Elastic wave apparatus and elastic wave filter

Abstract

To provide an elastic wave device that satisfies the requirement of broad bandwidth. [Solution] The elastic wave device 100 comprises elastic wave resonators 1 and 2, and the elastic wave resonator 1 includes a first piezoelectric layer having Euler angles (ψ1, θ1, φ1) and an IDT electrode 10, where ψ1 is [(85° or more and 95° or less) + 180° × n (n is an integer)], θ1 is [(85° or more and 95° or less) + 180° × n], and φ1 is [(30° or more and 140° or less) + 180° × n], and the first pressure The thickness of the electrolytic layer is less than or equal to the wavelength λ1. The elastic wave resonator 2 includes a second piezoelectric layer having Euler angles (ψ2, θ2, φ2) and an IDT electrode 20, where ψ2 is [(85° or more and 95° or less) + 180° × n], θ2 is [(85° or more and 95° or less) + 180° × n], and φ2 is [(-40° or more and 20° or less) + 180° × n]. The elastic wave resonators 1 and 2 are integrated into a single chip.

Description

[[Technical Field]]

[0001] The present invention relates to an acoustic wave device and an acoustic wave filter. [[Background Art]]

[0002] Patent Document 1 discloses an acoustic wave device that has a rotated Y-cut piezoelectric layer and can excite acoustic waves in SV mode and SH mode. [[Prior Art Literature]] [[Patent Literature]]

[0003] [[Patent Document 1]] Japanese Unexamined Patent Publication No. 2015-73331 [[Summary of Invention]] [[Problem to be Solved by the Invention]]

[0004] Along with the increase in capacity of mobile communication, there is a demand for acoustic wave devices that satisfy the requirement for wider bandwidth.

[0005] Accordingly, the present invention has been made to solve the above problem, and an object of the present invention is to provide an acoustic wave device and an acoustic wave filter that satisfy the requirement for wider bandwidth. [[Means for Solving the Problem]]

[0006] An elastic wave apparatus according to one aspect of the present invention comprises a first elastic wave resonator and a second elastic wave resonator electrically connected to each other, the first elastic wave resonator includes a first piezoelectric layer having Euler angles (ψ1, θ1, φ1) and a first IDT (InterDigital Transducer) electrode disposed in the first piezoelectric layer, where ψ1 is [(85° or more and 95° or less) + 180° × n (n is an integer)], θ1 is [(85° or more and 95° or less) + 180° × n], φ1 is [(30° or more and 140° or less) + 180° × n], the thickness of the first piezoelectric layer is 1 × λ1 or less when the wavelength of the elastic wave determined by the electrode finger period of the first IDT electrode is λ1, and the second elastic wave resonator The device includes a second piezoelectric layer having Euler angles (ψ2, θ2, φ2) and a second IDT electrode disposed in the second piezoelectric layer, where ψ2 is [(85° or greater and 95° or less) + 180° × n], θ2 is [(85° or greater and 95° or less) + 180° × n], and φ2 is [(-40° or greater and 20° or less) + 180° × n], and the first and second elastic wave resonators are integrated into a single chip.

[0007] An elastic wave filter according to one aspect of the present invention comprises a first input / output terminal and a second input / output terminal, one or more series arm resonators arranged in a path connecting the first input / output terminal and the second input / output terminal, and one or more parallel arm resonators connected between the one or more series arm resonators and ground, wherein at least one of the one or more series arm resonators is the first elastic wave resonator described above, and at least one of the one or more parallel arm resonators is the second elastic wave resonator described above. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an elastic wave device and an elastic wave filter that satisfy high frequency and broad bandwidth requirements. [Brief explanation of the drawing]

[0009] [Figure 1] These are a plan view and a cross-sectional view of an elastic wave apparatus according to an embodiment. [Figure 2A]This graph shows the impedance characteristics of the first elastic wave resonator according to the embodiment. [Figure 2B] This is a graph showing the phase characteristics of the first elastic wave resonator according to the embodiment. [Figure 3] This graph shows the impedance characteristics of the second elastic wave resonator according to the embodiment. [Figure 4] This graph shows the impedance characteristics of a second elastic wave resonator according to a modified example 1 of the embodiment. [Figure 5] This is a cross-sectional view of an elastic wave apparatus according to a modified example 2 of the embodiment. [Figure 6] This graph shows the relationship between the third Euler angle φ and the electromechanical coupling coefficient K2 when S0 mode and SH0 mode elastic waves propagate. [Figure 7] This is a circuit diagram of an elastic wave filter according to an embodiment. [Figure 8] This is a plan view showing the electrode layout of an elastic wave filter according to an embodiment. [Modes for carrying out the invention]

[0010] The embodiments of this disclosure will be described in detail below with reference to the drawings. The embodiments described below are all general or specific examples. The numerical values, shapes, materials, components, arrangement of components, and connection configurations shown in the following embodiments are examples only and are not intended to limit the present invention.

[0011] The figures are schematic diagrams that have been appropriately emphasized, omitted, or had their proportions adjusted to illustrate the present invention, and are not necessarily strictly accurate representations. Actual shapes, positional relationships, and proportions may differ. In each figure, substantially identical components are denoted by the same reference numerals, and redundant explanations may be omitted or simplified.

[0012] Furthermore, terms indicating the relationship between elements such as "parallel" and "perpendicular", terms indicating the shape of elements such as "rectangle", and numerical ranges do not express only strict meanings, but are meant to include substantially equivalent ranges, for example, an error of about several percent.

[0013] Furthermore, in the present disclosure, the passband of an acoustic wave device or an acoustic wave filter is defined as the frequency band between two frequencies that are 3 dB larger than the minimum value of insertion loss within the passband.

[0014] Furthermore, in the resonance characteristics of the acoustic wave device of the present disclosure, the resonance frequency and the anti-resonance frequency are derived, for example, by bringing an RF probe into contact with two input / output terminals of the acoustic wave device and measuring reflection characteristics (impedance characteristics) with a network analyzer or the like in a state where the acoustic wave device is not connected to other circuit elements.

[0015] Furthermore, in the present disclosure, the "main component of a material" refers to a component that accounts for more than 50% by weight of the material. The main component may exist in any one of single crystal, polycrystal, and amorphous states, or in a state where these are mixed.

[0016] Furthermore, in the present disclosure, that two acoustic wave resonators are integrated into one chip means that at least one of the following is satisfied: (1) the two acoustic wave resonators are housed in one package, (2) the two acoustic wave resonators are formed on a common support substrate, and (3) the IDT electrodes of the two acoustic wave resonators are formed on a common piezoelectric layer.

