# US 11,909,380 B2 · Acoustic resonator and method of manufacturing the same

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- Number: US 11,909,380 B2
- Document ID: US11909380B2
- Status: Granted
- Kind: B2
- Application number: 16/668,118
- Filed: 2019-10-30
- Published: 2020-02-27
- Granted: 2024-02-20
- Earliest claimed: 2015-12-18
- Assignees: Samsung Electro-Mechanics Co., Ltd.
- Applicants: Samsung Electro-Mechanics Co., Ltd.
- Inventors: Ran Hee Shin; Tae Kyung Lee; Sung Han; Yun Sung Kang; Sung Sun Kim; Jin Suk Son; Jeong Suong Yang; Hwa Sun Lee; Eun Tae Park
- Web page: https://patentgrep.com/patent/US11909380B2

## CPC

- H03H 9/173: {Air-gaps}
- H03H 3/02: for the manufacture of piezoelectric or electrostrictive resonators or networks (H03H3/08 takes precedence)
- H03H 9/02015: {Characteristics of piezoelectric layers, e.g. cutting angles}
- H03H 9/174: {Membranes}
- H03H 9/02118: {of lateral leakage between adjacent resonators}
- H03H 2003/021: {the resonators or networks being of the air-gap type}
- H03H 2003/023: {the resonators or networks being of the membrane type}
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)

## Abstract

An acoustic resonator and a method of manufacturing the same are provided. The acoustic resonator includes a resonating part including a first electrode, a second electrode, and a piezoelectric layer; and a plurality of seed layers disposed on one side of the resonating part.

## Claims

### Claim 1

An acoustic resonator comprising:
a resonating part comprising a first electrode, a second electrode, and a piezoelectric layer disposed between the first electrode and the second electrode; and
a plurality of seed layers disposed on one side of the resonating part,
wherein the plurality of seed layers comprise a first seed layer below the first electrode and a second seed layer below the first seed layer, and
wherein a lattice mismatch between the first electrode and the second seed layer is less than a lattice mismatch between the first seed layer and the first electrode.

### Claim 2 (depends on 1)

The acoustic resonator of claim 1, further comprising a substrate disposed on the opposite side of the plurality of seed layers from the resonating part from.

### Claim 3 (depends on 2)

The acoustic resonator of claim 2, wherein an air gap is disposed between the substrate and the plurality of seed layers.

### Claim 4 (depends on 2)

The acoustic resonator of claim 2, wherein the resonating part further comprises a protection layer.

### Claim 5 (depends on 2)

The acoustic resonator of claim 2, wherein a membrane is interposed between the substrate and the plurality of seed layers, and
an air gap is disposed between the substrate and the membrane.

### Claim 6 (depends on 5)

The acoustic resonator of claim 5, wherein the membrane comprises a plurality of membrane layers, and
at least one membrane layer of the plurality of membrane layers is an etching stopper.

### Claim 7 (depends on 1)

The acoustic resonator of claim 1,
wherein the first seed layer comprises a material having the same crystalline system as a material of the piezoelectric layer, and
wherein the second seed layer comprises a material having the same unit cell geometry as a material of the first seed layer.

### Claim 8 (depends on 7)

The acoustic resonator of claim 7, wherein a thickness of the first seed layer or the second seed layer is within a range of 10 Å to 1,000 Å.

### Claim 9 (depends on 7)

The acoustic resonator of claim 7, wherein the piezoelectric layer, the first seed layer, and the second seed layer each comprise a material having a hexagonal crystal system.

### Claim 10 (depends on 9)

The acoustic resonator of claim 9, wherein the second seed layer comprises a material having a hexagonal close packed structure.

### Claim 11 (depends on 9)

The acoustic resonator of claim 9, wherein the piezoelectric layer comprises aluminum nitride or doped aluminum nitride,
the first electrode comprises molybdenum,
the first seed layer comprises aluminum nitride, and
the second seed layer comprises titanium.

### Claim 12 (depends on 7)

The acoustic resonator of claim 7, wherein an upper surface of the second seed layer corresponds to a (002) plane of hexagonal lattice.

### Claim 13 (depends on 7)

The acoustic resonator of claim 7, wherein the piezoelectric layer comprises aluminum nitride or doped aluminum nitride,
the first electrode comprises molybdenum,
the first seed layer comprises titanium, and
the second seed layer comprises aluminum nitride.

### Claim 14 (depends on 1)

The acoustic resonator of claim 1,
wherein a lattice mismatch between the first seed layer and the second seed layer is less than or equal to 7.64%.

### Claim 15 (depends on 1)

The acoustic resonator of claim 1, wherein the plurality of seed layers comprise a first seed layer and a second seed layer;
wherein a lattice mismatch between the first seed layer and the second seed layer is 5.49%.

### Claim 16

An acoustic resonator comprising:
a resonating part comprising a first electrode, a second electrode, and a piezoelectric layer disposed between the first electrode and the second electrode; and
a plurality of seed layers disposed on one side of the resonating part,
wherein a first seed layer and a second seed layer of the plurality of seed layers, comprise different material from each other and a same crystalline lattice structure as each other.

### Claim 17 (depends on 16)

The acoustic resonator of claim 16, wherein the second seed layer comprises a material having a hexagonal close packed structure.

### Claim 18 (depends on 16)

The acoustic resonator of claim 16, wherein the piezoelectric layer comprises aluminum nitride or doped aluminum nitride,
the first electrode comprises molybdenum, and
the first seed layer comprises aluminum nitride.

### Claim 19 (depends on 16)

The acoustic resonator of claim 16, wherein the piezoelectric layer comprises aluminum nitride or doped aluminum nitride,
the first electrode comprises molybdenum, and
the first seed layer comprises titanium.

### Claim 20

An acoustic resonator comprising:
a resonating part comprising a first electrode, a second electrode, and a piezoelectric layer disposed between the first electrode and the second electrode;
a plurality of seed layers disposed on one side of the resonating part;
a substrate disposed on the opposite side of the plurality of seed layers from the resonating part; and
a plurality of membrane layers interposed between the substrate and the plurality of seed layers.