JP6502802B2 - Sensor, information terminal, microphone, blood pressure sensor and touch panel - Google Patents

Description

  Embodiments of the present invention relate to a sensor, an information terminal, a microphone, a blood pressure sensor and a touch panel.

  Pressure sensors using magnetic layers have been developed. In pressure sensors, it is desirable to expand the dynamic range.

JP, 2013-205403, A

  Embodiments of the present invention provide a sensor, an information terminal, a microphone, a blood pressure sensor and a touch panel capable of expanding a dynamic range.

According to an embodiment of the invention, the sensor comprises a membrane part, a sensing element and a magnetic field generator. The membrane portion is deformable. The sensing element is fixed to a part of the film portion, and includes a first magnetic layer, a second magnetic layer, and an intermediate layer provided between the first magnetic layer and the second magnetic layer. Including. The magnetic field generator includes a wire separated from the sensing element via an air gap, and applies a magnetic field to the sensing element.
According to an embodiment of the invention, the sensor comprises a membrane part, a sensing element and a magnetic field generator. The membrane portion is deformable. The sensing element is fixed to a part of the film portion, and includes a first magnetic layer, a second magnetic layer, and an intermediate layer provided between the first magnetic layer and the second magnetic layer. Including. The magnetic field generation unit applies a magnetic field to the detection element including a wire separated from the film unit.
According to an embodiment of the present invention, the sensor comprises a membrane part, a sensing element, a magnetic field generator and a circuit part. The membrane portion is deformable. The sensing element is fixed to a part of the film portion, and includes a first magnetic layer, a second magnetic layer, and an intermediate layer provided between the first magnetic layer and the second magnetic layer. Including. The magnetic field generator applies a magnetic field to the sensing element. A first circuit electrically connected to one of the first magnetic layer and the second magnetic layer and supplying a second current to the magnetic field generation unit according to a first current flowing through the sensing element; And a second circuit electrically connected to the magnetic field generation unit and monitoring the second current.

FIG. 1A to FIG. 1E are schematic views illustrating the pressure sensor according to the first embodiment. It is a circuit diagram which illustrates the pressure sensor concerning a 1st embodiment. It is a schematic diagram which illustrates the characteristic of the pressure sensor concerning a 1st embodiment. It is a schematic diagram which illustrates the characteristic of the pressure sensor concerning a 1st embodiment. FIG. 5A to FIG. 5D are schematic views illustrating the operation of the pressure sensor according to the first embodiment. FIG. 6A to FIG. 6E are schematic views illustrating the pressure sensor according to the second embodiment. It is a schematic perspective view which illustrates a part of pressure sensor concerning an embodiment. It is a schematic perspective view which illustrates a part of another pressure sensor which concerns on embodiment. It is a schematic perspective view which illustrates a part of another pressure sensor which concerns on embodiment. It is a schematic perspective view which illustrates a part of another pressure sensor which concerns on embodiment. It is a schematic perspective view which illustrates a part of another pressure sensor which concerns on embodiment. It is a schematic perspective view which illustrates a part of another pressure sensor which concerns on embodiment. It is a schematic perspective view which illustrates a part of another pressure sensor which concerns on embodiment. It is a schematic diagram which illustrates the microphone concerning a 3rd embodiment. It is a schematic cross section which illustrates another microphone concerning a 3rd embodiment. FIGS. 16A and 16B are schematic views illustrating the blood pressure sensor according to the fourth embodiment. It is a schematic diagram which illustrates the touch panel concerning a 5th embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio of sizes between parts, and the like are not necessarily the same as the actual ones. In addition, even in the case of representing the same portion, the dimensions and ratios may be different from one another depending on the drawings.
In the specification of the present application and the drawings, the same elements as those described above with reference to the drawings are denoted by the same reference numerals, and the detailed description will be appropriately omitted.

First Embodiment
FIG. 1A to FIG. 1E are schematic views illustrating the pressure sensor according to the first embodiment.
FIG. 1A is a perspective view. FIG. 1 (c) is a plan view seen from the direction of arrow AR of FIG. 1 (a). FIG.1 (b) is the A1-A2 line sectional view of FIG.1 (a) and FIG.1 (c). 1 (d) and 1 (e) are cross-sectional views of part of the pressure sensor.

  As shown in FIG. 1A, the pressure sensor 110 according to the present embodiment includes a film unit 70d, a sensing element 50, and a magnetic field generation unit 60.

  The film part 70d is deformable. The sensing element 50 is fixed to a part of the film unit 70d.

  The direction from the film unit 70 d toward the detection element 50 is taken as the Z-axis direction. One axis perpendicular to the Z-axis direction is taken as the X-axis direction. A direction perpendicular to the Z-axis direction and the X-axis direction is taken as a Y-axis direction.

  The film portion 70d has an outer edge 70r. In the pressure sensor 110, a holder 70s is further provided. The holding portion 70s holds the outer edge 70r. A slit may be provided between the holding portion 70s and the outer edge 70r. That is, the holding portion 70s holds the outer edge 70r continuously or discontinuously. The film part 70d may have a hole (slit).

  For example, the length (thickness) of the film portion 70d in the Z-axis direction is shorter (thin) than the length (thickness) of the holding portion 70s in the Z-axis direction.

  As shown in FIG. 1B, for example, a part of a substrate (such as a silicon substrate) is removed to provide a cavity 70h. Thereby, the film part 70d is formed. For example, the portion not removed is the holding unit 70s.

  As shown in FIG. 1A, in this example, a plurality of sensing elements 50 (such as first to fourth sensing elements 50a to 50d) are provided. In this example, the second detection element 50b is aligned with the first detection element 50a along the X-axis direction. The fourth detection element 50c is aligned with the third detection element 50c along the X-axis direction. The area where the third sensing element 50c and the fourth sensing element 50d are provided is separated from the area where the first sensing element 50a and the second sensing element 50b are provided in the Y-axis direction.

  For example, the second sensing element 50b may be electrically connected to the first sensing element 50a. The first detection element 50a and the second detection element 50b may be included in one detection unit 50u. The number of detection elements 50 aligned in the X-axis direction may be three or more. The number of detection elements 50 included in the detection unit 50u may be three or more.

  As shown in FIG. 1B, the first sensing element 50a (sensing element 50) is provided on part of the film unit 70d. The first sensing element 50a (sensing element 50) includes a first magnetic layer 10, a second magnetic layer 20, and an intermediate layer 30 (first intermediate layer). The intermediate layer 30 (first intermediate layer) is provided between the first magnetic layer 10 and the second magnetic layer 20. In this example, the second magnetic layer 20 is disposed between the first magnetic layer 10 and the film portion 70d. In the embodiment, the first magnetic layer 10 may be disposed between the second magnetic layer 20 and the film portion 70d.

  As shown in FIG. 1 (b), the second sensing element 50b is provided on another part of the film part 70d. The second sensing element 50b includes a third magnetic layer 10b, a fourth magnetic layer 20b, and a second intermediate layer 30b. The second intermediate layer 30 b is provided between the third magnetic layer 10 b and the fourth magnetic layer 20 b. In this example, the fourth magnetic layer 20b is disposed between the third magnetic layer 10b and the film portion 70d. In the embodiment, the third magnetic layer 10b may be disposed between the fourth magnetic layer 20b and the film portion 70d.

  As shown in FIG. 1D, the third sensing element 50c is provided on another part of the film part 70d. The third sensing element 50c includes a fifth magnetic layer 10c, a sixth magnetic layer 20c, and a third intermediate layer 30c. The third intermediate layer 30c is provided between the fifth magnetic layer 10c and the sixth magnetic layer 20c. For example, the sixth magnetic layer 20c is disposed between the fifth magnetic layer 10c and the film portion 70d. The fifth magnetic layer 10c may be disposed between the sixth magnetic layer 20c and the film portion 70d.

  As shown in FIG. 1 (e), the fourth sensing element 50d is provided on another part of the film part 70d. The fourth sensing element 50d includes a seventh magnetic layer 10d, an eighth magnetic layer 20d, and a fourth intermediate layer 30d. The fourth intermediate layer 30d is provided between the seventh magnetic layer 10d and the eighth magnetic layer 20d. For example, the eighth magnetic layer 20d is disposed between the seventh magnetic layer 10d and the film portion 70d. In the embodiment, the seventh magnetic layer 10d may be disposed between the eighth magnetic layer 20d and the film portion 70d.

  For example, the first electrode 58a, the second electrode 58b, and the insulating film 58c are provided. A sensing element 50 (first sensing element 50a) is provided in a part between these electrodes. The insulating film 58c is provided on another part between these electrodes. Current is supplied to these electrodes. The resistance between the first magnetic layer 10 and the second magnetic layer 20 can be detected by this current.

  The first magnetic layer 10 has magnetization (first magnetization). The second magnetic layer 20 has magnetization (second magnetization). The magnetization (first magnetization) of the first magnetic layer 10 changes in accordance with the deformation of the film portion 70d. The first magnetic layer 10 is, for example, a magnetization free layer. The magnetization (second magnetization) of the second magnetic layer 20 is fixed. The second magnetic layer 20 is, for example, a reference layer (for example, a magnetization fixed layer). The magnetization of the second magnetic layer 20 may change according to the deformation of the film portion 70d.

  In the sensing element 50 (first sensing element 50a), a strain according to the deformation of the film portion 70d is applied to the first magnetic layer 10. In the first magnetic layer 10, a change in the magnetization direction occurs according to the applied strain. This change in magnetization is due to, for example, the inverse magnetostrictive effect. The angle between the direction of the first magnetization of the first magnetic layer 10 and the direction of the second magnetization of the second magnetic layer 20 changes according to the applied strain. The electrical resistance between the first magnetic layer 10 and the second magnetic layer 20 changes in accordance with the change in angle between the magnetization directions. This change is due to, for example, the magnetoresistive effect (MR effect). By detecting the change in the electrical resistance, the strain applied to the sensing element 50 can be detected.

  Similarly, in the second to third sensing elements 50b to 50d, a change in electrical resistance occurs in accordance with the applied strain. Also in these sensing elements, the applied strain can be detected by detecting a change in electrical resistance.

  A current for detecting a change in electrical resistance is supplied to the sensing element 50 (first sensing element 50a or sensing unit 50u) via the first electrode 58a and the second electrode 58b.

  As shown in FIG. 1C, in this example, the film portion 70d (outer edge 70r) is substantially polygonal (square, specifically rectangular). The outer edge 70r of the film portion 70d includes a first side 70s1, a second side 70s2, a third side 70s3, and a fourth side 70s4.

  The first side 70s1 extends in a first direction (in this example, the X-axis direction). The second side 70s2 is separated from the first side 70s1 in the second direction. The second direction intersects the first direction. In this example, the second direction is the Y-axis direction. The second side 70s1 extends in the first direction (X-axis direction). The third side 70s3 extends in the second direction (Y-axis direction). The fourth side 70s4 is separated from the third side 70s3 in the first direction (X-axis direction), and extends in the second direction (Y-axis direction).

