Acoustic resonator with transversely excited shear mode

Abstract

The present invention relates to an acoustic resonator for a transversely excited shear mode, comprising: an acoustic mirror comprising at least one first acoustic reflection layer and at least one second acoustic reflection layer, the acoustic impedance of each first acoustic reflection layer being less than the acoustic impedance of each second acoustic reflection layer; a piezoelectric layer disposed on the acoustic mirror, the piezoelectric layer comprising single-crystalline lithium niobate and / or single-crystalline lithium tantalate; an electrode unit disposed on the piezoelectric layer for forming an electric field; and a transverse reflector disposed on the piezoelectric layer, comprising a first reflector located on a first side of the electrode unit and a second reflector located on a second side of the electrode unit, the first and second sides being opposite sides, the transverse reflector being configured to laterally reflect acoustic waves. The present invention can achieve a high electromechanical coupling coefficient and a high Q value at frequencies above 3 GHz.

Description

Technical Field

[0001] The present application relates to the technical field of resonators, and in particular to an acoustic resonator with a transversely excited shear mode. Background Art

[0002] RF acoustic resonators are small, microstructures used to synthesize filtering functions or serve as frequency sources. Due to their smaller size and higher quality factor (Q), acoustic resonators are replacing other types of resonators used in mobile phones, small base stations, and IoT devices. They can achieve low loss (low power consumption), high rejection, a high signal-to-noise ratio, and even ultra-thin packaging.

[0003] With the release of new communication standards (i.e., the fifth generation of mobile networks), it is necessary to extend the operating range of resonators to higher frequencies while maintaining high electromechanical coupling coefficients and high Q values. Summary of the Invention

[0004] Based on this, it is necessary to provide an acoustic resonator that can excite the transverse shear mode with high electromechanical coupling coefficient and high Q value at frequencies above 3 GHz.

[0005] An acoustic resonator of a transversely excited shear mode comprises: an acoustic mirror comprising at least one first acoustic reflection layer and at least one second acoustic reflection layer, the acoustic impedance of each first acoustic reflection layer being smaller than the acoustic impedance of each second acoustic reflection layer; a piezoelectric layer disposed on the acoustic mirror, the piezoelectric layer comprising lithium niobate of a single crystal material and / or lithium tantalate of a single crystal material; an electrode unit disposed on the piezoelectric layer and configured to form an electric field; and a transverse reflector disposed on the piezoelectric layer, comprising a first reflector located on a first side of the electrode unit and a second reflector located on a second side of the electrode unit, the first side and the second side being opposite sides, the transverse reflector configured to laterally reflect sound waves.

[0006] In one embodiment, the electrode unit is configured to form an electric field that is mainly parallel to the piezoelectric layer and to generate a shear mode mechanical wave throughout the thickness of the piezoelectric layer.

[0007] In one embodiment, the farther the first acoustic reflection layer is from the piezoelectric layer, the thicker the first acoustic reflection layer is; and the farther the second acoustic reflection layer is from the piezoelectric layer, the thicker the second acoustic reflection layer is.

[0008] In one embodiment, the acoustic mirror includes three first acoustic reflection layers and two second acoustic reflection layers, and the first acoustic reflection layers and the second acoustic reflection layers are alternately arranged in the acoustic mirror.

[0009] In one embodiment, the material of the first sound reflection layer includes at least one of silicon dioxide, aluminum, benzocyclobutene, polyimide and spin glass, and the material of the second sound reflection layer includes at least one of molybdenum, tungsten, titanium, platinum, aluminum nitride, tungsten oxide and silicon nitride.

[0010] In one embodiment, the electrode unit includes a first common electrode, a second common electrode, a plurality of first interdigitated electrodes and a plurality of second interdigitated electrodes, each of the first interdigitated electrodes is electrically connected to the first common electrode, each of the second interdigitated electrodes is electrically connected to the second common electrode, and each of the first interdigitated electrodes is insulated from each of the second interdigitated electrodes, the first common electrode is used to access the input voltage, and the second common electrode is used to be grounded.

