TWI513071B - Magnetoresistance film structure and the magnetic field sensor using the magnetoresistance film structure - Google Patents

Description

Magnetoresistive film layer structure and magnetic field sensor application using the magnetoresistive film layer structure

The present invention relates to a film layer structure. More specifically, it relates to a magnetoresistive film structure, which can be applied to technical fields such as magnetic field sensing.

It is known that the magnetoresistance (MR) effect is the effect of the resistance of a material changing with an applied magnetic field. The definition of the physical quantity is the difference in resistance between the presence or absence of a magnetic field, and the original resistance is used to represent the rate of change of resistance. .

The giant magnetoresistance (GMR) effect exists in a multilayer film system of ferromagnetic (eg, Fe, Co, Ni)/non-ferromagnetic (eg, Cr, Cu, Ag, Au) due to magnetic exchange between magnetic layers. The effect changes its conduction electron behavior, causing the magnetic scattering of different degrees of electron generation to cause a large resistance, and its resistance change is much larger than the ordinary magnetic resistance, so it is called "giant magnetoresistance". The resistance value of the multilayer film structure is related to the magnetization direction of the ferromagnetic material film layer, and the resistance value of the two layers of magnetic material in the opposite direction of magnetization is significantly larger than the resistance value when the magnetization direction is the same, and the resistance is in a weak applied magnetic field. There is a big amount of change underneath. The tunnel magnetoresistance (TMR) effect refers to the effect of the tunneling resistance on the relative orientation of the ferromagnetic materials in the ferromagnetic/insulator film (about 1 nm)/ferromagnetic material.

At present, the magnetoresistance effect has been successfully applied to hard disk production and has important commercial application value. In addition, magnetic giant random access memory (MRAM) can also be fabricated by using giant magnetoresistance materials having different resistance values under different magnetization states, and the advantage is that the stored data can be retained without power supply.

The above magnetoresistance effect is also applied in the field of magnetic field sensors, for example For example, a mobile phone with a global positioning system (GPS) electronic compass component is used to provide information such as the user's mobile position. At present, various magnetic field sensing technologies have been available on the market, for example, anisotropic magnetoresistance (AMR) sensing elements, giant magnetoresistance (GMR) sensing elements, and magnetic tunneling junctions. , MTJ) sensing elements and the like.

However, the disadvantages of the prior art described above generally include: the area of the wafer is relatively large, and the process is relatively high. Expensive, more power-hungry, insufficient sensitivity, and susceptible to temperature changes, etc., and further improvements are necessary.

The present invention proposes an innovative magnetoresistive film junction that can be applied to a magnetic field sensor. To address the deficiencies and shortcomings of the prior art described above.

According to an aspect of the present invention, a magnetoresistive film layer structure including a fixed a layer, a fixed layer is disposed on the fixed layer, an orthogonal coupling layer is disposed on the fixed layer, a reference layer is disposed on the orthogonal coupling layer, and a spacer layer is disposed on the reference layer Upper and a free layer are disposed on the spacer layer.

According to another aspect of the present invention, a biaxial magnetic field sensor is provided, which comprises a substrate, at least one first sensing cell having the film layer structure disposed on a substrate plane for sensing a first axial magnetic field change; and at least one second sensing cell having the film layer structure And being disposed on a plane of the substrate for sensing a second axial magnetic field change, wherein the first sensing cell and the second sensing cell have a long axis and a short axis, and the long axis of the first sensing cell The direction is perpendicular to the long axis direction of the second sensing cell.

According to still another aspect of the present invention, a three-axis magnetic field sensor is provided, which comprises a substrate, at least one first sensing cell having the film layer structure disposed on a substrate plane for sensing a first axial magnetic field change; at least one second sensing cell having the film layer structure Sensing a second axial magnetic field change on the substrate plane, and at least one having the film layer structure The three sensing cells are disposed on a slope of the substrate for sensing a third axial magnetic field change, wherein the first sensing cell, the second sensing cell, and the third sensing cell both have a long axis and a short axis And the long axis direction of the first sensing cell, the long axis direction of the second sensing cell, and the long axis direction of the third sensing cell are perpendicular to each other.

The above described objects, features and advantages of the present invention will become more apparent from the description of the appended claims. However, the following preferred embodiments and drawings are for illustrative purposes only and are not intended to limit the invention.

