ACOUSTIC WAVE RESONATOR, FILTER, AND MULTIPLEXER

• US 20190326878A1
• Filed: 04/04/2019
• Published: 10/24/2019
• Est. Priority Date: 04/20/2018
• Status: Active Grant

• Current Assignee: Taiyo Yuden Company Limited (Taiyo Yuden Co)
• Original Assignee: Taiyo Yuden Company Limited (Taiyo Yuden Co)
• Inventors: KAKITA, Naoki, KAWACHI, Osamu, OIKAWA, Rei
• Granted Patent: US 11,595,019 B2
• Time in Patent Office: Days
• CPC Class Codes: H03H 3/08 for the manufacture of resonators or networks using surface acoustic waves
• CPC Class Codes: H03H 9/02559 of lithium niobate or lithium-tantalate substrates
• CPC Class Codes: H03H 9/02574 of combined substrates, multilayered substrates, piezoelectrical layers on not-piezoelectrical substrate
• CPC Class Codes: H03H 9/02834 of temperature influence cut angles H03H9/02543
• CPC Class Codes: H03H 9/059 consisting of mounting pads or bumps
• CPC Class Codes: H03H 9/1071 the enclosure being defined by a frame built on a substrate and a cap, the frame having no mechanical contact with the SAW device
• CPC Class Codes: H03H 9/6483 Ladder SAW filters
• CPC Class Codes: H10N 30/072 by laminating or bonding of piezoelectric or electrostrictive bodies
• CPC Class Codes: H10N 30/50 having a stacked or multilayer structure
• CPC Class Codes: H10N 30/708 Intermediate layers, e.g. barrier, adhesion or growth control buffer layers
• CPC Class Codes: H10N 30/87 Electrodes or interconnections, e.g. leads or terminals

Abstract

An acoustic wave resonator includes: a support substrate; a piezoelectric substrate located on the support substrate; a first amorphous layer that is in contact with the support substrate and is mainly composed of one or more constituent elements of the support substrate; a second amorphous layer that is in contact with the piezoelectric substrate and the first amorphous layer, is mainly composed of one or more constituent elements of the piezoelectric substrate, and is thinner than the first amorphous layer; and a pair of comb-shaped electrodes that is located on an opposite surface of the piezoelectric substrate from the support substrate, each of the pair of comb-shaped electrodes including electrode fingers.

Claims

1. An acoustic wave resonator comprising:

a support substrate;

a piezoelectric substrate located on the support substrate;

a first amorphous layer that is in contact with the support substrate and is mainly composed of one or more constituent elements of the support substrate;

a second amorphous layer that is in contact with the piezoelectric substrate and the first amorphous layer, is mainly composed of one or more constituent elements of the piezoelectric substrate, and is thinner than the first amorphous layer; and

a pair of comb-shaped electrodes that is located on an opposite surface of the piezoelectric substrate from the support substrate, each of the pair of comb-shaped electrodes including electrode fingers.

2. The acoustic wave resonator according to claim 1, wherein

a thickness of the piezoelectric substrate is less than an average pitch of the electrode fingers of one of the pair of comb-shaped electrodes.

3. The acoustic wave resonator according to claim 1, wherein

the piezoelectric substrate is a monocrystalline substrate, and

the support substrate is a monocrystalline substrate, a polycrystalline substrate, or a sintered body substrate.

4. The acoustic wave resonator according to claim 3, wherein

the piezoelectric substrate is a lithium tantalate substrate or a lithium niobate substrate, and

the support substrate is a sapphire substrate, a spinel substrate, a silicon substrate, a crystal substrate, a quartz substrate, or an alumina substrate.

5. The acoustic wave resonator according to claim 4, wherein

a total atomic concentration of an element other than oxygen among the one or more constituent elements of the support substrate in the first amorphous layer is higher than a total atomic concentration of an element other than oxygen among the one or more constituent elements of the piezoelectric substrate, and

a total atomic concentration of an element other than oxygen among the one or more constituent elements of the piezoelectric substrate in the second amorphous layer is higher than a total atomic concentration of an element other than oxygen among the one or more constituent elements of the support substrate.

6. The acoustic wave resonator according to claim 1, wherein

a thickness of the second amorphous layer is equal to or less than 0.8 times a thickness of the first amorphous layer.

7. The acoustic wave resonator according to claim 1, wherein

the pair of comb-shaped electrodes excites an SH wave.

8. A filter comprising:

an acoustic wave resonator including;

a support substrate,

a piezoelectric substrate located on the support substrate,

a first amorphous layer that is in contact with the support substrate and is mainly composed of one or more constituent elements of the support substrate,

a second amorphous layer that is in contact with the piezoelectric substrate and the first amorphous layer, is mainly composed of one or more constituent elements of the piezoelectric substrate, and is thinner than the first amorphous layer, and

a pair of comb-shaped electrodes that is located on an opposite surface of the piezoelectric substrate from the support substrate, each of the pair of comb-shaped electrodes including electrode fingers.

9. A multiplexer comprising:

a filter including an acoustic wave resonator, wherein

the acoustic wave resonator includes;

a support substrate,

a piezoelectric substrate located on the support substrate,

a first amorphous layer that is in contact with the support substrate and is mainly composed of one or more constituent elements of the support substrate,

a second amorphous layer that is in contact with the piezoelectric substrate and the first amorphous layer, is mainly composed of one or more constituent elements of the piezoelectric substrate, and is thinner than the first amorphous layer, and

a pair of comb-shaped electrodes that is located on an opposite surface of the piezoelectric substrate from the support substrate, each of the pair of comb-shaped electrodes including electrode fingers.