[0017] (Embodiment) [Configuration of Acoustic Wave Device 100 According to Embodiment 1] FIG. 1 is a plan view and a cross-sectional view of the acoustic wave device 100 according to the embodiment. FIG. 1(a) is a plan view of the main surface 31a of the piezoelectric layer 31 viewed from the positive z-axis side. FIG. 1(b) is a cross-sectional view taken along line Ib-Ib in FIG. 1(a). As shown in FIG. 1, the acoustic wave device 100 includes an acoustic wave resonator 1 and an acoustic wave resonator 2.

[0018] Elastic wave resonator 1 is an example of a first elastic wave resonator and comprises an IDT electrode 10, a piezoelectric layer 31, a low-sonic-velocity layer 32, a high-sonic-velocity layer 33, a support substrate 34, an insulating layer 41, and a dielectric film 42. Elastic wave resonator 2 is an example of a second elastic wave resonator and comprises an IDT electrode 20, a piezoelectric layer 31, a low-sonic-velocity layer 32, a high-sonic-velocity layer 33, a support substrate 34, an insulating layer 41, and a dielectric film 42. The piezoelectric layer 31, the low-sonic-velocity layer 32, the high-sonic-velocity layer 33, and the support substrate 34 constitute a piezoelectric substrate 30. Elastic wave resonators 1 and 2 share the piezoelectric substrate 30 and are integrated into a single chip. Note that the elastic wave apparatus 100 shown in Figure 1 is intended to illustrate the typical structure of the elastic wave resonators 1 and 2 that constitute the elastic wave apparatus 100, and the number and length of the electrode fingers constituting the IDT electrodes 10 and 20 are not limited to this.

[0019] The piezoelectric layer 31 is a common piezoelectric layer having opposing main surfaces 31a (first main surface) and 31b (second main surface) and Euler angles (ψc, θc, φ). ψc is [(85° or more and 95° or less) + 180° × n], and θc is [(85° or more and 95° or less) + 180° × n]. The piezoelectric layer 31 is made of, for example, lithium niobate (LiNbO3) or a material mainly composed of lithium niobate. In other words, the piezoelectric layer 31 is made of an X-cut LiNbO3 piezoelectric single crystal or piezoelectric ceramic (a lithium niobate single crystal or ceramic cut by a plane normalized to an axis (Z-axis) rotated ψc° (90°) from the X-axis with the Y-axis as the central axis, and in which elastic waves propagate in the XY plane direction).

[0020] The thickness of the piezoelectric layer 31 is 1 × λ1 or less, where λ1 is the wavelength of the elastic wave determined by the electrode finger period of the IDT electrode 10. This makes it possible to efficiently excite the S0 (0th-order S-wave) mode elastic wave in the elastic wave resonator 1. Furthermore, from the viewpoint of ensuring crystallinity and thickness uniformity, the thickness of the piezoelectric layer 31 is preferably 200 nm or more.

[0021] The piezoelectric layer 31 may also be made of, for example, lithium tantalate (LiTaO3) or a material mainly composed of lithium tantalate.

[0022] Furthermore, the Euler angle of the piezoelectric layer 31 can be determined by X-ray diffraction techniques such as XRD.

[0023] The piezoelectric layer 31 may consist of a first piezoelectric layer having Euler angles (ψ1, θ1, φ1) and a second piezoelectric layer having Euler angles (ψ2, θ2, φ2). The elastic wave resonator 1 comprises the first piezoelectric layer, and the elastic wave resonator 2 comprises the second piezoelectric layer, with both the first and second piezoelectric layers arranged on the low-sound velocity layer 32. The IDT electrode 10 is arranged on the first piezoelectric layer, and the IDT electrode 20 is arranged on the second piezoelectric layer. ψ1 is [(85° or more and 95° or less) + 180° × n (n is an integer)], θ1 is [(85° or more and 95° or less) + 180° × n], and φ1 is [(30° or more and 140° or less) + 180° × n]. Furthermore, ψ2 is [(85° or greater and 95° or less) + 180° × n], θ2 is [(85° or greater and 95° or less) + 180° × n], and φ2 is [(-40° or greater and 20° or less) + 180° × n]. The thickness of the first piezoelectric layer is 1 × λ1 or less.

[0024] In the elastic wave apparatus 100 according to this embodiment, the piezoelectric layer 31 is a single common piezoelectric layer where the first piezoelectric layer and the second piezoelectric layer satisfy the relationships ψ1=ψ2 and θ1=θ2.

[0025] The IDT electrode 10 is an example of a first IDT electrode and is positioned on the main surface 31a of the piezoelectric layer 31. As shown in Figure 1(a), the IDT electrode 10 has electrode fingers 11a and 11b and busbar electrodes 12a and 12b.

[0026] Multiple electrode fingers 11a are arranged parallel to each other. Multiple electrode fingers 11b are arranged parallel to each other. Multiple electrode fingers 11a and multiple electrode fingers 11b are arranged parallel to each other so as to intersect each other. Busbar electrode 12a is positioned to connect one end of multiple electrode fingers 11a. Busbar electrode 12a extends in a direction intersecting the extension direction of multiple electrode fingers 11a. Busbar electrode 12b is positioned to connect one end of multiple electrode fingers 11b. Busbar electrode 12b extends in a direction intersecting the extension direction of multiple electrode fingers 11b. Busbar electrode 12a and busbar electrode 12b are positioned opposite each other, with multiple electrode fingers 11a and multiple electrode fingers 11b in between. The other end of multiple electrode fingers 11a faces the busbar electrode 12b, and the other end of multiple electrode fingers 11b faces the busbar electrode 12a. The reflective electrodes are positioned on both sides of the IDT electrode 10, adjacent to it, in a direction perpendicular to the extension direction of the electrode fingers 11a and 11b. However, it is not necessary for reflective electrodes to be positioned on both sides of the IDT electrode 10.

[0027] The IDT electrode 10 is positioned such that the direction perpendicular to the multiple electrode fingers 11a and 11b on the main surface 31a is inclined with respect to the X axis by an angle φ1 [(30° or more and 140° or less) + 180° × n].

[0028] The IDT electrode 20 is an example of a second IDT electrode and is positioned on the main surface 31a of the piezoelectric layer 31. As shown in Figure 1(a), the IDT electrode 20 has electrode fingers 21a and 21b and busbar electrodes 22a and 22b.

[0029] Multiple electrode fingers 21a are arranged parallel to each other. Multiple electrode fingers 21b are arranged parallel to each other. Multiple electrode fingers 21a and multiple electrode fingers 21b are arranged parallel to each other so as to intersect each other. Busbar electrode 22a is positioned to connect one end of multiple electrode fingers 21a. Busbar electrode 22a extends in a direction intersecting the extension direction of multiple electrode fingers 21a. Busbar electrode 22b is positioned to connect one end of multiple electrode fingers 21b. Busbar electrode 22b extends in a direction intersecting the extension direction of multiple electrode fingers 21b. Busbar electrode 22a and busbar electrode 22b are positioned opposite each other, with multiple electrode fingers 21a and multiple electrode fingers 21b in between. The other end of multiple electrode fingers 21a faces the busbar electrode 22b, and the other end of multiple electrode fingers 21b faces the busbar electrode 22a. The reflective electrodes are positioned on both sides of the IDT electrode 20, adjacent to the IDT electrode 20, in a direction perpendicular to the extension direction of the electrode fingers 21a and 21b. However, it is not necessary for reflective electrodes to be positioned on both sides of the IDT electrode 20.