1/1a/1b/1c‧‧‧ sensory cells

10‧‧‧Fixed layer

12‧‧‧ fixed layer

14‧‧‧Orthogonal coupling layer

16‧‧‧ reference layer

18‧‧‧ spacer

20‧‧‧Free layer

60‧‧‧ field annealing process

62~66‧‧‧Steps

80‧‧‧Magnetoresistive film layer cell

82‧‧‧Free layer magnetization direction

90‧‧‧External magnetic field direction

91/91a/91b‧‧‧Exchange bias coupling direction

92/92’/92”‧‧‧Magnetization direction of the reference layer

100‧‧‧Substrate

102‧‧‧Adhesive layer

104‧‧‧ seed layer

110‧‧‧Fixed layer

112‧‧‧ fixed layer

114‧‧‧Orthogonal coupling layer

116‧‧‧ reference layer

118‧‧‧ spacer

120‧‧‧Free layer

122‧‧‧Upper cover

160‧‧ ‧ field annealing process

162~164‧‧‧Steps

204‧‧‧ seed layer

214‧‧‧Orthogonal coupling layer

260‧‧ ‧ annealing process

262~265‧‧‧Steps

312‧‧‧ fixed layer

313/315‧‧‧Cobalt metal layer

316‧‧‧ reference layer

360‧‧‧ field annealing process

362~365‧‧‧Steps

400‧‧‧Substrate

402‧‧‧Protruding

402a‧‧‧Bevel

410/420/430‧‧‧Sensor unit

411~414‧‧‧Sense cells

421~424‧‧‧Sense cells

431~434‧‧‧Sense cells

500‧‧‧Substrate

510/520/530‧‧‧Sensor unit

511~514‧‧‧Sense cells

521~524‧‧‧Sense cells

531~534‧‧‧Sense cells

L‧‧‧ length

W‧‧‧Width

H‧‧‧ Height

x‧‧‧X-axis component

z‧‧‧Z-axis component

FIG. 1 is a side view showing a film structure of an X-axis sensing cell in a magnetic field sensor element according to an embodiment of the invention.

Fig. 2 is an exploded view of the film structure of the axial sensing cell and the direction of the magnetic moment in Fig. 1.

FIG. 3 is a side view of a film structure of a sensing cell according to another embodiment of the present invention.

4 is a side view of a film structure of a sensing cell according to still another embodiment of the present invention.

FIG. 5 is a side view of a film structure of a sensing cell according to still another embodiment of the present invention.

Figure 6 is a flow chart illustrating a field annealing process.

Fig. 7 is a top view showing a cuboid magnetoresistive film layer having long and short axes, showing an external magnetic field and a magnetization direction of the film.

Figure 8 illustrates another field annealing process.

Figure 9 illustrates another field annealing process.

Figure 10 illustrates yet another field annealing process.

11A and 11B respectively illustrate a side view and a top view of a sense cell layout of a triaxial magnetic field sensor element in accordance with an embodiment of the present invention.

12A and 12B are respectively side elevational and top views, respectively, illustrating a sense cell layout of a triaxial magnetic field sensor element in accordance with another embodiment of the present invention.

Fig. 13 is an enlarged schematic view of Figs. 11A and 11B.

The details of the present invention will be described hereinafter with reference to the accompanying drawings, and the contents of the drawings also constitute The detailed description of the specification is part of the description and is described in the manner of the specific examples of the exemplary embodiments. The following examples have been described in sufficient detail to enable those of ordinary skill in the art to practice. It is a matter of course that the invention can be practiced with other embodiments, or any structural, logical, or electrical changes can be made without departing from the embodiments described herein. Therefore, the following detailed description is not to be considered as a limitation, and the embodiments included herein are defined by the scope of the accompanying claims. In addition, the "magnetization direction" or "direction of magnetization" of a material layer or structure referred to hereinafter refers to the main dominance of the layer or the magnetic domain of the structure ( Magnetization direction. The term "layer" as used herein refers to a single layer of a single material or composition that does not include other materials or other layers unless otherwise specified.

Sense of cell membrane structure

Please refer to FIG. 1 and FIG. 2 , wherein FIG. 1 is a diagram of an embodiment of the present invention. A side view of the film structure of the sensor cell in the magnetic field sensor element, and FIG. 2 is an exploded view of the film structure of the sensing cell in FIG. 1 and the direction of the magnetic moment, wherein the sensing cell It can be an X-axis sensing cell. As shown in FIGS. 1 and 2, the film structure of the sensing cell 1 of the present invention is preferably a three-dimensional film structure having long and short axes, such as a rectangular parallelepiped. The magnetoresistive film layer structure 1 includes at least one pinning layer 10, a pinned layer 12, a biquadratic coupling layer 14, a reference layer 16, and a spacer. A spacer layer 18 and a free layer 20 are sequentially stacked. Of course, the structure of the magneto-resistive film layer of the rectangular parallelepiped in the figure is merely an illustration. In other embodiments, the magnetoresistive film layer structure can be patterned into other patterns having long and short axes, including rectangular, elliptical, diamond, oval, olive or eye shapes, and the like, when viewed from above. Therefore, the magnetoresistive film layer structure may be a rectangular parallelepiped shape, an elliptical cylinder, a rhombic cylinder, an oval cylinder, an olive cylinder or an eye cylinder.

According to an embodiment of the present invention, the fixed layer 12 is directly formed on the fixed layer 10 and is in direct contact with the fixed layer 10. The orthogonal coupling layer 14 is directly formed on the fixed layer 12, and is The fixed layer 12 is in direct contact. The reference layer 16 is formed directly on the orthogonal coupling layer 14 and is in direct contact with the orthogonal coupling layer 14. The spacer layer 18 is formed directly on the reference layer 16 and is in direct contact with the reference layer 16. The free layer 20 is formed directly on the spacer layer 18 and is in direct contact with the spacer layer 18. In order to avoid oxidation, an upper cover protective layer (not shown), such as a tantalum (Ta) layer, may be additionally provided on the free layer 20, but is not limited thereto. Further, the pinned layer 10 may be formed on a substrate (not shown) such as a tantalum oxide substrate or a hafnium oxide substrate.