[0011] In one embodiment, the connection direction between the lateral reflectors on both sides of the electrode unit is the propagation direction of the sound wave; the two side edges of each first acoustic reflection layer and each second acoustic reflection layer of the acoustic mirror in the first direction are aligned, and the first direction is perpendicular to the connection direction in the plane, and the plane is perpendicular to the height direction of the resonator; the first end of each first interdigitated electrode is connected to the first common electrode, the first end of each second interdigitated electrode is connected to the second common electrode, the orthographic projection of the edge of the first end of each first interdigitated electrode on the acoustic mirror is aligned with the first side edge of the acoustic mirror in the first direction, and the orthographic projection of the edge of the first end of each second interdigitated electrode on the acoustic mirror is aligned with the second side edge of the acoustic mirror in the first direction.

[0012] In one embodiment, the first reflector and the second reflector each include at least one electrode strip, the distance between the center of the electrode strip closest to the electrode unit in the first reflector and the center of the interdigitated electrode at the first side edge of the electrode unit is 1 / 8 to 2 wavelengths of the sound wave, and the distance between the center of the electrode strip closest to the electrode unit in the second reflector and the center of the interdigitated electrode at the second side edge of the electrode unit is 1 / 8 to 2 wavelengths of the sound wave.

[0013] In one embodiment, it also includes a first metal part on the first common electrode and a second metal part on the second common electrode, the thickness of the first metal part and the second metal part is greater than the thickness of the electrode unit, and the first metal part and the second metal part are used for acoustic reflection in a first direction, and the first direction is perpendicular to the propagation direction of the sound wave.

[0014] In one embodiment, the electrode unit and the transverse reflector are made of the same material, which is metal and / or alloy.

[0015] In one embodiment, there is a first acoustic reflective layer closer to the piezoelectric layer than all the second acoustic reflective layers.

[0016] The transversely excited shear mode acoustic resonator generates an electric field through electrode elements and reflects sound waves laterally through transverse reflectors, thereby exciting a transverse shear vibration mode. Because the piezoelectric layer utilizes single-crystal lithium niobate or lithium tantalate, it exhibits a high electromechanical coupling coefficient and high Q value at frequencies above 3 GHz. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 is a top view of a partial structure of an acoustic resonator for transversely excited shear mode in one embodiment;

[0019] Figure 2 It is along Figure 1 Sectional view along line A-A';

[0020] Figure 3 Schematic diagram of the propagation direction of the electric field and mechanical waves in the piezoelectric layer;

[0021] Figure 4 is a schematic diagram of the thickness of each reflective layer of a reflector in one embodiment;

[0022] Figure 5 is a schematic structural diagram of a first reflector in one embodiment;

[0023] Figure 6 It is along Figure 1 Cross-sectional view along line BB';

[0024] Figure 7 1 is a mark of the thickness of each membrane layer of an acoustic resonator in a transversely excited shear mode in one embodiment;

[0025] Figure 8 It is the dimension mark of the main structure of the electrode unit and the transverse reflector in one embodiment;

[0026] Figure 9 The figure shows the simulation results of the characteristic admittance of an acoustic resonator in a transversely excited shear mode according to an embodiment. DETAILED DESCRIPTION

[0027] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings provide embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0029] It should be understood that when an element or layer is referred to as being "on," "adjacent to," "connected to," or "coupled to" another element or layer, it can be directly on, adjacent to, connected to, or coupled to the other element or layer, or there can be intervening elements or layers. Conversely, when an element is referred to as being "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" another element or layer, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, doping types, and / or portions, these elements, components, regions, layers, doping types, and / or portions should not be limited by these terms. These terms are merely used to distinguish one element, component, region, layer, doping type, or portion from another element, component, region, layer, doping type, or portion. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer, doping type or portion discussed below may be represented as a second element, component, region, layer or portion; for example, the first doping type may be referred to as the second doping type, and similarly, the second doping type may be referred to as the first doping type; the first doping type and the second doping type are different doping types, for example, the first doping type may be P-type and the second doping type may be N-type, or the first doping type may be N-type and the second doping type may be P-type.

