Acoustic wave resonator and manufacturing method therefor, and electronic device

Abstract

The present application relates to the field of resonators, and discloses an acoustic wave resonator and a manufacturing method therefor, and an electronic device. The acoustic wave resonator comprises: a substrate; a piezoelectric layer arranged on the surface of the substrate; an acoustic velocity compensation layer arranged on the surface of the side of the piezoelectric layer facing away from the substrate, and comprising a plurality of grooves sequentially arranged in a first direction, the first direction being parallel to the plane where the piezoelectric layer is located; and interdigital electrodes formed, by means of the acoustic velocity compensation layer having the grooves, on the surface of the side of the piezoelectric layer facing away from the substrate, and comprising a plurality of fingers arranged in one-to-one correspondence with the grooves, the fingers being in electrical contact with the piezoelectric layer by means of the corresponding grooves. The technical solution of the present application can increase the frequency without reducing the size of the interdigital electrodes, and the resistance of the interdigital electrodes will not increase, which can avoid reduction in quality factors of the acoustic wave resonator, and effectively improve the performance of the acoustic wave resonator, thereby achieving a high-quality acoustic wave resonator.

Description

An acoustic resonator, its fabrication method, and electronic equipment.

[0001] This application claims priority to Chinese Patent Application No. 202411875936.9, filed on December 18, 2024, entitled "An Acoustic Resonator and Its Fabrication Method and Electronic Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of resonator technology, and in particular to an acoustic resonator, its fabrication method, and electronic equipment. Background Technology

[0003] Currently, acoustic resonators are widely used in the communications industry due to their small size, large bandwidth, and high quality factor (Q value). However, with the advancement of communication technology, frequency bands are becoming increasingly congested, making the exploration of higher-frequency wireless communication technologies particularly important. Therefore, research on higher-frequency acoustic resonators is especially crucial.

[0004] Taking interdigitated acoustic resonators as an example, in practical applications, as the frequency increases, the size of the interdigitated electrodes decreases, leading to an increase in electrode resistance. This increased resistance significantly reduces the quality factor, thus degrading the performance of the acoustic resonator. Summary of the Invention

[0005] In view of the above problems, this application provides an acoustic resonator, its fabrication method, and an electronic device thereof, in order to improve the performance of the acoustic resonator. The specific solution is as follows:

[0006] The first aspect of this application provides an acoustic resonator, comprising:

[0007] Substrate;

[0008] A piezoelectric layer disposed on the surface of a substrate;

[0009] A sound velocity compensation layer is disposed on the surface of the piezoelectric layer away from the substrate. The sound velocity compensation layer has multiple grooves arranged sequentially along a first direction. The first direction is parallel to the plane where the piezoelectric layer is located.

[0010] The interdigitated electrode is formed on the surface of the piezoelectric layer away from the substrate based on a sound velocity compensation layer with grooves; the interdigitated electrode includes a plurality of fingers that are arranged one-to-one with the grooves; the fingers make electrical contact with the piezoelectric layer based on the corresponding grooves.

[0011] Optionally, in the above-mentioned acoustic resonator, the sound velocity of the sound velocity compensation layer is not less than the sound velocity of the piezoelectric layer and the interdigitated electrodes.

[0012] Optionally, in the above-mentioned acoustic resonator, the thickness of the sound velocity compensation layer is h1, and the material density of the sound velocity compensation layer is ρ1.

[0013] The thickness of the interdigitated electrode is h2, and the material density of the interdigitated electrode is ρ2;

[0014] Wherein, ρ1·h1=A·ρ2·h2; where A is a set constant.

[0015] Optionally, in the above acoustic resonator, 2≤A≤10.

[0016] Optionally, in the above-mentioned acoustic resonator, the thickness of the sound velocity compensation layer is h1, and the thickness of the interdigitated electrodes is h2.

[0017] in,

[0018] Optionally, in the above-mentioned acoustic resonator, the width of the groove remains unchanged in the direction from the substrate to the piezoelectric layer; or, the width of the groove gradually increases.

[0019] Optionally, in the above-mentioned acoustic resonator, the thickness of the sound velocity compensation layer ranges from 10 nm to 10000 nm;

[0020] The thickness of the finger strip ranges from 10 nm to 10,000 nm;

[0021] The thickness of the piezoelectric layer ranges from 10 nm to 10,000 nm.

[0022] Optionally, in the above-mentioned acoustic resonator, the Young's modulus of the sound velocity compensation layer ranges from 5 × 10⁻⁶. 10 Pa ~ 1×10 12 Pa;

[0023] The density of the sound velocity compensation layer ranges from 2000 kg / m³. 3 ~6000kg / m 3 .

[0024] A second aspect of this application provides a method for fabricating an acoustic resonator, comprising:

[0025] Provide a substrate;

[0026] A piezoelectric layer is formed on the surface of the substrate;

[0027] A sound velocity compensation layer is formed on the side of the piezoelectric layer facing away from the substrate. The sound velocity compensation layer has a plurality of grooves arranged sequentially along a first direction. The first direction is parallel to the plane where the piezoelectric layer is located.

[0028] Based on the sound velocity compensation layer with grooves, interdigitated electrodes are formed on the surface of the piezoelectric layer away from the substrate. The interdigitated electrodes include multiple fingers that are arranged one-to-one with the grooves. The fingers make electrical contact with the piezoelectric layer based on the corresponding grooves.

[0029] A third aspect of this application provides a filter comprising an acoustic resonator provided in any of the above-described manner.

[0030] A fourth aspect of this application provides an electronic device including an acoustic resonator provided in any of the above-described ways.

[0031] By employing the above technical solution, the acoustic resonator, its fabrication method, and electronic device provided in this application have a sound velocity compensation layer formed on the surface of a piezoelectric layer. This sound velocity compensation layer has multiple grooves arranged sequentially along a first direction. Based on the grooved sound velocity compensation layer, interdigitated electrodes can be formed on the surface of the piezoelectric layer. Each interdigitated electrode has multiple fingers corresponding to one groove, and each groove can be used to set one interdigitated electrode. The fingers are in electrical contact with the piezoelectric layer based on the corresponding groove. Since the interdigitated electrodes are fabricated based on the grooved sound velocity compensation layer, the sound velocity compensation layer, the interdigitated electrodes, and the piezoelectric layer can be constructed as a single waveguide. This allows the interdigitated electrodes to participate more effectively in the propagation of sound waves, reducing energy scattering caused by scattering. Therefore, the technical solution of this application can increase the frequency without reducing the size of the interdigitated electrodes, and the resistance of the interdigitated electrodes will not increase. This avoids a decrease in the quality factor of the acoustic resonator, effectively improving its performance and achieving a high-quality acoustic resonator. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0033] The structures, proportions, sizes, etc., shown in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and purposes that this application can produce, should still fall within the scope of the technical content disclosed in this application.