According to an embodiment of the present invention, the above fixed layer 10 may be composed of an antiferromagnetic (AFM) material such as iron manganese (FeMn), platinum manganese (PtMn), lanthanum manganese (IrMn), and nickel oxide (NiO). And so on, to fix or limit the direction of the magnetic moment of the adjacent layer. The fixed layer 12 may be made of a ferromagnetic (FM) material such as iron, cobalt, nickel or an alloy thereof, and its magnetization direction is "fixed" by the fixed layer 10. The orthogonal coupling layer 14 may be an insulating layer, for example, composed of an oxide, for example, nickel iron oxide (NiFeO _x ), iron oxide (FeO _x ), nickel oxide (NiO), cobalt iron oxide (CoFe _{2 ).} O ₄ ), an oxide such as magnesium oxide (MgO). According to an embodiment of the invention, the orthogonal coupling layer 14 may be formed by sputtering to form a nickel iron layer, and then oxidizing the nickel iron layer into a nickel oxide layer by oxygen plasma to form a nano oxide layer (NOL). ). It should be noted that in addition to the oxide, the orthogonal coupling layer 14 may be formed using other materials such as nitrides, borides or fluorides.

According to an embodiment of the present invention, the reference layer 16 may be composed of a ferromagnetic material, for example For example, iron, cobalt, nickel or an alloy thereof may have the same composition as the fixed layer 12, but is not limited thereto. The spacer layer 18 may be composed of a non-ferromagnetic material such as copper, but is not limited thereto. In other embodiments, the spacer layer 18 can be selected from the group consisting of a metal, an oxide, or a nitride, wherein the oxide can be aluminum oxide or magnesium oxide, etc., and the nitride can be aluminum nitride or the like. The free layer 20 may be composed of a ferromagnetic material such as iron, cobalt, nickel or an alloy thereof, but is not limited thereto. Among them, the magnetization direction of the free layer 20 is "freely" changed by the external magnetic field.

a rectangular parallelepiped magnetoresistive film layer structure 1 illustrated in FIG. 1 having a length L, Width W and height H, where height H is the sum of the thicknesses of the individual layers. Each of the above layers 10 to 20 has Substantially the same length L × width W of the plane size. The above layers 10-20 can be formed by various sputtering methods, vapor deposition methods, molecular beam epitaxy methods or pulsed laser deposition methods, and after annealing and cooling treatment by an external magnetic field, finally etching by lithography and etching process. A rectangular parallelepiped magnetoresistive film layer structure as shown in Fig. 1 is obtained. One of the features of the present invention is that the fixed layer 10, the fixed layer 12, the orthogonal coupling layer 14, the reference layer 16, the spacer layer 18, and the free layer 20 are patterned by a single mask and a single etching step, that is, forming the first The rectangular parallelepiped film structure in Fig. 1, that is, the layers 10-20 of the film layer structure in Fig. 1 have substantially the same planar size (L × W), and only the difference in thickness, so that the process is For the purpose of simplification.

As shown in FIG. 2, the length L and the width W of the film structure of the sensing cell 1 of the present invention are as shown in FIG. The height H may correspond to the reference coordinate Y-axis, X-axis, and Z-axis directions, respectively. According to an embodiment of the present invention, the magnetization direction of the pinned layer 12 (as indicated by the arrow) may be set parallel to the Y-axis direction (but may be other directions), and the magnetization direction of the reference layer 16 (as indicated by the arrow) The coupling effect by the orthogonal coupling layer 14 is set to be parallel to the X-axis direction. In other words, the magnetization direction of the pinned layer 12 and the magnetization direction of the reference layer 16 are perpendicular to each other. In this example, the easy magnetization axis of the free layer 20 is parallel to the length direction thereof, so that the magnetization direction thereof is parallel to the Y-axis direction, and the magnetization direction of the reference layer 16 in the film structure of the sensing cell 1 of the present invention is It is set perpendicular to the length direction of the layer, that is, parallel to the width direction, which is one of the main features of the present invention.

Example one

Please refer to FIG. 3 , which is a film for sensing cells according to another embodiment of the invention. A side view of the layer structure. As shown in FIG. 3, the sensing cell 1a may be a rectangular parallelepiped structure or a three-dimensional film layer structure having long and short axes, and includes a substrate 100, an adhesive layer 102, a seed layer 104, and a bottom from top to bottom. The fixed layer 110, a fixed layer 112, an orthogonal coupling layer 114, a reference layer 116, a spacer layer 118, a free layer 120, and an upper cover protective layer 122. According to an embodiment of the invention, the substrate 100 may be a ceria substrate, the adhesive layer 102 may be a bismuth metal layer having a thickness of about 3.5 nm, and the seed layer 104 may be a copper metal layer having a thickness of about 2 nm.

Layers 110-120 in Figure 3 are similar to those described in Figures 1 and 2. According to an embodiment of the invention, the pinned layer 110 may be germanium manganese having a thickness of about 8 nm, the pinned layer 112 may be Co ₉₀ Fe _{10 having} a thickness of about 1 nm, and the orthogonal coupling layer 114 may be NiFeO _{x having} a thickness of about 2 nm. The reference layer 116 may be Co ₉₀ Fe _{10 having} a thickness of about 2.5 nm, the spacer layer 118 may be a copper metal layer having a thickness of about 3 nm, the free layer 120 may be Ni ₈₀ Fe ₂₀ having a thickness of about 5 nm, and the upper cap protective layer 122 may be a thickness. A layer of ruthenium metal of about 3.5 nm.

