Resonator, surface acoustic wave filter and radio frequency front-end module

Abstract

The invention discloses a resonator, a surface acoustic wave filter and a radio frequency front-end module. A dielectric film layer of the resonator is arranged on a substrate, and a piezoelectric film layer is arranged on the dielectric film layer; the metal electrode layer is arranged on the piezoelectric film layer; the surface acoustic wave is restrained in the surface range of the piezoelectric film layer through the dielectric film layer, the bulk wave is transmitted in at least one of the substrate, the dielectric film layer and the piezoelectric film layer, and the influence of a high-frequency miscellaneous mode on the performance of the device can be reduced while the heat dissipation of the device is improved by selecting the proper dielectric film layer and substrate.

Description

Technical Field

[0001] The present application relates to the technical field of surface acoustic wave devices, and in particular to a resonator, a surface acoustic wave filter and a radio frequency front-end module. Background Art

[0002] With the rapid development of communication technology, the frequency is getting higher and higher, and the requirements for filter performance are getting higher and higher. The resonator is a part of the filter, which can amplify or attenuate signals of a specific frequency to achieve the function of a filter. The surface acoustic wave filter uses the piezoelectric properties of piezoelectric materials and uses input and output transducers to convert the input signal of the radio wave into mechanical energy. After processing, the mechanical energy is converted into an electrical signal to filter unnecessary noise signals and improve the quality of the received signal. The surface acoustic wave resonator can improve some of the performance of the surface acoustic wave resonator by setting a functional layer and a substrate under the piezoelectric film layer, such as increasing the resonant frequency of the resonator and increasing the Q value, but the introduction of functional layers, substrates, etc. may be accompanied by the deterioration of other performances, such as high-frequency noise. Summary of the invention

[0003] Based on this, the present application provides a resonator, a surface acoustic wave filter and a radio frequency front-end module, which can suppress the high-frequency heterodyne modes generated when the resonator is working.

[0004] In a first aspect, the present application provides a resonator, the resonator comprising:

[0005] substrate;

[0006] A dielectric thin film layer is disposed on the substrate;

[0007] A piezoelectric film layer is disposed on the dielectric film layer;

[0008] A metal electrode layer, disposed on the piezoelectric film layer;

[0009] Among them, the sound waves when the resonator is working include surface acoustic waves and body waves, the dielectric film layer constrains the surface acoustic waves within the surface range of the piezoelectric film layer, the body waves propagate in the substrate, the dielectric film layer and the piezoelectric film layer, the speed V2 of the body waves propagating in the dielectric film layer is greater than the speed of the body waves propagating in the piezoelectric film layer or greater than the speed of the surface acoustic waves propagating in the piezoelectric film layer, and the speed of the body waves propagating in the substrate is less than or equal to 1.5V2.

[0010] In a second aspect, the present application provides a resonator, the resonator comprising:

[0011] substrate;

[0012] A quartz thin film layer is disposed on the substrate;

[0013] A piezoelectric film layer is disposed on the quartz film layer;

[0014] A metal electrode layer, disposed on the piezoelectric film layer;

[0015] The acoustic waves of the resonator when working include surface acoustic waves and bulk waves, the quartz film layer constrains the surface acoustic waves within the surface range of the piezoelectric film layer, the bulk waves propagate in at least one of the substrate, the quartz film layer and the piezoelectric film layer, and the thickness H of the piezoelectric film layer and / or the quartz film layer satisfies the following relationship:

[0016]

[0017] Among them, α is the ratio of phase shift to π, f r represents the resonant frequency of the surface acoustic wave, if H represents the thickness of the piezoelectric film layer, then θ represents the angle between the propagation direction of the body wave in the piezoelectric film layer and the surface of the piezoelectric film layer, V B (θ) represents the propagation speed of the bulk wave in the piezoelectric thin film layer. If H represents the thickness of the quartz thin film layer, then θ represents the angle between the propagation direction of the bulk wave in the quartz thin film layer and the surface of the quartz thin film layer, V B (θ) represents the propagation speed of the body wave in the quartz thin film layer, and η is a constant greater than 1.

[0018] In a third aspect, the present application provides a resonator, the resonator comprising:

[0019] Silicon substrate;

[0020] A quartz thin film layer is disposed on the silicon substrate;

[0021] A piezoelectric film layer is disposed on the quartz film layer;

[0022] A metal electrode layer, disposed on the piezoelectric film layer;

[0023] The acoustic waves of the resonator when working include surface acoustic waves and bulk waves. The quartz film layer constrains the surface acoustic waves within the surface range of the piezoelectric film layer. The bulk waves propagate in at least one of the silicon substrate, the quartz film layer and the piezoelectric film layer. The propagation direction of the surface acoustic waves is parallel to the direction of the silicon substrate. <110> The directions within a first preset angle offset range of the crystal orientation family are parallel.

[0024] In a fourth aspect, the present application provides a resonator, the resonator comprising:

[0025] substrate;

[0026] A dielectric thin film layer is disposed on the substrate;

[0027] A piezoelectric film layer is disposed on the dielectric film layer;

[0028] A metal electrode layer, disposed on the piezoelectric film layer;

[0029] Among them, the sound waves of the resonator when working include surface acoustic waves and body waves, the dielectric film layer constrains the surface acoustic waves within the surface range of the piezoelectric film layer, and the body waves propagate in at least one of the substrate, the dielectric film layer and the piezoelectric film layer. The material used for the substrate can cause the body waves with a target frequency to leak in the substrate, and the target frequency is greater than the resonant frequency of the surface acoustic wave.

[0030] In a fifth aspect, the present application provides a surface acoustic wave filter, wherein the surface acoustic wave filter comprises a resonator as described in any one of the first to fourth aspects above.

[0031] In a sixth aspect, the present application provides a radio frequency front-end module, which includes the filter as described above.

[0032] The resonator of the embodiment of the present application includes a substrate, a dielectric film layer, a piezoelectric film layer and a metal electrode layer, wherein the dielectric film layer is arranged on the substrate, and the piezoelectric film layer is arranged on the dielectric film layer; the metal electrode layer is arranged on the piezoelectric film layer; the dielectric film layer constrains the surface acoustic wave of the resonator when it is working within the surface range of the piezoelectric film layer; the body wave of the resonator when it is working propagates in at least one of the substrate, the dielectric film layer and the piezoelectric film layer; the embodiment of the present application selects a suitable material to make the speed V2 of the body wave propagating in the dielectric film layer greater than the speed of the body wave propagating in the piezoelectric film layer or greater than the speed of the surface acoustic wave propagating in the piezoelectric film layer, so that the speed of the body wave propagating in the substrate is less than or equal to 1.5V2; or, by controlling the thickness of the piezoelectric film layer and / or the dielectric film layer to satisfy a certain relationship; or, by using a silicon substrate and a quartz film layer to make the propagation direction of the surface acoustic wave and the silicon substrate <110> The direction within the first preset angle offset range of the crystal orientation family is parallel; or, the material used for the substrate can cause the body wave with the target frequency to leak in the substrate; in this way, the influence of the high-frequency stray mode generated by the waveguide mode on the resonator performance can be reduced without affecting the main mode of the resonator operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 is a schematic structural diagram of an embodiment of a resonator of the present application;

[0035] Figure 2 is a structural schematic diagram of another embodiment of the resonator of the present application;

[0036] Figure 3 1 is a schematic diagram of a typical structure of a resonator according to an embodiment of the present application (left) and a schematic diagram of a control scheme of a related art (right);

[0037] Figure 4 This is a temperature distribution diagram of the core chip of a duplexer using a quartz substrate in the related art when the power is loaded at 30 dBm (1 W);

[0038] Figure 5 Yes Figure 4 The temperature distribution diagram of the core chip loaded at the same power after the substrate of the corresponding duplexer is replaced with a quartz film layer / silicon substrate;

[0039] Figure 6 yes Figure 3 Schematic diagram of the admittance simulation comparison between the quartz substrate solution and the quartz film / silicon substrate solution;

[0040] Figure 7 Schematic diagram of waveguide mode propagating in a single-layer film and schematic diagram of waveguide mode propagating in a multi-layer film;

[0041] Figure 8 is a schematic diagram of the waveguide mode leaking from the substrate;

[0042] Figure 9a It is a schematic diagram of the relationship between the waveguide mode position and the film thickness;

[0043] Figure 9b It is a schematic diagram of the relationship between the waveguide mode Q value and the film thickness;

[0044] Fig.10a It is a schematic diagram of the relationship between the starting frequency of body wave radiation and the body wave sound speed;

[0045] Fig.10b Schematic diagram of the relationship between the waveguide mode Q value and the body wave speed;

[0046] Fig.11a This is a schematic diagram of the relationship between the in-plane angle of Si(100) and the body wave speed;

[0047] Fig.11b This is a schematic diagram of the relationship between the Si(110) in-plane angle and the body wave speed;

[0048] Fig.11c This is a schematic diagram of the relationship between the Si(111) in-plane angle and the body wave speed;

[0049] Fig.12 It is the harmonic admittance diagram of surface acoustic wave when the single crystal silicon substrate adopts different cut types;

[0050] Fig.13 It is the backscattered body wave radiation model and the stimulated body wave radiation model;

[0051] Fig.14 is a schematic diagram of the resonance of the waveguide mode;

[0052] Fig.15 is the effect of film thickness on the waveguide mode frequency;

[0053] Fig.16 These are typical dispersion curves and slowness curves. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0055] The flowcharts shown in the accompanying drawings are only examples and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may also be decomposed, combined or partially merged, so the actual execution order may change according to actual conditions.

