JP2019212981A - Acoustic wave element, splitter, and communication device - Google Patents

Abstract

To provide an acoustic wave element that can be used at a high frequency.SOLUTION: An acoustic wave element 1 has a support substrate 3, a high sound velocity layer 5 superimposed on the support substrate 3, an LT layer 7 superimposed on the high sound velocity layer 5 and formed of a single crystal of LiTaO, and an IDT electrode. The IDT electrode has a plurality of electrode fingers 27 extending parallel with each other along a top face of the LT layer 7. When a value being twice the pitch p of the plurality of electrode fingers 27 is λ, the thickness of the LT layer 7 is tp, the Euler angle of the LT layer 7 is (φ,θ,ψ), φ=Φ+180°×i, θ=Θ+180°×j, and ψ=Ψ+180°×k, wherein i, j and k are each an integer, tp is 0.05λ or more and 0.55λ or less, Ψ is 0° or more and less than 180°, and Φ and Θ are values falling within a predetermined area.SELECTED DRAWING: Figure 32

Description

  The present disclosure relates to an acoustic wave element, a duplexer, and a communication device. The elastic wave is, for example, a SAW (Surface Acoustic Wave) or a bulk wave.

2. Description of the Related Art An acoustic wave element having a piezoelectric body and an IDT (Interdigital Transducer) electrode serving as an excitation electrode positioned thereon is known (for example, Patent Documents 1 and 2). Patent Document 1 discloses a surface acoustic wave device in which a dielectric substrate, a hard dielectric layer, a piezoelectric thin film, and electrodes are stacked in order from the bottom. Patent Document 2 discloses a surface acoustic wave device in which a confinement layer, a piezoelectric body, and an IDT electrode are stacked in order from the bottom. As the piezoelectric body, lithium tantalate (LiTaO ₃ , LT) or the like is used.

JP 2004-282232 A Japanese Patent No. 5720797

  It is desired to provide an acoustic wave device, a duplexer, and a communication device that can be used at a high frequency.

An acoustic wave device according to an aspect of the present disclosure overlaps the support substrate and the support substrate, the high sound velocity layer made of a material having a higher sound speed than the material of the support substrate, and the high sound velocity layer. A piezoelectric layer made of a single crystal of LiTaO ₃ and an excitation electrode having a plurality of electrode fingers extending in parallel with each other along the upper surface of the piezoelectric layer, Twice the pitch of the electrode fingers is λ, the thickness of the piezoelectric layer is tp, the Euler angles of the piezoelectric layer are (φ, θ, ψ), φ = Φ + 180 ° × i, θ = Θ + 180 ° × j, ψ = Ψ + 180 ° × k, and i, j, and k are integers, the piezoelectric layer satisfies one of the following conditions A to E.
A: 0.05λ ≦ tp <0.15λ, and any one of the following conditions a1 to a12 is satisfied.
a1: 0 ≦ ψ <7.5 ° or 172.5 ° ≦ ψ <180 °, and Φ and Θ are in the hatched range in FIG.
a2: 7.5 ° ≦ ψ <22.5 °, and Φ and Θ are in the hatched range in FIG.
a3: 22.5 ° ≦ ψ <37.5 °, and Φ and Θ are in the hatched range in FIG.
a4: 37.5 ° ≦ ψ <52.5 °, and Φ and Θ are in the hatched range in FIG.
a5: 52.5 ° ≦ ψ <67.5 °, and Φ and Θ are in the hatched range in FIG.
a6: 67.5 ° ≦ ψ <82.5 °, and Φ and Θ are in the hatched range in FIG.
a7: 82.5 ° ≦ ψ <97.5 °, and Φ and Θ are in the hatched range in FIG.
a8: 97.5 ° ≦ ψ <112.5 °, and Φ and Θ are in the hatched range in FIG. 4B.
a9: 112.5 ° ≦ ψ <127.5 °, and Φ and Θ are in the hatched range in FIG.
a10: 127.5 ° ≦ ψ <142.5 °, and Φ and Θ are in the hatched range in FIG.
a11: 142.5 ° ≦ ψ <157.5 °, and Φ and Θ are in the hatched range in FIG.
a12: 157.5 ° ≦ ψ <172.5 °, and Φ and Θ are in the hatched range in FIG. 6B.
B: 0.15λ ≦ tp <0.25λ, and any one of the following conditions b1 to b12 is satisfied.
b1: 0 ≦ ψ <7.5 ° or 172.5 ° ≦ ψ <180 °, and Φ and Θ are in the hatched range in FIG.
b2: 7.5 ° ≦ ψ <22.5 °, and Φ and Θ are in the hatched range in FIG. 7B.
b3: 22.5 ° ≦ ψ <37.5 °, and Φ and Θ are in the hatched range in FIG.
b4: 37.5 ° ≦ ψ <52.5 °, and Φ and Θ are in the hatched range in FIG. 8B.
b5: 52.5 ° ≦ ψ <67.5 °, and Φ and Θ are in the hatched range in FIG. 9A.
b6: 67.5 ° ≦ ψ <82.5 °, and Φ and Θ are in the hatched range in FIG. 9B.
b7: 82.5 ° ≦ ψ <97.5 °, and Φ and Θ are in the hatched range in FIG.
b8: 97.5 ° ≦ ψ <112.5 °, and Φ and Θ are in the hatched range in FIG.
b9: 112.5 ° ≦ ψ <127.5 °, and Φ and Θ are in the hatched range in FIG.
b10: 127.5 ° ≦ ψ <142.5 °, and Φ and Θ are in the hatched range in FIG.
b11: 142.5 ° ≦ ψ <157.5 °, and Φ and Θ are in the hatched range in FIG.
b12: 157.5 ° ≦ ψ <172.5 °, and Φ and Θ are in the hatched range in FIG.
C: 0.25λ ≦ tp <0.35λ, and any one of the following conditions c1 to c12 is satisfied.
c1: 0 ≦ ψ <7.5 ° or 172.5 ° ≦ ψ <180 °, and Φ and Θ are in the hatched range in FIG.
c2: 7.5 ° ≦ ψ <22.5 °, and Φ and Θ are in the hatched range in FIG.
c3: 22.5 ° ≦ ψ <37.5 °, and Φ and Θ are in the hatched range in FIG.
c4: 37.5 ° ≦ ψ <52.5 °, and Φ and Θ are in the hatched range in FIG.
c5: 52.5 ° ≦ ψ <67.5 °, and Φ and Θ are in the hatched range in FIG.
c6: 67.5 ° ≦ ψ <82.5 °, and Φ and Θ are in the hatched range in FIG.
c7: 82.5 ° ≦ ψ <97.5 °, and Φ and Θ are in the hatched range in FIG.
c8: 97.5 ° ≦ ψ <112.5 °, and Φ and Θ are in the hatched range in FIG.
c9: 112.5 ° ≦ ψ <127.5 °, and Φ and Θ are in the hatched range in FIG.
c10: 127.5 ° ≦ ψ <142.5 °, and Φ and Θ are in the hatched range in FIG.
c11: 142.5 ° ≦ ψ <157.5 °, and Φ and Θ are in the hatched range in FIG.
c12: 157.5 ° ≦ ψ <172.5 °, and Φ and Θ are in the hatched range in FIG. 18B.
D: 0.35λ ≦ tp <0.45λ, and any one of the following conditions d1 to d12 is satisfied.
d1: 0 ≦ ψ <7.5 ° or 172.5 ° ≦ ψ <180 °, and Φ and Θ are in the hatched range in FIG.
d2: 7.5 ° ≦ ψ <22.5 °, and Φ and Θ are in the hatched range in FIG. 19B.
d3: 22.5 ° ≦ ψ <37.5 °, and Φ and Θ are in the hatched range in FIG.
d4: 37.5 ° ≦ ψ <52.5 °, and Φ and Θ are in the hatched range in FIG.
d5: 52.5 ° ≦ ψ <67.5 °, and Φ and Θ are in the hatched range in FIG.
d6: 67.5 ° ≦ ψ <82.5 °, and Φ and Θ are in the hatched range in FIG.
d7: 82.5 ° ≦ ψ <97.5 °, and Φ and Θ are in the hatched range in FIG.
d8: 97.5 ° ≦ ψ <112.5 °, and Φ and Θ are in the hatched range in FIG.
d9: 112.5 ° ≦ ψ <127.5 °, and Φ and Θ are in the hatched range in FIG.
d10: 127.5 ° ≦ ψ <142.5 °, and Φ and Θ are in the hatched range in FIG.
d11: 142.5 ° ≦ ψ <157.5 °, and Φ and Θ are in the hatched range in FIG.
d12: 157.5 ° ≦ ψ <172.5 °, and Φ and Θ are in the hatched range in FIG.
E: 0.45λ ≦ tp <0.55λ, and any one of the following conditions e1 to e12 is satisfied.
e1: 0 ≦ ψ <7.5 ° or 172.5 ° ≦ ψ <180 °, and Φ and Θ are in the hatched range in FIG.
e2: 7.5 ° ≦ ψ <22.5 °, and Φ and Θ are in the hatched range in FIG.
e3: 22.5 ° ≦ ψ <37.5 °, and Φ and Θ are in the hatched range in FIG.
e4: 37.5 ° ≦ ψ <52.5 °, and Φ and Θ are in the hatched range in FIG.
e5: 52.5 ° ≦ ψ <67.5 °, and Φ and Θ are in the hatched range in FIG.
e6: 67.5 ° ≦ ψ <82.5 °, and Φ and Θ are in the hatched range in FIG.
e7: 82.5 ° ≦ ψ <97.5 °, and Φ and Θ are in the hatched range in FIG.
e8: 97.5 ° ≦ ψ <112.5 °, and Φ and Θ are in the hatched range in FIG.
e9: 112.5 ° ≦ ψ <127.5 °, and Φ and Θ are in the hatched range in FIG.
e10: 127.5 ° ≦ ψ <142.5 °, and Φ and Θ are in the hatched range in FIG.
e11: 142.5 ° ≦ ψ <157.5 °, and Φ and Θ are in the hatched range in FIG.
e12: 157.5 ° ≦ ψ <172.5 °, and Φ and Θ are in the hatched range in FIG.

