WO2011074488A1 - Magnetic sensor - Google Patents

Abstract

Disclosed is a magnetic sensor having better disturbance magnetic field resistance than conventional ones. Specifically disclosed is a magnetic sensor provided with a magnetoresistive effect element (13) which is connected between electrode pads (11, 12) and produces a magnetoresistive effect, and a permanent magnet layer (14) for supplying a bias magnetic field to the magnetoresistive effect element (13). The magnetoresistive effect element (13) comprises a first region (20) and a second region (21). A first bias magnetic field (H1) is supplied from the permanent magnet layer (14) to the first region (20) in the direction orthogonal to the sensitivity axis direction (X1-X2) of the magnetoresistive effect element (13), and a second bias magnetic field (H2) is supplied from the permanent magnet layer (14) to the second region (21) in the direction opposite to that of the first bias magnetic field (H1).

Description

Magnetic sensor

The present invention relates to a magnetic sensor excellent in disturbance magnetic field resistance.

A magnetic sensor using a magnetoresistive effect element can be used as a geomagnetic sensor for detecting geomagnetism incorporated in a mobile device such as a mobile phone.

Patent Documents 1 and 2 disclose inventions related to a magnetic sensor including a magnetoresistive effect element. For example, Patent Document 1 discloses a magnetic sensor having a magnetoresistive element and a permanent magnet layer. The magnetization direction of the free magnetic layer constituting the magnetoresistive element is aligned in one direction by the bias magnetic field from the permanent magnet layer.

FIG. 6 is a result of an experiment on disturbance magnetic field resistance performed using the magnetic sensor having the configuration shown in FIG.

As shown in FIG. 7, the magnetic sensor includes a magnetoresistive effect element 1 and permanent magnet layers 2 and 2 arranged on both sides in the longitudinal direction (X direction) of the magnetoresistive effect element 1. As shown in FIG. 7, a bias magnetic field H <b> 7 in the X direction is supplied to the magnetoresistive element 1 from the permanent magnet layers 2 and 2. For this reason, the magnetization direction of the free magnetic layer constituting the magnetoresistive element 1 is aligned with the X direction. On the other hand, the magnetization direction of the fixed magnetic layer constituting the magnetoresistive element 1 is the sensitivity axis direction and is fixed in the Y direction.

When an external magnetic field acts from the sensitivity axis direction, the magnetization direction of the free magnetic layer changes and the resistance value of the magnetoresistive effect element 1 changes.

On the other hand, the element length direction (X) of the magnetoresistive effect element 1 orthogonal to the sensitivity axis direction (Y) is the disturbance magnetic field direction (leakage magnetic field direction).

In the experiment, the X1 direction is the + direction, the X2 direction is the-direction, the Y1 direction is the + direction, the Y2 direction is the-direction, no disturbance magnetic field is applied (disturbance magnetic field; 0 Oe), and a +5 Oe disturbance magnetic field is applied. In the state (application of a magnetic field of 5 Oe in the X1 direction) and in the state of applying a disturbance magnetic field of -5 Oe (application of a magnetic field of 5 Oe in the X2 direction), the sensitivity axis direction of the magnetic sensor shown in FIG. A detection magnetic field was applied (applied while changing the magnetic field within a range of 6 Oe at the maximum in the Y1 direction to 6 Oe at the maximum in the Y2 direction), and the resistance change rate (ΔMR) was measured.

As shown in FIG. 6, it was found that ΔMR fluctuates from when the disturbance magnetic field is 0 Oe when the disturbance magnetic field is applied with +5 Oe and when the disturbance magnetic field is applied with −5 Oe. This is because when the disturbance magnetic field is applied in the same direction as the magnetization direction of the free magnetic layer, the magnetization of the free magnetic layer becomes stronger due to the disturbance magnetic field, and ΔMR becomes smaller than when the disturbance magnetic field is set to 0 Oe. On the other hand, when the disturbance magnetic field is applied in the direction opposite to the magnetization direction of the free magnetic layer, the magnetization of the free magnetic layer becomes weaker due to the disturbance magnetic field, and ΔMR becomes larger than when the disturbance magnetic field is set to 0 Oe. Because.

As described above, conventionally, the variation in the resistance change of the magnetoresistive effect element 1 with respect to the detected magnetic field becomes large depending on whether or not the disturbance magnetic field acts on the free magnetic layer, and it is necessary to improve the disturbance magnetic field resistance. It was.

JP 2006-66821 A JP 63-205584 A

The present invention is for solving the above-described conventional problems, and in particular, an object of the present invention is to provide a magnetic sensor that is more excellent in disturbance magnetic field resistance than the conventional one.