[0034] Figure 1 is a schematic diagram of the structure of an acoustic resonator provided in an embodiment of this application;

[0035] Figure 2 is a schematic diagram of another acoustic resonator provided in an embodiment of this application;

[0036] Figure 3 is a schematic diagram of another acoustic resonator provided in an embodiment of this application;

[0037] Figure 4 is a schematic diagram of another acoustic resonator provided in an embodiment of this application;

[0038] Figure 5 is a schematic diagram of another acoustic resonator provided in an embodiment of this application;

[0039] Figure 6 is a schematic diagram of another acoustic resonator provided in an embodiment of this application;

[0040] Figure 7 is a top view of the electrode pattern in an acoustic resonator provided in an embodiment of this application;

[0041] Figure 8 is a cross-sectional schematic diagram of an acoustic resonator operating at a frequency of 6.2 GHz provided in an embodiment of this application;

[0042] Figure 9 shows the simulated admittance curve of an acoustic resonator operating at a frequency of 6.2 GHz;

[0043] Figure 10 is a cross-sectional schematic diagram of an acoustic resonator operating at a frequency of 4.6 GHz provided in an embodiment of this application;

[0044] Figure 11 shows the simulated admittance curve of an acoustic resonator operating at a frequency of 4.6 GHz;

[0045] Figure 12 shows the simulated admittance curve of an acoustic resonator operating at a frequency of 6.9 GHz;

[0046] Figure 13 shows the simulated admittance curve of an acoustic resonator operating at a frequency of 7.8 GHz;

[0047] Figure 14 shows the simulated admittance curve of an acoustic resonator operating at a frequency of 8.4 GHz;

[0048] Figure 15 shows the simulated admittance curve of an acoustic resonator operating at a frequency of 7.6 GHz.

[0049] Figure 16 shows the simulated admittance curve of an acoustic resonator operating at a frequency of 8.6 GHz;

[0050] Figure 17 is a cross-sectional view of another acoustic resonator provided in an embodiment of this application;

[0051] Figure 18 is a cross-sectional view of another acoustic resonator provided in an embodiment of this application;

[0052] Figure 19 is a schematic flowchart of an acoustic resonator fabrication method provided in an embodiment of this application.

[0053] Reference numerals: 1-substrate; 2-piezoelectric layer; 3-interdigital electrode; 30-finger strip; 31-first busbar; 32-second busbar; 4-sound velocity compensation layer; 41-groove; 5-isolation gap; 6-reflective grid. Detailed Implementation

[0054] The embodiments of this application will now be clearly and completely described with reference to the accompanying drawings. Those skilled in the art will recognize that, with technological advancements and the emergence of new scenarios, the technical solutions provided in the embodiments of this application are equally applicable to similar technical problems.

[0055] Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The terminology used in the embodiments of this application is only used to explain the specific embodiments of this application, and is not intended to limit this application.

[0056] With the rapid development of communication technology, the demand for new frequency bands is increasing, especially under the leadership of fifth-generation mobile communication technology (5G). Communication systems not only need to support a wider range of frequency bands but also meet higher performance requirements. 5G networks introduce several new frequency bands, such as millimeter-wave bands, whose bandwidth far exceeds that of previous generations, providing higher data transmission rates and lower latency. These new frequency bands pose greater challenges and requirements to communication systems, including higher frequency accuracy, lower signal interference, and greater bandwidth support.

[0057] Against this backdrop, the quality factor of acoustic resonators has become a key factor in improving system performance. A high quality factor in acoustic resonators can effectively improve filter performance, reduce insertion loss, enhance out-of-band rejection, and improve signal stability and clarity. Furthermore, the quality factor of acoustic resonators directly affects the selectivity and bandwidth characteristics of filters, thus impacting the overall performance of the RF system. To meet the high-frequency demands of new frequency bands and ensure the efficient operation of communication systems, designing and manufacturing acoustic resonators with higher quality factors has become particularly important. This not only helps improve filter performance but also enhances the overall stability and reliability of the system.

[0058] In traditional interdigitated acoustic resonators, as the frequency increases, the interdigital electrodes shrink, leading to increased resistance. Higher resistance significantly degrades the quality factor, resulting in a decrease in the overall quality of the acoustic resonator. Therefore, improving the quality factor of acoustic resonators while increasing the frequency is a problem that urgently needs to be solved by those skilled in the art.

[0059] To address the aforementioned problems, embodiments of this application provide an acoustic resonator, comprising:

[0060] Substrate;

[0061] A piezoelectric layer disposed on the surface of a substrate;

[0062] A sound velocity compensation layer is disposed on the surface of the piezoelectric layer away from the substrate. The sound velocity compensation layer has multiple grooves arranged sequentially along a first direction. The first direction is parallel to the plane where the piezoelectric layer is located.

[0063] The interdigitated electrode is formed on the surface of the piezoelectric layer away from the substrate based on a sound velocity compensation layer with grooves; the interdigitated electrode includes a plurality of fingers that are arranged one-to-one with the grooves; the fingers make electrical contact with the piezoelectric layer based on the corresponding grooves.

[0064] In the acoustic resonator provided in this embodiment, the sound velocity compensation layer, interdigitated electrodes, and piezoelectric layer can be configured as an integral waveguide. The interdigitated electrodes can participate more effectively in the propagation of sound waves, reducing energy dissipation caused by scattering. Therefore, while increasing the frequency, the acoustic resonator does not need to reduce the size of the interdigitated electrodes, nor does it increase the resistance of the interdigitated electrodes. This avoids a decrease in the quality factor of the acoustic resonator, effectively improving its performance and achieving a high-quality acoustic resonator.

[0065] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0066] Referring to Figure 1, which is a schematic diagram of an acoustic resonator provided in an embodiment of this application, the acoustic resonator includes:

[0067] Substrate 1;

[0068] A piezoelectric layer 2 disposed on the surface of substrate 1;

[0069] A sound velocity compensation layer 4 is disposed on the surface of the piezoelectric layer 2 away from the substrate 1. The sound velocity compensation layer 4 has a plurality of grooves 41 arranged sequentially along a first direction x. The first direction x is parallel to the plane where the piezoelectric layer 2 is located.

[0070] Interdigitated electrodes 3 are formed on the surface of the piezoelectric layer 2 away from the substrate 1 based on a sound velocity compensation layer 4 with grooves 41. Interdigitated electrodes 3 include a plurality of fingers 30 that are arranged one-to-one with the grooves 41. The fingers 30 make electrical contact with the piezoelectric layer 2 based on the corresponding grooves 41.

[0071] In the acoustic resonator provided in this application embodiment, since the interdigital electrode 3 is fabricated based on the sound velocity compensation layer 4 with groove 41, the sound velocity compensation layer 4, the interdigital electrode 3, and the piezoelectric layer 2 can be constructed into an integral waveguide. Based on this integral waveguide, the interdigital electrode 3 can participate more effectively in the propagation of sound waves, reducing energy scattering caused by scattering. Therefore, the technical solution of this application can increase the frequency without reducing the size of the interdigital electrode 3, and the resistance of the interdigital electrode 3 will not increase. This avoids the reduction of the quality factor of the acoustic resonator, effectively improves the performance of the acoustic resonator, and realizes a high-quality acoustic resonator.

