PRESSURE SENSOR

• US 20160003697A1
• Filed: 06/17/2015
• Published: 01/07/2016
• Est. Priority Date: 07/02/2014
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: FUKUZAWA, HIDEAKI, FUJI, YOSHIHIKO, OKAMOTO, KAZUAKI, HORI, AKIO, YUZAWA, AKIKO
• Granted Patent: US 10,082,435 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01L 9/0041 Transmitting or indicating the displacement of flexible diaphragms
• CPC Class Codes: G01L 9/0047 Diaphragm with non uniform thickness, e.g. with grooves, bosses or continuously varying thickness
• CPC Class Codes: G01L 9/008 using piezoelectric devices piezoelectric resonators G01L9/0022; surface acoustic waves G01L9/0025
• CPC Class Codes: G01L 9/16 by making use of variations in the magnetic properties of material resulting from the application of stress

Abstract

A pressure sensor according to an embodiment includes: a support member; a membrane supported by the support and having flexibility; and a strain detection element formed on the membrane. The strain detection element includes a first magnetic layer formed on the membrane and having a magnetization, a second magnetic layer having a magnetization, and an intermediate layer formed between the first magnetic layer and the second magnetic layer. A direction of at least one of the magnetization of the first magnetic layer and the magnetization of the second magnetic layer changes relatively to that of the other depending on a strain of the membrane. Moreover, the membrane includes an oxide layer that includes aluminum.

Claims

1. A pressure sensor, comprising:

a support member;

a membrane supported by the support and having flexibility; and

a strain detection element formed on the membrane,

the strain detection element including a first magnetic layer formed on the membrane and having a magnetization, a second magnetic layer having a magnetization, and an intermediate layer formed between the first magnetic layer and the second magnetic layer, and a direction of at least one of the magnetization of the first magnetic layer and the magnetization of the second magnetic layer changing relatively to that of the other depending on a strain of the membrane, and

the membrane including an oxide layer that includes aluminum.

2. The pressure sensor according to claim 1, wherein

the membrane comprises:

a first film mounted with the strain detection element and including an oxide that includes aluminum;

a second film positioned on a side of the support and including an oxide that includes aluminum; and

a third film sandwiched between the first film and the second film.

3. The pressure sensor according to claim 1, wherein

the membrane comprises:

a first film including an oxide that includes aluminum; and

a third film, and

the third film is positioned between the first film and the strain detection element.

4. The pressure sensor according to claim 1, wherein

the membrane comprises:

a second film including an oxide that includes aluminum; and

a third film, and

the second film is positioned between the third film and the strain detection element.

5. The pressure sensor according to any one of claims 2 to 4, wherein

a film formed by a material including SiNx is employed as the third film.

6. The pressure sensor according to claim 2, wherein

a film thickness of the first film is not less than 10 μ

m and not more than 300 μ

m.

7. The pressure sensor according to claim 2, wherein

a film thickness of the second film is not less than 10 μ

m and not more than 300 μ

m.

8. The pressure sensor according to claim 1, wherein

the membrane is configured from a single film including an oxide that includes aluminum.

9. The pressure sensor according to claim 8, wherein

a film thickness of the membrane configured from an oxide that includes aluminum is not less than 100 nm and not more than 2 μ

m.

10. The pressure sensor according to claim 1, wherein

the strain detection element is disposed at a position between a point on a boundary of the support and the membrane and a central point of a line segment joining a centroid of the membrane and the point on the boundary.

11. The pressure sensor according to claim 1, whereinor more strain detection elements are disposed on one membrane.

12. The pressure sensor according to of claim 1, wherein

the membrane has a rectangular shape.

13. The pressure sensor according to claim 1, wherein

a minimum circumscribed rectangle that circumscribes a shape of the membrane includes:

a first side;

a second side separated from the first side;

a third side connected to one end of the first side and one end of the second side;

a fourth side connected to the other end of the first side and the other end of the second side; and

a centroid of the minimum circumscribed rectangle, and

the strain detection elements are disposed on the membrane, and aligned in parallel to the first side, the strain detection elements are disposed on an area on the membrane that overlaps a region configured from the first side and line segments joining both ends of the first side and the centroid of the minimum circumscribed rectangle.

14. The pressure sensor according to claim 1, wherein

a hard magnetic body is further adjacent to a periphery of the strain detection element disposed on the membrane having flexibility.

15. The pressure sensor according to claim 14, wherein

a material including CoPt or FePt is employed as the hard magnetic body.

16. The pressure sensor according to claim 1, wherein

the strain detection element disposed on the membrane having flexibility is buried by a layer of an oxide including aluminum showing insulation properties.

17. A pressure sensor, comprising:

a support member;

a membrane supported by the support and having flexibility; and

a strain detection element formed on the membrane,

the membrane comprising;

a first film including an oxide that includes aluminum;

a second film including an oxide that includes aluminum; and

a third film sandwiched between the first film and the second film, and

the strain detection element including a piezoelectric element whose voltage changes when a strain is applied thereto.

18. The pressure sensor according to claim 17, wherein

the third film includes a silicon nitride film.