[0056] It should be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0057] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0058] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0059] The surface acoustic wave resonator can improve some of its performance by setting a functional layer, substrate, etc. under the piezoelectric film layer, such as increasing the resonant frequency of the resonator, increasing the Q value, etc., but the introduction of the functional layer, substrate, etc. may be accompanied by the deterioration of other performances, such as high-frequency stray modes. High-frequency stray modes can be formed in a variety of ways, among which high-frequency stray modes generated by waveguide modes are more common. For example: the resonator of the related art uses a silicon substrate, and a quartz film layer and a piezoelectric film layer are made on the silicon substrate; this scheme enables the resonator to have advantages such as a high Q value; in this resonator structure, when the resonator is working, the metal electrode will not only stimulate the generation of surface acoustic waves, but also stimulate the generation of body waves. At the same time, the surface acoustic wave can also radiate body waves. When the body wave radiates in the depth direction and reflects back and forth in the layers above the substrate, the position where the body wave of certain frequencies reaches after reflection matches the phase of the newly excited body wave at that position, thereby forming a waveguide mode. However, the waveguide mode is usually not required in engineering applications, so it will affect engineering applications and the performance of the resonator.

[0060] In order to solve the above problems, the resonator of the embodiment of the present application includes a substrate, a dielectric film layer, a piezoelectric film layer and a metal electrode layer, the dielectric film layer is arranged on the substrate, the piezoelectric film layer is arranged on the dielectric film layer; the metal electrode layer is arranged on the piezoelectric film layer; the dielectric film layer constrains the surface acoustic wave of the resonator when it is working within the surface range of the piezoelectric film layer; the body wave of the resonator when it is working propagates in at least one of the substrate, the dielectric film layer and the piezoelectric film layer; the embodiment of the present application selects suitable materials for the piezoelectric film layer, the dielectric film layer and the substrate, so that the speed V2 of the body wave propagating in the dielectric film layer is greater than the speed of the body wave propagating in the piezoelectric film layer, or the speed V2 of the body wave propagating in the dielectric film layer is greater than the speed of the surface acoustic wave propagating in the piezoelectric film layer, so that the speed of the body wave propagating in the substrate is less than or equal to 1.5V2; or, by controlling the thickness of the piezoelectric film layer and / or the dielectric film layer to satisfy a certain relationship; or, by using a silicon substrate and a quartz film layer so that the propagation direction of the surface acoustic wave is consistent with the silicon substrate <110> The direction within the first preset angle offset range of the crystal orientation family is parallel; or, the material used for the substrate is capable of causing body waves of a specific target frequency to leak in the substrate; in this way, the influence of high-frequency stray modes generated by the waveguide mode on the performance of the resonator can be reduced without affecting the main mode of operation of the resonator.

[0061] See also Figure 1 , Figure 1 It is a structural schematic diagram of an embodiment of a resonator of the present application.

[0062] A resonator may refer to an electronic component that generates a resonant frequency, and the resonator includes: a substrate, a dielectric film layer, a piezoelectric film layer, and a metal electrode layer. The dielectric film layer is disposed on the substrate; the piezoelectric film layer is disposed on the dielectric film layer; the metal electrode layer is disposed on the piezoelectric film layer, and the metal electrode layer is provided with a metal electrode.

[0063] Among them, the sound waves when the resonator is working include surface acoustic waves and body waves. The dielectric film layer constrains the surface acoustic waves within the surface range of the piezoelectric film layer, and the body waves propagate in the substrate, the dielectric film layer and the piezoelectric film layer. The speed V2 of the body wave propagating in the dielectric film layer is greater than the speed of the body wave propagating in the piezoelectric film layer or greater than the speed of the surface acoustic wave propagating in the piezoelectric film layer, and the speed of the body wave propagating in the substrate is less than or equal to 1.5V2.

[0064] The main working principle of the resonator in the embodiment of the present application is to utilize the piezoelectric properties of the piezoelectric film layer and use the input and output transducers to convert the input signal of the radio wave into mechanical energy (i.e., sound waves). After processing, the mechanical energy (i.e., sound waves) is converted into electrical signals to achieve the goal of filtering out unnecessary signals and noise signals and improving the quality of the received signal. It is widely used in various wireless communication systems, televisions, video recorders and global satellite positioning system receivers. Its main function is to filter out noise signals, and it is simpler to install and smaller in size than traditional LC filters.

[0065] The function of the piezoelectric film layer is to generate a voltage between the two end surfaces when subjected to pressure. The function of the dielectric film layer is to confine the surface acoustic wave within the surface range of the piezoelectric film layer, which can be achieved by selecting the material and thickness of the dielectric film layer. The substrate can improve some performances of the resonator, such as increasing the resonant frequency of the resonator, increasing the Q value, etc. The material of the substrate includes but is not limited to: silicon, gallium arsenide, etc. The material of the piezoelectric film layer includes but is not limited to LiTaO3, LiNbO3, etc. The material of the dielectric film layer includes but is not limited to quartz, etc. The material of the substrate and the material of the dielectric film can be single crystal, polycrystalline or glassy; the piezoelectric film material is single crystal.

[0066] The metal electrodes of the metal electrode layer are arranged in a certain spatial period within a certain range on the surface, and the spatial period is p. The proportion of metal coverage within a spatial period is defined as the metallization ratio (Duty Factor, abbreviated as DF). Adjacent metal electrodes are usually connected to signals with a phase difference of 180 degrees. In this case, the metal electrodes have a special name: Interdigital Transducer (IDT). At this time, the metal electrodes can excite various types of sound waves, and λ is defined as 2p.

[0067] like Figure 2As shown, an IDT is arranged on the piezoelectric film layer. The IDT includes two bus bars and electrode fingers connected to the bus bars. p is the spatial period of the IDT, that is, the distance between the center lines of two adjacent electrode fingers, and λ=2p is defined.

[0068] Acoustic waves are the propagation form of sound, and the object that emits sound is called the sound source; acoustic waves are a type of mechanical wave generated by the vibration of the sound source. Surface acoustic waves (SAW) are elastic waves that propagate along the surface of an elastic material, and whose amplitude decays exponentially with the depth into the surface; in the embodiment of the present application, the role of the dielectric film layer is to confine the surface acoustic wave to the surface range of the piezoelectric film layer. Body waves may refer to waves that propagate in an infinite medium; in the embodiment of the present application, body waves propagate in the substrate, dielectric film layer, and piezoelectric film layer.

[0069] When the resonator is working, the metal electrode will not only stimulate the generation of surface acoustic waves, but also stimulate the generation of body waves. At the same time, the surface acoustic waves can also radiate body waves. When the body waves radiate in the depth direction (i.e., toward the substrate) and reflect back and forth in the layers above the substrate, the position where the body waves of certain frequencies arrive after reflection matches the phase of the newly excited body waves at that position, thus forming a waveguide mode. However, the waveguide mode is usually not required in engineering applications, so the waveguide mode will affect engineering applications and the performance of the resonator.

[0070] When sound waves propagate in different media, the different propagation speeds cause reflection and refraction of sound. When a sound wave encounters a medium interface during its travel, the phenomenon that part or all of its energy returns to the original medium is called reflection, and the reflection in which all energy is returned is called total reflection. At the interface, part of the sound wave energy enters the second medium, and the direction of the wave vector of the sound wave entering the second medium usually deviates from the wave vector of the incident wave. This phenomenon is called refraction.

[0071] When the velocity V2 of body waves propagating in the dielectric film layer is greater than the velocity of body waves propagating in the piezoelectric film layer or greater than the velocity of surface acoustic waves propagating in the piezoelectric film layer, surface acoustic waves or body waves of specific frequencies will be confined in the piezoelectric film layer and the dielectric film layer due to the total reflection effect. Specifically, surface acoustic waves or body waves with frequencies less than the resonant frequency of the surface acoustic waves in a smaller frequency band are easily confined in the piezoelectric film layer and the dielectric film layer, such as surface acoustic waves or body waves with frequencies less than 1.1 times the resonant frequency of the surface acoustic waves, thereby achieving a high Q value of the main mode of the surface acoustic waves.

[0072] It can be understood that when the velocity V2 of the body wave propagating in the dielectric film layer is greater than the velocity of the body wave propagating in the piezoelectric film layer or greater than the velocity of the surface acoustic wave propagating in the piezoelectric film layer, the surface acoustic wave or body wave of a specific frequency will be confined in the piezoelectric film layer and the dielectric film layer due to the total reflection effect, but the body wave with a frequency greater than the specific frequency will leak from the dielectric film layer to the substrate, and the higher the frequency of this part of the body wave, the easier it is to leak from the substrate. The embodiment of the present application defines that the starting frequency of the body wave leaking from the substrate can be understood as the minimum frequency of the body wave that can leak from the substrate.

[0073] When the velocity of the bulk wave propagating in the substrate is less than or equal to 1.5V2, the starting frequency of the bulk wave leaking from the substrate can be reduced. When the bulk wave is refracted at the interface between the substrate and the dielectric thin film layer (i.e., leaking from the substrate), the energy of the bulk wave reflected at the interface will be reduced. If the frequency of the formed waveguide mode is greater than the starting frequency of the bulk wave leakage, the Q value of the waveguide mode will be reduced due to the reduction of the bulk wave energy, thereby weakening the intensity of the waveguide mode.

[0074] Therefore, the embodiments of the present application can select suitable materials for the substrate, the dielectric film layer, and the piezoelectric film layer, so that the speed V2 of the propagation of the body wave in the dielectric film layer is greater than the speed of the propagation of the body wave in the piezoelectric film layer or greater than the speed of the propagation of the surface acoustic wave in the piezoelectric film layer, and the speed of the propagation of the body wave in the substrate is less than or equal to 1.5V2. This can reduce the intensity of the waveguide mode while having little impact on the main operating mode of the surface acoustic wave resonator, thereby reducing the impact of the high-frequency stray mode caused by the waveguide mode on the resonator performance.

