Magnetic field sensor for detecting two-dimensional external magnetic field with low anisotropy

Abstract

a magnetic tunnel junction (2) comprising a reference layer (23) having a fixed reference magnetization (230), a sense ferromagnetic layer (21) having a sense magnetization (210), and a tunnel barrier layer (22) between the sense ferromagnetic layer (21) and the reference ferromagnetic layer (23); The sense ferromagnetic layer (21) a first sense ferromagnetic layer (211) in contact with the tunnel barrier layer (22); a second sense ferromagnetic layer (212); A magnetic field sensor for detecting a two-dimensional external magnetic field, comprising a first non-magnetic layer (213) between a first sense ferromagnetic layer (211) and a second sense ferromagnetic layer (212), The second sense ferromagnetic layer (212) comprises a plurality of multi-layer elements (216), each of which comprises a second non-magnetic layer (215) between two second ferromagnetic sense layers (214); The magnetic field sensor for detecting a two-dimensional external magnetic field is characterized in that the second sense ferromagnetic layer (212) has a thickness of 20 nm or less.

Description

[Technical field]

[0001] The present invention relates to a tunneling magnetoresistance device and a magnetic field sensor using the tunneling magnetoresistance effect, more particularly to a magnetic field sensor for sensing a two-dimensional external magnetic field having a low magnetic anisotropy field. [Background technology]

[0002] A self-referencing magnetic tunnel junction may be used to sense a magnetic field in a magnetic sensor or compass. A self-referencing magnetic tunnel junction typically comprises a reference layer having a reference magnetization, a sense layer having a sense magnetization, and a tunnel barrier layer between the sense layer and the reference layer. During a sensing operation, an external magnetic field aligns the sense magnetization more parallel or more anti-parallel to the reference magnetization.

[0003] In two-dimensional magnetic sensing, the sense layer typically has a magnetization that is fixed in magnitude and rotates in a plane parallel to the direction of magnetization in the reference layer. Typically, the sense layer has a preferred orientation of magnetization in this plane. This is the lowest energy orientation. The magnetic field H k is called the magnetic anisotropy of the sense layer. The sensor signal depends on the relative orientation of the sense and reference layers, and the angular accuracy (low angular error) depends on the anisotropy of the sense layer being as low as possible in this plane. This minimizes the energy difference between the various planar orientations of the sense layer, resulting in a sensor output that closely reflects the external magnetic field direction, resulting in a low angular error of the sensor.

[0004] In practice, however, the sense layer has a finite magnetic anisotropy. The sense magnetization can be subject to a finite stray field from the reference layer. This causes angular errors in the alignment of the sense magnetization in the external magnetic field, and therefore in the expected resistance of the magnetic sensor element for a given direction of the external magnetic field. These angular errors limit the operating margin of the sensor at low external magnetic field magnitudes, since the angular errors increase as the magnitude of the external magnetic field is reduced.

[0005] The accuracy of angular sensing can therefore be improved by reducing the magnetic anisotropy of the sense layer, which can be reduced by increasing the thickness of the sense layer, however, increasing the thickness of the sense layer can result in non-uniform magnetization in the plane of the sense layer, degrading performance and increasing the minimum usable magnetic field of the magnetic sensor.

[0006] Patent Document 1 (US2014242418) discloses a magnetoresistance element comprising a free ferromagnetic layer, a pinned ferromagnetic layer, and a non-magnetic tunnel barrier layer. The free ferromagnetic layer comprises two magnetic sublayers separated from each other by a thin non-magnetic spacer sublayer. The free ferromagnetic layer has a magnetization direction oriented perpendicular to the film surface.

[0007] US6788502 describes a magnetic tunnel junction sensor having a laminated free layer with a first sublayer made of Co-Fe in contact with a spacer layer and a second sublayer made of Ni-Fe-Mo, where the Ni-Fe-Mo material of the second sublayer has a magnetocrystalline anisotropy constant that is much smaller than that of Ni-Fe.