[0072] In one embodiment of this application, the sound velocity of the sound velocity compensation layer 4 is set to be not less than the sound velocity of the piezoelectric layer 2 and the interdigital electrode 3, that is, the sound velocity of the sound velocity compensation layer 4 is greater than or equal to the sound velocity of the piezoelectric layer 2 and greater than or equal to the sound velocity of the interdigital electrode 3.

[0073] If the sound velocity of the sound velocity compensation layer 4 is less than the sound velocity of the piezoelectric layer 2 and the interdigital electrode 3, it will result in the inability to effectively adjust the propagation speed of the sound wave in the acoustic resonator. In this embodiment, the sound velocity of the sound velocity compensation layer 4 is set to be no less than the sound velocity of the piezoelectric layer 2 and the interdigital electrode 3. This allows the overall waveguide constructed by the sound velocity compensation layer 4, the interdigital electrode 3, and the piezoelectric layer 2 to better adjust the propagation speed of the sound wave in the acoustic resonator, thereby effectively improving the performance of the acoustic resonator.

[0074] The shear mode sound velocity of the metal material used to prepare the interdigitated electrode 3 is set as V1, and the shear mode sound velocity of the piezoelectric material used to prepare the piezoelectric layer 2 is set as V2. The sound velocity of the sound velocity compensation layer 4 is set as V0.

[0075] If V1 > V2, then V0 ≥ V2; if V1 < V2, then V0 ≥ V1. In this case, V0 is not less than the smaller of V1 and V2. In this case, V0 can be between V1 and V2, or V0 can be greater than both V1 and V2.

[0076] When V0 is not less than the smaller of V1 and V2, if V0 is located between V1 and V2, the electromechanical coupling coefficient k of the acoustic resonator can be made smaller. 2 Larger. k 2 The larger the value of , the larger the bandwidth of the acoustic resonator and the better the passband rectangularity. This method can effectively optimize the bandwidth performance of the acoustic resonator.

[0077] When V0 is not less than the smaller of V1 and V2, if V0 is greater than V1 and greater than V2, the operating frequency of the acoustic resonator can be greatly increased. This method can improve the high-frequency performance of the acoustic resonator.

[0078] The thickness and material density of the sound velocity compensation layer 4 are matched with the thickness and material density of the interdigitated electrode 3 to enable the acoustic resonator to have a higher operating frequency.

[0079] In this embodiment of the application, in order to facilitate the fabrication of the interdigital electrode 3, the thickness of each finger strip 30 in the interdigital electrode 3 can be set to be the same.

[0080] The thickness of the sound velocity compensation layer 4 can be set to h1, and the material density of the sound velocity compensation layer 4 can be set to ρ1; the thickness of the interdigitated electrode 3 can be set to h2, and the material density of the interdigitated electrode can be set to ρ2. The thickness and material density of the sound velocity compensation layer 4 and the thickness and material density of the interdigitated electrode 3 satisfy the matching relationship shown in the following equation (1). ρ1·h1=A·ρ2·h2 (1)

[0081] Where A is a set constant.

[0082] It is readily known that the sound velocity compensation layer 4 is an insulating material, and the interdigitated electrode 3 is a conductive material. For the interdigitated electrode 3 with a given material and thickness, based on the above equation (1), it can be known that the material density ρ1 and thickness h1 of the sound velocity compensation layer 4 need to have an inverse relationship, and the inverse ratio coefficient is A, so that the sound velocity compensation layer 4 can better optimize the performance of the acoustic resonator, better adjust the sound wave propagation speed, better adjust the bandwidth of the acoustic resonator, and better improve the acoustic performance.

[0083] For the sound velocity compensation layer 4 and the interdigitated electrode 3 with determined materials, the material densities of the two are fixed values, that is, ρ1 and ρ2 are constants that can be determined. At this time, by adjusting the thickness of the sound velocity compensation layer 4 and the interdigitated electrode 3, that is, by adjusting the values ​​of h1 and h2, the thickness and material density of the sound velocity compensation layer 4 and the thickness and material density of the interdigitated electrode 3 can satisfy the matching relationship shown in the following formula (1), so that the acoustic resonator has a higher operating frequency.

[0084] Based on the above formula (1), in this embodiment of the application, the thickness values ​​of the sound velocity compensation layer 4 and the interdigital electrode 3 can be preset, that is, the values ​​of h1 and h2 can be given in advance. Under the given h1 and h2, the sound velocity compensation layer 4 and the interdigital electrode 3 with material density that satisfies the above matching relationship can be selected. By adjusting ρ1 and / or ρ2, the thickness and material density of the sound velocity compensation layer 4 and the thickness and material density of the interdigital electrode 3 can satisfy the matching relationship shown in the following formula (1), so that the acoustic resonator has a higher operating frequency.

[0085] As can be seen from the above description, in the embodiments of this application, at least one of h1, h2, ρ1 and ρ2 can be adjusted so that the thickness and material density of the sound velocity compensation layer 4 and the thickness and material density of the interdigitated electrode 3 satisfy the matching relationship shown in the following formula (1), so that the acoustic resonator has a higher operating frequency.

[0086] Optionally, 2 ≤ A ≤ 10. The inventors have found that when 2 ≤ A ≤ 10, the acoustic resonator can have a higher operating frequency. If the value of A is less than 2 or greater than 10, the operating frequency of the acoustic resonator will be lower.

[0087] In one embodiment of this application, as shown in FIG1, h1 < h2 can be set.

[0088] In the acoustic resonator provided in this application embodiment, the thickness h1 of the interdigital electrode 3 and the depth of the groove 41 can be adjusted according to usage requirements, and the thickness h1 of the interdigital electrode 3 and the depth of the groove 41 can be adaptively increased to optimize the performance of the acoustic resonator.

[0089] Referring to Figure 2, which is a schematic diagram of another acoustic resonator provided in an embodiment of this application, in which h1 = h2.

[0090] Referring to Figure 3, which is a schematic diagram of another acoustic resonator provided in an embodiment of this application, in which h1 > h2.

[0091] In this embodiment, the thicknesses of the sound velocity compensation layer 4 and the interdigitated electrodes 3 satisfy the following relationship:

[0092] When the thickness of the sound velocity compensation layer 4 and the interdigitated electrode 3 satisfies the above formula (2), the acoustic resonator can have a larger operating frequency.

[0093] like A value less than 0.1 or greater than 10 will cause a significant decrease in the operating frequency of the acoustic resonator, greatly affecting its high-frequency performance. Therefore, the thicknesses of the sound velocity compensation layer 4 and the interdigital electrodes 3 can be further set to satisfy the following relationship:

[0094] When the thickness of the sound velocity compensation layer 4 and the interdigitated electrode 3 satisfies the above formula (3), the acoustic resonator can have a larger operating frequency.