The magnetic sensor in the present invention is
A magnetoresistive effect element that exhibits a magnetoresistive effect connected between the electrode pads, and a permanent magnet layer for supplying a bias magnetic field to the magnetoresistive effect element,
The magnetoresistive effect element has a first region and a second region, and the first region includes a first region extending from the permanent magnet layer in a direction perpendicular to the sensitivity axis direction of the magnetoresistive effect element. A bias magnetic field is supplied, and a second bias magnetic field in a direction opposite to the first bias magnetic field is supplied from the permanent magnet layer to the second region.

This makes it possible to effectively improve the magnetic field resistance against the disturbance magnetic field from the direction orthogonal to the sensitivity axis direction.

In the present invention, the magnetoresistive effect element is formed in an elongated shape having an element length that is orthogonal to the element width compared to the element width, and is opposed to the element length direction to the first region. It is preferable that the second region is provided, and the first bias magnetic field and the second bias magnetic field are supplied to the magnetoresistive element in the element length direction. Thereby, a bias magnetic field can be appropriately supplied to the magnetoresistive effect element, and a magnetic sensor excellent in sensitivity and disturbance magnetic field resistance can be obtained.

In the present invention, the magnetoresistive element includes a pinned magnetic layer whose magnetization direction is fixed, and a free magnetic layer that is stacked on the pinned magnetic layer via a nonmagnetic layer and whose magnetization direction is variable, The magnetization direction of the fixed magnetic layer as the sensitivity axis direction in the first region and the second region of the magnetoresistive effect element is the same direction and the element width direction, and the first region and the It is preferable that the bias magnetic field orthogonal to the magnetization direction of the pinned magnetic layer and opposite to each other is supplied to the second region.
The present invention is preferably applied to the giant magnetoresistive element (GMR element) described above.

In the present invention, the permanent magnet layers are arranged in the order of the first permanent magnet layer, the second permanent magnet layer, and the third permanent magnet layer at intervals in the element length direction.
A first region of the magnetoresistive effect element is located between the first permanent magnet layer and the second permanent magnet layer, and the second permanent magnet layer and the third permanent magnet layer A second region of the magnetoresistive element is located between
Each permanent magnet layer is magnetized in the same direction and in the element width direction, the first bias magnetic field is generated between the first permanent magnet layer and the second permanent magnet layer, and the second It is preferable that the second bias magnetic field is generated between the permanent magnet layer and the third permanent magnet layer. Thereby, it is possible to effectively generate the bias magnetic fields supplied to the first region and the second region in opposite directions.

In the present invention, the side surfaces of the permanent magnet layers facing each other in the element length direction are substantially parallel and inclined from the element width direction toward the element length direction, and the second permanent magnet layer An intersection of the first side face facing the first permanent magnet layer and the second side face facing the third permanent magnet layer, or the first side face and the second side face. When the first side surface and the second side surface are viewed from the intersection of the extended virtual lines, the first side surface and the second side surface are inclined toward the opposite direction of the element length direction. Is preferred.

Thereby, the bias magnetic fields supplied to the first region and the second region can be more effectively generated in opposite directions.

In the present invention, each permanent magnet layer can be configured to be opposed to the magnetoresistive element in the height direction. Alternatively, the magnetoresistive element is divided into a first element piece including the first region and a second element piece including the second region with a space therebetween, and each element portion and each The permanent magnet layers can be arranged alternately in the element length direction.

In the present invention, a bridge circuit is configured by the four magnetoresistive elements, and each magnetoresistive element is preferably applied to a configuration having the first region and the second region. As a result, the output can be increased, the disturbance magnetic field resistance can be improved, and a magnetic sensor excellent in detection sensitivity can be obtained.

According to the present invention, it is possible to provide a magnetic sensor that is more resistant to disturbance magnetic fields than conventional ones.

(A) is a top view which shows the structure of a part of magnetic sensor in this embodiment, (b) is a circuit diagram of the magnetic sensor in this embodiment, FIG. 1 is a partially enlarged plan view showing a part of the magnetic sensor shown in FIG. (A) is a longitudinal sectional view of the magnetic sensor of the present embodiment, cut in the height direction (film thickness direction) along the line AA shown in FIG. 2 and viewed from the arrow direction. Is a variation of The partial top view of the magnetic sensor in another embodiment which shows the shape of the permanent magnet layer different from FIG. 2, The partial longitudinal cross-sectional view of the magnetoresistive effect element in this embodiment, Experimental results on disturbance magnetic field resistance performed using the magnetic sensor having the configuration shown in FIG. The schematic diagram of the magnetic sensor used for the experiment of FIG.