[0008] Non-Patent Document 1 (Gonzalez-Guerrero et al., "Effect of Deposition-Induced Stress on the Magnetic Properties of Magnetostrictive Amorphous (Fe80Co20)80B20 Multilayer Films," Journal of Applied Physics 102, 123903 (2007) describes that control of the mechanical stress induced during deposition of sputtered amorphous magnetostrictive (Fe80Co20) allows custom design of its magnetic properties. FeCoB multilayer films are sputtered onto thermal oxide Si (silicon) substrates using different buffer materials. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] US Patent Application Publication No. 2014 / 242418 [Patent Document 2] U.S. Patent No. 6,788,502 [Non-patent literature]

[0010] [Non-Patent Document 1] Gonzalez-Guerrero et. al., “Influence of the deposition-induced stress on the magnetic properties of magnetostrictive amorphous(Fe80Co20)80B20 multilayers”, Journal of Applied Physics 102, 123903 (2007) Summary of the Invention [Problem to be solved by the invention]

[0011] The present disclosure relates to a magnetic field sensor for detecting an external magnetic field, the magnetic field sensor comprising: a reference layer having a fixed reference magnetization; a sense ferromagnetic layer having a sense magnetization; The present invention relates to a magnetic field sensor for sensing a two-dimensional external magnetic field, comprising a magnetic tunnel junction comprising a tunnel barrier layer between the sense ferromagnetic layer and the reference ferromagnetic layer. The sense ferromagnetic layer is a first sense ferromagnetic layer in contact with the tunnel barrier layer; A second sense ferromagnetic layer; a first non-magnetic layer between the first sense ferromagnetic layer and the second sense ferromagnetic layer; the second sense ferromagnetic layer comprises a plurality of multi-layer elements, each of which comprises a second non-magnetic layer between two second ferromagnetic sense layers; The second sense ferromagnetic layer has a thickness of less than 20 nm, preferably less than 12 nm. The second nonmagnetic layer contains a refractory metal. The first ferromagnetic layer and the second ferromagnetic layer are made of a ferromagnetic material that does not contain a refractory metal. [Means for solving the problem]

[0012] The present disclosure further relates to a method of manufacturing a magnetic field sensor, the method comprising: The method includes depositing a reference layer, a tunnel barrier layer, a first sense ferromagnetic layer, a first non-magnetic layer, and a second sense ferromagnetic layer. The step of depositing the second sense ferromagnetic layer comprises depositing a plurality of multi-layer elements, including, for each multi-layer element, sequentially depositing a second non-magnetic layer between two second ferromagnetic sense layers.

[0013] This magnetic field sensor allows for a reduction in the anisotropy field without further increasing the thickness of the sense layer.

[0014] The invention will be better understood with the help of the description of embodiments given by way of example and illustrated in the figures. [Brief description of the drawings]

[0015] [Figure 1] 2 shows a schematic diagram of a magnetic tunnel junction comprising a first sense layer and a second sense layer according to one embodiment. [Diagram 2] FIG. 2 shows a schematic diagram of a second sense ferromagnetic layer comprising a plurality of second non-magnetic layers sandwiched between second ferromagnetic sense layers. [Diagram 3] 4 is a graph showing the relationship between the anisotropy magnetic field and the thickness of the second nonmagnetic layer. [Figure 4] 4a to 4c report magnetic loops measured in the easy and hard axis directions of the sense layer. [Diagram 5] FIG. 5 shows the relationship between the anisotropy magnetic field and the number of second nonmagnetic layers. [Figure 6] FIG. 6 shows the relationship between the anisotropy field and the thickness of the second nonmagnetic layer. [Figure 7] FIG. 7 represents a top view of a magnetic tunnel junction showing different possible deposition angles. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] 1 shows a schematic diagram of a magnetic tunnel junction 2 according to one embodiment. The magnetic tunnel junction 2 comprises a reference layer 23, a sense ferromagnetic layer 21 and a tunnel barrier layer 22 between the sense ferromagnetic layers 21,23 and the reference ferromagnetic layers 21,23.

[0017] The reference layer 23 has a fixed reference magnetization 230, while the sense layer 21 has a sense magnetization 210 that is freely oriented with respect to the reference magnetization 230 in the presence of an external magnetic field. In other words, when the magnetic field sensor including the magnetic tunnel junction 2 is in the presence of an external magnetic field, the reference magnetization 230 remains substantially fixed and the sense magnetization 210 is deflected in the direction of the external magnetic field.