[0075] For example, the sound velocity of slow shear waves in LiTaO3 in rotating Y-cut X-propagation is about 3300-3800 m / s, the sound velocity of slow shear waves in LiNbO3 in rotating Y-cut X-propagation is about 3400-4100, the sound velocity of slow shear waves in quartz in rotating Y-cut X-propagation is about 3300-5000 m / s, and the sound velocity of slow shear waves in single crystal silicon is about 4500-6000 m / s. Using rotating Y-cut X-propagation LiTaO3 or LiNbO3 as the piezoelectric layer, rotating Y-cut X-propagation quartz as the dielectric layer, and single crystal silicon as the substrate can basically meet the above speed requirements.

[0076] In some preferred embodiments, by selecting appropriate materials, the speed V2 of the body wave propagating in the dielectric film layer is greater than 1.05 times the speed of the body wave propagating in the piezoelectric film layer or greater than 1.05 times the speed of the surface acoustic wave propagating in the piezoelectric film layer, so that the body wave or surface acoustic wave with a smaller frequency can be confined in the piezoelectric film layer and the dielectric film layer; and / or the propagation speed of the body wave in the substrate is less than or equal to V2, which can further reduce the starting frequency of the body wave leaking from the substrate. In this way, the intensity of the waveguide mode can be further weakened on the basis of not affecting the main mode of the surface acoustic wave resonator as little as possible, thereby further reducing the influence of the high-frequency stray mode caused by the waveguide mode on the resonator performance.

[0077] In some embodiments, the material used for the substrate includes but is not limited to silicon, gallium arsenide, etc.

[0078] In some embodiments, the material used for the substrate includes single crystal silicon Si. Single crystal silicon is a form of single element silicon, which is a substance formed by silicon atoms in a certain arrangement.

[0079] like Figure 3 As shown in the right figure, quartz is used as the substrate in the related technology. The thermal conductivity of quartz is less than 3W / (m·K) in the range of 20-400℃, which is a low thermal conductivity material. When higher power is loaded on this resonant device, there is a higher risk of heat accumulation damage.

[0080] The thermal conductivity of single crystal silicon is about 150W / (m·K), which is much greater than the thermal conductivity of quartz. Therefore, using single crystal silicon Si as a substrate can not only make the body wave with the target frequency (for example, the body wave with a frequency greater than 1.05 times the resonant frequency of the surface acoustic wave) leak from the substrate, but also improve the problem of low thermal conductivity of the resonator and enhance the heat dissipation capacity of the substrate due to the good thermal conductivity of the single crystal silicon Si substrate compared to using quartz as a substrate.

[0081] like Figure 3 As shown in the left picture, based on the relevant technology, the quartz substrate in the original solution is changed to a quartz thin film layer (represented as a quartz layer in the figure), and the substrate is changed to a silicon substrate. This solution can inherit most of the advantages of the original solution while improving the heat dissipation capacity of the substrate.

[0082] like Figure 4 As shown, Figure 4 This is a temperature distribution diagram of the core chip of a duplexer using a quartz substrate when the power is loaded at 30dBm (1W). Figure 5 As shown, Figure 5 Yes Figure 4After the corresponding duplexer substrate is replaced with a quartz film layer / silicon substrate, the temperature distribution diagram of the core chip is loaded at the same power. It can be seen that after using the quartz film layer / silicon substrate, the maximum temperature of the core chip is significantly reduced, and the temperature gradient inside the core chip is also significantly reduced. Therefore, after switching to a quartz film layer / silicon substrate, the power tolerance of the device will be greatly improved.

[0083] In some embodiments, the propagation direction of the surface acoustic wave is parallel to the single crystal silicon substrate. <110> The directions within a first preset angle offset range of the crystal orientation family are parallel.

[0084] The structure of a single crystal silicon is a cube with six equivalent <100> Crystal orientation and twelve equivalent <110> Crystal direction, <110> The atoms in the crystal direction are arranged relatively closely, the atomic density is the highest, and the propagation direction of the surface acoustic wave is consistent with the single crystal silicon substrate. <110> The directions within the first preset angle offset range of the crystal orientation family are parallel, which can further reduce the propagation speed of the body wave in the single crystal silicon, which helps the body wave propagating in the dielectric thin film layer to leak to the substrate, thereby weakening the intensity of the waveguide mode, thereby reducing the influence of the high-frequency stray mode caused by the waveguide mode on the resonator performance.

[0085] In some embodiments, the first preset angle offset range includes 170° to 180° or 0° to 10°.

[0086] In some embodiments, the cut plane of the single crystal silicon substrate includes a cut plane within a second preset angle offset range of the normal to the {001} crystal plane family, or a cut plane within a second preset angle offset range of the normal to the {110} crystal plane family, or a cut plane within a second preset angle offset range of the normal to the {111} crystal plane family.

[0087] A crystal plane can refer to a plane containing any three non-collinear lattice points, which is a two-dimensional lattice containing an infinite number of lattice points. Interplanar spacing can refer to a set of crystal planes with an index of (hkl), and the distance between two adjacent crystal planes is called interplanar spacing. A crystal plane family can refer to a set of crystal planes with the same atomic arrangement and equal interplanar spacing in a crystal, but different spatial orientations, represented by {hkl}. In a cubic crystal, the crystal direction [hkl] with the same index as the crystal plane (hkl) is the normal direction of the crystal plane, i.e., the normal direction.

[0088] The crystal plane family {001} includes (100), (001) and (010) cross sections; the {110} crystal plane family includes (110), (011) and (101) cross sections. The cross sections within the second preset angle offset range of the normal direction of the {100} crystal plane family, or the cross sections within the second preset angle offset range of the normal direction of the {110} crystal plane family, or the cross sections within the second preset angle offset range of the normal direction of the {111} crystal plane family, all of which include the crystal plane family <110> , the requirements can be met if both the crystal plane family and the crystal orientation family meet the settings at the same time.

[0089] In some embodiments, the second preset angle offset range includes 0° to 5° or 175° to 180°.

[0090] For example, a cut plane within the second preset angle offset range of the normal to the {100} crystal plane family of a single crystal silicon substrate may be understood as a cut plane offset within the range of 0° to 5° or 175° to 180° based on the normal to the cut plane included in the {001} crystal plane family.

[0091] The substrate is made of single crystal silicon, which can satisfy the requirement that the speed of body wave propagation in the substrate is less than or equal to 1.5V2, and the cut surface of the single crystal silicon is a cut surface within the second preset angle offset range of the normal to the {001} crystal plane family, or a cut surface within the second preset angle offset range of the normal to the {110} crystal plane family, or a cut surface within the second preset angle offset range of the normal to the {111} crystal plane family, which is beneficial to reducing the starting frequency of body wave leakage from the substrate, thereby weakening the intensity of the waveguide mode and reducing the influence of high-frequency stray modes caused by the waveguide mode on the resonator performance.

[0092] In some embodiments, the Euler angle of the single crystal silicon substrate is (45°±5°, 0±5°, 0±5°), (0±5°, 90°±5°, 45°±5°), (±5°, -54.7±5°, -135°±5°) or (0±5°, 54.7°±5°, 45°±5°). The Euler angle describes the orientation of the single crystal material. When the orientation of the single crystal silicon substrate is within the above ranges, it helps the high-frequency waveguide mode to leak into the substrate, reduces the intensity of the waveguide mode in the dielectric film layer and the piezoelectric film layer, and can improve the suppression effect of the waveguide mode, thereby further reducing the influence of the high-frequency stray mode on the resonator performance.

[0093] Figure 1 A coordinate system xyz is shown in the figure. The z direction is the surface normal of the resonator, pointing from the substrate side to the piezoelectric film layer side; the x direction is the propagation direction of the surface acoustic wave, parallel to the upper surface of the piezoelectric film layer and perpendicular to the length direction of the metal electrode (aperture direction); the y direction is the aperture direction, perpendicular to the paper (or perpendicular to the screen) in the view. The coordinate system xyz conforms to the right-hand system (RHS).

[0094] Since the material properties of single crystals are closely related to the crystal orientation. In order to clarify the orientation relationship of each single crystal material in the resonator, the Euler angles (ω, μ, φ) are used to describe the orientation of the single crystal material. For crystals, Miller indices and crystal direction indices are usually used to determine the crystal planes and crystal directions, which can also determine the orientation of the crystal. It should be pointed out that there are many ways to describe the crystal orientation, and equivalent description methods will be deemed to be consistent with the embodiments of the present application.

[0095] In the embodiment of the present application, the Euler angles (ω, μ, φ) are defined as follows: First, a set of axes X, Y, and Z are taken as the basis, which are the crystal axes of the single crystal material (i.e., the crystal coordinate system). The first angle ω specifies the amount of rotation of the X-axis and the Y-axis around the Z-axis (the counterclockwise rotation angle around the axis is specified to be positive, and the clockwise rotation angle is specified to be negative). At this time, the X-axis rotates around the Z-axis in the direction of the Y-axis; accordingly, a new set of axes X', Y', and Z' appear, where Z=Z'. In further rotation, the Z'-axis and the Y'-axis rotate around the X'-axis by an angle μ. In this case, the Y'-axis rotates around the X'-axis in the direction of the Z'-axis; accordingly, a new set of axes X", Y", and Z" appear, where X'=X". In the third rotation, the X" axis and the Y" axis rotate around the Z" axis by an angle φ. At this time, the X" axis rotates around the Z" axis in the direction of the Y" axis, and a new set of axes X"', the third Y"', and Z"' appear accordingly, where Z" = Z"'; in this case, the X"' axis and the Y"' axis are parallel to the surface of the substrate, and the Z"' axis is perpendicular to the substrate surface; the X"' axis points to the propagation direction of the sound wave. At this time, the coordinate system X"'Y"'Z"' is Figure 1 The coordinate systems xyz in the matrix coincide with each other, and x=X”′, y=Y”′, z=Z”′.

