STRAIN DETECTION ELEMENT, PRESSURE SENSOR, MICROPHONE, BLOOD PRESSURE SENSOR, AND TOUCH PANEL

• US 20160009545A1
• Filed: 06/30/2015
• Published: 01/14/2016
• Est. Priority Date: 07/02/2014
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: FUJI, Yoshihiko, FUKUZAWA, Hideaki, HORI, Akio, KAJI, Shiori
• Granted Patent: US 10,048,150 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01L 9/0042 Constructional details associated with semiconductive diaphragm sensors, e.g. etching, or constructional details of non-semiconductive diaphragms details about the integration or bonding of piezoresistor in or on the diaphragm G01L9/0052 and G01L9/0057 respectively
• CPC Class Codes: G01L 9/0044 Constructional details of non-semiconductive diaphragms
• 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 strain detection element is provided above a deformable membrane. Moreover, this strain detection element includes an electrode and a stacked body, the stacked body including: a first magnetic layer whose magnetization direction is variable according to a deformation of the membrane; a second magnetic layer provided facing the first magnetic layer; and an intermediate layer provided between these first magnetic layer and second magnetic layer, and at least part of the first magnetic layer is amorphous, and the electrode includes a metal layer configured from a Cu—Ag alloy.

Claims

1. A strain detection element provided above a deformable membrane, the strain detection element comprising:

an electrode; and

a stacked body provided above the electrode and including a first magnetic layer, a second magnetic layer, and an intermediate layer, the first magnetic layer having its magnetization direction being variable according to a deformation of the membrane, the second magnetic layer being provided facing the first magnetic layer, and the intermediate layer being provided between the first magnetic layer and the second magnetic layer, and

at least part of the first magnetic layer is amorphous, and

the electrode includes a metal layer configured from a Cu—

Ag alloy.

2. The strain detection element according to claim 1, wherein

a crystal grains size of the metal layer configured from the Cu—

Ag alloy is 50 nm or less.

3. The strain detection element according to claim 1, wherein

the electrode includes the metal layer configured from a Cu_1-xAg_x alloy (1 at. %≦

x≦

20 at. %).

5. The strain detection element according to claim 1, wherein

assuming that a direction in which the first magnetic layer, the second magnetic layer, and the intermediate layer are stacked is a height direction, and that an interface between the intermediate layer and the first magnetic layer is a first interface, then an Ra value of the first interface expressed by the following formulas (1) and (2) is 0.3 nm or less.

6. The strain detection element according to claim 1, wherein

assuming that a direction in which the first magnetic layer, the second magnetic layer, and the intermediate layer are stacked is a height direction, and that an interface between the intermediate layer and the first magnetic layer is a first interface, then an Rmax value of the first interface expressed by the following formula (3) is 2.5 nm or less.

R_max=max(Z(i))−

min(Z(i)) 

 

Formula (3)

(Z(i) is a position of the first interface in the height direction, max(Z(i)) is a maximum value of Z(i), and min(Z(i)) is a minimum value of Z(i))

7. The strain detection element according to claim 1, wherein

assuming that a direction in which the first magnetic layer, the second magnetic layer, and the intermediate layer are stacked is a height direction, and that a surface facing the stacked body of the metal layer is a metal layer upper surface, then an Ra value of the metal layer upper surface expressed by the following formulas (1) and (2) is 2 nm or less.

8. The strain detection element according to claim 1, wherein

assuming that a direction in which the first magnetic layer, the second magnetic layer, and the intermediate layer are stacked is a height direction, and that a surface facing the stacked body of the metal layer is a metal layer upper surface, then an Rmax value of the metal layer upper surface expressed by the following formula (3) is 10 nm or less.

R_max=max(Z(i))−

min(Z(i)) 

 

Formula (3)

(Z(i) is a position of the metal layer upper surface in the height direction, max (Z(i)) is a maximum value of Z(i), and min(Z(i)) is a minimum value of Z(i))

9. The strain detection element according to claim 1, wherein

the first magnetic layer includes boron.

10. The strain detection element according to claim 1, wherein

at least part of the first magnetic layer includes not less than 5 atomic percent and not more than 35 atomic percent of boron.

11. The strain detection element according to claim 9, wherein

the first magnetic layer includes a first portion contacting the intermediate layer and a second portion contacting the first portion, and

a concentration of boron in the first portion is lower than a concentration of boron in the second portion.

12. The strain detection element according to claim 1, wherein

the first magnetic layer includes a first portion contacting the intermediate layer and a second portion contacting the first portion,

at least part of the first portion is crystalline, and

at least part of the second portion is amorphous.

13. The strain detection element according to claim 1, wherein

the intermediate layer includes an oxide or a nitride.

14. The strain detection element according to claim 1, wherein

the intermediate layer includes magnesium oxide.

15. The strain detection element according to claim 1, wherein

a coercivity of the first magnetic layer is 4 Oe or less.

16. The strain detection element according to claim 1, wherein

a magnetostriction constant of the first magnetic layer is 1×

10<sup>−

5</sup> or more.

17. A pressure sensor, comprising:

a deformable membrane;

a supporting part which supports the membrane; and

the strain detection element described in claim 1, provided above the membrane.

18. The pressure sensor according to claim 17, wherein

the membrane is provided with a plurality of the strain detection elements described in claim 1.

19. A microphone, comprising:

the pressure sensor described in claim 17.

4. A strain detection element provided above a deformable membrane, the strain detection element comprising:

an electrode; and

a stacked body provided above the electrode and including a first magnetic layer, a second magnetic layer, and an intermediate layer, the first magnetic layer having its magnetization direction being variable according to a deformation of the membrane, the second magnetic layer being provided facing the first magnetic layer, and the intermediate layer being provided between the first magnetic layer and the second magnetic layer, and

at least part of the first magnetic layer is amorphous,

the electrode includes a metal layer that includes at least one element selected from the group consisting of Cu, Al, Au, Ag, Ni, Fe, and Co, and

a crystal grain size of the metal layer is 50 nm or less.