[0018] To that end, the magnetic sensor cell 1 comprises an antiferromagnetic layer 24, which adjusts the reference magnetization 230 to a low temperature threshold T L and the high temperature threshold T H The reference layer 23 is exchange-coupled, for example, by releasing the

[0019] Suitable materials for the antiferromagnetic layer 24 can include transition metals and their alloys. For example, suitable antiferromagnetic materials include manganese (Mn)-based alloys, such as alloys based on iridium (Ir) and Mn (e.g., IrMn), Fe and Mn-based alloys (e.g., FeMn), platinum (Pt) and Mn (e.g., PtMn)-based alloys, and Ni and Mn-based alloys (e.g., NiMn). In some cases, the high temperature threshold T of Ir and Mn-based (or Fe and Mn-based) alloys may be H is in the following range: about 120° C. to about 220° C., or about 150° C. to about 200° C., for example about 200° C.; and the high temperature threshold T H This may be within a range of about 300° C. to about 350° C. Suitable materials for the antiferromagnetic layer 24 may further include an oxide layer, such as NiO.

[0020] In one possible configuration, the antiferromagnetic layer 24 has a thickness of about 10 or 12 nm. Alternatively, the antiferromagnetic layer 24 may comprise multiple layers, each layer having a thickness between 1 and 2 nm.

[0021] The reference layer 23 may comprise one or more ferromagnetic layers (not shown), each containing Co, Fe, Ni, CoFeB or alloys thereof. The reference layer 23 may further comprise a synthetic antiferromagnet (SAF) comprising at least two ferromagnetic layers, the ferromagnetic layer furthest from the tunnel barrier layer 22 being separated by a non-magnetic layer pinned by the anti-ferromagnet, while the other ferromagnetic layers are coupled to the adjacent ferromagnetic layers through the non-magnetic layers separating them by a RKKY coupling mechanism. The non-magnetic layers may contain Ru, Ir or Cu or combinations thereof.

[0022] The tunnel barrier (layer) 22 may comprise or be formed from an insulating material. Suitable insulating materials include oxides such as aluminum oxide (e.g., AI2O3) and magnesium oxide (e.g., MgO). The thickness of the tunnel barrier layer 22 may be in the nanometer range, such as about 1 nm to about 3 nm. The optimal thickness of the tunnel barrier 22 may be obtained by inserting multiple (double or multiple) layers of MgO (or another suitable oxide or insulating material).

[0023] The sense ferromagnetic layer 21 includes a ferromagnetic layer 211 in contact with the tunnel barrier layer 22 , a second sense ferromagnetic layer 212 , and a first non-magnetic layer 213 between the first sense ferromagnetic layer 211 and the second sense ferromagnetic layer 212 .

[0024] 1, the sense magnetization 210 can be oriented in the plane of the sense layer 21 in the presence of an external magnetic field. In other words, the sense magnetization 210 remains magnetized in-plane.

[0025] The fixed (or pinned) reference magnetization 230 of the reference layer 23 is also in-plane, i.e. in the plane of the reference layer 23. If the magnetic sensor cell 1 comprises an antiferromagnetic layer 24, the antiferromagnetic layer 24 has a magnetization oriented in-plane (in the plane of the antiferromagnetic layer 24).

[0026] In one embodiment, the second sense ferromagnetic layer 212 includes a plurality of multi-layer elements 216 , each of which includes a second non-magnetic layer 215 between two second ferromagnetic sense layers 214 .

[0027] The purpose of the second non-magnetic layer 215 is to change the microstructure of the second sense ferromagnetic layer 212 to make it finer, or even amorphous. A finer or even amorphous structure of the second sense ferromagnetic layer 212 reduces the magnetic anisotropy of the sense layer 21 and therefore improves the low field angular error in the two-dimensional magnetic field sensor.

[0028] FIG. 2 shows a schematic diagram of a second sense ferromagnetic layer 212 comprising five multilayer elements 216, each comprising, in that order, a second non-magnetic layer 215 sandwiched between two second ferromagnetic sense layers 214.

[0029] In one embodiment, the structure of the sense layer 21 is as follows. CоFeB 1.5 Ta 0.3 / [NiFe2Ta x ]*5 / NiFe2(1) Here, the first sense ferromagnetic layer 211 comprises a 1.5 nm thick CoFeB alloy, the first non-magnetic layer 213 comprises a 0.3 nm thick Ta layer, the second ferromagnetic sense layer 214 comprises a 2 nm thick NiFe alloy and the second non-magnetic layer 215 comprises a Ta layer with a thickness x varying between 0.1 nm and 0.4 nm.

