TMR layer structures can be different from each other, particularly substantially opposite, while a PMA layer structure can be formed in the free layer. The orientation of the pinning-effective magnetic field component from the pretreatment magnetic field, parallel to the substrate surface, depends on the edge geometry of the structured elements, such that the orientations of the pinning magnetic fields of adjacent layer structures are preferably different from each other, particularly opposite. With this improved manufacturing method, even when the reference layer of the TMR element contains two antiparallel coupled fixed ferromagnets, the TMR element can be pinned in different preferred directions in a spatially close arrangement using a weaker pre-treated magnetic field of less than 500mT, preferably less than 200mT, and especially less than 100mT.

[0073] In other words, by combining these methods, particularly the possibility of long-term pinning and simultaneous annealing, with the combination of the layer structure in a specific order (material selection) of closely adjacent arrangement structures and materials, it is possible to provide particularly thermally stable antiferromagnetic materials in the optimized L10 phase, such as IrMn, PtMn, and NiMn, in the sensor with additionally thermally stable antiferromagnetically coupled first and second fixed ferromagnetic layers and free ferromagnetic layers with PMA orientation. Furthermore, different TMR elements can be additionally arranged in a narrow space. These TMR elements have the same characteristics and are identically manufactured, except for the pinning direction of the reference layer. The pinning directions can be arbitrarily different in direction, and preferably oriented in opposite directions.

[0074] Other advantageous designs of the layer structure, the magnetoresistive bridge circuit, and the manufacturing method are derived from the specification, drawings, and dependent claims. Attached Figure Description

[0075] Other advantages are apparent from the accompanying drawings, in which embodiments of this disclosure are illustrated. The drawings, description, and claims contain a large number of combinations of features. Those skilled in the art will be able to readily consider these features individually and combine them into other meaningful combinations.

[0076] Figures 1a-1c The structure consisting of adjacent bridge resistor assemblies according to two embodiments of the present disclosure is schematically illustrated with detailed diagrams; Figure 2 This schematically illustrates one embodiment of a bridge resistor assembly with respect to an external magnetic field H. ext Signal behavior with varying intensity; Figure 3 This schematically illustrates one embodiment of a bridge resistor assembly in an angle sensor with respect to an external magnetic field H. ext Another signal behavior of rotational behavior; Figure 4 The schematic diagram illustrates a pinning assembly for securing a first fixed ferromagnetic layer in one embodiment of pinning two adjacent bridge resistor assemblies. Figure 5a , 5b A graph showing the temperature dependence of sensor sensitivity at different temperature levels during annealing and pinning processes; Figure 6a , 6b Figures 6c show a circuit diagram and chip substrate configuration of a bridge resistor assembly in the prior art and an embodiment of the present disclosure. Detailed Implementation

[0077] In the accompanying drawings, elements of the same type are numbered using the same reference numerals. The drawings are for illustrative purposes only and should not be construed as limiting.

[0078] Figure 1a and Figure 1b Two alternative embodiments of the adjacent arrangement of the TMR layer structure 22 of the bridge resistor assembly 20 are shown, wherein Figure 1a The diagram shows an SSV layer structure 70 with a fixed ferromagnetic layer 26, while Figure 1b The LAPP layer structure 72 shown is a TMR layer structure 22 with two fixed ferromagnetic layers 26 and 27, the thickness of which is... l1、 l2 is different, and the thickness affects the magnetic moment of the fixed ferromagnetic layer. The series circuits of multiple TMR layer structures 22 form a bridge resistor, here, Figure 1a , 1b The TMR layer structure 22 of adjacent bridge resistors in the bridge resistor assembly 20 is schematically shown. For clarity, in Figure 1a , 1b The annealing process layer 33, which is beneficial to the annealing process, is not shown in the diagram. Figure 1c Detailed explanation follows.

[0079] The different layers of the TMR layer structure 22 are applied by coating methods known and commonly used in semiconductor technology, such as chemical and physical vapor deposition methods or commonly used sputtering methods.

[0080] One or more TMR layer structures 22 are disposed on a semiconductor substrate or chip substrate 12. First, a seed layer 40 is applied on the chip substrate 12, the seed layer 40 being selected such that the subsequently applied antiferromagnetic layer 24 grows with optimal characteristics. The seed layer 40 is characterized by sufficiently high conductivity and as low a surface roughness as possible, so that the seed layer 40 forms a first electrical connection point as a base electrode 38.