[0030] The IDT electrode 20 is positioned such that the direction perpendicular to the multiple electrode fingers 21a and 21b on the main surface 31a is inclined with respect to the X axis by an angle of φ2 [(-40° or more and 20° or less) + 180° × n].

[0031] IDT electrode 10 and IDT electrode 20 are electrically connected.

[0032] Furthermore, if the thickness of the electrode fingers constituting the IDT electrode 10 is t and the density of the IDT electrode 10 is d, then (t / λ1) × d is 8.94 (g / m³). 3 )That concludes the explanation.According to this, even when using an X-cut piezoelectric layer 31 in the elastic wave resonator 1, leakage of S0 mode elastic waves to the support substrate 34 side can be suppressed.

[0033] The IDT electrodes 10 and 20 have, for example, a laminated structure of multiple metal layers. Preferably, at least one of the multiple metal layers constituting the IDT electrode 10 contains a high-density metal such as platinum (Pt), gold (Au), copper (Cu), and tungsten (W).

[0034] Here, we will describe the electrode parameters of IDT electrodes 10 and 20. While the following description focuses on the electrode parameters of IDT electrode 10, the electrode parameters of IDT electrode 20 are defined similarly.

[0035] The wavelength λ1 of the IDT electrode 10 is a unit of length defined by the repetition period of the electrode finger 11a or 11b. Note that if the distance between adjacent electrode fingers is not constant in the IDT electrode 10, the wavelength λ1 of the IDT electrode 10 is the average wavelength λ1 of the IDT electrode 10. AVE Defined by: The average wavelength λ1 of the IDT electrode 10 AVE The formula is defined as 2 × Di / (Ni-1), where Ni is the total number of electrode fingers 11a and 11b included in the IDT electrode 10, and Di is the distance between the centers of the electrode fingers located at one end and the electrode fingers located at the other end of the IDT electrode 10 in the direction of elastic wave propagation.

[0036] Furthermore, if the IDT electrode 10 includes so-called thinned electrodes, the average wavelength λ1 AVE In calculating the total number of electrode fingers Ni, the number of decimated electrodes is excluded, and the center-to-center distance Di is excluded from the line width L of the decimated electrode and one of the two spaces adjacent to the decimated electrode (space width S). ​​Decimated electrodes include floating decimated electrodes, polarity reversal electrodes, and filled electrodes. A floating decimated electrode is an electrode finger that is not connected to either of the two opposing busbar electrodes and is positioned parallel to the electrode finger that is connected to one of the two busbar electrodes. A polarity reversal electrode is an electrode finger that is connected to the same busbar electrode to which both adjacent electrode fingers are connected and is positioned parallel to both adjacent electrode fingers. A filled electrode is an electrode finger that has an electrode finger width of at least twice the average electrode finger width of the electrode fingers excluding the filled electrode and is positioned parallel to the electrode fingers excluding the filled electrode.

[0037] The wavelength λ2 of the IDT electrode 20 is a unit of length defined by the repetition period of electrode finger 21a or 21b. The wavelength λ2 of the IDT electrode 20 is defined in the same way as the wavelength λ1 of the IDT electrode 10.

[0038] The wavelength λ1 of the IDT electrode 10 and the wavelength λ2 of the IDT electrode 20 can be measured by using a scanning electron microscope (SEM), scanning transmission electron microscope (STEM), or transmission electron microscope (TEM) to view the main surface of the piezoelectric substrate 30 on which the IDT electrode 10 is formed in plan view, and / or by viewing the cross-section perpendicular to the extension direction of the electrode fingers 11a and 11b (electrode fingers 21a and 21b), thereby measuring the line width and space width.

[0039] The support substrate 34 is a common support substrate positioned on the main surface 31b side of the piezoelectric layer 31, and is a substrate that supports the piezoelectric layer 31, the IDT electrodes 10 and 20. The support substrate 34 is made of, for example, a non-oxide material, and can be silicon (Si), silicon carbide (SiC), or a material mainly composed of these materials. Since silicon and silicon carbide have high thermal conductivity, using these materials as the support substrate 34 can improve the heat dissipation of the elastic wave device 100.

[0040] The low-sound-velocity layer 32 is a first common dielectric film disposed between the piezoelectric layer 31 and the support substrate 34, and is a layer in which the speed of sound of the bulk wave propagating is slower than that of the bulk wave propagating through the piezoelectric layer 31. The low-sound-velocity layer 32 can be made of, for example, silicon oxide (e.g., silicon dioxide) or a material mainly composed of silicon oxide.

[0041] Furthermore, as the material for the low-sound velocity layer 32, for example, dielectric materials such as glass, silicon oxide, silicon oxynitride, lithium oxide, tantalum oxide, or compounds of silicon oxide to which fluorine, carbon, or boron have been added, or materials mainly composed of the above materials can also be used.

[0042] The high-speed sound layer 33 is a second common dielectric film positioned between the low-speed sound layer 32 and the support substrate 34, and is a layer in which the speed of sound of the bulk wave propagating is faster than that of the bulk wave propagating through the piezoelectric layer 31. For example, silicon nitride (SiN) or a material mainly composed of silicon nitride can be used for the high-speed sound layer 33.

[0043] Furthermore, as the material for the high-speed layer 33, for example, ceramics such as aluminum nitride (AlN), silicon nitride (SiN), zirconia, cordierite, mullite, steatite, forsterite, spinel, and sialon, dielectrics such as aluminum oxide, silicon oxynitride, DLC (diamond-like carbon), and diamond, or materials mainly composed of the above materials can be used. The spinel mentioned above includes aluminum compounds containing one or more elements selected from Mg, Fe, Zn, Mn, etc., and oxygen. Examples of the spinel mentioned above include MgAl2O4, FeAl2O4, ZnAl2O4, and MnAl2O4.

[0044] The low-sonic-velocity layer 32 and the high-sonic-velocity layer 33 constitute a common dielectric layer and are arranged between the piezoelectric layer 31 and the support substrate 34. The common dielectric layer includes the low-sonic-velocity layer 32 and the high-sonic-velocity layer 33 extending from the piezoelectric layer 31 to the support substrate 34.

[0045] The thickness of the low-sound-velocity layer 32 is, for example, greater than 0.15 × λ1 and less than 0.25 × λ1. Similarly, the thickness of the high-sound-velocity layer 33 is, for example, greater than 0.15 × λ1 and less than 1 × λ1. By setting at least one of the thicknesses of the low-sound-velocity layer 32 and the high-sound-velocity layer 33 within the above thickness ranges, it becomes possible to suppress spurious signals of unwanted modes appearing at frequencies higher than the resonance band in elastic wave resonator 1, and spurious signals of unwanted modes appearing at frequencies lower than the resonance band in elastic wave resonator 2.

