An acoustic wave resonator and a communication device

Abstract

This invention relates to the field of microelectronics, and particularly to an acoustic resonator and communication device. The acoustic resonator includes a supporting substrate and an upper structure; the upper structure includes stacked electrode layers and piezoelectric layers; the upper structure can be divided from the outside to the inside into a peripheral region, a connection region, and a resonant region; the resonant region is located in the hollow area of ​​the peripheral region and is connected to the peripheral region through the connection region; the connection region and the resonant region are suspended on the supporting substrate; wherein, the piezoelectric layer in the resonant region is made of a piezoelectric material, and the width of the piezoelectric layer in the connection region is smaller than the width of the piezoelectric layer in the resonant region, or, if an edge region is provided at the connection between the connection region and the resonant region, the width of the piezoelectric layer in the edge region is greater than the width of the piezoelectric layer in the resonant region, or the thickness of the piezoelectric layer in the connection region is less than the thickness of the piezoelectric layer in the resonant region. This can enhance the reflection of modes at the edge of the resonant region, or change the mode displacement distribution to suppress transverse higher-order modes.

Description

Technical Field

[0001] This invention relates to the field of microelectronics technology, and in particular to an acoustic resonator and communication device. Background Technology

[0002] Acoustic filters, including bulk acoustic wave (BAW) and surface acoustic wave (SAW) filter technologies, are currently the most widely used technologies in the RF front-end field. However, with the development of fifth-generation (5G) and future wireless communication systems towards higher frequency bands and larger bandwidths, traditional SAW and BAW filters, due to their inherent physical limitations in sound velocity or electromechanical coupling coefficients, can no longer simultaneously meet the system's performance requirements for high-frequency operation and large bandwidth.

[0003] To overcome these limitations, the industry has proposed various improvement schemes. For example, patent document CN120281286A discloses a structure composed of a strip-shaped piezoelectric layer and electrodes, which improves the operating frequency and bandwidth by exciting dual-shear mode bulk acoustic waves. However, this scheme usually requires designing the resonant region as a slender structure to weaken the influence of transverse higher-order modes. This not only brings manufacturing and practical problems such as poor mechanical reliability and heat dissipation difficulties, but also the suppression effect on parasitic modes is not ideal.

[0004] Therefore, how to reduce the fabrication difficulty of resonators and effectively suppress transverse high-order modes while ensuring high-frequency broadband performance has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] To address the aforementioned technical problems, this application discloses an acoustic resonator, which includes at least: Support substrate; The upper structure includes a stacked electrode layer and a piezoelectric layer. The upper structure can be divided into a peripheral region, a connection region, and a resonant region from the outside to the inside. The resonant region is located in the hollow area of ​​the peripheral region and is connected to the peripheral region through the connection region. The connection region and the resonant region are suspended on the supporting substrate. Wherein, the material of the piezoelectric layer located in the resonant region is a piezoelectric material, and the width of at least one piezoelectric layer located in the connection region is smaller than the width of the piezoelectric layer located in the resonant region; and / or, if an edge region is provided at the connection between the connection region and the resonant region, the width of at least one piezoelectric layer located in the edge region is greater than the width of the piezoelectric layer located in the resonant region; and / or, the thickness of at least one piezoelectric layer located in the connection region is less than the thickness of the piezoelectric layer located in the resonant region.

[0006] Optionally, the width of the edge region is greater than the width of the central region of the resonant region; At least one of the two ends of the resonant region is provided with the edge region at the corresponding end, and / or part or all of the edge region is located at the end of the connection region near the resonant region.

[0007] Optionally, the shape of the edge region in the top view is one of a rectangle, triangle, polygon, and ellipse.

[0008] Optionally, the material of the piezoelectric layer located in the edge region is the same as the material of the piezoelectric layer located in the resonant region.

[0009] Optionally, the materials of the peripheral region, the connecting region, and the piezoelectric layer located in the resonant region are different, or at least two regions are made of the same material.

[0010] Optionally, when the width of the piezoelectric layer in the connection region is smaller than the width of the piezoelectric layer in the resonant region, and the material of the piezoelectric layer in the connection region is the same as the material of the piezoelectric layer in the resonant region, the width of the connection region satisfies [0.1W1, 0.6W1]; where W1 represents the width of the piezoelectric layer in the central region of the resonant region.

[0011] Optionally, when the width of the piezoelectric layer in the connection region is smaller than the width of the piezoelectric layer in the resonant region, and the material of the piezoelectric layer in the connection region is different from the material of the piezoelectric layer in the resonant region, the width of the connection region satisfies [0.1W1, W1); where W1 represents the width of the piezoelectric layer in the central region of the resonant region.