[0095] When the sound velocity compensation layer 4 is made of silicon dioxide and its thickness ratio to that of the finger strip 30 is 1:4, that is... The acoustic resonator is used to operate at a frequency of 6.2 GHz.

[0096] When the sound velocity compensation layer 4 is made of silicon oxide and its thickness ratio to that of the interdigitated electrode 3 is 11:4, that is... The acoustic resonator is used to operate at a frequency of 4.6 GHz.

[0097] When the sound velocity compensation layer 4 is made of silicon oxide and its thickness ratio to that of the interdigitated electrode 3 is 5:2, that is... The acoustic resonator is used to operate at a frequency of 6.9 GHz.

[0098] When the sound velocity compensation layer 4 is made of silicon nitride and its thickness ratio to that of the interdigitated electrode 3 is 2:1, that is... The acoustic resonator is used to operate at a frequency of 7.8 GHz.

[0099] When the sound velocity compensation layer 4 is made of silicon carbide and its thickness ratio to that of the interdigitated electrode 3 is 3:1, that is... The acoustic resonator is used to operate at a frequency of 8.4 GHz.

[0100] When the sound velocity compensation layer 4 is made of zinc oxide and its thickness ratio to that of the interdigitated electrode 3 is 2:1, that is... The acoustic resonator is used to operate at a frequency of 7.6 GHz.

[0101] When the sound velocity compensation layer 4 is made of aluminum oxide and its thickness ratio to that of the interdigitated electrode 3 is 9:4, that is... The acoustic resonator is used to operate at a frequency of 8.6 GHz.

[0102] The inventors discovered that, as shown in the test results of the seven sets of comparative experiments above, the thickness ratio of the sound velocity compensation layer 4 and the interdigitated electrode 3 has a significant impact on the operating frequency of the acoustic resonator. By adjusting the thickness ratio of the two, the high-frequency operating performance of the acoustic resonator can be optimized.

[0103] Based on the above description, it can be seen that when At this time, it can enable the acoustic resonator to have a larger operating frequency.

[0104] In other implementation methods, it is also possible to set Although the frequency is reduced to a certain extent, it can be used in work scenarios where high-frequency operation requirements are not high.

[0105] In this embodiment, the groove 41 can be a rectangular groove. In this case, as shown in any of the embodiments of Figures 1-3, the width of the groove 41 remains unchanged in the direction from the substrate 1 to the piezoelectric layer 2.

[0106] Referring to Figure 4, which is a schematic diagram of another acoustic resonator provided in an embodiment of this application, based on the above-described embodiment, in the manner shown in Figure 4, the width of the groove 41 gradually increases in the direction from the substrate 1 to the piezoelectric layer 2. In this manner, the groove 41 can be an inverted trapezoidal trench, with the bottom width of the groove 41 being the smallest and the top opening width of the groove 41 being the largest. From the bottom of the groove 41 to the top opening, the size of the groove 41 gradually increases in the first direction x.

[0107] As shown in Figure 4, in the direction from the substrate 1 to the piezoelectric layer 2, if the width of the groove 41 gradually increases, the interdigitated electrode 3 can cover the irregular thin film on the surface of the groove 41. At this time, h1 > h2, and the irregular thin film covers the bottom of the groove 41 and at least part of the sidewalls.

[0108] Furthermore, as shown in Figure 4, an irregularly shaped thin film can be provided to cover the sidewall of the groove 41 and extend to the outside of the groove 41, covering part of the upper surface of the sound velocity compensation layer 4. The finger strips 30 in two adjacent grooves 41 in the first direction x have an isolation gap 5 on the upper surface of the sound velocity compensation layer 4 between the two grooves 41 to prevent short circuits between adjacent finger strips 30 in the first direction x.

[0109] In the configuration shown in Figure 4, the example of h1 > h2 is used for illustration. If the width of the groove 41 gradually increases in the direction from the substrate 1 to the piezoelectric layer 2, the structure of the acoustic resonator can also be as shown in Figure 5 or Figure 6.

[0110] Referring to Figure 5, which is a schematic diagram of another acoustic resonator provided in the embodiment of this application, based on the above-described implementation, in the manner shown in Figure 5, the width of the groove 41 gradually increases in the direction from the substrate 1 to the piezoelectric layer 2, and h1 = h2.

[0111] Referring to Figure 6, which is a schematic diagram of another acoustic resonator provided in an embodiment of this application, based on the above-described implementation, in the manner shown in Figure 6, the width of the groove 41 gradually increases in the direction from the substrate 1 to the piezoelectric layer 2, and h1 < h2.

[0112] In the direction from substrate 1 to piezoelectric layer 2, if the width of groove 41 gradually increases, the two opposite side walls of groove 41 in the first direction x can have an angle α relative to the plane where piezoelectric layer 2 is located. By adjusting the range of this angle α, the overall waveguide formed by sound velocity compensation layer 4, interdigitated electrodes 3, and piezoelectric layer 2 can better adjust the propagation speed of sound waves in the acoustic resonator, which can effectively improve the performance of the acoustic resonator.

[0113] Optionally, 10° < a < 90° can be set, and further, 30° < a < 80° can be set, so that the overall waveguide formed by the sound velocity compensation layer 4, the interdigital electrode 3 and the piezoelectric layer 2 can better adjust the propagation speed of sound waves in the sound resonator.

[0114] In this embodiment, the thickness of the sound velocity compensation layer 4 ranges from 10 nm to 10000 nm, such as 50 nm, 100 nm, 200 nm, 2500 nm, 4000 nm, 7900 nm, or 9000 nm; the thickness of the interdigital electrode 3 ranges from 10 nm to 10000 nm, such as 20 nm, 300 nm, 1900 nm, 4000 nm, 8000 nm, or 9500 nm; and the thickness of the piezoelectric layer 2 ranges from 10 nm to 10000 nm, such as 10 nm, 100 nm, 2900 nm, 5000 nm, 8900 nm, or 10000 nm. This embodiment does not limit the specific values ​​of different film layers.

[0115] The thickness range of the sound velocity compensation layer 4, the interdigitated electrode 3, and the piezoelectric layer 2 is 10nm to 10000nm. This can avoid the problem of the sound wave resonator being too large due to the excessive thickness of the film layer, and can also avoid the impact on the sound wave propagation speed due to the insufficient thickness of the film layer.

[0116] In this embodiment, the Young's modulus of the sound velocity compensation layer 4 can be set to a range of 5 × 10⁻⁶. 10 Pa ~ 1×10 12 Pa; The density of the sound velocity compensation layer 4 ranges from 2000 kg / m³. 3 ~6000kg / m 3 By selecting different materials within the above parameter range to adjust the Young's modulus and / or material density of the sound velocity compensation layer 4, the bandwidth performance of the acoustic resonator can be better optimized, and the bandwidth of the acoustic resonator can be adjusted. Furthermore, the acoustic performance can be improved, the Q value increased, and the insertion loss reduced by the sound velocity compensation layer 4.