[0046] The elastic wave apparatus 100 does not necessarily have to include the low-sound-velocity layer 32 and the high-sound-velocity layer 33. In this case, the support substrate 34 may function as a high-sound-velocity layer in which the sound velocity of the propagating bulk wave is faster than that of the bulk wave propagating through the piezoelectric layer 31. This makes it possible to suppress the leakage of elastic waves propagating through the piezoelectric layer 31 to the support substrate 34 side.

[0047] The low-sonic-velocity layer 32 is composed of a first dielectric film and a third dielectric film. The elastic wave resonator 1 may comprise a support substrate 34, a high-sonic-velocity layer 33, a first dielectric film, a first piezoelectric layer, and an IDT electrode 10, while the elastic wave resonator 2 may comprise a support substrate 34, a high-sonic-velocity layer 33, a third dielectric film, a second piezoelectric layer, and an IDT electrode 20.

[0048] Furthermore, the high-speed layer 33 may be composed of a second dielectric film and a fourth dielectric film, and the elastic wave resonator 1 may comprise a support substrate 34, a second dielectric film, a first dielectric film, a first piezoelectric layer, and an IDT electrode 10, while the elastic wave resonator 2 may comprise a support substrate 34, a fourth dielectric film, a third dielectric film, a second piezoelectric layer, and an IDT electrode 20.

[0049] Furthermore, the support substrate 34 may consist of a first support substrate and a second support substrate, with the elastic wave resonator 1 comprising the first support substrate, a second dielectric film, a first dielectric film, a first piezoelectric layer, and an IDT electrode 10, and the elastic wave resonator 2 comprising the second support substrate, a fourth dielectric film, a third dielectric film, a second piezoelectric layer, and an IDT electrode 20. In this case, the elastic wave resonators 1 and 2 are housed in a common package to form a single chip.

[0050] The insulating layer 41 is positioned to cover the IDT electrodes 10 and 20. The insulating layer 41 is mainly composed of, for example, silicon dioxide (SiO2). This reduces spurious emissions. The dielectric film 42 is positioned to cover the insulating layer 41. The dielectric film 42 is a layer in which the sound velocity of the bulk wave propagating is faster than that of the bulk wave propagating through the piezoelectric layer 31. Note that the insulating layer 41 and the dielectric film 42 do not necessarily have to be included in the elastic wave apparatus 100.

[0051] Table 1 shows the parameters of the elastic wave apparatus 100 according to the embodiment. Note that the parameters shown in Table 1 are examples, and the configuration of the elastic wave apparatus 100 is not limited to the parameters shown in Table 1.

[0052] [Table 1]

[0053] As shown in Table 1, elastic wave resonators 1 and 2 share components except for the IDT electrodes 10 and 20, with only the wavelengths of the IDT electrodes 10 and 20 and the Euler angle φ of the piezoelectric layer 31 being different.

[0054] Figure 2A is a graph showing the impedance characteristics of the elastic wave resonator 1 according to the embodiment. Figure 2B is a graph showing the phase characteristics of the elastic wave resonator 1 according to the embodiment. Figures 2A and 2B show the impedance characteristics and phase characteristics of the elastic wave resonator 1 alone. As shown in Figure 2A, the elastic wave resonator 1 has a resonant frequency fr1 where the impedance is minimum and an anti-resonant frequency fa1 where the impedance is maximum. The impedance ratio of the resonant frequency fr1 and the anti-resonant frequency fa1 is 70 dB or more, and the elastic wave resonator 1 has a high Q factor. The resonant frequency fr1 and the anti-resonant frequency fa1 are caused by the excitation signal of the S0 mode elastic wave. Also, as shown in Figure 2B, the phase of the excitation signal in the resonant band is close to 90°, indicating that the intensity of the excitation signal of the S0 mode elastic wave is high. In contrast, the phase in the frequency band above the resonant band is -60° or less, and unwanted waves of higher-order modes are suppressed.

[0055] Figure 3 is a graph showing the impedance characteristics of the elastic wave resonator 2 according to the embodiment. Figure 3 shows the impedance characteristics of the elastic wave resonator 2 alone. As shown in the figure, the elastic wave resonator 2 has a resonant frequency fr2 where the impedance is minimum and an anti-resonant frequency fa2 where the impedance is maximum. The resonant frequency fr2 and the anti-resonant frequency fa2 are caused by the excitation signal of the elastic wave in the SH0 (0th-order SH wave) mode. The impedance ratio of the resonant frequency fr2 and the anti-resonant frequency fa1 is 70 dB or more, and the elastic wave resonator 2 has a high Q factor.

[0056] In the elastic wave apparatus 100 according to the embodiment, the resonance characteristics of elastic wave resonators 1 and 2 change depending on whether or not the insulating layer 41 is present. Figure 4 is a graph showing the impedance characteristics of elastic wave resonator 2B according to Modification 1 of the embodiment. The elastic wave resonator 2B according to Modification 1 differs from the elastic wave resonator 2 according to the embodiment only in that the insulating layer 41 and dielectric film 42 are not present.

[0057] Comparing the resonance characteristics of elastic wave resonator 2 shown in Figure 3 with those of elastic wave resonator 2B shown in Figure 4, the resonance characteristics of elastic wave resonator 2B show multiple resonance points and multiple anti-resonance points, and multiple spurious signals caused by the resonance of elastic waves other than the SH0 wave are observed. In other words, by arranging the insulating layer 41, spurious signals caused by the resonance of elastic waves other than the main mode elastic wave can be suppressed.

[0058] According to the above configuration of the elastic wave device 100, the elastic wave resonator 1 can utilize the high-speed S0 mode as its main mode, and the elastic wave resonator 2 can utilize the low-speed SH0 mode as its main mode. Furthermore, the elastic wave resonators 1 and 2 are electrically connected and integrated into a single chip using a common X-cut piezoelectric layer 31, a common dielectric film, and a common support substrate. Thus, a compact elastic wave device 100 with a wide resonant bandwidth can be provided.

[0059] [2 Configuration of the elastic wave apparatus 100B according to modified example 2] Figure 5 is a cross-sectional view of the elastic wave apparatus 100A according to a modified example 2 of the embodiment. The plan view of the elastic wave apparatus 100A according to this modified example differs from the plan view of the elastic wave apparatus 100 according to the embodiment shown in Figure 1(a) only in that a gap is provided between the elastic wave resonator 1 and the elastic wave resonator 2, extending between the dielectric film 42 and the upper surface of the low-sonicity layer 32. Figure 5 is also a cross-sectional view along the Ib-Ib line when Figure 1(a) is the plan view of the elastic wave apparatus 100A.