[0081] An antiferromagnetic layer 24 is applied to the seed layer 40. This antiferromagnetic layer is composed, for example, of FeMn, NiMn, IrMn, or PtMn, with a typical layer thickness between 5 nm and 30 nm. Next, a first ferromagnetic layer 26 is applied to the antiferromagnetic layer 24. This first ferromagnetic layer is composed of a CoFe alloy, typically Co90Fe10 (given by mass percentage) or CoFeB, and is applied with a thickness of 1 nm to 3 nm, typically 2.3 nm. This is performed by a pinning method, imparting a fixed magnetization 28 in one direction within the layer plane of the reference layer stack. According to... Figure 1a In the case of the SSV layer structure, the antiferromagnetic layer 24 and the first ferromagnetic layer 26 form a reference layer stack.

[0082] According to Figure 1bIn the LAPP layer structure 72, a coupling layer 25 is connected after the first ferromagnetic layer 26. This coupling layer is made of Ru with a thickness between 0.35 nm and 1.0 nm, typically 0.5 nm. The coupling layer 25 achieves antiparallel magnetic orientation of the second ferromagnetic layer 27 relative to the first ferromagnetic layer 26 via RKKY coupling. The second ferromagnetic layer 27 is deposited onto the coupling layer 25. This second ferromagnetic layer is made of a CoFeB alloy, typically Co40Fe40B20. Here, the thickness of the second ferromagnetic layer 27 is chosen such that the magnetic moments of the deposited, unpinned ferromagnetic layers 26 and 27 exhibit a desired ratio. This ratio, more precisely, is the quotient M1 / M2 of the magnetic moment M1 of the first ferromagnetic layer 26 and the magnetic moment M2 of the second ferromagnetic layer 27, which advantageously has a value between 1.3 and 2.3, preferably between 1.6 and 2.0.

[0083] Regarding the material composition of the ferromagnetic layers 26 and 27 mentioned above, this corresponds to the physical thickness of the first ferromagnetic layer 26. 1 and the physical thickness of the second ferromagnetic layer 27 2 is in the range of 1.36 to 1.94, typically a ratio or quotient of 1.6. l1 / l2. The pinning method involves imparting a fixed magnetization 28 to the first fixed ferromagnetic layer 26 in one direction within the layer plane of the stacked reference layers, and imparting an antiparallel magnetization 29 to the second fixed ferromagnetic layer 27, scaled proportionally to the magnetic moment. According to... Figure 1b In the case of the LAPP layer structure 72, the antiferromagnetic layer 24, the first ferromagnetic layer 26, the coupling layer 25, and the second ferromagnetic layer 27 together form a reference layer stack. To achieve different magnetic moments, the two ferromagnetic layers 26 and 27 can have different material compositions and / or different layer thicknesses. For this purpose, a layer with a thickness of [missing information] is shown. The first ferromagnetic layer 26 of l1 and having a thickness The second ferromagnetic layer 27 of l2, where the reduced thickness indicates a reduced magnetic moment.

[0084] Furthermore, a non-magnetic intermediate layer 34 is applied on the reference layer stack, or above the second ferromagnetic layer 27. This intermediate layer is preferably a non-conductive layer made of MgO, but can also be made of AlOx, particularly Al2O3. The thickness of this intermediate layer is chosen such that the magnetoelectric tunneling effect, typically between 20% and 200%, and the tunneling resistance of the TMR layer structure, typically between 100 Ω and 30 kΩ, are optimized for the relevant application. Here, the layer thickness can be between 1 nm and 3 nm, preferably between 1.8 nm and 2.2 nm, particularly 2 nm. Alternatively or additionally, the non-magnetic intermediate layer can have a thickness of 200 μm. 2 Up to 200kΩμm2 Especially 400Ωμm 2 Up to 3kΩμm 2 The surface resistance Ra within the range.

[0085] Finally, a free ferromagnetic layer 30 is applied to the non-magnetic intermediate layer 34. This free ferromagnetic layer comprises a boron-cobalt-iron compound, particularly CoFeB material. Additionally, one or more other elements may be alloyed to maximize the TMR effect. The thickness of the free ferromagnetic layer should be less than that of the first fixed ferromagnetic layer, and at most 1.5 nm or less. Within the framework of the pinning method for imparting fixed magnetizations 28 and 29 to the first and possibly second ferromagnetic layers 26 and 27, a crystallization process is performed in the free layer via annealing, thereby resulting in a PMA orientation with a free magnetization direction 32 in a field-free state. Here, the free magnetization direction 32 is perpendicular to the X / Y layer plane of the TMR layer structure 22 and oriented along the Z direction. The annealing process is performed simultaneously with the pinning process.