[0117] Optionally, the material of substrate 1 may include a single-layer substrate prepared from any one of silicon, alumina, silicon oxide, glass, aluminum nitride, scandium aluminum nitride, quartz, or silicon carbide, or a multilayer composite substrate formed from multiple of the above materials. This application does not limit the implementation method of substrate 1.

[0118] The piezoelectric layer 2 is made of any one of lithium niobate, lithium tantalate, and aluminum nitride. This application does not limit the implementation method of the piezoelectric layer 2.

[0119] The interdigitated electrode 3 can be fabricated using a metal material with a conductivity greater than 5 × 10⁻⁶. 6Siemens per meter. Select conductivity greater than 5×10⁻⁶. 6 Siemens fabricates interdigitated electrodes 3 using metal material per meter, which can reduce energy loss, help improve signal quality, and enhance the performance of acoustic resonators.

[0120] The metallic materials used to prepare the interdigitated electrodes 3 include any one of gold, silver, copper, aluminum, molybdenum, chromium, nickel, platinum, titanium gold, titanium aluminum, chromium gold, and chromium aluminum.

[0121] The cross-sectional shape of the groove 41 parallel to the first direction x can be any of the following: rectangular (as shown in any of Figures 1-3), trapezoidal (as shown in Figure 5), triangular, partially elliptical, partially circular, and irregular shape, and is not limited to the illustrated method in the embodiments of this application.

[0122] The cross-sectional shape of the interdigitated electrode 3 in the direction parallel to the first direction x can be any of the following: rectangular (as shown in any of the ways in Figures 1-3), trapezoidal (as shown in Figure 5), triangular, partially elliptical, partially circular, or an irregularly shaped thin film with a thickness less than that of the sound velocity compensation layer 4 and covering the surface of the groove 41. It is not limited to the way shown in the embodiments of this application.

[0123] After fabricating the patterned sound velocity compensation layer 4, the interdigitated electrode 3 is fabricated based on the pre-fabricated sound velocity compensation layer 4. Therefore, the patterned structure of the interdigitated electrode 3 is adapted to the patterned structure of the groove 41.

[0124] In this application, the dominant acoustic mode excited by the acoustic resonator can be formed by coupling one or more shear modes, which can improve the electromechanical coupling coefficient k of the acoustic resonator. 2 It can also increase the quality factor Q of the acoustic resonator, expand the operating frequency band of the acoustic resonator, improve the filtering performance of the acoustic resonator, and enhance the sensing sensitivity of the acoustic resonator.

[0125] The dominant acoustic mode excited by the acoustic resonator can be optimized by selecting the appropriate materials for the sound velocity compensation layer 4, the interdigital electrode 3, and the piezoelectric layer 2, or by adjusting the pattern structure and size of the interdigital electrode 3.

[0126] Referring to Figure 7, which is a top view of an electrode pattern in an acoustic resonator provided in an embodiment of this application, the interdigital electrode 3 includes a first interdigital electrode and a second interdigital electrode arranged opposite to each other. The first interdigital electrode and the second interdigital electrode may include one or more finger strips 30 arranged sequentially in the first direction x, and the finger strips 30 of the first interdigital electrode and the second interdigital electrode are arranged alternately in the first direction x.

[0127] If the first interdigital electrode includes a plurality of fingers 30 arranged sequentially in the first direction x, the first interdigital electrode also has a first busbar 31, and all the fingers 30 in the first interdigital electrode are connected to the same side of the first busbar 31.

[0128] If the second interdigital electrode includes a plurality of fingers 30 arranged sequentially in the first direction x, the second interdigital electrode also has a second busbar 32, and all the fingers 30 in the second interdigital electrode are connected to the same side of the second busbar 32.

[0129] Given that the finger strips 30 in the first and second interdigital electrodes are arranged in a periodic, interdigital pattern, the shape of the interdigital electrode 3 can be set according to requirements and is not limited to the form shown in the embodiments of this application.

[0130] The first busbar 31 and the second busbar 32 are arranged parallel to each other in the second direction y. The second direction y is parallel to the plane where the piezoelectric layer 2 is located and perpendicular to the first direction x.

[0131] Optionally, the piezoelectric layer 2 may also be provided with two reflective gratings 6 arranged opposite each other in the first direction x, with the interdigitated electrode 3 located between the two reflective gratings 6. The reflective gratings 6 can reflect sound waves to improve energy utilization, extend the sound wave propagation path, improve the quality factor of the sound wave resonator, and improve the out-of-band rejection and in-band insertion loss of the sound wave resonator, making the filter response smoother and enhancing its application range in high-frequency and high-performance environments.

[0132] The reflective grating 6 includes multiple metal gratings arranged sequentially in the first direction x and two busbars positioned opposite each other in the second direction y. The two ends of the metal gratings opposite each other in the second direction y are respectively connected to one of the busbars of the reflective grating 6. At this time, the reflective grating 6 is also located in the groove corresponding to the sound velocity compensation layer 4.

[0133] The reflective gate 6 and the interdigitated electrode 3 can be fabricated simultaneously on the same metal layer. To facilitate the same fabrication process for the reflective gate 6, two reflective gates 6 can be symmetrically arranged on both sides of the interdigitated electrode 3.

[0134] The reflective grating 6 and the interdigitated electrode 3 can be made of the same material, both having a conductivity greater than 5 × 10⁻⁶. 6 Siemens metal per meter.

[0135] In the same reflective grating 6, the number of metal fingers can be 10 to 60, such as 10, 15, 30, 45 or 60, etc. In this embodiment, the number of metal fingers in the reflective grating 6 is not limited.

[0136] The thickness of the reflective grating 6 can be the same as or different from the thickness of the interdigitated electrode 3. The reflective thickness of the reflective grating 6 can range from 10 nm to 10,000 nm. For example, it can be 10 nm, 100 nm, 2900 nm, 5000 nm, 8900 nm, 90000 nm, or 10000 nm, etc. The embodiments of this application do not limit the thickness of the reflective grating 6.

[0137] In the reflective grating 6, the width of the metal grating strip in the first direction x can be 0.001μm to 10μm, such as 0.001μm, 1μm, 2.6μm, 4.1μm, 7μm, 9.6μm or 10μm, etc. The embodiments of this application do not limit the value of the metal grating strip.

[0138] The length of the metal grid strip in the second direction y can be equal to or not equal to the length of the finger strip 30 in the interdigital electrode 3. To improve the sound wave reflection effect, it is preferable to set the length of the metal grid strip to be greater than the length of the finger strip 30.

[0139] The length of the metal grid can range from 1 μm to 500 μm. For example, it can be 1 μm, 80 μm, 250 μm, 360 μm, 499 μm, and 500 μm, etc. The embodiments of this application do not limit the length of the metal grid.

[0140] The number of interdigital electrodes 30 can be 2 to 500, such as 2, 100, 200, 250, 380 or 500.

