IP Library › Granted Patent US 12713833
Granted Patent B2
US 12713833 · App. 17/917,055 · Granted Aug 18, 2026

Piezoelectric stack, method of manufacturing piezoelectric stack, and piezoelectric element

Inventors: Toshiaki Kuroda (Hitachi, JP); Kenji Shibata (Hitachi, JP); Kazutoshi Watanabe (Hitachi, JP); Takeshi Kimura (Hitachi, JP)
Assignee: SUMITOMO CHEMICAL COMPANY, LIMITED
H10N39/00B06B1/0261H10N30/20H10N30/88B06B1/0622
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Quick Facts
Patent No.
US 12713833
App. No.
17/917,055
Filed
Oct 5, 2022
Granted
Aug 18, 2026
Kind
B2
Art Unit
2837
USPC
310/316.01
Abstract

There is provided a piezoelectric stack, including: a substrate; an output-side bottom electrode film on the substrate; an output-side piezoelectric film, being an oxide film, on the output-side bottom electrode film; an output-side top electrode film on the output-side piezoelectric film; an input-side bottom electrode film on the substrate; an input-side piezoelectric film, being a nitride film, on the input-side bottom electrode film; an input-side top electrode film on the input-side piezoelectric film; and an ultrasonic output part and ultrasonic input part placed in such a manner as not overlapping each other when viewed from a top surface of the substrate, the ultrasonic output part comprising a stacked part of the output-side bottom electrode film, the output-side piezoelectric film, and the output-side top electrode film, the ultrasonic input part comprising a stacked part of the input-side bottom electrode film, the input-side piezoelectric film, and the input-side top electrode film.

Claims (45)

1 . A piezoelectric element comprising:

a substrate;

an output-side bottom electrode film on the substrate;

an output-side piezoelectric film, being an oxide film, on the output-side bottom electrode film;

an output-side top electrode film on the output-side piezoelectric film;

an input-side bottom electrode film on the substrate;

an input-side piezoelectric film, being a nitride film, on the input-side bottom electrode film;

an input-side top electrode film on the input-side piezoelectric film; and

an ultrasonic output part and ultrasonic input part placed in such a manner as not overlapping each other when viewed from a top surface of the substrate,

the output-side piezoelectric film is separated from the input-side piezoelectric film by a gap,

the ultrasonic output part comprising a stacked part of the output-side bottom electrode film, the output-side piezoelectric film, and the output-side top electrode film,

the ultrasonic input part comprising a stacked part of the input-side bottom electrode film, the input-side piezoelectric film, and the input-side top electrode film.

2 . The piezoelectric element according to claim 1 , wherein the ultrasonic output part and the ultrasonic input part are not in contact with each other.

3 . The piezoelectric element according to claim 1 , wherein the output-side piezoelectric film, being a deposited film, contains any one of potassium sodium niobium oxide, lead-zirconium-titanium oxide, bismuth sodium titanium oxide, or bismuth ferrite.

4 . The piezoelectric element according to claim 1 , wherein the input-side piezoelectric film, being a deposited film, contains aluminum nitride.

5 . A method of manufacturing the piezoelectric element according to claim 1 , comprising:

depositing the output-side bottom electrode film and the input-side bottom electrode film on the substrate;

depositing the output-side piezoelectric film, being an oxide film, on the output-side bottom electrode film;

depositing a protective film that protects the output-side piezoelectric film;

depositing the input-side piezoelectric film, being a nitride film, on the input-side bottom electrode film;

exposing the output-side piezoelectric film by removing the protective film by etching; and

depositing the output-side top electrode film on the output-side piezoelectric film and depositing the input-side top electrode film on the input-side piezoelectric film, thereby

producing a stack in which the ultrasonic output part and the ultrasonic input part are placed in such a manner as not overlapping each other when viewed from the top surface of the substrate,

the ultrasonic output part comprising the stacked part of the output-side bottom electrode film, the output-side piezoelectric film, and the output-side top electrode film,

the ultrasonic input part comprising the stacked part of the input-side bottom electrode film, the input-side piezoelectric film, and the input-side top electrode film.

6 . The method of manufacturing the piezoelectric element according to claim 5 , wherein the protective film is any one of a film containing silicon dioxide, a film containing lanthanum nickel oxide, or a film containing strontium ruthenium oxide.

7 . The piezoelectric element according to claim 1 , further comprising:

a voltage applicator connected between the output-side bottom electrode film and the output-side top electrode film; and

a voltage detector connected between the input-side bottom electrode film and the input-side top electrode film,

wherein the output-side piezoelectric film deforms under a voltage application from the voltage applicator applying a predetermined electric field between the output-side bottom electrode film and the output-side top electrode film, and ultrasonic waves generated due to a deformation of the output-side piezoelectric film are transmitted from the ultrasonic output part, and the ultrasonic input part receives the ultrasonic waves reflected by a test object, and a voltage generated between the input-side bottom electrode film and the input-side top electrode film due to a deformation of the input-side piezoelectric film is detected by the voltage detector.

8 . The piezoelectric element according to claim 2 , wherein the output-side piezoelectric film, being a deposited film, contains any one of potassium sodium niobium oxide, lead-zirconium-titanium oxide, bismuth sodium titanium oxide, or bismuth ferrite.

9 . The piezoelectric element according to claim 2 , wherein the input-side piezoelectric film, being a deposited film, contains aluminum nitride.

10 . The piezoelectric element stack according to claim 3 , wherein the input-side piezoelectric film, being a deposited film, contains aluminum nitride.

11 . The piezoelectric element according to claim 2 , further comprising:

a voltage applicator connected between the output-side bottom electrode film and the output-side top electrode film; and

a voltage detector connected between the input-side bottom electrode film and the input-side top electrode film,

wherein the output-side piezoelectric film deforms under a voltage application from the voltage applicator applying a predetermined electric field between the output-side bottom electrode film and the output-side top electrode film, and ultrasonic waves generated due to a deformation of the output-side piezoelectric film are transmitted from the ultrasonic output part, and the ultrasonic input part receives the ultrasonic waves reflected by a test object, and a voltage generated between the input-side bottom electrode film and the input-side top electrode film due to a deformation of the input-side piezoelectric film is detected by the voltage detector.

12 . The piezoelectric element according to claim 3 , further comprising:

a voltage applicator connected between the output-side bottom electrode film and the output-side top electrode film; and

a voltage detector connected between the input-side bottom electrode film and the input-side top electrode film,

wherein the output-side piezoelectric film deforms under a voltage application from the voltage applicator applying a predetermined electric field between the output-side bottom electrode film and the output-side top electrode film, and ultrasonic waves generated due to a deformation of the output-side piezoelectric film are transmitted from the ultrasonic output part, and the ultrasonic input part receives the ultrasonic waves reflected by a test object, and a voltage generated between the input-side bottom electrode film and the input-side top electrode film due to a deformation of the input-side piezoelectric film is detected by the voltage detector.

13 . The piezoelectric element according to claim 4 , further comprising:

a voltage applicator connected between the output-side bottom electrode film and the output-side top electrode film; and

a voltage detector connected between the input-side bottom electrode film and the input-side top electrode film,

wherein the output-side piezoelectric film deforms under a voltage application from the voltage applicator applying a predetermined electric field between the output-side bottom electrode film and the output-side top electrode film, and ultrasonic waves generated due to a deformation of the output-side piezoelectric film are transmitted from the ultrasonic output part, and the ultrasonic input part receives the ultrasonic waves reflected by a test object, and a voltage generated between the input-side bottom electrode film and the input-side top electrode film due to a deformation of the input-side piezoelectric film is detected by the voltage detector.