  In this example, the distance along the first direction between the third side 70s3 and the fourth side 70s4 is longer than the distance along the second direction between the first side 70s1 and the second side 70s2. The film portion 70d is substantially rectangular, and the first side 70s1 and the second side 70s2 are long sides. The third side 70s3 and the fourth side 70s4 are short sides. In the embodiment, at the outer edge 70r, a curved portion may be provided between the side and the side. For example, the strength of the film unit 70d is improved. The film portion 70b may have a square shape. The film portion 70d may have a circular shape.

  When pressure is applied to the film portion 70d, a large strain (anisotropic strain) occurs in the vicinity of the outer edge 70r of the film portion 70d. By arranging the sensing element 50 in the vicinity of the outer edge 70r of the film portion 70d, a large strain is added to the sensing element 50, and high sensitivity can be obtained. In particular, when the length of one of the film portions 70d is longer than the length in the other direction (that is, when the shape is anisotropic), particularly large distortion occurs in a portion along the major axis of the outer edge 70r. It occurs. For this reason, particularly high sensitivity can be obtained by arranging the sensing element 50 in a portion along the long side of the outer edge 70r.

  For example, the film portion 70d has an outer edge 70r, and the sensing element 50 (first sensing element 50a) is closest to the first outer edge portion 70r1 of the outer edge 70r. A large distortion is obtained in the vicinity of the first outer edge portion 70r1. By arranging the sensing element 50 in the vicinity of the first outer edge portion 70r1, high sensitivity can be obtained.

  The outer edge 70r of the film portion 70d includes a first side 70s1 extending in the first direction (X-axis direction). At this time, the sensing element 50 is closest to the first side 70s1 of the outer edge 70r. Large distortion is obtained in the vicinity of the first side 70s1. By arranging the detection element 50 in the vicinity of the first side 70s1, high sensitivity can be obtained.

  In the embodiment, a magnetic field generation unit 60 is provided. The magnetic field generator 60 applies a magnetic field Ha to the sensing element 50.

  In this example, a wire 65 is provided as the magnetic field generation unit 60. That is, the magnetic field generation unit 60 includes the wiring 65. The current Ia is supplied to the wiring 65. The wire 65 is separated from the sensing element 50. The wire 65 is supplied with a current Ia different from the current flowing to the sensing element 50. The wiring 65 is insulated from at least one of the first electrode 58a and the second electrode 58b (at least one of the first magnetic layer 10 and the second magnetic layer 20). A magnetic field Ha (eg, a current magnetic field) is generated from the wiring 65 based on the current Ia. A magnetic field Ha is applied to the sensing element 50 (first magnetic layer 10). Thereby, the magnetization of the first magnetic layer 10 changes in accordance with the strain according to the deformation of the film portion 70 d and the applied magnetic field Ha. For example, by controlling the current Ia, the detection dynamic range can be expanded by the detection element 50.

  According to the embodiment, it is possible to provide a pressure sensor whose dynamic range can be expanded.

  In the embodiment, the sensing element 50 (first sensing element 50a) is disposed, for example, in the vicinity of the first side 70s1 extending in the first direction. At this time, the magnetization of the first magnetic layer 10 of the first sensing element 50a intersects with the second direction. Thus, for example, even when the film portion 70d is changed to either a convex shape or a concave shape, the magnetization generated in the first magnetic layer 10 changes due to the strain generated in the vicinity of the first side 70s1.

  When the sensing element 50 (first sensing element 50a) is disposed in the vicinity of the first side 70s1 extending in the first direction, the magnetic field Ha applied to the first sensing element 50a intersects, for example, the first direction. Thereby, for example, the controllability of the change of the first magnetization due to the magnetic field Ha and the distortion is enhanced. That is, in the state in which the first magnetic layer 10 is strained, the change in the direction of the first magnetization with respect to the change in the magnetic field Ha can be made large.

  In the embodiment, for example, the magnetic field Ha is along the second direction (the direction intersecting the first direction in which the first side 70s1 extends). That is, the magnetic field Ha includes a component in the second direction perpendicular to the first direction. Such a magnetic field Ha is applied to the sensing element 50 (first magnetic layer 10). Thereby, the magnetization of the first magnetic layer 10 changes in accordance with the strain according to the deformation of the film portion 70 d and the applied magnetic field Ha. As a result, the dynamic range can be expanded efficiently and with high precision.

  Furthermore, in the embodiment, the sensing element 50 (first sensing element 50a) is disposed between the wiring 65 and the film unit 70d. Thereby, the magnetic field Ha by the wiring 65 can be efficiently applied to the detection element 50 (first detection element 50a). Thus, the dynamic range can be expanded more efficiently and with higher precision.

  As described above, the film part 70d has the outer edge 70r including the first side 70s1 extending in the first direction, and the detection element 50 is closest to the first side 70s1 of the outer edge 70r. The interconnection 65 has an extending portion 65p extending in the first direction. It is desirable that the sensing element 50 be disposed between the extension portion 65p and the film portion 70d. For example, a magnetic field Ha in the Y-axis direction is obtained by the extended portion 65p, and the magnetic field Ha is efficiently applied to the first magnetic layer 10.

  In the embodiment, the outer edge 70r of the film portion 70d may include a curved portion. Also in this case, the sensing element 50 is closest to the first outer edge portion 70r1 of the outer edge 70r. At least a portion of the first outer edge portion 70r1 may be curved. At this time, the wiring 65 has an extended portion 65p along the first outer edge portion 70r1. The sensing element 50 is disposed between the extension portion 65p and the film portion 70d. As a result, a magnetic field Ha in the direction intersecting the first outer edge portion 70 r 1 is obtained, and the magnetic field Ha is efficiently applied to the first magnetic layer 10.

  In this example, another wire 65A is further provided. A third sensing element 50c and a fourth sensing element 50d are provided between the wire 65A and the film portion 70d. The arrangement of each of the third detection element 50c and the fourth detection element 50d can be the same as the arrangement of each of the first detection element 50a and the second detection element 50b, so the description will be omitted. The operation of the wiring 65A can be similar to that of the wiring 65, so the description will be omitted. A magnetic field is applied to the third sensing element 50c and the fourth sensing element 50d by the wiring 65A. Thereby, the dynamic range can be expanded.

  For example, in the plurality of sensing elements 50, the applied magnetic fields Ha may be different from one another. For example, the magnetic field Ha applied to one sensing element 50 is larger than the magnetic field Ha applied to another sensing element 50. For example, detection of a large pressure is performed by the one detection element 50 described above. Detection of small pressure is performed by the above-mentioned another sensing element 50. Depending on the direction of the magnetic field Ha, the one sensing element 50 described above and the other sensing element 50 described above may be interchanged. For example, by selecting the output of each of these sensing elements 50, sensing of a wide dynamic range can be performed.

  For example, in one sensing element 50, the magnitude of the magnetic field Ha may be changed. For example, a plurality of operation modes are provided, and the magnitude of the magnetic field Ha in the plurality of operation modes is changed. A wide dynamic range can be detected by employing a plurality of operation modes.

  Such an operation may be performed by, for example, a control unit (circuit unit) or the like. Furthermore, in the circuit unit, the current may be monitored and detection may be performed as follows.

  In an embodiment, pressure sensor 110 may further include circuitry 68. The circuit unit 68 is electrically connected to the first magnetic layer 10, the second magnetic layer 20, one end 65e of the wiring 65, and the other end 65f of the wiring 65.

  In the embodiment, in a state in which the first conductive portion is electrically connected to the second conductive portion, the first conductive portion physically contacts the second conductive portion, and the first conductive portion and the second conductive portion In addition to the state in which current flows between the first and second conductive portions, another conductive portion (including a switching element or the like) is provided between the first conductive portion and the second conductive portion. It also includes a state in which current flows between the conductive portion and the second conductive portion.

  In this example, the circuit unit 68 is electrically connected to the first magnetic layer 10 via the first electrode 58 a electrically connected to the first magnetic layer 10. The circuit unit 68 is electrically connected to the second magnetic layer 20 via the second electrode 58 b electrically connected to the second magnetic layer 20.

Hereinafter, an example of the pressure sensor 110 including the circuit unit 68 will be described.
FIG. 2 is a circuit diagram illustrating the pressure sensor according to the first embodiment.
As shown in FIG. 2, the pressure sensor 110 according to the embodiment includes a detection element 50 (for example, a detection unit 50 u), a magnetic field generation unit 60 (for example, a wire 65), and a circuit unit 68. The circuit unit 68 includes a first circuit 68a and a second circuit 68b.

  The first circuit 68 a is electrically connected to one of the first magnetic layer 10 and the second magnetic layer 20. In this example, the first circuit 68 a is electrically connected to the first magnetic layer 10. The first circuit 68 a may be electrically connected to the second magnetic layer 20. That is, the input end of the first circuit 68 a is electrically connected to one end of the sensing element 50.

  The second circuit 68 b is electrically connected to the magnetic field generation unit 60 (for example, the wiring 65). In this example, the second circuit 68b is electrically connected to one end of the magnetic field generation unit 60 (for example, the wiring 65). The output portion of the first circuit 68 a is connected to the other end of the magnetic field generation unit 60.

  In this example, the circuit unit 68 further includes a resistor unit 68c and a power supply unit 68d. One end of the power supply 68 d is electrically connected to one end of the resistor 68 c. The other end of the resistance portion 68c is electrically connected to one end of the sensing element 50 and the input end of the first circuit 68a. The other end of the detection element 50 is electrically connected to the other end of the power supply unit 68 d. The output end of the first circuit 68a is electrically connected to the other end of the magnetic field generation unit 60 (for example, the wiring 65).

  The first circuit 68a is a feedback circuit. The second circuit 68 b is a current monitor circuit.

  For example, the film unit 70d is deformed according to the pressure from the outside. The resistance of the sensing element 50 changes in accordance with the deformation of the film portion 70d. For example, in the first circuit 68a, a current (first current I1) flows according to the deformation of the film unit 70d. The first circuit 68a supplies the second current I2 corresponding to the first current I1 flowing through the first circuit 68a to the magnetic field generation unit 60 (wiring 65). The second current I2 changes according to the deformation of the film part 70d. The second circuit unit 68b monitors the second current I2. By monitoring the second current I2, the pressure for deforming the film unit 70d is detected.

  Thus, the first circuit portion 68a is electrically connected to one of the first magnetic layer 10 and the second magnetic layer 20, and generates a magnetic field for the second current I2 corresponding to the first current I1 flowing to the sensing element 50. It supplies to the part 60 (for example, the wiring 65). The second circuit 68b is electrically connected to the magnetic field generation unit 60 (for example, the wiring 65) and monitors the second current I2. The pressure is detected by the second current I2 monitored by the second circuit unit 68b.

Hereinafter, an example of the operation of the pressure sensor 110 will be described.
FIG. 3 is a schematic view illustrating characteristics of the pressure sensor according to the first embodiment.
In the state illustrated in FIG. 3, the magnetic field generation unit 60 does not generate the magnetic field Ha. In FIG. 3, the horizontal axis is the strain ε generated in the sensing element 50. The vertical axis is the resistance R of the sensing element 50. The change in resistance R substantially corresponds to the change in resistance between the first magnetic layer 10 and the second magnetic layer 20. In the following description, the first magnetic layer 10 corresponds to the magnetization free layer, and the second magnetic layer 20 corresponds to the magnetization fixed layer. In the following description, when the direction of the strain ε is positive, the resistance R decreases, and when the direction of the strain ε is negative, the resistance R increases.