FIG. 1A is a plan view showing the configuration of a part of the magnetic sensor in this embodiment, FIG. 1B is a circuit diagram of the magnetic sensor in this embodiment, and FIG. 2 shows a part of the magnetic sensor shown in FIG. 3A is an enlarged partial plan view, and FIG. 3A is a cross-sectional view taken along the line AA shown in FIG. (B) and (c) are modified examples, FIG. 4 is a partial plan view of a magnetic sensor in another embodiment showing the shape of a permanent magnet layer different from FIG. 2, and FIG. It is a fragmentary longitudinal cross-section of the magnetoresistive effect element in a form.

The magnetic sensor 10 including the magnetoresistive effect element in the present embodiment is configured as a geomagnetic sensor mounted on a mobile device such as a mobile phone.

The X-axis direction and the Y-axis direction shown in each figure indicate two directions orthogonal to each other in the horizontal plane, and the Z-axis direction indicates a direction orthogonal to the horizontal plane.

As shown in FIG. 1A, the magnetic sensor 10 includes an electrode pad 11, 12, a magnetoresistive effect element 13 electrically connected between the electrode pads 11, 12, and a bias magnetic field applied to the magnetoresistive effect element 13. And a plurality of permanent magnet layers 14 for supplying.

In the magnetoresistive element 13 shown in FIG. 1A, a plurality of element extending portions 13a and 13b extending in a strip shape in the Y1-Y2 direction are opposed to each other with an interval in the X1-X2 direction. It is the shape where the edge part by the side of Y1 of 13a, 13b was connected in the connection part 13c. Each of the element extending portions 13a and 13b has an elongated shape in which the element length (length dimension in the Y1-Y2 direction) orthogonal to the element width is longer than the element width (width dimension in the X1-X2 direction). Further, it is preferable that more element extending portions are provided than in FIG. 1, and the end portions on the Y1 side or Y2 side of each element extending portion are connected to form a meander-shaped magnetoresistive element 13. .

As shown in FIG. 5, the magnetoresistive element 13 (GMR element) is formed by laminating, for example, an antiferromagnetic layer 33, a pinned magnetic layer 34, a nonmagnetic layer 35, and a free magnetic layer 36 in this order from the bottom. The surface of the free magnetic layer 36 is covered with a protective layer 37. The magnetoresistive element 13 is formed by sputtering, for example.

The antiferromagnetic layer 33 is made of an antiferromagnetic material such as an IrMn alloy (iridium-manganese alloy). The pinned magnetic layer 34 is formed of a soft magnetic material such as a CoFe alloy (cobalt-iron alloy). The pinned magnetic layer 34 is preferably formed of a laminated ferrimagnetic structure. The nonmagnetic layer 35 is made of Cu (copper) or the like. The free magnetic layer 36 is made of a soft magnetic material such as a NiFe alloy (nickel-iron alloy). The protective layer 37 is made of Ta (tantalum) or the like. The laminated structure of the magnetoresistive effect element 13 shown in FIG. 5 is an example, and another laminated structure may be used.

In the magnetoresistive element 13, the magnetization direction (P direction) of the pinned magnetic layer 34 is fixed by antiferromagnetic coupling between the antiferromagnetic layer 33 and the pinned magnetic layer 34. In the embodiment shown in FIG. 5, the pinned magnetization direction (P direction) of the pinned magnetic layer 34 faces the X2 direction. The direction parallel to the fixed magnetization direction of the fixed magnetic layer 34 (that is, the X1-X2 direction) is the sensitivity axis direction.

In this embodiment, as will be described later, the magnetoresistive element 13 has a first region 20 and a second region 21, but the fixed magnetization direction (P of the fixed magnetic layer 34 in each region 20, 21). Since the directions are all in the same direction, the magnetization control for the pinned magnetic layer 34 can be easily performed.

On the other hand, the magnetization direction of the free magnetic layer 36 varies depending on the external magnetic field. The magnetization of the free magnetic layer 36 receives a bias magnetic field from the permanent magnet layer 14 described later, and is aligned in a direction parallel to Y1-Y2 (no magnetic field state).

When an external magnetic field acts from the sensitivity axis direction, the magnetization direction of the free magnetic layer 36 changes in the direction of the external magnetic field. At this time, when the fixed magnetization direction of the fixed magnetic layer 34 and the magnetization direction of the free magnetic layer 36 are the same, the electric resistance value becomes the minimum value, and the fixed magnetization direction of the fixed magnetic layer 34 and the magnetization direction of the free magnetic layer 36 are In the reverse direction, the electric resistance value becomes the maximum value.