[0030] Spatially relative terms such as "under," "beneath," "beneath," "under," "above," "above," etc., may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that in addition to the orientations shown in the figures, spatially relative terms also include different orientations of the device in use and operation. For example, if the device in the drawings is turned over, the element or feature described as "under" or "beneath" or "beneath" the other elements will be oriented as "above" the other elements or features. Thus, the exemplary terms "under" and "under" can include both upper and lower orientations. In addition, the device can also include alternative orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0031] As used herein, the singular forms "a," "an," and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include," "comprising," "having," and the like specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, in this specification, the term "and / or" includes any and all combinations of the relevant listed items.

[0032] Embodiments of the invention are described herein with reference to cross-sectional views which are schematic illustrations of idealized embodiments (and intermediate structures) of the invention, such that variations in the shapes shown due to, for example, manufacturing techniques and / or tolerances are anticipated. Accordingly, embodiments of the invention should not be limited to the specific shapes of the regions shown herein, but rather include deviations in shapes due to, for example, manufacturing techniques. For example, an implanted region shown as a rectangle typically has rounded or curved features and / or an implant concentration gradient at its edges rather than a binary change from an implanted region to a non-implanted region. Similarly, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation occurs. Accordingly, the regions shown in the figures are schematic in nature, their shapes do not represent the actual shape of the region of the device, and do not limit the scope of the invention.

[0033] Bulk acoustic wave (BAW) and surface acoustic wave (SAW) resonators are the most commonly used devices for synthesizing filters and oscillators between 0.6 GHz and 3 GHz. These acoustic devices are commercially successful and are widely used in mobile phone front-end modules or as discrete components in radio front-ends. Existing BAW and SAW devices can exhibit Q values ​​exceeding 1000 and electromechanical coupling coefficients of approximately 7%-10% at frequencies below 3 GHz. However, extending their frequency operating range above 3 GHz encounters several technical uncertainties and physical limitations. The new 5G standard requires an electromechanical coupling coefficient exceeding 10%, a requirement that BAW and SAW devices cannot achieve without changing the constituent materials or operating mode. Similarly, material losses pose a fundamental limitation to the maximum achievable Q value of traditional BAW and SAW devices above 3 GHz.

[0034] In summary, the market needs new devices that can have high electromechanical coupling and high quality factor at frequencies above 3 GHz.

[0035] This application aims to develop a novel wafer-level mechanical / acoustic resonator that exhibits high Q and high electromechanical coupling coefficient at frequencies above 3 GHz. This resonator will support the synthesis of high-performance passband filters to meet the emerging requirements of the 5G communication standard and future upgrades.

[0036] Figure 1 FIG. 1 is a top view of a partial structure of an acoustic resonator for a transversely excited shear mode in one embodiment. Figure 2 It is along Figure 1 Sectional view along line A-A'. Figure 1 and Figure 2 The acoustic resonator of the transverse excitation shear mode includes an acoustic mirror 120, a piezoelectric layer 130, an electrode unit and a transverse reflector. Figure 1 Mainly for illustrating the shapes of the electrode units and the transverse reflectors in the corresponding embodiments, other structures on the piezoelectric layer 130 are omitted.

[0037] The electrode unit is provided on the piezoelectric layer 130 for forming an electric field. The electrode unit may include interdigitated electrodes. Figure 1 and Figure 2 In the embodiment shown, the electrode unit includes a group of first interdigital electrodes 141 and a group of second interdigital electrodes 143. The first interdigital electrodes 141 and the second interdigital electrodes 143 are oriented in a first direction ( Figure 1The electrodes 141 and 143 extend in the Y direction (in the Y direction) and are therefore parallel to each other. Each first interdigital electrode 141 is insulated from each second interdigital electrode 143. The first interdigital electrodes 141 are used to receive input voltage, while the second interdigital electrodes 143 are used for grounding. The electrode unit also includes a first common electrode 142 and a second common electrode 144. One end of each first interdigital electrode 141 is connected to the first common electrode 142, and one end of each second interdigital electrode 143 is connected to the second common electrode 144. Common electrodes are also called bus bars.

[0038] The transverse reflector is also provided on the piezoelectric layer 130 and can be provided on the same layer as the electrode unit, including a first side ( Figure 1 The first reflector 152 on the left side of the electrode unit and the second reflector 152 on the second side of the electrode unit Figure 1 The lateral reflector is insulated from the electrode unit and is used to reflect sound waves laterally.

