A laterally excited film bulk acoustic wave device and filter

Abstract

The application provides a transversely excited film bulk acoustic wave device and filter, the transversely excited film bulk acoustic wave device comprising a supporting substrate, the supporting substrate comprising an acoustic wave reflection structure; a piezoelectric layer, the piezoelectric layer being arranged on a first surface of the supporting substrate; an interdigital transducer, the interdigital transducer comprising electrode fingers; the interdigital transducer being arranged on a surface of the piezoelectric layer away from the supporting substrate; a first groove array being arranged on the first surface of the supporting substrate, and a second groove array being arranged on the surface of the piezoelectric layer away from the supporting substrate; along an acoustic wave propagation direction, the first groove array is arranged on both sides of a vertical projection of the interdigital transducer on the first surface of the supporting substrate; along the acoustic wave propagation direction, the second groove array is arranged on both sides of the interdigital transducer, so that the out-of-band rejection capability of the transversely excited film bulk acoustic wave device can be improved and the insertion loss can be reduced.

Description

Technical Field

[0001] This invention relates to the field of radio frequency technology, and in particular to a transversely excited thin-film bulk acoustic wave device and filter. Background Technology

[0002] With the surge in demand for higher frequency bands and wider bandwidths in 5G / 6G communications, IoT, and RF front-end systems, laterally excited thin-film bulk acoustic wave (TFT-OS) devices have great potential to become core components of RF filters due to their high operating frequencies (up to 10 GHz and above), large bandwidth, and compatibility with CMOS processes. However, existing TFT-OS devices suffer from low out-of-band rejection and high insertion loss. Summary of the Invention

[0003] The present invention provides a transversely excited thin-film bulk acoustic wave device and filter to improve the out-of-band rejection capability and reduce the insertion loss of the transversely excited thin-film bulk acoustic wave device.

[0004] According to one aspect of the present invention, a transversely excited thin-film bulk acoustic wave device is provided, characterized in that it comprises: A support substrate, the support substrate including an acoustic wave reflecting structure; A piezoelectric layer is disposed on a first surface of the support substrate; An interdigital transducer, the interdigital transducer comprising electrode fingers; The interdigital transducer is disposed on the surface of the piezoelectric layer away from the supporting substrate; A first groove array is provided on the first surface of the support substrate, and / or a second groove array is provided on the surface of the piezoelectric layer away from the support substrate. Along the direction of sound wave propagation, the first groove array is disposed on both sides of the vertical projection of the interdigital transducer onto the first surface of the support substrate. Along the direction of sound wave propagation, a second groove array is disposed on both sides of the interdigital transducer.

[0005] Optionally, the ratio of the number of grooves in the first groove array to the number of electrode fingers is greater than or equal to a first preset value, wherein the first preset value is greater than or equal to 15%; The ratio of the number of grooves in the second groove array to the number of electrode fingers is greater than or equal to a first preset value.

[0006] Optionally, the interdigital transducer includes a first busbar and a second busbar, and the electrode fingers include a first electrode finger and a second electrode finger; The first electrode finger and the second electrode finger are arranged alternately along the direction of sound wave propagation, and the first busbar and the second busbar are arranged opposite each other along the extension direction of the electrode fingers; The first electrode finger is connected to the first bus bar, and the second electrode finger is connected to the second bus bar.

[0007] Optionally, the acoustic wave reflection structure is an air cavity that extends through the supporting substrate along a direction perpendicular to the first surface.

[0008] Optionally, the length of the grooves in the first groove array along the electrode finger extension direction is greater than or equal to the spacing between the first busbar and the second busbar; The length of the grooves in the second groove array along the electrode finger extension direction is greater than or equal to the spacing between the first busbar and the second busbar.

[0009] Optionally, the second groove array includes a conductive material that is flush with the surface of the piezoelectric layer away from the supporting substrate.

[0010] Optionally, the conductive material is the same as the material of the electrode.

[0011] Optionally, the piezoelectric layer is made of lithium niobate, and the supporting substrate is made of silicon.

[0012] Optionally, the supporting substrate includes a substrate and a Bragg reflection structure disposed on the side of the substrate adjacent to the piezoelectric layer, wherein the Bragg reflection structure is the acoustic wave reflection structure.