An acoustic wave device according to an aspect of the present disclosure overlaps the support substrate and the support substrate, the high sound velocity layer made of a material having a higher sound speed than the material of the support substrate, and the high sound velocity layer. A piezoelectric layer made of a single crystal of LiTaO ₃ and an excitation electrode having a plurality of electrode fingers extending in parallel with each other along the upper surface of the piezoelectric layer, The Euler angle of the piezoelectric layer is an angle at which the velocity of the elastic wave propagating in the direction perpendicular to the plurality of electrode fingers along the upper surface of the piezoelectric layer is 7600 m / s or more.

  In one example, the high sound velocity layer is made of a material having a longitudinal wave sound velocity of 11000 m / s or more.

  In one example, the thickness of the high sound velocity layer is 1.25λ or more, where λ is twice the pitch of the plurality of electrode fingers.

  In one example, the excitation electrode is mainly composed of Al, and the thickness of the excitation electrode is not less than 4% and not more than 7.5% of λ, where λ is twice the pitch of the plurality of electrode fingers. .

  In one example, a duplexer according to an aspect of the present disclosure includes an antenna terminal, a transmission filter that filters a transmission signal and outputs the filtered signal to the antenna terminal, and a reception filter that filters a reception signal from the antenna terminal. The transmission filter or the reception filter includes the acoustic wave element.

  In one example, a communication device according to one embodiment of the present disclosure includes an antenna, the duplexer in which the antenna terminal is connected to the antenna, and an RF-IC electrically connected to the duplexer. And have.

  According to said structure, an elastic wave element can be utilized with a high frequency.

FIG. 1A is a diagram showing the range of Φ and Θ when the LT thickness is 0.1λ and Ψ = 0 °, and FIG. 1B is the diagram of Φ when the LT thickness is 0.1λ and Ψ = 15 °. It is a figure which shows the range of Θ. FIG. 2A is a diagram showing the range of Φ and Θ when the LT thickness is 0.1λ and Ψ = 30 °, and FIG. 2B is the Φ when the LT thickness is 0.1λ and Ψ = 45 °. It is a figure which shows the range of Θ. FIG. 3A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.1λ and Ψ = 60 °, and FIG. 3B is the Φ when the LT thickness is 0.1λ and Ψ = 75 °. It is a figure which shows the range of Θ. FIG. 4A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.1λ and Ψ = 90 °, and FIG. 4B is the Φ when the LT thickness is 0.1λ and Ψ = 105 °. It is a figure which shows the range of Θ. FIG. 5A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.1λ and Ψ = 120 °, and FIG. 5B is the Φ when the LT thickness is 0.1λ and Ψ = 135 °. It is a figure which shows the range of Θ. FIG. 6A is a diagram showing the range of Φ and Θ when the LT thickness is 0.1λ and Ψ = 150 °, and FIG. 6B is the Φ when the LT thickness is 0.1λ and Ψ = 165 °. It is a figure which shows the range of Θ. FIG. 7A is a diagram showing the range of Φ and Θ when the LT thickness is 0.2λ and Ψ = 0 °, and FIG. 7B is the Φ when the LT thickness is 0.2λ and Ψ = 15 °. It is a figure which shows the range of Θ. FIG. 8A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.2λ and Ψ = 30 °, and FIG. 8B is the Φ when the LT thickness is 0.2λ and Ψ = 45 °. It is a figure which shows the range of Θ. FIG. 9A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.2λ and Ψ = 60 °, and FIG. 9B is the Φ when the LT thickness is 0.2λ and Ψ = 75 °. It is a figure which shows the range of Θ. FIG. 10A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.2λ and Ψ = 90 °, and FIG. 10B is the Φ when the LT thickness is 0.2λ and Ψ = 105 °. It is a figure which shows the range of Θ. FIG. 11A is a diagram showing the range of Φ and Θ when the LT thickness is 0.2λ and Ψ = 120 °, and FIG. 11B is the Φ when the LT thickness is 0.2λ and Ψ = 135 °. It is a figure which shows the range of Θ. FIG. 12A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.2λ and Ψ = 150 °, and FIG. 12B is the Φ when the LT thickness is 0.2λ and Ψ = 165 °. It is a figure which shows the range of Θ. FIG. 13A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.3λ and Ψ = 0 °, and FIG. 13B is the Φ when the LT thickness is 0.3λ and Ψ = 15 °. It is a figure which shows the range of Θ. FIG. 14A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.3λ and Ψ = 30 °, and FIG. 14B is the Φ when the LT thickness is 0.3λ and Ψ = 45 °. It is a figure which shows the range of Θ. FIG. 15A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.3λ and Ψ = 60 °, and FIG. 15B is the Φ when the LT thickness is 0.3λ and Ψ = 75 °. It is a figure which shows the range of Θ. FIG. 16A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.3λ and Ψ = 90 °, and FIG. 16B is the Φ when the LT thickness is 0.3λ and Ψ = 105 °. It is a figure which shows the range of Θ. FIG. 17A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.3λ and Ψ = 120 °, and FIG. 17B is the Φ when the LT thickness is 0.3λ and Ψ = 135 °. It is a figure which shows the range of Θ. FIG. 18A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.3λ and Ψ = 150 °, and FIG. 18B is the Φ when the LT thickness is 0.3λ and Ψ = 165 °. It is a figure which shows the range of Θ. FIG. 19A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.4λ and Ψ = 0 °, and FIG. 19B is the Φ when the LT thickness is 0.4λ and Ψ = 15 °. It is a figure which shows the range of Θ. FIG. 20A is a diagram showing the range of Φ and Θ when the LT thickness is 0.4λ and Ψ = 30 °, and FIG. 20B is the Φ when the LT thickness is 0.4λ and Ψ = 45 °. It is a figure which shows the range of Θ. FIG. 21 (a) is a diagram showing the range of Φ and Θ when the LT thickness is 0.4λ and Ψ = 60 °, and FIG. 21 (b) is the Φ when the LT thickness is 0.4λ and Ψ = 75 °. It is a figure which shows the range of Θ. FIG. 22A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.4λ and Ψ = 90 °, and FIG. 22B is the Φ when the LT thickness is 0.4λ and Ψ = 105 °. It is a figure which shows the range of Θ. FIG. 23A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.4λ and Ψ = 120 °, and FIG. 23B is the Φ when the LT thickness is 0.4λ and Ψ = 135 °. It is a figure which shows the range of Θ. FIG. 24A shows the range of Φ and Θ when the LT thickness is 0.4λ and Ψ = 150 °, and FIG. 24B shows the Φ when the LT thickness is 0.4λ and Ψ = 165 °. It is a figure which shows the range of Θ. FIG. 25A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.5λ and Ψ = 0 °, and FIG. 25B is the Φ when the LT thickness is 0.5λ and Ψ = 15 °. It is a figure which shows the range of Θ. FIG. 26A is a diagram showing the range of Φ and Θ when the LT thickness is 0.5λ and Ψ = 30 °, and FIG. 26B is the Φ when the LT thickness is 0.5λ and Ψ = 45 °. It is a figure which shows the range of Θ. FIG. 27A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.5λ and Ψ = 60 °, and FIG. 27B is the Φ when the LT thickness is 0.5λ and Ψ = 75 °. It is a figure which shows the range of Θ. FIG. 28 (a) is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.5λ and Ψ = 90 °, and FIG. 28 (b) is the Φ when the LT thickness is 0.5λ and Ψ = 105 °. It is a figure which shows the range of Θ. FIG. 29A is a diagram showing the ranges of Φ and Θ when the LT thickness is 0.5λ and Ψ = 120 °, and FIG. 29B is the Φ when the LT thickness is 0.5λ and Ψ = 135 °. It is a figure which shows the range of Θ. FIG. 30A is a diagram showing the range of Φ and Θ when the LT thickness is 0.5λ and Ψ = 150 °, and FIG. 30B is the Φ when the LT thickness is 0.5λ and Ψ = 165 °. It is a figure which shows the range of Θ. It is a top view which shows the structure of the elastic wave element which concerns on embodiment. It is sectional drawing in the XXXII-XXXII line | wire of FIG. 33 (a) and 33 (b) are diagrams showing an example of impedance characteristics when the high sound velocity layer is diamond. 34 (a) and 34 (b) are diagrams showing an example of impedance characteristics when the high sound velocity layer is boron nitride. FIGS. 35A and 35B are diagrams showing an example of impedance characteristics when the high sound velocity layer is diamond-like carbon. It is a schematic diagram which shows the meaning of the kind of hatching pattern in Fig.1 (a)-FIG.30 (b). FIG. 37A is a diagram showing the effect of the thickness of the conductive layer on the frequency difference Δf, and FIG. 37B is a diagram showing the effect of the thickness of the conductive layer on the phase of impedance. It is a figure which shows the influence which the thickness of a high-sonic velocity layer has on the phase of an impedance. It is a circuit diagram explaining the branching filter concerning an embodiment. It is the schematic explaining the communication apparatus which concerns on embodiment.

  Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. Note that the drawings used in the following description are schematic, and the dimensional ratios and the like on the drawings do not necessarily match the actual ones.

  In the acoustic wave device according to the present disclosure, any direction may be upward or downward. For convenience, an orthogonal coordinate system including a D1 axis, a D2 axis, and a D3 axis is defined below. In some cases, terms such as the upper surface or the lower surface are used with the positive side of the D3 axis as the upper side. The D1 axis is defined to be parallel to the propagation direction of the elastic wave propagating along the upper surface of the LT layer described later, and the D2 axis is defined to be parallel to the upper surface of the LT layer and orthogonal to the D1 axis. The D3 axis is defined to be orthogonal to the upper surface of the LT layer.