[0141] The thickness of the finger strip 30 can be from 10nm to 10000nm. For example, the thickness of the finger strip 30 can be 10nm, 100nm, 2900nm, 5000nm, 8900nm or 10000nm, etc.

[0142] The width of the finger strip 30 in the first direction x can be in the range of 0.001μm to 10μm. For example, the width of the finger strip 30 can be 0.001μm, 1μm, 2.6μm, 4.1μm, 7μm, 9.6μm or 10μm.

[0143] The length of the finger strip 30 in the second direction y can range from 1 μm to 500 μm. For example, the length of each interdigital electrode 3 can be 1 μm, 80 μm, 250 μm, 360 μm, 499 μm or 500 μm.

[0144] To facilitate the fabrication of the interdigitated electrode 3, each finger strip 30 in the interdigitated electrode 3 is configured to have the same length, thickness, and width. Alternatively, at least two finger strips 30 may have different lengths, widths, or thicknesses.

[0145] The performance of the acoustic resonator based on the technical solution of this application will be further described below, based on relevant experimental simulation data.

[0146] Referring to Figure 8, which is a cross-sectional schematic diagram of an acoustic resonator operating at a frequency of 6.2 GHz according to an embodiment of this application, in which the sound velocity compensation layer 4 is zinc oxide and the interdigitated electrodes 3 are made of aluminum. h1 = 20 nm, h2 = 80 nm, and the finger strips 30 are embedded in the groove 41. The duty cycle of the finger strips 30 (i.e., the ratio of the width of the finger strips 30 in the first direction x to the spacing between the finger strips 30) is 50%. The tangential direction of the piezoelectric layer 2 can be X-cut lithium niobate, and the Euler angle of the piezoelectric layer 2 is -5°. The horizontal wavelength λ is defined as the sum of twice the width of the finger strips 30 and twice the spacing between adjacent finger strips 30, which is 600 nm. The ratio of the horizontal wavelength λ to the thickness of the piezoelectric layer 2 is 2:1. Based on this embodiment, the acoustic resonator can be used to operate at a frequency of 6.2 GHz.

[0147] Referring to Figure 9, which shows the simulated admittance curve for an acoustic resonator operating at a frequency of 6.2 GHz. In the simulated admittance curve shown in Figure 9, the horizontal axis represents frequency / GHz, and the vertical axis represents admittance / dB. When the acoustic resonator operates at a frequency of 6.2 GHz, the electromechanical coupling coefficient k... 2 Approximately 35%. Among them, the electromechanical coupling coefficient k... 2 It can be calculated using the following formula (4):

[0148] In formula (4), f s To simulate the frequency of the highest admittance point in the admittance curve, f p This is the frequency at which the admittance is lowest in the simulated admittance curve.

[0149] Referring to Figure 10, which is a cross-sectional schematic diagram of an acoustic resonator operating at a frequency of 4.6 GHz according to an embodiment of this application, in which the sound velocity compensation layer 4 is silicon oxide and the interdigitated electrodes 3 are made of aluminum. h1 = 220 nm, h2 = 80 nm, and the fingers 30 within the groove 41 are completely embedded in the groove 41. The duty cycle of the fingers 30 is 50%. The piezoelectric layer 2 can be X-shaped lithium niobate, and the Euler angle of the piezoelectric layer 2 is -5°. The horizontal wavelength λ is defined as the sum of twice the width of the fingers 30 and twice the spacing between adjacent fingers 30, which is 1000 nm. The ratio of the horizontal wavelength λ to the thickness of the piezoelectric layer 2 is 10:3. Based on this embodiment, the acoustic resonator can be used to operate at a frequency of 4.6 GHz.

[0150] Referring to Figure 11, Figure 11 shows the simulated admittance curve for an acoustic resonator operating at a frequency of 4.6 GHz. In the simulated admittance curve shown in Figure 11, the horizontal axis represents frequency / GHz, and the vertical axis represents admittance / dB. When the acoustic resonator operates at a frequency of 4.6 GHz, the electromechanical coupling coefficient k... 2 Approximately greater than 31%. Among them, the electromechanical coupling coefficient k... 2 It can be calculated using the formula (4) above.

[0151] Referring to Figure 12, which shows the simulated admittance curve for an acoustic resonator operating at a frequency of 6.9 GHz. In the simulated admittance curve shown in Figure 12, the horizontal axis represents frequency / GHz, and the vertical axis represents admittance / dB. When the acoustic resonator operates at a frequency of 6.9 GHz, the electromechanical coupling coefficient k... 2 Greater than 25%. Among them, the electromechanical coupling coefficient k 2 It can be calculated using the above formula (4).

[0152] In the acoustic resonator corresponding to Figure 12, the sound velocity compensation layer 4 is made of silicon oxide, and the interdigitated electrodes 3 are made of aluminum. h1 = 200 nm, h2 = 80 nm, and the fingers 30 within the groove 41 are completely embedded in the groove 41. The duty cycle of the fingers 30 is 50%. The tangential orientation of the piezoelectric layer 2 can be X-cut lithium niobate, and the Euler angle of the piezoelectric layer 2 is -5°. The horizontal wavelength λ is defined as the sum of twice the width of the fingers 30 and twice the spacing between adjacent fingers 30, which is 600 nm. The ratio of the horizontal wavelength λ to the thickness of the piezoelectric layer 2 is 2:1. Based on this design, the acoustic resonator can be used to operate at a frequency of 6.9 GHz, with an electromechanical coupling coefficient k. 2 Greater than 25%.

[0153] Referring to Figure 13, which shows the simulated admittance curve for an acoustic resonator operating at a frequency of 7.8 GHz. In the simulated admittance curve shown in Figure 13, the horizontal axis represents frequency / GHz, and the vertical axis represents admittance / dB. When the acoustic resonator operates at a frequency of 7.8 GHz, the electromechanical coupling coefficient k... 2 Greater than 25%. Among them, the electromechanical coupling coefficient k 2 It can be calculated using the above formula (4).

[0154] In the acoustic resonator corresponding to Figure 13, the sound velocity compensation layer 4 is made of silicon nitride, and the interdigitated electrodes 3 are made of aluminum. h1 = 160 nm, h2 = 80 nm, and the fingers 30 in each groove 41 are completely embedded in the groove 41. The duty cycle of the fingers 30 is 50%. The tangential orientation of the piezoelectric layer 2 can be X-cut lithium niobate, and the Euler angle of the piezoelectric layer 2 is -5°. The horizontal wavelength λ is defined as the sum of twice the width of the fingers 30 and twice the spacing between adjacent fingers 30, which is 600 nm. The ratio of the horizontal wavelength λ to the thickness of the piezoelectric layer 2 is 2:1. Based on the above design, the acoustic resonator can be used to operate at a frequency of 7.8 GHz, and the electromechanical coupling coefficient k 2 Greater than 14%.