[0013] According to another aspect of the present invention, a laterally excited thin-film bulk acoustic wave filter is provided, the laterally excited thin-film bulk acoustic wave filter comprising the laterally excited thin-film bulk acoustic wave device described in any embodiment.

[0014] The laterally excited thin-film bulk acoustic wave device of this invention includes a support substrate, the support substrate including an acoustic wave reflecting structure; a piezoelectric layer disposed on a first surface of the support substrate; and an interdigital transducer including electrode fingers. The interdigital transducer is disposed on the surface of the piezoelectric layer away from the support substrate. By providing a first groove array on the first surface of the support substrate, along the acoustic wave propagation direction, the first groove array is disposed on both sides of the vertical projection of the interdigital transducer onto the first surface of the support substrate. Leaked acoustic waves can be reflected to the effective resonant region, thereby suppressing stray modes near the resonant point and improving the quality factor at the anti-resonant point, further improving the out-of-band rejection capability and reducing the insertion loss of the laterally excited thin-film bulk acoustic wave device. By providing a second groove array on the surface of the piezoelectric layer away from the support substrate, along the acoustic wave propagation direction, the second groove array is disposed on both sides of the interdigital transducer, so that the second groove array can effectively reflect the elastic waves propagating to the support substrate, suppressing stray modes near the resonant point and improving the quality factor at the anti-resonant point, improving the out-of-band rejection capability and reducing the insertion loss of the laterally excited thin-film bulk acoustic wave device.

[0015] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a top view of a transversely excited thin-film bulk acoustic wave device provided in an embodiment of the present invention; Figure 2 yes Figure 1 Cross-sectional view of a transversely excited thin-film bulk acoustic device along section line AA1. Figure 3 This is a top view of another transversely excited thin-film bulk acoustic wave device provided in an embodiment of the present invention; Figure 4 yes Figure 3 Cross-sectional view of a transversely excited thin-film bulk acoustic device along section line BB1. Figure 5 yes Figure 3 Another cross-sectional view of the transversely excited thin-film bulk acoustic device along BB1; Figure 6 This is a side view of the laterally excited thin-film bulk acoustic wave device of the comparative embodiment; Figure 7 This is an admittance-frequency curve of a transversely excited thin-film bulk acoustic wave device according to a comparative embodiment; Figure 8 This is a comparison diagram of admittance-frequency curves of a transversely excited thin-film bulk acoustic wave device provided in an embodiment of the present invention; Figure 9 This is a graph showing the change in admittance value at the anti-resonance frequency point of the transversely excited thin-film bulk acoustic device provided in this embodiment as a function of the ratio of the number of grooves to the number of electrode fingers. Figure 10 This is a top view of another transversely excited thin-film bulk acoustic wave device provided in an embodiment of the present invention; Figure 11 yes Figure 10 Cross-sectional view of a transversely excited thin-film bulk acoustic device along section line CC1. Figure 12 yes Figure 10 Another cross-sectional view of a transversely excited thin-film bulk acoustic device along the CC1 section line. Figure 13 yes Figure 1 Another cross-sectional view of the transversely excited thin-film bulk acoustic device along section line AA1. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0019] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0020] This invention provides a transversely excited thin-film bulk acoustic wave device. Figure 1This is a top view of a transversely excited thin-film bulk acoustic wave device provided in an embodiment of the present invention. Figure 2 for Figure 1 A cross-sectional view of a transversely excited thin-film bulk acoustic wave device along section line AA1. Figure 3 This is a top view of another laterally excited thin-film bulk acoustic wave device provided in an embodiment of the present invention. Figure 4 yes Figure 3 Cross-sectional view of a transversely excited thin-film bulk acoustic wave device along section line BB1; Reference Figures 1-4 The transversely excited thin-film bulk acoustic wave device includes: Support substrate 10, the support substrate 10 includes an acoustic wave reflecting structure 11; A piezoelectric layer 20 is disposed on the first surface 12 of the support substrate 10; Interdigital transducer 30, interdigital transducer 30 includes electrode fingers 31; Interdigital transducers 30 are disposed on the surface of the piezoelectric layer 20 away from the support substrate 10; A first groove array 40 is provided on the first surface 12 of the support substrate 10, and / or a second groove array 50 is provided on the surface of the piezoelectric layer 20 away from the support substrate 10. Along the direction of sound wave propagation, the first groove array 40 is disposed on both sides of the interdigital transducer 30 on the vertical projection of the first surface 12 of the support substrate 10. Along the direction of sound wave propagation, the second groove array 50 is disposed on both sides of the interdigital transducer 30.

