Dielectric thin film, dielectric thin film element, piezoelectric actuator, piezoelectric sensor, head assembly, head stack assembly, hard disk drive, printer head and inkjet printer device

Patent metadata

Field	Value
Publication number	US-12329036-B2
Application number	US-201917274897-A
Country	US
Kind code	B2
Filing date	Sep 11, 2019
Priority date	Sep 12, 2018
Publication date	Jun 10, 2025
Grant date	Jun 10, 2025

Abstract

Provided is a dielectric thin film including a metal oxide. The metal oxide includes bismuth, sodium, barium, and titanium, at least a part of the metal oxide is a tetragonal crystal having a perovskite structure, and a (100) plane of at least a part of the tetragonal crystal is oriented in a normal direction of a surface of the dielectric thin film.

First claim

The invention claimed is:

1. A dielectric thin film, including:
a metal oxide,
wherein the metal oxide includes bismuth, sodium, barium, and titanium,
at least a part of the metal oxide is a tetragonal crystal having a perovskite structure,
a (100) plane of the entirety of the tetragonal crystal is oriented in a normal direction of a surface of the dielectric thin film, and
the metal oxide is expressed by Chemical Formula 1 as follows:
(1− x )(Bi 0.5 Na 0.5 )TiO 3 - x BaTiO 3   (1),

where x satisfies 0.30≤x≤0.40.

2. The dielectric thin film according to claim 1 ,
wherein when an electric field parallel to the normal direction of the surface of the dielectric thin film is applied to the dielectric thin film, a peak area of a diffracted X-ray of a (001) plane of the tetragonal crystal does not increase.

3. The dielectric thin film according to claim 1 ,
wherein when an electric field parallel to the normal direction of the surface of the dielectric thin film is applied to the dielectric thin film, a peak area of a diffracted X-ray of a (001) plane of the tetragonal crystal increases.

4. The dielectric thin film according to claim 1 ,
wherein in a state in which an electric field parallel to the normal direction of the surface of the dielectric thin film is applied to the dielectric thin film,
a (100) plane of a part of the tetragonal crystal is oriented in the normal direction of the surface of the dielectric thin film, and
a (001) plane of another part of the tetragonal crystal is oriented in the normal direction of the surface of the dielectric thin film.

5. The dielectric thin film according to claim 1 ,
wherein [100] is a crystal orientation of the tetragonal crystal, and
the [100] of the tetragonal crystal is parallel to the normal direction of the surface of the dielectric thin film.

6. The dielectric thin film according to claim 1 ,
wherein the normal direction of the surface of the dielectric thin film corresponds to a thickness direction of the dielectric thin film.

7. A dielectric thin film element, comprising:
the dielectric thin film according to claim 1 .

8. The dielectric thin film element according to claim 7 , comprising:
a single crystal substrate; and
the dielectric thin film stacked on the single crystal substrate,
wherein a (100) plane of at least a part of the tetragonal crystal is oriented in a normal direction of a surface of the single crystal substrate.

9. The dielectric thin film element according to claim 8 , comprising:
the single crystal substrate;
a first electrode layer stacked on the single crystal substrate;
the dielectric thin film stacked on the single crystal substrate through the first electrode layer; and
a second electrode layer stacked on the dielectric thin film.

10. The dielectric thin film element according to claim 9 , further comprising:
at least one intermediate layer,
wherein the intermediate layer is disposed between the single crystal substrate and the first electrode layer, between the first electrode layer and the dielectric thin film, or between the dielectric thin film and the second electrode layer.

11. The dielectric thin film element according to claim 8 , comprising:
the single crystal substrate;
a first electrode layer stacked on the single crystal substrate;
a first crystalline layer stacked on the first electrode layer;
a second crystalline layer stacked on the first crystalline layer;
the dielectric thin film stacked on the second crystalline layer; and
a second electrode layer stacked on the dielectric thin film,
wherein the first crystalline layer includes a LaNiO 3 crystal having a perovskite structure,
the second crystalline layer includes a SrRuO 3 crystal having the perovskite structure,
a (100) plane of the first crystalline layer is oriented in a normal direction of a surface of the single crystal substrate, and
a (100) plane of the second crystalline layer is oriented in the normal direction of the surface of the single crystal substrate.

12. The dielectric thin film element according to claim 8 , comprising:
the single crystal substrate;
a first electrode layer stacked on the single crystal substrate;
a first crystalline layer stacked on the first electrode layer;
a second crystalline layer stacked on the first crystalline layer;
the dielectric thin film stacked on the second crystalline layer; and
a second electrode layer stacked on the dielectric thin film,
wherein the first crystalline layer includes a LaNiO 3 crystal having a perovskite structure,
the second crystalline layer includes a (La, Sr)CoO 3 crystal having a perovskite structure,
a (100) plane of the first crystalline layer is oriented in a normal direction of a surface of the single crystal substrate, and
a (100) plane of the second crystalline layer is oriented in the normal direction of the surface of the single crystal substrate.

13. The dielectric thin film element according to claim 7 ,
wherein the dielectric thin film element is a piezoelectric element.

14. A piezoelectric sensor, comprising:
the dielectric thin film element according to claim 13 .

15. A piezoelectric actuator, comprising:
the dielectric thin film element according to claim 13 .

16. A head assembly, comprising:
the piezoelectric actuator according to claim 15 .

17. A head stack assembly, comprising:
the head assembly according to claim 16 .

18. A hard disk drive, comprising:
the head stack assembly according to claim 17 .

19. A printer head, comprising:
the piezoelectric actuator according to claim 15 .

20. An inkjet printer device, comprising:
the printer head according to claim 19 .

Assignees

• Tdk Corp
• Tokyo Inst Tech

Inventors

• Sato Yusuke
• Ishida Mirai
• Sato Wakiko
• Funakubo Hiroshi
• Shimizu Takao
• Hasegawa Miyu
• ISHIHAMA Keisuke

Classifications

• H10N30/708

  Intermediate layers, e.g. barrier, adhesion or growth control buffer layers · CPC title

• H10N30/079

  using intermediate layers, e.g. for growth control · CPC title

• H10N30/076

  by vapour phase deposition · CPC title

• G11B5/127

  Structure or manufacture of heads, e.g. inductive · CPC title

• G01L1/16 Primary

  using properties of piezoelectric devices · CPC title