[0086] An annealing process layer 33 is formed on the free ferromagnetic layer 30 by providing another structure of at least a single layer of a third material composition. The third material composition preferably includes Ta, Hf, W, Mo, TaN, or TaO. See [reference needed]. Figure 1c China as Figure 1a A detailed diagram of a single TMR layer structure 22, which is part of the SSV layer structure 70 arrangement system. For clarity, in Figure 1a , 1b The annealed process layer 33 is not shown, and the thickness of the free ferromagnetic layer 30 is shown larger than it actually is to show the PMA orientation of the free magnetization direction 32. The third material composition of the annealed process layer 33 is designed to draw boron from the boron-containing second ferromagnetic material composition of the free ferromagnetic layer during annealing, without itself diffusing into the free ferromagnetic layer. The structure of the annealed process layer 33 can have a layer thickness in the range of 5 to 10 nm. The annealed process layer 33 acts like a sponge to convert amorphous CoFeB into crystalline CoFe within the scope of the crystallization process initiated by the annealing process, by absorbing boron from the free ferromagnetic layer.

[0087] In addition, one or more non-magnetic layers, such as metal electrode layer 42 or cover layer 44, are provided on layer structure 22 to enable electrical contact with layer structure 22 and to isolate the layer structure from environmental influences or components located on or adjacent to it.

[0088] Layers 24 to 44 can also be applied to the chip substrate 12 in reverse order between the cover layer 44 and the seed layer 40.

[0089] also, Figure 1a and1b The diagram schematically illustrates an arrangement of two adjacent bridge resistors 14 of a bridge resistor assembly 20, the arrangement having a distance between their central axes. d. A TMR layer structure 22 in the size range of 5µm to 50µm. For application in magnetic field sensors, the individual magnetoresistive resistors (magnetoresistors) 14 of a measurement bridge need to have different pinning orientations; ideally, these resistors are identically constructed and spatially close together to homogenize resistive behavior. This is in Figure 1a , 1b This is implemented as follows: the center distance of the reference layer stack The diameter d is between 5µm and 50µm, and the pinning directions 28 and 29 of adjacent reference layer stacks are oriented in opposite directions. Thus, under an external magnetic field, the resistive behavior of adjacent TMR layer structures 22 of the bridge resistor assembly 20 is opposite.

[0090] To enable the two pinning directions 28 / 29 to be oriented differently, a ferromagnetic structured element 50 can be advantageously temporarily introduced between the two TMR elements 22, and the structured element is passed through by a pre-processed magnetic field Hz in the Z direction. At this time, the structured element 50 forms a stray magnetic field, which acts as a pinning field M0 to pin the first fixed ferromagnetic layer 26 and possibly the second fixed ferromagnetic layer 27. This is schematically illustrated in... Figure 4 As shown in the image.

[0091] Within the fabrication of the bridge resistor assembly 20, the TMR layer structure 22 undergoes a pinning process for the fixed layers 26 and 27 and an annealing process for the free layer 30. For this purpose, adjacent TMR layer structures 22 are heated to a temperature above the blocking temperature of the TMR layer structure 22, preferably above 260°C, typically 280°C. Then, a pretreatment magnetic field Hz with a small magnetic field strength of no more than 500 mT, preferably no more than 200 mT, particularly less than 130 mT, and especially less than 100 mT is applied to the layer structures 70 and 72. At this point, the field lines of the pinning magnetic field M0, derived therefrom and scattered by the structured elements, extend parallel to the X / Y layer surfaces of the TMR layer structure 22. Simultaneously and in parallel, heating the bridge resistor assembly 22 above the blocking temperature triggers an annealing process in the free ferromagnetic layer 30 to set the PMA orientation of the free magnetic field orientation 32.

[0092] The beneficial effects of PMA orientation in free ferromagnetic layer 30 are... Figure 2 As shown in the figure. Even in the weak field region with a maximum of 30 mT, the sensor signal is related to the external magnetic field H to be measured. ext It changes almost perfectly linearly, thus eliminating the need for additional compensation processes.

[0093] also, Figure 3The external magnetic field H to be measured is shown. ext The signal curves as they increase or decrease, as seen in current sensors used in converter applications in energy technology, or in rotational angle sensors, such as steering wheel angle sensors in vehicle technology, are first recorded with respect to the external field strength H to be measured. ext The amplitude increased, and then decreased. A linear sensor field strength range was determined to exist within the range of Hmin = -60 mT to Hmax = +60 mT. H. The two signal characteristic curves are almost overlapping within the linear region, where the dashed line represents the external magnetic field H. ext The increase in the dotted line indicates a decrease in the external magnetic field, which is attributed to the PMA characteristics of the free ferromagnetic layer 30. At this point, anisotropic errors can be suppressed to a large extent.