Example two

Please refer to FIG. 4 , which is a side view of a film structure of a sensing cell according to still another embodiment of the present invention. As shown in FIG. 4, the sensing cell 1b may be a rectangular parallelepiped structure or a three-dimensional film layer structure having long and short axes, and includes a substrate 100, an adhesive layer 102, a seed layer 204, and a bottom from top to bottom. The fixed layer 110, a fixed layer 112, an orthogonal coupling layer 214, a reference layer 116, a spacer layer 118, a free layer 120, and an upper cover protective layer 122. According to the embodiment of the present invention, the substrate 100 may also be a ceria substrate, the adhesive layer 102 may be a bismuth metal layer having a thickness of about 3.5 nm, and the pinned layer 110 may also be yttrium manganese having a thickness of about 8 nm, and the pinned layer 112 may be a thickness of about 1nm Co ₉₀ Fe _10, the reference layer 116 may be a thickness of about 2.5nm of Co ₉₀ Fe _10, the spacer layer 118 may be a copper metal layer of about 3nm thickness of the free layer 120 may be a thickness of about 5nm Ni ₈₀ The Fe ₂₀ and the upper cap protective layer 122 may be a base metal layer having a thickness of about 3.5 nm.

The difference between the sensing cell 1b in FIG. 4 and the sensing cell 1a in FIG. 3 is that the orthogonal coupling layer 214 of the sensing cell 1b in FIG. 4 is iron oxide (FeO _x ) having a thickness of about 2 nm. The seed layer 204 is a platinum metal layer having a thickness of about 2 nm. Applicants have discovered that the use of the FeO _x orthogonal coupling layer 214 in combination with the platinum seed layer 204 allows the sensing cell 1b to have better temperature resistance characteristics.

Similarly, the structure of the rectangular parallelepiped magnetoresistive film layer in FIGS. 3 and 4 is merely an illustration. In other embodiments, the magnetoresistive film layer structure can also be patterned into other patterns having long and short axes, including rectangles, ellipses, diamonds, ovals, olives, or eye shapes when viewed from the top down. )and many more.

Example three

Please refer to FIG. 5 , which is a side view of a film structure of a sensing cell according to still another embodiment of the present invention. As shown in FIG. 5, the sensing cell 1c may be a rectangular parallelepiped structure or a three-dimensional film layer structure having long and short axes, and includes a substrate 100, an adhesive layer 102, a seed layer 204, and a bottom from top to bottom. The fixed layer 110, a fixed layer 312, a cobalt metal layer 313, an orthogonal coupling layer 214, a cobalt metal layer 315, a reference layer 316, a spacer layer 118, a free layer 120, and an upper capping layer 122 . According to the embodiment of the present invention, the substrate 100 may also be a ceria substrate, the adhesive layer 102 may be a bismuth metal layer having a thickness of about 3.5 nm, and the pinned layer 110 may also be yttrium manganese having a thickness of about 8 nm, and the pinned layer 312 may be a thickness of about 1nm Ni ₈₀ Fe _20, the reference layer 316 may be approximately 2.5nm thickness of Ni ₈₀ Fe _20, the spacer layer 118 may be a copper metal layer of a thickness of approximately 3nm, the free layer 120 may be of a thickness of about 5nm Ni ₈₀ The Fe ₂₀ and the upper cap protective layer 122 may be a base metal layer having a thickness of about 3.5 nm.

The difference between the sensing cell 1c in FIG. 5 and the sensing cell 1b in FIG. 4 is: in the first 5, the sensing cell 1c, the orthogonal coupling layer 214 and the fixed layer 312, and the orthogonal coupling layer 214 and the reference layer 316 are respectively provided with cobalt metal layers 313, 315, the thickness of which may be 0.5 nm. To further enhance the temperature resistance.

In other embodiments, the cobalt metal layer 313 is between the fixed layer 312 or the cobalt metal. A Ruthenium metal layer may be additionally disposed between the layer 315 and the reference layer 316, which has the effect of reducing the demagnetizing magnetic field outside the structure of the magnetoresistive film layer, so that the exposed magnetic field of the reference layer 316 and the fixed layer 312 does not affect the freedom. The magnetization direction of the layer. Furthermore, the cobalt metal layers 313 and 315 may be directly replaced by a ferromagnetic material layer and a bismuth metal layer without providing the cobalt metal layers 313 and 315, or a ferromagnetic material layer may be additionally provided on the cobalt metal layer. The base metal layer is also designed to provide better magnetic field induction.

Similarly, the structure of the rectangular parallelepiped magnetoresistive film layer in Fig. 5 is merely an illustration. In other real In the embodiment, when viewed from the top, the structure of the magnetoresistive film layer can also be patterned into other patterns having long and short axes, including rectangular, elliptical, diamond, oval, olive or eye shapes.

Field annealing method

Figure 6 is a flow chart illustrating a field annealing process 60. First, step 62, An external magnetic field is applied to the rectangular parallelepiped magnetoresistive film layer structure 1 in Fig. 1 at room temperature. Next, in step 63, the temperature is raised to the blocking temperature so that the antiferromagnetic layer is temporarily unable to fix the magnetization direction of the adjacent ferromagnetic layer. Then, in step 64, the high temperature annealing is continued in the presence of an external magnetic field. At step 65, the temperature is then lowered to room temperature. Finally, in step 66, the external magnetic field is removed. Through the above annealing process, the exchange bias and the orthogonal coupling direction of the orthogonal coupling layer 14 can be arbitrarily controlled.

