Elastic wave device

Patent metadata

Field	Value
Publication number	US-9564873-B2
Application number	US-201414170883-A
Country	US
Kind code	B2
Filing date	Feb 3, 2014
Priority date	Aug 8, 2011
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

An elastic wave device making use of an SH plate wave propagating in LiNbO 3 substrates includes a LiNbO 3 substrate, IDT electrodes located on at least one surface of the LiNbO 3 substrate, and a support which is bonded to the LiNbO 3 substrate such that the support is located outside a region provided with the IDT electrodes and supports the LiNbO 3 substrate, wherein θ of the Euler angles (0°, θ, 0°) of the LiNbO 3 substrate ranges from about 92° to about 138° and the thickness of the LiNbO 3 substrate ranges from about 0.05λ to about 0.25λ, where λ is the wavelength determined by the pitch between electrode fingers of the IDT electrodes.

First claim

What is claimed is:

1. An elastic wave device comprising:
a LiNbO 3 substrate;
an IDT electrode located on at least one surface of the LiNbO 3 substrate; and
a support arranged on the LiNbO 3 substrate such that the support is located outside a region provided with the IDT electrode and supports the LiNbO 3 substrate; wherein
an elastic wave propagating in the LiNbO 3 substrate is an SH plate wave; and
θ of Euler angles (0°, θ, 0°) of the LiNbO 3 substrate ranges from about 92° to about 138° and a thickness of the LiNbO 3 substrate ranges from about 0.05λ to about 0.25λ, where λ is a wavelength determined by a pitch between electrode fingers of the IDT electrode.

2. The elastic wave device according to claim 1 , wherein the IDT electrode is made of a metal containing one of a plurality of metals shown in Table 1 below as a major component and have a thickness within a range specified in Table 1 depending on a type of the metal:

TABLE 1

Thickness of IDT electrode

Pt
More than 0 to 0.083λ or less

Au
More than 0 to 0.055λ or less

Cu
More than 0 to 0.11λ or less

Ni
More than 0 to 0.16λ or less

Al
More than 0 to 0.135λ or less.

3. The elastic wave device according to claim 1 , wherein the IDT electrode is made of a metal containing one of a plurality of metals shown in Table 2 below as a major component and a duty is within a range specified in Table 2 depending on a type of the metal:

TABLE 2

Duty

Pt
0.105 to 0.62

Au
0.105 to 0.585

Cu
0.11 to 0.645

Ni
0.11 to 0.655

Al
0.115 to 0.63.

4. The elastic wave device according to claim 2 , wherein the IDT electrode is made of a metal containing one of a plurality of metals shown in Table 2 below as a major component and a duty is within a range specified in Table 2 depending on a type of the metal:

TABLE 2

Duty

Pt
0.105 to 0.62

Au
0.105 to 0.585

Cu
0.11 to 0.645

Ni
0.11 to 0.655

Al
0.115 to 0.63.

5. The elastic wave device according to claim 1 , wherein the IDT electrode is located on both surfaces of the LiNbO 3 substrate, the IDT electrode is made of a metal containing one of a plurality of metals shown in Table 3 below as a major component, and a thickness of the IDT electrode is within a range specified in Table 3 depending on a type of the metal:

TABLE 3

Metal making
Thickness of single-side IDT

up electrode
electrodes

Pt
More than 0 to 0.14λ or less

Au
More than 0 to 0.067λ or less

Cu
More than 0 to 0.145λ or less

Ni
0.002λ to 0.20λ

Al
More than 0 to 0.125λ or less.

6. The elastic wave device according to claim 1 , wherein the IDT electrode is located on both surfaces of the LiNbO 3 substrate and a duty of the IDT electrode is within a range specified in Table 4 below depending on a type of a metal making up the IDT electrode:

TABLE 4

Metal making

up electrode
Duty

Pt
0.018 to 0.547

Au
0.018 to 0.523

Assignees

• Murata Manufacturing Co

Inventors

• Kadota Michio

Classifications

• H03H9/02559 Primary

  of lithium niobate or lithium-tantalate substrates · CPC title

• H03H9/02228 Primary

  Guided bulk acoustic wave devices or Lamb wave devices having interdigital transducers situated in parallel planes on either side of a piezoelectric layer · CPC title

• H03H9/25

  Constructional features of resonators using surface acoustic waves {(devices for manipulating acoustic surface waves in general G10K11/36)} · CPC title

• H03H9/02992

  Details of bus bars, contact pads or other electrical connections for finger electrodes · CPC title

• H03H9/174

  Membranes · CPC title