[0096] In addition, when using Euler angles to describe the orientation of a crystal is not intuitive enough, the rotation angle of a single axis is often used to represent the tangent angle. For example: The first direction X represents the normal of the section, and the second direction Y represents the propagation direction of the sound wave. and β represent the angles of rotation around a specific axis. In this example, the X axis rotates around a certain axis. After the angle, the Y axis is still in the section, so the rotation axis is the Y axis. Then the propagation direction is the Y axis rotated around the section normal by an angle of β. If and β are 0 and can be omitted.

[0097] It can be understood that the energy of the main mode of the surface acoustic wave of the surface acoustic wave resonator (referred to as the main mode) is mainly confined within a shallow range of the surface. When the dielectric film layer reaches a certain thickness, the characteristics of the main mode will not change. Therefore, selecting a suitable material as the dielectric film layer and the dielectric film layer having an appropriate thickness can well constrain the energy of the main mode.

[0098] For example, see Figure 6 , Figure 6 yes Figure 3 Schematic diagram of the admittance simulation comparison between the quartz substrate solution and the quartz film / silicon substrate solution, where the upper figure is the admittance curve and the lower figure is the real part of the admittance curve. Figure 3 The main parameters of the resonator of the quartz substrate scheme in the middle right figure are: p=1μm, λ=2μm, electrode material Al, DF=0.5, electrode thickness 0.08λ, piezoelectric layer is 42°YX-LiTaO3, thickness 0.3λ, substrate is quartz, and the cut type is 69°Y90°X. Figure 3 The main parameters of the resonator of the quartz thin film layer / silicon substrate solution in the middle left figure are: p=1μm, λ=2μm, electrode material Al, DF=0.5, electrode thickness 0.08λ, piezoelectric layer is 42°YX-LiTaO3, thickness is 0.3λ, the cut of the quartz layer is 69°Y90°X, thickness is 1λ, and the cut of the silicon substrate is 45°X90°Z.

[0099] from Figure 6 As can be seen from the figure, the main mode characteristics of the two schemes are almost exactly the same. However, more high-frequency stray modes appear in the quartz film layer / silicon substrate scheme. High-frequency stray modes are usually not required in engineering applications and need to be moved, suppressed or removed.

[0100] Research has found that high-frequency heterogeneous modes have many forms, one of which is a waveguide mode formed inside each film layer or multiple film layers on the substrate.

[0101] Figure 7 The left figure is a schematic diagram of the waveguide mode propagating in a single-layer film (i.e., piezoelectric layer). Figure 7 The figure on the right is a schematic diagram of a waveguide mode propagating in a multilayer thin film (piezoelectric layer and dielectric layer) (the reflection and transmission relationship within the layer is not shown in the schematic diagram).

[0102] One way to suppress the waveguide mode is to allow the energy of the waveguide mode to leak into the substrate, thereby reducing the Q value of the waveguide mode. Figure 8 The figure shows the leakage characteristics of waveguide modes in high acoustic velocity substrates (i.e., the velocity of the bulk wave in the substrate is higher than the velocity of the bulk wave in the dielectric thin film layer) and low acoustic velocity substrates (i.e., the velocity of the bulk wave in the substrate is lower than the velocity of the bulk wave in the dielectric thin film layer).

[0103] If a low-acoustic-velocity substrate is used, all acoustic waves (including the main mode of surface acoustic waves) reaching the interface between the low-acoustic-velocity substrate and the dielectric layer will leak. To avoid leakage of the main mode, the total thickness of the film layer outside the substrate must be thick enough so that the energy distribution position of the main mode cannot reach the substrate.

[0104] If a high acoustic velocity substrate is used, only the incident angle γ of the waveguide mode is less than a certain critical angle γ c , the body wave will leak. Since the propagation direction of the main mode is parallel to the upper surface, the corresponding γ=90°>γ c , so the main mold will not leak.

[0105] Critical Angle γ c The determination of can refer to the Snell theorem in optics. The projections of the wave vectors of the incident, reflected, and transmitted sound waves on the interface are equal. That is, |K i |sinγ=|K t |sinψ,|K i |sinγ c =|K t |sin90°, so sinγ c =|K t | / |K i |(K i , K t are the wave vectors of the incident wave and the transmitted wave respectively), where ψ is the angle between the body wave and the interface normal after transmission.

[0106] The essence of the waveguide mode is that the body wave generated on the surface is reflected multiple times in the surface layer to form resonance. There are two ways to generate this body wave: surface wave scattering and IDT direct excitation body wave. The incident angle γ of these two body waves is related to the operating frequency. Not all body waves can form a waveguide mode. Only when the product of the vertical projection of the body wave vector and the thickness of the film plus the sum of the phase shift caused by the upper and lower interface reflections is equal to an integer multiple of 2π can a waveguide mode be formed.

[0107] In practical applications, the frequency of the waveguide mode needs to be higher than the starting frequency of the bulk wave leakage, so that the intensity of the waveguide mode can be weakened due to the bulk wave leakage, thereby reducing the impact of the waveguide mode on the application. This effect can be achieved by selecting appropriate materials and making the sound velocity or thickness of each film layer meet specific conditions.

[0108] When the film material is fixed, the smaller the film thickness is, the greater the frequency of the waveguide mode is.

[0109] Figure 9a is a schematic diagram of the relationship between the waveguide mode position and the film thickness. It can be understood that the film thickness can be regarded as at least one of the piezoelectric film thickness, the dielectric film thickness, and the total thickness of the piezoelectric film layer and the dielectric film layer. The waveguide mode position is the frequency position at which the waveguide mode is formed, which is given by Figure 9a It can be seen that as the thickness of the film layer decreases, the position of the waveguide mode moves toward high frequency. When the position of the waveguide mode is on the high frequency side of the starting frequency of the body wave leakage, the intensity of the waveguide mode is significantly reduced. Figure 9bThis is a schematic diagram of the relationship between the waveguide mode Q value and the film thickness, which further compares the two examples of film thicknesses of 1μm and 0.6μm.

[0110] from Figure 9b It can be seen that when the film thickness is 0.6μm, the frequency of the waveguide mode is higher than the starting frequency of the bulk wave leakage, and the Q value of the waveguide mode will be greatly reduced. When the film thickness is 1μm, the frequency of the waveguide mode is lower than the starting frequency of the bulk wave leakage, and the Q value intensity of the waveguide mode is still large. Therefore, by reducing the film thickness, the Q value of the waveguide mode can be reduced, thereby weakening or avoiding the influence of the waveguide mode on the device performance.

[0111] When the piezoelectric layer and the dielectric layer are fixed, the frequency position of the waveguide mode remains roughly unchanged (actually it will be affected by some substrates), but the starting frequency of the body wave leakage increases with the increase of the substrate sound velocity and will change greatly. Fig.10a This is a schematic diagram of the relationship between the change in substrate acoustic velocity and the starting frequency of body wave leakage. Fig.10b It is the relationship between the change of substrate sound velocity and the change of waveguide mode Q value. When the substrate sound velocity is large (for example, V = 5630m / s or V = 5340m / s), the starting frequency of bulk wave leakage will move to high frequency, the frequency of waveguide mode is lower than the starting frequency of bulk wave leakage, and the amplitude and Q value of waveguide mode are still relatively large, indicating that the degree of waveguide mode leakage to the substrate is small or even non-existent; when the substrate sound velocity is small (for example, V = 4870m / s), the starting frequency of bulk wave leakage will move to high frequency, the frequency of waveguide mode is higher than the starting frequency of bulk wave leakage, and the amplitude and Q value of waveguide mode are small, indicating that the degree of waveguide mode leakage to the substrate is large.

[0112] Figure 11a-Figure 11c It is the change of the sound velocity of single crystal silicon in certain specific directions. Since the dielectric film layer (such as the quartz film layer) has the ability to constrain the main mode on the surface of the piezoelectric film layer, the introduction of the silicon substrate should avoid constraining the waveguide mode on the surface of the piezoelectric film layer as much as possible. To achieve this effect, it is necessary to select a cut type and propagation direction with a lower propagation speed (i.e., sound speed) of the body wave on the silicon substrate.

[0113] For example, from the sound speed in the three cut planes of Si(100), Si(110) and Si(111), it can be seen that the lowest sound speed is about 4680m / s, and the corresponding propagation direction is <110> Crystalline orientation family. Si(100), Si(110) and Si(111) crystal planes are available in <110> The crystal orientation of a crystal family.

[0114] Fig.12The harmonic admittance diagram of the surface acoustic wave when the single crystal silicon substrate is cut into different shapes. Specifically, the single crystal silicon is used as the substrate, and the silicon (100), (110) and (111) cut planes are the upper surfaces of the substrate. <110> The susceptance and conductance of the surface acoustic wave when the crystal orientation family is parallel to the propagation direction of the surface acoustic wave. Fig.12 It can be seen that the starting frequency of the bulk wave leakage from the substrate is about 2.35GHz, and the frequency position of the waveguide mode is about 2.6GHz, which is greater than the starting frequency of the bulk wave leakage. From the admittance curves corresponding to the four sections, the peak positions of the waveguide mode are relatively rounded and do not show obvious peaks, indicating that the intensity (amplitude) of the waveguide mode has been greatly reduced. Moreover, among the four sections, the substrate with a (111) section performs better, and the (111) section can be preferred in practical applications.