[Overall configuration of elastic wave device]
FIG. 31 is a plan view showing a configuration of a main part of the acoustic wave device 1. 32 is a cross-sectional view taken along line XXXII-XXXII in FIG.

  The acoustic wave element 1 includes, for example, a composite substrate 2 and a conductive layer 9 located on the composite substrate 2. As shown in FIG. 32, the composite substrate 2 includes a support substrate 3, a high sound velocity layer 5 that overlaps the support substrate 3, and an LT layer 7 that overlaps the high sound velocity layer 5. Each layer (3, 5, 7, and 9) has a substantially constant thickness in the plane, for example.

  In the elastic wave element 1, an elastic wave propagating through the LT layer 7 is excited by applying a voltage to the electrode portion of the conductive layer 9. The acoustic wave element 1 constitutes, for example, a resonator and / or a filter that uses this acoustic wave. The high acoustic velocity layer 5 contributes to, for example, reflecting the elastic wave and confining the energy of the elastic wave in the LT layer 7. The support substrate 3 contributes to reinforcing the strength of the high sound velocity layer 5 and the LT layer 7, for example. Note that the types of elastic waves used (including not only the distinction between SAW and bulk waves but also the distinction between modes) may differ depending on the specific configuration of each of these layers.

  In the following description, when expressing the length, the wavelength λ of the elastic wave may be used as the reference length. The wavelength λ used as the reference length is not the wavelength of the actually propagated elastic wave, but is twice the pitch p of the electrode fingers 27 described later.

[Support substrate]
The material of the support substrate 3 may be set as appropriate. For example, the material of the support substrate 3 is, for example, a semiconductor or an insulating material. The semiconductor is, for example, silicon (Si). The insulating material is, for example, resin or ceramic. The support substrate 3 may be configured by laminating a plurality of layers made of different materials.

  The support substrate 3 may be made of a material having a lower coefficient of thermal expansion than the LT layer 7 or the like. In this case, for example, the risk that the frequency characteristics of the acoustic wave device 1 will change due to temperature changes can be reduced. Examples of such a material include a semiconductor such as silicon, a single crystal such as sapphire, and a ceramic such as an aluminum oxide sintered body.

  The thickness of the support substrate 3 may also be set as appropriate. For example, the support substrate 3 is thicker than the LT layer 7 and the high sound velocity layer 5. As an example, the thickness of the support substrate 3 is not less than 100 μm and not more than 300 μm, or not less than 30 times and not more than 3000 times the thickness of the LT layer 7.

[High sound velocity layer]
The high sound velocity layer 5 is made of, for example, a material having a sound velocity higher than that of the LT layer 7. Thereby, for example, leakage of elastic waves propagating through the LT layer 7 to the high sound velocity layer 5 can be reduced. The sound velocity here is assumed to be a sound velocity c represented by c = √ (M / ρ), where M is the elastic modulus of the material and ρ is the density of the material. When there is anisotropy with respect to the elastic modulus (for example, silicon, sapphire, etc.), the sound speed is calculated using the elastic constant, and the sound speed of the isotropic material is calculated or the approximate number is calculated. As the rate M, for example, Young's modulus E may be used. Here, the sound velocity c may be a longitudinal wave sound velocity.

  The high sound velocity layer 5 is provided to confine elastic waves propagating through the LT layer 7 in the LT layer 7. Therefore, basically, it is not assumed that elastic waves leak to the support substrate 3 side. Therefore, the material of the support substrate 3 may be lower or higher than the high sound velocity layer 5 or equivalent, but the sound velocity is higher than that of the LT layer 7 and lower than that of the high sound velocity layer 5. Good.

Here, as described later, the sound speed of the LT layer 7 is 7600 m / s or more. For example, when the material of the support substrate 3 is silicon (E: about 185 GPa, ρ: about 2.33 g / cm ³ , c: 8910 m / s), diamond (E: About 910 GPa, ρ: about 3.52 g / cm ³ , c: about 16078 m / s), DLC (diamond-like carbon) (E: about 785 GPa, ρ: about 2.0 g / cm ³ , c: about 198111 m / s) Boron nitride (E: about 660 GPa, ρ: about 3.5 g / cm ³ , c: about 13771 m / s), silicon carbide (E: about 440 GPa, ρ: about 3.1 g / cm ³ , c: about 11800 m / s) s) and sapphire (E: about 470 GPa (maximum value), ρ: about 3.98 g / cm ³ , c: about 10867 m / s).

  As understood from the above examples, the sound velocity c of the longitudinal wave of the support substrate 3 is highly likely to be about 9000 m / s on average and about 10900 m / s at maximum. Therefore, the material of the high sound velocity layer 5 may be a material having a longitudinal wave sound velocity c of 11000 m / s or more, or 15000 m / s or more, for example. Further, if the acoustic velocity c of the longitudinal wave is 11000 m / s or more, various elastic waves propagating through the LT layer 7 are easily confined. Further, if the longitudinal wave sound velocity c is 11000 m / s or more, a sufficient margin can be taken for both the cutoff frequency and the loss can be suppressed.

  The thickness th of the high acoustic velocity layer 5 may be appropriately set according to the specifications required for the acoustic wave element 1, the material of the high acoustic velocity layer 5, and the like. For example, the thickness th is 0.75λ or more, or 1.25λ or more. Within this range, for example, the effect of confining the elastic wave propagating through the LT layer 7 can be sufficiently obtained. The upper limit of the thickness th is not particularly limited from the viewpoint of the effect of confining the elastic wave propagating through the LT layer 7. However, the upper limit value may be set from the viewpoint of facilitating the manufacture and handling of the composite substrate 2 and obtaining the effect of compensation of the temperature characteristics by the support substrate 3. For example, the thickness th is 5λ or less or 3λ or less.

  The width of the high sound velocity layer 5 and the width of the support substrate 3 may be the same or different (the support substrate 3 may be wider than the high sound velocity layer 5). In the latter case, a part of the conductor pattern (for example, an input or output terminal) on the composite substrate 2 may be provided on the support substrate 3 instead of on the LT layer 7.

  The high sound velocity layer 5 and the support substrate 3 may be directly overlapped, or may be indirectly overlapped via a mediation layer (not shown). The mediation layer contributes to, for example, adhesion between the high sound velocity layer 5 and the support substrate 3 and / or prevention of diffusion. The mediation layer may also affect the acoustic interaction between them.

  When the high sonic velocity layer 5 and the support substrate 3 are directly overlapped, for example, the lower surface of the high sonic velocity layer 5 and the upper surface of the support substrate 3 are activated by plasma or neutral particle beam, and both surfaces are directly applied. Can be pasted together. Further, for example, a material for forming the high acoustic velocity layer 5 may be formed on the support substrate 3 by a thin film forming method such as CVD (Chemical Vapor Deposition).

When a mediation layer is provided between the high acoustic velocity layer 5 and the support substrate 3, the mediation layer may be an organic material or an inorganic material. Examples of the organic material include a resin such as a thermosetting resin. Examples of the inorganic material include SiO ₂ , Si ₃ N ₄ , and AlN. Further, a laminated body in which thin layers made of a plurality of different materials are laminated may be used as an intermediate layer.

[LT layer]
The LT layer 7 is composed of a single crystal of lithium tantalate (LiTaO ₃ , LT). The cut angle of the LT layer 7 will be described later. The thickness tp of the LT layer 7 is relatively thin and is, for example, 0.05λ or more and 0.55λ or less with reference to λ described later. From another viewpoint, for example, the LT layer 7 is thinner than the high sound velocity layer 5. More specifically, the thickness tp of the LT layer 7 is, for example, ½ or less of the thickness th of the high sound velocity layer 5.

  The LT layer 7 and the high sound velocity layer 5 may directly overlap each other, or may indirectly overlap via a mediation layer (not shown). The mediation layer contributes to, for example, adhesion between the LT layer 7 and the high sound velocity layer 5 and / or prevention of diffusion. The mediation layer is made thinner than the LT layer 7 and the high sound velocity layer 5, for example, 0.01λ or less. By reducing the thickness in this way, the influence of the mediation layer on the elastic wave propagating through the LT layer 7 is negligible.

  When the LT layer 7 and the high sound velocity layer 5 directly overlap, for example, the lower surface of the LT layer 7 and the upper surface of the high sound velocity layer 5 are activated by plasma or neutral particle beam, and both surfaces are directly coated. Can be pasted together. Further, for example, a material to be the LT layer 7 may be formed on the high sound velocity layer 5 by a thin film forming method such as CVD.

When a mediation layer is provided between the LT layer 7 and the high sound velocity layer 5, the mediation layer may be an organic material or an inorganic material. Examples of the organic material include a resin such as a thermosetting resin. Examples of the inorganic material include SiO ₂ , Si ₃ N ₄ , and AlN. Further, a laminated body in which thin layers made of a plurality of different materials are laminated may be used as an intermediate layer.

  The area of the LT layer 7 and the area of the high sound velocity layer 5 may be the same or different (the high sound velocity layer 5 may be wider than the LT layer 7). In the latter case, a part of the conductor pattern on the composite substrate 2 (for example, an input or output terminal) may be provided on the high sound velocity layer 5 instead of on the LT layer 7.

[Conductive layer]
The conductive layer 9 is made of metal, for example. The metal may be of an appropriate type, for example, aluminum (Al) or an alloy containing Al as a main component (Al alloy). The Al alloy is, for example, an aluminum-copper (Cu) alloy. The conductive layer 9 may be composed of a plurality of metal layers. For example, a relatively thin layer made of titanium (Ti) may be provided between Al or Al alloy and the LT layer 7 in order to reinforce these bondability.

  The thickness te of the conductive layer 9 may be appropriately set according to specifications required for the acoustic wave element 1, the material of the conductive layer 9, and the like. For example, the thickness te may be 2% to 10% of the wavelength λ, or 4% to 7.5%.