[0094] like Figure 4 As schematically shown, the structured element 50 guides a pre-processing magnetic field Hz along the Z-axis, such that the pre-processing magnetic field is drawn out as a pinning magnetic field M0 at the boundary edges of the structured element 50, substantially parallel to the surface of the chip substrate 12, and passes through the spaced TMR layer structures 22 of the bridge resistor assembly 20 in the layer structure plane along a desired antiparallel direction. Pinning of the fixed ferromagnetic layer 26 of the TMR layer structure 22 is achieved, in particular, by setting the temperature above the blocking temperature of the antiferromagnetic layer of the TMR layer structure 22. Furthermore, it is advantageous here that improved flux guidance through the first fixed ferromagnetic layer 26 and possibly the second fixed ferromagnetic layer 27 can be achieved, for example, by corresponding shaping of the boundary edges of the structured element 50 or by the arrangement of the counter pole surfaces (not shown). Synchronously and in combination with the pinning process, an annealing process is performed in the free ferromagnetic layer 30, at which time, for example, in… Figure 1c As shown, boron is drawn from the free ferromagnetic layer 30 through the annealing process layer 33, thereby causing a phase transition between the amorphous phase and the crystalline phase, the crystalline phase providing the PMA orientation of the free magnetic field direction 32.

[0095] In an advantageous embodiment, the edge of the structured element 50 overlaps with the edge of the TMR layer structure 22, such as Figure 4 As shown in the diagram. Thus, the TMR layer structure 22 is traversed by magnetic fields across its entire width, these magnetic fields also having components parallel to the surface of the chip substrate 12. Finally, the magnetic field lines traversing the chip substrate 12 are redirected toward, for example, a counter-polarity surface (not shown) arranged in a ring around the chip substrate 12, thereby allowing different pinning magnetic field directions 28 / 29 to be set in the fixed ferromagnetic layers 26, 27 depending on the orientation of the edges of the structured element 50.

[0096] Figure 5a , 5bA series of experiments demonstrates the effect of annealing temperature on the dependence of sensor sensitivity S on temperature changes. Here, the LAPP layer structure 72 of the bridge resistor assembly 22 is examined, where the thickness ratio of the two fixed ferromagnetic layers 26 and 27 is [missing information]. l1 / l2=1.6. The quality of PMA orientation produced by the annealing process at different annealing temperatures is determined by... Figure 5b The sensor sensitivity S is represented by a temperature-slope characteristic curve as a function of temperature change. This curve shows the dependence of the sensor sensitivity S, expressed in mV / V / mT, on a temperature change T expressed in °C during the measurement process. Ideally, the TC_Slope eigenvalue, given as % / K and describing the slope or gradient of the temperature-slope characteristic curve, is optimally 0, or at least very small, and extends parallel to the temperature axis. Thus, the sensor sensitivity S is technically independent of temperature, i.e., essentially constant or changing only slightly with temperature, and temperature-induced errors can be easily compensated for or do not occur. The characteristic curve shown is an example; its trend does not always need to be perfectly linear but can have small fluctuations and non-linearity.

[0097] exist Figure 5a The diagram shows three different configurations and process temperatures for pinning and annealing processes, where the PMA orientation is set in the free ferromagnetic layer 30 through the annealing process. Figure 5b The temperature-slope characteristic curve of the sensor sensitivity S versus the measured temperature is shown, where the eigenvalue TC_Slope represents the gradient of the temperature-slope characteristic curve with respect to temperature T, expressed as % / K: - Experiment 1: 5h@280°C -> TC_Slope=0% / K - Experiment 2: 5h@265°C -> TC_Slope=0.2% / K - Experiment 3: 5h@300°C -> TC_Slope=-0.35% / K It has been shown that a lower temperature of 265°C results in a positively increasing temperature-slope characteristic curve, while a higher temperature of 300°C results in a negatively increasing or decreasing temperature-slope characteristic curve. The preferred parameter configuration occurs at an annealing time of 5 hours and an annealing temperature of 280°C, which results in a temperature-independent behavior of the sensor sensitivity S. Other parameters can also be considered, such as longer durations at lower temperatures or shorter durations at higher temperatures.

[0098] at last, Figure 6a , 6b and 6c in Figure 6a The diagram shows a bridge circuit diagram, the chip layout of a bridge circuit 100 for a prior art single-axis magnetic field sensor, and... Figure 6b The diagram shows the chip layout of a bridge circuit 10 according to one embodiment of the present disclosure.