  In the first strain region ε1, the resistance R changes in accordance with the strain ε. In this region, for example, the magnetization of the magnetization free layer changes according to the strain, and the angle between the magnetization of the magnetization free layer and the magnetization of the magnetization fixed layer changes. On the other hand, in the second strain region ε2 or the third strain region ε3, the resistance R does not change even if the strain ε changes. For example, in the third strain region ε 3, the magnetization of the magnetization free layer is parallel to the magnetization of the magnetization fixed layer or parallel to the direction in which strain is applied, and the angle is Does not change. For example, in the second strain region ε 2, the magnetization of the magnetization free layer is antiparallel to the magnetization of the magnetization fixed layer or perpendicular to the direction in which strain is applied, and the magnitude of strain ε changes. , The angle between the magnetization of the magnetization free layer and the magnetization of the magnetization fixed layer does not change.

  In the first strain region ε1, there is a one-to-one relationship between the pressure to be detected and the strain ε. In this region, there is a one-to-one relationship between the pressure to be detected and the resistance R. The first distortion region ε1 corresponds to the dynamic range DR. By detecting the resistance R in the first strain region ε1, the target pressure is detected.

  When the first strain region ε1 (dynamic range DR) is expanded, the slope (dR / dε) of the resistance-distortion characteristic (R-ε characteristic) is lowered. That is, the detection sensitivity is reduced.

  In the embodiment, the dynamic range DR can be expanded while maintaining high detection sensitivity by providing the magnetic field generation unit 60 (for example, the wiring 65). A magnetic field Ha by the magnetic field generator 60 is applied to the sensing element 50 (for example, the first magnetic layer 10). Thereby, the magnetization (first magnetization) of the first magnetic layer 10 changes due to the influence of the magnetic field Ha in addition to the influence of the strain ε. For example, the magnetic field Ha promotes a change of the first magnetization. Alternatively, the magnetic field Ha suppresses the change of the first magnetization.

FIG. 4 is a schematic view illustrating characteristics of the pressure sensor according to the first embodiment.
In the state illustrated in FIG. 4, the magnetic field generation unit 60 applies the magnetic field Ha to the sensing element 50. In FIG. 4, a plurality of magnetic fields Ha (values and directions are different from each other) are applied to the sensing element 50. The horizontal axis is the strain ε generated in the sensing element 50. The vertical axis is the resistance R of the sensing element 50.

  As shown in FIG. 4, by controlling the magnetic field Ha, it is possible to shift the region where the slope of the R-ε characteristic is high. As a result, the dynamic range DR is expanded. Then, in this shift, the slope of the R-ε characteristic is maintained. That is, by controlling the magnetic field Ha, the dynamic range DR can be expanded while maintaining high detection sensitivity.

  In the embodiment, depending on the direction of the magnetic field Ha, it is also possible to change the slope of the R-ε characteristic. The sensitivity of the sensing element 50 can be adjusted by the magnetic field Ha.

Hereinafter, in the embodiment, an example of detection of pressure when the magnetic field Ha is used will be described. FIG. 5A to FIG. 5D are schematic views illustrating the operation of the pressure sensor according to the first embodiment.
These figures illustrate the R-ε characteristic of the sensing element 50. 5A and 5B correspond to the state where the magnetic field Ha is zero. FIG. 5C corresponds to the state when the magnetic field Ha is applied. FIG. 5D corresponds to the state when a predetermined magnetic field Ha (ie, the magnetic field H3) is applied.

  As shown in FIG. 5A, in the first state ST1 (for example, the initial state), the strain ε is a first strain εA. In the initial state, for example, the pressure to be detected is a predetermined state. The initial state is, for example, a reference state, and the first strain εA may not be zero. In the initial state, the resistor R is a first resistor R1. When the strain ε changes, the resistance R changes.

  FIG. 5B shows the second state ST2. In the second state ST2, the pressure of the detection target is added, and the strain ε is a second strain εB. At this time, the resistor R is the second resistor R2.

  In this state, when the magnetic field Ha is applied, the state illustrated in FIG. 5C is obtained. The R-.epsilon. Characteristic shifts in accordance with the change of the change of the magnetic field Ha (H1 to H2). The change of the magnetic field Ha is changed by, for example, the second current I2 supplied to the magnetic field generation unit 60 (for example, the wiring 65).

  That is, as shown in FIG. 5D, the magnetic field Ha (i.e., the magnetic field H3) is such that the resistance R of the sensing element 50 at the second strain εB is the same as the first resistance R1 corresponding to the first strain εA. It becomes settled. Between the magnetic field H3 (the second current I2 generating the magnetic field H3) which keeps the resistance of the sensing element 50 constant against the change of the strain ε and the strain ε (pressure applied to the pressure sensor 120) applied to the sensing element 50 There is a correlation. By measuring the magnetic field H3 (the second current I2), detection of the pressure applied to the pressure sensor 120 becomes possible. That is, in the embodiment, for example, the detection of the balance method is performed. In this manner, the resistance of the sensing element 50 is balanced.

  For example, in the embodiment, a first current I1 that changes due to a change in the resistance R of the sensing element 50 is detected by the first circuit 68a (feedback circuit). The first circuit 68 a supplies the second current I 2 to the magnetic field generation unit 60 according to the change of the resistance R (that is, the first current I 1). The second current I2 is monitored by the second circuit 68b. For example, a magnetic field Ha is generated such that the resistance R of the sensing element 50 at the second strain εA is the first resistance R1 corresponding to the first strain εA. A second current I2 corresponding to the magnetic field Ha is monitored. It is possible to provide a pressure sensor whose dynamic range can be expanded.

  In the embodiment, in response to the change in resistance of the sensing element 50, current is supplied to the magnetic field generation unit 60 via the feedback circuit. This current corresponds to the pressure to be detected. For example, R-ε specification is controlled such that the resistance R when the second strain εB is applied to the sensing element 50 is maintained at the first resistance R1 when the second strain εB is not applied. The resistance R of the sensing element 50 is balanced. The current (second current I 2) for keeping the resistance R of the sensing element 50 in balance depends on the magnitude of the strain applied to the sensing element 50. That is, this current depends on the pressure to be detected. The target pressure can be detected by monitoring the second current I2 flowing to the magnetic field generation unit 60. In the embodiment, for example, a wide dynamic range can be obtained while maintaining high sensitivity. The pressure sensor according to the embodiment has high sensitivity and a wide detection pressure range.

Second Embodiment
FIG. 6A to FIG. 6E are schematic views illustrating the pressure sensor according to the second embodiment.
FIG. 6A is a perspective view. FIG. 6 (c) is a plan view seen from the direction of arrow AR in FIG. 6 (a). FIG. 6B is a cross-sectional view taken along line A1-A2 of FIGS. 6A and 6C. 6 (d) and 6 (e) are cross-sectional views of part of the pressure sensor.

  As shown in FIG. 6A, the pressure sensor 120 according to the present embodiment also includes a film unit 70d, a sensing element 50, and a magnetic field generation unit 60. In this example, the magnetic field generator 60 includes a coil 66. The film unit 70d and the detection element 50 can be the same as those in the first embodiment, and thus the description thereof is omitted. Below, the coil 66 used as the magnetic field generation part 60 is demonstrated.

  The coil 66 is separated from the sensing element 50. The coil 66 is supplied with a current (current Ia) Ia different from the current flowing to the sensing element 50. The coil 66 is insulated from at least one of the first electrode 58a and the second electrode 58b (at least one of the first magnetic layer 10 and the second magnetic layer 20).

  Also in this example, the film portion 70d has the outer edge 70r. The sensing element 50 (first sensing element 50a) is closest to the first outer edge portion 70r1 of the outer edge 70r. The coil 66 to be the magnetic field generating unit 60 has a winding axis 66x. The axis 66x intersects with the extending direction of the first outer edge portion 70r1. For example, the axis 66x is orthogonal to the extending direction of the first outer edge portion 70r1.

  In this example, the outer edge 70r of the film portion 70d is closest to the first side 70s1 extending in the first direction (X-axis direction). The sensing element 50 (first sensing element 50a) is closest to the first side 70s1 of the outer edge 70r. The axis 66x of the winding of the coil 66 to be the magnetic field generating unit 60 intersects the first direction. The axis 66x is orthogonal to the first direction.

  The coil 66 applies a magnetic field Ha to the sensing element 50 (for example, the first sensing element 50a and the second sensing element 50b). The pressure sensor 120 can also provide a pressure sensor whose dynamic range can be expanded.

  Also in the pressure sensor 120, a circuit unit 68 is provided. The circuit unit 68 includes a first circuit 68a and a second circuit 68b (see FIG. 2). Thus, the operation described with reference to FIG. 5 can be performed. Also in the pressure sensor 120, a wide dynamic range can be obtained while maintaining high sensitivity.

  In the present embodiment, a holder 70s is provided. The holder 70s holds the outer edge 70r of the film 70d. The coil 66 is provided to the holder 70s. The coil 66 is provided, for example, on the holder 70s. In the coil 66, for example, a conductive member is wound. Therefore, the coil 66 is unlikely to be elastically deformed. By providing the coil 66 on the holding portion 70s, the deformation characteristic of the film portion 70d can be maintained. High sensitivity detection is possible.

  For example, the position of the first side 70s1 in the Y-axis direction is between the position of the coil 66 in the Y-axis direction (third direction) and the position of the sensing element 50 (first sensing element 50a) in the Y-axis direction. Be placed.

  In this example, a coil 66A is further provided. The coil 66A applies a magnetic field to the third sensing element 50c and the fourth sensing element 50d. The position of the second side 70s2 in the Y-axis direction is disposed between the position of the coil 66A in the Y-axis direction (third direction) and the position of the third detection element 50c in the Y-axis direction.

  Hereinafter, examples of the sensing element 50 used in the first and second embodiments will be described. In the following description, the description of “material A / material B” indicates a state in which the layer of material B is provided on the layer of material A.

FIG. 7 is a schematic perspective view illustrating a part of the pressure sensor according to the embodiment.
As shown in FIG. 7, in the sensing element 50A, the lower electrode 204, the underlayer 205, the pinning layer 206, the second magnetization fixed layer 207, the magnetic coupling layer 208, the first magnetization fixed layer 209, and the middle The layer 203, the magnetization free layer 210, the cap layer 211, and the upper electrode 212 are arranged in this order. The first magnetization fixed layer 209 corresponds to, for example, the second magnetic layer 20. The magnetization free layer 210 corresponds to, for example, the first magnetic layer 10. The lower electrode 204 corresponds to, for example, the second electrode 58 b. The upper electrode 212 corresponds to, for example, the first electrode 58a. The sensing element 50A is, for example, a bottom spin valve type.