  In the example of FIG. 31, the conductive layer 9 is formed so as to constitute the resonator 15. The resonator 15 is configured as a so-called 1-port acoustic wave resonator. When an electric signal having a predetermined frequency is input from one of the terminals 17A and 17B, which is conceptually and schematically illustrated, the resonator 15 resonates. The resulting signal can be output from the other of terminals 17A and 17B.

  The conductive layer 9 (resonator 15) includes, for example, an IDT electrode 19 and a pair of reflectors 21 located on both sides of the IDT electrode 19. Although the resonator 15 is constituted by the composite substrate 2 and the conductive layer 9, for convenience of explanation, the resonator 15 is an electrode portion (one of the conductive layers 9) composed of an IDT electrode 19 and a pair of reflectors 21. Part).

  The IDT electrode 19 includes a pair of comb electrodes 23. In addition, in order to improve visibility, one comb-tooth electrode 23 is hatched. Each comb electrode 23 includes, for example, a bus bar 25, a plurality of electrode fingers 27 extending in parallel from the bus bar 25, and a dummy electrode 29 protruding from the bus bar 25 between the plurality of electrode fingers 27. The pair of comb-tooth electrodes 23 are arranged so that the plurality of electrode fingers 27 mesh with each other (intersect).

  For example, the bus bar 25 is formed in an elongated shape extending in a straight line in the propagation direction (D1-axis direction) of the elastic wave with a substantially constant width. The pair of bus bars 25 oppose each other in a direction (D2 axis direction) orthogonal to the propagation direction of the elastic wave. Note that the bus bar 25 may change in width or may be inclined with respect to the propagation direction of the elastic wave.

  Each electrode finger 27 is, for example, formed in an elongated shape extending in a straight line in a direction (D2 axis direction) having a substantially constant width and perpendicular to the propagation direction of the elastic wave. In each comb electrode 23, the plurality of electrode fingers 27 are arranged in the propagation direction of the elastic wave. The plurality of electrode fingers 27 of one comb-tooth electrode 23 and the plurality of electrode fingers 27 of the other comb-tooth electrode 23 are basically arranged alternately.

  The pitch p of the plurality of electrode fingers 27 (for example, the distance between the centers of two electrode fingers 27 adjacent to each other) is basically constant in the IDT electrode 19. A part of the IDT electrode 19 may be provided with a narrow pitch part where the pitch p is narrower than the other most part, or a wide pitch part where the pitch p is wider than the other most part.

  In the following description, when the pitch p is referred to, unless otherwise specified, the pitch of a portion (most part of the plurality of electrode fingers 27) excluding a specific portion such as the narrow pitch portion or the wide pitch portion as described above. It shall be said. Further, in the case where the pitch is changed in most of the plurality of electrode fingers 27 excluding the peculiar part, the average value of the pitch of the most plurality of electrode fingers 27 is set as the value of the pitch p. May be used.

  Further, as already described, the wavelength λ used as the length reference in the present disclosure is twice the pitch p. The pitch p at this time is also the most pitch or the average value excluding the singular part, as described above.

  The number of electrode fingers 27 may be appropriately set according to the electrical characteristics required for the resonator 15. Since FIG. 31 is a schematic diagram, the number of electrode fingers 27 is small. Actually, more electrode fingers 27 than shown may be arranged. The same applies to the strip electrode 33 of the reflector 21 described later.

  The lengths of the plurality of electrode fingers 27 are, for example, equal to each other. The IDT electrode 19 may be subjected to so-called apodization in which the lengths of the plurality of electrode fingers 27 (cross width in another viewpoint) change according to the position in the propagation direction. The length and width of the electrode finger 27 may be appropriately set according to required electrical characteristics and the like.

  For example, the dummy electrode 29 is formed in a shape that protrudes in a direction orthogonal to the propagation direction of the elastic wave with a substantially constant width. The width is equal to the width of the electrode finger 27, for example. The plurality of dummy electrodes 29 are arranged at the same pitch as the plurality of electrode fingers 27, and the tip of the dummy electrode 29 of one comb-tooth electrode 23 is the tip of the electrode finger 27 of the other comb-tooth electrode 23. And facing through the gap. The IDT electrode 19 may not include the dummy electrode 29.

  The pair of reflectors 21 are located on both sides of the plurality of IDT electrodes 19 in the propagation direction of the elastic wave. Each reflector 21 may be in an electrically floating state, for example, or may be provided with a reference potential. Each reflector 21 is formed in a lattice shape, for example. That is, the reflector 21 includes a pair of bus bars 31 facing each other and a plurality of strip electrodes 33 extending between the pair of bus bars 31. The pitch of the plurality of strip electrodes 33 and the pitch between the electrode fingers 27 and the strip electrodes 33 adjacent to each other are basically the same as the pitch of the plurality of electrode fingers 27.

Although not particularly illustrated, the upper surface of the LT layer 7 may be covered with a protective film made of SiO ₂ , Si ₃ N ₄ or the like from above the conductive layer 9. The protective film may be a multi-layered laminate made of these materials. The protective film may be merely for suppressing corrosion of the conductive layer 9 or may contribute to temperature compensation. In the case where a protective film is provided, an additional film made of an insulator or metal may be provided on the upper or lower surface of the IDT electrode 19 and the reflector 21 in order to improve the reflection coefficient of the elastic wave.

  The configuration shown in FIGS. 31 and 32 may be appropriately packaged. For example, the package may be one in which the configuration shown in the figure is mounted on a substrate (not shown) so that the upper surface of the LT layer 7 faces with a gap, and resin-sealed from above. A wafer-level package type in which a box-type cover is provided on the LT layer 7 may be used. The lower part of the cover may be located on the LT layer 7, may be located on the high sound velocity layer 5 on the assumption that the high sound velocity layer 5 is wider than the LT layer 7, or the support substrate 3. May be located on the support substrate 3 on the premise that it is wider than the high sound velocity layer 5.

[Use of special Euler angles]
When a voltage is applied to the pair of comb electrodes 23, a voltage is applied to the LT layer 7 by the plurality of electrode fingers 27, and the LT layer 7 that is a piezoelectric body vibrates. Thereby, the elastic wave propagating in the D1 axis direction is excited. The elastic wave is reflected by the plurality of electrode fingers 27. Usually, a standing wave is generated in which the pitch p of the plurality of electrode fingers 27 is approximately a half wavelength (λ / 2). An electrical signal generated in the LT layer 7 by the standing wave is extracted by the plurality of electrode fingers 27. Based on such a principle, the acoustic wave element 1 generally functions as a resonator having a resonance frequency that is an elastic wave frequency having a pitch p of half wavelength.

As will be appreciated from the above, the resonance frequency fr, when the velocity of the acoustic wave _{c a,} basically defined by _{fr = c a / (2p)} . Speed c _a is different materials of the piezoelectric (LT layer 7 in this embodiment), the type of cut angle and acoustic waves. In general, when the piezoelectric body is LT, for example, SAW having _a speed ca of 3200 m / s to 4200 m / s is used. Therefore, for example, when the pitch p is 1 μm, the resonance frequency is 1.6 GHz to 2.1 GHz. Incidentally, the speed c _a shows a velocity of acoustic waves in the LT layer.

When the LT layer 7 is formed on the high sound velocity layer 5 having a relatively high sound velocity and the Euler angle (cut angle) of the LT layer 7 is set to a special angle, the inventor of the present application has a resonance frequency fr higher than that of the prior art. It has been found that a resonance phenomenon can be caused. For example, it is possible to produce a resonance phenomenon in resonance frequency fr velocity _{c a} was calculated back from the resonance frequency fr and the pitch p is 7600m / s or more. As a result, for example, even if the pitch p is 1 μm or more, a resonance frequency fr of 3.8 GHz or more can be realized.

  This is because by providing the high sound velocity layer 5, leakage of elastic waves corresponding to a relatively high resonance frequency fr to the support substrate 3 can be suppressed, and the elastic waves can be confined in the LT layer 7. . The elastic wave corresponding to the relatively high resonance frequency fr here is an elastic wave having a high propagation speed, and the propagation speed is the same as that of the conventional wave, and has a higher order than an elastic wave having a pitch p of half wavelength ( For example, an elastic wave having a short wavelength is used.

  The Euler angles (φ, θ, ψ) are described in a confirming manner. The method of displaying the plane orientation of the piezoelectric body by the Euler angle is defined, for example, in Japanese Industrial Standard (JIS) C6760 “Single Crystal Wafer for Surface Acoustic Wave Device—Specification and Measurement Method”. Euler angle display may conform to this rule.

  An outline of Euler angle display using the D1 axis, the D2 axis, and the D3 axis of the present disclosure will be described as follows. A coordinate system (X ′, Y ′, Z) is obtained by rotating the crystal axes (X, Y, Z) by φ around the Z axis and in the right-handed direction. A coordinate system (X ′, Y ″, D3) is obtained by rotating the coordinate system (X ′, Y ′, Z) by θ rotation around the X ′ axis and in the right-handed direction. The coordinate system (D1, D2, D3) is obtained by rotating Y ″, D3) about the D3 axis and rotating in the right-hand screw direction. As described above, the D1 axis is an axis parallel to the propagation direction of the elastic wave propagating along the upper surface of the LT layer 7. The D2 axis is an axis parallel to the upper surface of the LT layer 7 and orthogonal to the D1 axis. The D3 axis is an axis orthogonal to the upper surface of the LT layer 7.

From the symmetry of LT, Euler angles (φ, θ, ψ) can be expressed as follows.
φ = Φ + 180 ° × i,
θ = Θ + 180 ° × j, and ψ = Ψ + 180 ° × k
Here, each of Φ, Θ, and Ψ is an angle of 0 ° to 180 °. Each of i, j, and k is a negative, zero, or positive integer. From another viewpoint, the Euler angles (Φ, Θ, ψ) are one of a plurality of sets of Euler angles (φ, θ, ψ) that are equivalent to each other with respect to the characteristics of the LT. In the following description, only the Euler angles (Φ, Θ, ψ) may be mentioned on behalf of plural sets of Euler angles (φ, θ, ψ). In other words, in the following description, Euler angles (Φ, Θ, ψ) may be read as equivalent Euler angles (φ, θ, ψ).