As shown in Fig. 7, a rectangular parallelepiped magnetoresistive film layer having long and short axes is illustrated. A top view of 80 (the film structure is the same as that shown in Fig. 1), the magnetization direction 92 of the reference layer is perpendicular to the direction of the external magnetic field 90 during annealing, and has an angle θ with the magnetization direction 82 of the free layer. The angle θ may be any angle between 0 and 180 degrees, which is determined by the direction of the external magnetic field during the field annealing process. Preferably, the angle θ may be an integer multiple of 45 degrees, such as 45 degrees, 90 degrees, 135 degrees, and the like. The direction of the external magnetic field is not parallel to the longitudinal direction of the film structure of the sensing cell, so it can also be called "off-axis setting".

FIG. 8 illustrates another field annealing process 160. First, in step 162, the temperature rises to the resistance. But the temperature. In step 163, high temperature annealing is performed and a brief pulsed external magnetic field is applied during the high temperature annealing. At step 164, the temperature is lowered to room temperature.

FIG. 9 illustrates another field annealing process 260. First, step 262, at room temperature, An external magnetic field is applied to the magnetoresistive film layer structure. In step 263, the temperature is raised to the blocking temperature, so that the antiferromagnetic layer is temporarily unable to fix the magnetization direction of the adjacent ferromagnetic layer. In step 264, the external magnetic field is then removed and the high temperature anneal is performed. At step 265, the temperature is lowered to room temperature.

FIG. 10 illustrates yet another field annealing process 360. First, step 362, at room temperature Next, an external magnetic field is applied to the structure of the magnetoresistive film layer. In step 363, the external magnetic field is removed and the temperature is raised to the blocking temperature, so that the antiferromagnetic layer is temporarily unable to fix the magnetization direction of the adjacent ferromagnetic layer. In step 364, high temperature annealing is performed. At step 365, the temperature is lowered to room temperature.

Two-axis and three-axis magnetic field sensors

The sensing cell layer structure of the present invention described above can be used to fabricate magnetic field sensing elements, Two different embodiments will be enumerated to explain in detail two different sensing cell arrangements of the biaxial and triaxial magnetic field sensing elements of the present invention and the direction of magnetization of the reference layer, the free layer, and the direction of the external magnetic field and the exchange bias. Relative relationship:

Example one

11A and 11B are respectively side views showing a magnetic field sensor according to an embodiment of the present invention and a corresponding top view thereof. As shown in FIG. 11A, the magnetic field sensor component of the present invention includes at least three sensing cells, which are respectively paired sensing cells 411 to 414, sensing cells 421 to 424, and sensing cells 431 to 434. The sensing cells 411~414 are used to sense the X-axis magnetic field, the sensing cells 421~424 are used to sense the Y-axis magnetic field, and the sensing cells 431-434 are used to sense the Z-axis magnetic field, three-axis. The directions are perpendicular to each other, achieving a three-dimensional magnetic field sensing. In this embodiment, the sensing cells 411-414 and the sensing cells 421-424 are all disposed on the plane of the substrate 400 for sensing the change of the magnetic field of the two axes (such as the X-axis and the Y-axis) on the plane of the substrate. The short-axis direction cross sections of the sensing cells 411 to 414 and the long-axis direction cross sections of the sensing cells 421 to 424 are respectively shown, and the sensing cells 431 to 434 are disposed on both sides of the inclined surface of the protrusion 402 on the substrate 400. It can sense the magnetic field component of the Z-axis, and the short-axis cross section of the sensing cells 431-434 is shown in the figure. The membrane structures of the sensing cells 411 to 414, the sensing cells 421 to 424, and the sensing cells 431 to 434 can all be designed as shown in FIG. 2, and the composition and material of the film layer will not be further described herein. For the present invention, the sensing cells 411 to 414, the sensing cells 421 to 424, and the sensing cells 431 to 434 for sensing different axial directions may have the same film structure, the difference being only because of the sensing cells. The magnetic field to be sensed is axially different, but has a different orientation configuration or an angle between different reference layers and the magnetization direction of the free layer.

Next, please refer to FIG. 11B, which depicts a top view of the sensing cell layout of the above magnetic field sensor. For convenience of explanation, the external magnetic field direction 90 and the exchange bias coupling direction 91a, 91b during field annealing are also shown in the figure. It should be noted that the sensing cells in this embodiment have two different exchange bias coupling directions 91a, 91b. The exchange bias coupling direction 91a is parallel to the reference coordinate X axis, the exchange bias coupling direction 91b is parallel to the reference coordinate Y axis, and the external magnetic field direction 90 during field annealing is 45 degrees with respect to the reference coordinate X axis.

As shown in FIG. 11B, the magnetic field sensor of the present invention includes at least one X-axis sense The measuring unit 410, the at least one Y-axis sensing unit 420, and the at least one Z-axis sensing unit 430, wherein the X-axis sensing unit 410 is composed of four sensing cells 411-414, and four senses The cells 411 to 414 are interconnected to each other to form a Wheatstone Bridge. The Y-axis sensing unit 420 is composed of four sensing cells 421 to 424, and the four sensing cells 421 to 424 are interconnected with each other. As a Winston bridge, the Z-axis sensing unit 430 is also composed of four sensing cells 431-434, and the four sensing cells 431-434 are interconnected with each other to form a Wheatstone bridge. The three sensing units 410, 420, and 430 sense different axial magnetic field changes, respectively.