For the base layer 205, for example, a laminated film (Ta / Ru) of tantalum and ruthenium is used. The thickness (length in the Z-axis direction) of this Ta layer is, for example, 3 nanometers (nm). The thickness of this Ru layer is, for example, 2 nm. For the pinning layer 206, for example, an IrMn layer with a thickness of 7 nm is used. For the second magnetization fixed layer 207, for example, a Co ₇₅ Fe ₂₅ layer with a thickness of 2.5 nm is used. For the magnetic coupling layer 208, for example, a Ru layer with a thickness of 0.9 nm is used. For the first magnetization fixed layer 209, for example, a Co ₄₀ Fe ₄₀ B 20 layer with a thickness of 3 nm is used. For the intermediate layer 203, for example, an MgO layer having a thickness of 1.6 nm is used. For the magnetization free layer 210, for example, Co ₄₀ Fe ₄₀ B ₂₀ having a thickness of 4 nm is used. For the cap layer 211, for example, Ta / Ru is used. The thickness of this Ta layer is, for example, 1 nm. The thickness of this Ru layer is, for example, 5 nm.

  For the lower electrode 204 and the upper electrode 212, for example, at least one of aluminum (Al), aluminum-copper alloy (Al-Cu), copper (Cu), silver (Ag), and gold (Au) is used. By using such a material having a relatively small electric resistance as the lower electrode 204 and the upper electrode 212, current can be efficiently supplied to the sensing element 50A. Nonmagnetic materials are used for the lower electrode 204 and the upper electrode 212.

  The lower electrode 204 and the upper electrode 212 are, for example, an underlayer (not shown) for the lower electrode 204 and the upper electrode 212, a cap layer (not shown) for the lower electrode 204 and the upper electrode 212, and the like And at least one of Al, Al-Cu, Cu, Ag, and Au. For example, tantalum (Ta) / copper (Cu) / tantalum (Ta) or the like is used for the lower electrode 204 and the upper electrode 212. By using Ta as the base layer of the lower electrode 204 and the upper electrode 212, for example, the adhesion between the substrate (for example, the film portion 70d) and the lower electrode 204 and the upper electrode 212 is improved. As a base layer for the lower electrode 204 and the upper electrode 212, titanium (Ti), titanium nitride (TiN), or the like may be used.

  By using Ta as a cap layer of the lower electrode 204 and the upper electrode 212, oxidation of copper (Cu) or the like under the cap layer is suppressed. As a cap layer for the lower electrode 204 and the upper electrode 212, titanium (Ti), titanium nitride (TiN), or the like may be used.

  For the base layer 205, for example, a laminated structure including a buffer layer (not shown) and a seed layer (not shown) is used. The buffer layer relieves, for example, surface roughness of the lower electrode 204, the film portion 70d, and the like, and improves the crystallinity of a layer stacked on the buffer layer. The buffer layer is, for example, at least one selected from the group consisting of tantalum (Ta), titanium (Ti), vanadium (V), tungsten (W), zirconium (Zr), hafnium (Hf) and chromium (Cr). Is used. As the buffer layer, an alloy containing at least one material selected from these materials may be used.

  The thickness of the buffer layer in the base layer 205 is preferably 1 nm or more and 10 nm or less. The thickness of the buffer layer is more preferably 1 nm or more and 5 nm or less. If the thickness of the buffer layer is too thin, the buffer effect is lost. When the thickness of the buffer layer is too thick, the thickness of the sensing element 50A becomes excessively thick. A seed layer is formed on the buffer layer, for example, the seed layer has a buffer effect. In this case, the buffer layer may be omitted. For the buffer layer, for example, a Ta layer having a thickness of 3 nm is used.

  The seed layer in the base layer 205 controls the crystal orientation of the layer stacked on the seed layer. The seed layer controls the grain size of the layer laminated on the seed layer. As this seed layer, fcc structure (face-centered cubic structure: face-centered cubic lattice structure), hcp structure (hexagonal close-packed structure: hexagonal close-packed lattice structure) or bcc structure (body-centered cubic structure: body-centered cubic lattice) Metal of the structure) is used.

  By using ruthenium (Ru) of hcp structure, NiFe of fcc structure, or Cu of fcc structure as the seed layer of the underlayer 205, for example, the crystal orientation of the spin valve film on the seed layer is determined. It can be fcc (111) oriented. For the seed layer, for example, a Cu layer with a thickness of 2 nm or a Ru layer with a thickness of 2 nm is used. When the crystal orientation of the layer formed on the seed layer is to be enhanced, the thickness of the seed layer is preferably 1 nm or more and 5 nm or less. The thickness of the seed layer is more preferably 1 nm or more and 3 nm or less. Thereby, the function as a seed layer which improves crystal orientation is fully exhibited.

  On the other hand, for example, when it is not necessary to crystallize the layer formed on the seed layer (for example, when forming an amorphous magnetization free layer), the seed layer may be omitted. As a seed layer, for example, a Cu layer having a thickness of 2 nm is used.

  The pinning layer 206 applies unidirectional anisotropy (unidirectional anisotropy) to the second magnetization fixed layer 207 (ferromagnetic layer) formed on the pinning layer 206, for example. Fix the magnetization. For the pinning layer 206, for example, an antiferromagnetic layer is used. For the pinning layer 206, for example, Ir-Mn, Pt-Mn, Pd-Pt-Mn, Ru-Mn, Rh-Mn, Ru-Rh-Mn, Fe-Mn, Ni-Mn, Cr-Mn-Pt and At least one selected from the group consisting of Ni-O is used. Selected from the group consisting of Ir-Mn, Pt-Mn, Pd-Pt-Mn, Ru-Mn, Rh-Mn, Ru-Rh-Mn, Fe-Mn, Ni-Mn, Cr-Mn-Pt and Ni-O An alloy in which an additional element is further added to at least one of the above may be used. The thickness of the pinning layer 206 is appropriately set. This provides, for example, a sufficiently strong unidirectional anisotropy.

  For example, heat treatment is performed while applying a magnetic field. Thereby, for example, the magnetization of the ferromagnetic layer in contact with the pinning layer 206 is fixed. The magnetization of the ferromagnetic layer in contact with the pinning layer 206 is fixed in the direction of the magnetic field applied during the heat treatment. The heat treatment temperature (annealing temperature) is, for example, equal to or higher than the magnetization fixation temperature of the antiferromagnetic material used for the pinning layer 206. When an antiferromagnetic layer containing Mn is used, Mn may diffuse into a layer other than the pinning layer 206 to reduce the MR ratio. The heat treatment temperature is preferably set to a temperature at which the diffusion of Mn occurs. The heat treatment temperature is, for example, 200 ° C. or more and 500 ° C. or less. The heat treatment temperature is, for example, preferably 250 ° C. or more and 400 ° C. or less.

When PtMn or PdPtMn is used as the pinning layer 206, the thickness of the pinning layer 206 is preferably 8 nm or more and 20 nm or less. The thickness of the pinning layer 206 is more preferably 10 nm or more and 15 nm or less. When IrMn is used as the pinning layer 206, unidirectional anisotropy can be imparted with a thinner thickness than when PtMn is used as the pinning layer 206. In this case, the thickness of the pinning layer 206 is preferably 4 nm or more and 18 nm or less. The thickness of the pinning layer 206 is more preferably 5 nm or more and 15 nm or less. For the pinning layer 206, for example, a 7 nm thick Ir ₂₂ Mn ₇₈ layer is used.

A hard magnetic layer may be used as the pinning layer 206. As the hard magnetic layer, for example, Co-Pt, Fe-Pt, Co-Pd, or Fe-Pd may be used. In these materials, for example, magnetic anisotropy and coercivity are relatively high. These materials are hard magnetic materials. As the pinning layer 206, Co-Pt, Fe-Pt, Co-Pd, or an alloy obtained by adding an additional element to Fe-Pd may be used. For example, CoPt (ratio of Co is 50at.% Or more 85 at.% Or _{less), (Co x Pt 100-} x) 100-y Cr y (x is a 50at.% Or more 85 at.% Or less, y is, 0 at.% Or more and 40 at.% Or less, FePt (the ratio of Pt is 40 at.% Or more and 60 at.% Or less), or the like may be used.

For the second magnetization fixed layer 207, for example, a Co _x Fe _100-x alloy (x is 0 at.% Or more and 100 at.% Or less) or a Ni _x Fe _100-x alloy (x is 0 at.% Or more and 100 at. .% Or less) is used. Materials obtained by adding nonmagnetic elements to these materials may be used. As the second magnetization fixed layer 207, for example, at least one selected from the group consisting of Co, Fe, and Ni is used. As the second magnetization fixed layer 207, an alloy containing at least one material selected from these materials may be used. The second magnetization pinned layer _207, a _{(Co x Fe 100-x)} 100-y B y alloys (x is, 0 atomic.% Or more 100at is at.% Or less, y is, 0 atomic.% Or more 30 at.% Or less) It can also be used. The second magnetization pinned layer _{207, (Co x Fe 100-} x) by using a _{100-y B y} of the amorphous alloy, even when the size of the sensing element is small, to suppress the variation in characteristics of the sensing element 50A Can.

  The thickness of the second magnetization fixed layer 207 is preferably, for example, 1.5 nm or more and 5 nm or less. Thereby, for example, the strength of the unidirectional anisotropic magnetic field by the pinning layer 206 can be made stronger. For example, increasing the strength of the antiferromagnetic coupling magnetic field between the second magnetization fixed layer 207 and the first magnetization fixed layer 209 via the magnetic coupling layer formed on the second magnetization fixed layer 207. Can. For example, it is preferable that the magnetic film thickness of the second magnetization fixed layer 207 (product of saturated magnetization Bs and thickness t (Bs · t)) be substantially equal to the magnetic film thickness of the first magnetization fixed layer 209 .

The saturation magnetization of Co ₄₀ Fe ₄₀ B _{20 in} a thin film is about 1.9 T (Tesla). For example, when a 3 nm thick Co ₄₀ Fe ₄₀ B ₂₀ layer is used as the first magnetization fixed layer 209, the magnetic thickness of the first magnetization fixed layer 209 is 1.9 T × 3 nm, 5.7 T nm, Become. On the other hand, the saturation magnetization of Co ₇₅ Fe ₂₅ is about 2.1 T. The thickness of the second magnetization fixed layer 207 at which the magnetic film thickness equal to the above is obtained is 5.7 Tnm / 2.1T, which is 2.7 nm. In this case, as the second magnetization fixed layer 207, it is preferable to use a Co ₇₅ Fe ₂₅ layer having a thickness of about 2.7 nm. As the second magnetization fixed layer 207, for example, a Co ₇₅ Fe ₂₅ layer having a thickness of 2.5 nm is used.

In the sensing element 50A, a synthetic pin structure is used by the second magnetization fixed layer 207, the magnetic coupling layer 208, and the first magnetization fixed layer 209. Instead, a single pin structure of one magnetization fixed layer may be used. When the single pin structure is used, for example, a Co ₄₀ Fe ₄₀ B ₂₀ layer with a thickness of 3 nm is used as the magnetization fixed layer. The same material as the material of the second magnetization fixed layer 207 described above may be used as the ferromagnetic layer used for the magnetization fixed layer of the single pin structure.