[Example of resonance characteristics]
As described above, by forming the high sound velocity layer 5 under the LT layer 7 and setting the Euler angle of the LT layer 7 to a special angle, a resonance phenomenon can be generated at a relatively high resonance frequency fr. it can. This was confirmed by simulation calculation.

  Fig.33 (a)-FIG.35 (b) are figures which show an example of the calculation result. FIG. 33A and FIG. 33B show the characteristics of the resonator 15 when diamond is used as the material of the high sound velocity layer 5. FIG. 34A and FIG. 34B show the characteristics of the resonator 15 when boron nitride (BN) is used as the material of the high acoustic velocity layer 5. FIGS. 35A and 35B show the characteristics of the resonator 15 when DLC is used as the material of the high sound velocity layer 5.

  In FIG. 33A to FIG. 35B, the horizontal axis indicates the frequency (MHz). In FIG. 33A, FIG. 34A, and FIG. 35A, the vertical axis indicates the absolute value (Ω) of the impedance. 33 (b), 34 (b), and 35 (b), the vertical axis represents the impedance phase (°).

  As shown in FIG. 33A, in the resonator 15, a resonance point (fr) where the impedance becomes a minimum value and an anti-resonance point (fa) where the impedance becomes a maximum value appear. By using such a change in impedance with respect to frequency, for example, a filter that allows only a signal having a specific frequency to pass can be configured.

  Here, the frequency at which the resonance point appears is the resonance frequency fr, and the frequency at which the anti-resonance point appears is the anti-resonance frequency fa. As described above, the resonance frequency fr is generally defined roughly by the pitch p and the propagation speed of the elastic wave. The anti-resonance frequency fa is generally defined by the resonance frequency fr and the capacitance of the IDT electrode 19 in general. In the resonator 15, for example, the antiresonance frequency fa is higher than the resonance frequency fr.

  In general, there is one elastic wave that is the main factor of the impedance change at the resonance point and the anti-resonance point, and the impedance change due to other elastic waves is treated as, for example, spurious. However, in this embodiment, the elastic wave that causes the resonance point and the elastic wave that causes the anti-resonance point may be different from each other.

  A difference between the resonance frequency fr and the antiresonance frequency fa is represented by Δf. By securing this frequency difference Δf with a certain size (width), for example, in a filter using the resonator 15, the width of the pass band through which the signal passes can be secured.

  The impedance phase indicates that the loss of the SAW resonator is smaller as it is closer to 90 ° between the resonance frequency fr and the antiresonance frequency fa, and on the outer side, the loss of the SAW resonator is smaller as it is closer to −90 °. Indicates that the loss is small.

  In FIGS. 33 (a) to 35 (b), the resonance point and the antiresonance point clearly appear when the high acoustic velocity layer 5 is any of diamond, BN, and DLC. Further, the frequency difference Δf is also secured. For example, Δf is 55 MHz to 75 MHz. Further, when attention is paid to the impedance phase, the loss is sufficiently small. Therefore, for example, in any case, characteristics sufficient to configure a filter by the resonator 15 are shown.

Here, in any of the illustrated cases, the pitch p is 1 μm. On the other hand, in the illustrated case, the resonance frequency fr is in the range of 4100 MHz to 4500 MHz. When calculated back speed _{c a} by fr × 2p, velocity _{c a} is a value of the range 8200M / s or more 9000 m / s. The speed is higher than the speed of SAW (3200 m / s to 4200 m / s) conventionally used in the LT substrate.

  As described above, by forming the high sound velocity layer 5 under the LT layer 7 and setting the Euler angle of the LT layer 7 to a special angle, a resonance phenomenon can be generated at a relatively high resonance frequency fr. Can be confirmed by simulation calculation.

  FIG. 33A to FIG. 35B show some of the cases in which the characteristics of the resonator 15 are relatively good among the many cases in which the inventors of the present invention investigated the characteristics of the resonator 15 by simulation calculation. ing. The conditions such as Euler angles used in the simulation calculations of FIGS. 33 (a) to 35 (b) are shown below. Similarly, Euler angles at which good characteristics are obtained are also exemplified. The LT layer 7 is formed at Euler angles (Φ ± 5 °, Θ ± 5 °, ψ ± 5 °) in the range of ± 5 ° with respect to the Euler angles (Φ, Θ, ψ) exemplified below. Also good.

The simulation conditions common to a plurality of cases are as follows.
IDT electrode:
Material: Al
Thickness: 4% of λ
Pitch p: 1 μm
LT layer thickness tp: 0.3λ (however, only “other examples” when the high sound velocity layer is BN is 0.35λ)
The thickness th of the high sound velocity layer 5 was assumed to be sufficiently thick. Further, the conditions that are not particularly mentioned are common to the cases of FIGS. 33 (a) to 35 (b).

The Euler angles (Φ, Θ, Ψ) by material of the high acoustic velocity layer 5 are as follows. In the following, “/” means “or”.
When the supersonic layer is diamond:
Example shown: (90, 90, 110), (30/150, 90, 70)
Other examples: (85/95, 90, 125), (25/35, 90, 55), (145/155, 90, 55)
When the high sound velocity layer is BN:
Example shown: (90, 90, 110), (30/150, 90, 70)
Other examples: (90, 90, 125), (30/150, 90, 55)
When the high sound velocity layer is DLC:
Example shown: (90, 90, 120), (30/150, 90, 60)
Other examples: (90, 90, 115), (30/150, 90, 65)

  When the Euler angles of the LT layer 7 exemplified above are compared between cases where the materials of the high sound velocity layer 5 are different from each other, the angles are substantially the same. From this, it can be seen that the Euler angle at which the resonance phenomenon can be generated at a relatively high resonance frequency fr can be generally specified regardless of the material of the high sound velocity layer 5.

[Special Euler angle range]
For a plurality of cases where the Euler angles and the like of the LT layer 7 were varied, the characteristics of the resonator 15 were obtained by simulation calculation in the same manner as described above. Based on the result, a range of Euler angles that can cause a resonance phenomenon at a relatively high resonance frequency fr was specified. Specifically, it is as follows.

(Simulation variables)
As described below, various values were set for the parameters that define the resonator 15, and a plurality of simulation cases were set.
-Thickness of LT layer It was made to differ for every 0.1 (lambda) in the range of 0.1 (lambda) -0.5 (lambda). That is, five values were set for the thickness of the LT layer.
-Φ, Θ, and Ψ were varied from 0 ° to 165 ° every 15 °. That is, 11 types of values were set for each of Φ, Θ, and ψ. Note that the case of 0 ° and the case of 180 ° are equivalent due to the symmetry of the LT layer 7, and in the following, simulation results may be shown in the range of 0 ° to 180 °.
As described above, the 8640 (= 5 × 12 × 12 × 12) case was set.

(Common simulation conditions)
The simulation conditions of the above 8640 cases are the same except for the above variables (the thickness tp of the LT layer 7 and the Euler angles (Φ, Θ, Ψ)). The simulation conditions are shown below.
IDT electrode:
Material: Al
Thickness: 4% of λ
Pitch: 1 μm
Number of electrode fingers: 100 Duty: 0.5
Intersection width: 40λ
Reflector Material: Same as IDT electrode Thickness: Same as IDT electrode Number of strip electrodes: 30 Material of high sound velocity layer: Diamond Note that the support substrate 3 was treated as PML (Perfectly Matched Layer). The duty is a ratio (w / p) between the width (w) of the electrode finger 27 and the pitch p. The crossing width is the overlapping amount of the electrode fingers 27 adjacent to each other when viewed in the D1 axis direction (the distance in the D2 axis direction between the tips of the electrode fingers 27 adjacent to each other).

(Method for extracting simulation cases)
Cases in which the simulation result satisfies a certain extraction condition were extracted from 8640 cases. The extraction conditions are as follows.
(A) The value obtained by multiplying the resonance frequency fr obtained by the simulation calculation by the pitch p (1 μm in this case) of the simulation condition exceeds 3,800. That is, the speed _{c a} calculated from fr × λ (λ = 2p) exceeds 7600m / s.
(B) The frequency difference Δf obtained by the simulation calculation is 20 MHz or more. However, for the accuracy of calculation, depending on the case, the condition is that the value is 20 MHz or more and 30 MHz or less (the extraction condition is stricter than 20 MHz).

  If fr × λ is 7600 m / s or more, for example, it can be clearly distinguished from the conventional relationship between the pitch p and the resonance frequency fr. In addition, if the frequency difference Δf is 20 MHz or more, for example, the frequency difference Δf can be ensured with a sufficient size for constituting a filter by the resonator 15.

(Simulation case extraction result)
Fig.1 (a)-FIG.30 (b) are figures which show the simulation case extracted according to the extraction conditions mentioned above. From another viewpoint, it is a diagram illustrating the Euler angle of the LT layer 7 that can cause a resonance phenomenon at a relatively high resonance frequency fr. In other words, it is a diagram illustrating an Euler angle in the resonator 15 according to the present embodiment.

  FIG. 1A to FIG. 6B show results when the thickness tp of the LT layer 7 is 0.1λ. FIGS. 7A to 12B show the results when the LT layer 7 has a thickness tp of 0.2λ. FIG. 13A to FIG. 18B show results when the LT layer 7 has a thickness tp of 0.3λ. FIGS. 19A to 24B show the results when the LT layer 7 has a thickness tp of 0.4λ. FIG. 25A to FIG. 30B show the results when the LT layer 7 has a thickness tp of 0.5λ.

