Method of making a piezoelectric device

Patent metadata

Field	Value
Publication number	US-2025364967-A1
Application number	US-202519294900-A
Country	US
Kind code	A1
Filing date	Aug 8, 2025
Priority date	Dec 15, 2016
Publication date	Nov 27, 2025
Grant date	—

Abstract

A piezoelectric device includes a foundation structure and a plurality of metal islands distributed over a first area of a top surface of the foundation structure. A piezoelectric film resides over the foundation structure and is formed from a piezoelectric material. The piezoelectric film has a non-piezoelectric portion over the first area and a piezoelectric portion over a second area of the top surface of the foundation structure. Within the non-piezoelectric portion, the piezoelectric film is polarity patterned to have pillars and a mesh. The pillars of the piezoelectric material have a first polar orientation residing over corresponding ones of the plurality of metal islands. The mesh of the piezoelectric material has a second polar orientation, which is opposite that of the first polar orientation, and surrounds the pillars. In one embodiment, the metal islands are self-assembled islands.

First claim

What is claimed is:

1 . A method of making a piezoelectric device, comprising steps of:
providing a foundation structure; depositing a first metal over at least a first area of a top surface of the foundation structure to form a plurality of metal islands such that the plurality of metal islands self-assemble in a distributed manner over the at least the first area of the top surface of the foundation structure; depositing piezoelectric material over the at least the first area of the top surface of the foundation structure to form a piezoelectric film over the at least the first area of the top surface of the foundation structure, wherein the depositing of the piezoelectric material formed over the at least the first area of the top surface of the foundation structure to form the piezoelectric film further comprises polarity patterning the piezoelectric film formed into at least one non-piezoelectric portion, said the at least one non-piezoelectric portion further comprising:
forming pillars of the piezoelectric material including a first polar orientation residing over corresponding ones of the plurality of metal islands; and
forming a mesh of the piezoelectric material including a second polar orientation, which is opposite to that of the first polar orientation, and surrounding the pillars of the piezoelectric material;
depositing a base layer of the piezoelectric material, wherein the at least one non-piezoelectric portion is deposited such that the base layer is between the at least one non-piezoelectric portion and the foundation structure, the plurality of metal islands over and directly on the base layer.

2 . The method of claim 1 , further comprising:
forming a bottom electrode over the foundation structure, wherein the piezoelectric material in the base layer has the second polar orientation; and forming a top electrode over the at least one non-piezoelectric portion, wherein the at least one non-piezoelectric portion is over the base layer, and the at least one non-piezoelectric portion and the base layer are between the bottom electrode and the top electrode.

3 . The method of claim 1 , wherein the bottom electrode, the at least one non-piezoelectric portion, and the top electrode are deposited such that the at least one non-piezoelectric portion is in an outside region at least partially surrounding an active region.

4 . The method of claim 1 , wherein the depositing of the piezoelectric material to form the piezoelectric film includes depositing the piezoelectric film formed from the piezoelectric material over the at least first area of the top surface of the foundation structure and the plurality of metal islands.

5 . The method of claim 1 , wherein the depositing of the piezoelectric material to form the piezoelectric film includes depositing the piezoelectric film formed from the piezoelectric material over the at least first area of the top surface of the foundation structure and over a second area of the top surface of the foundation structure.

6 . The method of claim 1 , wherein the method further comprises:
depositing the first metal to form additional metal islands that are provided over at least a second area of the top surface of the foundation structure to form the additional metal islands, said the additional metal islands formed; and removing the additional metal islands in the at least the second area of the top surface of the foundation structure.

7 . The method of claim 6 , wherein the depositing of the piezoelectric material to form the piezoelectric film over the at least the first area of the top surface of the foundation structure further comprises depositing the piezoelectric film over the at least the second area of the top surface of the foundation structure.

8 . The method of claim 1 , wherein the piezoelectric material is chosen from a compound that includes a metal element and a non-metal element, and the plurality of metal islands consists of the metal element.

9 . The method of claim 1 , wherein the piezoelectric material is chosen from a compound that includes a metal element and a non-metal element, and the plurality of metal islands are essentially void of the non-metal element.

10 . A method of making a piezoelectric device, comprising steps of:
providing a foundation structure; depositing a first metal over at least a first area of a top surface of the foundation structure to form a plurality of metal islands such that the plurality of metal islands self-assemble in a distributed manner over the at least the first area of the top surface of the foundation structure; depositing piezoelectric material over the at least the first area of the top surface of the foundation structure to form a piezoelectric film over the at least the first area of the top surface of the foundation structure, wherein the depositing of the piezoelectric material formed over the at least the first area of the top surface of the foundation structure to form a piezoelectric film further comprises polarity patterning the piezoelectric film formed into at least one non-piezoelectric portion, said the at least one non-piezoelectric portion further comprising:
forming pillars of the piezoelectric material including a first polar orientation residing over corresponding ones of the plurality of metal islands; and
forming a mesh of the piezoelectric material including a second polar orientation, which is opposite to that of the first polar orientation, and surrounding the pillars of the piezoelectric material;
forming a first bottom electrode over the foundation structure; depositing a first top electrode over the first bottom electrode depositing a top electrode such that the at least one piezoelectric portion is between the first bottom electrode and the first top electrode; forming a second bottom electrode over the foundation structure; depositing a base layer of the piezoelectric material over the second bottom electrode, the base layer having the second polar orientation, and the plurality of metal islands are on the base layer; and depositing a second top electrode over the base layer such that the at least one non-piezoelectric portion and the base layer are between the second bottom electrode and the second top electrode.

11 . The method of claim 10 wherein:
the first bottom electrode and the first top electrode form part of a first transducer for a first bulk acoustic wave resonator; and
the second bottom electrode and the second top electrode form part of a second transducer for a second bulk acoustic wave resonator.

Assignees

• Qorvo Us Inc

Inventors

• Sadhu Jyothi Swaroop
• Wang Maria

Classifications

• H03H9/02015

  Characteristics of piezoelectric layers, e.g. cutting angles · CPC title

• H03H3/02 Primary

  for the manufacture of piezoelectric or electrostrictive resonators or networks (H03H3/08 takes precedence) · CPC title

• H03H2003/023

  the resonators or networks being of the membrane type · CPC title

• H03H2003/025

  the resonators or networks comprising an acoustic mirror · CPC title

• H03H9/0211 Primary

  of reflections · CPC title