  The magnetic coupling layer 208 causes antiferromagnetic coupling between the second magnetization fixed layer 207 and the first magnetization fixed layer 209. The magnetic coupling layer 208 forms a synthetic pin structure. As a material of the magnetic coupling layer 208, for example, Ru is used. The thickness of the magnetic coupling layer 208 is preferably, for example, 0.8 nm or more and 1 nm or less. A material other than Ru may be used as the magnetic coupling layer 208 as long as it is a material that causes sufficient antiferromagnetic coupling between the second magnetization fixed layer 207 and the first magnetization fixed layer 209. The thickness of the magnetic coupling layer 208 is set to, for example, a thickness of 0.8 nm or more and 1 nm or less corresponding to a second peak (2nd peak) of RKKY (Ruderman-Kittel-Kasuya-Yosida) bonding. Furthermore, the thickness of the magnetic coupling layer 208 may be set to a thickness of 0.3 nm or more and 0.6 nm or less corresponding to the first peak (1st peak) of the RKKY bond. As a material of the magnetic coupling layer 208, for example, Ru having a thickness of 0.9 nm is used. Thereby, a reliable connection can be obtained more stably.

The magnetic layer used for the first magnetization fixed layer 209 directly contributes to the MR effect. As the first magnetization fixed layer 209, for example, a Co-Fe-B alloy is used. Specifically, the first magnetization pinned layer _{209, (Co x Fe 100-} x) 100-y B y alloys (x is less than 0 atomic.% Or more 100 atomic.%, Y is 0 atomic.% Or more 30at Or less) can also be used. The first magnetization pinned layer _209, in the case of using the _{(Co x Fe 100-x)} 100-y B y of the amorphous alloy, for example, in a case where the size of the sensing element 50A is smaller, due to the grain element It is possible to suppress the variation between them.

A layer (for example, a tunnel insulating layer (not shown)) formed on the first magnetization fixed layer 209 can be planarized. Planarization of the tunnel insulating layer can reduce the defect density of the tunnel insulating layer. This results in a higher MR ratio with lower areal resistance. For example, in the case of using MgO as a material of the tunnel insulating layer, a first magnetization pinned layer _{209, (Co x Fe 100-} x) by using a _{100-y B y} of the amorphous alloy, on top of the tunnel insulating layer The (100) orientation of the MgO layer to be formed can be intensified. By making the (100) orientation of the MgO layer higher, a larger MR change rate can be obtained. _{(Co x Fe 100-x)} 100-y B y alloys crystallize the MgO layer (100) plane as a template during annealing. Therefore, good crystal matching between MgO and _{(Co x Fe 100-x)} 100-y B y alloys are obtained. By obtaining a good crystal alignment, a larger MR ratio can be obtained.

  As the first magnetization fixed layer 209, for example, an Fe--Co alloy may be used other than the Co--Fe--B alloy.

  When the first magnetization fixed layer 209 is thicker, a larger MR ratio is obtained. If the first magnetization fixed layer 209 is thin, for example, a larger fixed magnetic field can be obtained. There is a trade-off relationship in the thickness of the first magnetization fixed layer 209 between the MR ratio and the fixed magnetic field. When a Co—Fe—B alloy is used as the first magnetization fixed layer 209, the thickness of the first magnetization fixed layer 209 is preferably 1.5 nm or more and 5 nm or less. The thickness of the first magnetization fixed layer 209 is more preferably 2.0 nm or more and 4 nm or less.

For the first magnetization fixed layer 209, in addition to the above-described materials, a Co ₉₀ Fe ₁₀ alloy of fcc structure, Co of hcp structure, or Co alloy of hcp structure is used. As the first magnetization fixed layer 209, for example, at least one selected from the group consisting of Co, Fe, and Ni is used. As the first magnetization fixed layer 209, an alloy containing at least one material selected from these materials is used. By using, as the first magnetization fixed layer 209, a FeCo alloy material of bcc structure, a Co alloy containing 50% or more of cobalt composition, or a material of 50% or more of Ni composition (Ni alloy), for example, a larger MR The rate of change is obtained.

As the first magnetization fixed layer 209, for example, Co ₂ MnGe, Co ₂ FeGe, Co ₂ MnSi, Co ₂ FeSi, Co ₂ MnAl, Co ₂ FeAl, Co ₂ MnGa _0.5 Ge _0.5 , and Co ₂ FeGa A Heusler magnetic alloy layer such as _0.5 Ge _0.5 can also be used. For example, as the first magnetization fixed layer 209, for example, a Co ₄₀ Fe ₄₀ B ₂₀ layer with a thickness of 3 nm is used.

  The intermediate layer 203 breaks the magnetic coupling between the first magnetic layer 10 and the second magnetic layer 20, for example.

  As a material of the intermediate layer 203, for example, a metal, an insulator or a semiconductor is used. As the metal, for example, Cu, Au or Ag is used. When a metal is used as the intermediate layer 203, the thickness of the intermediate layer is, for example, about 1 nm or more and 7 nm or less. As this insulator or semiconductor, for example, magnesium oxide (such as MgO), aluminum oxide (such as Al2O3), titanium oxide (such as TiO), zinc oxide (such as ZnO), or gallium oxide (such as Ga- O) etc. are used. When an insulator or a semiconductor is used as the intermediate layer 203, the thickness of the intermediate layer 203 is, for example, about 0.6 nm or more and 2.5 nm or less. As the intermediate layer 203, for example, a CCP (Current-Confined-Path) spacer layer may be used. When a CCP spacer layer is used as a spacer layer, for example, a structure in which a copper (Cu) metal path is formed in an insulating layer of aluminum oxide (Al2O3) is used. For example, a MgO layer with a thickness of 1.6 nm is used as the intermediate layer.

A ferromagnetic material is used for the magnetization free layer 210. For the magnetization free layer 210, for example, a ferromagnetic material containing Fe, Co, Ni is used. As a material of the magnetization free layer 210, for example, a FeCo alloy, a NiFe alloy or the like is used. Furthermore, in the magnetization free layer 210, a Co-Fe-B alloy, an Fe-Co-Si-B alloy, an Fe-Ga alloy having a large λs (magnetostriction constant), an Fe-Co-Ga alloy, a Tb-M-Fe alloy , Tb-M1-Fe-M2 alloy, Fe-M3-M4-B alloy, Ni, Fe-Al, or ferrite is used. In these materials, for example, λs (magnetostriction constant) is large. In the above-mentioned Tb-M-Fe alloy, M is at least one selected from the group consisting of Sm, Eu, Gd, Dy, Ho and Er. In the above-mentioned Tb-M1-Fe-M2 alloy, M1 is at least one selected from the group consisting of Sm, Eu, Gd, Dy, Ho and Er. M2 is at least one selected from the group consisting of Ti, Cr, Mn, Co, Cu, Nb, Mo, W and Ta. In the above Fe-M3-M4-B alloy, M3 is at least one selected from the group consisting of Ti, Cr, Mn, Co, Cu, Nb, Mo, W and Ta. M4 is at least one selected from the group consisting of Ce, Pr, Nd, Sm, Tb, Dy and Er. Examples of the _ferrite, Fe ₃ O _4, and the like _(FeCo) 3 _{O 4.} The thickness of the magnetization free layer 210 is, for example, 2 nm or more.

The magnetic free layer 210 may be made of a magnetic material containing boron. For the magnetization free layer 210, for example, an alloy containing at least one element selected from the group consisting of Fe, Co and Ni and boron (B) may be used. For the magnetization free layer 210, for example, a Co-Fe-B alloy or an Fe-B alloy is used. For _example, Co _{40 Fe 40 B 20} alloy. When an alloy containing at least one element selected from the group consisting of Fe, Co and Ni and boron (B) is used for the magnetization free layer 210, Ga, Al, Si, or W is added. Also good. The addition of these elements promotes, for example, high magnetostriction. As the magnetization free layer 210, for example, an Fe-Ga-B alloy, a Fe-Co-Ga-B alloy, or an Fe-Co-Si-B alloy may be used. By using such a boron-containing magnetic material, the coercivity (Hc) of the magnetization free layer 210 becomes low, and the change of the magnetization direction with respect to strain becomes easy. This provides high sensitivity.

  The boron concentration (for example, the composition ratio of boron) in the magnetization free layer 210 is 5 at. % (Atomic percent) or more is preferable. This makes it easy to obtain an amorphous structure. The boron concentration in the magnetization free layer is 35 at. % Or less is preferable. If the boron concentration is too high, for example, the magnetostriction constant decreases. The boron concentration in the magnetization free layer is, for example, 5 at. % Or more 35 at. % Or less is preferable, and 10 at. % To 30 at. % Or less is more preferable.

Some of the magnetic layer of the magnetic free layer _{210, Fe 1-y B y} (0 <y ≦ 0.3), or _{(Fe z X 1-a)} 1-y B y (X is, Co or Ni, When 0.8 ≦ z <1, 0 <y ≦ 0.3, it is easy to simultaneously achieve a large magnetostriction constant λ and a low coercivity. For this reason, it is particularly preferable in view of obtaining a high gauge factor. For example, Fe ₈₀ B ₂₀ (4 nm) is used as the magnetization free layer 210. As the magnetization free _{layer, Co 40 Fe 40 B 20 (} 0.5nm) / Fe 80 B 20 (4nm) is used.

  The magnetization free layer 210 may have a multilayer structure. When a tunnel insulating layer of MgO is used as the intermediate layer 203, a layer of a Co-Fe-B alloy is preferably provided in a portion of the magnetization free layer 210 in contact with the intermediate layer 203. Thereby, a high magnetoresistance effect can be obtained. In this case, a layer of a Co-Fe-B alloy is provided on the intermediate layer 203, and another magnetic material having a large magnetostriction constant is provided on the layer of the Co-Fe-B alloy. When the magnetization free layer 210 has a multilayer structure, for example, Co-Fe-B (2 nm) / Fe-Co-Si-B (4 nm) or the like is used for the magnetization free layer 210.

  The cap layer 211 protects a layer provided under the cap layer 211. For the cap layer 211, for example, a plurality of metal layers are used. For the cap layer 211, for example, a two-layer structure (Ta / Ru) of a Ta layer and a Ru layer is used. The thickness of this Ta layer is, for example, 1 nm, and the thickness of this Ru layer is, for example, 5 nm. As the cap layer 211, another metal layer may be provided instead of the Ta layer or the Ru layer. The configuration of the cap layer 211 is arbitrary. For example, a nonmagnetic material is used as the cap layer 211. Other materials may be used as the cap layer 211 as long as the layer provided below the cap layer 211 can be protected.

  When a magnetic material containing boron is used for the magnetization free layer 210, a diffusion suppression layer (not shown) of an oxide material or a nitride material may be provided between the magnetization free layer 210 and the cap layer 211. Thereby, for example, the diffusion of boron is suppressed. By using a diffusion suppression layer including an oxide layer or a nitride layer, diffusion of boron contained in the magnetization free layer 210 can be suppressed, and the amorphous structure of the magnetization free layer 210 can be maintained. As an oxide material or nitride material used for the diffusion suppression layer, for example, Mg, Al, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ru, Rh An oxide material or nitride material containing an element such as Pd, Ag, Hf, Ta, W, Sn, Cd or Ga is used. The diffusion suppression layer is a layer that does not contribute to the magnetoresistance effect. The area resistance of the diffusion suppression layer is preferably low. For example, the area resistance of the diffusion suppression layer is preferably set lower than the area resistance of the intermediate layer contributing to the magnetoresistance effect. From the viewpoint of reducing the area resistance of the diffusion suppression layer, an oxide or a nitride of Mg, Ti, V, Zn, Sn, Cd, or Ga is preferable for the diffusion suppression layer. The barrier height is low in these materials. As a function to suppress the diffusion of boron, an oxide having a stronger chemical bond is preferable. For example, a 1.5 nm MgO layer is used. The oxynitride is contained in either the oxide or the nitride.

