Arrangement of adjacent layer structures for a magnetoresistive magnetic field sensor, magnetoresistive magnetic field sensor and method for producing the same

Abstract

The present invention relates to an arrangement of at least two adjacently arranged layer structures for a magnetoresistive magnetic field sensor. Each layer structure comprises at least one antiferromagnetic layer and a first ferromagnetic layer having a first magnetic moment. There is an exchange coupling between the antiferromagnetic layer and the first ferromagnetic layer. In addition, a second ferromagnetic layer having a second magnetic moment is included, wherein the second ferromagnetic layer is antiparallel coupled to the first ferromagnetic layer via a non-magnetic coupling layer arranged between the first and second ferromagnetic layers. It is proposed that the magnetization strengths of the corresponding first ferromagnetic layer and the corresponding second ferromagnetic layer of the adjacently arranged layer structures are different from each other, in particular, have substantially opposite orientations to each other. The present invention also relates to a magnetoresistive magnetic field sensor having such a layer structure arrangement, and a method for producing a layer structure arrangement and a magnetoresistive magnetic field sensor.

Description

Technical Field

[0001] The invention relates to an arrangement of adjacent layer structures for a magnetoresistive magnetic field sensor, comprising at least one antiferromagnetic layer, a first ferromagnetic layer with a first magnetic moment and a second ferromagnetic layer with a second magnetic moment, wherein an exchange coupling exists between the antiferromagnetic layer and the first ferromagnetic layer, and wherein the second ferromagnetic layer is antiparallel coupled to the first ferromagnetic layer via a non-magnetic coupling layer arranged between the first and second ferromagnetic layers.

[0002] The invention also relates to a magnetoresistive magnetic field sensor having such a layer structure arrangement, and to a method for producing a layer structure arrangement and a magnetoresistive magnetic field sensor. Background Art

[0003] Magnetoresistive magnetic field sensors are used for resistance-based magnetic field measurements. By means of a suitable geometric arrangement, further physical quantities such as path, angle or current intensity can be detected. Magnetoresistive magnetic field sensors are based on the magnetoresistive effect. This describes the change in the electrical resistance of a material as a result of the application or modification of an external magnetic field. Magnetic field sensors with a relatively high magnetoresistive effect are based on the giant magnetoresistive effect (GMR effect) or the tunnel magnetoresistive effect (TMR effect), which can be caused by a change in resistance ( =R Max –R Min ) with minimum resistance R Min Alternatively, materials that exhibit the AMR (anisotropic magnetoresistance) effect can be obtained. These effects are also collectively referred to as the xMR effect.

[0004] GMR and TMR magnetic field sensors consist of thin film structures of non-magnetic and magnetic materials, in which the resistance is influenced by magnetic coupling or spin effects through the layers. In GMR and TMR based magnetoresistive layer structures, resistance changes based on external magnetic fields of up to 50% (GMR) or up to 600% (TMR) can be achieved.

[0005] To produce a TMR magnetic field sensor, a layer structure is formed of at least two ferromagnetic layers and an electrically insulating barrier layer, which serves as a tunnel barrier and is also denoted as an intermediate layer, so that a tunnel current can flow between the two ferromagnetic layers. In the case of a TMR magnetic field sensor, the barrier layer consists of, for example, Al2O3 or MgO. In the case of a GMR magnetic field sensor, a thin, non-magnetic but electrically conductive layer of Cu or Ru is usually used. In addition to geometrical parameters such as the surface area, the resistance of the tunnel element 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 On the other hand, if they are magnetized antiparallel to each other, the resistance R Max At maximum value.

[0006] In practice, the magnetization direction of one of the two ferromagnetic layers is often fixed or pinned, so that the magnetization of this layer does not react or reacts only weakly to the external field. This layer is denoted as the reference layer or also the pinned layer. The other layer is configured so that its magnetization can follow the external field in a defined manner. This layer is also called the detection layer or free layer.

[0007] By dividing the reference layer and the detection layer into layers that react differently to the external field, it is possible to achieve a change in resistance when changing the external field and obtain a sensing device. The dependence on the resistance is related to the angle between the magnetization direction of the detection layer (also denoted "free layer") and the magnetization direction of the reference layer (also denoted "pinned layer").

[0008] In this context, the layer structure is a structure that can be described as a series of thin films in one axis, usually perpendicular to the substrate surface, and has geometric shapes in other axes orthogonal thereto.

[0009] Thin film technology is used to produce such structures or resistor elements. In the context of the production method, the magnetization direction of the reference layer can be permanently established, which is usually denoted as pinning. In order to pin the ferromagnetic layer or reference layer, the ferromagnetic layer is usually coupled to an antiferromagnetic adjacent layer. In order to determine the magnetization direction, the resistor element, i.e. the layer structure, is heated above the "blocking temperature" at which the exchange coupling between the antiferromagnetic layer and the ferromagnetic layer disappears, which temperature is usually below the Curie temperature of the ferromagnetic layer. Once the desired temperature above the blocking temperature and below the Curie temperature is reached, the ferromagnetic layers are exposed to an external pinning field, thereby forcing the layers into a defined magnetization direction. To this end, the applied pinning field must be large enough to orient the ferromagnetic layers completely parallel to the pinning field. If the layer structure is cooled again and the temperature drops below the blocking temperature while the pinning field is applied, the magnetization direction is maintained.

[0010] In this context, the pinning field is also described as a locally acting magnetic field which penetrates the ferromagnetic layers of the layer structure in the desired pinning direction at right angles to the layer sequence (i.e. tangentially to the substrate surface) and constitutes a local magnetic field component. This is distinguished from the "preconditioning magnetic field" which is the overall orientation magnetic field, from which the pinning field is derived by means of a guiding magnetic field, for example by means of a ferromagnetic patterned element as a flux guiding element. The overall preconditioning magnetic field is typically stronger and can be oriented in a different direction than the local pinning field.

[0011] The disadvantage of such reference multilayer systems with only one ferromagnetic reference layer, also called "simple spin valves (SSV)", is only the low thermal stability. In particular, there is a risk that the pinning direction rotates in application due to high temperatures and the presence of magnetic fields. This effect leads to a drift in the behavior of sensors using these reference layers. This means that the lower the magnetic moment of the reference layer, the weaker the magnetic field can be injected and the layer rotates. In this case, it is therefore advantageous to keep the layer thickness of the reference layer small, so that any drift is also small. However, the magnetoresistance effect in such an SSV structure is relatively small. One advantage, however, lies in the fact that only low magnetic field strengths are required to align the reference layer.

[0012] In the case of the improved reference layer structure, in addition to the first ferromagnetic layer arranged on the antiferromagnetic layer, a second ferromagnetic layer is provided. Between the two ferromagnetic layers, a coupling layer is provided, which generates an antiparallel RKKY coupling (Ruderman-Kittel-Kasuya-Yoshida interaction) between the two ferromagnetic layers. This layer structure is also called "antiparallel coupled pinned layer spin valve (APP-SV)".

[0013] Since the magnetic moments of the two ferromagnetic layers are usually of approximately equal magnitude and the total magnetic moments of the ferromagnetic layers are cancelled to approximately zero due to the antiparallel alignment, in operation, the external magnetic field induces only a slight change in the magnetization direction of the reference layer system, which means that such a balanced APP-SV is stable even at relatively high temperatures. Compared with SSV, the magnetoresistance effect of APP-SV is larger.

[0014] However, a significant disadvantage is that, since the magnetic moments of the two ferromagnetic layers cancel each other (the total magnetic moment is approximately zero), pinning of the layer structure is only possible when the magnetic flux density is large enough to overcome the RKKY coupling between the ferromagnetic layers. For this purpose, a magnetic flux density of more than 1 T is required. This requires great efforts for the pinning process. Magnetic field sensors in which multiple layer stacks or resistor elements intended to have different magnetic orientations are provided cannot be produced at all or only require very great efforts to produce.

[0015] In order to establish the pinning direction, it is known to selectively heat a spatially confined area of ​​a substrate-carrying layer structure using a selective heating method, in particular using a laser, and to apply an external magnetic field in a desired direction parallel to the substrate surface for pinning purposes. Thus, the locally heated area can be pinned with the layer structure in the same direction. If different pinning directions are to be generated on the substrate, the method must be repeated multiple times with different external magnetic field alignments, wherein it is however not possible to pin spatially closely adjacent layer structures in different directions. On the other hand, for the construction of conventional direction-selective magnetic field sensors, layer structures with different preferred directions and subject to the same process engineering properties are required, and it is therefore desirable to pin the layer structures in different directions in closely adjacent layer structures.