[0012] Optionally, when the material of the piezoelectric layer in the connection region is the same as the material of the piezoelectric layer in the resonant region, the thickness of the piezoelectric layer in the connection region satisfies [0.1h1, 0.6h1]; where h1 represents the thickness of the piezoelectric layer in the central region of the resonant region.

[0013] Optionally, when the thickness of the piezoelectric layer in the connection region is less than the thickness of the piezoelectric layer in the resonant region, and the material of the piezoelectric layer in the connection region is different from the material of the piezoelectric layer in the resonant region, the thickness of the connection region satisfies [0.1h1, h1); where h1 represents the thickness of the piezoelectric layer in the central region of the resonant region.

[0014] Optionally, the width of the piezoelectric layer located in the edge region is greater than the width of the piezoelectric layer located in the central region of the resonant region, and the width of the piezoelectric layer located in the connection region is less than the width of the piezoelectric layer located in the central region of the resonant region.

[0015] Optionally, the width of the piezoelectric layer located in the edge region is greater than the width of the piezoelectric layer located in the center region of the resonant region, and the thickness of the piezoelectric layer located in the connection region is less than the thickness of the piezoelectric layer located in the center region of the resonant region.

[0016] Optionally, the thickness of the piezoelectric layer located in the connection region is less than the thickness of the piezoelectric layer located in the central region of the resonant region.

[0017] Optionally, the length of the resonant region is greater than 10 times the width of the piezoelectric layer located in the resonant region.

[0018] Optionally, the length of the resonant region is less than 100 times the width of the piezoelectric layer located in the resonant region.

[0019] Optionally, it includes N resonant regions and 2N connection regions; where N is an integer greater than or equal to 1. One end of each of the resonant regions is connected to the peripheral region through one of the connection regions, and the other end is connected to the peripheral region through another connection region; The plurality of resonant regions are arranged at intervals along a first direction; the first direction is the length extension direction of the busbar of the electrode layer.

[0020] Optionally, the material of the peripheral region is a conductive material.

[0021] Optionally, a dielectric layer may also be included; The outer layer is connected to the supporting substrate through the dielectric layer; The dielectric layer may be a single-layer material or a multi-layer material; The material of the dielectric layer includes one or more of silicon oxide, silicon nitride, polycrystalline silicon, amorphous silicon, aluminum oxide, and aluminum nitride; The dielectric layer is one or more of the following: sacrificial layer, temperature compensation layer, heat dissipation layer, trap-rich layer, bonding layer, low-velocity layer, and dispersion modulation layer.

[0022] Optionally, the material of the piezoelectric layer located in the resonant region is one of lithium tantalate, lithium niobate, aluminum nitride, aluminum nitride-doped, lead zirconate titanate, or lead magnesium niobate-lead titanate. At least one of the absolute values ​​of the piezoelectric coefficients e33, e34, and e35 of the piezoelectric layer located in the resonant region along the width direction of the resonant region is not less than 1 C / m. 2 Alternatively, the sum of the absolute values ​​of the piezoelectric coefficients e31, e33, and e35 is not less than 1 C / m. 2 .

[0023] Optionally, the target mode of the acoustic resonator is a higher-order mode of the horizontal shear mode, vertical shear mode, or thickness expansion mode; the higher-order mode is a mode with an order greater than or equal to 1.

[0024] On the other hand, this application also discloses a communication device that includes at least the aforementioned acoustic resonator; the communication device includes any one of a filter, a duplexer, a multiplexer, and a filter module.

