Strain detection element, pressure sensor, microphone, blood pressure sensor, and touch panel

• US 10,048,150 B2
• Filed: 06/30/2015
• Issued: 08/14/2018
• 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
• Primary Examiner(s): Patel, Harshad R
• Assistant Examiner(s): ROY, PUNAM P
• Application Number:
  US14/755,633
• Publication Number:
  US 20160009545A1
• Time in Patent Office: 1,141 Days
• 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 stacked structure comprising:

a metal layer including a Cu_1-xAg_x alloy (1 at. %≤

x≤

20 at. %);

a first magnetic layer;

a second magnetic layer provided between the metal layer and the first magnetic layer; and

an intermediate layer provided between the first magnetic layer and the second magnetic layer,

an electrical resistance of the strain detection element being configured to change in accordance with a strain of the membrane.

2. The stacked structure according to claim 1, wherein a crystal grains size of the metal layer is 50 nm or less.

3. The stacked structure according to claim 1, wherein

the intermediate layer has a first interface opposing the first magnetic layer, and

an Ra value of the first interface is 0.3 nm or less,

the Ra value is expressed by the following formulas (1) and (2),

4. The stacked structure according to claim 1, wherein

the intermediate layer has a first interface opposing the first magnetic layer, and

an Rmax value of the first interface is 2.5 nm or less,

the Rmax value is expressed by the following formula (3),

R_max==max(Z(i))−

min(Z(i)) 

 

Formula (3)

wherein Z(i) is a position of the first interface in a height direction from the metal layer toward the first magnetic layer, max(Z(i)) is a maximum value of Z(i), and min(Z(i)) is a minimum value of Z(i).

5. The stacked structure according to claim 1, wherein the metal layer has a first face opposing the second magnetic layer, and

an Ra value of the first face is 2 nm or less,

the Ra value is expressed by the following formulas (1) and (2),

6. The stacked structure according to claim 1, wherein the metal layer has a first face opposing the second magnetic layer, and

an Rmax value of the first face is 10 nm or less,

the Rmax value is expressed by the following formula (3),

R_max==max(Z(i))−

min(Z(i)) 

 

Formula (3)

wherein Z(i) is a position of the first face in a height direction from the metal layer toward the first magnetic layer, max (Z(i)) is a maximum value of Z(i), and min(Z(i)) is a minimum value of Z(i).

7. The stacked structure according to claim 1, wherein the first magnetic layer includes boron.

8. The stacked structure according to claim 7, wherein a concentration of boron in at least part of the first magnetic layer is not less than 5 atomic percent and not more than 35 atomic percent.

9. The stacked structure according to claim 7, wherein

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

the first portion is located between the intermediate layer and the second portion, and

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

10. The stacked structure according to claim 1, wherein

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

the first portion is located between the intermediate layer and the second portion,

at least part of the first portion is crystalline, and

at least part of the second portion is amorphous.

11. The stacked structure according to claim 1, wherein the intermediate layer includes at least one selected from the group consisting of an oxide and a nitride.

12. A pressure sensor, comprising:

a membrane being deformable;

a supporting part supporting the membrane; and

a strain detection element comprising the stacked structure according to claim 1 and an electrode provided thereon, the strain detection element being fixed to the membrane and an electrical resistance of the strain detection element being configured to change in accordance with a strain of the membrane.

13. The pressure sensor according to claim 12, wherein the strain detection element is provided in a plurality.

14. A microphone, comprising:

the pressure sensor according to claim 12.

15. The stacked structure according to claim 1, further comprising:

a first layer provided between the metal layer and the first magnetic layer, the first layer including at least one selected from Ta, Ti, and TiN,

the second magnetic layer being provided between the first layer and the first magnetic layer,

the metal layer having a first face opposing the first layer,

the first layer having a second face opposing the second magnetic layer, and

the first face being rougher than the second face.

16. The stacked structure according to claim 15, wherein at least part of the first magnetic layer is amorphous.

17. A stacked structure comprising:

a metal layer including at least one selected from the group consisting of Cu, Al, Au, Ag, Ni, Fe, and Co;

a first magnetic layer;

a second magnetic layer provided between the metal layer and the first magnetic layer; and

an intermediate layer being provided between the first magnetic layer and the second magnetic layer,

a crystal grain size of the metal layer being 50 nm or less, and

an electrical resistance of the strain detection element being configured to change in accordance with a strain of the membrane.

18. The stacked structure according to claim 17, further comprising:

a first layer provided between the metal layer and the first magnetic layer, the first layer including at least one selected from Ta, Ti, and TiN,

the second magnetic layer being provided between the first layer and the first magnetic layer,

the metal layer having a first face opposing the first layer,

the first layer having a second face opposing the second magnetic layer, and

the first face being rougher than the second face.

19. The stacked structure according to claim 18, wherein at least part of the first magnetic layer is amorphous.