[0060] As shown in Figure 5, the elastic wave device 100A comprises an elastic wave resonator 1A and an elastic wave resonator 2A. Compared to the elastic wave device 100 according to the embodiment, the configuration of the piezoelectric substrates of the elastic wave resonators 1A and 2A in this modified example of the elastic wave device 100A differs. Therefore, in the following description of the elastic wave device 100A according to this modified example, the same configuration as the elastic wave device 100 according to the embodiment will be omitted, and the focus will be on the configuration that differs from the elastic wave device 100.

[0061] Elastic wave resonator 1A is an example of a first elastic wave resonator and comprises an IDT electrode 10, a piezoelectric layer 311, a low-sonic-velocity layer 32, a high-sonic-velocity layer 33, a support substrate 34, an insulating layer 41, and a dielectric film 42. Elastic wave resonator 2A is an example of a second elastic wave resonator and comprises an IDT electrode 20, a piezoelectric layer 312, a low-sonic-velocity layer 32, a high-sonic-velocity layer 33, a support substrate 34, an insulating layer 41, and a dielectric film 42. Elastic wave resonators 1A and 2A share the low-sonic-velocity layer 32, the high-sonic-velocity layer 33, and the support substrate 34, and are integrated into a single chip.

[0062] The piezoelectric layer 311 is an example of a first piezoelectric layer and has opposing main surfaces 311a (third main surface) and 311b (fourth main surface), and has Euler angles (ψ1, θ1, φ1). ψ1 is [(85° or more and 95° or less) + 180° × n (n is an integer)], θ1 is [(85° or more and 95° or less) + 180° × n], and φ1 is [(30° or more and 140° or less) + 180° × n].

[0063] The thickness of the piezoelectric layer 311 is 1 × λ1 or less, where λ1 is the wavelength of the elastic wave determined by the electrode finger period of the IDT electrode 10. This makes it possible to efficiently excite the S0 mode elastic wave in the elastic wave resonator 1A. Furthermore, from the viewpoint of ensuring crystallinity and thickness uniformity, the thickness of the piezoelectric layer 311 is preferably 200 nm or more.

[0064] The IDT electrode 10 is an example of a first IDT electrode and is placed on the main surface 311a of the piezoelectric layer 311.

[0065] The low-sound-velocity layer 32 is an example of the first dielectric film, and is located between the piezoelectric layer 311 and the support substrate 34. This layer has a lower sound velocity for the bulk waves propagating through it than for the bulk waves propagating through the piezoelectric layer 311. The high-sound-velocity layer 33 is an example of the second dielectric film, and is located between the low-sound-velocity layer 32 and the support substrate 34. This layer has a higher sound velocity for the bulk waves propagating through it than for the bulk waves propagating through the piezoelectric layer 311. The low-sound-velocity layer 32 and the high-sound-velocity layer 33 are examples of the first dielectric layer.

[0066] The piezoelectric layer 312 is an example of a second piezoelectric layer and has opposing main surfaces 312a (fifth main surface) and 312b (sixth main surface), and has Euler angles (ψ2, θ2, φ2). ψ2 is [(85° or greater and 95° or less) + 180° × n], θ2 is [(85° or greater and 95° or less) + 180° × n], and φ2 is [(-40° or greater and 20° or less) + 180° × n].

[0067] The piezoelectric layers 311 and 312 are made of, for example, LiNbO3 or a material mainly composed of LiNbO3. Alternatively, the piezoelectric layers 311 and 312 may be made of, for example, LiTaO3 or a material mainly composed of LiTaO3.

[0068] The IDT electrode 20 is an example of a second IDT electrode and is placed on the main surface 312a of the piezoelectric layer 312.

[0069] The low-sound-velocity layer 32 is an example of a third dielectric film, and is located between the piezoelectric layer 312 and the support substrate 34. This layer has a lower sound velocity for the bulk waves propagating through it than for the bulk waves propagating through the piezoelectric layer 312. The high-sound-velocity layer 33 is an example of a fourth dielectric film, and is located between the low-sound-velocity layer 32 and the support substrate 34. This layer has a higher sound velocity for the bulk waves propagating through it than for the bulk waves propagating through the piezoelectric layer 312. The low-sound-velocity layer 32 and the high-sound-velocity layer 33 are examples of a second dielectric layer.

[0070] Support substrate 34 is an example of a first support substrate and is positioned on the main surface 311b side of the piezoelectric layer 311. Support substrate 34 is also an example of a second support substrate and is positioned on the main surface 312b side of the piezoelectric layer 312. In this modified example, support substrate 34 is a common support substrate positioned on the main surface 311b side of the piezoelectric layer 311 and on the main surface 312b side of the piezoelectric layer 312.

[0071] According to the above configuration of the elastic wave device 100A, the elastic wave resonator 1A can utilize the high-speed S0 mode as its main mode, and the elastic wave resonator 2A can utilize the low-speed SH0 mode as its main mode. Furthermore, the elastic wave resonators 1A and 2A are electrically connected and integrated into a single chip by a common low-speed layer 32, high-speed layer 33, and support substrate 34. Thus, a compact elastic wave device 100A with a wide resonant bandwidth can be provided.

[0072] In addition, in the elastic wave apparatus 100A according to this modified example, the first dielectric film on the elastic wave resonator 1A (first elastic wave resonator) and the third dielectric film on the elastic wave resonator 2A (second elastic wave resonator) may be separated. Furthermore, the second dielectric film on the elastic wave resonator 1A (first elastic wave resonator) and the fourth dielectric film on the elastic wave resonator 2A (second elastic wave resonator) may be separated.

[0073] Furthermore, in the elastic wave device 100A according to this modified example, the first support substrate provided by the elastic wave resonator 1A (first elastic wave resonator) and the second support substrate provided by the elastic wave resonator 2A (second elastic wave resonator) may be separated. In this case, the first elastic wave resonator and the second elastic wave resonator are housed in a single package. Even in this case, the elastic wave device 100A is integrated into a single chip, making it possible to provide a compact elastic wave device 100A with a wide resonant bandwidth.

[0074] [3. Optimal Euler angle of the piezoelectric layer] Next, the optimization of the Euler angle of the piezoelectric layer 31 in the elastic wave apparatus 100 according to this embodiment will be described.

[0075] Figure 8 is a graph showing the relationship between the Euler angle φ of the piezoelectric layer 31 and the electromechanical coupling coefficient K2 (hereinafter sometimes simply referred to as K2) when S0 mode elastic waves and SH0 mode elastic waves propagate. From the figure, the Euler angle φ for which the K2 of the S0 mode is greater than the K2 of the SH0 mode is [(30° or more and 140° or less) + 180° × n]. Also, the Euler angle φ for which the K2 of the SH0 mode is greater than the K2 of the S0 mode is [(-40° or more and 20° or less) + 180° × n].

