Multilayered Piezoelectric Thin Film Element

Abstract

A piezoelectric thin film element having a first electrode, a second electrode and a piezoelectric thin film between the electrodes, wherein the thin film comprises a laminate having two or more piezoelectric thin film layers and wherein a first thin film layer is doped by one or more dopants and a second film layer is doped by one or more dopants and wherein at least one dopant of the second thin film layer is different from the dopant or dopants of the first thin film layer.

1 . A piezoelectric thin film element having a first electrode, a second electrode and a piezoelectric thin film between the electrodes, wherein the thin film comprises a laminate having two or more piezoelectric thin film layers and wherein a first thin film layer is doped by one or more dopants and a second thin film layer is doped by one or more dopants and wherein at least one dopant of the second thin film layer is different from the dopant or dopants of the first thin film layer. 
     
     
         2 . A piezoelectric thin film element according to  claim 1 , in which the dopants are selected from the group of dopant types consisting of donor dopants, acceptor dopants and isovalent dopants. 
     
     
         3 . A piezoelectric thin film element according to  claim 1 , in which the thin film layers comprise a crystal or crystallites based on metal oxides which have a perovskite crystal structure (ABO 3 ). 
     
     
         4 . A piezoelectric thin film element according to  claim 3 , in which the dopants occupy the same or different co-ordination sites (A-site or B-site) in the perovskite crystal structure. 
     
     
         5 . A piezoelectric thin film element according to  claim 1 , in which the laminate further comprises one or more thin film layers which are undoped. 
     
     
         6 . A piezoelectric thin film element according to  claim 1 , in which the laminate comprises one or more further thin film layers which are doped by one or more dopants which are the same as or different to the dopant or dopants of the first thin film layer and/or the dopants of the second thin film layer. 
     
     
         7 . A piezoelectric thin film element according to  claim 1 , in which the first thin film layer is singly doped by a first dopant and the second thin film layer is singly doped by a second dopant. 
     
     
         8 . A piezoelectric thin film element according to  claim 7 , in which the first dopant and the second dopant are of the same dopant type or of a different dopant type. 
     
     
         9 . A piezoelectric thin film element according to  claim 7 , in which the laminate comprises one or more further thin film layers which are singly doped by dopants of the same or different dopant type. 
     
     
         10 . A piezoelectric thin film element according to  claim 7 , in which the laminate comprises two or more thin film layers which are alternately doped by dopants of a first dopant type or by a dopant of a first dopant type and a dopant of a second dopant type. 
     
     
         11 . A piezoelectric thin film element according to  claim 10 , in which any two adjacent thin film layers are alternately doped by a dopant of the first dopant type and a dopant of the second dopant type. 
     
     
         12 . A piezoelectric thin film element according to  claim 10 , in which any one thin film layer which is doped is adjacent a thin film layer which is undoped or doped and any two sequential thin film layers which are doped, are alternately doped by a dopant of the first dopant type and a dopant of the second dopant type. 
     
     
         13 . A piezoelectric thin film element according to  claim 10 , in which the laminate comprises a first series of adjacent thin film layers which are doped by a dopant of the first dopant type and a second series of adjacent thin film layers which are doped by a dopant of the second dopant type. 
     
     
         14 . A piezoelectric thin film element according to  claim 10 , in which similarly doped thin film layers define a gradient in dopant concentration across thin film layers. 
     
     
         15 . A piezoelectric thin film according to  claim 14 , in which the dopant concentration increases or decreases from the first electrode to the second electrode. 
     
     
         16 . A piezoelectric thin film element according to  claim 14 , in which the dopant concentration increases from the first electrode and decreases to the second electrode. 
     
     
         17 . A piezoelectric thin film element according to  claim 1 , in which one or more thin film layers define a gradient in dopant concentration within the thin film layer. 
     
     
         18 . A method for manufacturing a piezoelectric thin film element having a first electrode, a second electrode and a piezoelectric thin film between the electrodes, which method comprises a first step of forming a piezoelectric thin film layer on an electrode and one or more further steps of forming a piezoelectric thin film layer on the thin film layer whereby to form a laminate comprising a plurality of piezoelectric thin film layers wherein a first thin film layer is doped by one or more dopants and a second film layer is doped by one or more dopants and wherein at least one dopant of the second thin film layer is different from the dopant or dopants of the first thin film layer. 
     
     
         19 . (canceled) 
     
     
         20 . A method according to  claim 18 , in which the dopants are selected from the group of dopant types consisting of donor dopants, acceptor dopants and isovalent dopants. 
     
     
         21 . A method according to  claim 18 , in which the thin film layers comprise a crystal or crystallites based on metal oxides which have a perovskite crystal structure (ABO 3 ). 
     
     
         22 .- 24 . (canceled) 
     
     
         25 . A method according to  claim 18 , in which the first and further steps form a laminate in which the first thin film layer is singly doped by a first dopant and the second thin film layer is singly doped by a second dopant. 
     
     
         26 .- 34 . (canceled) 
     
     
         35 . An actuator for a printhead, which actuator comprises a piezoelectric element according to  claim 1 . 
     
     
         36 . A printhead, comprising the actuator of  claim 35 . 
     
     
         37 . An ink-jet printer, comprising the printhead of  claim 36 .