[0039] The piezoelectric layer 130 is disposed on the acoustic mirror 120. The piezoelectric layer 130 includes single-crystal lithium niobate and / or single-crystal lithium tantalate.

[0040] The acoustic mirror 120 includes at least one first acoustic reflection layer and at least one second acoustic reflection layer, and the acoustic impedance of each first acoustic reflection layer is smaller than the acoustic impedance of each second acoustic reflection layer. In one embodiment of the present application, the layer closest to the piezoelectric layer 130 in the acoustic mirror 120 should be the first acoustic reflection layer, that is, there is a first acoustic reflection layer that is closer to the piezoelectric layer 130 than all the second acoustic reflection layers. Figure 2 In the illustrated embodiment, the acoustic mirror 120 includes three first sound reflection layers (i.e., the first sound reflection layer 121, the first sound reflection layer 123, and the first sound reflection layer 125) and two second sound reflection layers (i.e., the second sound reflection layer 122 and the second sound reflection layer 124), and the first sound reflection layers and the second sound reflection layers are alternately arranged.

[0041] The transversely excited shear mode acoustic resonator generates an electric field through the electrode unit and reflects the acoustic wave laterally through the transverse reflector, thereby exciting a transverse shear vibration mode. Because the piezoelectric layer 130 is made of single-crystal lithium niobate or lithium tantalate, it can achieve a high electromechanical coupling coefficient and a high Q value at frequencies above 3 GHz.

[0042] See also Figure 3In the figure, the large arrow indicates the direction of the electric field, and the small arrow indicates the propagation direction of the mechanical wave in the shear vibration mode. The electric field is primarily parallel to the piezoelectric layer 130 and is used to generate shear mode mechanical waves throughout the thickness of the piezoelectric layer 130. The combination of single-crystal lithium niobate / lithium tantalate with the electrode unit structure and transverse reflector structure of the present application can produce an optimized shear vibration mode. This shear vibration mode has a higher acoustic wave velocity and can achieve higher frequencies than traditional commercial filters while maintaining key device dimensions (such as the interdigital pitch).

[0043] In one embodiment of the present application, the electrode unit is made of the same material as the transverse reflector, namely, metal and / or alloy. In one embodiment of the present application, the electrode unit can be made of aluminum (Al), copper (Cu), aluminum copper (AlCu), aluminum silicon copper (AlSiCu), molybdenum (Mo), tungsten (W), silver (Ag), or any other conductive metal.

[0044] exist Figure 2 In the illustrated embodiment, the transversely excited shear mode acoustic resonator further includes a carrier wafer 110 . The acoustic mirror 120 is disposed on the carrier wafer 110 .

[0045] In one embodiment of the present application, a bonding auxiliary layer is further provided between the carrier wafer 110 and the acoustic mirror 120 to assist in bonding between the carrier wafer 110 and the acoustic mirror 120. In one embodiment of the present application, the bonding auxiliary layer is a thin layer of silicon dioxide.

[0046] In one embodiment of the present application, each first acoustic reflection layer is made of a low acoustic impedance material, and each second acoustic reflection layer is made of a high acoustic impedance material. The low acoustic impedance material may be at least one of silicon dioxide, aluminum, benzocyclobutene (BCB), polyimide, and spin-on glass, and the high acoustic impedance material may be at least one of molybdenum, tungsten, titanium, platinum, aluminum nitride, aluminum oxide, tungsten oxide, and silicon nitride. It is understood that in other embodiments, the low acoustic impedance material and the high acoustic impedance material may also be other material combinations having a larger impedance ratio.

[0047] The first acoustic reflection layer and the second acoustic reflection layer of the acoustic mirror 120 may have equal or unequal thicknesses. In one embodiment of the present application, the farther the first acoustic reflection layer is from the piezoelectric layer 130, the thicker it is; and the farther the second acoustic reflection layer is from the piezoelectric layer 130, the thicker it is. This design can achieve a higher Q value. Figure 4 ,exist Figure 4In the illustrated embodiment, the thickness Tl1 of the first sound reflection layer 121 is less than the thickness Tl2 of the first sound reflection layer 123, less than the thickness Tl3 of the first sound reflection layer 125, and the thickness Th1 of the second reflection layer 122 is less than the thickness Th2 of the second reflection layer 124. It is understood that in other embodiments, the thickness relationship between the first sound reflection layer and the second sound reflection layer can also be set according to other rules, such as Tl1=Tl2=Tl3, Th1=Th2; or Tl1>Tl2>Tl3, Th1>Th2; or Tl1 <Tl2,Tl3<Tl2,Th1<Th2。