  When an oxide or a nitride is used for the diffusion suppression layer, the thickness of the diffusion suppression layer is preferably, for example, 0.5 nm or more. Thus, the diffusion suppressing function of boron is sufficiently exerted. The thickness of the diffusion suppression layer is preferably 5 nm or less. Thereby, for example, low area resistance can be obtained. The thickness of the diffusion suppression layer is preferably 0.5 nm or more and 5 nm or less, and more preferably 1 nm or more and 3 nm or less.

  As the diffusion suppression layer, at least one selected from the group consisting of magnesium (Mg), silicon (Si) and aluminum (Al) may be used. A material containing these light elements is used as the diffusion suppression layer. These light elements combine with boron to form a compound. For example, at least one of a Mg-B compound, an Al-B compound, and a Si-B compound is formed in a portion including the interface between the diffusion suppression layer and the magnetization free layer 210. These compounds suppress the diffusion of boron.

  Another metal layer or the like may be inserted between the diffusion suppression layer and the magnetization free layer 210. If the distance between the diffusion suppression layer and the magnetization free layer 210 is too large, boron diffuses between them and the boron concentration in the magnetization free layer 210 decreases. Therefore, the distance between the diffusion suppression layer and the magnetization free layer 210 is preferably 10 nm or less, and more preferably 3 nm or less.

FIG. 8 is a schematic perspective view illustrating a portion of another pressure sensor according to the embodiment.
As shown in FIG. 8, the sensing element 50AA is the same as the sensing element 50A except that the insulating layer 213 is provided. The insulating layer 213 is provided between the lower electrode 204 and the upper electrode 212. The insulating layer 213 is aligned with the magnetization free layer 210 and the first magnetization fixed layer 209 in a direction intersecting the direction connecting the lower electrode 204 and the upper electrode 212. The portions other than the insulating layer 213 are the same as those of the detection element 50A, and thus the description thereof is omitted.

For the insulating layer 213, for example, aluminum oxide (for example, Al ₂ O ₃ ), silicon oxide (for example, SiO ₂ ), or the like is used. The insulating layer 213 suppresses the leak current of the sensing element 50AA. The insulating layer 213 may be provided in a detection element described later.

FIG. 9 is a schematic perspective view illustrating a portion of another pressure sensor according to the embodiment.
As shown in FIG. 9, a hard bias layer 214 is further provided in the sensing element 50AB. Except this, it is the same as that of sensing element 50A. The hard bias layer 214 is provided between the lower electrode 204 and the upper electrode 212. The magnetization free layer 210 and the first magnetization fixed layer 209 are disposed between two portions of the hard bias layer 214 in a direction intersecting the direction connecting the lower electrode 204 and the upper electrode 212. Except this, it is the same as that of sensing element 50AA.

  The hard bias layer 214 sets the magnetization direction of the magnetization free layer 210 by the magnetization of the hard bias layer 214. With the hard bias layer 214, the magnetization direction of the magnetization free layer 210 is set to a desired direction in a state where no external pressure is applied to the film portion 70d.

For the hard bias layer 214, for example, Co-Pt, Fe-Pt, Co-Pd, or Fe-Pd is used. In these materials, for example, magnetic anisotropy and coercivity are relatively high. These materials are, for example, hard magnetic materials. For the hard bias layer 214, for example, an alloy in which an additive element is further added to Co-Pt, Fe-Pt, Co-Pd, or Fe-Pd may be used. The hard bias layers 214, for example, CoPt (ratio of Co is, 50at.% Or more 85 at.% Or _{less), (Co x Pt 100-} x) 100-y Cr y (x is 50at.% Or more 85 at.% Or less Y may be 0 at.% Or more and 40 at.% Or less, FePt (the ratio of Pt is 40 at.% Or more and 60 at.% Or less), or the like may be used. When such a material is used, the direction of magnetization of the hard bias layer 214 is set (fixed) in the direction in which the external magnetic field is applied by applying an external magnetic field larger than the coercivity of the hard bias layer 214. The thickness (for example, the length along the direction from the lower electrode 204 toward the upper electrode) of the hard bias layer 214 is, for example, 5 nm or more and 50 nm or less.

When the insulating layer 213 is disposed between the lower electrode 204 and the upper electrode 212, SiO _x or AlO _x is used as a material of the insulating layer 213. Further, an underlayer (not shown) may be provided between the insulating layer 213 and the hard bias layer 214. When a hard magnetic material such as Co-Pt, Fe-Pt, Co-Pd, or Fe-Pd is used for the hard bias layer 214, Cr or Fe-Co is used as a material of the underlayer for the hard bias layer 214. Etc. are used.

The hard bias layer 214 may have a structure stacked on a hard bias layer pinning layer (not shown). In this case, the magnetization direction of the hard bias layer 214 can be set (fixed) by exchange coupling between the hard bias layer 214 and the pinning layer for hard bias layer. In this case, the hard bias layer 214 is made of a ferromagnetic material of an alloy containing at least one of Fe, Co and Ni, or at least one of them. In this case, the hard bias layer 214 may be, for example, a Co _x Fe _100-x alloy (x is 0 at.% Or more and 100 at.% Or less), a Ni _x Fe _100-x alloy (x is 0 at.% Or more and 100 at. Or materials obtained by adding a nonmagnetic element thereto are used. As the hard bias layer 214, the same material as that of the first magnetization fixed layer 209 described above is used. For the hard bias layer pinning layer, the same material as the pinning layer 206 in the above-mentioned sensing element 50A is used. In the case of providing a hard bias layer pinning layer, an underlayer similar to the material used for the underlayer 205 may be provided below the hard bias layer pinning layer. The hard bias layer pinning layer may be provided below or above the hard bias layer. The magnetization direction of the hard bias layer 214 in this case, like the pinning layer 206, is determined by heat treatment in a magnetic field.

  The hard bias layer 214 and the insulating layer 213 described above can be applied to any of the sensing elements according to the embodiment. When the stacked structure of the hard bias layer 214 and the hard bias layer pinning layer is used, the magnetization direction of the hard bias layer 214 is easily maintained even when a large external magnetic field is applied to the hard bias layer 214 in a short time. be able to.

FIG. 10 is a schematic perspective view illustrating a portion of another pressure sensor according to the embodiment.
As shown in FIG. 10, in the sensing element 50B, the lower electrode 204, the underlayer 205, the magnetization free layer 210, the intermediate layer 203, the first magnetization fixed layer 209, the magnetic coupling layer 208, and the second magnetization. The fixed layer 207, the pinning layer 206, the cap layer 211, and the upper electrode 212 are sequentially stacked. The first magnetization fixed layer 209 corresponds to the second magnetic layer 20. The magnetization free layer 210 corresponds to the first magnetic layer 10. The sensing element 50B is, for example, a top spin valve type.

As the base layer 205, for example, a laminated film (Ta / Cu) of tantalum and copper is used. The thickness (length in the Z-axis direction) of this Ta layer is, for example, 3 nm. The thickness of this Cu layer is, for example, 5 nm. For the magnetization free layer 210, for example, Co ₄₀ Fe ₄₀ B ₂₀ having a thickness of 4 nm is used. For the intermediate layer 203, for example, an MgO layer having a thickness of 1.6 nm is used. The first magnetization fixing layer 209, for _{example, Co 40 Fe 40 B 20 /} Fe 50 Co 50 is used. The thickness of this Co ₄₀ Fe ₄₀ B ₂₀ layer is, for example, 2 nm. The thickness of this Fe ₅₀ Co ₅₀ layer is, for example, 1 nm. For the magnetic coupling layer 208, for example, a Ru layer with a thickness of 0.9 nm is used. For the second magnetization fixed layer 207, for example, a Co ₇₅ Fe ₂₅ layer with a thickness of 2.5 nm is used. For the pinning layer 206, for example, an IrMn layer with a thickness of 7 nm is used. For the cap layer 211, for example, Ta / Ru is used. The thickness of this Ta layer is, for example, 1 nm. The thickness of this Ru layer is, for example, 5 nm.

  The material of each layer included in the sensing element 50B can be used by inverting the material of each layer included in the sensing element 50A up and down. The above-described diffusion suppression layer may be provided between the underlayer 205 of the sensing element 50B and the magnetization free layer 210.

FIG. 11 is a schematic perspective view illustrating a portion of another pressure sensor according to the embodiment.
As shown in FIG. 11, in the sensing element 50C, the lower electrode 204, the base layer 205, the pinning layer 206, the first magnetization fixed layer 209, the intermediate layer 203, the magnetization free layer 210, and the cap layer 211. , Are stacked in this order. The first magnetization fixed layer 209 corresponds to the second magnetic layer 20. The magnetization free layer 210 corresponds to the first magnetic layer 10. The sensing element 50C has, for example, a single pin structure using a single magnetization fixed layer.

For the base layer 205, for example, Ta / Ru is used. The thickness (length in the Z-axis direction) of this Ta layer is, for example, 3 nm. The thickness of this Ru layer is, for example, 2 nm. For the pinning layer 206, for example, an IrMn layer with a thickness of 7 nm is used. For the first magnetization fixed layer 209, for example, a Co ₄₀ Fe ₄₀ B ₂₀ layer with a thickness of 3 nm is used. For the intermediate layer 203, for example, an MgO layer having a thickness of 1.6 nm is used. For the magnetization free layer 210, for example, Co ₄₀ Fe ₄₀ B ₂₀ having a thickness of 4 nm is used. For the cap layer 211, for example, Ta / Ru is used. The thickness of this Ta layer is, for example, 1 nm. The thickness of this Ru layer is, for example, 5 nm.

  As the material of each layer of the sensing element 50C, for example, the same material as the material of each layer of the sensing element 50A is used.

FIG. 12 is a schematic perspective view illustrating a part of another pressure sensor according to the embodiment.
As shown in FIG. 12, in the sensing element 50D, the lower electrode 204, the underlayer 205, the lower pinning layer 221, the lower second magnetization fixed layer 222, the lower magnetic coupling layer 223, and the lower first magnetization fixed layer 224, lower intermediate layer 225, magnetization free layer 226, upper intermediate layer 227, upper first magnetization fixed layer 228, upper magnetic coupling layer 229, upper second magnetization fixed layer 230, upper pinning layer 231 And the cap layer 211 are sequentially stacked. The lower first magnetization fixed layer 224 and the upper first magnetization fixed layer 228 correspond to, for example, the second magnetic layer 20. The magnetization free layer 226 corresponds to, for example, the first magnetic layer 10.