[0115] In some embodiments, the thickness H of the piezoelectric film layer or the dielectric film layer satisfies the following relationship:

[0116]

[0117] Among them, α is the ratio of phase shift to π, f r represents the resonant frequency of the surface acoustic wave. If H represents the thickness of the piezoelectric film layer, then θ represents the angle between the propagation direction of the body wave in the piezoelectric film layer and the surface of the piezoelectric film layer. V B (θ) represents the propagation velocity of the bulk wave in the piezoelectric film layer. If H represents the thickness of the dielectric film layer, then θ represents the angle between the propagation direction of the bulk wave in the dielectric film layer and the surface of the dielectric film layer, V B (θ) represents the propagation speed of the body wave in the dielectric thin film layer, and η is a constant greater than 1. The above phase shift refers to the additional phase shift caused by the reflection of the body wave at the upper and lower interfaces when the body wave propagates in the layer. If H represents the thickness of the piezoelectric thin film layer, α represents the ratio of the additional phase shift caused by the reflection of the body wave at the upper and lower interfaces of the piezoelectric thin film layer when the body wave propagates in the piezoelectric thin film layer to π; if H represents the thickness of the dielectric thin film layer, α represents the ratio of the additional phase shift caused by the reflection of the body wave at the upper and lower interfaces of the dielectric thin film layer when the body wave propagates in the dielectric thin film layer to π.

[0118] In some cases, although the resonance formed by body waves in the surface film (piezoelectric film layer and / or dielectric film layer) has been suppressed to a weaker level, in some applications, such as in carrier aggregation (CA) applications, the weaker resonance may still interfere with other frequency bands.

[0119] The resonance frequency of the body wave propagating toward the substrate in the surface film (e.g., waveguide mode) is closely related to the film thickness. For the resonance (e.g., waveguide mode) where energy leakage has occurred, the resonance range must include all the films above the interface on the substrate, so the thickness of the film will affect the frequency of the resonance (e.g., waveguide mode) formed by the body wave in the surface film.

[0120] In order to avoid the resonance formed by the body wave in the surface film from interfering with other frequency bands as much as possible, the frequency position of the resonance can be changed, that is, the frequency of the resonance formed by the body wave in the surface film is kept at a certain distance from the target frequency band. In the embodiment of the present application, the frequency of the resonance can be changed by controlling the thickness of the piezoelectric film layer and / or the dielectric film layer.

[0121] Taking the waveguide mode as an example, in practical applications, the frequency fg of the waveguide mode is generally η times the resonant frequency fr of the main mode, that is, fg = η × fr.

[0122] The propagation velocity V of body waves in different directions in anisotropic materials (including piezoelectric materials) B It can be determined by the Christoph equation as follows.

[0123]

[0124] in:

[0125]

[0126] Γ i4 =e kij l k l j

[0127]

[0128] (i, j, k, l = 1, 2, 3)

[0129] The formula uses Einstein notation, that is, if the same subscript appears repeatedly in the formula, it means that all possible combinations of the subscript are summed; ρ is the material density, is the fourth-order elastic constant tensor under short-circuit state; δ ij is the Kronecker symbol, when i=j,δ ij =1; otherwise δ ij =0;e kij is the third-order piezoelectric stress constant matrix; is the second-order dielectric constant tensor in the mechanical clamping state; l i , l j and l k It is the direction cosine of the propagation direction of the body wave and the coordinate system (the coordinate system can be selected as the crystal coordinate system or the global coordinate system).

[0130] The propagation velocity V of the body wave can be established by the Christoph equation B The relationship between the propagation direction of the body wave.

[0131] like Fig.13 As shown, Fig.13 The left figure is a backscattered body wave radiation model, which includes a piezoelectric film layer (represented as a piezoelectric layer in the figure) and a substrate (represented as a high acoustic velocity substrate in the figure). The metal electrodes of the metal electrode layer are arranged in a certain spatial period, the spatial period is p, and λ=2p is defined. The surface acoustic wave is incident on two adjacent fingers in succession and radiates body waves to the substrate. The radiation angle is θ, which is the angle between the propagation direction of the body wave in the piezoelectric film layer and the surface of the piezoelectric film layer. Therefore, the propagation velocity of the body wave is defined as V B The relationship between V and θ is B (θ), that is, the propagation velocity of the body wave when the angle between the propagation direction of the piezoelectric film layer and the surface of the piezoelectric film layer is θ, and the function F(θ)=V B (θ) / cos(θ), G(θ)=V B (θ) / sin(θ).

[0132] The condition for the radiation enhancement of backscattered body waves is that the body waves backscattered by the surface acoustic wave after passing through two adjacent fingers have the same phase or a phase difference of an integer multiple of 2π n1 in the plane perpendicular to the propagation direction of the backscattered body waves. Therefore, the condition for the radiation enhancement of backscattered body waves can be expressed by the following formula:

[0133]

[0134] Using Vs = λ s f and V B =λ B f,λ s represents the wavelength of the surface acoustic wave, Vs represents the propagation speed of the surface acoustic wave, λ B represents the wavelength of the body wave, V B represents the propagation speed of the body wave, f represents the frequency (i.e., the driving frequency of the resonator, which is the frequency of the surface acoustic wave and the frequency of the body wave), the above formula can be simplified as follows:

[0135]

[0136] Assuming that the propagation velocity Vs of the surface acoustic wave changes very slowly with frequency, that is, it is approximately considered that Vs does not change with frequency, the above formula can be further written as the following formula (1):

[0137]

[0138] From formula (1), we can get the frequency of the backscattered body wave and the resonant frequency of the surface acoustic wave: r , F(θ) and p.

[0139] Fig.13 The figure on the right refers to the stimulated body wave radiation model. The direct stimulated body wave radiation enhancement condition can be expressed by the following formula:

[0140] 2p·cosθ=n2·λ B

[0141] Wherein, n2 is an integer.

[0142] V B =λ B Substituting f into the above formula, we can get the following formula (2):

[0143]

[0144] From formula (2), we can get the relationship between the frequency of the excited body wave and F(θ) and p.

[0145] Fig.14 It is a schematic diagram of the resonance of the waveguide mode. The body wave is reflected twice by the upper and lower interfaces, and the phase introduced by the reflection differs from the phase of the original incident wave in the plane perpendicular to the propagation direction by an integer multiple n3 of 2π. When the waveguide mode is only formed in the piezoelectric film layer (piezoelectric layer), let the thickness of the piezoelectric film layer be H, the radiation angle of the body wave be θ, and the angle between the original incident wave of the body wave and the normal be γ (complementary to θ).

[0146]

[0147] Wherein, n3 is an integer.

[0148] or

[0149] |K1|sinθ·2H-απ=|K1|cosγ·2H-απ=2n3π

[0150] Here, |K1| represents the wave vector of the body wave.

[0151] The above two formulas both express the relationship between the condition for the bulk wave to form a waveguide mode and the thickness of the piezoelectric film layer.

[0152] Using V B =λ B ·f, the above two formulas can be simplified to the following formula (3):

[0153]

[0154] From formula (3), we can get the relationship between the frequency of the waveguide mode, the thickness H of the piezoelectric film layer and the radiation angle θ of the waveguide mode.

[0155] In practical applications, the waveguide mode is generally at the resonant frequency f of the surface acoustic wave. r In order to avoid the influence of the waveguide mode on the resonator performance, the frequency of the waveguide mode (i.e., the frequency at which the body wave forms resonance) needs to be moved to the resonant frequency f r Therefore, the frequency of the waveguide mode f g Need to be set to the resonant frequency f of the surface acoustic wave r η times, we get formula (4): g ≥η×f r , since the frequency of the body wave is the driving frequency, f g This is f in the above formula. When considering the backscattered body wave, substitute formula (4) into formula (1) and take n1 = 1 (investigating the case of single reflection of the body wave), we can obtain the resonant frequency f r The F(θ) of the waveguide mode generated at the position η times of the resonant frequency f of the surface acoustic wave r And the relationship between the spatial period p:

[0156]

[0157] Therefore, in a certain resonator, if its resonant frequency and spatial period are determined, then the value of F(θ) is also determined, so the propagation speed of the waveguide mode of the resonator can be obtained. B and radiation angle θ. Since G(θ)=V B (θ) / sin(θ), so it can be determined that the thickness H of the piezoelectric film layer of the resonator must satisfy the following relationship:

[0158]

[0159] When directly exciting the body wave, formula (4) is substituted into formula (2), and when n2=1 (the case of single reflection of the body wave is discussed), the condition that the thickness H of the piezoelectric film layer satisfies can also be obtained. Since its value is greater than the above relationship, when the thickness of the piezoelectric film layer satisfies the above relationship, the waveguide mode formed by the direct stimulation of the body wave will also move to the resonant frequency f r The position is more than η times, so it is not described in detail.

[0160] In some embodiments, the value range of η is [1.05, 1.2], that is, greater than or equal to 1.05 and less than or equal to 1.2.

[0161] In the present application, since α represents the ratio of phase shift to π, the value range has a large interval. In the preferred embodiment of the present application, the value range of α is [0,1], so the relationship between the thickness of the piezoelectric film layer and / or the dielectric film layer and the main mode resonant frequency of the surface acoustic wave can be obtained as follows:

[0162]

[0163] On the basis of limiting the acoustic velocity relationship, by limiting the thickness of the piezoelectric film layer and / or the dielectric film layer, the influence of the waveguide mode on the main mode of the surface acoustic wave can be further reduced.

[0164] The above derivation is based on the case where there is only a single piezoelectric thin film layer on the substrate. The same method can be used to derive the case where there are multiple thin film layers on the substrate. It is only necessary to accumulate the phase difference generated by the wave vectors of each layer in the vertical direction and add a -απ phase.

[0165] |K1|cosγ·2H1+|K2|cosψ·2H2-απ=2n2π

[0166] Among them, |K2| is the wave vector of the refracted wave, and ψ is the angle between the refracted wave and the normal.

[0167] Therefore, on the basis that the speed V2 of body wave propagation in the dielectric film layer is greater than the speed of body wave propagation in the piezoelectric film layer or greater than the speed of surface acoustic wave propagation in the piezoelectric film layer, and the speed of body wave propagation in the substrate is less than or equal to 1.5V2, after the piezoelectric film layer and / or the dielectric film layer satisfies the above relationship, not only can the waveguide mode be leaked to the substrate, but the frequency of the waveguide mode can also be moved to a position above the target frequency, thereby further reducing the influence of the waveguide mode on the main mode of the surface acoustic wave and optimizing the resonator performance.