[0021] Specifically, the support substrate 10 is made of a material with high sound velocity, and the support substrate 101 is a high-sound-velocity component. The piezoelectric layer 20 is a thin single-crystal layer made of a piezoelectric material. Piezoelectric materials may include lithium niobate, lithium tantalate, gallium nitride, aluminum nitride, or zinc oxide, etc. Parallel to the coordinate system... x The axis is oriented in the direction of sound wave propagation and is parallel to the coordinate system. y The direction of the axis is the extension direction of electrode finger 31, parallel to the coordinate system. z The axis is oriented along the height of the laterally excited thin-film bulk acoustic wave device. All grooves in the first groove array 40 have the same shape, and the spacing between adjacent grooves in the first groove array 40 is equal. All grooves in the second groove array 50 have the same shape, and the spacing between adjacent grooves in the second groove array 50 is equal. The sound wave excited by the laterally excited thin-film bulk acoustic wave device is a Lamb wave, i.e., a plate wave; therefore, the interdigital transducer 30 does not have reflectors on either side of the sound wave propagation direction. The sound wave reflection structure 11 can be an air cavity or a Bragg reflection structure.

[0022] A first groove array 40 is provided on the first surface 12 of the support substrate 10. Along the direction of acoustic wave propagation, the first groove array 40 is disposed on both sides of the interdigital transducer 30 in the vertical projection of the first surface 12 of the support substrate 10. This can reflect the leaked acoustic waves to the effective resonant region, thereby suppressing stray modes near the resonant point and improving the quality factor at the anti-resonant point, further improving the out-of-band rejection capability and reducing the insertion loss of the laterally excited thin-film bulk acoustic wave device. A second groove array 50 is provided on the surface of the piezoelectric layer 20 away from the support substrate 10. The second groove array 50 is disposed on both sides of the interdigital transducer 30 and can form a wavelength impedance transformation. This can reflect the leaked acoustic waves to the effective resonant region, so that the second groove array 50 can effectively reflect the elastic waves propagating to the support substrate 10, suppressing stray modes near the resonant point and improving the quality factor at the anti-resonant point, thereby improving the out-of-band rejection capability and reducing the insertion loss of the laterally excited thin-film bulk acoustic wave device.

[0023] Figure 5 for Figure 3 Another cross-sectional view of the transversely excited thin-film bulk acoustic device along BB1. Figure 6 This is a side view of the laterally excited thin-film bulk acoustic wave device of the comparative embodiment. Figure 7 For the admittance-frequency curve of the laterally excited thin-film bulk acoustic wave device in the comparative embodiment, refer to... Figures 4-7 In the comparative embodiment, except that the first groove array 40 is not provided on the first surface 12 of the support substrate 10, and the second groove array 50 is not provided on the surface of the piezoelectric layer 20 away from the support substrate 10, the rest of the configuration is the same as in this embodiment. Figure 7 It can be seen that the resonant frequency of the transversely excited thin-film bulk acoustic device in the comparative embodiment is 4625MHz, the anti-resonant frequency is 5300MHz, and the electromechanical coupling coefficient is about 31.4%. There are many spurious modes near the resonant frequency, which seriously affect the performance of the device. Figure 8 This is a comparison diagram of admittance-frequency curves for a laterally excited thin-film bulk acoustic wave device provided in an embodiment of the present invention. Figure 8 The red curve represents the admittance-frequency curve of the laterally excited thin-film bulk acoustic wave device in this embodiment, while the black curve represents the admittance-frequency curve of the laterally excited thin-film bulk acoustic wave device in the comparative embodiment. Figure 8It can be seen that the resonant frequency of the laterally excited thin-film bulk acoustic wave device in this embodiment is 4585MHz, the anti-resonant frequency is 5285MHz, and the electromechanical coupling coefficient is approximately 32.7%. Compared with the laterally excited thin-film bulk acoustic wave device of the comparative embodiment, the spurious modes near the resonant frequency are basically suppressed, and the admittance value at the anti-resonant frequency is smaller, while the quality factor at the anti-resonant point is higher. Admittance is a physical quantity describing the response of a circuit element to alternating current and voltage. Admittance Y is equal to the ratio of conductance G to susceptance B, i.e., Y = G + jB, where j is the imaginary unit. In this embodiment, the admittance (dB) can be expressed by the formula Y(dB) = 20 × log 10 |Y| is obtained. In acoustic devices, stray modes refer to all undesirable additional vibrational modes that interfere with the performance of the main mode, in addition to the main operating mode intended by the device design. The resonant frequency of the resonator is set to... f s The anti-resonant frequency is set to f p The electromechanical coupling coefficient can be obtained from the formula K 2 = π 2 / 4×( f p - f s ) / f p To obtain.