[0076] Therefore, by setting the Euler angle φ1 of elastic wave resonator 1 to [(30° or more and 140° or less) + 180° × n], elastic wave resonator 1 can utilize the S0 mode as its primary mode. Similarly, by setting the Euler angle φ2 of elastic wave resonator 2 to [(-40° or more and 20° or less) + 180° × n], elastic wave resonator 2 can utilize the SH0 mode as its primary mode.

[0077] Furthermore, from Figure 8, the Euler angle φ at which K2 in S0 mode is 4% or more and K2 in SH0 mode is 2% or less is [(50° or more and 70° or less) + 180° × n]. Also, the Euler angle φ at which K2 in SH0 mode is 4% or more and K2 in S0 mode is 2% or less is [(-40° or more and 0° or less) + 180° × n].

[0078] Therefore, by setting the Euler angle φ1 of elastic wave resonator 1 to [(50° or more and 70° or less) + 180° × n], elastic wave resonator 1 can ensure a large signal intensity ratio between the dominant S0 mode and the SH0 mode. Similarly, by setting the Euler angle φ2 of elastic wave resonator 2 to [(-40° or more and 0° or less) + 180° × n], elastic wave resonator 2 can ensure a large signal intensity ratio between the dominant SH0 mode and the S0 mode.

[0079] [4. Configuration of the elastic wave filter] Next, the circuit configuration and electrode arrangement configuration of the elastic wave filter 200 using the elastic wave resonators 1 and 2 according to the embodiment will be described.

[0080] Figure 9 is a circuit diagram of an elastic wave filter 200 according to an embodiment. As shown in the figure, the elastic wave filter 200 includes input and output terminals 201 and 202, series arm resonators 211, 212, 213, 214, 215, 216 and 217, and parallel arm resonators 221, 222, 223 and 224.

[0081] The series arm resonators 211 to 217 are arranged in the series arm path connecting the input / output terminal 201 (first input / output terminal) and the input / output terminal 202 (second input / output terminal). Each of the parallel arm resonators 221 to 224 is connected between the series arm path and ground. Each of the series arm resonators 213 and 214 is a series-connected split resonator. Each of the series arm resonators 216 and 217 is a series-connected split resonator.

[0082] With the above configuration, the elastic wave filter 200 constitutes a ladder-type filter having elastic wave resonators. In this embodiment, the elastic wave filter 200 only needs to include one or more series arm resonators and one or more parallel arm resonators.

[0083] Here, each of the series arm resonators 211 to 217 is an elastic wave resonator 1 according to the embodiment, and each of the parallel arm resonators 221 to 224 is an elastic wave resonator 2 according to the embodiment.

[0084] According to this, in the elastic wave filter 200, each of the series arm resonators 211 to 217 can utilize the high-speed S0 mode as its primary mode, and each of the parallel arm resonators 221 to 224 can utilize the low-speed SH0 mode as its primary mode. Therefore, an elastic wave filter 200 with a wide passband can be provided.

[0085] Figure 10 is a plan view showing the electrode layout of the elastic wave filter 200 according to the embodiment. The elastic wave filter 200 comprises a piezoelectric substrate 30 (only the piezoelectric layer 31 is shown) of the elastic wave device 100 according to the embodiment, IDT electrodes (corresponding to the IDT electrode 10 of the elastic wave device 100) each of the series arm resonators 211 to 217, IDT electrodes (corresponding to the IDT electrode 20 of the elastic wave device 100) each of the parallel arm resonators 221 to 224, an insulating layer 41 (not shown), a dielectric film 42 (not shown), input / output terminals 201 and 202, and a frame 50.

[0086] Each IDT electrode is positioned on the main surface 31a of the common piezoelectric layer 31. The IDT electrodes of each of the series arm resonators 211 to 217 are positioned such that the direction perpendicular to the multiple electrode fingers on the main surface 31a is inclined at an angle of φ1 [(30° or more and 140° or less) + 180° × n] with respect to the X axis. Similarly, the IDT electrodes of each of the parallel arm resonators 221 to 224 are positioned such that the direction perpendicular to the multiple electrode fingers on the main surface 31a is inclined at an angle of φ2 [(-40° or more and 20° or less) + 180° × n] with respect to the X axis.

[0087] With the above configuration of the elastic wave filter 200, each of the series arm resonators 211 to 217 can utilize the high-speed S0 mode as its primary mode, and each of the parallel arm resonators 221 to 224 can utilize the low-speed SH0 mode as its primary mode. Furthermore, the series arm resonators 211 to 217 and the parallel arm resonators 221 to 224 are electrically connected and integrated into a single chip. Therefore, a compact elastic wave filter 200 with a wide passband can be provided.

[0088] Furthermore, in the elastic wave filter 200, it is sufficient that at least one IDT electrode of the series arm resonators 211 to 217 is tilted at an angle of φ1 [(30° or more and 140° or less) + 180° × n] with respect to the X axis, and at least one IDT electrode of the parallel arm resonators 221 to 224 is tilted at an angle of φ2 [(-40° or more and 20° or less) + 180° × n] with respect to the X axis.

[0089] [6 Effects, etc.] As described above, the elastic wave apparatus 100 according to the embodiment comprises elastic wave resonators 1 and 2 that are electrically connected to each other. The elastic wave resonator 1 includes a first piezoelectric layer having Euler angles (ψ1, θ1, φ1) and an IDT electrode 10 disposed in the first piezoelectric layer, where ψ1 is [(85° or more and 95° or less) + 180° × n (n is an integer)], θ1 is [(85° or more and 95° or less) + 180° × n], and φ1 is [(30° or more and 140° or less) + 180° × n]. The thickness of the first piezoelectric layer is 1 × λ1 or less, where λ1 is the wavelength of the elastic wave determined by the electrode finger period of the IDT electrode 10. The elastic wave resonator 2 includes a second piezoelectric layer having Euler angles (ψ2, θ2, φ2) and an IDT electrode 20 disposed in the second piezoelectric layer, where ψ2 is [(85° or greater and 95° or less) + 180° × n], θ2 is [(85° or greater and 95° or less) + 180° × n], and φ2 is [(-40° or greater and 20° or less) + 180° × n]. The elastic wave resonator 1 and the elastic wave resonator 2 are integrated into a single chip.

[0090] According to this, elastic wave resonator 1 can utilize the high-speed S0 mode as its primary mode, and elastic wave resonator 2 can utilize the low-speed SH0 mode as its primary mode. Elastic wave resonators 1 and 2 are electrically connected and integrated into a single chip. Therefore, a compact elastic wave device 100 with a wide resonant bandwidth can be provided.

[0091] For example, in the elastic wave apparatus 100, if the thickness of the electrode fingers constituting the IDT electrode 10 is t and the density of the IDT electrode 10 is d, then (t / λ1) × d is 8.94 (g / m³). 3 That's all.