[0016] Furthermore, sub-second laser pinning is disadvantageous for antiferromagnetic materials, which can only recrystallize into the antiferromagnetically ordered L10 phase during the pinning process, such as PtMn or NiMn. The recrystallization process typically lasts for many hours and cannot be achieved practically by laser local heating.

[0017] WO2016 / 078793A1 discloses a method and apparatus for multidirectional pinning of a magnetic field sensor, wherein a soft magnetic patterned element (i.e., a flux guiding element) is arranged adjacent to a layer structure, which injects a pre-conditioned magnetic field into the layer structure. The method proposed here enables the injection of a pre-conditioned magnetic field at right angles to the substrate surface, whereby any desired pinning direction tangential to the substrate surface can be established in a multi-directional pinning manner. Such multi-directional pinning makes it possible, for example, to produce a high-precision angle sensor with harmonic filtering of the sensor signal, as described, for example, in WO2016 / 083420A1. However, in practice, with this method, only low pinning flux densities can be achieved in the range far below 1T, making the method unusable for multilayer stacked structures with strong magnetic coupling.

[0018] US2015 / 0213815A1 discloses a magnetoresistive sensor comprising a layer stack arranged between a top shield and a bottom shield. The layer stack consists of an antiferromagnetic layer, a first ferromagnetic pinned layer, and a second ferromagnetic reference layer, wherein the two layers are coupled together antiparallel by a non-magnetic coupling layer. The quotient of the first magnetic moment of the first ferromagnetic layer and the second magnetic moment of the second ferromagnetic layer totals more than 1.1. However, in a magnetoresistive magnetic field sensor, the arrangement or production method of two adjacent, identically constructed TMR elements having different preferred directions on a substrate is not known.

[0019] US7,505,233B2 discloses a magnetic field sensor consisting of two sensors. The two sensors each include two ferromagnetic elements and a magnetoresistive element with sensitivity in the XY plane. The external magnetic field measured and guided in the Z direction cannot be measured with the magnetoresistive element. Because the magnetic field guided in the Z direction can be deflected in the X direction by two ferromagnetic elements, the magnetic field to be measured can be detected in the same direction with the help of the magnetoresistive element. In this regard, the ferromagnetic element is used to deflect the Z magnetic field to be measured and guide the magnetic flux into the XY plane. The magnetoresistive magnetic field sensor described therein does not have a layer structure with two ferromagnetic reference layers, and furthermore, a second adjacent and identically constructed TMR element with a different preferred direction on the substrate is not disclosed.

[0020] US2017 / 0328963A1 teaches a method for permanent magnetization of a ferromagnetic layer of a magnetic field sensor device. A pinning field is injected perpendicular to the chip substrate surface, wherein the shape of the border of the soft magnetic patterned element produces a horizontally oriented magnetic field component, which allows pinning in an adjustable direction in the chip substrate plane. This allows the magnetic field sensor elements to be pinned together in different axial directions and simultaneously pinned to the chip substrate surface, which is highly sensitive in two or more randomly curved directions. The document relates to a sensor layer structure with only a single pinned reference layer or "SSV layer stack", and does not disclose the application of an antiparallel reference layer or measures for pinning with reduced pinning field strength, nor does it suggest any associated structure.

[0021] US2015 / 0318465A1 relates to a magnetoresistive device comprising a magnetoresistive structure for measuring magnetic fields of TMR layer stacks with different widths. The magnetoresistive structure is constructed in the form of a layered double TMR layer with two TMR barriers in the layer stack. The free layer is arranged between the two TMR layer stacks, and the reference layer is also arranged above and below. US7605437B2 also relates to a layered double TMR layer with two TMR barriers in a layer stack.

[0022] DE112010003775T5 describes a field sensor which can also detect the Z component in the XY plane. To this end, the sensor contains a soft flux guide whose sole purpose is to transfer the perpendicular magnetic field into the plane. In this case, all magnetoresistive elements have the same pinning direction.

[0023] Similar to DE112010003775T5, US2018 / 0238972A1 relates to a field sensor for determining the Z component in the XY plane. It explains how to detect the Z component by guiding the field to be measured through a soft magnetic structure.

[0024] It is an object of the present invention to specify a layer structure for a magnetoresistive magnetic field sensor, a magnetoresistive magnetic field sensor and a method for producing such a layer structure or a magnetic field sensor which are improved with respect to the prior art. Summary of the invention

[0025] The object is achieved by an arrangement of at least two adjacent layer structures and a magnetoresistive magnetic field sensor using the arrangement, as well as by a method for producing the layer structure arrangement and by a method for producing a magnetoresistive magnetic field sensor according to the invention.

[0026] In an arrangement of at least two adjacently arranged layer structures, each layer structure includes at least one antiferromagnetic layer, a first ferromagnetic layer having a first magnetic moment, and a second ferromagnetic layer having a second magnetic moment, wherein there is exchange coupling between the antiferromagnetic layer and the first ferromagnetic layer, and wherein the second ferromagnetic layer is antiparallel coupled to the first ferromagnetic layer via a non-magnetic coupling layer arranged between the first and second ferromagnetic layers.

[0027] It is proposed that the magnetization (i.e., the pinning direction) of the corresponding first ferromagnetic layer and the corresponding second ferromagnetic layer of the adjacently arranged layer structure is different from each other, in particular, has an orientation substantially opposite to each other. Opposite means antiparallel orientation, i.e., the two pinning directions are rotated 180° relative to each other. Substantially opposite orientations also allow deviations from each other in an angular range of 160° to 200°, so that the pinning directions are oriented antiparallel to each other by substantially 180°, i.e., opposite orientations, and further deviations from the antiparallel orientation by up to ±20° are allowed.

[0028] Adjacent means that adjacent layer structures are arranged with their surfaces adjacent to one another on the substrate and that no further layer structures are arranged between adjacent layer structures. If a plurality of adjacent layer structures is mentioned, this means that each of the plurality of layer structures has at least one further layer structure between which no further layer structures are arranged. However, other structures may be located between two adjacent layer structures, such as conductor tracks or flux guiding elements, or soft magnetic patterned elements. It is also conceivable that a "virtual" layer structure is located between two adjacent layer structures, i.e. a layer structure whose resistance is not part of the sensor resistance, which in fact only exists as a placeholder layer structure and whose magnetization direction does not play any role in the resistance behavior of the sensor.

[0029] The antiferromagnetic layer, the first and second ferromagnetic layers and the coupling layer form a reference layer stack, which can be pinned by using the two ferromagnetic layers at very low magnetic field strengths. The combined total magnetic moment M of the two ferromagnetic layers MFM1 and MFM2 of the layer structure _APP_SV Obtained by the following formula:

[0030] M_ APP_SV = M FM1 – M FM2 <MSSV，

[0031] and is substantially smaller than the resultant moment M of a simple spin valve layer structure (SSV) with comparable magnetoresistance properties. SSV This layer structure can be expressed as an unbalanced antiparallel coupled pinned layer structure (APP - antiparallel coupled pinned layer spin valve).

[0032] With regard to the above-mentioned layer structures, in particular with regard to the balanced APP structure with an almost zero total magnetic moment, the necessary pinning field strength is reduced by a factor of 10. The layer structure according to the invention thus constitutes an optimization with regard to the possibility of performing the pinning process, the thermal and magnetic stability and the magnitude of the xMR effect. The significantly reduced strength of the resulting pinning field makes it possible for the first time to pin closely adjacent layer structures in different directions.

[0033] Advantageously, each layer structure has a circular or elliptical outer contour. Furthermore, adjacent layer structures can advantageously have the same structure with respect to the layer sequence, the layer film thickness and the layer materials used. The first ferromagnetic layers of at least two adjacent layer structures can have the same structure with respect to the material and layer thickness, and the second ferromagnetic layers of at least two adjacent layer structures can have the same structure with respect to the material and layer thickness. The nonmagnetic coupling layers of at least two adjacent layer structures can also have the same structure with respect to the material and layer thickness, and the antiferromagnetic layers of at least two adjacent layer structures can also be identical.