In the embodiment shown in FIG. 1A, a plurality of permanent magnet layers 14 are formed in substantially the same shape. As shown in FIG. 1A, the permanent magnet layers 14 are arranged at intervals in the Y1-Y2 direction, and a part of each permanent magnet layer 14 is formed by the first element extension portion 13a or the second element extension portion 13a. It faces the element extension 13b in the height direction.

As shown in FIG. 1A, the permanent magnet layer 14 facing the first element extending portion 13a in the height direction is a permanent magnet layer denoted by reference numerals 14a to 14d. Here, the permanent magnet layer 14a and the permanent magnet layer 14b adjacent in the Y1-Y2 direction are arranged so as to be shifted in the X1-X2 direction. The permanent magnet layer 14c is arranged so as to be shifted in the X1 direction with respect to the permanent magnet layer 14b so as to face the permanent magnet layer 14a in the Y1-Y2 direction. Further, the permanent magnet layer 14d is arranged so as to be shifted in the X2 direction with respect to the permanent magnet layer 14c so as to face the permanent magnet layer 14b in the Y1-Y2 direction.

Further, the permanent magnet layer 14 facing the second element extension portion 13b in the height direction is a permanent magnet layer denoted by reference numerals 14a, 14f, 14c, and 14e. As shown in FIG. 1A, the permanent magnet layer 14e is pulled in the Y1-Y2 direction from the center point in the X1-X2 direction of the first element extension 13a and the second element extension 13b. The permanent magnet layer 14d is provided at a line symmetrical position with the center line OO as the axis of symmetry. The permanent magnet layer 14f is provided at a line symmetrical position of the permanent magnet layer 14b with the center line OO as the axis of symmetry.

Here, the three permanent magnet layers 14a, 14b, and 14c shown in the enlarged view of FIG. 2 are sequentially arranged in the Y1 direction from the Y2 side in the first permanent magnet layer 14a, the second permanent magnet layer 14b, and the third permanent magnet. Set as layer 14c.

As shown in FIG. 2, the magnetoresistive effect element 13 (first element extending portion 13 a) located between the first permanent magnet layer 14 a and the second permanent magnet layer 14 b in the plan view is the first The magnetoresistive effect element 13 (the first element extending portion 13a) that constitutes one area 20 and is located between the second permanent magnet layer 14b and the third permanent magnet layer 14c is the second area 21. Is configured.

As shown in FIG. 2, the first permanent magnet layer 14a, the second permanent magnet layer 14b, and the third permanent magnet layer 14c all have X1 side end portions 14a1, 14b1, and 14c1 as N poles, and X2 side end portions. 14a2, 14b2, and 14c2 are magnetized to the S pole, and the magnetization directions are the same. The magnetization direction is the element width direction (X1-X2).

As shown in FIG. 2, a first side surface 22 is formed on the second permanent magnet layer 14b from the X1 side end portion 14b1 toward the Y2 side end portion 14b3, and from the X1 side end portion 14b1 to the Y1 side end portion 14b4. A second side surface 23 is formed toward the surface. The first side surface 22 and the second side surface 23 are inclined from the element width direction (X1-X2) toward the element length direction (Y1-Y2). The side surfaces 22 and 23 are formed in a straight line shape.

As shown in FIG. 2, when the first side surface 22 and the second side surface 23 are viewed from the intersection 25 of an imaginary line 24 obtained by extending the first side surface 22 and the second side surface 23, the first side surface 22. The second side surface 23 and the second side surface 23 are inclined in the direction opposite to the element length direction (Y1-Y2). Alternatively, when a straight reference line 26 is drawn from the intersection point 25 in the element width direction (X1-X2), the first side surface 22 and the second side surface 23 are arranged in the Y1-Y2 direction via the reference line 26. It is in an opposing positional relationship.

As shown in FIG. 2, the first side surface 22 and the second side surface 23 both face the magnetoresistive effect element 13 (first element extending portion 13 a) in the height direction in plan view. It is provided at the position.

Further, the first permanent magnet layer 14a is formed with a side surface (opposing surface) 27 facing the first side surface 22 formed in the second permanent magnet layer 14b in the Y1-Y2 direction. The side surface 27 of the first permanent magnet layer 14a and the first side surface 22 of the second permanent magnet layer 14b are provided substantially in parallel. Therefore, the side surface 27 of the first permanent magnet layer 14a is provided with the second permanent magnet layer 14a. The magnet layer 14 b is formed to be inclined in the same direction as the first side surface 22.