[0099] Figure 6a A circuit diagram of a magnetic bridge circuit 10 for a uniaxial magnetic field sensor is shown. The magnetic bridge circuit 10 includes four magnetic bridge resistors 14. Bridge resistors R1-R4 and R2-R3 define half-bridges of the bridge circuit 10, where sensor signals S+ and S- can be acquired between the center taps of the half-bridges. Each bridge resistor 14 has a magnetic principal axis direction SA, in which the applied external magnetic field H to be measured... ext At this time, the bridge resistor 14 has a maximum or minimum resistance value. The orientation of the vector summation of the principal axis directions SA defines the effective measurement axis of the sensor in the bridge circuit 10. The magnetically sensitive bridge circuit 10 includes two bridge arms, in each arm, two bridge resistors 14 with opposite principal axis directions SA are connected in series, and the bridge resistors 14 arranged side by side in parallel in the bridge arms also have opposite principal axis directions SA. The sensor signal S can be received at the signal taps S+ and S- of the bridge arms.

[0100] Figure 6b and 6c The chip layout of the TMR layer structure, which interconnects to form bridge resistors 14 and bridge circuits, is shown.

[0101] exist Figure 6b The figure shows a prior art bridge resistor assembly 100. For this purpose, bridge resistors 14, namely R1 and R3, oriented along the positive main axis direction SA+, are disposed on a common chip substrate 12, which can be seen in the upper half of the figure. Bridge resistors 14, namely R2 and R4, oriented in the opposite direction of the main axis SA-, are disposed on individual chip substrates 12 in the lower half of the figure, achieved by rotating the chip substrates 180°. On each chip substrate 12, TMR layer structures 22 are interconnected in rows 46 to form bridge resistors 14, and these TMR layer structures can be connected via bonding pads 52. Thus, a bridge resistor assembly 20 with two bridge resistors 14 is disposed on each chip substrate 12. In the prior art, the TMR layer structures 22 of the chip substrate 12 can only be pinned along a common main axis direction SA. Therefore, two chip substrates 12 are required, and these two chip substrates must be connected by bonding wires to form a full bridge 10, as shown. Figure 6a As shown in the figure. This brings a variety of disadvantages, such as increased space requirements, error-prone bonding wire connections, dispersion of the magnetic sensitivity of the TMR layer structure 22, and increased manufacturing costs.

[0102] In contrast, Figure 6cAn embodiment of the uniaxial magnetic field sensor according to this disclosure is shown. The magnetically sensitive bridge circuit 10 is disposed on a single chip substrate 12 by integrating two bridge resistor components 20, and includes bridge resistors 14 pinned in the positive and negative principal axis directions SA, respectively. Here, the rows 46 of the antiparallel oriented TMR layer structure 22 are spaced very close together. The elements with a diameter of d < 50 μm are arranged adjacent to each other, so that no other functional or structural elements can be placed between the TMR layer structures except for ferromagnetic, preferably soft magnetic, structured elements 50 that can be introduced at least temporarily during manufacturing. The connection pads 52 are configured to connect the power supply voltage VCC-GND and the signal taps S+ / S-. In the prior art... Figure 6b The shortcomings of the prior art magnetic bridge circuit 100 shown herein are thus completely overcome. Furthermore, the PMA characteristics of the free layer 30 provide a linear characteristic curve trend, which is suitable for weak field measurements of magnetic fields up to 100 mT and even up to 30 mT, and enables temperature-independent sensor operation.

[0103] By combining the proposed PMA characteristics of the free layer with multiple pinning methods for achieving different pinning directions on a chip substrate, a magnetic bridge resistor component can be provided. This component can be manufactured at a lower cost and with higher energy efficiency, requires less structural space, has a lower error tolerance for temperature fluctuations, achieves a linear characteristic curve, and provides the possibility of effective harmonic filtering due to the freedom to select the pinning direction through the geometry of the structured element. The different pinning directions can be established through time-synchronized and combined annealing and pinning methods.