[0034] In an advantageous embodiment, for small layer structures, the center-to-center distance of adjacent layer structures is It can be equal to 50 μm or less, preferably 20 μm or less, and in particular 10 μm or less. Therefore, as a result of close spacing, different pinning directions can be achieved for layer structures of almost the same structure in the most limited space with similar material properties and production process conditions. This is because, for example, a soft magnetic patterned element can be introduced in a limited spacing region between adjacent layer structures. If this is passed through by a pretreatment magnetic field (the pretreatment magnetic field is preferably oriented perpendicular to the position of the layer stacking plane), a stray magnetic field is generated at the boundary of the patterned element, which passes through the adjacent layer structure perpendicularly to the boundary edge of the patterned element as a pinning field. Therefore, depending on the shape of the patterned element (rectangle, square, quadrilateral, polygon, circle, etc.), the most different pinning directions can be achieved, wherein the adjacent layer structures are only spaced less than 50 μm, preferably less than 20 μm, and in particular less than 10 μm. This distance can be considered as the minimum distance, wherein in the actual structure, a row of spaced layer structures are functionally arranged and electrically interconnected relative to each other, and wherein at least two adjacent layer structures (but not necessarily all layer structures) achieve this minimum distance.

[0035] The antiferromagnetic layer of each layer structure may be made of FeMn, IrMn, PtMn, NiMn, for example, and have a thickness between 5 nm and 30 nm.

[0036] The coupling layer of each layer structure which causes an antiparallel orientation of the second ferromagnetic layer with respect to the first ferromagnetic layer may consist, for example, of a metallic non-magnetic material, such as Ru or Rh, and have a thickness between 0.3 nm and 1.5 nm.

[0037] Preferred embodiments of the first and second ferromagnetic layers of each layer structure will be described in more detail below.

[0038] In an advantageous embodiment, the arrangement of the layer structures may include at least three, in particular four or more layer structures, which are arranged adjacent to each other, in particular separated from each other only by gaps or soft magnetic patterned elements. In particular, the magnetizations of the layer structures are arranged in pairs at an angle relative to each other, preferably at 90°, but also at 60°, 45°, 36°, 30°, 18° or 15°, and the magnetizations of the corresponding first ferromagnetic layer and the corresponding second ferromagnetic layer of each pair of adjacent layer structures in each pair are different from each other, and are preferably substantially opposite to each other, i.e., antiparallel to each other. In particular, the pinning directions of the magnetizations of a pair of relative layer structures are oriented to be approximately 180° relative to each other. Therefore, not only two mutually different pinning directions of adjacent layer structures can be achieved, in particular a relative orientation of substantially 180°. On the contrary, two by two or more pairs of layer structures, for example six by two pairs, can be provided with mutually different pinning directions, wherein in particular mutually corresponding pairs of layer structures provided with substantially 180° opposite pinning directions can be offset with respect to each other by any desired angle, for example 90°, but also by, for example, 15°, 18°, 30°, 36°, 45° or 60°. Thus, for example, an arrangement of layer structures can be produced for harmonic filtering for minimizing errors of rotation angle sensors, as described, for example, in WO2016 / 083420A1. Pairs of corresponding and relative layer structures can also have pinning directions that deviate from 180°, but can also have pinning directions that deviate from, for example, 160° or 200°. This can be achieved by a wedge-shaped external structure of the soft magnetic patterned element and can be used to filter high-frequency harmonic errors. Thus, the side surfaces of the patterned element may, for example, have a stepped angle profile, preferably forming an angle profile of one of 15°, 18°, 30°, 36°, 45°, 60°, 75° or 90°, wherein the opposite side surfaces may preferably be mirrored at the central axis. More than four pairs, for example six, eight or more pairs of layer structures may also preferably be arranged mirror-symmetrically or rotationally symmetrically relative to each other. In the case of six pairs, they may be offset by 30° relative to each other in each case, or four pairs may be offset by 45° relative to each other, wherein the corresponding pairs have 180° of opposite magnetization, i.e., pinning directions.

[0039] Starting from the above-described embodiment, two pairs of layer structures are preferably arranged adjacent to each other, wherein the first pair of layer structures are substantially oppositely magnetized and the second pair of layer structures are substantially oppositely magnetized in pairs. In addition, the magnetization direction of the second pair can be different from the magnetization direction of the first pair and preferably at an angle of 90°, 60°, 45°, 36°, 30°, 18° or 15°. Therefore, the pinning directions of the layer structures are in each case antiparallel in pairs and the pinning directions of the layer structures of adjacent pairs are away from each other by an angle of 90° or less. In each case, the individual layers of the layer structures of the layer structure pair can be identical to each other in terms of material and layer thickness.

[0040] In an advantageous embodiment, in each layer structure, the quotient of the first magnetic moment of the first ferromagnetic layer coupled to the antiferromagnetic layer and the second magnetic moment of the second ferromagnetic layer coupled to the first ferromagnetic layer in antiparallel may be different from 1, and may preferably be between 1.7 and 2.3 in total. Therefore, the first ferromagnetic layer coupled to the antiferromagnetic layer has a magnetic moment approximately twice that of the second ferromagnetic layer per exchange coupling, the second ferromagnetic layer being located on the side of the first ferromagnetic layer away from the antiferromagnetic layer and coupled to the first ferromagnetic layer in antiparallel via the nonmagnetic coupling layer.

[0041] The quotient of the first and second magnetic moments relates, for example, to the situation of the first and second ferromagnetic layers which have been deposited but not yet pinned, or can also relate to the situation after pinning of both layers.

[0042] According to an advantageous embodiment, each layer structure comprises a third ferromagnetic layer, which is arranged on the side of the second ferromagnetic layer facing away from the coupling layer, wherein a non-magnetic (in particular non-conductive) barrier layer (preferably MgO) is in particular arranged between the second ferromagnetic layer and the third ferromagnetic layer. The third ferromagnetic layer is usually in the form of a detection layer. The third ferromagnetic layer is preferably made of Co, CoFe, NiFe or CoNi, wherein one or more further elements (in particular boron or silicon) can optionally be added to the alloy. It can also consist of a multilayer system of different materials, which contains soft magnetic CoFe or NiFe. The barrier layer is particularly used to optimize the magnetoresistive tunneling effect.

[0043] Furthermore, according to the above-described embodiment, each layer structure can include at least one nonmagnetic covering layer, in particular a metal covering layer, which is arranged on the side of the third ferromagnetic layer facing away from the second ferromagnetic layer. The covering layer defines the layer structure relative to the adjacent structure located thereon and can in particular also be used to transmit the measurement current.

[0044] A terminating electrode layer, which can serve as a contact electrode for electrical contacting, can be located behind the cover layer of each layer structure or alternatively directly on the third ferromagnetic layer.

[0045] The terminating layer or covering layer is preferably identical over all layer structures with regard to material and layer thickness.

[0046] Each layer structure is advantageously applied to a substrate, wherein a "seed layer" can be applied between the substrate and the antiferromagnetic layer, which "seed layer" can promote the growth of the antiferromagnetic layer and can serve as a base electrode. In principle, the layer structure between the seed and the capping or terminating electrode layer can be applied to the substrate in the reverse order to that described here.

[0047] According to a further advantageous embodiment of the invention, in each layer structure, the first ferromagnetic layer consists of a first ferromagnetic material composition and the second ferromagnetic layer consists of a second ferromagnetic material composition, wherein the first ferromagnetic material composition is different from the second ferromagnetic material composition. The different material compositions, which may differ in terms of the chemical elements contained therein and / or their proportions, promote the formation of different magnetic moments of the ferromagnetic layers of the reference layer stack.

[0048] Advantageously, the first ferromagnetic material component is a CoFe alloy, wherein in particular the molar fraction or atomic percentage of Fe amounts to between 5% and 15%, and preferably to 10%.

[0049] Advantageously, the second ferromagnetic material component in each layer structure is a CoFeB alloy, in which, within the context of the corresponding tolerance deviations, the molar fractions or atomic percentages of Co and Fe in each case total 40% and the proportion of B totals 20%, wherein the tolerance deviations allow the corresponding ratios to deviate from the corresponding specified values ​​of the ratios by no more than 5 percentage points and preferably by no more than 2.5 percentage points.