[0030] Figure 3 shows the anisotropy magnetic field H k 10 is a graph showing the relationship between the anisotropy magnetic field H k The following structure is shown: CoFeB without annealing 1.5 / Ta 0.3 / NiFe 12 FIG. 3 shows that the anisotropy field H k , which shows that the capacitance decreases with increasing annealing temperature. In some embodiments, the sense layer 21 may be annealed at an annealing temperature of greater than 240° C. For example, the sense layer 21 may be annealed at an annealing temperature of 310° C. for 90 minutes.

[0031] 4 reports the magnetic loops measured in the easy axis (0°) and hard axis (90°) directions for structure (1) of the sense layer 21. The sense layer 21 was not annealed. In particular, Fig. 4a and Fig. 4b show the magnetic loops for the second non-magnetic layer 215 having a thickness of 0.3 nm, and Fig. 4c shows the magnetic loops for the second non-magnetic layer 215 having a thickness of 0.5 nm. In Fig. 4a and Fig. 4c, the magnetic loops are measured in the easy axis and are measured under a coercive magnetic field H of about 2 Oe. cIn Figure 4b, the magnetic loop measured on the hard axis has an anisotropy field H of about 13 Oe. k For a second non-magnetic layer 215 with a thickness of 0.5 nm, antiferromagnetic coupling through the Ta second non-magnetic layer 215 is observed. To avoid such antiferromagnetic coupling, the thickness of the second non-magnetic layer 215 must be less than 0.5 nm. Thus, a thickness between 0.1 nm and 0.4 nm is advantageous. In one embodiment, the thickness of the second non-magnetic layer 215 is about 0.3 nm.

[0032] Figure 5 shows the anisotropy field H k and the number of second non-magnetic layers 215 in the second sense ferromagnetic layer 212. In particular, the anisotropy field H reported for the first sense ferromagnetic layer 211 made of a CoFeB alloy and the second non-magnetic layers 215 made of Ta or Mg is shown. k It has been reported that the first sense ferromagnetic layer 211 has a thickness of about 1.5 nm, and the second non-magnetic layer 215 has a thickness of about 0.2 nm or 0.4 nm. The second sense ferromagnetic layer 212 has a thickness of about 12 nm. The sense layer 21 is annealed at 310° C. for 90 minutes in the absence of a magnetic field. FIG. 5 shows that the anisotropy magnetic field H increases by increasing the number of second non-magnetic layers 215 when the second non-magnetic layers 215 are made of Ta. k This shows that it is possible to reduce

[0033] The number of layers, five, of the five second non-magnetic layers 215 for the sense layer 21 is the lowest anisotropy field H k , and therefore appears to be the most preferred configuration. The number of second non-magnetic layers 215 may exceed five. However, increasing the number of second non-magnetic layers 215 tends to reduce the sense magnetization 210.

[0034] Other materials can be used for the first sense ferromagnetic layer 211, the first non-magnetic layer 213, the second ferromagnetic sense layer 214 and the second non-magnetic layer 215, and other thicknesses of these layers are contemplated within the scope of the present invention. In general, the second non-magnetic layer 215 may have a thickness that varies between 0.1 nm and 0.4 nm. More specifically, the second non-magnetic layer 215 may have a thickness of about 0.1 nm, 0.2 nm, 0.3 nm, or 0.4 nm.

[0035] In one variation, the first sense ferromagnetic layer 211 has a multi-layer structure. For example, the first sense ferromagnetic layer 211 may have 2 to 5 ferromagnetic layers. The ferromagnetic layer 211 may contain CoFe, CoFeB, NiFe alloy or any other suitable ferromagnetic alloy.

[0036] For example, the second non-magnetic layer 215 may contain a refractory metal. More specifically, the second non-magnetic layer 215 may contain one of the following metals, Ta, Zr, W, Ti, Mo, Nb, Hf, either alone or in combination. The second ferromagnetic sense layer 210 may also be made of CoFe or CoFeB alloy. In general, the second ferromagnetic sense layer 210 may have a thickness between 1 nm and 3 nm, preferably between 1.1 nm and 3 nm, or between 1.5 nm and 5 nm. This ensures an in-plane magnetization direction, which is necessary for two-dimensional magnetic sensing of the magnetic field sensor.