  As shown in the upper part of these figures, the angle of Ψ is shown, and each figure shows a simulation result for each value of Ψ (at intervals of 15 °). Specifically, it is as follows. FIG. 1 (a): Ψ = 0 °, FIG. 1 (b): Ψ = 15 °, FIG. 2 (a): Ψ = 30 °, FIG. 2 (b): Ψ = 45 °, FIG. 3 (a): FIG. 3B: Ψ = 75 °, FIG. 4A: Ψ = 90 °, FIG. 4B: Ψ = 105 °, FIG. 5A: Ψ = 120 °, FIG. 5 (b): Ψ = 135 °, FIG. 6 (a): Ψ = 150 °, FIG. 6 (b): Ψ = 165 °, FIG. 7 (a): Ψ = 0 °, FIG. 7 (b): Ψ = 15 °, FIG. 8 (a): Ψ = 30 °, FIG. 8 (b): Ψ = 45 °, FIG. 9 (a): Ψ = 60 °, FIG. 9 (b): Ψ = 75 °, FIG. (A): Ψ = 90 °, FIG. 10 (b): Ψ = 105 °, FIG. 11 (a): Ψ = 120 °, FIG. 11 (b): Ψ = 135 °, FIG. 12 (a): Ψ = 150 °, FIG. 12 (b): ψ = 165 °, FIG. 13 (a): ψ = 0 °, FIG. 13 (b): ψ = 15 °, FIG. 14 (a): ψ = 30 °, FIG. b): Ψ = 45 ° 15 (a): Ψ = 60 °, FIG. 15 (b): Ψ = 75 °, FIG. 16 (a): Ψ = 90 °, FIG. 16 (b): Ψ = 105 °, FIG. 17 (a). : Ψ = 120 °, FIG. 17 (b): Ψ = 135 °, FIG. 18 (a): Ψ = 150 °, FIG. 18 (b): Ψ = 165 °, FIG. 19 (a): Ψ = 0 °, FIG. 19 (b): Ψ = 15 °, FIG. 20 (a): Ψ = 30 °, FIG. 20 (b): Ψ = 45 °, FIG. 21 (a): Ψ = 60 °, FIG. 21 (b): Ψ = 75 °, FIG. 22A: Ψ = 90 °, FIG. 22B: Ψ = 105 °, FIG. 23A: Ψ = 120 °, FIG. 23B: Ψ = 135 °, FIG. 24 (a): Ψ = 150 °, FIG. 24 (b): Ψ = 165 °, FIG. 25 (a): Ψ = 0 °, FIG. 25 (b): Ψ = 15 °, FIG. 26 (a): Ψ = 30 °, FIG. 26 (b): Ψ = 45 °, FIG. 27 (a): Ψ = 60 °, FIG. 27 (b): Ψ = 75 °, FIG. a): Ψ = 90 °, FIG. 28B: Ψ = 105 °, FIG. 29A: Ψ = 120 °, FIG. 29B: Ψ = 135 °, FIG. 30A: Ψ = 150 °, Figure 30 (b): ψ = 165 °.

  In these drawings, the horizontal axis indicates Φ (°), and the vertical axis indicates Θ (°). In addition, the hatched areas in these drawings indicate the ranges of Φ and Θ that satisfy the extraction conditions (a) and (b).

  FIG. 36 is a schematic diagram showing the meaning of the types of hatching patterns in FIGS. 1 (a) to 30 (b).

  As shown in FIG. 36, the hatched pattern differs depending on the magnitude of the frequency difference Δf. 1A to 30B, the frequency difference Δf is less than 20 MHz (angle range where the extraction conditions (a) and (b) are not satisfied) is not hatched. Further, the angle range in which the extraction conditions (a) and (b) are satisfied is shown with different patterns every time the frequency difference Δf differs by 10 MHz. The Euler angle may be set so that Δf is in the region of 20 MHz or higher, or Δf may be 40 MHz or higher. In order to secure a pass band, Δf may be an area of 60 MHz or more.

  When implementing the resonator 15 according to the present embodiment, Euler angles (Φ, Θ, Ψ) may be selected from the angle range indicated by hatching in FIGS. 1 (a) to 30 (b).

  At this time, when the thickness tp of the LT layer 7 is a predetermined value, a drawing including the predetermined value in a range of ± 0.05λ with reference to the value of the thickness tp according to the drawing may be used. Specifically, when 0.05λ ≦ tp <0.15λ, FIGS. 1A to 6B relating to tp = 0.1λ may be used. When 0.15λ ≦ tp <0.25λ, FIGS. 7A to 12B relating to tp = 0.2λ may be used. When 0.25λ ≦ tp <0.35λ, FIGS. 13A to 18B relating to tp = 0.3λ may be used. When 0.35λ ≦ tp <0.45λ, FIGS. 19A to 24B relating to tp = 0.4λ may be used. When 0.45λ ≦ tp <0.55λ, FIGS. 25A to 30B relating to tp = 0.5λ may be used.

  When Ψ is a predetermined value, a drawing including the predetermined value in a range of ± 7.5 ° with respect to the value of Ψ according to the drawing may be used. Specifically, when 0 ≦ ψ <7.5 ° or 172.5 ° ≦ ψ <180 °, the diagrams related to ψ = 0 ° (FIGS. 1A, 7A, and 13). a), FIG. 19 (a) or FIG. 25 (a)) may be used. When 7.5 ° ≦ ψ <22.5 °, the diagrams related to ψ = 15 ° (FIG. 1B, FIG. 7B, FIG. 13B, FIG. 19B, or FIG. 25). b)) may be used. When 22.5 ° ≦ ψ <37.5 °, the diagrams related to ψ = 30 ° (FIG. 2A, FIG. 8A, FIG. 14A, FIG. 20A, or FIG. a)) may be used. When 37.5 ° ≦ ψ <52.5 °, the diagrams related to ψ = 45 ° (FIG. 2B, FIG. 8B, FIG. 14B, FIG. 20B, or FIG. 26). b)) may be used. When 52.5 ° ≦ ψ <67.5 °, the diagrams related to ψ = 60 ° (FIG. 3A, FIG. 9A, FIG. 15A, FIG. 21A, or FIG. a)) may be used. When 67.5 ° ≦ ψ <82.5 °, the diagrams related to ψ = 75 ° (FIG. 3B, FIG. 9B, FIG. 15B, FIG. 21B, or FIG. 27). b)) may be used. When 82.5 ° ≦ ψ <97.5 °, the diagrams related to ψ = 90 ° (FIG. 4A, FIG. 10A, FIG. 16A, FIG. 22A, or FIG. 28). a)) may be used. When 97.5 ° ≦ ψ <112.5 °, the diagrams related to ψ = 105 ° (FIG. 4B, FIG. 10B, FIG. 16B, FIG. 22B, or FIG. 28). b)) may be used. In addition, when 112.5 ° ≦ ψ <127.5 °, the diagrams related to ψ = 120 ° (FIG. 5A, FIG. 11A, FIG. 17A, FIG. 23A, or FIG. 29 (a)) may be used. When 127.5 ° ≦ ψ <142.5 °, the diagrams related to ψ = 135 ° (FIG. 5B, FIG. 11B, FIG. 17B, FIG. 23B, or FIG. 29). b)) may be used. When 142.5 ° ≦ ψ <157.5 °, the diagrams related to ψ = 150 ° (FIG. 6A, FIG. 12A, FIG. 18A, FIG. 24A, or FIG. 30). a)) may be used. When 157.5 ° ≦ ψ <172.5 °, the diagrams related to ψ = 165 ° (FIG. 6B, FIG. 12B, FIG. 18B, FIG. 24B, or FIG. 30). b)) may be used.

[Electrode thickness]
As described above, the thickness te of the conductive layer 9 (IDT electrode 19 and reflector 21) may be appropriately set according to the specifications required for the resonator 15, the material of the conductive layer 9, and the like. Here, an example of the range of the thickness te when the conductive layer 9 is mainly composed of Al is shown.

  FIG. 37A shows the influence of the thickness te of the conductive layer 9 on the frequency difference Δf. In this figure, the horizontal axis indicates the thickness te as a percentage of the wavelength λ, and the vertical axis indicates the frequency difference Δf (MHz).

  In the figure, a line L1 indicates the relationship between the thickness te obtained by the simulation calculation and the frequency difference Δf. The simulation conditions are the same as those of the 8640 case described above except for the thickness te. The LT layer 7 has a thickness tp of 0.6 μm (0.3λ) and an Euler angle of (90, 90, 110). The thickness tp and Euler angle are those in the case where the resonance characteristics are relatively good in the 8640 case described above.

  As shown in this figure, when the thickness te becomes larger than a certain value, the frequency difference Δf becomes smaller. Therefore, the upper limit value of the thickness te can be defined from the viewpoint of the frequency difference Δf. For example, as indicated by a line L2, 7.5% λ at which the frequency difference Δf is about 40 MHz may be set as the upper limit value of the thickness te. Note that this upper limit value may be regarded as the thickness te when the frequency difference Δf starts to rapidly decrease.

  FIG. 37B is a diagram showing the influence of the thickness te of the conductive layer 9 on the impedance phase. In this figure, the horizontal axis indicates the thickness te (% λ), and the vertical axis indicates the impedance phase (°).

  As described with reference to FIG. 33B, the phase of the impedance is preferably closer to 90 ° between the resonance frequency fr and the antiresonance frequency fa. In the figure, a line L3 indicates the maximum value of the impedance phase between the resonance frequency fr and the antiresonance frequency fa for each value of the thickness te. This line L3 is obtained by simulation calculation.

  The simulation conditions are the same as those of the 8640 case described above except for the thickness te. The LT layer 7 has a thickness tp of 0.6 μm (0.3λ) and an Euler angle of (90, 90, 110). The thickness tp and Euler angle are those in the case where the resonance characteristics are relatively good in the 8640 case described above.

  As shown in this figure, when the thickness te becomes thinner than a certain value, the maximum value of the impedance phase becomes smaller. Therefore, the lower limit value of the thickness te can be defined from the viewpoint of the phase of impedance. For example, as indicated by the line L4, 4% λ at which the maximum value of the impedance phase is about 89.85 ° may be set as the lower limit value of the thickness te. Note that this lower limit value may be regarded as the thickness te when the impedance phase starts to rapidly decrease.