[0024] The laterally excited thin-film bulk acoustic wave device of this invention includes a support substrate 10, which includes an acoustic wave reflecting structure 11; a piezoelectric layer 20 disposed on a first surface 12 of the support substrate 10; and an interdigital transducer 30, which includes electrode fingers 31. The interdigital transducer 30 is disposed on the surface of the piezoelectric layer 20 away from the support substrate 10. By providing a first groove array 40 on the first surface 12 of the support substrate 10, the first groove array 40 is disposed on both sides of the vertical projection of the interdigital transducer 30 onto the first surface 12 of the support substrate 10 along the acoustic wave propagation direction. This can reflect leaked acoustic waves to the effective resonant region, thereby suppressing stray modes near the resonant point and improving the quality factor at the anti-resonant point, further improving the out-of-band suppression capability and reducing the insertion loss of the laterally excited thin-film bulk acoustic wave device. By providing a second groove array 50 on the surface of the piezoelectric layer 20 away from the support substrate 10, and by providing the second groove array 50 on both sides of the interdigital transducer 30 along the direction of acoustic wave propagation, the second groove array 50 can effectively reflect the elastic waves propagating to the support substrate 10, thereby suppressing stray modes near the resonant point and improving the quality factor at the anti-resonant point, improving the out-of-band suppression capability of the transversely excited thin-film bulk acoustic wave device and reducing insertion loss.

[0025] Figure 9 The graph showing the admittance at the anti-resonant frequency of the laterally excited thin-film bulk acoustic device provided in this embodiment as a function of the ratio of the number of grooves to the number of electrode fingers is shown in the reference graph. Figure 2 and Figure 9 Optionally, the ratio of the number of grooves in the first groove array 40 to the number of electrode fingers 31 is greater than or equal to a first preset value, wherein the first preset value is greater than or equal to 15%; The ratio of the number of grooves in the second groove array 50 to the number of electrode fingers 31 is greater than or equal to a first preset value.

[0026] Specifically, by Figure 9 It can be seen that when the ratio γ of the number of grooves in the first groove array 40 to the number of electrode fingers 31 is greater than or equal to 15%, the admittance value at the anti-resonant frequency is smaller, and the quality factor at the anti-resonant point is higher. When the ratio γ of the number of grooves in the second groove array 50 to the number of electrode fingers 31 is greater than or equal to 15%, the admittance value at the anti-resonant frequency is smaller, and the quality factor at the anti-resonant point is higher.

[0027] Optionally, the interdigital transducer 30 includes a first busbar 33 and a second busbar 34, and the electrode fingers 31 include a first electrode finger 311 and a second electrode finger 312. The first electrode finger 311 and the second electrode finger 312 are arranged alternately along the direction of sound wave propagation, and the first bus bar 33 and the second bus bar 34 are arranged opposite each other along the extension direction of the electrode finger 31. The first electrode finger 311 is connected to the first busbar 33, and the second electrode finger 312 is connected to the second busbar 34.

[0028] For details, please refer to [link / reference]. Figure 1 The interdigital transducer 30 utilizes the piezoelectric effect to achieve the interconversion between electrical signals and surface acoustic waves, completing the bidirectional coupling of electroacoustic energy. The first electrode finger 311 and the second electrode finger 312 are arranged alternately along the direction of sound wave propagation (i.e., along the X direction). The first busbar 33 uniformly transmits electrical signals to the first electrode finger 311, and the second busbar 34 uniformly transmits electrical signals to the second electrode finger 312. The first busbar 33 and the second busbar 34 are positioned opposite each other along the extension direction of the electrode finger 31 (i.e., along the Y direction).