[0104] List of reference numerals 10 Magnetic Bridge Circuit 12-chip substrate 14 Bridge Resistor 20 magnetic bridge resistor assembly 22TMR layer structure 24 antiferromagnetic layers 25 coupling layers 26 First fixed ferromagnetic layer 27 Second fixed ferromagnetic layer 28 First fixed magnetization direction 29 Second fixed magnetization direction 30 Free Ferroma Layers / PMA Layers 32 Free magnetization directions 33 Annealing process layer 34 Non-magnetic intermediate layer 38 Lower base electrode 40 seed layers 42 Upper connecting electrode 44 Covering Layer 46TMR layer structure The zigzag arrangement of the 48TMR layer structure 50 ferromagnetic, preferably soft magnetic, structured elements 52 bridge resistor assembly connection pads 70TMR-SSV (Simple Spin Valve) Layer Stack 72TMR-APP (Anti-parallel Coupled Pinning Layer) Spin Valve Layer Stack 100 Prior art bridge resistor components M0 nailing field H ext External magnetic field to be measured Hz preprocessing magnetic field SA spindle direction S signal tap Vcc power supply voltage GND reference voltage d Center distance between adjacent TMR layer structures Thickness of the first fixed ferromagnetic layer l1 Thickness of the second fixed ferromagnetic layer l2 Minimum and maximum field strength of Hmin and Hmax linear sensor value curves H-linear sensor field strength range Bridge resistors R1, R2, R3, and R4 R1-R4, R2-R3 half-bridge resistors S sensor signal S+ and S- bridge circuit signal taps

Claims

1. A magnetically sensitive bridge resistor assembly (20) having at least two bridge resistors (14) arranged adjacently on a substrate (12) for magnetic sensitivity along the main axis (SA), each bridge resistor (14) comprising a series circuit of a plurality of TMR layer structures (22, 70, 72), and each TMR layer structure (22, 70, 72) comprising an antiferromagnetic layer (24), at least one first fixed ferromagnetic layer (26), and a free ferromagnetic layer (30), the first fixed ferromagnetic layer having substantially along the main axis The direction (SA) is a first fixed magnetization direction (28) located in the plane of the TMR layer structure (22, 70, 72), with exchange coupling between the antiferromagnetic layer (24) and the first fixed ferromagnetic layer (26), the free ferromagnetic layer having a free magnetization direction (32), and a non-magnetic interlayer (34) disposed between the free ferromagnetic layer (30) and the at least one first fixed ferromagnetic layer (26), such that the resistive behavior of the magnetic bridge resistor assembly (20) depends on the first fixed magnetization direction (28) and the externally measured magnetic field H. ext The angular deviation between the free magnetization directions (32) is characterized in that, In the absence of a magnetic field, the free magnetization direction (32) is perpendicular to the first fixed magnetization direction (28) and perpendicular to the plane orientation of the TMR layer structures (22, 70, 72) to form a perpendicular magnetic anisotropic PMA layer structure. The first fixed magnetization directions (28) of the TMR layer structures (22, 70, 72) adjacently disposed on the substrate (12) of the at least two bridge resistors (14) are different from each other, particularly oriented substantially 180° opposite to each other, at a temperature of at least 260° to a maximum of 350°. At a temperature above the blocking temperature of the first fixed layer (26) at ℃, for a duration from at least 1 h to at most 12 h, and under a predeterminable field strength of a pre-processed magnetic field (Hz) with a magnetic flux density of less than 500 mT, the free ferromagnetic layer (30) is annealed in a free magnetization direction (32) for forming the PMA layer structure, and the first fixed layer (26) is pinned in a first fixed magnetization direction (28) different from each other for forming adjacent bridge resistors (14).

2. The magnetic bridge resistor assembly (20) according to claim 1, characterized in that, A coupling layer (25) and a second fixed ferromagnetic layer (27) are provided between the first fixed ferromagnetic layer (26) and the intermediate layer (34) to form a (lever-type) anti-parallel coupling pinned layer spin valve APP / LAPP layer structure (72).

3. The magnetic bridge resistor assembly (20) according to claim 2, characterized in that, The first fixed ferromagnetic layer (26) has a first magnetic moment, and the second fixed ferromagnetic layer (27) has a second magnetic moment of the APP / LAPP layer structure. Preferably, the quotient of the first magnetic moment and the second magnetic moment of each LAPP structure (74) is not equal to 1, especially between 1.3 and 2.3, preferably 1.

6. In addition, the material composition and / or layer thickness of the first fixed ferromagnetic layer and the second fixed ferromagnetic layer (26, 27) are preferably different.

4. The magnetic bridge resistor assembly (20) according to any one of the preceding claims, characterized in that, The plurality of TMR layer structures (22, 70, 72) of a bridge resistor are arranged as rows (46), especially curved rows (46) on the substrate (12), and rows (48) of the bridge resistor (14) are arranged, especially serpentinely and nested together and adjacent to each other on the substrate (12).