[0048] Figure 1 Also shown is the position of the acoustic mirror 120 from a top-down perspective. Figure 1 The X direction in the figure represents the direction of propagation of the sound waves. The edges of each first acoustic reflection layer and each second acoustic reflection layer of the acoustic mirror 120 in the Y direction are aligned. The orthographic projection of the edge of each first interdigital electrode 141 away from the first common electrode 142 on the acoustic mirror 120 is aligned with the first side edge of the acoustic mirror 120 in the first Y direction. The orthographic projection of the edge of each second interdigital electrode 143 away from the first common electrode 142 on the acoustic mirror 120 is aligned with the second side edge of the acoustic mirror 120 in the Y direction.

[0049] like Figure 5 As shown, the electrode strips of the transverse reflector can be disconnected from each other or as shown in FIG. Figure 1 The electrode strips of the transverse reflector can be arranged parallel to the fingers of the electrode unit.

[0050] Figure 6 It is along Figure 1 Cross-sectional view along line BB'. In this embodiment, the area of ​​the acoustic mirror 120 is smaller than the area of ​​the piezoelectric layer 130 and the carrier wafer 110, so a filling layer is provided around the acoustic mirror 120. In one embodiment of the present application, the filling layer can be made of one or more of silicon dioxide, molybdenum, tungsten, tungsten oxide, or silicon nitride. In one embodiment of the present application, the material of the filling layer is the same as that of each first acoustic reflection layer, thereby improving the quality factor of the acoustic resonator.

[0051] exist Figure 6 In the embodiment shown, the acoustic resonator of the transverse excitation shear mode further includes a first metal member 145 provided on the first common electrode 141 and a second metal member 147 provided on the second common electrode 143. The thickness of the first metal member 145 and the second metal member 147 is greater than the thickness of the electrode unit. The first metal member 145 and the second metal member 147 are used to Figure 1 Acoustic reflection is performed in the Y direction.

[0052] In one embodiment of the present application, the distance W between the center of the electrode strip closest to the electrode unit in the first reflector 152 and the center of the interdigital electrode at the first side edge of the electrode unit is g (See Figure 8 ) is 1 / 8 to 2 wavelengths of the sound wave; the distance between the center of the electrode strip closest to the electrode unit in the second reflector 154 and the center of the interdigitated electrode at the second side edge of the electrode unit is 1 / 8 to 2 wavelengths of the sound wave.

[0053] The vibration frequency of the mechanical wave of the shear vibration mode formed in the piezoelectric layer 130 is related to the thickness of each membrane layer and the spacing between adjacent interdigital electrodes in the electrode unit. The stress is mainly confined to the area without metal coverage between the first interdigital electrode 141 and the second interdigital electrode 143. Figure 7 and Figure 8 The important film thickness / spacing of the resonator are marked in the figure.

[0054] exist Figure 7 In the illustrated embodiment, the transversely excited shear mode acoustic resonator further includes a passivation layer 160. The passivation layer 160 is disposed on the piezoelectric layer 130 and covers the first interdigital electrodes 141 and the second interdigital electrodes 143. The passivation layer 160 can reduce the frequency temperature coefficient of the resonator and passivate the metal electrodes.

[0055] Figure 9 The simulation results of the characteristic admittance of the acoustic resonator in the transverse excitation shear mode of an embodiment are shown in FIG. Where (b) is a local curve of (a), k t is the electromechanical coupling coefficient. Eigenfrequency simulations were used to obtain the optimized stacked reflector thickness for a resonant frequency of 4.8 GHz. The same eigenfrequency analysis was used to determine the optimal in-plane reflector position and the relative position of the reflector stack with respect to the interdigital electrodes.

[0056] Throughout this specification, references to terms such as "some embodiments," "other embodiments," and "desired embodiments" indicate that a particular feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. Although these terms are used interchangeably throughout this specification, they do not necessarily refer to the same embodiment or example.