[0025] This application provides an acoustic resonator, comprising at least a supporting substrate and an upper structure. The upper structure includes stacked electrode layers and piezoelectric layers. The upper structure can be divided from the outside to the inside into a peripheral region, a connecting region, and a resonant region. The resonant region is located in the hollow area of ​​the peripheral region and is connected to the peripheral region through the connecting region. The connecting region and the resonant region are suspended on the supporting substrate. The piezoelectric layer in the resonant region is made of a piezoelectric material, and the width of the piezoelectric layer in the connecting region is smaller than the width of the piezoelectric layer in the resonant region. Furthermore, if an edge region is provided at the connection between the connecting region and the resonant region, the width of the piezoelectric layer in the edge region is greater than the width of the piezoelectric layer in the resonant region. And / or, the thickness of the piezoelectric layer in the connecting region is less than the thickness of the piezoelectric layer in the resonant region. This allows for enhanced mode reflection at the edge of the resonant region or alteration of the mode displacement distribution to suppress laterally higher-order modes. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a cross-sectional view of a first type of acoustic resonator exemplified in this application; Figure 2 for Figure 1 Exploded views of the corresponding piezoelectric and electrode layers; Figure 3 for Figure 1 The corresponding top view; Figure 4 for Figure 3 Corresponding cross-sectional view; Figure 5 This is an exemplary comparative cross-sectional view of this application; Figure 6 for Figure 5 The corresponding top view; Figure 7 This application provides an exemplary set of comparative curves showing the electromechanical coupling coefficient as a function of in-plane orientation. Figure 8This is another set of admittance curves that serve as an example of this application; Figure 9 An exemplary comparative admittance / conductance curve for this application; Figure 10 This is a top view of a second type of acoustic resonator exemplified in this application; Figure 11 This is a top view of a third type of acoustic resonator exemplified in this application; Figure 12 The curves showing the variation of the resonant frequency of a set of acoustic resonators with respect to the width of the piezoelectric layer are exemplary in this application. Figure 13 Admittance / conductance curves for Example 1 and Comparative Example 1, which are exemplary examples of this application; Figure 14 This is a top view of a fourth type of acoustic resonator exemplified in this application; Figure 15 A top view of a fifth acoustic resonator exemplified in this application; Figure 16 A top view of a sixth type of acoustic resonator exemplified in this application; Figure 17 This is a top view of a seventh type of acoustic resonator exemplified in this application; Figure 18 This is a top view of an exemplary eighth acoustic resonator of this application; Figure 19 This is a top view of a ninth type of acoustic resonator exemplified in this application; Figure 20 This is a top view of a tenth type of acoustic resonator exemplified in this application; Figure 21 This is a top view of an eleventh acoustic resonator exemplified in this application; Figure 22 This is a top view of the twelfth type of acoustic resonator exemplified in this application; Figure 23 This is a top view of the thirteenth acoustic resonator exemplified in this application; Figure 24 The admittance curve is an exemplary example 2 of this application; Figure 25 This is a cross-sectional view of the fourteenth acoustic resonator exemplified in this application; Figure 26 This is a cross-sectional view of the fifteenth type of acoustic resonator exemplified in this application; Figure 27 A cross-sectional view of the sixteenth type of acoustic resonator exemplified in this application; Figure 28 This is a top view of the seventeenth type of acoustic resonator exemplified in this application; Figure 29 Admittance curves for a first set of exemplary examples of this application; Figure 30 Admittance curves for a second set of exemplary examples of this application; Figure 31 This is a top view of the eighteenth type of acoustic resonator exemplified in this application; Figure 32 This is a top view of the nineteenth type of acoustic resonator exemplified in this application; Figure 33 This is a top view of the twentieth type of acoustic resonator exemplified in this application; Figure 34 This is a top view of the twenty-first acoustic resonator exemplified in this application; Figure 35 This is a top view of the twenty-second exemplary acoustic resonator of this application; Figure 36 Admittance / conductance curves for a third set of examples exemplified in this application; Figure 37 This is a cross-sectional view of the twenty-third type of acoustic resonator exemplified in this application; Figure 38 This is a cross-sectional view of the twenty-fourth type of acoustic resonator exemplified in this application; Figure 39 The admittance curve is an exemplary example 3 of this application; Figure 40 This is a cross-sectional view of the twenty-fifth type of acoustic resonator exemplified in this application; Figure 41 for Figure 40 The corresponding top view.

[0028] The following is supplementary explanation of the attached figures: 1-Supporting substrate; 2-Bottom electrode; 3-Piezoelectric layer; 301-First piezoelectric region; 302-Second piezoelectric region; 303-Third piezoelectric region; 4-Top electrode; 5-Busbar; 6-Electrode finger; 7-Peripheral region; 8-Connection region; 801-First connection unit; 802-Second connection unit; 9-Resonant region; 10-Edge region; 101-First edge unit; 102-Second edge unit; 11-Dielectric layer; 12-Cavity; 13-Resonant center region. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0030] The term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of this application. In the description of this application, it should be understood that the terms "upper," "lower," "top," "bottom," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and 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, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Moreover, the terms "first," "second," etc., 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 this application described herein can be implemented in orders other than those illustrated or described herein.

[0031] Although the numerical ranges and parameters illustrating the broad scope of the invention are approximate, the values ​​listed in the specific examples are reported as precisely as possible. However, any numerical value inherently contains some error that is necessarily caused by the standard deviation found in their respective test measurements.

[0032] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Optionally, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Furthermore, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are included. For example, a specified range from “1 to 10” should be considered to include any and all subranges between the minimum value 1 and the maximum value 10. Exemplary subranges of the range 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, etc.