5. The magnetic bridge resistor assembly (20) according to claim 4, characterized in that, The center-to-center spacing (Δd) of adjacent TMR layer structures (22, 70, 72) of different bridge resistors (14) is 50µm or less, preferably 20µm or less, and especially 12µm or less.

6. The magnetic bridge resistor assembly (20) according to any one of the preceding claims, characterized in that, At least three, especially four or more, TMR layer structures (22, 70, 72) of adjacent bridge resistors (14) are arranged adjacent to each other in a row, and the first fixed magnetization direction (28) of these TMR layer structures is different from each other. In particular, the first fixed magnetization direction (28) of the TMR layer structures (22) of adjacent bridge resistors (14) is oriented substantially 180° opposite to each other in the main axis direction (SA). Preferably, the series circuit of multiple TMR layer structures (22, 70, 72) of a bridge resistor (14) includes multiple groups of TMR layer structures (22, 70, 72) whose first fixed magnetization direction (28) is symmetrically tilted about the main axis direction (SA), preferably tilted 90°, 45°, 36°, 30° or 15° relative to each other.

7. The magnetic bridge resistor assembly (20) according to any one of the preceding claims, characterized in that, In each layer structure (22), the at least one first fixed ferromagnetic layer (26) is composed of a first ferromagnetic material, preferably composed of CoFe / CoFeB material, and before the annealing process is performed, the free ferromagnetic layer (30) is composed of a boron-containing second ferromagnetic material, preferably composed of a boron-containing cobalt-iron compound, especially CoFeB. The thickness of the free ferromagnetic layer (30) is less than the thickness of the first fixed ferromagnetic layer (26), and is at most 1.5 nm or less.

8. The magnetic bridge resistor assembly (20) according to claim 7, characterized in that, An annealing process layer (33) is formed on the side of the free ferromagnetic layer (30) facing away from the nonmagnetic intermediate layer (34) with at least a single layer of a third material composition directly adjacent to the free ferromagnetic layer (30). The third material composition preferably includes Ta, Hf, W, Mo, TaN or TaO. The third material composition of the annealing process layer (33) is adapted to draw boron from the boron-containing second ferromagnetic material composition of the free ferromagnetic layer (30) during the annealing process and does not diffuse into the free ferromagnetic layer (30) itself. The structure preferably has a layer thickness in the range of 5 to 10 nm.

9. The magnetic bridge resistor assembly (20) according to any one of the preceding claims, characterized in that, The non-magnetic intermediate layer (34) is made of a non-ferromagnetic metal oxide, particularly MgO or AlO. x Especially composed of Al2O3 and having a layer thickness of 1 nm to 3 nm, preferably 1.8 nm to 2.2 nm, especially 2 nm and / or 200 Ωμm 2 Up to 200 kΩμm 2 Especially 400 Ωμm 2 Up to 3 kΩμm 2 The surface resistance Ra within the range.

10. The magnetic bridge resistor assembly (20) according to any one of the preceding claims, characterized in that, The TMR layer structures (22, 70, 72) are disposed on the substrate (12) such that each TMR layer structure (22, 70, 72) is configured to have a lower base electrode (38) and an upper termination electrode (42), wherein the lower base electrode (38) is preferably configured as a seed layer (40), wherein in the at least one first fixed magnetization ferromagnetic layer (26), the first fixed magnetization direction (28) is oriented along the pinning direction, and in the free ferromagnetic layer (30), the second magnetization direction (32) oriented perpendicular to the first fixed magnetization direction is freely adjustable in the absence of a magnetic field.

11. The magnetic bridge resistor assembly (20) according to any one of the preceding claims, characterized in that, The temperature-slope characteristic curve of the output signal S of the magnetic bridge resistor assembly (20) remains substantially constant with respect to temperature T, at least in the temperature range from -40°C to 120°C, and preferably in the range of less than or equal to ±0.2% / K, especially in the range of ±0.1% / K.

12. A magnetic bridge circuit (10), particularly for use with current sensors or angle sensors, and preferably for vector measurement of weak magnetic fields up to 30 mT, the magnetic bridge circuit comprising: substrate(12); An arrangement system of at least two or more bridge resistors (14) adjacently disposed on a substrate (12) for a magnetically sensitive bridge resistor assembly (20) according to any one of claims 1 to 11; and at least one ferromagnetic, preferably soft magnetic structured element (50) that can be at least temporarily introduced and is disposed adjacent to or partially overlapped with the corresponding TMR layer structures (22, 70, 72), preferably overlapping between two or more adjacent TMR layer structures (22, 70, 72), the structured element (50) being constructed and configured to influence a pre-processing magnetic field (Hz) entering the structured element (50) or each of the structured elements (50), such that at least in adjacent TMR layers In the first fixed ferromagnetic layer (26) of the structure (22, 70, 72), a magnetic field component oriented differently from the scattered magnetic field of the structured element (50) acts as a pinning field (M0). The magnetic field component extends parallel to the layer plane of the TMR layer structure (22, 70, 72). The pretreatment magnetic field (Hz) can preferably be coupled into the structured element (50) perpendicular to the surface of the substrate (12) and pin at least the first fixed magnetization direction (28) of the first fixed ferromagnetic layer (26) during the annealing process by the resulting pinning field (M0), and at the same time forming the PMA layer structure of the free ferromagnetic layer (30) of the TMR layer structure (22, 70, 72).