[0050] The material compositions described above have proven to be particularly suitable for forming ferromagnetic layers having the desired magnetic moment ratio.

[0051] According to an advantageous embodiment, the first ferromagnetic layer in each layer structure has a first layer thickness , and the second ferromagnetic layer has a second layer thickness , where the quotient of the thickness of the first layer and the thickness of the second layer is / The total is between 1.2 and 2.5.

[0052] Advantageously, the thickness of the first layer in each layer structure is The total is between 0.5 nm and 2.0 nm, and preferably 1.2 nm, and the second layer thickness is selected , so that the quotient of the first and second magnetic moments amounts to between 1.7 and 2.3, wherein in particular the quotient of the magnetic moments is dependent on the condition of the deposited but not yet pinned first and second ferromagnetic layers.

[0053] For the two preferred material compositions mentioned above, namely Co90Fe10 for the first ferromagnetic layer and Co40Fe40B20 for the second ferromagnetic layer, the quotient of the first and second layer thicknesses preferably amounts to between 1.36 and 1.84, in particular 1.6.

[0054] According to an advantageous embodiment, the coupling layer of each layer structure comprises (in particular exclusively) Ru and has a thickness between 0.35 nm and 0.85 nm, and preferably has a thickness of 0.5 nm. Such dimensions of the coupling layer have proven to be particularly suitable.

[0055] The antiferromagnetic layer of each layer structure can advantageously be configured as a manganese alloy. Iridium-manganese (IrMn), platinum-manganese (PtMn), nickel-manganese (NiMn) or iron-manganese (FeMn) alloys or alloy mixtures thereof are particularly suitable for this. Manganese alloys, in particular platinum-manganese (PtMn) or nickel-manganese (NiMn), preferably exist in an ordered L10 phase. The L10 phase is an intermetallic ordered phase of a metal alloy, characterized by a regular mixed crystal structure, whereby the antiferromagnetic properties of the manganese alloy appear in a very pronounced manner. Even in the case of a pinning time lasting several hours and a temperature above the blocking temperature, such a manganese-based antiferromagnetic layer retains or achieves its excellent antiferromagnetic properties. For sputtered PtMn and NiMn layers, it is known that the preferred L10 crystal order is achieved only by heating for several hours at a temperature above 225°C, wherein such a crystal order achieves the best antiferromagnetic properties, and this is the result of a short heating that cannot be achieved using a selective laser pinning method.

[0056] Each layer structure is advantageously configured as a TMR system. To this end, the layer structure can have a lower base electrode and an upper termination electrode so that a current can flow through the layer structure in an electrically contactable manner and perpendicular to the layer structure (i.e. perpendicular to the substrate surface). The seed layer used as a base layer on the substrate to construct the layer structure, in particular an antiferromagnetic layer, is preferably formed as a conductive base electrode. In addition, in the first ferromagnetic layer, a magnetization can be applied in one pinning direction, and in the second ferromagnetic layer, a magnetization oriented antiparallel thereto can be achieved, so that a very high sensitivity to a change in resistance to an external magnetic field can be achieved in the pinning direction. The layer structure according to the present invention, including its advantageous embodiments, has proven to be particularly suitable for use in TMR-based magnetic field sensors, in particular in angle sensors and 2D field sensors. However, use in GMR-based magnetic field sensors is also possible as an alternative, wherein for this purpose, the base electrode and the termination electrode can be arranged laterally on the layer structure.

[0057] At least two adjacent TMR elements of identical construction can advantageously be arranged on a substrate, and the magnetization directions of the corresponding first ferromagnetic layer and the corresponding second ferromagnetic layer can be different from one another, in particular oriented oppositely or slightly differently with respect to 180°, but substantially antiparallel to one another. In this case, the adjacent TMR elements comprise the same layer package and are produced in the same deposition process, in particular simultaneously. In this case, the center-to-center distance of the adjacent TMR elements is It may preferably be equal to 50 μm or less, preferably 20 μm or less, and in particular 10 μm or less. In this case, in the at least temporary arrangement of the soft magnetic patterned element between two TMR elements, the pretreatment magnetic field may preferably be injected into the patterned element perpendicularly to the substrate surface. The stray field of the patterned element contains field components oriented parallel to the substrate surface and perpendicular to the side profile of the patterned element, and the stray field acts as an effective pinning field along the edge of the patterned element to orient the magnetic orientation of the first ferromagnetic layer. To this end, a relatively small center-to-center distance of the layer structure on the substrate or the TMR element may be selected. , and the patterned elements are constructed on the substrate in between, or are temporarily introduced, for example in the form of a punch. The pretreatment magnetic field can act on the entire surface of the substrate, wherein, at the location of the patterned elements corresponding to their edge orientation, pinning can be achieved in different directions parallel to the substrate surface due to the locally acting pinning field from the pretreatment magnetic field. In contrast to conventional laser pinning methods (in which the in-plane pinning field is injected parallel to the surface of the substrate (wherein the pretreatment magnetic field is therefore identical to the pinning field) and the blocking temperature is exceeded by brief laser heating), according to this further development, at low magnetic field strengths, integrated pinning in different directions of almost all layer structures on the substrate is possible for a period of time of any desired length. This means in practice that all TMR elements of all sensors on a wafer substrate can be pinned in one step.

[0058] The above arrangement of two or more adjacent, identically constructed and identically deposited TMR elements with pinning directions that are angled relative to each other, in particular antiparallel to each other, can also be implemented as envisaged without limiting the quotient of the first magnetic moment and the second magnetic moment to between 1.7 and 2.3. The key factor is that the magnetic moments of the two ferromagnetic layers allow pinning with relatively low magnetic field strengths, so that the above multi-directional pinning method using patterned elements can also be performed with TMR elements.

[0059] The magnetoresistive magnetic field sensor according to the present invention comprises a substrate, an arrangement of at least two or more layer structures arranged adjacent to each other on the substrate according to one of the aforementioned embodiments, and at least one at least temporarily introducible soft magnetic patterned element arranged adjacent to or partially overlapping the corresponding layer structure, wherein the patterned element is configured and arranged to affect the pre-processing magnetic field penetrating into the patterned element, thereby having the following effect: at least in the first ferromagnetic layer of the adjacent layer structure, the magnetic field component that is oriented differently and extends parallel to the surface of the layer structure becomes effective as a stray magnetic field of the patterned field to serve as a pinning field. The pre-processing magnetic field is preferably injected into the patterned element perpendicular to the surface of the substrate. Typically, after the pinning operation, the temporarily introduced patterned element is removed again. Typically, the magnetic field sensor includes one or more Wheatstone measurement bridges of magnetoresistive bridge resistors. Each bridge resistor includes at least one, in particular a plurality of layer structures connected in series, which generally have magnetization directions of substantially the same orientation. In this regard, the layer structures arranged at least in pairs adjacent to each other can be interconnected in various bridge resistors of the Wheatstone measurement bridge in each case.

[0060] For example, a soft magnetic patterned element made of a photolithographically patterned nickel-iron alloy is arranged in such a way that a pretreatment magnetic field is simultaneously and perpendicularly injected into the patterned element to the surface of the corresponding layer structure, and a magnetic field component parallel to the surface of the corresponding layer structure is also generated at the position of the layer structure, which penetrates the first and second ferromagnetic layers at least in an appropriate position. In this way, adjacent layer structures can be penetrated by pinning fields of different orientations, preferably substantially opposite. The pretreatment magnetic field can be, for example, a uniform magnetic field, which strikes vertically on the surface of the layer structure, and due to the magnetic field characteristics and geometric configuration of the patterned element, it exists in the form of an inhomogeneous stray field also parallel to the surface of the layer structure at the boundary edge, and causes the pinning of the adjacent layer structure. In this way, any desired pinning direction can be provided in the corresponding layer structure, wherein a single patterned element can also pin multiple layer structures simultaneously and also in different directions. Different pinning directions depend essentially on the contour shape of the patterned element, which defines the patterned element relative to the surface of the substrate.

[0061] The arrangement of soft magnetic patterned elements on a magnetoresistive magnetic field sensor and a corresponding method for producing a magnetic field sensor are described by way of example in WO 2016 / 078793 A1, which describes the pinning of the layer structure of the magnetic field sensor, the entire disclosure of which is included in the present application by reference. Different configurations of soft magnetic patterned elements are also known from this document.