[0037] Preferably, the second non-magnetic layer 215 comprises Ta. The second non-magnetic layer 215 made of (or containing) Ta reduces the in-plane anisotropy magnetic field H k This makes it possible to reduce

[0038] In one aspect, the first sense ferromagnetic layer 211 and the second ferromagnetic sense layer 214 are made of ferromagnetic materials that do not contain refractory metals. In particular, the sense ferromagnetic layer 211 and the second ferromagnetic sense layer 210 are made of ferromagnetic materials that do not contain any of Ti, V, Cr, Zr, Mn, Nb, Mo, Hf, Tc, Ru, Rh, Ta, W, Re, Os or Ir. In fact, the presence of such refractory metals in the first sense ferromagnetic layer 211 and / or the second ferromagnetic sense layer 214 promotes perpendicular magnetization of the first and second sense ferromagnetic layers 211, 214 instead of the in-plane magnetization direction required for two-dimensional magnetic sensing of the magnetic field sensor.

[0039] For example, the first sense ferromagnetic layer 211 and the second ferromagnetic sense layer 214 may be made of CoFe, CoFeB, NiFe based alloy or any other suitable ferromagnetic alloy (without refractory metals). Preferably, the first sense ferromagnetic layer 211 is made of a CoFeB based alloy and the second ferromagnetic sense layer 214 is made of a NiFe based alloy. In the latter configuration, the anisotropy field can be further reduced.

[0040] FIG. 6 shows the anisotropy magnetic field H k 1 shows the relationship between the value of θ and the thickness of the second non-magnetic layer 215. The second sense ferromagnetic layer 212 comprises five multilayer elements 216. The second non-magnetic layer 215 is made of W. The relationship is shown for a sense layer 21 that has been annealed at 260° C. in the absence of a magnetic field. The anneal may comprise a heating ramp of about 30 minutes, an annealing plateau (at 260° C.) of about 30 minutes, and a cooling ramp of about 30 minutes (so that the total time for the annealing step is about 90 minutes).

[0041] According to one embodiment, a method of manufacturing the magnetic tunnel junction 2 comprises depositing, using a deposition tool, a reference layer 23, a tunnel barrier layer 22, a first sense ferromagnetic layer 211, a first non-magnetic layer 213 and a second sense ferromagnetic layer 212 on a substrate (not shown). Depositing the second sense ferromagnetic layer 212 comprises depositing a plurality of multi-layer elements 216 including, for each multi-layer element, sequentially depositing a second non-magnetic layer 215 between two second ferromagnetic sense layers 214.

[0042] In a preferred embodiment, each multilayer element 216 is deposited at a deposition angle θ that is different from the deposition angle of the next multilayer element 212. The deposition angle θ may be determined relative to a reference angle on the substrate on which the multilayer element 216 is deposited. For example, such a reference angle may correspond to a notch on the wafer. The reference angle may determine the 0° direction used in the deposition tool. Figure 7 illustrates a top view of the magnetic tunnel junction 2 showing different possible deposition angles θ.

[0043] In one variation, multiple multi-layer elements 216 are successively deposited with the deposition angle θ varying to include 0° and 90°.

[0044] In another variation, multiple multi-layer elements 216 are successively deposited at deposition angles θ that vary to include 45° and 135°.

[0045] In yet another variation, multiple multi-layer elements 216 are successively deposited at deposition angles θ that vary, including 0°, 45°, 90°, and 135°.

[0046] The process of varying the deposition angle θ can also be used when depositing the other layers of the magnetic tunnel junction 2 , including the first sense ferromagnetic layer 211 , the tunnel barrier layer 22 and the reference layer 23 .

[0047] Varying the deposition angle θ when depositing the multi-layer element 216 allows for averaging and reduces the magnetic anisotropy of the sense layer 21. Any residual magnetic anisotropy that may remain can be further reduced by introducing a second non-magnetic layer 215.

[0048] In some embodiments, the deposition angle θ may be constant, or the deposition angle θ may be continuously varied, for example, by continuously rotating the substrate on which the magnetic tunnel junction layer is deposited.