[0092] According to this, even when an X-cut piezoelectric layer 31 is used in the elastic wave resonator 1, leakage of S0 mode elastic waves to the support substrate 34 side can be suppressed.

[0093] For example, in the elastic wave apparatus 100, the IDT electrode 10 contains platinum (Pt).

[0094] According to this, since the IDT electrode 10 contains a high-density metal, even when using an X-cut piezoelectric layer 31, leakage of S0 mode elastic waves to the support substrate 34 side can be suppressed.

[0095] For example, in the elastic wave apparatus 100, the first piezoelectric layer and the second piezoelectric layer are a single common piezoelectric layer 31 having ψ1=ψ2 and θ1=θ2, the piezoelectric layer 31 has opposing main surfaces 31a and 31b, the IDT electrodes 10 and 20 are arranged on the main surface 31a, and the elastic wave apparatus 100 further includes a common support substrate 34 arranged on the main surface 31b side of the piezoelectric layer 31, and a common dielectric layer arranged between the piezoelectric layer 31 and the support substrate 34.

[0096] According to this, since the elastic wave device 100 is equipped with a piezoelectric layer 31 common to the elastic wave resonators 1 and 2, a common dielectric layer, and a support substrate 34, a compact elastic wave device 100 can be provided.

[0097] For example, in the elastic wave apparatus 100, the common dielectric layer includes a low-sonic-velocity layer 32 and a high-sonic-velocity layer 33 extending from the piezoelectric layer 31 toward the support substrate 34, wherein the bulk wave velocity of the low-sonic-velocity layer 32 is lower than the bulk wave velocity of the piezoelectric layer 31 and the support substrate 34, and the bulk wave velocity of the high-sonic-velocity layer 33 is higher than the bulk wave velocity of the low-sonic-velocity layer 32.

[0098] According to this, it is possible to suppress the leakage of elastic waves propagating through the piezoelectric layer 31 to the support substrate 34 side.

[0099] For example, in the elastic wave apparatus 100, the thickness of the low-sound velocity layer 32 is greater than 0.15 × λ1 and less than 0.25 × λ1, and the thickness of the high-sound velocity layer 33 is greater than 0.15 × λ1 and less than 1 × λ1.

[0100] According to this, it becomes possible to suppress spurious signals of unwanted modes that appear at frequencies higher than the resonance band in elastic wave resonator 1, and spurious signals of unwanted modes that appear at frequencies lower than the resonance band in elastic wave resonator 2.

[0101] For example, the elastic wave devices 100 and 100A further include an insulating layer 41 covering the IDT electrodes 10 and 20.

[0102] According to this method, spurious signals caused by resonances of elastic waves other than the main mode can be suppressed.

[0103] Furthermore, for example, in the elastic wave apparatus 100A according to the modified example 2, the piezoelectric layer 311 has Euler angles (ψ1, θ1, φ1) and has opposing main surfaces 311a and 311b, the IDT electrode 10 is arranged on the main surface 311a, and the elastic wave resonator 1A further comprises a support substrate 34 arranged on the main surface 311b side of the piezoelectric layer 311 and a first dielectric layer arranged between the piezoelectric layer 311 and the support substrate 34.

[0104] According to this, elastic wave resonator 1A can utilize the high-speed sound S0 mode as its primary mode.

[0105] For example, in the elastic wave apparatus 100A, the first dielectric layer includes a low-sonic-velocity layer and a high-sonic-velocity layer extending from the piezoelectric layer 311 toward the support substrate 34, wherein the bulk wave velocity of the low-sonic-velocity layer is lower than the bulk wave velocity of the piezoelectric layer 311 and the support substrate 34, and the bulk wave velocity of the high-sonic-velocity layer is higher than the bulk wave velocity of the low-sonic-velocity layer.

[0106] For example, in the elastic wave apparatus 100A, the piezoelectric layer 312 has Euler angles (ψ2, θ2, φ2) and opposing main surfaces 312a and 312b, the IDT electrode 20 is arranged on the main surface 312a, and the elastic wave resonator 2A further comprises a support substrate 34 arranged on the main surface 312b side of the piezoelectric layer 312 and a second dielectric layer arranged between the piezoelectric layer 312 and the support substrate 34.

[0107] According to this, elastic wave resonator 2A can utilize the low-speed sound SH0 mode as its primary mode.

[0108] For example, in the elastic wave apparatus 100A, the second dielectric layer includes a low-sonic-velocity layer and a high-sonic-velocity layer extending from the piezoelectric layer 312 toward the support substrate 34, wherein the bulk wave velocity of the low-sonic-velocity layer is lower than the bulk wave velocity of the piezoelectric layer 312 and the support substrate 34, and the bulk wave velocity of the high-sonic-velocity layer is higher than the bulk wave velocity of the low-sonic-velocity layer.

[0109] For example, in elastic wave devices 100 and 100A, ψ1 is [(85° or more and 95° or less) + 180° × n], θ1 is [(85° or more and 95° or less) + 180° × n], φ1 is [(50° or more and 70° or less) + 180° × n], ψ2 is [(85° or more and 95° or less) + 180° × n], θ2 is [(85° or more and 95° or less) + 180° × n], and φ2 is [(-40° or more and 0° or less) + 180° × n].

[0110] According to this, by setting the third Euler angle φ1 to [(50° or more and 70° or less) + 180° × n], elastic wave resonator 1 can ensure a large signal intensity ratio between the dominant S0 mode and the SH0 mode. Also, by setting the third Euler angle φ2 to [(-40° or more and 0° or less) + 180° × n], elastic wave resonator 2 can ensure a large signal intensity ratio between the dominant SH0 mode and the S0 mode.

[0111] For example, in the elastic wave apparatus 100 (100A), elastic wave resonator 1 (1A) uses the S0 mode as its primary mode, and elastic wave resonator 2 (2A) uses the SH0 mode as its primary mode.

[0112] According to this, a compact elastic wave device 100 (100A) having a wide resonant bandwidth can be provided.

[0113] For example, the elastic wave filter 200 according to the embodiment includes input / output terminals 201 and 202, series arm resonators 211 to 217 arranged in a series arm path connecting the input / output terminals 201 and 202, and parallel arm resonators 221 to 224 connected between the series arm path and ground, wherein at least one of the series arm resonators 211 to 217 is an elastic wave resonator 1 (1A), and at least one of the parallel arm resonators 221 to 224 is an elastic wave resonator 2 (2A), and each of the series arm resonators 211 to 217 and the parallel arm resonators 221 to 224 includes a common piezoelectric layer 31.

[0114] According to this design, each of the series arm resonators 211-217 can utilize the high-speed S0 mode as its primary mode, while each of the parallel arm resonators 221-224 can utilize the low-speed SH0 mode as its primary mode. Furthermore, the series arm resonators 211-217 and the parallel arm resonators 221-224 are electrically connected and integrated into a single chip. Thus, a compact elastic wave filter 200 with a wide passband can be provided.