[0062] Surprisingly, it was found that the soft magnetic patterned element as described in WO 2016 / 078793 A1 is particularly suitable for pinning layer structures on magnetic field sensors, which can be attributed to the fact that only a relatively low preconditioning magnetic field with a strength of less than 130 mT is required for pinning the layer structure according to the invention, and the pinning field generated in the process (which typically has a strength of less than 80%, typically less than 50% of the strength of the preconditioning magnetic field) has a significantly lower strength again. In particular, a plurality of layer structures according to the invention can be provided on a magnetic field sensor, which structures are magnetized in different spatial directions and in particular form a Wheatstone bridge, as described, for example, in WO 2016 / 083420 A1.

[0063] The method according to the invention for producing an arrangement of a layer structure according to one of the above aspects comprises the following steps:

[0064] - applying the layers to the substrate between the capping layer and the seed layer in the order stated or in reverse,

[0065] heating the layer structure to a temperature above a blocking temperature at which exchange coupling between the antiferromagnetic layer and the first ferromagnetic layer is cancelled,

[0066] - injecting a pretreatment magnetic field, particularly oriented perpendicularly to the surface of the substrate (110), into the heating

[0067] to establish a pinning field having different magnetization directions of the first ferromagnetic layers of the adjacent layer structures at least during a period in which the temperature of the layer structure is above the blocking temperature, and

[0068] - Cooling the layer structure to a temperature below the barrier temperature.

[0069] In a first step, an arrangement of at least two, in particular multiple magnetoresistive layer structures, preferably a GMR or TMR layer structure, is applied adjacent to each other, which has a layer structure corresponding to one or more of the above aspects. In particular, the layers of all layer structures are deposited simultaneously in the same coating process, thereby achieving the same layer thickness and material for adjacent layer structures. For all layer structures, all patterning processes can also preferably be carried out in parallel and simultaneously, rather than sequentially, which means that the first layer structure is not formed first and then the second layer structure is formed. It has been proven that it is very advantageous to produce all layer structures in the same coating process and not to carry out a sequence or different treatment of different layer structures on the substrate. In order to orient one or more first ferromagnetic layers, a temperature above the blocking temperature is applied so that the exchange interaction between the first ferromagnetic layer and the antiferromagnetic layer is offset. Then, the ferromagnetic layer is no longer pinned by the adjacent antiferromagnetic layer and behaves in a similar manner to the free layer. Then an external magnetic field is injected, which is also referred to as a pretreatment magnetic field, in which the field lines of the magnetic field are guided in such a way that it enters the layer structure as a pinning field parallel to the layer plane at a suitable point and causes an adjustable magnetization of the first ferromagnetic layer there.

[0070] Advantageously, the arrangement of the layer structure is heated to at least 260° C., preferably to 280° C., which is sufficient, in particular for iridium-manganese, to achieve a blocking temperature and thus enable pinning, i.e. an orientation of the magnetization of the first ferromagnetic layer. In the case of an antiferromagnetic layer comprising PtMn or a NiMn alloy, typical temperatures are preferably above 300° C., in particular between 300° C. and 350° C.

[0071] The magnetic flux density of the injected pretreatment magnetic field is not more than 200 mT and preferably not more than 100 mT, so that the TMR element or GMR element based on the antiparallel coupled spin valve layer structure (APP-antiparallel coupled pinned layer spin valve) can be easily and cheaply produced.

[0072] The time period for the pinning field injection into the arrangement of the layer structure heated above the blocking temperature is at least 1 hour, preferably at least 5 hours, particularly preferably at least 12 hours. The very long injection time at high temperature leads to an ordered orientation of the L10 layer of the antiferromagnetic layer, thus significantly improving the antiferromagnetic properties.

[0073] The method according to the invention for producing a magnetoresistive magnetic field sensor according to the invention comprising at least one soft magnetic patterning element according to the above-described aspect comprises the above-described method according to the invention for producing an arrangement of a layer structure comprising an advantageous configuration of the method and at least temporary application of at least one patterning element.

[0074] According to the invention, the pretreatment magnetic field is injected as a pinning field via the patterned element into adjacent layer structures with different magnetization directions. Once the pinning is terminated, the patterned element is preferably removed again so that it can be temporarily applied to the substrate, for example, using conventional photolithography and electroplating methods, and can be removed again using etching methods or material removal methods. It is also conceivable to temporarily lower the patterned element in the form of a punch above the substrate and inject the pretreatment magnetic field in this way. Alternatively, the soft magnetic patterned element can also be kept at least in a position as a flux guiding element for the external magnetic field.

[0075] In an advantageous further development of the above-described production method, an arrangement of at least two adjacent mutually spaced layer structures can be applied to the substrate, and a patterned element is at least temporarily applied between the layer structures. During heating above the blocking temperature, a pretreatment magnetic field can be injected into the patterned element or multiple patterned elements perpendicular to the surface of the substrate, so that the non-uniform stray magnetic field generated by the patterned element provides a desired orientation of the pinning field substantially parallel to the substrate surface. The orientation of the pinning active magnetic field component parallel to the substrate surface with the pretreatment magnetic field depends on the edge geometry of the patterned element, so that the orientations of the pinning fields of adjacent layer structures are preferably different from each other, in particular substantially oppositely oriented. By this further development of the production method, although the reference layer of the GMR or TMR element contains two antiparallel coupled ferromagnets, the GMR and TMR elements can be fixed in a spatially closely adjacent arrangement in different preferred directions, wherein the pretreatment magnetic field is less than 200 mT, preferably less than 100 mT.

[0076] By combining these methods, in particular the possibility of pinning over long time periods of minutes to hours, and a specific sequence of layer structures with a closely adjacent arrangement and materials (material selection), it is thus possible to use thermally particularly robust antiferromagnetic materials such as PtMn and NiMn in an optimized L10 phase, additionally with a first and a second ferromagnetic layer with a thermally robust antiferromagnetic coupling in the sensor, and additionally place different TMR or GMR elements in a confined space, which behave and are generated identically outside the pinning direction of the reference layer, which partially differ in direction, preferably are oriented substantially oppositely, i.e. within an angular range of 160° to 200° relative to one another.

[0077] Further advantageous configurations of the layer structure, the magnetoresistive magnetic field sensor and the production method are revealed by the description, the drawings and the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Further advantages are disclosed by the present drawings and the associated description of the drawings. The drawings show exemplary embodiments of the invention. The drawings, the description and the claims contain many features in combination. A person skilled in the art will also readily consider the features individually and combine them into meaningful further combinations.

[0079] In the attached picture:

[0080] Figure 1 Is a schematic diagram of a layer structure arranged according to an exemplary embodiment of the present invention;

[0081] Figure 2a , 2b is a schematic cross-sectional representation of a layer structure of a TMR comprising an embodiment of an arrangement of these layer structures according to the present invention;

[0082] Figure 3 Schematic cross-sectional representation of an embodiment of an arrangement of a pair of layer structures as a TMR element according to an exemplary embodiment of the present invention;

[0083] Figure 4 is a perspective view of a magnetoresistive magnetic field sensor having an arrangement of a plurality of layer structures and a soft magnetic patterned element according to an exemplary embodiment;

[0084] Figure 5 yes Figure 4 Schematic diagram of the pinning step of the magnetic field sensor shown;

[0085] Figure 6 shows a plan view of a magnetoresistive magnetic field sensor during a pinning process according to an exemplary embodiment;

[0086] Figures 7a-7d Schematic diagram showing an embodiment of an arrangement of layer structures with different pinning directions.

[0087] In the drawings, the same elements are denoted by the same reference numerals. DETAILED DESCRIPTION

[0088] Figure 1 An embodiment of a layer structure 100 for an arrangement according to the invention is shown, which in this exemplary embodiment is described as a TMR system. For the configuration of a GMR system as a modification according to the exemplary embodiment, the changes that must be made with respect to the TMR system are generally known to a person skilled in the art.

[0089] The individual layers of the layer structure 100 are applied using coating methods generally known and customary in semiconductor technology, for example chemical or physical vapor deposition methods.