[0168] like Fig.15 As shown in the figure, taking the waveguide mode as an example, the influence of the film thickness on the frequency of the waveguide mode. It can be seen that when the total thickness of the piezoelectric film layer (whose material is single crystal LiTaO3, abbreviated as LT) and the dielectric film layer (whose material is single crystal quartz, abbreviated as quartz) increases, the frequency of the waveguide mode will move in the direction of decreasing frequency; when the total thickness of the piezoelectric film layer and the dielectric film layer decreases, the frequency of the waveguide mode will move in the direction of increasing frequency; although the thickness of the piezoelectric film layer and the dielectric film layer are not equal, when the total thickness of the piezoelectric film layer and the dielectric film layer are equal, the frequency of the waveguide mode basically does not change much.

[0169] That is to say, in the case of a structure including a dielectric film layer between the substrate and the piezoelectric film layer, the total thickness of the piezoelectric film layer and the dielectric film layer is the sum of the thickness of the piezoelectric film layer and the thickness of the dielectric film layer, and the thickness of the piezoelectric film layer and the thickness of the dielectric film layer are respectively obtained by the above-mentioned formula for thickness H.

[0170] In some embodiments, if there is a multi-layer film structure between the substrate and the piezoelectric film layer, the sum of the thicknesses of the piezoelectric film layer and the multiple film structures can also be calculated using the above formula.

[0171] In some embodiments, the total thickness of the dielectric film layer and the piezoelectric film layer is less than λ, where λ=2p, and p represents the spatial period of the metal electrodes on the metal electrode layer.

[0172] Combination Figure 3 By further limiting the total thickness of the dielectric film layer and the piezoelectric film layer, on the one hand, the frequency of the resonance formed by the body wave in the surface film can be changed, and on the other hand, the Figure 3 Other advantages of the quartz substrate in the original scheme on the right.

[0173] In some embodiments, the total thickness of the dielectric film layer and the piezoelectric material layer is less than 0.6λ. The total thickness of the dielectric film layer and the piezoelectric material layer is less than 0.6λ, which can further move the frequency of the waveguide mode toward a larger frequency, further reducing the influence of the waveguide mode on the main mode of the surface acoustic wave, and can reduce the thickness of the resonator, thereby miniaturizing the resonator to a certain extent.

[0174] In some embodiments, the material of the dielectric film layer includes single crystal quartz, and the material of the piezoelectric film layer includes one of LiTaO3 and LiNbO3, such as single crystal LiTaO3 or single crystal LiNbO3.

[0175] Lithium tantalate (LiTaO3, LT) and lithium niobate (LiNbO3, LN) crystals are multifunctional crystal materials that integrate piezoelectric, ferroelectric, pyroelectric, acousto-optic and electro-optic properties, and are widely used in the industry. In particular, lithium tantalate (LiTaO3) crystals have high application value: LiTaO3 crystals have high chemical stability (insoluble in water), Curie point is higher than 600℃, depolarization is not easy to occur, dielectric loss is low, and the detection rate has high merit, making them the best choice for pyroelectric infrared detector application materials. Polished LT wafers are widely used in the manufacture of electronic communication devices such as resonators, filters, and transducers. In particular, they are used to manufacture high-frequency surface acoustic wave devices due to their good electromechanical coupling, temperature coefficient and other comprehensive properties, and are used in many high-end communication fields such as mobile phones, walkie-talkies, satellite communications, aerospace, surface acoustic wave devices, optical communications, lasers and optoelectronics.

[0176] In some embodiments, the material of the dielectric thin film layer includes single crystal quartz, and the Euler angles of the single crystal quartz are (ω1, μ1, φ1), wherein ω1 ranges from -5° to 5°, μ1 ranges from -85° to -5°, and φ1 ranges from 85° to 95° or -95° to -85°. Within this range, the transverse mode of the resonator can be better suppressed.

[0177] In some embodiments, the material of the piezoelectric film layer includes LiTaO3, and the Euler angle of the piezoelectric film layer is (ω2, μ2, φ2), wherein ω2 ranges from -5° to 5°, μ2 ranges from -75° to -25°, and φ2 ranges from -5° to 5° or 175° to 185°. Within this range, the resonator has better electrical performance.

[0178] In some embodiments, the material of the piezoelectric film layer includes LiNbO3, and the Euler angle of the piezoelectric film layer is (ω3, μ3, φ3), wherein ω3 ranges from -5° to 5°, μ3 ranges from -110° to -25°, and φ3 ranges from -5° to 5° or 175° to 185°. Within this range, the resonator has good electrical performance.

[0179] The piezoelectric film layer / dielectric film layer / substrate (e.g., αYX-LiTaO3 / βY±90X-Quartz / Si) of the embodiment of the present application can realize a concave or flat bottom of the main mode dispersion curve in a relatively large range, such as Fig.16 As shown, Fig.16 It is a typical dispersion curve and slowness curve. This type of dispersion curve can easily achieve transverse mode suppression. To a certain extent, it can replace the transverse mode suppression structure set on the IDT structure, such as widening or thickening part of the electrode finger, or setting a low sound velocity dielectric layer in part of the IDT area or setting a high sound velocity dielectric layer in part of the IDT area to form a piston mode, thereby reducing the complexity of the IDT design or realizing high-frequency applications of the resonator.

[0180] The present application also provides another resonator. It should be noted that for the contents of the resonator in the embodiment of the present application that are the same as the above-mentioned resonator, please refer to the detailed description of the above-mentioned resonator, which will not be repeated here.

[0181] The resonator comprises: a substrate, a quartz film layer, a piezoelectric film layer, and a metal electrode layer. The quartz film layer is arranged on the substrate; the piezoelectric film layer is arranged on the quartz film layer; and the metal electrode layer is arranged on the piezoelectric film layer.

[0182] The acoustic waves of the resonator during operation include surface acoustic waves and bulk waves. The quartz film layer constrains the surface acoustic waves within the surface range of the piezoelectric film layer. The bulk waves propagate in at least one of the substrate, the quartz film layer and the piezoelectric film layer. The thickness H of the piezoelectric film layer and / or the quartz film layer satisfies the following relationship:

[0183]

[0184] Among them, α is the ratio of phase shift to π, f r represents the resonant frequency of the surface acoustic wave. If H represents the thickness of the piezoelectric film layer, then θ represents the angle between the propagation direction of the body wave in the piezoelectric film layer and the surface of the piezoelectric film layer. V B (θ) represents the propagation velocity of the bulk wave in the piezoelectric thin film layer. If H represents the thickness of the quartz thin film layer, then θ represents the angle between the propagation direction of the bulk wave in the quartz thin film layer and the surface of the quartz thin film layer, V B (θ) represents the propagation velocity of the bulk wave in the quartz thin film layer, and η is a constant greater than 1.

[0185] The resonator of the embodiment of the present application controls the thickness of the piezoelectric film layer and / or the quartz film layer to satisfy a certain relationship. In this way, the frequency of the waveguide mode can be changed without affecting the main mode of operation of the resonator, so that the frequency of the waveguide mode is moved to a position above the target frequency, thereby further reducing the influence of the waveguide mode on the main mode of the surface acoustic wave and optimizing the resonator performance.

[0186] In some embodiments, the thickness H of the piezoelectric film layer and / or the quartz film layer satisfies the following relationship:

[0187]

[0188] In some embodiments, the thickness of the piezoelectric film layer is greater than or equal to 0.1λ and less than or equal to 0.5λ; the thickness of the quartz film layer is greater than or equal to 0.1λ and less than or equal to 0.5λ, where λ=2p, and p represents the spatial period of the metal electrode on the metal electrode layer. In this way, the surface acoustic wave can be confined within the surface range of the piezoelectric film layer, and the frequency of the waveguide mode can be further moved to the direction of higher frequency, further reducing the influence of the waveguide mode on the main mode of the surface acoustic wave, and the thickness of the resonator can be reduced, which can achieve the miniaturization of the resonator to a certain extent.

[0189] In some embodiments, the total thickness of the dielectric film layer and the piezoelectric film layer is less than λ, where λ=2p, and p represents the spatial period of the metal electrodes on the metal electrode layer.

[0190] In some embodiments, the total thickness of the dielectric film layer and the piezoelectric material layer is less than 0.6λ. The total thickness of the dielectric film layer and the piezoelectric material layer is less than 0.6λ, which can further move the frequency of the waveguide mode toward a larger frequency, further reducing the influence of the waveguide mode on the main mode of the surface acoustic wave, and can reduce the thickness of the resonator, thereby miniaturizing the resonator to a certain extent.

[0191] In some embodiments, the material used for the substrate includes single crystal silicon.

[0192] In some embodiments, the propagation direction of the surface acoustic wave is parallel to the single crystal silicon substrate. <110> The directions within a first preset angle offset range of the crystal orientation family are parallel.

[0193] In some embodiments, the Euler angle of the silicon substrate is (45°±5°, 0±5°, 0±5°), (0±5°, 90°±5°, 45°±5°), (±5°, -54.7±5°, -135°±5°) or (0±5°, 54.7°±5°, 45°±5°).

[0194] The present application also provides another resonator. It should be noted that for the contents of the resonator in the embodiment of the present application that are the same as the above resonator, please refer to the detailed description of the above resonator, which will not be repeated here.

[0195] The resonator comprises: a silicon substrate, a quartz film layer, a piezoelectric film layer and a metal electrode layer. The quartz film layer is arranged on the silicon substrate; the piezoelectric film layer is arranged on the quartz film layer; and the metal electrode layer is arranged on the piezoelectric film layer.