Further, the third permanent magnet layer 14c has a side surface (opposing surface) 28 facing the second side surface 23 formed in the second permanent magnet layer 14b in the Y1-Y2 direction. The side surface 28 of the third permanent magnet layer 14c and the second side surface 23 of the second permanent magnet layer 14b are provided substantially in parallel. Therefore, the side surface 28 of the third permanent magnet layer 14c is provided with the second permanent magnet layer 14c. The magnet layer 14 b is formed to be inclined in the same direction as the second side surface 23.

As shown in FIG. 2, the side surface 27 of the first permanent magnet layer 14a and the side surface 28 of the third permanent magnet layer 14c are in the height direction with the magnetoresistive effect element 13 (first element extension portion 13a). Are provided at opposite positions.

As shown in FIG. 2, a first bias magnetic field H1 is generated from the first side surface 22 of the second permanent magnet layer 14b toward the side surface 27 of the first permanent magnet layer 14a. Further, a second bias magnetic field H2 is generated from the second side surface 23 of the second permanent magnet layer 14b toward the side surface 28 of the third permanent magnet layer 14c. The first bias magnetic field H1 is generated in the Y2 direction, and the second bias magnetic field H2 is generated in the Y1 direction.

Therefore, the first bias magnetic field H1 is supplied to the first region 20 of the magnetoresistive effect element 13 (first element extension portion 13a), and the second bias magnetic field H2 is supplied to the second region 21. Supplied. The first bias magnetic field H1 and the second bias magnetic field H2 are opposite to each other and are orthogonal to the fixed magnetization direction (P) of the fixed magnetic layer 34 (see FIG. 5).

As described above, the magnetization direction of the free magnetic layer 36 formed in the first region 20 of the magnetoresistive effect element 13 (first element extension portion 13a) is aligned in the Y2 direction and formed in the second region 21. The magnetization direction of the free magnetic layer 36 is aligned with the Y1 direction.

As shown in FIG. 1, the first region 20 and the second region 21 are alternately formed in the element length direction (Y1-Y2) in the magnetoresistive effect element 13, and as shown in FIG. It is preferable that the number of the regions 20 and the second regions 21 is the same.

Next, a change in resistance of the magnetoresistive effect element 13 when a detection magnetic field from the sensitivity axis direction and a disturbance magnetic field from a direction orthogonal to the sensitivity axis direction act will be described.

The sensitivity axis direction of the magnetoresistive effect element 13 shown in FIGS. 1 and 2 is the X1-X2 direction. When the detection magnetic field acts in the X1 direction, the magnetization direction of the free magnetic layer 36 changes from the Y1-Y2 direction to the X1 direction. Since the fixed magnetization direction (P) of the fixed magnetic layer 34 is the X2 direction, when the magnetization direction of the free magnetic layer 36 changes from the Y1-Y2 direction to the X1 direction, the electric resistance value gradually increases, and the free magnetic layer When the magnetization direction 36 and the fixed magnetization direction (P) of the pinned magnetic layer 34 are reversed, the electric resistance value becomes the maximum value.

On the other hand, when the detection magnetic field acts in the X2 direction, the magnetization direction of the free magnetic layer 36 changes from the Y1-Y2 direction to the X2 direction. Since the fixed magnetization direction (P) of the fixed magnetic layer 34 is the X2 direction, when the magnetization direction of the free magnetic layer 36 changes from the Y1-Y2 direction to the X2 direction, the electric resistance value gradually decreases, and the free magnetic layer When the magnetization direction 36 and the fixed magnetization direction (P) of the pinned magnetic layer 34 are the same, the electric resistance value becomes the minimum value.

Next, as shown in FIG. 2, when the disturbance magnetic field H3 acts in the Y1 direction orthogonal to the sensitivity axis direction, the magnetization direction of the free magnetic layer 36 in the first region 20 is the Y2 direction. The magnetization of the free magnetic layer 36 at 20 is weakened by the disturbance magnetic field H3. When the detection magnetic field acts in the sensitivity axis direction (X1-X2) with the disturbance magnetic field applied in this way, the electrical resistance change in the first region 20 becomes larger than that without the disturbance magnetic field (FIG. 6 also). (Refer to the change in resistance (or ΔMR) in the first region corresponds to the disturbance magnetic field (−5 Oe) graph of FIG. 6).

On the other hand, since the magnetization direction of the free magnetic layer 36 in the second region 21 is the Y1 direction, the magnetization of the free magnetic layer 36 in the second region 21 is enhanced by the disturbance magnetic field H3. When the detection magnetic field acts in the sensitivity axis direction (X1-X2) in the state where the disturbance magnetic field is applied in this way, the electrical resistance change in the second region 21 becomes smaller than that in the case where there is no disturbance magnetic field (also in FIG. 6). (Refer to the change in resistance (or ΔMR) in the second region corresponds to the disturbance magnetic field (+5 Oe) graph in FIG. 6).