[0033] Please see Figure 1The diagram shown is a cross-sectional view of a first type of acoustic resonator exemplified in this application. Specifically, the acoustic resonator includes at least: a supporting substrate 1; and an upper structure; the upper structure includes stacked electrode layers and piezoelectric layers 3; the upper structure can be divided into an outer peripheral region 7, a connecting region 8, and a resonant region 9 from the outside to the inside; the resonant region 9 is located in the hollow region of the outer peripheral region 7 and is connected to the outer peripheral region 7 through the connecting region 8; the connecting region 8 and the resonant region 9 are suspended on the supporting substrate 1; wherein, the material of the piezoelectric layer 3 located in the resonant region 9 is a piezoelectric material, and at least one location of the piezoelectric layer 3 located in the connecting region 8 has a width smaller than the width of the piezoelectric layer 3 located in the resonant region 9; and / or, when an edge region 10 is provided at the connection between the connecting region 8 and the resonant region 9, at least one location of the piezoelectric layer 3 located in the edge region 10 has a width greater than the width of the piezoelectric layer 3 located in the resonant region 9; and / or, at least one location of the piezoelectric layer 3 located in the connecting region 8 has a thickness smaller than the thickness of the piezoelectric layer 3 located in the resonant region 9.

[0034] In this embodiment, the acoustic resonator satisfies at least one of the following three conditions: Condition 1: the width of at least one piezoelectric layer 3 located in the connection region 8 is less than the width of the piezoelectric layer 3 located in the resonant region 9; Condition 2: when an edge region 10 is provided at the connection between the connection region 8 and the resonant region 9, the width of at least one piezoelectric layer 3 located in the edge region 10 is greater than the width of the piezoelectric layer 3 located in the resonant region 9; Condition 3: the thickness of at least one piezoelectric layer 3 located in the connection region 8 is less than the thickness of the piezoelectric layer 3 located in the resonant region 9. See the following description for details.

[0035] For example, since the resonant region 9 includes two ends, each end is connected to the peripheral region 7 through a connection region 8, therefore, there are specifically two connection regions 8. Similarly, the edge region 10 may also include two. The piezoelectric layer 3 located at least once in the connection region 8 / edge region 10 can specifically refer to the piezoelectric layer 3 located in any one of the connection regions 8 / edge regions 10, or the piezoelectric layer 3 located in both connection regions 8 / edge regions 10. Optionally, the edge region 10 may also be one or non-existent.

[0036] For example, please continue reading. Figure 1 as well as Figure 2The electrode layer may specifically include a bottom electrode 2 located at the bottom of the piezoelectric layer 3, and a top electrode 4 located on the piezoelectric layer 3, or the structure of the top electrode 4 may be axially symmetrical (e.g., the combined structure of the top electrode 4 and the bottom electrode 2 may be symmetrical along the axis A3). Specifically, both the top electrode 4 and the bottom electrode 2 include a busbar 5 and an electrode finger 6. The area where the electrode finger 6 of the top electrode 4 and the bottom electrode 2 overlaps with the piezoelectric layer 3 is the resonant region 9. The length extension direction of the busbar 5 can be defined as the x-direction (i.e., the first direction), the length extension direction of the electrode finger 6 can be defined as the y-direction, and the thickness direction of the piezoelectric layer 3 can be defined as the z-direction.

[0037] For example, please refer to Figure 3 As shown Figure 1 The corresponding top view, according to Figure 3 The midsection lines A1, A2, A3, A4, and A5 can be used to obtain the following: Figure 4 The cross-sectional views corresponding to each section line are shown below. Specifically, as can be seen from the above, the connection region 8 includes two units, which can be referred to as the first connection unit 801 and the second connection unit 802, respectively; the edge region 10 can also include two units, which can be referred to as the first edge unit 101 and the second edge unit 102, respectively; the first end of the resonant region 9 is connected to the outer region 7 through the first connection unit 801, and the second end of the resonant region 9 is connected to the outer region 7 through the second connection unit 802. Among them, section line A1 is specifically located in the first connection unit 801, section line A2 is specifically located in the first edge unit 101; section line A3 is specifically located in the middle of the resonator region, i.e., the central region; section line A4 is specifically located in the second edge unit 102; and section line A5 is specifically located in the second connection unit 802.

[0038] Please continue reading. Figure 1 The piezoelectric layer 3 includes a first piezoelectric region 301, a second piezoelectric region 302, and a third piezoelectric region 303 connected sequentially along the y-direction; the first piezoelectric region 301 corresponds to the first connecting unit 801; the second piezoelectric region 302 corresponds to the resonant region 9; and the third piezoelectric region 303 corresponds to the second connecting unit 802. Specifically, the width of each region can refer to its length along the x-direction, and the thickness of each region can refer to its length along the z-direction. The width of the piezoelectric layer 3 located in the central region of the resonant region 9, i.e., the width of the resonant central region 13 (or the width of the central region of the second piezoelectric region 302), is W1, and the thickness is h1. The dimensions of the first piezoelectric region 301 and the second piezoelectric region 302 are equivalent, with a width of W3 and a thickness of h3. The dimensions of the piezoelectric layer 3 in the first edge unit 101 can be equivalent to the dimensions of the piezoelectric layer 3 in the second edge unit 102, with a width of W2 and a thickness of h2 (in other embodiments, the dimensions of the first and second edge units can also be different, as detailed below). Figure 1 and Figure 4 It can be seen that W2 > W1 > W3; h1 = h2 = h3.

