# US 12,015,390 B2 · Bulk acoustic wave resonator

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- Number: US 12,015,390 B2
- Document ID: US12015390B2
- Status: Granted
- Kind: B2
- Application number: 17/438,878
- Filed: 2020-11-03
- Published: 2022-05-19
- Granted: 2024-06-18
- Earliest claimed: 2019-11-12
- Assignees: Mg Microelectronics Co., Ltd.
- Applicants: Mg Microelectronics Co., Ltd
- Inventors: Jianmin Miao; Ruizhen Zhang
- Web page: https://patentgrep.com/patent/US12015390B2

## CPC

- H03H 9/02015: {Characteristics of piezoelectric layers, e.g. cutting angles}
- H03H 9/02118: {of lateral leakage between adjacent resonators}
- H03H 9/00: Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators (electro-acoustic transducers such as loudspeakers, microphones or gramophone pick-ups H04R; piezoelectric, electrostrictive or magnetostrictive devices with mechanical input or output, e.g. actuators or sensors, H10N30/00, H10N35/00)
- H03H 9/02007: {of bulk acoustic wave devices}
- H03H 9/02047: {Treatment of substrates}
- H03H 9/13: for networks consisting of piezoelectric or electrostrictive materials (for networks using surface acoustic waves H03H9/145)
- H03H 9/132: {characterized by a particular shape}
- H03H 9/171: {implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type}
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)

## Abstract

Provided is a bulk acoustic wave resonator. The bulk acoustic wave resonator includes an upper electrode, a piezoelectric layer and a lower electrode. The piezoelectric layer is disposed between the upper electrode and the lower electrode. At least one boundary of an orthogonal projection of the piezoelectric layer on the lower electrode includes a plurality of sawtooth structures.

## Claims

### Claim 1

A bulk acoustic wave resonator, comprising: an upper electrode, a piezoelectric layer and a lower electrode, wherein
the piezoelectric layer is disposed between the upper electrode and the lower electrode; and
at least one boundary of an orthogonal projection of the piezoelectric layer on the lower electrode comprises a plurality of sawtooth structures;
wherein a center-to-center distance of adjacent sawtooth structures among the plurality of sawtooth structures is greater than or equal to 2 micrometers.

### Claim 2 (depends on 1)

The bulk acoustic wave resonator according to claim 1, wherein at least one boundary of orthogonal projections of the upper electrode and the lower electrode on a plane perpendicular to a thickness direction of the bulk acoustic wave resonator comprises a plurality of sawtooth structures.

### Claim 3 (depends on 1)

The bulk acoustic wave resonator according to claim 1, wherein a material of the piezoelectric layer is one of lead zirconate titanate piezoelectric ceramics, zinc oxide or aluminum nitride.

### Claim 4 (depends on 1)

The bulk acoustic wave resonator according to claim 1, wherein the at least one edge of the orthogonal projection of the piezoelectric layer on the lower electrode comprises a plurality of edges, each of the plurality of edges of the piezoelectric layer on the lower electrode comprises a plurality of sawtooth structures.

### Claim 5 (depends on 4)

The bulk acoustic wave resonator according to claim 4, wherein the plurality of sawtooth structures of each of the plurality of edges of the piezoelectric layer on the lower electrode are sequentially connected end to end on each of the plurality of edges.

### Claim 6 (depends on 1)

The bulk acoustic wave resonator according to claim 1, wherein a shape of the plurality of sawtooth structures comprises a triangle or a trapezoid.

### Claim 7 (depends on 1)

The bulk acoustic wave resonator according to claim 1, wherein a shape of an orthogonal projection of the bulk acoustic wave resonator on a plane perpendicular to a thickness direction of the bulk acoustic wave resonator comprises a polygon.

### Claim 8 (depends on 1)

The bulk acoustic wave resonator according to claim 1, wherein a material of the upper electrode and a material of the lower electrode is one of gold, molybdenum, aluminum, chromium or nickel.