For the X-axis sensing unit 410, the long-axis direction and freedom of the sensing cells 411-414 The layer magnetization directions 82 are the same, and all are parallel reference coordinates Y-axis. The reference layer magnetization directions 92" of the sensing cells 411 and 413 are the same (toward the negative X-axis direction). The reference layer magnetization directions 92' of the sensing cells 412 and 414 are the same (toward the positive X-axis direction). The layout of this embodiment In other words, the reference layer magnetization direction 92" of the sensing cells 411 and 413 and the reference layer magnetization direction 92' of the sensing cells 412 and 414 are both perpendicular to the long axis direction and the free layer magnetization direction 82.

For the Y-axis sensing unit 420, the long-axis direction and freedom of the sensing cells 421-424 The layer magnetization directions 82 are the same, and are all parallel reference coordinate X-axis (toward the positive X-axis direction). The reference layer magnetization directions 92' of the sensing cells 421 and 423 are the same (toward the positive Y-axis direction). The reference layer magnetization directions 92" of the sensing cells 422 and 424 are the same (toward the negative Y-axis direction). The reference layer magnetization direction 92' of the sensing cells 421 and 423 and the reference layer magnetization direction of the sensing cells 422 and 424 are 92" Both are perpendicular to the long axis direction and the free layer magnetization direction 82.

For the Z-axis sensing unit 430, the long-axis direction and freedom of the sensing cells 431-434 The layer magnetization directions 82 are the same, and may all be parallel reference coordinates Y-axis (toward the positive Y-axis direction). The reference layer magnetization directions 92' of the four sensing cells 431-434 are all the same (toward the positive X-axis direction), both perpendicular to the long axis direction and the free layer magnetization direction 82. The long axis direction of the Z-axis sensing cells 431 to 434 may be any direction, preferably an integer multiple of 45 degrees.

In this example, the annealing method can be performed by the field annealing process 160 and FIG. 9 in FIG. In the field annealing process 260 or the field annealing process 360 in FIG. 10, the exchange bias coupling direction can be determined by the component direction of the applied magnetic field 90 in the long axis axis of the sensing cell, so there are two different exchange bias couplings. Directions 91a, 91b.

It should be noted that the above embodiments may also have different changes, for example, the sensing cell 411, The free layer magnetization directions of 413, 431, 433 may be opposite to the free layer magnetization directions of the sensing cells 412, 414, 432, 434, ie, toward the negative Y-axis direction. The free layer magnetization directions of the sensing cells 422, 424 may be opposite to the free layer magnetization directions of the sensing cells 421, 423, that is, toward the negative X-axis direction, depending on the needs of the invention. On the other hand, it should be noted that although the four sensing cells in each sensing unit in the above embodiment are designed to be interconnected with each other to form a Wheatstone bridge, the design is only a preferred embodiment of the present invention. In actual applications, the sensing cells in the sensing unit may also be only juxtaposed or serialized, and the number of sensing cells per unit in the figure is also merely an example. In other embodiments, it may also have Different numbers of sensing cells are set.

Example two

12A and 12B respectively illustrate three-axis magnetics according to another embodiment of the present invention A side view of the field sensor element and its corresponding top view. The difference between this embodiment and the foregoing embodiment lies in the way in which the cells are sensed and the direction of the exchange bias and the direction of the applied magnetic field. As shown in FIG. 12B, in the field annealing in the embodiment, the external magnetic field direction 90 is oriented toward the positive Y-axis direction, and the sensing cells of the X-axis sensing unit 510 and the Y-axis sensing unit 520 are both set to The X-axis and the Y-axis are at an angle of 45 degrees, and the Z-axis sensing unit 530 is disposed in the same manner as the foregoing embodiment, and the long-axis direction is parallel to the Y-axis direction. With such a sensed cell arrangement, each of the sensing units 510, 520, and 530 will have the same exchange bias coupling direction 91 (toward the positive Y-axis direction), in the same direction as the external magnetic field direction 90.

As shown in FIG. 12B, the triaxial magnetic field sensor component of the present invention includes at least one The X-axis sensing unit 510, the at least one Y-axis sensing unit 520, and the at least one Z-axis sensing unit 530, wherein the X-axis sensing unit 510 is composed of four sensing cells 511-514. The four sensing cells 511-514 are interconnected with each other to form a Wheatstone bridge. The Y-axis sensing unit 520 is composed of four sensing cells 521-524, and the four sensing cells 521-524 are interconnected with each other. Into a Wheatstone Bridge, Z The axial sensing unit 530 is also composed of four sensing cells 531-534, and the four sensing cells 531-534 are interconnected with each other to form a Wheatstone bridge. The three sensing units 510, 520, and 530 sense different axial magnetic field changes, respectively.

For the X-axis sensing unit 510, the long-axis directions of the sensing cells 511 and 513 and The direction of the layer magnetization 82 is the same, and both are at a 45-degree angle with respect to the reference coordinate X-axis. The long-axis directions of the sensing cells 512 and 514 and the magnetization direction of the free layer are the same, and are all at a 135-degree angle with respect to the reference coordinate X-axis. direction. As such, the long axis directions of the sensing cells 511 and 513 are perpendicular to the long axis directions of the sensing cells 512 and 514. The reference layer magnetization direction 92' of the sensing cells 511-514 is perpendicular to the external magnetic field direction 90 during field annealing, wherein the reference layer magnetization direction 92" of the sensing cells 511 and 513 faces the positive X-axis direction, sensing the cell 512 and The reference layer magnetization direction 92' of 514 is oriented toward the negative Y-axis direction.