[0039] In one exemplary embodiment, the bottom electrode 2 and the top electrode 4 are made of conductive materials; the conductive materials include one or more combinations of copper, aluminum, gold, silver, tungsten, platinum, nickel, chromium, molybdenum, titanium, graphene, copper-aluminum alloy, aluminum-silicon alloy, doped silicon, silicon carbide, and gallium nitride.

[0040] In one exemplary embodiment, the material of the piezoelectric layer 3 located in the resonant region 9 is one of lithium tantalate, lithium niobate, aluminum nitride, aluminum nitride-doped, lead zirconate titanate, or lead magnesium niobate-lead titanate. In one exemplary embodiment, at least one of the absolute values ​​of the piezoelectric coefficients e33, e34, and e35 of the piezoelectric layer 3 located in the resonant region 9 along the width direction of the resonant region 9 is not less than 1 C / m. 2 Alternatively, the sum of the absolute values ​​of the piezoelectric coefficients e31, e33, and e35 is not less than 1 C / m. 2 .

[0041] In one exemplary embodiment, the target mode of the acoustic resonator is a higher-order mode of the horizontal shear mode, vertical shear mode, or thickness stretching mode; the higher-order mode is a mode with an order greater than or equal to 1.

[0042] In one exemplary embodiment, the length L1 of the resonant region 9 is greater than 10 times the width W1 of the piezoelectric layer 3 located in the central region of the resonant region 9. Optionally, L1 can be 11W1, 12W1, 13W1, 14W1, etc.

[0043] In another exemplary embodiment, the length L1 of the resonant region 9 is less than 100 times the width W1 of the piezoelectric layer 3 located in the central region of the resonant region 9. Optionally, L1 can be 99W1, 98W1, 97W1, 96W1, etc., to improve the performance of the resonant device. Furthermore, L1 can also be less than 40W1 to further improve device performance.

[0044] To better illustrate the beneficial effects of this application, the following comparative figures are presented: For example, a pair of proportions is provided, the structure of which is as follows: Figure 5 The structure shown includes, from bottom to top, a supporting substrate 1, a dielectric layer 11, a bottom electrode 2, a piezoelectric layer 3, and a top electrode 4; specifically, it includes multiple resonant units arranged at intervals along a first direction, each resonant unit including a bottom electrode 2, a piezoelectric layer 3, and a top electrode 4, with a width of We. Specifically, the supporting substrate 1 and the dielectric layer 11 form a cavity 12, allowing the multiple resonant units to be suspended on the supporting substrate 1. Please refer to [link to relevant documentation]. Figure 6Both the top electrode 4 and the bottom electrode 2 include a plurality of electrode fingers 6 arranged at intervals along the first direction, and the busbar 5 of the top electrode 4 is located in the peripheral area 7.

[0045] Specifically, a set of comparative examples is provided, the structure of which is... Figure 5 The structure shown is as follows. The top electrode 4 and bottom electrode 2 are both made of aluminum, with a thickness of 50 nm. The piezoelectric layer 3 is made of X-cut lithium niobate, with a thickness of 400 nm and a width of 400 nm. In-plane orientation refers to the angle between the width direction and the crystal's Y-axis; the width direction is... Figure 5 In the x-direction, the in-plane orientation differs for each comparative example. Through relevant calculations, we can obtain, as follows: Figure 7 The figures show the electromechanical coupling coefficients of the various comparative models as a function of in-plane orientation. It can be seen that for higher-order vertical shear modes, the electromechanical coupling coefficient approaches its maximum value, reaching 69%, when the in-plane orientation is 119°. At this point, the electromechanical coupling coefficient of higher-order horizontal shear modes is almost zero. For higher-order horizontal shear modes, the electromechanical coupling coefficient approaches its maximum value, reaching 100%, when the in-plane orientation is 38°. At this point, the electromechanical coupling coefficient of higher-order vertical shear modes is almost zero.

[0046] Another set of comparative examples is provided, the structure of which is... Figure 5 The structure is shown. The top electrode 4 and bottom electrode 2 are made of aluminum, each with a thickness of 50 nm. The piezoelectric layer 3 is made of X-cut lithium niobate, with an in-plane orientation of 119°, a thickness of 400 nm, and a width of 400 nm. The lengths of the resonant regions 9 in each comparative example are different (specifically, the lengths of the resonant regions 9 include 4W4, 6W4, 8W4, 10W4, 12W4, 14W4, and 16W4), where W4 represents the width of the piezoelectric layer 3 in each resonant unit. Through relevant calculations, the following can be obtained: Figure 8 As shown in the admittance curve, it can be seen that since the length direction of the resonant region 9 can also be used as the width direction of the higher-order horizontal mode, the resonance peak circled in the dashed circle is caused by the higher-order horizontal shearing mode; when the length of the resonant region 9 exceeds 12W4, the resonance peak generated by the higher-order horizontal shearing mode can be ignored.