[0090] The multiple layer structure 100 is applied to a semiconductor substrate or substrate 110. First, a seed layer 112 is applied to the substrate 110, which seed layer is selected so that a subsequently applied antiferromagnetic layer 114 with optimal properties grows. The seed layer 112 is characterized by sufficient conductivity and the smallest possible surface roughness so that as a base electrode 132, it forms a first electrical connection point.

[0091] An antiferromagnetic layer 114 (also indicated as pinning layer) is applied to the seed layer 112. The antiferromagnetic layer 114 consists, for example, of FeMn, NiMn, IrMn or PtMn, with a typical layer thickness of between 5 nm and 30 nm.

[0092] A first ferromagnetic layer 116 is then applied onto the antiferromagnetic layer 114, the antiferromagnetic layer being applied from a CoFe alloy, typically Co90Fe10 (expressed in mass percent), with a thickness of 0.5 nm to 2.0 nm, typically 1.2 nm.

[0093] An intermediate or coupling layer 118 adjoins the first ferromagnetic layer 116, for example made of Ru with a thickness between 0.35 nm and 0.85 nm, typically 0.5 nm. The coupling layer 118 induces an antiparallel magnetic orientation of the second ferromagnetic layer 120 relative to the first ferromagnetic layer 116 through RKKY coupling.

[0094] A second ferromagnetic layer 120 made of a CoFeB alloy (typically Co40Fe40B2O) is deposited on the coupling layer 118. The layer thickness of the second ferromagnetic layer 120 is selected so that the magnetic moments of the deposited, not yet pinned ferromagnetic layers 116, 120 adopt the desired ratio. This ratio (more precisely, the quotient of the magnetic moment M1 of the first ferromagnetic layer 116 and the magnetic moment M2 of the second ferromagnetic layer 120, M1 / M2) can advantageously adopt a value between 1.7 and 2.3, typically 2.0. With regard to the above-mentioned material composition of the ferromagnetic layers 116, 120, this corresponds to a ratio or quotient, D1 / D2, of the physical thickness D1 of the first ferromagnetic layer 116 and the physical thickness D2 of the second ferromagnetic layer 120 in the range between 1.36 and 1.94, typically 1.6.

[0095] The antiferromagnetic layer 114, the first ferromagnetic layer 116, the coupling layer 118 and the second ferromagnetic layer 120 together form a reference layer stack 126. In order to achieve different magnetic moments, the two ferromagnetic layers 116, 120 can have different material compositions and / or different layer thicknesses. For this purpose, the first ferromagnetic layer 116 is shown to have a thickness of And the ferromagnetic layer 120 has a thickness , where reduced thickness indicates reduced magnetic moment.

[0096] A barrier layer 122 in the form of a non-conductive layer of MgO is additionally applied on top of the reference layer stack 126 or the second ferromagnetic layer 120, wherein its thickness is selected such that the magnetoelectric tunneling effect, which is typically between 20% and 200%, and the tunnel resistance of the entire layer stack, which can typically be between 100Ω and 30kΩ, are optimized for the relevant application. Finally, a third ferromagnetic layer 124 comprising CoFe, Co or NiFe is applied to the barrier layer 122, wherein one or more other elements (e.g. B) can additionally be added to the alloy. The third ferromagnetic layer 124 is configured such that the TMR effect is at a maximum.

[0097] Further ferromagnetic layers with the same or different material composition or thickness may optionally be applied to the third ferromagnetic layer 124 so that the magnetic properties of the third electromagnetic layer 124 optionally comprising the further ferromagnetic layer may be optimized as a detection layer.

[0098] Furthermore, one or more non-magnetic metallic termination layers or cover layers 128 may be provided on the layer structure 100 in order to define the layer structure 100 with respect to environmental influences or adjacent elements situated thereon.

[0099] Figure 2a Shows relative to Figure 1 The layer structure 100 of the present invention is added as an embodiment of a TMR element 140 for the arrangement according to the invention. It comprises a base electrode layer 132 and a terminal cover electrode layer 130 directly on the substrate 110 as well as a cover layer 128. The electrodes 130, 132 are used for the electrical connection of the TMR element, for example for the connection in the measuring bridge configuration of the magnetic field sensor 10. Due to the electrode configuration in the Z direction perpendicular to the substrate 110, the layer structure 100 can take the form of a TMR element 140, while a lateral electrode configuration can also provide a GMR element.

[0100] The insulation layer 134 covers the side surfaces of the TMR element 140 , so that during the construction a defined layer sequence and a lateral delimitation relative to adjacent layer structures can be achieved.

[0101] The layers 114 - 124 may also be applied to the substrate 110 in reverse order between the cap layer 128 and the seed layer 112 , ie starting with the third ferromagnetic layer 124 and ending with the antiferromagnetic layer 114 or a further cap layer 128 and the base electrode 132 .

[0102] The seed layer 112 can also be used as the bottom electrical connection point of the base electrode 132, or alternatively, the base electrode 132 can be constructed separately from the seed layer 112 directly on the substrate 110 and vertically adjacent to the seed layer 112. On the cover layer 128, a termination electrode 130 can be applied as the top connection point of the layer structure. Thus, the current can be vertically guided through the layer structure so that the layer structure is provided as a magnetoresistive resistor with a preferred magnetization direction defined according to the magnetic orientation of the two ferromagnetic layers. The resulting magnetoresistive resistor layer arrangement can be used for a magnetic field sensor arrangement or a magnetic storage arrangement with high sensitivity requirements.

[0103] Figure 2b Shown on a smaller scale Figure 2a , where a more extensive insulating layer 134 encapsulates the TMR element 140 and insulates and passivates it from adjacent structures on the substrate 110 .

[0104] Figure 3 is a schematic diagram of an embodiment of an arrangement of two adjacent TMR elements 140 with a center axis spacing in the range of 5 μm to 50 μm, wherein each TMR element 140 substantially corresponds to Figure 2a However, the base electrode 132 is implemented as a conductive seed layer 112, so that the seed layer 112 is simultaneously used for the electrical connection of the TMR element 140. For use in a magnetic field sensor, different pinning directions of the magnetoresistive resistors of the measuring bridge are required, which ideally have the same construction to make the resistance behavior uniform and are very closely adjacent in space. This is in Figure 3 is realized because the center-to-center distance of the reference layer stack 126 is The total is between 5 μm and 50 μm, and the pinning directions of adjacent reference layer stacks 126 are opposite, i.e. 180° antiparallel orientation. Slight deviations of ±20° from 180° are also assumed to be substantially antiparallel. Therefore, the resistances of the two stacks behave oppositely to each other in the case of an external magnetic field.

[0105] So that the two pinning directions can be oriented differently, the soft magnetic patterned element 18 can be advantageously temporarily introduced between the two TMR elements 140 and magnetized in the Z direction by a pre-treatment magnetic field Hz, which Figure 4 is shown in perspective in Figure 5 Schematically shown in a side view.

[0106] According to an exemplary method for producing a layer structure according to the present invention, the layer structure 100 can be subjected to a pinning process. To this end, the layer structure 100 is heated to a temperature above the blocking temperature of the layer structure 100, preferably to more than 260° C., typically 280° C. The layer structure 100 is then exposed to a pretreatment magnetic field Hz having a relatively low magnetic field strength of not more than 130 mT and preferably not more than 100 mT, wherein the field lines of the pinning field M0 derived therefrom and scattered by the patterned element extend parallel to the surface of the layer structure 100.

[0107] The pinning of the layer structure can be carried out particularly advantageously with the aid of one or more soft magnetic patterned elements 18. The corresponding magnetic field sensors are arranged at Figure 4 is shown in perspective view and in Figure 5 Schematically shown in a side view with a graphical representation of the field intensity distribution of the pinning field. Figure 6 As shown in the plan view in FIG. 1 , the magnetoresistive magnetic field sensor 10 with the applied patterned element 18 includes a Figure 1 The magnetic field sensor 10 comprises a semiconductor chip substrate or substrate 12 on which the resistor elements 14 are arranged. The resistor elements can be interconnected to form a Wheatstone measurement bridge. For magnetic pre-orientation or "pinning" of the ferromagnetic layers of the resistor elements 14, a pre-conditioning magnetic field Hz 38 is used, which is oriented perpendicular to the surface 36 of the substrate 12.