[0057] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features of the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0058] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. An acoustic resonator with a transversely excited shear mode, characterized in that include: An acoustic mirror comprising at least one first acoustic reflection layer and at least one second acoustic reflection layer, wherein the acoustic impedance of each of the first acoustic reflection layers is smaller than the acoustic impedance of each of the second acoustic reflection layers; a piezoelectric layer, provided on the acoustic mirror, wherein the piezoelectric layer comprises lithium niobate of a single crystal material and / or lithium tantalate of a single crystal material; an electrode unit, provided on the piezoelectric layer, for forming an electric field; a transverse reflector, provided on the piezoelectric layer, comprising a first reflector located on a first side of the electrode unit and a second reflector located on a second side of the electrode unit, the first side and the second side being opposite sides, the transverse reflector being used to reflect the sound wave laterally; The electrode unit includes a first common electrode, a second common electrode, a plurality of first interdigital electrodes, and a plurality of second interdigital electrodes, each of the first interdigital electrodes is electrically connected to the first common electrode, each of the second interdigital electrodes is electrically connected to the second common electrode, and each of the first interdigital electrodes is insulated from each of the second interdigital electrodes, the first common electrode is used to receive an input voltage, and the second common electrode is used for grounding; The two side edges of each first acoustic reflection layer and each second acoustic reflection layer of the acoustic mirror in the first direction are aligned, the first end of each first interdigital electrode is connected to the first common electrode, the first end of each second interdigital electrode is connected to the second common electrode, the orthographic projection of the edge of the first end of each first interdigital electrode on the acoustic mirror is aligned with the first side edge of the acoustic mirror in the first direction, and the orthographic projection of the edge of the first end of each second interdigital electrode on the acoustic mirror is aligned with the second side edge of the acoustic mirror in the first direction; The acoustic resonator of the transversely excited shear mode also includes a first metal part arranged on the first common electrode and a second metal part on the second common electrode, the thickness of the first metal part and the second metal part is greater than the thickness of the electrode unit, the first metal part and the second metal part are used for acoustic reflection in a first direction, the first direction is perpendicular to the propagation direction of the sound wave, the connection direction between the transverse reflectors on both sides of the electrode unit is the propagation direction of the sound wave, the first direction is perpendicular to the connection direction in the plane, and the plane is perpendicular to the height direction of the resonator.

2. The acoustic resonator of the transversely excited shear mode according to claim 1, characterized in that The electrode unit is used to form an electric field mainly parallel to the piezoelectric layer and to generate a shear mode mechanical wave throughout the thickness of the piezoelectric layer.

3. The acoustic resonator of the transversely excited shear mode according to claim 1, characterized in that The farther the first acoustic reflection layer is from the piezoelectric layer, the thicker the thickness is; and the farther the second acoustic reflection layer is from the piezoelectric layer, the thicker the thickness is.

4. The acoustic resonator of the transversely excited shear mode according to claim 1, characterized in that The acoustic mirror includes three first acoustic reflection layers and two second acoustic reflection layers, and the first acoustic reflection layers and the second acoustic reflection layers are alternately arranged in the acoustic mirror.

5. The transversely excited shear mode acoustic resonator according to claim 1, characterized in that: The material of the first sound reflection layer includes at least one of silicon dioxide, aluminum, benzocyclobutene, polyimide and spin glass, and the material of the second sound reflection layer includes at least one of molybdenum, tungsten, titanium, platinum, aluminum nitride, tungsten oxide and silicon nitride.

6. The acoustic resonator of the transversely excited shear mode according to claim 1, characterized in that The first reflector and the second reflector each include at least one electrode strip, and the distance between the center of the electrode strip closest to the electrode unit in the first reflector and the center of the interdigitated electrode at the first side edge of the electrode unit is 1 / 8 to 2 wavelengths of the sound wave, and the distance between the center of the electrode strip closest to the electrode unit in the second reflector and the center of the interdigitated electrode at the second side edge of the electrode unit is 1 / 8 to 2 wavelengths of the sound wave.

7. The transversely excited shear mode acoustic resonator according to claim 1, characterized in that: The electrode unit and the transverse reflector are made of the same material, which is metal and / or alloy.

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