[0047] Another pair of proportions is provided, the structure of which is: Figure 5 The structure shown is as follows. The top electrode 4 and bottom electrode 2 are made of aluminum, each with a thickness of 50 nm. The piezoelectric layer 3 is made of X-cut lithium niobate, with an in-plane orientation of 119°, a thickness of 400 nm, and a width of 400 nm. The resonant region 9 has a length of 16W4, and the connecting unit (i.e....) Figure 6 The length of the dashed box is 2W4. Through relevant calculations, we can obtain the following... Figure 9 As shown in the admittance / conductance curves, there are a large number of transverse higher-order modes between the resonant frequency and the anti-resonant frequency.

[0048] As can be seen from the above analysis, the dimensional relationship between the length and width of the resonant region 9 affects the device performance.

[0049] It is understandable that the edge region 10 can specifically refer to the area located at the connection between the resonant region 9 and / or the connecting region 8, and the region with a width W2 greater than the width W1 of the resonant center region 13 (e.g., Figure 1 (as shown in the structure), therefore, the device may or may not have an edge region 10 (i.e., as shown in the structure). Figure 10 The length of the edge region 10 (i.e., the length along the y direction) ranges from (0, 0.2L1], where (0, 0.2L1] means that the boundary value 0 is not included, but the boundary value 0.2L1 is included. Specifically, the length of the edge region 10 (any edge unit, such as the first edge unit 101 or the second edge unit 102) can be 0.05L1, 0.1L1, 0.15L1, or 0.2L1.

[0050] For example, the electrode layer may not completely cover the piezoelectric layer 3 located in the edge region 10, as can be explained in detail below: In another exemplary embodiment, the width of the edge region 10 is greater than the width of the central region of the resonant region 9, and the width of the electrode layer in the edge region 10 is equal to the width of the central region of the resonant region 9. That is, as... Figure 3 , and the following text Figure 11 , Figures 14-19 , Figures 31-34 The structure shown.

[0051] In another exemplary embodiment, the material of the piezoelectric layer 3 located in the edge region 10 is the same as the material of the piezoelectric layer 3 located in the resonant region 9. That is, as described below. Figure 11 , Figures 14-23 , Figures 31-35 The structure shown.

[0052] Specifically, a set of examples is provided, with the following structure: Figure 11 The structure shown is arranged as follows: Figure 3Cutting along the five cross-sections shown yields at least Structure 1 and Structure 2. Structure 1 is the cross-section corresponding to cross-sections A2 / A4 (i.e., the cross-section corresponding to edge region 10); Structure 2 is the cross-section corresponding to cross-section A3 (i.e., the cross-section corresponding to resonant center region 13). In this set of examples, the top electrode 4 and bottom electrode 2 are made of aluminum, each with a thickness of 50 nm. The piezoelectric layer 3 is made of X-cut lithium niobate, with an in-plane orientation of 119° and a thickness of 400 nm. The width (i.e., W1) of the central region of the second piezoelectric region 302 is 400–800 nm. For Structure 1, the width of both the top electrode 4 and bottom electrode 2 is 400 nm. For Structure 2, the width of both the top electrode 4 and bottom electrode 2 is consistent with the width of the central region (i.e., W1) of the second piezoelectric region 302. The W1 varies in each example; through relevant calculations, the following can be obtained: Figure 12 The curves showing the resonant frequency of the acoustic resonator relative to the width of piezoelectric layer 3 are shown. It can be seen that the resonant frequency of both structures decreases as the width of piezoelectric layer 3 (specifically the widths of the first and second piezoelectric regions) increases; moreover, the change in the width of the electrode layer has a relatively small impact, which is quite different from the traditional SAW resonator.

[0053] Specifically, another set of examples is provided, including Comparative Example 1 and Example 1, both of which have the following structure. Figure 11 The structure shown has top electrode 4 and bottom electrode 2 made of aluminum, each with a thickness of 50 nm. The second piezoelectric region 302 is made of X-cut lithium niobate with an in-plane orientation of 119°, a thickness of 400 nm, and a width of 400 nm. The length of the resonant region 9 is 80 W1, and the length of the connection region 8 is 2 W1. However, the width of the edge region 10 in Comparative Example 1 is equal to W1, while the width of the edge region 10 in Example 1 is 1.4 W1, and the length is 2 W1. Through relevant calculations, the following can be obtained: Figure 13 As shown in the admittance / conductance curves, it can be seen that the widened edge region 10 significantly suppresses the transverse higher-order modes, but requires a longer length of the resonant region 9.