As shown in FIG. 2, when the disturbance magnetic field H4 acts in the Y2 direction orthogonal to the sensitivity axis direction, the magnetization of the free magnetic layer 36 in the first region 20 is strengthened by the disturbance magnetic field H4, and the sensitivity axis direction When the detection magnetic field acts on (X1-X2), the change in electrical resistance in the first region 20 becomes smaller than in the case where there is no disturbance magnetic field.

On the other hand, the magnetization of the free magnetic layer 36 in the second region 21 is weakened by the disturbance magnetic field H4, and when the detection magnetic field acts in the sensitivity axis direction (X1-X2), the electrical resistance change in the second region 21 is It becomes larger than the state without a disturbance magnetic field.

As described above, in this embodiment, when the disturbance magnetic fields H3 and H4 are applied, one magnetoresistive element 13 has a region where the magnetization of the free magnetic layer 36 is strengthened and a region where the magnetization of the free magnetic layer 36 is weakened. Since each of them exists, the resistance change in the entire magnetoresistive effect element 13 can be made closer to the resistance change in a state where a disturbance magnetic field does not act as compared with the conventional structure in which the magnetization direction of the free magnetic layer is aligned in one direction. It becomes possible to improve the disturbance magnetic field resistance.

As shown in the longitudinal sectional view of FIG. 3A, the magnetoresistive effect element 13 is formed on a substrate 29 with an insulating layer 30 interposed therebetween. Further, an insulating layer 31 is provided on the magnetoresistive effect element 13 so as to fill the space between the element extending portions 13a and 13b. The insulating layer 31 is also formed on the magnetoresistive effect element 13 to form a flat surface. ing. Then, each permanent magnet layer 14 is formed on the planarized surface of the insulating layer 31. The permanent magnet layer 14 is, for example, CoPt or CoPtCr, but the material is not particularly limited.

3A, the insulating layer 31 is present in the height direction (Z1-Z2) between the magnetoresistive effect element 13 and the permanent magnet layer 14, but the thickness of the insulating layer 31 is not limited. Since the horizontal component of the bias magnetic field flowing from the permanent magnet layer 14 to the magnetoresistive effect element 13 becomes weaker, it is preferable to form the insulating layer 31 positioned on the magnetoresistive effect element 13 thin. For example, the film thickness of the insulating layer 31 located between the magnetoresistive effect element 13 and the permanent magnet layer 14 is set to about 0.03 to 0.5 μm.

Alternatively, as shown in FIG. 3B, a part of the magnetoresistive effect element 13 may be removed, and the permanent magnet layer 14 may be formed on the removed recess 13d. For example, the protective layer 37, the free magnetic layer 36, and the nonmagnetic layer 35 shown in FIG. 3B, the insulating layer 31 shown in FIG. 3A is not interposed between the magnetoresistive effect element 13 and the permanent magnet layer 14, and the permanent magnet layer 36 is formed on the side surface of the free magnetic layer 36. 14 can be disposed, so that a bias magnetic field can be appropriately supplied to the free magnetic layer 36.

However, in the case of FIG. 3B and FIG. 3C to be described next, the permanent magnet layers 14a and 14c are separated in the left-right direction (X1-X2), and the current is supplied to the first element extending portion 13a, The second element extension 13b is prevented from flowing through the permanent magnet layers 14a and 14c.

Alternatively, as shown in FIG. 3C, the magnetoresistive effect element 13 at the position where the permanent magnet layer 14 is formed is all deleted, and the magnetoresistive effect element 13 is replaced with the first element piece 13e including the first region 20 and The second element piece 13f including the second region 21 may be divided, and the permanent magnet layer 14 may be interposed between the first element piece 13e and the second element piece 13f.

However, as shown in FIG. 3B, the effect of the bias magnetic field on the pinned magnetic layer 34 can be reduced without dividing the pinned magnetic layer 34, and the fluctuation in the pinned magnetization direction (P) of the pinned magnetic layer 34 can be reduced. The detection accuracy can be improved, which is preferable.

It is also possible to form the permanent magnet layer 14 under the magnetoresistive element 13. That is, the permanent magnet layer 14 is formed on the substrate 29, the space between the permanent magnet layers 14 is filled with an insulating layer to form a planarized surface, and the magnetoresistive element 13 can be formed on the planarized surface.

