Method of manufacturing bulk acoustic wave device with atomic layer deposition of piezoelectric layer

Abstract

Aspects of this disclosure relate to method of manufacturing a bulk acoustic wave device. The method can include providing a bulk acoustic wave device structure including a first piezoelectric layer and forming a second piezoelectric layer over the first piezoelectric layer by atomic layer deposition. The second piezoelectric layer can have an opposite polarization relative to the first piezoelectric layer.

What is claimed is: 
     
         1 . A method of manufacturing a bulk acoustic wave device, the method comprising: 
 providing a bulk acoustic wave device structure including a first piezoelectric layer; and   forming a second piezoelectric layer over the first piezoelectric layer by atomic layer deposition, the second piezoelectric layer having an opposite polarization relative to the first piezoelectric layer.   
     
     
         2 . The method of  claim 1  further comprising depositing a third piezoelectric layer over the second piezoelectric layer using a process different than atomic layer deposition, the third piezoelectric layer having a same polarization as the second piezoelectric layer. 
     
     
         3 . The method of  claim 2  wherein the third piezoelectric layer is a doped piezoelectric layer. 
     
     
         4 . The method of  claim 2  wherein the first piezoelectric layer and the third piezoelectric layer are a scandium doped aluminum nitride layers. 
     
     
         5 . The method of  claim 2  further comprising depositing a fourth piezoelectric layer over the third piezoelectric layer by atomic layer deposition, the fourth piezoelectric layer having an opposite polarization relative to the third piezoelectric layer. 
     
     
         6 . The method of  claim 5  further comprising depositing a fifth piezoelectric layer over the fourth piezoelectric layer using the process different than atomic layer deposition. 
     
     
         7 . The method of  claim 2  wherein the process different than atomic layer deposition includes sputtering. 
     
     
         8 . The method of  claim 1  further comprising forming a third piezoelectric layer over the second piezoelectric layer by atomic layer deposition, the third piezoelectric layer having a same polarization as the first piezoelectric layer. 
     
     
         9 . The method of  claim 1  wherein at least one of the first piezoelectric layer and the second piezoelectric layer includes aluminum nitride. 
     
     
         10 . The method of  claim 1  further comprising sputtering the first piezoelectric layer. 
     
     
         11 . The method of  claim 1  wherein the bulk acoustic wave device structure includes a first electrode under the first piezoelectric layer, and the method further includes forming a second electrode over the second piezoelectric layer such that at least the first piezoelectric layer and second piezoelectric layer are included between the first electrode and the second electrode. 
     
     
         12 . The method of  claim 1  wherein a bulk acoustic wave device formed by the method has a resonant frequency in a range from 10 gigahertz to 40 gigahertz. 
     
     
         13 . The method of  claim 1  wherein the second piezoelectric layer is a scandium doped aluminum nitride layer. 
     
     
         14 . The method of  claim 13 wherein an oxygen source is included in vapor for the atomic layer deposition of the second piezoelectric layer. 
     
     
         15 . A method of manufacturing a bulk acoustic wave device, the method comprising: 
 providing a bulk acoustic wave device structure that includes a first aluminum nitride piezoelectric layer; and   forming a second aluminum nitride piezoelectric layer over the first aluminum nitride piezoelectric layer by atomic layer deposition, the second aluminum nitride piezoelectric layer having an inverted polarization relative to the first aluminum nitride piezoelectric layer.   
     
     
         16 . The method of  claim 15  further comprising depositing a third aluminum nitride piezoelectric layer over the second aluminum nitride piezoelectric layer, the third aluminum nitride layer piezoelectric layer including a dopant, and the third aluminum nitride piezoelectric layer having a same polarization as the second aluminum nitride piezoelectric layer. 
     
     
         17 . The method of  claim 15  further comprising forming another aluminum nitride piezoelectric layer over the second aluminum nitride piezoelectric layer by atomic layer deposition. 
     
     
         18 . A method of manufacturing a bulk acoustic wave device, the method comprising: 
 sputtering a first piezoelectric layer over a first electrode;   depositing a second piezoelectric layer over the first piezoelectric layer by atomic layer deposition, the second piezoelectric layer having an inverted polarization relative to the first piezoelectric layer;   sputtering a third piezoelectric layer directly over the second piezoelectric layer, the third piezoelectric layer having a same polarization as the second piezoelectric layer; and   forming a second electrode over the third piezoelectric layer such that a stack of piezoelectric layers is positioned between the first electrode and the second electrode, the stack of piezoelectric layers including at least the first, second and third piezoelectric layers.   
     
     
         19 . The method of  claim 18  wherein the third piezoelectric layer includes aluminum nitride. 
     
     
         20 . The method of  claim 19  wherein the third piezoelectric layer is doped with scandium.