[0054] In one exemplary embodiment, optionally, the shape of the edge region 10 in a top-view perspective is rectangular (e.g., ...). Figure 11 The structure shown); optionally, the shape of the edge region 10 in the top view is triangular (e.g., the structure shown). Figure 14 and Figure 15 The structure shown); optionally, the shape of the edge region 10 in the top view is elliptical (e.g., the structure shown). Figure 16 (The structure shown). In practice, the shape of the edge region 10 from a top-down view may not be limited to the example above, depending on the actual needs.

[0055] In another exemplary embodiment, the edge region 10 is provided at one of the two ends of the resonant region 9. Optionally, the resonant region 9 may be provided with a first edge unit 101 (e.g., Figure 17 (The structure shown). Alternatively, the resonant region 9 may have a second edge unit 102.

[0056] In another exemplary embodiment, the edge regions 10 are provided at corresponding locations at both ends of the resonant region 9 (e.g., Figure 11 The structure shown.

[0057] It should be understood that the edge region 10 can be located in the resonant region 9 or in the connection region 8 (e.g., Figure 18 (The structure shown). Alternatively, a portion of the edge region 10 could be located in the connection region 8, and another portion in the resonant region 9 (as shown). Figure 19 (as shown in the structure); but regardless of the scheme, the edge region 10 is located at the corresponding end of the resonant region 9.

[0058] In another exemplary embodiment, the electrode layer may completely cover the piezoelectric layer 3 of the edge region 10, see [link to relevant documentation]. Figures 20-23 Regardless of whether the shape of the edge region 10 is rectangular, polygonal, or otherwise, or the location of the edge region 10 (such as the resonant region 9, the connection region 8, or a combination of both), or the number (such as one edge region 10 or two), as long as it is an edge region 10, its surface can fully cover the electrode layer.

[0059] Specifically, Example 2 is provided, whose structure is as follows: Figure 23 The structure shown has top electrode 4 and bottom electrode 2 made of aluminum, each with a thickness of 50 nm. The second piezoelectric region 302 is made of X-cut lithium niobate with an in-plane orientation of 119°, a thickness of 400 nm, and a width of 400 nm. The resonant region 9 has a length of 16 W1, the connection region 8 has a length of 2 W1, and a width of 0.6 W1. The first piezoelectric region 301, the third piezoelectric region 303, and the peripheral region 7 are all made of silicon oxide. That is, the piezoelectric layer 3 has the same material in the connection region 8 and the peripheral region 7, but a different material in the resonant region 9. The edge region 10 has a width of 1.08 W1 and a length of 0.4 W1. Through relevant calculations, the following can be obtained: Figure 24 As shown in the admittance curve, it can be seen that a good effect of suppressing transverse high-order modes can also be achieved. Since the piezoelectric layer 3 and the electrode layer have the same shape, they can be realized based on a photomask during the molding process, which has the effect of simpler processing.

[0060] The above is a description of the edge region 10. The following is a brief description of the layer structure of the acoustic resonator: In an exemplary embodiment, the layer structure of the acoustic resonator can be a supporting substrate 1 + bottom electrode 2 + piezoelectric layer 3 + top electrode 4. The supporting substrate 1 has a groove structure to form a cavity 12, and the bottom electrode 2 can be directly connected to the edge of the groove structure.

[0061] In another exemplary embodiment, the layer structure of the acoustic resonator can be a supporting substrate 1 + bottom electrode 2 + piezoelectric layer 3 + top electrode 4. For details, please refer to [link to relevant documentation]. Figure 25 and Figure 26 The peripheral region 7 can be an electrode material. Specifically, the material of the peripheral region 7 below the top electrode 4 is the same as the material of the top electrode 4, and the material of the peripheral region 7 above the bottom electrode 2 is the same as the material of the bottom electrode 2. Corresponding conductive elements are provided in the peripheral region 7 to form a cavity 12, a suspended connection region 8, and a resonant region 9 with the supporting substrate 1.

[0062] In another exemplary implementation, please refer to Figure 27 The layer structure of the acoustic resonator can be a supporting substrate 1 + dielectric layer 11 + bottom electrode 2 + piezoelectric layer 3 + top electrode 4, that is, the outer layer and the supporting substrate 1 are connected through the dielectric layer 11. For example, the dielectric layer 11 is a single-layer material or a multi-layer material; the material of the dielectric layer 11 includes one or more of silicon oxide, silicon nitride, polycrystalline silicon, amorphous silicon, aluminum oxide, and aluminum nitride; the dielectric layer 11 is a sacrificial layer, temperature compensation layer, heat dissipation layer, trap-rich layer, bonding layer, low sound velocity layer, and dispersion control layer.

[0063] Optionally, the piezoelectric layer 3 located in the outer region 7 can be, for example, Figure 2 The ring structure shown has a hollow central region, with the connecting region 8 and the resonant region 9 located within this hollow region. Optionally, the piezoelectric layer 3 located in the outer region 7 can also be positioned only below the busbar 5 of the top electrode 4 and above the busbar 5 of the bottom electrode 2. No restrictions are imposed here.