For the Y-axis sensing unit 520, the long-axis directions of the sensing cells 521 and 523 and The direction of magnetization of the layers is the same, which is a direction at a negative angle of 45 degrees with respect to the X axis of the reference coordinate. The long axis directions of the sensing cells 522 and 524 and the magnetization direction of the free layer are the same, and both are at a positive 45 degree angle with the reference coordinate X axis. In the direction, the long axis directions of the sensing cells 521 and 523 are perpendicular to the long axis directions of the sensing cells 522 and 524. The reference layer magnetization directions 92' of the sensing cells 521 to 524 are all the same (toward the positive X-axis direction), perpendicular to the direction of the external magnetic field 90 during field annealing. In this example, the annealing mode 60 of Fig. 6 is also used to apply the applied magnetic field throughout, so that the exchange bias coupling direction 91 is in the same direction as the external magnetic field direction 90.

For the Z-axis sensing unit 530, the long-axis direction and freedom of the sensing cells 531~534 The layer magnetization directions 82 are the same, and are all parallel reference coordinate Y-axis (toward the positive Y-axis direction). The reference layer magnetization directions 92' of the four sensing cells 531-534 are all the same (toward the positive X-axis direction), both perpendicular to the long axis direction and the free layer magnetization direction 82. In this example, the annealing mode 60 of Fig. 6 is also used to apply the applied magnetic field throughout, so that the exchange bias coupling direction 91 is in the same direction as the external magnetic field direction 90.

It should be noted that the above embodiments may also have different changes, for example, sensing cells 521~524 The free layer magnetization direction can be turned to be completely reversed, or the reference layer magnetization direction 92' of the sensing cells 511 to 514 is turned to be completely reversed, that is, toward the negative X-axis direction, depending on the requirements of the invention. On the other hand, it should be noted that although the four sensing cells in each sensing unit in the above embodiment are designed to be interconnected into one another Wheatstone bridge, however, the design is only a preferred embodiment of the present invention. In practical applications, the sensing cells in the sensing unit may also be only juxtaposed or serialized, and each unit in the figure The number of four sensing cells is also merely an illustration, and in other embodiments, it may have a different number of sensing cell settings.

For the first and second examples of the present invention, the film structure of each sensing cell All of the same and have the same length and width dimensions, so that only a single mask and a single etching step can be used to simultaneously define each sensing cell in each sensing unit shown in the figure on a single wafer, thus The design of the invention can achieve the effects of simplifying the process and reducing the cost.

Next, please refer to FIG. 13, which is an enlarged schematic view of FIG. 11A and FIG. 11B. The orientation of the sensing cell on the substrate protrusion and the magnetization direction of its reference layer and free layer can be more clearly shown. As shown in Fig. 13, the sensing cells 431 to 434 are paired on the inclined faces 402a provided on both sides of the protruding portion 402. The sensing cells 431 to 434 are arranged such that their long axis directions are parallel to the Y axis, and the reference layer magnetization direction is parallel to the slope 402a. More specifically, the free layer magnetization direction 82 is oriented in the positive Y-axis direction, and the reference layer magnetization direction 92' produces a component x on the X-axis and a component z on the Z-axis. Therefore, the sensing cells 431 to 434 located on the inclined surface can be affected by the external magnetic field of the Z-axis, resulting in a change in the magnetization direction 82 of the free layer, thereby measuring the magnetic field change in the Z-axis. It should be noted that in the present invention, the protrusion 402 can also be designed in a recessed manner, so that a bevel can be provided for the sensing cells 431-434.

The above description is only a preferred embodiment of the present invention, and the scope of the patent application according to the present invention is Equal variations and modifications are intended to be within the scope of the present invention.

1‧‧‧sensory cell

10‧‧‧Fixed layer

12‧‧‧ fixed layer

14‧‧‧Orthogonal coupling layer

16‧‧‧ reference layer

18‧‧‧ spacer

20‧‧‧Free layer

Claims (27)

