Pressure sensor device

• US 9,618,411 B2
• Filed: 01/24/2013
• Issued: 04/11/2017
• Est. Priority Date: 09/10/2012
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Yuasa, Hiromi, Fukuzawa, Hideaki, Fuji, Yoshihiko, Hara, Michiko, Higashi, Yoshihiro, Nagata, Tomohiko, Hori, Akio
• Primary Examiner(s): Huber, Robert
• Assistant Examiner(s): Roberts, Herbert K
• Application Number:
  US13/749,404
• Publication Number:
  US 20140069200A1
• Time in Patent Office: 1,538 Days
• CPC Class Codes: G01L 1/125 by using magnetostrictive means magnetostrictive sensors H10N35/101
• CPC Class Codes: G01L 9/0051 using variations in ohmic resistance
• CPC Class Codes: G01L 9/16 by making use of variations in the magnetic properties of material resulting from the application of stress
• CPC Class Codes: H10N 35/101 with mechanical input and electrical output, e.g. generators, sensors

Abstract

A pressure sensor device comprises a support substrate including a thin film area which is bendable by a pressure, a sensor film comprising a first electrode provided on the thin film area, a second electrode provided on the first electrode, a reference layer provided between the first electrode and the second electrode, a free layer provided between the reference layer and the first electrode or between the reference layer and the second electrode, a spacer layer provided between the reference layer and the free layer, a shield provided on a side of the support substrate.

Claims

1. A pressure sensor device comprising:

a thin film bendable by a pressure;

a support which fixes the thin film and has a thickness larger than a thickness of the thin film;

a sensor on the thin film, the sensor comprising;

a first electrode on the thin film,

a second electrode,

a reference layer between the first electrode and the second electrode,

a free layer between the reference layer and the first electrode or between the reference layer and the second electrode, and

a spacer layer between the reference layer and the free layer,

wherein the magnetization of the free layer is changeable when the thin film is bent; and

a shield on the support, the shield comprising a soft magnetic material,

wherein the sensor is arranged between a first part of the shield and a second part of the shield in a first direction, the first direction extending along a wider surface of the thin film, and wherein the soft magnetic material of the shield is formed entirely outside the thin film such that the soft magnetic material of the shield does not overlap the thin film in a direction perpendicular to the wider surface of the thin film.

2. The device of claim 1, wherein a material of the thin film is different from a material of the support.

3. The device of claim 1, wherein the first electrode and the second electrode comprise a soft magnetic material.

4. The device of claim 1, wherein an absolute value of a magnetostrictive constant of the free layer is larger than an absolute value of a magnetostrictive constant of each of the shield, the first electrode, and the second electrode.

5. The device of claim 1, wherein the shield comprises NiFe alloy, NiFeX alloy (X is Cu, Cr, Ta, Rh, Pt, or Nb), CoZrNb alloy, or FeAlSi alloy.

6. The device of claim 1, wherein a thickness of the shield is greater than a distance from a top of the sensor, when the thin film is bent, to a top of the support.

7. The device of claim 1, wherein the free layer exists in a range from a top of the support to a top of the shield.

8. The device of claim 1, further comprising a pair of hard biases on the thin film, sandwiching the sensor.

9. The device of claim 1, further comprising an antiferromagnetic layer between the reference layer and the first electrode.

10. The device of claim 1, further comprising an antiferromagnetic layer between the reference layer and the second electrode.

11. The device of claim 1, wherein the reference layer is formed of a first reference and a second reference layer.

12. The device of claim 11, further comprising an antiparallel coupled layer between the first reference layer and the second reference layer.

13. The device of claim 1, wherein the sensor and a third part of the shield are arranged along a second direction, the second direction having a direction which is perpendicular to the first direction, the second direction extending along the wider surface of the thin film.

14. The device of claim 1, wherein the first part of the shield and the second part of the shield are separated.

15. The device of claim 14, wherein the sensor and a third part of the shield are arranged along a second direction, the second direction having a direction which is perpendicular to the first direction, the second direction extending along the wider surface of the thin film.

16. The device of claim 15, wherein

the first part of the shield and the third part of the shield are separated, and

the second part of the shield and the third part of the shield are separated.

17. A pressure sensor comprising:

a thin film bendable by a pressure;

a support which fixes the thin film and has a thickness larger than a thickness of the thin film;

a sensor on the thin film, the sensor comprising;

a first electrode on the thin film,

a second electrode,

a reference layer between the first electrode and the second electrode,

a free layer between the reference layer and the first electrode or between the reference layer and the second electrode, and

a spacer layer between the reference layer and the free layer,

wherein the magnetization of the free layer is changeable when the thin film is bent; and

a shield on the support, the shield comprising a soft magnetic material, wherein

the sensor and a first part of the shield are arranged along a first direction, the first direction extending along a wider surface of the thin film,

the sensor and a second part of the shield are arranged along a second direction, the second direction having a direction which is perpendicular to the first direction, the second direction extending along the wider surface of the thin film, and the soft magnetic material of the shield is formed entirely outside the thin film such that the soft magnetic material of the shield does not overlap the thin film in a direction perpendicular to the wider surface of the thin film.

18. The pressure sensor of claim 17, wherein the first part of the shield and the second part of the shield are separated.