  In summary, when the main component of the IDT electrode 19 is Al, the thickness te may be 4% to 7.5% of the wavelength λ, for example. In this case, loss can be reduced while sufficiently ensuring the frequency difference Δf.

[Thickness of high sound velocity layer]
As described above, the thickness th of the high sound velocity layer 5 may be appropriately set according to the specifications required for the resonator 15, the material of the high sound velocity layer 5, and the like. Here, an example of the range of the thickness th is shown.

  FIG. 38 is a diagram illustrating the influence of the thickness th of the high sound velocity layer 5 on the impedance phase. In this figure, the horizontal axis indicates the thickness th as a ratio to the wavelength λ, and the vertical axis indicates the impedance phase (°). In the figure, the line L5 indicates the maximum value of the phase of the impedance between the resonance frequency fr and the antiresonance frequency fa for each value of the thickness th similarly to the line L3 of FIG. This line L5 is obtained by simulation calculation.

  The simulation conditions are the same as those of the 8640 case described above except for the thickness th. The LT layer 7 has a thickness tp of 0.6 μm (0.3λ) and an Euler angle of (90, 90, 110). The thickness tp and Euler angle are those in the case where the resonance characteristics are relatively good in the 8640 case described above.

  As shown in this figure, when the thickness th becomes thinner than a certain value, the maximum value of the impedance phase becomes smaller. Therefore, the lower limit value of the thickness th can be defined from the viewpoint of the phase of impedance. For example, as indicated by a line L6, 1.25λ where the maximum value of the impedance phase is about 89.75 ° may be set as the lower limit value of the thickness th. Note that this lower limit value may be regarded as the thickness th when the phase of the circumferential impedance starts to rapidly decrease.

As described above, in the present embodiment, the acoustic wave element 1 includes the support substrate 3, the high sound velocity layer 5 made of a material that has a higher sound speed than the material of the support substrate 3, and the high sound velocity. It has a piezoelectric layer (LT layer 7) made of a single crystal of LiTaO ₃ and an excitation electrode (IDT electrode 19), which overlaps the layer 5. The IDT electrode 19 has a plurality of electrode fingers 27 extending in parallel with each other along the upper surface of the LT layer 7. Here, twice the pitch p of the plurality of electrode fingers 27 is λ, the thickness of the LT layer 7 is tp, the Euler angles of the LT layer 7 are (φ, θ, ψ), and φ = Φ + 180 ° × i , Θ = Θ + 180 ° × j, ψ = Ψ + 180 ° × k, and i, j, and k are integers. At this time, the thickness tp is not less than 0.05λ and not more than 0.55λ, the angle ψ is not less than 0 ° and less than 180 °, and the angles Φ and Θ are the thicknesses in FIGS. 1 (a) to 30 (b). It is a value that falls within a hatched area in the drawing corresponding to the values of tp and angle Ψ.

Therefore, a resonance phenomenon can be generated at a relatively high resonance frequency fr. For example, even if the pitch p is 1 μm or more, a resonance frequency fr of 3.8 GHz or more can be realized. From another viewpoint, for example, a resonance phenomenon can be generated using an elastic wave having _a velocity ca specified by a product of the resonance frequency fr and twice the pitch p of 7600 m / s or more.

[Example of use of elastic wave device: duplexer]
FIG. 39 is a circuit diagram schematically showing a configuration of a duplexer 101 as an example of use of the acoustic wave device 1. As can be understood from the reference numerals shown in the upper left of the figure, in this figure, the comb electrode 23 is schematically shown by a bifurcated fork shape, and the reflector 21 is a single line bent at both ends. It is represented by

  The duplexer 101 filters, for example, the transmission signal from the transmission terminal 105 and outputs it to the antenna terminal 103, and filters the reception signal from the antenna terminal 103 and outputs it to the pair of reception terminals 107. A reception filter 111.

  The transmission filter 109 is constituted by, for example, a ladder type filter configured by connecting a plurality of resonators 15 in a ladder type. That is, the transmission filter 109 includes a plurality (or one) of resonators 15 (series resonator 15S) connected in series between the transmission terminal 105 and the antenna terminal 103, and a series line (series arm) thereof. And a plurality of (or even one) resonators 15 (parallel resonators 15P, which are parallel arms in another aspect) that connect the reference potential and the reference potential. Note that the plurality of resonators 15 constituting the transmission filter 109 are provided on the same composite substrate 2, for example.

  The plurality of series resonators 15S basically have the same resonance frequency fr and the same anti-resonance frequency fa. The plurality of parallel resonators 15P basically have the same resonance frequency fr and the same anti-resonance frequency fa. In the series resonator 15S and the parallel resonator 15P, the resonance frequency fr and the anti-resonance frequency fa are set so that the resonance frequency fr of the series resonator 15S and the anti-resonance frequency fa of the parallel resonator 15P substantially coincide with each other. Thus, the transmission filter 109 functions as a filter having a pass band in a slightly narrower range than the frequency range (attenuation region) from the resonance frequency fr of the parallel resonator 15P to the antiresonance frequency fa of the series resonator 15S. The width of the attenuation region is approximately the sum of the frequency difference Δf of the parallel resonator 15P and the frequency difference Δf of the series resonator 15S.

  The reception filter 111 includes, for example, a resonator 15 and a multimode filter (including a double mode filter) 113. The multimode filter 113 includes a plurality of (three in the illustrated example) IDT electrodes 19 arranged in the propagation direction of the elastic wave, and a pair of reflectors 21 disposed on both sides thereof. Note that the resonator 15 and the multimode filter 113 constituting the reception filter 111 are provided, for example, on the same composite substrate 2.

  The transmission filter 109 and the reception filter 111 may be provided on the same composite substrate 2 or may be provided on different composite substrates 2. From another viewpoint, the transmission filter 109 and the reception filter 111 may have the same thickness tp and / or Euler angle of the LT layer 7 or may be different from each other. The Euler angles shown by hatching in FIGS. 1A to 30B may be applied to all the IDT electrodes 19 of the duplexer 101, or may be applied to some IDT electrodes 19. May only be applied.

  FIG. 39 is merely an example of the configuration of the duplexer 101. Therefore, for example, the reception filter 111 may be configured by a ladder filter in the same manner as the transmission filter 109. Further, a capacitor and / or an inductor may be provided at an appropriate position. Further, although the duplexer including the transmission filter 109 and the reception filter 111 has been described as the duplexer 101, the duplexer (multiplexer) may include three or more filters.

[Usage example of elastic wave device: communication device]
FIG. 40 is a block diagram illustrating a main part of a communication device 151 as an example of use of the acoustic wave device 1. The communication device 151 performs wireless communication using radio waves, and includes a duplexer 101.

  In the communication device 151, a transmission information signal TIS including information to be transmitted is modulated and increased in frequency (converted into a high frequency signal having a carrier frequency) by an RF-IC (Radio Frequency Integrated Circuit) 153 to be transmitted signal TS. It is said. Unnecessary components other than the transmission passband are removed from the transmission signal TS by the bandpass filter 155, amplified by the amplifier 157, and input to the duplexer 101 (transmission terminal 105). Then, the duplexer 101 (transmission filter 109) removes unnecessary components other than the transmission passband from the input transmission signal TS, and outputs the transmission signal TS after the removal from the antenna terminal 103 to the antenna 159. . The antenna 159 converts the input electric signal (transmission signal TS) into a radio signal (radio wave) and transmits it.

  In the communication device 151, a radio signal (radio wave) received by the antenna 159 is converted into an electric signal (reception signal RS) by the antenna 159 and input to the duplexer 101 (antenna terminal 103). The duplexer 101 (reception filter 111) removes unnecessary components other than the reception passband from the input reception signal RS and outputs the result from the reception terminal 107 to the amplifier 161. The output received signal RS is amplified by the amplifier 161, and unnecessary components other than the reception passband are removed by the band pass filter 163. Then, the reception signal RS is subjected to frequency reduction and demodulation by the RF-IC 153 to be a reception information signal RIS.

  The transmission information signal TIS and the reception information signal RIS may be low-frequency signals (baseband signals) including appropriate information, and are, for example, analog audio signals or digitized audio signals. The pass band of the radio signal may be set as appropriate, and in the present embodiment, a relatively high frequency pass band (for example, 3.8 GHz or more) is also possible. The modulation method may be any of phase modulation, amplitude modulation, frequency modulation, or a combination of any two or more thereof. As the circuit method, the direct conversion method is illustrated in FIG. 40, but other appropriate methods may be used. For example, a double superheterodyne method may be used. FIG. 40 schematically shows only the main part, and a low-pass filter, an isolator, or the like may be added at an appropriate position, or the position of an amplifier or the like may be changed.

  The technology according to the present disclosure is not limited to the above embodiments, and may be implemented in various aspects.

  As understood from the multimode filter 113 shown in FIG. 39, the acoustic wave element is not limited to a one-port acoustic wave resonator. For example, the acoustic wave element may be of a transversal type. Further, the multimode filter is not limited to a longitudinal coupling type in which IDT electrodes are arranged in the propagation direction of elastic waves, but is a lateral coupling type in which IDT electrodes are arranged in a direction orthogonal to the propagation direction of elastic waves. It may be a thing.

  Further, the Euler angle of the LT layer may be selected from the extraction conditions (a) and (b) that satisfy only (a). That is, the Euler angle at which the product of the resonance frequency and twice the pitch (or the actual elastic wave velocity) is 7600 m / s or more is selected, and the frequency difference Δf may not be a problem. This is because the frequency difference Δf does not become a problem depending on the mode of the acoustic wave element, while the effect of increasing the frequency with respect to the pitch of the electrode fingers can be obtained.

  Further, if the high sound velocity layer can secure a thickness sufficient to support the LT layer, the support substrate can be omitted.

  DESCRIPTION OF SYMBOLS 1 ... Elastic wave element, 3 ... Support substrate, 5 ... High sound velocity layer, 7 ... LT layer (piezoelectric layer), 19 ... IDT electrode (excitation electrode), 27 ... Electrode finger.