[0155] Referring to Figure 14, which shows the simulated admittance curve for an acoustic resonator operating at 8.4 GHz, the horizontal axis represents frequency in GHz and the vertical axis represents admittance in dB. When the acoustic resonator operates at 8.4 GHz, the electromechanical coupling coefficient k... 2 Greater than 9%. Among them, the electromechanical coupling coefficient k 2 It can be calculated using the above formula (4).

[0156] In the acoustic resonator corresponding to Figure 14, the structural sound velocity compensation layer 4 is made of silicon carbide, and the interdigitated electrodes 3 are made of aluminum. h1 = 180 nm, h2 = 60 nm, and the fingers 30 in each groove 41 are completely embedded in the groove 41. The duty cycle of the fingers 30 is 50%. The tangential orientation of the piezoelectric layer 2 can be X-cut lithium niobate, and the Euler angle of the piezoelectric layer 2 is -5°. The horizontal wavelength λ is defined as the sum of twice the width of the fingers 30 and twice the spacing between adjacent fingers 30, which is 600 nm. The ratio of the horizontal wavelength λ to the thickness of the piezoelectric layer 2 is 2:1. Based on the above design, the acoustic resonator can be used to operate at a frequency of 8.4 GHz with an electromechanical coupling coefficient greater than 9%.

[0157] Referring to Figure 15, which shows the simulated admittance curve for an acoustic resonator operating at 7.6 GHz, the horizontal axis represents frequency in GHz and the vertical axis represents admittance in dB. When the acoustic resonator operates at 7.6 GHz, the electromechanical coupling coefficient k... 2 Greater than 19%. Among them, the electromechanical coupling coefficient k 2 It can be calculated using the above formula (4).

[0158] In the acoustic resonator corresponding to Figure 15, the sound velocity compensation layer 4 is zinc oxide, and the interdigitated electrode 3 is aluminum. h1 = 120 nm, h2 = 60 nm, and the fingers 30 in each groove 41 are completely embedded in the groove 41. The duty cycle of the fingers 30 is 50%. The tangential orientation of the piezoelectric layer 2 can be X-cut lithium niobate, and the Euler angle of the piezoelectric layer 2 is -5°. The horizontal wavelength λ is defined as the sum of twice the width of the fingers 30 and twice the spacing between adjacent fingers 30, which is 600 nm. The ratio of the horizontal wavelength λ to the thickness of the piezoelectric layer 2 is 2:1. Based on the above design, the acoustic resonator can be used to operate at a frequency of 7.6 GHz with an electromechanical coupling coefficient greater than 19%.

[0159] Referring to Figure 16, which shows the simulated admittance curve for an acoustic resonator operating at 8.6 GHz, the horizontal axis represents frequency in GHz and the vertical axis represents admittance in dB. When the acoustic resonator operates at 8.6 GHz, the electromechanical coupling coefficient k... 2 Greater than 16%. Among them, the electromechanical coupling coefficient k 2 It can be calculated using the above formula (4).

[0160] In the acoustic resonator corresponding to Figure 16, the sound velocity compensation layer 4 is made of aluminum oxide, and the interdigitated electrodes 3 are made of metallic aluminum. h1 = 180 nm, h2 = 80 nm, and the interdigitated electrodes 3 in each groove 41 are completely embedded in the groove 41. The duty cycle of the fingers 30 is 50%. The tangential orientation of the piezoelectric layer 2 can be X-cut lithium niobate, and the Euler angle of the piezoelectric layer 2 is -5°. The horizontal wavelength λ is defined as the sum of twice the width of the fingers 30 and twice the spacing between adjacent fingers 30, which is 600 nm. The ratio of the horizontal wavelength λ to the thickness of the piezoelectric layer 2 is 2:1. Based on the above design, the acoustic resonator can be used to operate at a frequency of 8.6 GHz with an electromechanical coupling coefficient greater than 16%.

[0161] The simulation data above shows that, in this embodiment, by designing the depth of the groove 41 in the sound velocity compensation layer 4, the thickness of the interdigital electrode 3, and the duty cycle, the sound velocity compensation layer 4, the interdigital electrode 3, and the piezoelectric layer 2 form an integral waveguide. This allows the interdigital electrode 3 to participate more effectively in the propagation of sound waves and reduces energy dissipation caused by scattering. Thus, while increasing the frequency, there is no need to reduce the size of the interdigital electrode 3, and the resistance of the interdigital electrode 3 will not increase, avoiding a decrease in the quality factor of the acoustic resonator and achieving a high-quality acoustic resonator. Moreover, when the ratio of the horizontal wavelength to the thickness of the piezoelectric layer 2 remains constant, the operating frequency of the acoustic resonator can range from tens of MHz to tens of GHz while maintaining a large quality factor, which can well meet the current frequency band's requirements for high-frequency and high-quality filter performance.

[0162] In the above embodiments, the uniform thickness of the sound velocity compensation layer 4 is used as an example for illustration. In other embodiments of this application, the sound velocity compensation layer 4 may also be a film layer with a gradually changing thickness. If the sound velocity compensation layer 4 is a film layer with a gradually changing thickness, the thickness of the sound velocity compensation layer 4 between two adjacent grooves 41 remains uniform in the first direction x. In this case, in the above embodiments, the value of h1 can be the average thickness of the sound velocity compensation layer 4, or the minimum thickness of the sound velocity compensation layer 4 can be equivalent to h1.

[0163] Referring to Figure 17, which is a cross-sectional view of another acoustic resonator provided in an embodiment of this application, based on the above embodiment, in the manner shown in Figure 17, along the first direction x, the sound velocity compensation layer 4 is a film layer with a gradually varying thickness. The thickness of the sound velocity compensation layer 4 between two adjacent grooves 41 is uniform and constant, while the thickness of the sound velocity compensation layer 4 between different grooves 41 changes periodically with alternating intervals of h11 and h12, where h11 > h12. In this case, the thickness h2 of the interdigitated electrode 3 is set to be no greater than h12.

[0164] In the configuration shown in Figure 17, the sound velocity compensation layer 4 with periodically varying thickness can optimize the performance of the overall waveguide sound velocity propagation formed by the sound velocity compensation layer 4, interdigitated electrodes 3, and piezoelectric layer 2, thereby optimizing the performance of the acoustic resonator.

[0165] Referring to Figure 18, which is a cross-sectional view of another acoustic resonator provided in an embodiment of this application, based on the above embodiment, in the manner shown in Figure 18, along the first direction x, the sound velocity compensation layer 4 is a film layer with a gradually changing thickness. The thickness of the sound velocity compensation layer 4 between two adjacent grooves 41 is uniform and constant. The thickness of the sound velocity compensation layer 4 between different grooves 41 gradually decreases from h to h', and then gradually increases from h' to h. At this time, the thickness h2 of the interdigitated electrode 3 is set to be no greater than h'.

[0166] In the manner shown in Figure 18, the sound velocity compensation layer 4 with gradually varying thickness can also optimize the performance of the overall waveguide sound velocity propagation formed by the sound velocity compensation layer 4, the interdigitated electrode 3, and the piezoelectric layer 2, thereby optimizing the performance of the acoustic resonator.