[0196] The acoustic waves of the resonator during operation include surface acoustic waves and bulk waves. The quartz film layer constrains the surface acoustic waves within the surface range of the piezoelectric film layer, and the bulk waves propagate in at least one of the silicon substrate, the quartz film layer, and the piezoelectric film layer. The propagation direction of the surface acoustic waves is consistent with the direction of the single crystal silicon substrate. <110> The directions within a first preset angle offset range of the crystal orientation family are parallel.

[0197] The resonator of the embodiment of the present application uses a silicon substrate and a quartz thin film layer to make the propagation direction of the surface acoustic wave consistent with the single crystal silicon substrate. <110> The directions within the first preset angle offset range of the crystal orientation family are parallel; this can reduce the propagation speed of the body wave in the single crystal silicon, which helps the body wave propagating in the dielectric film layer to leak to the substrate, thereby weakening the intensity of the waveguide mode, thereby reducing the impact of the high-frequency stray mode caused by the waveguide mode on the device performance.

[0198] In some embodiments, the first preset angle offset range includes 170° to 180° or 0° to 10°.

[0199] In some embodiments, the cut surface of the silicon substrate includes a cut surface within a second preset angle offset range of the normal direction of the {001} crystal plane family, or a cut surface within a second preset angle offset range of the normal direction of the {110} crystal plane family, or a cut surface within a second preset angle offset range of the normal direction of the {111} crystal plane family.

[0200] In some embodiments, the second preset angle offset range includes 0° to 5° or 175° to 180°.

[0201] In some embodiments, the material of the silicon substrate includes single crystal silicon, and the Euler angle of the silicon substrate is (45°±5°, 0±5°, 0±5°), (0±5°, 90°±5°, 45°±5°), (±5°, -54.7±5°, -135°±5°), or (0±5°, 54.7°±5°, 45°±5°).

[0202] In some embodiments, the total thickness of the quartz thin film layer and the piezoelectric material layer is less than λ, where λ=2p, and p represents the spatial period of the metal electrodes on the metal electrode layer.

[0203] In some embodiments, the total thickness of the quartz thin film layer and the piezoelectric material layer is less than 0.6λ.

[0204] In some embodiments, the material of the quartz thin film layer includes single crystal quartz, and the material of the piezoelectric thin film layer includes one of LiTaO3 and LiNbO3.

[0205] In some embodiments, the Euler angles of the quartz thin film layer are (ω1, μ1, φ1), wherein ω1 ranges from -5° to 5°, μ1 ranges from -85° to -5°, and φ1 ranges from 85° to 95° or -95° to -85°.

[0206] In some embodiments, the material of the piezoelectric film layer includes LiTaO3, and the Euler angle of the piezoelectric film layer is (ω2, μ2, φ2), where ω2 ranges from -5° to 5°, μ2 ranges from -75° to -25°, and φ2 ranges from -5° to 5° or 175° to 185°.

[0207] In some embodiments, the material of the piezoelectric film layer includes LiNbO3, and the Euler angles of the piezoelectric film layer are (ω3, μ3, φ3), where ω3 ranges from -5° to 5°, μ3 ranges from -110° to -25°, and φ3 ranges from -5° to 5° or 175° to 185°.

[0208] The present application also provides another resonator. It should be noted that for the contents of the resonator in the embodiment of the present application that are the same as the above resonator, please refer to the detailed description of the above resonator, which will not be repeated here.

[0209] The resonator comprises: a substrate, a dielectric film layer, a piezoelectric film layer, and a metal electrode layer. The dielectric film layer is arranged on the substrate; the piezoelectric film layer is arranged on the dielectric film layer; and the metal electrode layer is arranged on the piezoelectric film layer.

[0210] Among them, the sound waves when the resonator is working include surface acoustic waves and body waves. The dielectric film layer constrains the surface acoustic waves within the surface range of the piezoelectric film layer, and the body waves propagate in at least one of the substrate, the dielectric film layer and the piezoelectric film layer. The material used for the substrate can cause the body waves with a target frequency to leak in the substrate, and the target frequency is greater than the resonant frequency of the surface acoustic wave.

[0211] The resonator of the embodiment of the present application enables the material used for the substrate to cause a body wave with a target frequency to leak in the substrate, and the target frequency is greater than the resonant frequency of the surface acoustic wave. In this way, on the one hand, the energy of the body wave can be reduced, and on the other hand, the formation of a waveguide mode in the layer structure above the substrate can be avoided, thereby reducing the influence of the high-frequency stray mode caused by the waveguide mode on the device performance.

[0212] In some embodiments, the material used for the substrate includes single crystal silicon.

[0213] In some embodiments, the propagation direction of the surface acoustic wave is parallel to the single crystal silicon substrate. <110> The directions within a first preset angle offset range of the crystal orientation family are parallel.

[0214] In some embodiments, the thickness H of the piezoelectric film layer and / or the dielectric film layer satisfies the following relationship:

[0215]

[0216] Among them, α is the ratio of phase shift to π, f r represents the resonant frequency of the surface acoustic wave. If H represents the thickness of the piezoelectric film layer, then θ represents the angle between the propagation direction of the body wave in the piezoelectric film layer and the surface of the piezoelectric film layer. V B (θ) represents the propagation velocity of the bulk wave in the piezoelectric film layer. If H represents the thickness of the dielectric film layer, then θ represents the angle between the propagation direction of the bulk wave in the dielectric film layer and the surface of the dielectric film layer, V B (θ) represents the propagation velocity of body waves in the dielectric thin film layer, and η is a constant greater than 1.

[0217] In some embodiments, the total thickness of the dielectric film layer and the piezoelectric material layer is less than λ, where λ=2p, and p represents the spatial period of the metal electrodes on the metal electrode layer.

[0218] In some embodiments, the total thickness of the dielectric film layer and the piezoelectric material layer is less than 0.6λ.

[0219] In some embodiments, the material of the dielectric film layer includes single crystal quartz, and the material of the piezoelectric film layer includes one of LiTaO3 and LiNbO3.

[0220] In some embodiments, the speed V2 of body waves propagating in the dielectric film layer is greater than the speed of body waves propagating in the piezoelectric film layer or greater than the speed of surface acoustic waves propagating in the piezoelectric film layer, and the speed of body waves propagating in the substrate is less than or equal to 1.5V2.

[0221] The present application also provides a surface acoustic wave filter, which includes any of the above resonators.

[0222] The main features of SAW filters are: great design flexibility, analog / digital compatibility, excellent group delay time deviation and frequency selection (optional frequency range is 10MHz-3GHz), small input and output impedance errors, small transmission loss, good anti-electromagnetic interference (EMI) performance, high reliability, small size and light weight of manufactured devices, and the ability to achieve a variety of complex functions. The characteristics and advantages of SAW filters are in line with the requirements of modern communication system equipment and mobile communication for lightness, high frequency, digitization, high performance, and high reliability.

[0223] The present application also provides a radio frequency front-end module, which includes the above filter. The radio frequency front-end module may include an antenna terminal, a power amplifier, a low noise amplifier, a switch, a filter, etc., which are not specifically limited here.

[0224] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A resonator, characterized in that: The resonator comprises: substrate; A dielectric thin film layer is disposed on the substrate; A piezoelectric film layer is disposed on the dielectric film layer; A metal electrode layer, disposed on the piezoelectric film layer; Among them, the sound waves when the resonator is working include surface acoustic waves and body waves, the dielectric film layer constrains the surface acoustic waves within the surface range of the piezoelectric film layer, the body waves propagate in the substrate, the dielectric film layer and the piezoelectric film layer, the speed V2 of the body waves propagating in the dielectric film layer is greater than the speed of the body waves propagating in the piezoelectric film layer or greater than the speed of the surface acoustic waves propagating in the piezoelectric film layer, and the speed of the body waves propagating in the substrate is less than or equal to 1.5V2.

2. The resonator according to claim 1, characterized in that The propagation speed V2 of the body wave in the dielectric film layer is greater than 1.05 times the propagation speed of the body wave in the piezoelectric film layer or greater than 1.05 times the propagation speed of the surface acoustic wave in the piezoelectric film layer; and / or, the propagation speed of the body wave in the substrate is less than or equal to V2.

3. The resonator according to claim 1, characterized in that The material used for the substrate includes single crystal silicon.

4. The resonator according to claim 3, characterized in that The propagation direction of the surface acoustic wave is consistent with the single crystal silicon substrate. <110> The directions within a first preset angle offset range of the crystal orientation family are parallel.

5. The resonator according to claim 4, characterized in that The first preset angle offset range includes 170° to 180° or 0° to 10°.

6. The resonator according to claim 4, characterized in that The cut surface of the substrate includes a cut surface within a second preset angle offset range of the normal direction of the {001} crystal plane family, a cut surface within a second preset angle offset range of the normal direction of the {110} crystal plane family, or a cut surface within a second preset angle offset range of the normal direction of the {111} crystal plane family.

7. The resonator according to claim 6, characterized in that The second preset angle offset range includes 0° to 5° or 175° to 180°.

8. The resonator according to claim 3, characterized in that The Euler angle of the substrate is (45°±5°, 0±5°, 0±5°), (0±5°, 90°±5°, 45°±5°), (±5°, -54.7±5°, -135°±5°) or (0±5°, 54.7°±5°, 45°±5°).

9. The resonator according to claim 1, characterized in that The thickness H of the piezoelectric film layer and / or the dielectric film layer satisfies the following relationship: Among them, α is the ratio of phase shift to π, f r represents the resonant frequency of the surface acoustic wave, if H represents the thickness of the piezoelectric film layer, then θ represents the angle between the propagation direction of the body wave in the piezoelectric film layer and the surface of the piezoelectric film layer, V B (θ) represents the propagation speed of the bulk wave in the piezoelectric film layer. If H represents the thickness of the dielectric film layer, then θ represents the angle between the propagation direction of the bulk wave in the dielectric film layer and the surface of the dielectric film layer. V B (θ) represents the propagation speed of the body wave in the dielectric thin film layer, and η is a constant greater than 1.