For the base layer 205, for example, Ta / Ru is used. The thickness (length in the Z-axis direction) of this Ta layer is, for example, 3 nanometers (nm). The thickness of this Ru layer is, for example, 2 nm. For the lower pinning layer 221, for example, an IrMn layer with a thickness of 7 nm is used. For the lower second magnetization fixed layer 222, for example, a Co ₇₅ Fe ₂₅ layer with a thickness of 2.5 nm is used. For the lower magnetic coupling layer 223, for example, a Ru layer with a thickness of 0.9 nm is used. For the lower first magnetization fixed layer 224, for example, a Co ₄₀ Fe ₄₀ B ₂₀ layer with a thickness of 3 nm is used. For the lower intermediate layer 225, for example, an MgO layer having a thickness of 1.6 nm is used. The magnetization free layer 226, for example, _Co 40 _Fe 40 _{B 20} having a thickness of 4nm is used. For the upper intermediate layer 227, for example, an MgO layer having a thickness of 1.6 nm is used. The top to the first magnetization pinned layer 228, for _{example, Co 40 Fe 40 B 20 /} Fe 50 Co 50 is used. The thickness of this Co ₄₀ Fe ₄₀ B ₂₀ layer is, for example, 2 nm. The thickness of this Fe ₅₀ Co ₅₀ layer is, for example, 1 nm. For the upper magnetic coupling layer 229, for example, a Ru layer with a thickness of 0.9 nm is used. For the upper second magnetization fixed layer 230, for example, a Co ₇₅ Fe ₂₅ layer with a thickness of 2.5 nm is used. For the upper pinning layer 231, for example, an IrMn layer with a thickness of 7 nm is used. For the cap layer 211, for example, Ta / Ru is used. The thickness of this Ta layer is, for example, 1 nm. The thickness of this Ru layer is, for example, 5 nm.

  As a material of each layer of sensing element 50D, the thing similar to the material of each layer of sensing element 50A is used, for example.

FIG. 13 is a schematic perspective view illustrating a part of another pressure sensor according to the embodiment.
As shown in FIG. 13, in the sensing element 50E, the lower electrode 204, the underlayer 205, the first magnetization free layer 241, the intermediate layer 203, the second magnetization free layer 242, the cap layer 211, and the upper electrode And 212 are stacked in this order. The first magnetization free layer 241 corresponds to the first magnetic layer 10. The second magnetization free layer 242 corresponds to the second magnetic layer 20. In this example, the magnetization of the second magnetic layer 20 can be changed.

For the base layer 205, for example, Ta / Cu is used. The thickness (length in the Z-axis direction) of this Ta layer is, for example, 3 nm. The thickness of this Cu layer is, for example, 5 nm. The first magnetization free layer 241, for example, _Co 40 _Fe 40 _{B 20} having a thickness of 4nm is used. For example, Co ₄₀ Fe ₄₀ B ₂₀ having a thickness of 4 nm is used for the intermediate layer 203 in Example 2. For example, Cu / Ta / Ru is used for the cap layer 211. The thickness of this Cu layer is, for example, 5 nm. The thickness of this Ta layer is, for example, 1 nm. The thickness of this Ru layer is, for example, 5 nm.

  The material of each layer of the sensing element 50E is the same as the material of each layer of the sensing element 50A. As a material of the first magnetization free layer 241 and the second magnetization free layer 242, for example, the same material as the magnetization free layer 210 of the sensing element 50A may be used.

Third Embodiment
FIG. 14 is a schematic view illustrating a microphone according to the third embodiment.
As shown in FIG. 14, the microphone 610 according to the present embodiment includes any pressure sensor according to the above embodiment or a pressure sensor according to a modification thereof. In this example, a pressure sensor 110 is used as a pressure sensor.

  The microphone 610 is provided, for example, in the portable information terminal 710. The film unit 70 d of the pressure sensor 110 is, for example, substantially parallel to the surface of the portable information terminal 710 on which the display unit 620 is provided. The arrangement of the film unit 70d is arbitrary. According to the embodiment, it is possible to provide a microphone whose dynamic range can be expanded. The microphone 610 according to the embodiment may be provided, for example, in an IC recorder or a pin microphone.

  FIG. 15 is a schematic cross-sectional view illustrating another microphone according to the third embodiment. A microphone 320 (acoustic microphone) according to the present embodiment includes a printed circuit board 321, a cover 323, and a pressure sensor. As a pressure sensor, any of the pressure sensors according to the embodiments or their variants are used. In this example, a pressure sensor 110 is used as a pressure sensor. The printed circuit board 321 includes, for example, a circuit such as an amplifier. The cover 323 is provided with an acoustic hole 325. The sound 329 enters the inside of the cover 323 through the acoustic hole 325. The microphone 320 is sensitive to sound pressure. By using the highly sensitive pressure sensor 110, a highly sensitive microphone 320 can be obtained. For example, the pressure sensor 110 is mounted on the printed circuit board 321, and an electrical signal line is provided. A cover 323 is provided on the printed circuit board 321 so as to cover the pressure sensor 110. It is possible to provide a microphone whose dynamic range can be expanded.

Fourth Embodiment
FIGS. 16A and 16B are schematic views illustrating the blood pressure sensor according to the fourth embodiment.
FIG. 16 (a) is a schematic plan view illustrating the skin on human arterial blood vessels. FIG. 16 (b) is a cross-sectional view taken along line H <b> 1-H <b> 2 of FIG.

  The blood pressure sensor 330 according to this embodiment includes any pressure sensor according to the embodiment or a variation thereof. In this example, a pressure sensor 110 is used as a pressure sensor. Pressure sensor 110 is pressed against skin 333 above arterial blood vessel 331. Thereby, the blood pressure sensor 330 can perform blood pressure measurement continuously. According to the present embodiment, it is possible to provide a blood pressure sensor capable of expanding the dynamic range. Blood pressure can be measured with high sensitivity.

Fifth Embodiment
FIG. 17 is a schematic view illustrating the touch panel according to the fifth embodiment.
As the touch panel 340 according to the present embodiment, any pressure sensor according to the embodiment or a modification thereof is used. In this example, a pressure sensor 110 is used as a pressure sensor. In the touch panel 340, the pressure sensor 110 is mounted on at least one of the inside of the display and the outside of the display.

  For example, the touch panel 340 includes a plurality of first wires 346, a plurality of second wires 347, a plurality of pressure sensors 110, and a control unit 341.

  In this example, the plurality of first wires 346 are arranged along the Y-axis direction. Each of the plurality of first wires 346 extends along the X-axis direction. The plurality of second wires 347 are arranged along the X-axis direction. Each of the plurality of second wires 347 extends along the Y-axis direction.

  Each of the plurality of pressure sensors 110 is provided at each intersection of the plurality of first wires 346 and the plurality of second wires 347. One of the pressure sensors 110 is one of the sensing elements 310 e for sensing. Here, the intersection includes a position where the first wire 346 and the second wire 347 intersect and a region around the position.

  One end 310 a of each of the plurality of pressure sensors 110 is connected to each of the plurality of first wires 346. The other end 310 b of each of the plurality of pressure sensors 110 is connected to each of the plurality of second wires 347.

  The control unit 341 is connected to the plurality of first wires 346 and the plurality of second wires 347. For example, the control unit 341 includes a first wiring circuit 346d connected to the plurality of first wirings 346, a second wiring circuit 347d connected to the plurality of second wirings 347, and a first wiring circuit 346d. And a control circuit 345 connected to the second wiring circuit 347d. The pressure sensor 110 is capable of compact and highly sensitive pressure sensing. Therefore, it is possible to realize a high definition touch panel.

  According to the embodiment, it is possible to provide a touch panel whose dynamic range can be expanded. Enables highly sensitive touch input.

  The pressure sensor according to the embodiment may be applied to an air pressure sensor, a tire air pressure sensor, or the like in addition to the application described above. The pressure sensor according to the embodiment can be applied to various pressure detections.

  According to the embodiment, it is possible to provide a pressure sensor, a microphone, a blood pressure sensor, and a touch panel whose dynamic range can be expanded.

  In an embodiment, the pressure sensor is, for example, a balanced pressure sensor. The pressure sensor includes, for example, a support, a substrate, a sensing element, and a magnetic field generator. The substrate is supported by the support and converts the measured pressure into strain. The substrate is flexible. The sensing element is formed on a substrate. The sensing element causes a change in resistance due to a change in strain. The sensing element includes a first magnetic layer whose magnetization changes due to strain, a second magnetic layer, and a spacer layer formed between the first and second magnetic layers. The magnetic field generator applies a magnetic field to the sensing element. The magnetic field generation unit changes the magnetization of the first magnetic layer. In the pressure sensor, a current corresponding to the change in resistance flows in the magnetic field generation unit. For example, the current flowing to the magnetic field generation unit is obtained when an equilibrium state is reached in which the change in magnetization of the first magnetic layer due to strain and the change in magnetization of the first magnetic layer due to the magnetic field cancel each other. This current measures the pressure to be detected. In the present embodiment, a feedback circuit is provided. The feedback circuit senses a change in resistance of the sensing element and applies an appropriate current to the magnetic field generator. As a magnetic field which balances the resistance of the sensing element, an induced magnetic field generated from a lead placed near the sensing element is used.

(Supplementary note)
Embodiments include the following features.
(Feature 1)
A deformable membrane portion,
A sensing element fixed to a part of the film portion and including a first magnetic layer, a second magnetic layer, and an intermediate layer provided between the first magnetic layer and the second magnetic layer;
A magnetic field generation unit that applies a magnetic field to the detection element;
Pressure sensor with.

(Feature 2)
The membrane portion has an outer edge including a first side extending in a first direction,
The sensing element is closest to the first side of the outer edge,
A pressure sensor according to Feature 1, wherein the magnetic field comprises a component in a second direction perpendicular to the first direction.

(Feature 3)
The membrane portion has an outer edge,
The sensing element is closest to a first outer edge portion of the outer edge,
The magnetic field generation unit includes a wire,
The wire has an extending portion along the first outer edge portion,
A pressure sensor according to Feature 1, wherein the sensing element is disposed between the extension portion and the membrane portion.

(Feature 4)
The membrane portion has an outer edge including a first side extending in a first direction,
The sensing element is closest to the first side of the outer edge,
The magnetic field generation unit includes a wire,
The wire has an extending portion extending in a first direction,
A pressure sensor according to Feature 1, wherein the sensing element is disposed between the extension portion and the membrane portion.

(Feature 5)
The outer edge is separated from the first side in a second direction intersecting the first direction and extends in the first direction, a third side extending in the second direction, and the third side in the first direction. And a fourth side separated from the third side and extending in the second direction, and a length along the first direction between the third side and the fourth side is the first side A pressure sensor according to Feature 4, wherein the pressure sensor is longer than the length along the second direction between the second side.

(Feature 6)
The membrane portion has an outer edge,
The sensing element is closest to a first outer edge portion of the outer edge,
The magnetic field generator includes a coil,
The pressure sensor according to Feature 1, wherein an axis of winding of the coil intersects with an extending direction of the first outer edge portion.

(Feature 7)
The membrane portion has an outer edge including a first side extending in a first direction,
The sensing element is closest to the first side of the outer edge,
The magnetic field generator includes a coil,
The pressure sensor according to Feature 1, wherein an axis of winding of the coil intersects the first direction.

(Feature 8)
The outer edge is separated from the first side in a second direction intersecting the first direction and extends in the first direction, a third side extending in the second direction, and the third side in the first direction. And a fourth side separated from the third side and extending in the second direction, and a length along the first direction between the third side and the fourth side is the first side A pressure sensor according to Feature 7, wherein the pressure sensor is longer than the length along the second direction between the second side.