Claims (7)

A support substrate;
A high sound velocity layer made of a material that is superimposed on the support substrate and has a speed of sound faster than the material of the support substrate;
A piezoelectric layer overlying the high sound velocity layer and made of a single crystal of LiTaO ₃ ;
An excitation electrode having a plurality of electrode fingers extending in parallel with each other along the upper surface of the piezoelectric layer;
Have
Λ is twice the pitch of the plurality of electrode fingers,
The thickness of the piezoelectric layer is tp,
The Euler angles of the piezoelectric layer are (φ, θ, ψ),
φ = Φ + 180 ° × i,
θ = Θ + 180 ° × j,
ψ = Ψ + 180 ° × k,
When i, j, and k are integers,
An acoustic wave device in which the piezoelectric layer satisfies any one of the following conditions A to E.
A: 0.05λ ≦ tp <0.15λ, and any one of the following conditions a1 to a12 is satisfied.
a1: 0 ≦ ψ <7.5 ° or 172.5 ° ≦ ψ <180 °, and Φ and Θ are in the hatched range in FIG.
a2: 7.5 ° ≦ ψ <22.5 °, and Φ and Θ are in the hatched range in FIG.
a3: 22.5 ° ≦ ψ <37.5 °, and Φ and Θ are in the hatched range in FIG.
a4: 37.5 ° ≦ ψ <52.5 °, and Φ and Θ are in the hatched range in FIG.
a5: 52.5 ° ≦ ψ <67.5 °, and Φ and Θ are in the hatched range in FIG.
a6: 67.5 ° ≦ ψ <82.5 °, and Φ and Θ are in the hatched range in FIG.
a7: 82.5 ° ≦ ψ <97.5 °, and Φ and Θ are in the hatched range in FIG.
a8: 97.5 ° ≦ ψ <112.5 °, and Φ and Θ are in the hatched range in FIG. 4B.
a9: 112.5 ° ≦ ψ <127.5 °, and Φ and Θ are in the hatched range in FIG.
a10: 127.5 ° ≦ ψ <142.5 °, and Φ and Θ are in the hatched range in FIG.
a11: 142.5 ° ≦ ψ <157.5 °, and Φ and Θ are in the hatched range in FIG.
a12: 157.5 ° ≦ ψ <172.5 °, and Φ and Θ are in the hatched range in FIG. 6B.
B: 0.15λ ≦ tp <0.25λ, and any one of the following conditions b1 to b12 is satisfied.
b1: 0 ≦ ψ <7.5 ° or 172.5 ° ≦ ψ <180 °, and Φ and Θ are in the hatched range in FIG.
b2: 7.5 ° ≦ ψ <22.5 °, and Φ and Θ are in the hatched range in FIG. 7B.
b3: 22.5 ° ≦ ψ <37.5 °, and Φ and Θ are in the hatched range in FIG.
b4: 37.5 ° ≦ ψ <52.5 °, and Φ and Θ are in the hatched range in FIG. 8B.
b5: 52.5 ° ≦ ψ <67.5 °, and Φ and Θ are in the hatched range in FIG. 9A.
b6: 67.5 ° ≦ ψ <82.5 °, and Φ and Θ are in the hatched range in FIG. 9B.
b7: 82.5 ° ≦ ψ <97.5 °, and Φ and Θ are in the hatched range in FIG.
b8: 97.5 ° ≦ ψ <112.5 °, and Φ and Θ are in the hatched range in FIG.
b9: 112.5 ° ≦ ψ <127.5 °, and Φ and Θ are in the hatched range in FIG.
b10: 127.5 ° ≦ ψ <142.5 °, and Φ and Θ are in the hatched range in FIG.
b11: 142.5 ° ≦ ψ <157.5 °, and Φ and Θ are in the hatched range in FIG.
b12: 157.5 ° ≦ ψ <172.5 °, and Φ and Θ are in the hatched range in FIG.
C: 0.25λ ≦ tp <0.35λ, and any one of the following conditions c1 to c12 is satisfied.
c1: 0 ≦ ψ <7.5 ° or 172.5 ° ≦ ψ <180 °, and Φ and Θ are in the hatched range in FIG.
c2: 7.5 ° ≦ ψ <22.5 °, and Φ and Θ are in the hatched range in FIG.
c3: 22.5 ° ≦ ψ <37.5 °, and Φ and Θ are in the hatched range in FIG.
c4: 37.5 ° ≦ ψ <52.5 °, and Φ and Θ are in the hatched range in FIG.
c5: 52.5 ° ≦ ψ <67.5 °, and Φ and Θ are in the hatched range in FIG.
c6: 67.5 ° ≦ ψ <82.5 °, and Φ and Θ are in the hatched range in FIG.
c7: 82.5 ° ≦ ψ <97.5 °, and Φ and Θ are in the hatched range in FIG.
c8: 97.5 ° ≦ ψ <112.5 °, and Φ and Θ are in the hatched range in FIG.
c9: 112.5 ° ≦ ψ <127.5 °, and Φ and Θ are in the hatched range in FIG.
c10: 127.5 ° ≦ ψ <142.5 °, and Φ and Θ are in the hatched range in FIG.
c11: 142.5 ° ≦ ψ <157.5 °, and Φ and Θ are in the hatched range in FIG.
c12: 157.5 ° ≦ ψ <172.5 °, and Φ and Θ are in the hatched range in FIG. 18B.
D: 0.35λ ≦ tp <0.45λ, and any one of the following conditions d1 to d12 is satisfied.
d1: 0 ≦ ψ <7.5 ° or 172.5 ° ≦ ψ <180 °, and Φ and Θ are in the hatched range in FIG.
d2: 7.5 ° ≦ ψ <22.5 °, and Φ and Θ are in the hatched range in FIG. 19B.
d3: 22.5 ° ≦ ψ <37.5 °, and Φ and Θ are in the hatched range in FIG.
d4: 37.5 ° ≦ ψ <52.5 °, and Φ and Θ are in the hatched range in FIG.
d5: 52.5 ° ≦ ψ <67.5 °, and Φ and Θ are in the hatched range in FIG.
d6: 67.5 ° ≦ ψ <82.5 °, and Φ and Θ are in the hatched range in FIG.
d7: 82.5 ° ≦ ψ <97.5 °, and Φ and Θ are in the hatched range in FIG.
d8: 97.5 ° ≦ ψ <112.5 °, and Φ and Θ are in the hatched range in FIG.
d9: 112.5 ° ≦ ψ <127.5 °, and Φ and Θ are in the hatched range in FIG.
d10: 127.5 ° ≦ ψ <142.5 °, and Φ and Θ are in the hatched range in FIG.
d11: 142.5 ° ≦ ψ <157.5 °, and Φ and Θ are in the hatched range in FIG.
d12: 157.5 ° ≦ ψ <172.5 °, and Φ and Θ are in the hatched range in FIG.
E: 0.45λ ≦ tp <0.55λ, and any one of the following conditions e1 to e12 is satisfied.
e1: 0 ≦ ψ <7.5 ° or 172.5 ° ≦ ψ <180 °, and Φ and Θ are in the hatched range in FIG.
e2: 7.5 ° ≦ ψ <22.5 °, and Φ and Θ are in the hatched range in FIG.
e3: 22.5 ° ≦ ψ <37.5 °, and Φ and Θ are in the hatched range in FIG.
e4: 37.5 ° ≦ ψ <52.5 °, and Φ and Θ are in the hatched range in FIG.
e5: 52.5 ° ≦ ψ <67.5 °, and Φ and Θ are in the hatched range in FIG.
e6: 67.5 ° ≦ ψ <82.5 °, and Φ and Θ are in the hatched range in FIG.
e7: 82.5 ° ≦ ψ <97.5 °, and Φ and Θ are in the hatched range in FIG.
e8: 97.5 ° ≦ ψ <112.5 °, and Φ and Θ are in the hatched range in FIG.
e9: 112.5 ° ≦ ψ <127.5 °, and Φ and Θ are in the hatched range in FIG.
e10: 127.5 ° ≦ ψ <142.5 °, and Φ and Θ are in the hatched range in FIG.
e11: 142.5 ° ≦ ψ <157.5 °, and Φ and Θ are in the hatched range in FIG.
e12: 157.5 ° ≦ ψ <172.5 °, and Φ and Θ are in the hatched range in FIG. A support substrate;
A high sound velocity layer made of a material that is superimposed on the support substrate and has a speed of sound faster than the material of the support substrate;
A piezoelectric layer overlying the high sound velocity layer and made of a single crystal of LiTaO ₃ ;
An excitation electrode having a plurality of electrode fingers extending in parallel with each other along the upper surface of the piezoelectric layer;
Have
The Euler angle of the piezoelectric layer is an angle at which a velocity of an elastic wave propagating in a direction orthogonal to the plurality of electrode fingers along the upper surface of the piezoelectric layer is 7600 m / s or more. The acoustic wave device according to claim 1, wherein the high sound velocity layer is made of a material having a longitudinal wave sound velocity of 11000 m / s or more. The acoustic wave device according to any one of claims 1 to 3, wherein a thickness of the high sound velocity layer is 1.25λ or more, where λ is twice the pitch of the plurality of electrode fingers. The excitation electrode is mainly composed of Al,
The elastic wave according to any one of claims 1 to 4, wherein a thickness of the excitation electrode is not less than 4% and not more than 7.5% of λ, where λ is twice the pitch of the plurality of electrode fingers. element. An antenna terminal;
A transmission filter that filters a transmission signal and outputs the filtered signal to the antenna terminal;
A reception filter for filtering a reception signal from the antenna terminal,
The said transmission filter or the said reception filter is a duplexer which has an elastic wave element of any one of Claims 1-5. An antenna,
The duplexer according to claim 6, wherein the antenna terminal is connected to the antenna.
An RF-IC electrically connected to the duplexer;
A communication device.

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