[0108] The magnetic field 38 is emitted by the magnetic pole (not shown), passes through the substrate 12 and is absorbed again by the anti-polar surface 58 (also not shown) arranged below the substrate 12. The pretreatment magnetic field Hz38 enters vertically into the soft magnetic patterned element 18 and is guided therein in a concentrated manner, where it exits as a pinning field M060, i.e. as an inhomogeneous stray field at right angles to the surface 44 of the patterned element 18 and substantially parallel to the surface of the substrate 110.

[0109] like Figure 5 As shown in the diagram, the patterned element 18 guides the pre-treatment magnetic field Hz38 in such a way that the pre-treatment magnetic field Hz38 exits as a pinning field M060 at the boundary edge 20 parallel to the substrate surface 36 and passes through the resistor element 14 parallel to the surface of the substrate 110, the resistor element 14 being implemented as a TMR element 140. An improved penetration of the resistor element 14 is achieved, in particular because a temperature above the blocking temperature of the antiferromagnetic layer of the resistor element 14 is established so as to improve the flux guidance through the resistor element 14.

[0110] In an advantageous embodiment, the boundary edge 20 of the patterned element 18 overlaps the boundary edge 22 of the resistor element 14. Therefore, the resistor element 14 is traversed over its entire width by a magnetic field which also has a component parallel to the substrate surface 36. Finally, the magnetic field lines are directed through the substrate 12 onto the counterpolar surface 58, so that different pinning directions can be established depending on the orientation of the boundary edge 20 of the patterned element 18 on the substrate 12.

[0111] Figure 6 The production of a composite angle sensor consisting of two Wheatstone measuring bridges for measuring the two rectilinear magnetic field components X and Y of the magnetic field sensor 10 is shown. For better illustration, the wiring levels for connecting resistor elements in a series circuit or a parallel circuit, for example to form a Wheatstone measuring bridge, are not shown. Likewise, the terminals or pads for contacting the outside world are not shown. Figure 6 The pinning step of the magnetic field sensor 10 is shown, wherein a plurality of resistor elements 14 (e.g. TMR resistor elements 14 corresponding to the arrangement of the layer structure 140 of FIG. 2 ) are arranged on the substrate surface 36 of the substrate 12. At least for pairs of angled TMR elements 140, the elements are spaced apart relative to each other at a center-to-center distance arrangement, where they are pinned antiparallel. In these spacing regions In the embodiment, a soft magnetic patterned element 18 of, for example, NiFe, is applied partially overlappingly with respect to the boundary edge 22 of the resistor element 14, and its boundary edge 20 at least partially covers the boundary edge 22 of the resistor element 14. By applying a magnetic field oriented perpendicular to the substrate surface 36 (as indicated by the small arrow), a boundary edge stray field 46 of the patterned element 18 is generated, which performs pinning of the resistor element 14. After pinning, the patterned element 18 can be removed again from the substrate 110 using a material removal method.

[0112] Figure 6 It is shown that, thanks to the present invention, complex sensors with multiple pinning directions can be produced using thermally robust antiferromagnets such as PtMn or NiMn and thermally robust layer stacks with antiferromagnetically coupled reference layers. All sensors built on a wafer substrate can be pinned simultaneously in any desired direction for a long time in one step, which enables economically viable implementations even when using antiferromagnets that require long pinning to exhibit the preferred L10 phase.

[0113] FIG7 shows different arrangements of layer structures 100 configured as TMR elements 140. In order to achieve different pinning directions M0 during production, soft magnetic patterned elements 18 are temporarily introduced into the space between multiple pairs of layer structures 100. At a temperature above the blocking temperature, the patterned elements 18 are exposed to a pre-treatment magnetic field Hz38 oriented perpendicular to the stacking plane of the layer structure 100, wherein a stray magnetic field pointing at a right angle away from the surrounding edge is formed as a pinning field M060. The pinning field M060 is in the stacking plane of the patterned element and is magnetized, i.e., pins the corresponding ferromagnetic layer 116 in respectively different directions and thus also pins the layer 120 of the layer structure 100.

[0114] Figure 7a The center-to-center distance Schematic diagram of a spaced-apart row of six, respectively paired, TMR elements 140 which are pinned oppositely by means of a rectangular patterned element 18. In a series circuit of the TMR elements, two bridge resistors of a half bridge of a magnetic field sensor 10 with opposite magnetic field sensitivities can thus be formed.

[0115] Figure 7b is a schematic diagram of a plurality of arrangements of TMR elements 140 which may be used, for example, in magnetoresistive angle sensors and interconnected for this purpose. Figure 7a The TMR elements 140 are arranged in pairs to form bridge resistors sensitive in the X direction and the Y direction. The patterned elements temporarily introduced between the TMR elements 140 are offset by 90° relative to each other to provide a pinning field M060 in the X or Y direction.

[0116] Figure 7c and Figure 7d A further embodiment of an arrangement of a layer structure 100 as TMR elements 140 is shown, between which patterned elements 18 with angled boundary edges 20 are arranged. Figure 7c In the embodiment, the patterned element 18 is hexagonal, wherein two pairs of pinning directions offset by 180° may be provided. These pairs may have pinning directions that differ by 90°, 60°, 45°, 36°, 30°, 18° or 15°.

[0117] Figure 7d The patterned element is configured as a tetradecagon, wherein two mirror-symmetrically opposite boundary edges 20 have three symmetrical angle increments of -60°, -45°, 30°, 0°, 30°, 45° and 60°. , and In this regard, for example for harmonic filtering, the series-connected TMR elements may have different pinning directions, in particular when used as angle sensors. The number of TMR elements 140 shown for each resistor arrangement is schematic, and typically the number of TMR elements in each bridge resistor is significantly higher than shown.

[0118] In principle, the layer structure 100 ( Figure 1 ) can also be pinned in any other suitable manner. The arrangement of the soft magnetic patterned element 18 can also be configured as a punch that is briefly lowered into the substrate structure from above.

[0119] Reference numerals list

[0120] 10 Magnetic Field Sensor

[0121] 12 substrate

[0122] 14 Resistor element

[0123] 18 Soft magnetic patterned components

[0124] 20 Boundary edges of patterned components

[0125] 22 Boundary edge of resistor element

[0126] 36 substrate surface

[0127] 38 Pre-treatment magnetic field

[0128] 42 Baseboard bottom

[0129] 44 Patterning the surface of components

[0130] 46 Boundary edge stray field

[0131] 58 Antipolar surface

[0132] 60 Pinning Field

[0133] 100-layer structure

[0134] 110 substrate

[0135] 112 seed layer

[0136] 114 Antiferromagnetic layer

[0137] 116 First ferromagnetic layer

[0138] 118 Coupling layer

[0139] 120 Second ferromagnetic layer

[0140] 122 Barrier layer

[0141] 124 Third ferromagnetic layer, detection layer

[0142] 126 Reference layer stacking

[0143] 128 Overlay

[0144] 130 terminal electrode

[0145] 132 base electrode

[0146] 134 Insulation layer

[0147] 140 TMR components

[0148] HZ Pre-treatment Magnetic Field in Z Direction

[0149] The width of the first ferromagnetic layer

[0150] The width of the second ferromagnetic layer

[0151] Center distance between adjacent layers

[0152] M0 Pinning Field

[0153] First side angle

[0154] Second side angle

[0155] The third side angle

Claims

1. An arrangement of at least two adjacently arranged and identically constructed layer structures (100) for a magnetoresistive magnetic field sensor (10), each layer structure (100) comprising at least one antiferromagnetic layer (114), a first ferromagnetic layer (116) having a first magnetic moment, and a second ferromagnetic layer (120) having a second magnetic moment, wherein: There is exchange coupling between the antiferromagnetic layer (114) and the first ferromagnetic layer (116), and the second ferromagnetic layer (120) is antiparallel coupled to the first ferromagnetic layer (116) via a non-magnetic coupling layer (118) arranged between the first ferromagnetic layer (116) and the second ferromagnetic layer (120), wherein the magnetization intensities of the corresponding first ferromagnetic layer (116) and the second ferromagnetic layer (120) of the layer structure (100) arranged adjacently with a center-to-center distance ΔD of 50 μm or less are different from each other, characterized in that all corresponding ferromagnetic layers (116, 120) of the adjacent layer structure (100) are established simultaneously in one pinning step.