[0049] In various embodiments, the structure of the sense layer 21 may be as follows. CoFeB0.5 / <0> / CoFeB0.5 / <90> / CoFeB0.5 / Ta0.3 / NiFe1 / <0> / NiFe1 / Ta0.3 / NiFe1 / <90> / NiFe1 / Ta0.3 / NiFe1 / <0> / NiFe1 / Ta0.3 / NiFe1 / <90> / NiFe1 / Ta0.3 / NiFe1 / <0> / NiFe1 / Ta0.3 / NiFe1 (2) CoFeB0.5 / <45> / CoFeB0.5 / <135> / CoFeB0.5 / Ta0.3 / NiFe1 / <45> / NiFe1 / Ta0.3 / NiFe1 / <135> / NiFe1 / Ta0.3 / NiFe1 / <45> / NiFe1 / Ta0.3 / NiFe1 / <135> / NiFe1 / Ta0.3 / NiFe1 / <45> / NiFe1 / Ta0.3 / NiFe1 (3) Here, the symbol <0> , <45> , <90> , and <135> corresponds to deposition angles θ of 0°, 90°, 45°, and 135°, respectively.

[0050] Other configurations of the sense layer 21 structure may be considered. The present application provides, for example, the following aspects: [Point 1] a reference layer (23) having a fixed reference magnetization (230) oriented in the plane of the reference layer (23); a sense ferromagnetic layer (21) having a sense magnetization (210) orientable in the plane of the sense ferromagnetic layer (21); a tunnel barrier layer (22) between the sense ferromagnetic layer (21) and the reference ferromagnetic layer (23); The magnetic tunnel junction (2) comprises: A sense ferromagnetic layer (21), a first sense ferromagnetic layer (211) in contact with the tunnel barrier layer (22); A second sense ferromagnetic layer (212); A magnetic field sensor for detecting a two-dimensional external magnetic field, comprising a first non-magnetic layer (213) between a first sense ferromagnetic layer (211) and a second sense ferromagnetic layer (212), The second sense ferromagnetic layer (212) comprises a plurality of multi-layer elements (216), each of which comprises a second non-magnetic layer (215) between two second ferromagnetic sense layers (214); The second sense ferromagnetic layer (212) has a thickness of 20 nm or less. A magnetic field sensor for detecting a two-dimensional external magnetic field. [Point 2] The magnetic field sensor according to aspect 1, wherein the second sense ferromagnetic layer (212) comprises a number of multi-layer elements (216) between 2 and 10 layers. [Point 3] The magnetic field sensor according to aspect 2, wherein the multi-layer configuration comprises five multi-layer elements (216). [Point 4] A magnetic field sensor according to any one of the preceding aspects, wherein the second ferromagnetic sense layer (214) comprises a NiFe alloy. [Point 5] A magnetic field sensor according to any one of the preceding aspects, wherein the first ferromagnetic sense layer (211) comprises a CoFeB alloy. [Point 6] A magnetic field sensor according to any one of the preceding aspects, wherein the second non-magnetic layer (215) contains a high melting point material. [Point 7] 7. The magnetic field sensor of claim 6, wherein the second non-magnetic layer (215) contains one or a combination of the following metals: Ta, Zr, W, Ti, Mo, Nb, Hf. [Point 8] A magnetic field sensor according to any one of the preceding aspects, wherein the second non-magnetic layer (215) has a thickness of between 0.1 nm and 0.4 nm. [Point 9] The magnetic field sensor of aspect 8, wherein the second non-magnetic layer has a thickness of about 0.2 nm, about 0.3 nm, or about 0.4 nm. [Point 10] A magnetic field sensor according to any one of the preceding aspects, wherein the second ferromagnetic sense layer (214) has a thickness between 1 nm and 3 nm, preferably between 1.1 nm and 3 nm, or between 1.5 nm and 5 nm. [Point 11] A method for manufacturing a magnetic field sensor according to any one of the first to tenth aspects, comprising depositing a reference layer (23), a tunnel barrier layer (22), a first sense ferromagnetic layer (211), a first non-magnetic layer (213) and a second sense ferromagnetic layer (212), The step of depositing the second sense ferromagnetic layer (212) comprises: The method comprises depositing a plurality of multi-layer elements (216), each of the multi-layer elements including successively depositing a second non-magnetic layer (215) between two second non-magnetic layers (214). [Point 12] Each multi-layer element (216) is deposited on the substrate at a deposition angle (θ) different from the deposition angle of the next multi-layer element (216); The method for manufacturing a magnetic field sensor according to aspect 11, wherein the deposition angle is determined relative to a reference angle on the substrate at which the multi-layer element (216) is deposited. [Point 13] A method for manufacturing a magnetic field sensor according to aspect 12, wherein the multiple multi-layer elements (216) are successively deposited at varying deposition angles (θ) between 0° and 90°. [Point 14] 14. A method for producing a magnetic field sensor according to any one of aspects 11 to 13, further comprising an annealing step at above 240° C. [Point 15] 15. The method of claim 14, wherein the annealing step is carried out at about 310° C. for about 90 minutes. [Point 16] 16. The magnetic field sensor according to any one of the preceding aspects, wherein the second non-magnetic layer (215) comprises one of Ta. [Point 17] 18. The magnetic field sensor according to any one of the preceding aspects, wherein the first sense ferromagnetic layer (211) and the second sense ferromagnetic layer (214) do not contain a ferromagnetic material of a high melting point metal. [Point 18] A method for manufacturing a magnetic field sensor according to aspect 18, wherein the second ferromagnetic sense layer (214) contains a NiFe alloy and the first ferromagnetic sense layer (211) contains a CoFeB alloy. [Explanation of symbols]