[0029] Optionally, the acoustic wave reflection structure 11 is an air cavity 111, which extends through the support substrate 10 along a direction perpendicular to the first surface 12.

[0030] For details, please refer to [link / reference]. Figure 2By setting the acoustic wave reflection structure 11 as an air cavity 111, acoustic boundary conditions can be formed by the air cavity 111 to reflect and confine the propagating acoustic waves, thereby limiting the acoustic waves to the inside of the piezoelectric layer 20, reducing the leakage loss of acoustic waves, and thus improving the quality factor of the transversely excited thin film acoustic wave device.

[0031] Optionally, the length of the grooves in the first groove array 40 along the extension direction of the electrode finger 31 is greater than or equal to the spacing between the first busbar 33 and the second busbar 34. The length of the grooves in the second groove array 50 along the extension direction of the electrode finger 31 is greater than or equal to the spacing between the first busbar 33 and the second busbar 34.

[0032] Specifically, the length of the grooves in the first groove array 40 along the extension direction of the electrode finger 31 is too small, resulting in excessive sound wave leakage and increased sound wave loss. By setting the length of the grooves in the second groove array 50 along the extension direction of the electrode finger 31 to be greater than or equal to the distance between the first busbar 33 and the second busbar 34, the loss of sound waves can be suppressed, and the sound wave leakage loss can be reduced.

[0033] The length of the grooves in the second groove array 50 along the extension direction of the electrode finger 31 is too small, resulting in excessive sound wave leakage and increased sound wave loss. By setting the length of the grooves in the second groove array 50 along the extension direction of the electrode finger 31 to be greater than or equal to the distance between the first busbar 33 and the second busbar 34, the loss of sound waves can be suppressed and the sound wave leakage loss can be reduced.

[0034] Figure 10 This is a top view of another laterally excited thin-film bulk acoustic wave device provided in an embodiment of the present invention. Figure 11 for Figure 10 A cross-sectional view of a transversely excited thin-film bulk acoustic device along section CC1. Figure 12 for Figure 10 Another cross-sectional view of the transversely excited thin-film bulk acoustic device along the CC1 section line, see reference. Figures 10-12 Optionally, the second groove array 50 includes a conductive material 60, which is flush with the surface of the piezoelectric layer 20 away from the support substrate 10.

[0035] Specifically, by filling the second groove array 50 with conductive material 60, a structure with high and low acoustic impedance can be constructed, which can form an acoustic impedance contrast and reflect the leaked sound waves to the effective resonant region. This allows the second groove array 50 to effectively reflect the elastic waves propagating to the support substrate 10, suppressing stray modes near the resonant point and improving the quality factor at the anti-resonant point, thereby improving the out-of-band suppression capability and reducing the insertion loss of the transversely excited thin-film bulk acoustic wave device.

[0036] Optionally, the conductive material 60 is the same as the material of the electrode finger 31.

[0037] Specifically, the conductive material 60 is a metal, which can be aluminum, aluminum-copper alloy, copper, gold, platinum, molybdenum, tungsten, silver or nickel, etc. By setting the conductive material 60 to be the same as the material of the electrode finger 31, the process difficulty can be reduced.

[0038] Optionally, the piezoelectric layer 20 is made of lithium niobate, and the support substrate 10 is made of silicon.

[0039] Specifically, by using lithium niobate as the material for the piezoelectric layer 20, the piezoelectric coefficient and electromechanical coupling coefficient of the piezoelectric layer 20 are high, and the acoustic wave loss is low, thereby improving the bandwidth and quality factor of the laterally excited thin-film bulk acoustic wave device. By using silicon as the material for the support substrate 10, the support substrate 10 has low acoustic wave transmission loss and good insulation performance and mechanical stability. At the same time, it is compatible with the fabrication process of the laterally excited thin-film bulk acoustic wave device, which can ensure the acoustic performance and operational reliability of the laterally excited thin-film bulk acoustic wave device.

[0040] Figure 13 for Figure 1 Another cross-sectional view of the transversely excited thin-film bulk acoustic device along section AA1, see reference. Figure 1 and Figure 13 Optionally, the support substrate 10 includes a substrate 70 and a Bragg reflection structure 112 disposed on the side of the substrate 70 adjacent to the piezoelectric layer 20. The Bragg reflection structure 112 is an acoustic wave reflection structure 11.