The shape of the permanent magnet layer 14 shown in FIGS. 1 and 2 is an example, and is not limited to this shape, but in the present embodiment, the first magnet layer 14 supplied to the first region 20 of the magnetoresistive effect element 13 is used. It is necessary to make the shape and arrangement of the permanent magnet layer such that one bias magnetic field H1 and the second bias magnetic field H2 supplied to the second region 21 are in opposite directions.

The shape of each permanent magnet layer 40 shown in FIG. 4A is similar to the shape obtained by cutting each permanent magnet layer 14 shown in FIG. 2 in the Y1-Y2 direction from the approximate center in the X1-X2 direction.
The permanent magnet layer 41 shown in FIG. 4B has a triangular shape.

The permanent magnet layers 40 and 41 shown in FIGS. 4 (a) and 4 (b) are all magnetized in the same manner as in FIG. 2, with the X1 end on the N pole and the X2 end on the S pole. The magnetic direction is the same. Also, the side surfaces of the permanent magnet layers 40 and 41 facing each other in the element length direction (Y1-Y2) shown in FIGS. 4A and 4B are substantially parallel and the element width direction (X1-X2) It is inclined toward the length direction.

Then, when the first permanent magnet layers 40a and 41a, the second permanent magnet layers 40b and 41b, and the third permanent magnet layers 40c and 41c are arranged in the order of the Y1 direction from the Y2 side, the second permanent magnet layer 40b. , 41b, the first side surfaces 40b1, 41b1 facing the first permanent magnet layer 40a, and the second side surfaces 40b2, facing the third permanent magnet layers 40c, 41c of the second permanent magnet layers 40b, 41b. 41b2 is inclined obliquely in the direction opposite to the element length direction (Y1-Y2) when viewed from the intersections B and C of the first side surfaces 40b1 and 41b1 and the second side surfaces 40b2 and 41b2. Is extended.

Therefore, also in the configuration shown in FIGS. 4A and 4B, the first bias magnetic field H1 in the Y2 direction is supplied to the first region 20 of the magnetoresistive effect element 13 as in FIG. The region 21 is supplied with the second bias magnetic field H2 in the Y1 direction.

The inclination angle of the side surface in each permanent magnet layer shown in FIGS. 2, 4A, and 4B is 5 ° to from the element width direction (X1-X2) to the element length direction (Y1-Y2). It is preferable to tilt about 60 °.

In FIG. 4C, each permanent magnet layer 42 has a rod shape extending in parallel with the X1-X2 direction. Each permanent magnet layer 42 is formed slightly apart in the X1-X2 direction so as not to overlap the magnetoresistive effect element 13 in the height direction. In this embodiment, the end portions of the permanent magnet layers 42 facing the magnetoresistive effect element 13 are curved in a convex shape, but the shape of the end portions is not limited. When the first permanent magnet layer 42a, the second permanent magnet layer 42b, and the third permanent magnet layer 42c are arranged in the order of arrangement in the Y1 direction from the Y2 side, the second permanent magnet layer 42b has an end portion 42b1 to the second permanent magnet layer 42b. The bias magnetic field H5 acting toward the end portion 42a1 of one permanent magnet layer 42a has the same direction as the element length direction (Y1-Y2) when passing through the first region 20 of the magnetoresistive effect element 13. To the bias magnetic field H6 acting from the end portion 42b1 of the second permanent magnet layer 42b toward the end portion 42c1 of the third permanent magnet layer 42c. When passing through the region 21, a vertical component in the same direction as the element length direction (Y 1 -Y 2) acts, and the bias magnetic field supplied to the first region 20 and the second region 21 of the magnetoresistive element 13. H5 and H6 are in opposite directions You have me.

In this embodiment, as shown in FIGS. 2 and 4, the magnetization directions of the permanent magnet layers are all the same. For this reason, each permanent magnet layer 14 can be magnetized easily and appropriately.

In all of the embodiments shown in FIGS. 1, 2 and 4, the X1 side end of each permanent magnet layer is the N pole and the X2 side end is the S pole.

In the above-described embodiment, the permanent magnet layers are separated, but a part of each permanent magnet layer may be connected.

As shown in the circuit diagram of FIG. 1B, in this embodiment, a bridge circuit is provided in which four magnetoresistive elements 13 shown in FIG. 1 are provided. The magnetoresistive effect element 13 is electrically connected between the electrode pads constituting the input terminal vdd, the output terminals V1 and V2, and the ground terminal GND. The arrow direction of each magnetoresistive element 13 shown in FIG. 1B indicates the fixed magnetization direction (P) of the fixed magnetic layer 34. Each magnetoresistive element 13 includes a first region 20 and a second region 21 into which bias magnetic fields H1 and H2 in opposite directions shown in FIG. Therefore, each magnetoresistive element 13 shown in FIG. 1B has excellent disturbance magnetic field resistance. By using the bridge circuit, the detection output can be increased, and a magnetic sensor having excellent detection accuracy can be configured due to excellent disturbance magnetic field resistance.