(Feature 9)
And a holding unit for holding the outer edge of the membrane unit,
The pressure sensor according to any one of features 6 to 8, wherein the coil is provided in the holding unit.

(Feature 10)
A first circuit electrically connected to one of the first magnetic layer and the second magnetic layer to supply a second current corresponding to a first current flowing to the sensing element to the magnetic field generation unit;
A second circuit electrically connected to the magnetic field generation unit and monitoring the second current;
The pressure sensor according to any one of Features 1 to 9, further comprising a circuit unit including:

(Feature 11)
A deformable membrane portion,
A sensing element fixed to a part of the film portion and including a first magnetic layer, a second magnetic layer, and an intermediate layer provided between the first magnetic layer and the second magnetic layer;
Wiring and
Equipped with
The membrane portion has an outer edge,
The sensing element is closest to a first outer edge portion of the outer edge,
The wire has an extending portion along the first outer edge portion,
The pressure sensor, wherein the sensing element is disposed between the extension portion and the membrane portion.

(Feature 12)
The first outer edge portion includes a first side extending in a first direction,
The sensing element is closest to the first side of the outer edge,
The pressure sensor according to Feature 11, wherein the extension portion extends in a first direction.

(Feature 13)
The outer edge is separated from the first side in a second direction intersecting the first direction and extends in the first direction, a third side extending in the second direction, and the third side in the first direction. And a fourth side separated from the third side and extending in the second direction, and a length along the first direction between the third side and the fourth side is the first side A pressure sensor according to feature 12, wherein a length along the second direction between the second side and the second side is longer.

(Feature 14)
A pressure sensor according to any one of features 12 or 13, wherein the wiring applies a magnetic field to the sensing element.

(Feature 15)
A pressure sensor according to feature 14, wherein the magnetic field comprises a component in a second direction perpendicular to the first direction.

(Feature 16)
A first circuit electrically connected to one of the first magnetic layer and the second magnetic layer to supply a second current to the wiring according to a first current flowing to the sensing element;
A second circuit electrically connected to the wiring and monitoring the second current;
The pressure sensor according to any one of Features 11 to 15, further comprising a circuit unit including:

(Feature 17)
A deformable membrane portion,
A sensing element fixed to a part of the film portion and including a first magnetic layer, a second magnetic layer, and an intermediate layer provided between the first magnetic layer and the second magnetic layer;
With the coil,
Equipped with
The membrane portion has an outer edge,
The sensing element is closest to a first outer edge portion of the outer edge,
A pressure sensor, wherein an axis of winding of the coil intersects with an extension direction of the first outer edge portion.

(Feature 18)
The first outer edge portion includes a first side extending in a first direction,
The sensing element is closest to the first side of the outer edge,
A pressure sensor according to feature 17, wherein the axis intersects the first direction.

(Feature 19)
The outer edge is separated from the first side in a second direction intersecting the first direction and extends in the first direction, a third side extending in the second direction, and the third side in the first direction. And a fourth side separated from the third side and extending in the second direction, and a length along the first direction between the third side and the fourth side is the first side A pressure sensor according to feature 18, wherein the pressure sensor is longer than a length along the second direction between the second side.

(Feature 20)
And a holding unit for holding the outer edge of the membrane unit,
The pressure sensor according to any one of the features 17 to 19, wherein the coil is provided in the holding unit.

(Feature 21)
A pressure sensor according to any one of features 19 or 20, wherein the coil applies a magnetic field to the sensing element.

(Feature 22)
A pressure sensor according to feature 21, wherein the magnetic field comprises a component in a second direction perpendicular to the first direction.

(Feature 23)
A first circuit electrically connected to one of the first magnetic layer and the second magnetic layer to supply a second current to the coil according to a first current flowing to the sensing element;
A second circuit electrically connected to the coil and monitoring the second current;
The pressure sensor according to any one of the features 17 to 22, further comprising a circuit unit including:

(Feature 24)
The pressure sensor according to any one of Features 1 to 23, wherein the magnetization of the first magnetic layer changes in accordance with the deformation of the film portion.

(Feature 25)
A microphone comprising the pressure sensor according to any one of the features 1 to 24.

(Feature 26)
A blood pressure sensor comprising the pressure sensor according to any one of features 1 to 24.

(Feature 27)
The touch panel provided with the pressure sensor as described in any one of the features 1-24.

  In the present specification, "vertical" and "parallel" include not only strictly vertical and strictly parallel but also include, for example, variations in manufacturing processes, etc., and they may be substantially vertical and substantially parallel. Just do it.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, the specific configuration of each element such as a film unit, a sensing element, a magnetic layer, an intermediate layer, an electrode, a magnetic field generation unit, a wiring, a coil, and a circuit included in a pressure sensor is known to those skilled in the art. The present invention is similarly embodied by appropriately selecting from the above, and is included in the scope of the present invention as long as similar effects can be obtained.

  Moreover, what combined any two or more elements of each specific example in the technically possible range is also included in the scope of the present invention as long as the gist of the present invention is included.

  In addition, all pressure sensors, microphones, blood pressure sensors and touch panels that can be appropriately designed and implemented based on the pressure sensors, microphones, blood pressure sensors and touch panels described above as the embodiments of the present invention As long as the scope of the invention is included, it belongs to the scope of the present invention.

  Besides, within the scope of the concept of the present invention, those skilled in the art can conceive of various changes and modifications, and it is understood that the changes and modifications are also within the scope of the present invention. .

  While certain embodiments of the present invention have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

  DESCRIPTION OF SYMBOLS 10 ... 1st magnetic layer, 10b ... 3rd magnetic layer, 10c ... 5th magnetic layer, 10d ... 7th magnetic layer, 20 ... 2nd magnetic layer, 20b ... 4th magnetic layer, 20c ... 6th magnetic layer, 20d Eighth magnetic layer 30 Intermediate layer (first intermediate layer) 30b Second intermediate layer 30c Third intermediate layer 30d Fourth intermediate layer 50, 50A, 50AA, 50AB, 50AC, 50B, 50C, 50D, 50E ... sensing elements, 50a to 50d ... first to fourth sensing elements, 50u ... sensing sections, 58a, 58b ... first and second electrodes, 58c ... insulating film, 60 ... magnetic field generating section, 65, 65A ... wiring 65e ... one end, 65f ... the other end, 65p ... extending part, 66, 66A ... coil, 66x ... axis, 68 ... circuit section, 68a ... first circuit, 68b ... second circuit, 68c ... resistance section , 68d ... power supply unit 70d film portion 70h cavity 70r1 first outer edge portion 70s holding portion 70s1 to s4 1st to 4th sides ε: strain ε1 to ε3 1st to 3rd strain region εA: First strain, ε B second strain 110, 120 pressure sensor 203 intermediate layer 204 lower electrode 205 underlying layer 206 pinning layer 207 second magnetization fixed layer 208 magnetic coupling layer , 209: first magnetization fixed layer, 210: magnetization free layer, 211, cap layer, 212, upper electrode, 213, insulating layer, 214, hard bias layer, 221, lower pinning layer, 222, lower second magnetization fixed layer Lower magnetic coupling layer 223 Lower first magnetization fixed layer 225 Lower intermediate layer 226 Magnetization free layer 227 Upper intermediate layer 228 Upper first magnetization fixed layer 229 Upper magnetic coupling layer 230 Upper second magnetization fixed layer 231 Upper pinning layer 241 First magnetization free layer 242 Second magnetization free layer 310 a One end 310 b Other end 310 e Detection element , 320: microphone, 321: printed circuit board, 323: cover, 325: acoustic hole, 329: sound, 330: blood pressure sensor, 331: arterial blood vessel, 333: skin, 340: touch panel, 341: control unit, 345: control circuit 346 ... 1st wiring, 346d ... 1st wiring circuit, 347 ... 2nd wiring, 347d ... 2nd wiring circuit, 610 ... microphone, 620 ... display unit, 710 ... portable information terminal, AR ... arrow, DR ... Dynamic range, H1 to H3, Ha: magnetic field, I1, I2: first, second current, I ... current, R ... resistors, R1, R2 ... first, second resistor, ST1, ST2 ... first, second state

Claims (13)

A deformable membrane portion,
A sensing element fixed to a part of the film portion and including a first magnetic layer, a second magnetic layer, and an intermediate layer provided between the first magnetic layer and the second magnetic layer;
A magnetic field generator including a wire separated from the sensing element via an air gap and applying a magnetic field to the sensing element;
Sensor with. A deformable membrane portion,
A sensing element fixed to a part of the film portion and including a first magnetic layer, a second magnetic layer, and an intermediate layer provided between the first magnetic layer and the second magnetic layer;
A magnetic field generation unit that includes a wire separated from the film unit and applies a magnetic field to the detection element;
Sensor with. The membrane portion has an outer edge including a first side extending in a first direction,
The sensing element is closest to the first side of the outer edge,
The magnetic field, comprising said second direction component perpendicular to the first direction, the sensor according to claim 1 or 2. The membrane portion has an outer edge,
The sensing element is closest to a first outer edge portion of the outer edge,
The wire has an extending portion along the first outer edge portion,
The sensor according to claim 1, wherein the sensing element is disposed between the extension portion and the membrane portion. The membrane portion has an outer edge including a first side extending in a first direction,
The sensing element is closest to the first side of the outer edge,
The wire has an extending portion extending in a first direction,
The sensor according to claim 1, wherein the sensing element is disposed between the extension portion and the membrane portion. The outer edge is separated from the first side in a second direction intersecting the first direction and extends in the first direction, a third side extending in the second direction, and the third side in the first direction. And a fourth side separated from the third side and extending in the second direction, and a distance between the third side and the fourth side along the first direction is the first side and the fourth side. The sensor according to claim 5 , wherein the distance between the second side and the second side is longer than the distance along the second direction. A first circuit electrically connected to one of the first magnetic layer and the second magnetic layer to supply a second current corresponding to a first current flowing to the sensing element to the magnetic field generation unit;
A second circuit electrically connected to the magnetic field generation unit and monitoring the second current;
The sensor according to any one of claims 1 to 6 , further comprising a circuit unit including A deformable membrane portion,
A sensing element fixed to a part of the film portion and including a first magnetic layer, a second magnetic layer, and an intermediate layer provided between the first magnetic layer and the second magnetic layer;
A magnetic field generation unit that applies a magnetic field to the detection element;
The circuit section,
A first circuit electrically connected to one of the first magnetic layer and the second magnetic layer to supply a second current corresponding to a first current flowing to the sensing element to the magnetic field generation unit;
A second circuit electrically connected to the magnetic field generation unit and monitoring the second current;
The circuit unit including
Equipped with a sensor. A substrate,
With a cover,
And further
The sensor according to any one of claims 1 to 8 , wherein the sensing element is disposed between the substrate and the cover. An information terminal having a sensor according to any one of claims 1-9. A microphone comprising the sensor according to any one of claims 1 to 9 . A blood pressure sensor comprising the sensor according to any one of claims 1 to 9 . A touch panel comprising the sensor according to any one of claims 1 to 9 .

Images