13. A method for manufacturing a magnetically sensitive bridge resistor assembly (20) according to any one of claims 1 to 11, the method comprising the following steps: - Adjacent TMR layer structures (22, 70, 72) are applied to the substrate (12) between the seed layer (40) and the capping layer (44) in the order described above or in the reverse order; - Apply at least one preferably temporarily disposed ferromagnetic structuring element (50) between adjacent TMR layer structures (22, 70, 72); - The TMR layer structure (22, 70, 72) is heated to a temperature of at least 260°C to a maximum of 350°C above the blocking temperature in order to initiate the annealing process. At this time, the exchange coupling between the antiferromagnetic layer (24) and the first fixed ferromagnetic layer (26) is released, and the PMA layer structure begins to be formed in the free ferromagnetic layer (30). - During the annealing process, a pretreatment magnetic field (Hz) with a magnetic flux density intensity of less than 500 mT, particularly perpendicular to the surface orientation of the substrate (12), is coupled into the heated TMR layer structures (22, 70, 72) to simultaneously establish pinning fields (M0) by ferromagnetic structuring elements (50) for a predetermined duration of at least 1 h and at most 12 h. These pinning fields have different first fixed magnetization directions (28) of at least one first fixed ferromagnetic layer (26) of adjacent TMR layer structures (22, 70, 72) during which the temperature of the TMR layer structures (22, 70, 72) is above the blocking temperature. - After a predetermined time has elapsed since the end of the annealing process, the TMR layer structures (22, 70, 72) are cooled to a temperature below the blocking temperature in the presence of a pretreatment magnetic field (Hz). Thus, a free magnetization direction (32) is formed in the free ferromagnetic layer (30), which is a PMA layer structure, simultaneously with the first fixed magnetization direction (28) in the adjacent TMR layer structures (22, 70, 72).

14. The method according to claim 13, wherein, The arrangement system of TMR layer structures (22, 70, 72) is heated to a temperature of at least 270°C to 290°C, particularly 280°C; preferably, the temperature depends on the thickness of the free ferromagnetic layer (30).

15. The method according to claim 13 or 14, wherein, The magnetic induction intensity of the coupled pre-processed magnetic field (Hz) is less than 200 mT, especially less than 100 mT.

16. The method according to any one of claims 13 to 15, wherein, The annealing process lasts between 3 hours and 7 hours, particularly 5 hours, and the method for manufacturing the magnetic bridge circuit (10) according to claim 12 includes the following steps: - The bridge resistor assembly (20) is manufactured according to the method of any one of claims 13 to 16; wherein - At least temporarily apply the at least one ferromagnetic, preferably soft magnetic, structural element (50), wherein - During the annealing process, the pretreatment magnetic field (Hz) is coupled as a pinning field (M0) into the TMR layer structures (22, 70, 72) with different magnetization directions through the structured element (50). During the annealing process, a PMA layer structure is simultaneously formed in the free ferromagnetic layer (30). Preferably, thereafter... - After the annealing process is complete, the structured element (50) is removed again.

17. The method according to claim 16, wherein, An arrangement of at least two adjacent and spaced-apart bridge resistors (14) is applied on a substrate (12), and a structured element (50) is applied at least temporarily to the substrate (12) between adjacent rows of TMR layer structures (22, 70, 72) forming the bridge resistors (14), and during the annealing process, a pretreatment magnetic field (Hz) is coupled into the structured element (50) perpendicular to the surface of the substrate (12), thereby providing different orientations of the pinning fields (M0) of adjacent TMR layer structures (22, 70, 72) as pinning fields (M0) substantially parallel to the surface of the substrate (12), the orientation of which depends on the side geometry of the structured element (50), such that the orientations of the pinning fields (M0) of adjacent TMR layer structures (22, 70, 72) are different from each other, in particular substantially opposite, while a PMA layer structure is formed in the free layer (30).

Images