Moreover, in the magnetic sensor of the present embodiment, the magnetization direction of all the permanent magnet layers arranged for each magnetoresistive element 13 can be set to the same direction. Therefore, production efficiency can be increased and a magnetic sensor with excellent detection accuracy can be obtained.

Although the sensitivity axis direction of the magnetic sensor 10 shown in FIG. 1 is the X1-X2 direction, the sensitivity axis direction can be changed to the Y1-Y2 direction by rotating the magnetic sensor 10 shown in FIG. 1 by 90 degrees.

H1 1st bias magnetic field H2 2nd bias magnetic field H3, H4 Disturbance magnetic field 10 Magnetic sensor 11, 12 Electrode pad 13 Magnetoresistive effect element 13a, 13b Element extension part 14, 40, 41, 42 Permanent magnet layer 14a, 40a , 41a, 42a First permanent magnet layer 14b, 40b, 41b, 42b Second permanent magnet layer 14c, 40c, 41c, 42c Third permanent magnet layer 20 First region 21 Second region 22 First Side surface 23 Second side surface 33 Antiferromagnetic layer 34 Pinned magnetic layer 35 Nonmagnetic layer 36 Free magnetic layer

Claims (8)

A magnetoresistive effect element that exhibits a magnetoresistive effect connected between the electrode pads, and a permanent magnet layer for supplying a bias magnetic field to the magnetoresistive effect element,
The magnetoresistive effect element has a first region and a second region, and the first region includes a first region extending from the permanent magnet layer in a direction perpendicular to the sensitivity axis direction of the magnetoresistive effect element. A magnetic sensor, wherein a bias magnetic field is supplied, and a second bias magnetic field in a direction opposite to the first bias magnetic field is supplied from the permanent magnet layer to the second region. The magnetoresistive effect element is formed in an elongated shape having an element length that is orthogonal to the element width as compared to the element width, and the first region and the second region are opposed to each other in the element length direction. The magnetic sensor according to claim 1, wherein the first bias magnetic field and the second bias magnetic field are supplied to the magnetoresistive element in the element length direction. The magnetoresistive effect element includes a pinned magnetic layer whose magnetization direction is fixed, and a free magnetic layer that is stacked on the pinned magnetic layer via a nonmagnetic layer and has a variable magnetization direction, and the magnetoresistive effect element The magnetization direction of the pinned magnetic layer as the sensitivity axis direction in the first region and the second region of the first region and the second region is the same direction and in the element width direction, and the first region and the second region 3. The magnetic sensor according to claim 2, wherein the bias magnetic field orthogonal to the magnetization direction of the pinned magnetic layer and opposite to each other is supplied. Each permanent magnet layer is arranged in the order of the first permanent magnet layer, the second permanent magnet layer, and the third permanent magnet layer at intervals in the element length direction,
A first region of the magnetoresistive effect element is located between the first permanent magnet layer and the second permanent magnet layer, and the second permanent magnet layer and the third permanent magnet layer A second region of the magnetoresistive element is located between
Each permanent magnet layer is magnetized in the same direction and in the element width direction, the first bias magnetic field is generated between the first permanent magnet layer and the second permanent magnet layer, and the second The magnetic sensor according to claim 2, wherein the second bias magnetic field is generated between the permanent magnet layer and the third permanent magnet layer. The side surfaces of the permanent magnet layers facing each other in the element length direction are substantially parallel and inclined from the element width direction toward the element length direction, and the first permanent magnet layer of the second permanent magnet layer is inclined. An intersection of the first side surface facing the permanent magnet layer and the second side surface facing the third permanent magnet layer, or an imaginary line extending the first side surface and the second side surface 5. The magnetism according to claim 4, wherein the first side surface and the second side surface are inclined toward opposite directions of the element length direction when the first side surface and the second side surface are viewed from the intersection of each other. Sensor. The magnetic sensor according to claim 4, wherein each permanent magnet layer is disposed to face the magnetoresistive element in a height direction. The magnetoresistive effect element is divided into a first element piece including the first region and a second element piece including the second region with an interval between each element portion and each permanent magnet. The magnetic sensor according to claim 4, wherein the layers are alternately arranged in the element length direction. The magnetic sensor according to claim 1, wherein a bridge circuit is configured by the four magnetoresistive elements, and each magnetoresistive element includes the first region and the second region.

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