10. The resonator according to claim 1 or 9, characterized in that: The total thickness of the dielectric film layer and the piezoelectric material layer is less than λ, where λ=2p, and p represents the spatial period of the metal electrodes on the metal electrode layer.

11. The resonator according to claim 1, characterized in that The material of the dielectric film layer includes single crystal quartz, and the material of the piezoelectric film layer includes one of LiTaO3 and LiNbO3.

12. The resonator according to claim 11, characterized in that The Euler angles of the dielectric thin film layer are (ω1, μ1, φ1), wherein ω1 ranges from -5° to 5°, μ1 ranges from -85° to -5°, and φ1 ranges from 85° to 95° or -95° to -85°; The material of the piezoelectric film layer includes LiTaO3, and the Euler angle of the piezoelectric film layer is (ω2, μ2, φ2), wherein ω2 ranges from -5° to 5°, μ2 ranges from -75° to -25°, and φ2 ranges from -5° to 5° or 175° to 185°; The material of the piezoelectric film layer includes LiNbO3, and the Euler angle of the piezoelectric film layer is (ω3, μ3, φ3), wherein ω3 ranges from -5° to 5°, μ3 ranges from -110° to -25°, and φ3 ranges from -5° to 5° or 175° to 185°.

13. A resonator, characterized in that: The resonator comprises: substrate; A quartz thin film layer is disposed on the substrate; A piezoelectric film layer is disposed on the quartz film layer; A metal electrode layer, disposed on the piezoelectric film layer; The acoustic waves of the resonator when working include surface acoustic waves and bulk waves, the quartz film layer constrains the surface acoustic waves within the surface range of the piezoelectric film layer, the bulk waves propagate in at least one of the substrate, the quartz film layer and the piezoelectric film layer, and the thickness H of the piezoelectric film layer and / or the quartz film layer satisfies the following relationship: Among them, α is the ratio of phase shift to π, f r represents the resonant frequency of the surface acoustic wave, if H represents the thickness of the piezoelectric film layer, then θ represents the angle between the propagation direction of the body wave in the piezoelectric film layer and the surface of the piezoelectric film layer, V B (θ) represents the propagation speed of the bulk wave in the piezoelectric thin film layer. If H represents the thickness of the quartz thin film layer, then θ represents the angle between the propagation direction of the bulk wave in the quartz thin film layer and the surface of the quartz thin film layer, V B (θ) represents the propagation speed of the body wave in the quartz thin film layer, and η is a constant greater than 1.

14. The resonator according to claim 13, characterized in that The thickness H of the piezoelectric film layer and / or the quartz film layer satisfies the following relationship:

15. The resonator according to claim 14, characterized in that The thickness of the piezoelectric film layer is greater than or equal to 0.1λ and less than or equal to 0.5λ; the thickness of the quartz film layer is greater than or equal to 0.1λ and less than or equal to 0.5λ, wherein λ=2p, and p represents the spatial period of the metal electrodes on the metal electrode layer.

16. The resonator according to claim 13 or 14, characterized in that The total thickness of the dielectric film layer and the piezoelectric material layer is less than λ, where λ=2p, and p represents the spatial period of the metal electrodes on the metal electrode layer.

17. The resonator according to claim 13 or 14, characterized in that: The total thickness of the dielectric film layer and the piezoelectric material layer is less than 0.6λ.

18. The resonator according to claim 13, characterized in that The material used for the substrate includes single crystal silicon.

19. The resonator according to claim 18, characterized in that The propagation direction of the surface acoustic wave is consistent with the single crystal silicon substrate. <110> The directions within a first preset angle offset range of the crystal orientation family are parallel.

20. The resonator according to claim 18, characterized in that The Euler angle of the substrate is (45°±5°, 0±5°, 0±5°), (0±5°, 90°±5°, 45°±5°), (±5°, -54.7±5°, -135°±5°) or (0±5°, 54.7°±5°, 45°±5°).

21. A resonator, characterized in that: The resonator comprises: Silicon substrate; A quartz thin film layer is disposed on the silicon substrate; A piezoelectric film layer is disposed on the quartz film layer; A metal electrode layer, disposed on the piezoelectric film layer; The acoustic waves of the resonator when working include surface acoustic waves and bulk waves. The quartz film layer constrains the surface acoustic waves within the surface range of the piezoelectric film layer. The bulk waves propagate in at least one of the silicon substrate, the quartz film layer and the piezoelectric film layer. The propagation direction of the surface acoustic waves is parallel to the direction of the silicon substrate. <110> The directions within a first preset angle offset range of the crystal orientation family are parallel.

22. The resonator according to claim 21, characterized in that The first preset angle offset range includes 170° to 180° or 0° to 10°.

23. The resonator according to claim 22, characterized in that The cut surface of the silicon substrate includes a cut surface within a second preset angle offset range of the normal direction of the {001} crystal plane family, or a cut surface within a second preset angle offset range of the normal direction of the {110} crystal plane family, or a cut surface within a second preset angle offset range of the normal direction of the {111} crystal plane family.

24. The resonator according to claim 23, characterized in that The second preset angle offset range includes 0° to 5° or 175° to 180°.

25. The resonator according to claim 21, characterized in that The material of the silicon substrate includes single crystal silicon, and the Euler angle of the silicon substrate is (45°±5°, 0±5°, 0±5°), (0±5°, 90°±5°, 45°±5°), (±5°, -54.7±5°, -135°±5°), or (0±5°, 54.7°±5°, 45°±5°).

26. The resonator according to claim 21, characterized in that The total thickness of the quartz film layer and the piezoelectric material layer is less than λ, where λ=2p, and p represents the spatial period of the metal electrodes on the metal electrode layer.

27. The resonator according to claim 21, characterized in that: The total thickness of the quartz thin film layer and the piezoelectric material layer is less than 0.6λ.

28. The resonator according to claim 21, characterized in that The material of the quartz film layer includes single crystal quartz, and the material of the piezoelectric film layer includes one of LiTaO3 and LiNbO3.

29. The resonator according to claim 28, characterized in that The Euler angles of the quartz thin film layer are (ω1, μ1, φ1), wherein ω1 ranges from -5° to 5°, μ1 ranges from -85° to -5°, and φ1 ranges from 85° to 95° or -95° to -85°; The material of the piezoelectric film layer includes LiTaO3, and the Euler angle of the piezoelectric film layer is (ω2, μ2, φ2), wherein ω2 ranges from -5° to 5°, μ2 ranges from -75° to -25°, and φ2 ranges from -5° to 5° or 175° to 185°; The material of the piezoelectric film layer includes LiNbO3, and the Euler angle of the piezoelectric film layer is (ω3, μ3, φ3), wherein ω3 ranges from -5° to 5°, μ3 ranges from -110° to -25°, and φ3 ranges from -5° to 5° or 175° to 185°.

30. A resonator, characterized in that: The resonator comprises: substrate; A dielectric thin film layer is disposed on the substrate; A piezoelectric film layer is disposed on the dielectric film layer; A metal electrode layer, disposed on the piezoelectric film layer; Among them, the sound waves of the resonator when working include surface acoustic waves and body waves, the dielectric film layer constrains the surface acoustic waves within the surface range of the piezoelectric film layer, and the body waves propagate in at least one of the substrate, the dielectric film layer and the piezoelectric film layer. The material used for the substrate can cause the body waves with a target frequency to leak in the substrate, and the target frequency is greater than the resonant frequency of the surface acoustic wave.

31. The resonator according to claim 30, characterized in that The material used for the substrate includes single crystal silicon.

32. The resonator according to claim 31, characterized in that The propagation direction of the surface acoustic wave is consistent with the single crystal silicon substrate. <110> The directions within a first preset angle offset range of the crystal orientation family are parallel.

33. The resonator according to claim 30, characterized in that The thickness H of the piezoelectric film layer and / or the dielectric film layer satisfies the following relationship: Among them, α is the ratio of phase shift to π, f r represents the resonant frequency of the surface acoustic wave, if H represents the thickness of the piezoelectric film layer, then θ represents the angle between the propagation direction of the body wave in the piezoelectric film layer and the surface of the piezoelectric film layer, V B (θ) represents the propagation speed of the bulk wave in the piezoelectric film layer. If H represents the thickness of the dielectric film layer, then θ represents the angle between the propagation direction of the bulk wave in the dielectric film layer and the surface of the dielectric film layer. V B (θ) represents the propagation speed of the body wave in the dielectric thin film layer, and η is a constant greater than 1.

34. The resonator according to claim 30 or 33, characterized in that The total thickness of the dielectric film layer and the piezoelectric material layer is less than λ, where λ=2p, and p represents the spatial period of the metal electrodes on the metal electrode layer.

35. The resonator according to claim 30 or 33, characterized in that The total thickness of the dielectric film layer and the piezoelectric material layer is less than 0.6λ.

36. The resonator according to claim 30, characterized in that The material of the dielectric film layer includes single crystal quartz, and the material of the piezoelectric film layer includes one of LiTaO3 and LiNbO3.

37. The resonator according to claim 30, characterized in that The speed V2 at which the bulk wave propagates in the dielectric film layer is greater than the speed at which the bulk wave propagates in the piezoelectric film layer or greater than the speed at which the surface acoustic wave propagates in the piezoelectric film layer, and the speed at which the bulk wave propagates in the substrate is less than or equal to 1.5V2.

38. A surface acoustic wave filter, characterized in that: The surface acoustic wave filter comprises the resonator according to any one of claims 1-37.

39. A radio frequency front-end module, characterized in that: The RF front-end module includes the filter as described in claim 38.

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