[0051] 2. Magnetic tunnel junction 21 Sensation Layer 210 Detecting magnetization 211 First sense ferromagnetic layer 212 Second sense ferromagnetic layer 213 First nonmagnetic layer 214 Second ferromagnetic sense layer 215 Second nonmagnetic layer 216 Compound Elements 22 Tunnel Barrier Layer 23 Reference layer 230 Reference magnetization 231 Ferromagnetic reference layer 232 Non-magnetic reference layer 24 Fixed layer θ Deposition angle Hc forced magnetic field H k Anisotropic magnetic field

Claims

1. a reference layer having a fixed reference magnetization oriented in the plane of the reference layer; a sense layer having a sense magnetization orientable in the plane of the sense layer; a tunnel barrier layer between the sense layer and the reference layer; A magnetic tunnel junction comprising: The sense layer comprises: a first sense ferromagnetic layer in contact with the tunnel barrier layer; A second sense ferromagnetic layer; a first non-magnetic layer between the first sense ferromagnetic layer and the second sense ferromagnetic layer, the second sense ferromagnetic layer comprises a plurality of multi-layer elements, each of which comprises a second non-magnetic layer between two second ferromagnetic sense layers; the second sense ferromagnetic layer has a thickness of 12 nm; the first sense ferromagnetic layer and the second ferromagnetic sense layer are made of a ferromagnetic material that does not contain any of Ti, V, Cr, Zr, Mn, Nb, Mo, Hf, Tc, Ru, Rh, Ta, W, Re, Os, or Ir; A method for manufacturing a magnetic field sensor, comprising the steps of:

1. A method for manufacturing a magnetic field sensor, comprising depositing the reference layer, the tunnel barrier layer, the first sense ferromagnetic layer, the first non-magnetic layer, and the second sense ferromagnetic layer, depositing the second sense ferromagnetic layer, depositing a plurality of multi-layer elements, each of the multi-layer elements including sequentially depositing a second non-magnetic layer between two second ferromagnetic sense layers; each multilayer element is deposited on the substrate at a deposition angle (θ) different from the deposition angle of adjacent multilayer elements; the deposition angle is determined relative to a reference angle on the substrate onto which the multi-layer element is deposited; The manufacturing method.

2. The method of claim 1 , wherein the plurality of multi-layer elements are deposited sequentially while varying the deposition angle between 0° and 90°.

3. The method for manufacturing a magnetic field sensor as claimed in claim 1, further comprising an annealing step with an annealing plateau at 260°C or 310°C and a total time of the annealing step of 90 minutes.

4. 2. The method of claim 1, wherein the second ferromagnetic sense layer comprises a NiFe alloy and the first sense ferromagnetic layer comprises a CoFeB alloy.

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