[0167] Along the first direction x, if the sound velocity compensation layer 4 is a film layer with a gradually varying thickness, the thickness of the sound velocity compensation layer 4 between two adjacent grooves 41 can be set to be uniform and constant. The thickness of the sound velocity compensation layer 4 between different grooves 41 gradually increases from h' to h, and then gradually decreases from h to h'. In this case, the thickness h2 of the interdigital electrode 3 is also set to be no greater than h'. This method can also optimize the sound velocity propagation performance of the overall waveguide formed by the sound velocity compensation layer 4, the interdigital electrode 3, and the piezoelectric layer 2 based on the gradually varying thickness of the sound velocity compensation layer 4, thereby optimizing the performance of the acoustic resonator.

[0168] Based on the acoustic resonator provided in the above embodiments, another embodiment of this application provides a method for preparing an acoustic resonator, which can be shown in FIG17 and can be used to prepare the acoustic resonator provided in any of the above embodiments.

[0169] Referring to Figure 19, which is a flowchart illustrating a method for fabricating an acoustic resonator according to an embodiment of this application, and in conjunction with Figure 19 and the acoustic resonator drawings provided in the above embodiments, the fabrication method includes:

[0170] Step S11: Form a piezoelectric layer 2 on the surface of substrate 1.

[0171] Step S12: A sound velocity compensation layer 4 is formed on the side surface of the piezoelectric layer 2 facing away from the substrate 1. The sound velocity compensation layer 4 has a plurality of grooves 41 arranged sequentially along the first direction x. The first direction x is parallel to the plane where the piezoelectric layer 2 is located.

[0172] Step S13: Based on the sound velocity compensation layer 4 with groove 41, interdigitated electrodes 3 are formed on the surface of the piezoelectric layer 2 away from the substrate 1. The interdigitated electrodes 3 include a plurality of fingers 30 that are arranged one-to-one with the groove 41. The fingers 30 make electrical contact with the piezoelectric layer 2 based on the corresponding groove 41.

[0173] In this embodiment, a patterned sound velocity compensation layer 4 with grooves 41 is first formed. Then, interdigitated electrodes 3 that are electrically in contact with the piezoelectric layer 2 are formed based on the sound velocity compensation layer 4, such that the fingers 30 in the interdigitated electrodes 3 are respectively located in the corresponding grooves 41. In this way, the sound velocity compensation layer 4, the interdigitated electrodes 3 and the piezoelectric layer 2 can form an integral waveguide. Based on this integral waveguide, the performance of the acoustic resonator can be optimized.

[0174] The ratio of the thickness h1 of the sound velocity compensation layer 4 to the thickness h2 of the interdigital electrode 3 can be 1:4, 11:4, 5:2, 2:1, 3:1, or 9:4. The operating frequency of the acoustic resonator can be adjusted by changing the materials and thickness ratio of the interdigital electrode 3 and the sound velocity compensation layer 4.

[0175] Based on the above embodiments, another embodiment of this application provides a filter, which includes the acoustic resonator provided in any of the above embodiments.

[0176] Based on the above embodiments, another embodiment of this application also provides an electronic device, which includes the electronic device provided in any of the above embodiments.

[0177] The various embodiments in this application are described in a progressive, parallel, or combined manner. Each embodiment focuses on its differences from other embodiments, and similar or identical parts between embodiments can be referred to interchangeably. The embodiments provided in this application can be combined with each other without contradiction.

[0178] It should be noted that, in the description of this application, the accompanying drawings and embodiments are illustrative rather than restrictive. The same reference numerals throughout the embodiments identify the same structures. Additionally, for ease of understanding and description, the thicknesses of some layers, films, panels, regions, etc., may be exaggerated in the drawings. It is also understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, the element may be directly on the other element or there may be intermediate elements. Furthermore, "on" means positioning an element on or below another element, but does not inherently mean positioning it above another element according to the direction of gravity.

[0179] The terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component positioned centrally in the middle.

[0180] It should also be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes the aforementioned element.

[0181] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An acoustic resonator, characterized in that, include: Substrate; A piezoelectric layer disposed on the surface of the substrate; A sound velocity compensation layer is disposed on the surface of the piezoelectric layer facing away from the substrate, the sound velocity compensation layer having a plurality of grooves arranged sequentially along a first direction; the first direction is parallel to the plane of the piezoelectric layer. An interdigitated electrode is formed on the surface of the piezoelectric layer opposite to the substrate, based on the sound velocity compensation layer having the grooves; the interdigitated electrode includes a plurality of fingers arranged one-to-one with the grooves; the fingers make electrical contact with the piezoelectric layer based on the corresponding grooves.

2. The acoustic resonator according to claim 1, characterized in that, The sound velocity of the sound velocity compensation layer is not less than the sound velocity of the piezoelectric layer and the interdigitated electrode.

3. The acoustic resonator according to claim 1, characterized in that, The thickness of the sound velocity compensation layer is h1, and the material density of the sound velocity compensation layer is ρ1; The thickness of the interdigitated electrode is h2, and the material density of the interdigitated electrode is ρ2; Wherein, ρ1·h1=A·ρ2·h2; where A is a set constant.

4. The acoustic resonator according to claim 3, characterized in that, 2≤A≤10。 5. The acoustic resonator according to claim 1, characterized in that, The thickness of the sound velocity compensation layer is h1, and the thickness of the interdigitated electrodes is h2. in, 6. The acoustic resonator according to claim 1, characterized in that, In the direction from the substrate to the piezoelectric layer, the width of the groove remains constant; or, the width of the groove gradually increases.

7. The acoustic resonator according to any one of claims 1-6, characterized in that, The thickness of the sound velocity compensation layer ranges from 10 nm to 10,000 nm; The thickness of the finger strip ranges from 10 nm to 10,000 nm; The thickness of the piezoelectric layer ranges from 10 nm to 10,000 nm.

8. The acoustic resonator according to any one of claims 1-6, characterized in that, The Young's modulus of the sound velocity compensation layer is in the range of 5 × 10⁻⁶. 10 Pa ~ 1×10 12 Pa; The density of the sound velocity compensation layer is in the range of 2000 kg / m³. 3 ~6000kg / m 3 .

9. A method for fabricating an acoustic resonator, characterized in that, include: Provide a substrate; A piezoelectric layer is formed on the surface of the substrate; A sound velocity compensation layer is formed on the surface of the piezoelectric layer facing away from the substrate. The sound velocity compensation layer has a plurality of grooves arranged sequentially along a first direction. The first direction is parallel to the plane in which the piezoelectric layer is located. Based on the sound velocity compensation layer having the grooves, interdigitated electrodes are formed on the surface of the piezoelectric layer facing away from the substrate. The interdigitated electrodes include a plurality of fingers that are arranged one-to-one with the grooves. The fingers make electrical contact with the piezoelectric layer based on the corresponding grooves.

10. An electronic device, characterized in that, Including the acoustic resonator as described in any one of claims 1-8.

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