[0041] Specifically, the Bragg reflector structure 112 is composed of alternating layers of high acoustic impedance and low acoustic impedance. The acoustic Bragg reflector reflects acoustic wave energy back to the piezoelectric layer 20, preventing acoustic waves from leaking towards the supporting substrate, thus achieving effective confinement of acoustic waves without the need for back cavity etching. This structure not only enhances the mechanical stability of the device but also simplifies the wafer-level packaging process and improves manufacturing yield.

[0042] This invention provides a laterally excited thin-film bulk acoustic wave filter, wherein the laterally excited thin-film bulk acoustic wave resonator includes any embodiment of the laterally excited thin-film bulk acoustic wave device.

[0043] The transversely excited thin-film bulk acoustic filter of this embodiment belongs to the same inventive concept as the transversely excited thin-film bulk acoustic device provided in any embodiment of the present invention, and has corresponding beneficial effects. For technical details not detailed in this embodiment, please refer to the transversely excited thin-film bulk acoustic device described in any embodiment of the present invention.

[0044] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0045] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A transversely excited thin-film bulk acoustic wave device, characterized in that, include: A support substrate, the support substrate including an acoustic wave reflecting structure; A piezoelectric layer is disposed on a first surface of the support substrate; An interdigital transducer, the interdigital transducer comprising electrode fingers; The interdigital transducer is disposed on the surface of the piezoelectric layer away from the supporting substrate; A first groove array is provided on the first surface of the support substrate, and / or a second groove array is provided on the surface of the piezoelectric layer away from the support substrate. Along the direction of sound wave propagation, the first groove array is disposed on both sides of the vertical projection of the interdigital transducer onto the first surface of the support substrate. Along the direction of sound wave propagation, a second groove array is disposed on both sides of the interdigital transducer.

2. The transversely excited thin-film bulk acoustic wave device according to claim 1, characterized in that: The ratio of the number of grooves in the first groove array to the number of electrode fingers is greater than or equal to a first preset value, wherein the first preset value is greater than or equal to 15%; The ratio of the number of grooves in the second groove array to the number of electrode fingers is greater than or equal to a first preset value.

3. The transversely excited thin-film bulk acoustic wave device according to claim 1, characterized in that: The interdigital transducer includes a first busbar and a second busbar, and the electrode fingers include a first electrode finger and a second electrode finger; The first electrode finger and the second electrode finger are arranged alternately along the direction of sound wave propagation, and the first busbar and the second busbar are arranged opposite each other along the extension direction of the electrode fingers; The first electrode finger is connected to the first busbar, and the second electrode finger is connected to the second busbar.

4. The transversely excited thin-film bulk acoustic wave device according to claim 1, characterized in that: The acoustic wave reflection structure is an air cavity that extends through the supporting substrate along a direction perpendicular to the first surface.

5. The transversely excited thin-film bulk acoustic wave device according to claim 3, characterized in that: The length of the grooves in the first groove array along the electrode finger extension direction is greater than or equal to the spacing between the first busbar and the second busbar; The length of the grooves in the second groove array along the electrode finger extension direction is greater than or equal to the spacing between the first busbar and the second busbar.

6. The transversely excited thin-film bulk acoustic wave device according to claim 1, characterized in that: The second groove array includes a conductive material that is flush with the surface of the piezoelectric layer away from the supporting substrate.

7. The transversely excited thin-film bulk acoustic wave device according to claim 6, characterized in that: The conductive material is the same as the material of the electrode.

8. The transversely excited thin-film bulk acoustic wave device according to claim 1, characterized in that: The piezoelectric layer is made of lithium niobate, and the supporting substrate is made of silicon.

9. The transversely excited thin-film bulk acoustic wave device according to claim 1, characterized in that: The supporting substrate includes a substrate and a Bragg reflection structure disposed on the side of the substrate adjacent to the piezoelectric layer, wherein the Bragg reflection structure is the acoustic wave reflection structure.

10. A transversely excited thin-film bulk acoustic wave filter, characterized in that, The device includes the transversely excited thin-film bulk acoustic wave device according to any one of claims 1-9.

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