A magnetoresistive film layer structure comprising: a fixed layer; a free layer; a fixed layer interposed between the fixed layer and the free layer and in direct contact with the fixed layer; and an orthogonal coupling layer Between the fixed layer and the free layer, and in direct contact with the fixed layer; a reference layer between the orthogonal coupling layer and the free layer, and in direct contact with the orthogonal coupling layer, wherein The magnetization direction of the fixed layer and the magnetization direction of the reference layer are perpendicular to each other; and a spacer layer interposed between the reference layer and the free layer and in direct contact with the reference layer and the free layer. The magnetoresistive film layer structure according to claim 1, wherein a cobalt metal layer is further disposed between the orthogonal coupling layer and the fixed layer and between the orthogonal coupling layer and the reference layer. The magnetoresistive film layer structure according to claim 2, wherein a base metal layer is provided between the cobalt metal layer and the fixed layer or between the cobalt metal layer and the reference layer. The magnetoresistive film layer structure according to claim 3, wherein a ferromagnetic material layer is disposed between the cobalt metal layer and the base metal layer. The magnetoresistive film layer structure according to claim 1, wherein a ferromagnetic material layer and a base metal are provided between the orthogonal coupling layer and the fixed layer or between the orthogonal coupling layer and the reference layer. Floor. The magnetoresistive film layer structure according to claim 1, wherein the pinned layer is formed on a substrate. The magnetoresistive film layer structure according to claim 6, wherein the substrate and the fixing layer further comprise an adhesive layer and a seed layer. The magnetoresistive film layer structure according to claim 1, wherein the magnetoresistive film layer structure is a three-dimensional film layer structure having long and short axes, and each layer in the magnetoresistive film layer structure has The same plane size. The magnetoresistive film layer structure according to claim 1, wherein a magnetization direction of the reference layer has an angle θ with a magnetization direction of the free layer, and the angle θ is between 0 degrees and 180 degrees. Any angle. The magnetoresistive film layer structure according to claim 9, wherein the included angle θ is an integral multiple of 45 degrees. The magnetoresistive film layer structure according to claim 1, wherein the orthogonal coupling layer comprises nickel iron oxide, iron oxide, nickel oxide, cobalt iron oxide or magnesium oxide. The magnetoresistive film layer structure according to claim 1, wherein the pinned layer is composed of an antiferromagnetic material. A two-axis magnetic field sensor comprising: a substrate; at least one first sensing cell, comprising the first, second, third, fourth or fifth item according to the patent application scope The structure of the magnetoresistive film layer is disposed on a plane of the substrate for sensing a change of a magnetic field in a first axial direction; and at least one second sensing cell is included in the first claim according to the scope of the patent application. The magnetoresistive film layer structure of claim 2, 3, 4 or 5, which is disposed on a plane of the substrate for sensing a second axial magnetic field change, wherein the first sensing cell and the second The sensing cells have a long axis and a short axis, and the long axis direction of the first sensing cell and the long axis direction of the second sensing cell are perpendicular to each other. The biaxial magnetic field sensor according to claim 13, wherein a long axis direction of the first sensing cell is parallel to a free layer magnetization direction of the first sensing cell, and a length of the second sensing cell is The axial direction is parallel to the free layer magnetization direction of the second sensing cell. The biaxial magnetic field sensor according to claim 14, wherein the reference layer magnetization direction of the first sensing cell has a first angle with the long axis direction of the first sensing cell, the second sense The reference layer magnetization direction of the cell has a second angle with the long axis direction of the second sensor cell. The two-axis magnetic field sensor of claim 15, wherein the first angle is the same as the second angle. The two-axis magnetic field sensor according to claim 13 , wherein the plurality of first sensing cells form a first sensing unit for sensing the magnetic field change of the first axial direction, and the plurality of The second sensing cell forms a second sensing unit for sensing the change of the magnetic field in the second axial direction. The two-axis magnetic field sensor of claim 13, wherein the plurality of first sensing cells are interconnected into a first Wheatstone bridge, and the plurality of second sensing cells are interconnected into a second Wheatstone Bridge. A three-axis magnetic field sensor comprising: a substrate; at least one first sensing cell comprising a magnetoresistive film layer structure according to claim 1, 2, 3, 4 or 5, which is disposed on a plane of the substrate for sensing a first axial magnetic field change; at least one second sensing cell comprising a magnetoresistive film layer structure according to claim 1, 2, 3, 4 or 5, wherein the substrate is disposed on the substrate a magnetic field change for sensing a second axial direction; at least one third sensing cell comprising a magnetoresistive film layer structure according to claim 1, 2, 3, 4 or 5; And a slope of the substrate is configured to sense a third axial magnetic field change; wherein the first sensing cell, the second sensing cell, and the third sensing cell both have a long axis and a short axis And the long axis direction of the first sensing cell, the long axis direction of the second sensing cell, and the long axis direction of the third sensing cell are perpendicular to each other. The three-axis magnetic field sensor component of claim 19, wherein a long axis direction of the first sensing cell is parallel to a magnetization direction of the free layer of the first sensing cell, the second sensing The long axis direction of the cell is parallel to the magnetization direction of the free layer of the second sensing cell, and the long axis direction of the third sensing cell is parallel to the magnetization direction of the free layer of the third sensing cell. The three-axis magnetic field sensor component of claim 20, wherein a magnetization direction of the reference layer of the first sensing cell has a first angle with a long axis direction of the first sensing cell, The magnetization direction of the reference layer of the second sensing cell has a second angle with the long axis direction of the second sensing cell, and the magnetization direction of the reference layer of the third sensing cell and the third sensing cell The long axis direction has a third angle. The three-axis magnetic field sensor component of claim 21, wherein the first angle, The second angle and the third angle are the same. The three-axis magnetic field sensor component of claim 22, wherein the first angle, the second angle, and the third angle are 90 degrees. The three-axis magnetic field sensor component of claim 21, wherein the third angle is different from the first angle and the second angle. The three-axis magnetic field sensor component of claim 24, wherein the first angle and the second angle are 45 degrees, and the third angle is 90 degrees. The three-axis magnetic field sensor component of claim 19, wherein the plurality of first sensing cells form a first sensing unit for sensing a change in the magnetic field of the first axial direction, the plurality of The second sensing unit is configured to sense a second magnetic field change, and the plurality of third sensing cells form a third sensing unit for sensing the third Axial magnetic field changes. The three-axis magnetic field sensor component of claim 19, further comprising a plurality of the first sensing cells interconnected into a first Wheatstone bridge, wherein the plurality of second sensing cells are interconnected into one The second Wheatstone bridge interconnects the plurality of third sensing cells into a third Wheatstone bridge.