[0115] (Other embodiments) Although embodiments and modifications of the elastic wave apparatus and elastic wave filter according to the present invention have been described above, the present invention is not limited to the above embodiments and modifications. The present invention also includes other embodiments realized by combining any of the components in the above embodiments and modifications, and modifications obtained by applying various modifications to the above embodiments and modifications that a person skilled in the art can conceive of without departing from the spirit of the present invention. [Industrial applicability]

[0116] The present invention can be widely used in communication devices such as mobile phones as an elastic wave device and elastic wave filter positioned in the front end. [Explanation of symbols]

[0117] 1, 1A, 2, 2A, 2B Elastic wave resonators 10, 20 IDT electrodes 11a, 11b, 21a, 21b electrode fingers 12a, 12b, 22a, 22b busbar electrodes 30, 30A Piezoelectric Substrate 31, 311, 312 Piezoelectric layer 31a, 31b, 311a, 311b, 312a, 312b main surface 32 Low sound speed layer 33 High-sonic layer 34 Support substrate 41 Insulating layer 42 Dielectric film 50 frame 100, 100A elastic wave apparatus 200 Elastic wave filters 201, 202 input / output terminals 211, 212, 213, 214, 215, 216, 217 Series Arm Resonators 221, 222, 223, 224 Parallel Arm Resonators

Claims

1. It comprises a first elastic wave resonator and a second elastic wave resonator that are electrically connected to each other, The first elastic wave resonator is, A first piezoelectric layer having Euler angles (ψ1, θ1, φ1), The first piezoelectric layer includes a first IDT (InterDigital Transducer) electrode, ψ1 is [(85° or greater and 95° or less) + 180° × n (n is an integer)], θ1 is [(85° or greater and 95° or less) + 180° × n], and φ1 is [(30° or greater and 140° or less) + 180° × n], The thickness of the first piezoelectric layer is 1 × λ1 or less, where λ1 is the wavelength of the elastic wave determined by the electrode finger period of the first IDT electrode. The second elastic wave resonator is, A second piezoelectric layer having Euler angles (ψ², θ², φ²), The second IDT electrode is disposed in the second piezoelectric layer, ψ² is [(85° or greater and 95° or less) + 180° × n], θ² is [(85° or greater and 95° or less) + 180° × n], and φ² is [(-40° or greater and 20° or less) + 180° × n], The first elastic wave resonator and the second elastic wave resonator are integrated into a single chip. Elastic wave device.

2. If the thickness of the electrode finger constituting the first IDT electrode is t and the density of the first IDT electrode is d, then (t / λ1) × d is 8.94 (g / m³). ３ ) That's all, The elastic wave apparatus according to claim 1.

3. The first IDT electrode contains platinum (Pt), The elastic wave apparatus according to claim 2.

4. The first piezoelectric layer and the second piezoelectric layer are a single common piezoelectric layer where ψ1 = ψ2 and θ1 = θ2. The common piezoelectric layer has a first main surface and a second main surface that face each other. The first IDT electrode and the second IDT electrode are arranged on the first main surface, The elastic wave apparatus further, A common support substrate disposed on the second main surface side of the common piezoelectric layer, A common dielectric layer is disposed between the common piezoelectric layer and the common support substrate. The elastic wave apparatus according to any one of claims 1 to 3.

5. The common dielectric layer includes a first common dielectric film and a second common dielectric film extending from the common piezoelectric layer toward the common support substrate. The bulk wave sound velocity of the first common dielectric film is lower than the bulk wave sound velocity of the common piezoelectric layer and the common support substrate. The bulk wave sound velocity of the second common dielectric film is higher than the bulk wave sound velocity of the first common dielectric film. The elastic wave apparatus according to claim 4.

6. The thickness of the first common dielectric film is greater than 0.15 × λ1 and less than 0.25 × λ1. The thickness of the second common dielectric film is greater than 0.15 × λ1 and less than 1 × λ1. The elastic wave apparatus according to claim 5.

7. Furthermore, it includes an insulating layer covering the first IDT electrode and the second IDT electrode, The elastic wave apparatus according to any one of claims 1 to 6.

8. The first piezoelectric layer has a third main surface and a fourth main surface that are opposite to each other, The first IDT electrode is positioned on the third main surface, The first elastic wave resonator further, A first support substrate disposed on the fourth main surface side of the first piezoelectric layer, The first dielectric layer is disposed between the first piezoelectric layer and the first support substrate, The elastic wave apparatus according to any one of claims 1 to 3.

9. The first dielectric layer includes a first dielectric film and a second dielectric film extending from the first piezoelectric layer toward the first support substrate. The bulk wave sound velocity of the first dielectric film is lower than the bulk wave sound velocity of the first piezoelectric layer and the first support substrate. The bulk wave sound velocity of the second dielectric film is higher than the bulk wave sound velocity of the first dielectric film. The elastic wave apparatus according to claim 8.

10. The second piezoelectric layer has a fifth main surface and a sixth main surface that are opposite to each other. The second IDT electrode is positioned on the fifth main surface, The second elastic wave resonator further, A second support substrate is disposed on the sixth main surface side of the second piezoelectric layer, The invention comprises a second dielectric layer disposed between the second piezoelectric layer and the second support substrate, The elastic wave apparatus according to any one of claims 1 to 3, 8, and 9.

11. The second dielectric layer includes a third dielectric film and a fourth dielectric film extending from the second piezoelectric layer toward the second support substrate. The bulk wave sound velocity of the third dielectric film is lower than the bulk wave sound velocity of the second piezoelectric layer and the second support substrate. The bulk wave sound velocity of the fourth dielectric film is higher than that of the third dielectric film. The elastic wave apparatus according to claim 10.

12. ψ1 is [(85° or greater and 95° or less) + 180° × n], θ1 is [(85° or greater and 95° or less) + 180° × n], and φ1 is [(50° or greater and 70° or less) + 180° × n], ψ² is [(85° or greater and 95° or less) + 180° × n], θ² is [(85° or greater and 95° or less) + 180° × n], and φ² is [(-40° or greater and 0° or less) + 180° × n]. The elastic wave apparatus according to any one of claims 1 to 11.

13. The first elastic wave resonator utilizes the S0 mode as its primary mode. The second elastic wave resonator utilizes the SH0 mode as its primary mode. The elastic wave apparatus according to any one of claims 1 to 12.

14. First input / output terminal and second input / output terminal, One or more series-arm resonators arranged in the path connecting the first input / output terminal and the second input / output terminal, The system comprises one or more series arm resonators and one or more parallel arm resonators connected between them and ground, At least one of the one or more series-arm resonators is a first elastic wave resonator according to any one of claims 4 to 6. At least one of the one or more parallel arm resonators is a second elastic wave resonator according to any one of claims 4 to 6. Elastic wave filter.

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