2. The arrangement of the layer structure (100) according to claim 1, characterized in that The magnetization strengths of the corresponding first ferromagnetic layer (116) and second ferromagnetic layer (120) have substantially opposite orientations to each other.

3. The arrangement of the layer structure (100) according to claim 1, characterized in that At least four or more layer structures (100) are arranged adjacent to each other, separated from each other only by a gap or a soft magnetic patterned element, and have different magnetization intensities, wherein the magnetization intensities of pairs of opposing layer structures (100) have substantially opposite orientations to each other, and wherein the magnetization intensities of each pair of layer structures (100) are at an angle to each other.

4. The arrangement of the layer structure (100) according to claim 3, characterized in that The magnetizations of the respective pairs of layer structures (100) are at an angle of 90°, 60°, 45°, 36°, 30°, 18° or 15° to one another.

5. The arrangement of the layer structure (100) according to claim 1 or 2, characterized in that A center-to-center distance ΔD between at least two adjacently arranged layer structures (100) is 20 μm or less.

6. The arrangement of the layer structure (100) according to claim 1, characterized in that In each layer structure (100), a quotient of the first magnetic moment and the second magnetic moment of each layer structure (100) is different from 1.

7. The arrangement of the layer structure (100) according to claim 6, characterized in that The quotient is between 1.7 and 2.

3.

8. The arrangement of the layer structure (100) according to claim 1, characterized in that Each layer structure (100) comprises a third ferromagnetic layer (124) which is arranged on a side of the second ferromagnetic layer (120) remote from the coupling layer (118), wherein a nonmagnetic barrier layer (122) is arranged between the second ferromagnetic layer (120) and the third ferromagnetic layer (124).

9. The arrangement of the layer structure (100) according to claim 8, characterized in that Each layer structure (100) comprises at least one nonmagnetic cover layer (128) which is arranged on a side of the third ferromagnetic layer (124) facing away from the second ferromagnetic layer (120).

10. The arrangement of the layer structure (100) according to claim 1, characterized in that In each layer structure (100), the first ferromagnetic layer (116) consists of a first ferromagnetic material composition and the second ferromagnetic layer (120) consists of a second ferromagnetic material composition, wherein the first ferromagnetic material composition is different from the second ferromagnetic material composition.

11. The arrangement of the layer structure (100) according to claim 10, characterized in that In each layer structure (100), the first ferromagnetic material component is a CoFe alloy.

12. The arrangement of the layer structure (100) according to claim 11, characterized in that The mole fraction of Fe in the first ferromagnetic material is between 5% and 15%.

13. The arrangement of the layer structure (100) according to claim 10, characterized in that The second ferromagnetic material component in each layer structure (100) is a CoFeB alloy, wherein the molar fractions of Co and Fe in each case add up to 40% and the fraction of B adds up to 20% with corresponding tolerance deviations, wherein the tolerance deviations allow the respective fractions to deviate from the respective specified values ​​of the fractions by no more than 5 percentage points.

14. The arrangement of the layer structure (100) according to claim 1, characterized in that The first ferromagnetic layer (116) in each layer structure (100) has a first layer thickness Δl1 and the second ferromagnetic layer (120) has a second layer thickness Δl2, wherein the quotient Δl1 / Δl2 of the first layer thickness and the second layer thickness is between 1.2 and 2.

5.

15. The arrangement of the layer structure (100) according to claim 14, characterized in that The first layer thickness Δl1 in each layer structure (100) is between 0.5 nm and 2.0 nm, and the second layer thickness Δl2 is selected such that the quotient of the first magnetic moment and the second magnetic moment is between 1.7 and 2.

3.

16. The arrangement of the layer structure (100) according to claim 1, characterized in that In each layer structure (100), the coupling layer (118) consists of ruthenium and has a thickness between 0.35 nm and 0.85 nm.

17. The arrangement of the layer structure (100) according to claim 1, characterized in that In each layer structure (100), the antiferromagnetic layer (114) is a manganese alloy, an iridium-manganese (IrMn) alloy, a platinum-manganese (PtMn) alloy, a nickel-manganese (NiMn) alloy, an iron-manganese (FeMn) alloy or an alloy mixture thereof, wherein the manganese alloy exists in an ordered L10 phase.

18. The arrangement of the layer structure (100) according to claim 1, characterized in that The arrangement of the layer structures (100) is arranged on a substrate (110), wherein each layer structure (100) takes the form of a TMR element (140) having a lower base electrode (132) and an upper termination electrode (130), wherein in the first ferromagnetic layer (116), a magnetization is applied in a pinning direction and in the second ferromagnetic layer (120), a magnetization oriented antiparallel thereto is established.

19. A magnetoresistive magnetic field sensor (10), comprising a substrate (110), an arrangement of at least two adjacently arranged and identically constructed layer structures (100) according to claim 1 on the substrate (110), and at least one at least temporarily introduceable soft magnetic patterned element (18), the soft magnetic patterned element (18) being arranged adjacent to the corresponding layer structure (100) or partially overlapping two or more adjacently arranged layer structures (100), wherein: The soft magnetic patterned element (18) is configured and arranged to influence a pre-treatment magnetic field Hz (38), which penetrates into the soft magnetic patterned element (18) so that at least the magnetic field components with different orientations in the first ferromagnetic layer (116) of the adjacent layer structure (100) become effective as stray magnetic fields of the soft magnetic patterned element (18), so that the stray magnetic field of the soft magnetic patterned element (18) serves as a pinning field M0 (60), which extends parallel to the surface of the layer structure (100), wherein the pre-treatment magnetic field Hz (38) can be injected into the soft magnetic patterned element (18) perpendicular to the surface of the substrate (110).

20. A method for producing an arrangement of a layer structure (100) according to claim 1, comprising the steps of applying the layer to a substrate (110) between a cover layer (128) and a seed layer (112), heating the layer structure (100) to a temperature above a blocking temperature at which the exchange coupling between the antiferromagnetic layer (114) and the first ferromagnetic layer (116) is cancelled, injecting a preconditioning magnetic field Hz (38) simultaneously into the heated layer structure (100) to establish a pinning field M0 (60) with different magnetization directions parallel to the layer plane of at least the first ferromagnetic layer (116) of adjacent layer structures (100) at least for a period of time during which the temperature of the layer structure (100) is greater than the blocking temperature, and cooling the layer structure (100) to a temperature below the blocking temperature, wherein: The pre-treatment magnetic field Hz (38) is oriented perpendicular to the surface of the substrate (110).

21. The method according to claim 20, wherein: The arrangement of the layer structure (100) is heated to at least 260°C.

22. The method according to claim 20, wherein: The magnetic flux density of the injected pre-treatment magnetic field Hz (38) is not greater than 200 mT.

23. The method according to claim 20, wherein: The pre-treatment magnetic field Hz (38) is injected into the layer structure (100) heated to above the blocking temperature for a period of at least 1 hour.

24. A method for producing a magnetoresistive magnetic field sensor (10) according to claim 19, comprising the steps of producing the arrangement of a layer structure (100) according to the method of claim 20 and at least temporarily applying at least one of the soft magnetic patterned elements (18), wherein The pretreatment magnetic field Hz (38) is injected into the layer structure (100) with different magnetization directions as a pinning field M0 (60) via the soft magnetic patterned element (18).

25. Method for producing a magnetoresistive magnetic field sensor (10) according to claim 24, the soft magnetic patterned element (18) then being removed again after the pinning has been terminated.

26. The method according to claim 24, wherein: An arrangement of at least two adjacent mutually spaced layer structures (100) is applied to the substrate (110), and the soft magnetic patterned element (18) is at least temporarily applied between the layer structures (100), and wherein the pretreatment magnetic field Hz (38) is injected into the soft magnetic patterned element (18) perpendicularly to the surface of the substrate (110), so that the stray magnetic field generated by the soft magnetic patterned element (18) provides different orientations of the pinning fields M0 (60) of adjacent layer structures (100) as a pinning field M0 (60) substantially parallel to the surface of the substrate (110), and the orientations of the pinning fields M0 (60) of the adjacent layer structures (100) depend on the side geometry of the soft magnetic patterned element (18), so that the orientations of the pinning fields M0 (60) of the adjacent layer structures (100) are different from each other.

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