Piezoelectric laminate, production method for piezoelectric laminate, and piezoelectric element

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.

1 . A piezoelectric stack 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 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 stack according to  claim 1 , wherein the ultrasonic output part and the ultrasonic input part are not in contact with each other. 
     
     
         3 . The piezoelectric stack 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 stack according to  claim 1 , wherein the input-side piezoelectric film, being a deposited film, contains aluminum nitride. 
     
     
         5 . A method of manufacturing a piezoelectric stack, comprising:
 depositing an output-side bottom electrode film and an input-side bottom electrode film on a substrate;   depositing an 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 an 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 an output-side top electrode film on the output-side piezoelectric film and depositing an input-side top electrode film on the input-side piezoelectric film, thereby   producing a stack in which an ultrasonic output part and an ultrasonic input part are 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. 
   
     
     
         6 . The method of manufacturing a piezoelectric stack 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 . A piezoelectric element comprising:
 the piezoelectric stack according to  claim 1 ;   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 stack 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 stack according to  claim 2 , wherein the input-side piezoelectric film, being a deposited film, contains aluminum nitride. 
     
     
         10 . The piezoelectric stack according to  claim 3 , wherein the input-side piezoelectric film, being a deposited film, contains aluminum nitride. 
     
     
         11 . A piezoelectric element comprising:
 the piezoelectric stack according to  claim 2 ;   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 . A piezoelectric element comprising:
 the piezoelectric stack according to  claim 3 ;   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 . A piezoelectric element comprising:
 the piezoelectric stack according to  claim 4 ;   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.