[0064] It should be noted that the materials of the peripheral region 7, the connecting region 8, and the piezoelectric layer 3 located in the resonant region 9 are different, or at least two regions are made of the same material. The region of the piezoelectric layer 3 located in the peripheral region 7 can be referred to as the fourth piezoelectric region; the first piezoelectric region 301 and the third piezoelectric region 303 are made of the same material, while the second piezoelectric region 302 is made of a piezoelectric material. Optionally, the materials of the first piezoelectric region 301, the second piezoelectric region 302, and the fourth piezoelectric region are different (e.g., ...). Figure 26 , and the following text Figures 34-36 , Figure 41 (The structure shown); optionally, the materials of the first piezoelectric region 301 and the second piezoelectric region 302 are different, and the materials of the first piezoelectric region 301 and the fourth piezoelectric region are the same (e.g., the structure shown). Figure 23 , Figure 28 , and the following text Figure 33 (The structure shown); optionally, the first piezoelectric region 301 and the fourth piezoelectric region are made of different materials, and the first piezoelectric region 301 and the second piezoelectric region 302 are made of the same material (e.g., the structure shown). Figure 25 (The structure shown); optionally, the first piezoelectric region 301 and the second piezoelectric region 302 are made of different materials, and the second piezoelectric region 302 is made of the same material as the fourth piezoelectric region (e.g., the structure shown). Figure 1 , Figure 32 and Figure 27 (Structure shown); optionally, the first piezoelectric region 301, the second piezoelectric region 302, and the fourth piezoelectric region are made of the same material (e.g., Figure 10 , Figure 11 , Figures 14-22 , and the following text Figure 31 , Figure 37 and Figure 38 The structure shown.

[0065] In one exemplary embodiment, the material of the peripheral region 7 is a conductive material (such as...). Figure 25 and Figure 26 The structure shown.

[0066] Specifically, another set of examples is provided, with the following structure: Figure 10 The structure shown has top electrode 4 and bottom electrode 2 made of aluminum, each with a thickness of 50 nm. The second piezoelectric region 302 is made of X-cut lithium niobate with an in-plane orientation of 119°, a thickness of 400 nm, and a width of 400 nm. The resonant region 9 has a length of 16 W1, the connection region 8 has a length of 2 W1, and the width of the connection region 8 ranges from 0.2 to 1.2 W1 (i.e., 0.2 W1, 0.4 W1, 0.6 W1, 0.8 W1, 1 W1, and 1.2 W1, respectively). The width of the connection region 8 varies in each example. Through relevant calculations, the following can be obtained: Figure 29 The admittance curve is shown.

[0067] Provide another set of instances, whose structure is as follows: Figure 28 The structure shown has top electrode 4 and bottom electrode 2 made of aluminum, each with a thickness of 50 nm. The second piezoelectric region 302 is made of X-cut lithium niobate with an in-plane orientation of 119°, a thickness of 400 nm, and a width of 400 nm. The resonant region 9 has a length of 16 W1, the connection region 8 has a length of 2 W1, and the width of the connection region 8 is 0.2–1.2 W1 (i.e., 0.2 W1, 0.4 W1, 0.6 W1, 0.8 W1, 1 W1, and 1.2 W1, respectively). The first piezoelectric region 301 (located in the connection region 8), the third piezoelectric region 303 (located in the connection region 8), and the fourth piezoelectric region (located in the peripheral region 7) are all made of silicon oxide. The width of the connection region 8 varies in each example. Through relevant calculations, the following can be obtained: Figure 30 The admittance curve is shown. (Comparison) Figure 29 and Figure 30 It can be seen that after replacing the piezoelectric material of the piezoelectric layer 3 located in the connection region 8 with silicon oxide, the lateral higher-order modes of the silicon oxide device are weaker when the width of the connection region 8 is the same. This means that when the material of the piezoelectric layer 3 located in the connection region 8 is different from the material of the piezoelectric layer 3 located in the resonant region 9, a wider connection region 8 can be used, which can increase the structural strength.

[0068] The following will describe in detail the distribution of dimensions (such as width and thickness) of each layer: In one exemplary embodiment, the width W2 of the piezoelectric layer 3 located in the edge region 10 is greater than the width W1 of the piezoelectric layer 3 located in the central region of the resonant region 9, and the width W3 of the piezoelectric layer 3 located in the connection region 8 is less than the width W1 of the piezoelectric layer 3 located in the central region of the resonant region 9. That is, W2 > W1 > W3, i.e. Figure 1 , Figures 20-23 , Figure 26 , Figures 31-36 , and the following text Figure 41 The structure shown.

[0069] Specifically, another set of examples is provided, including Comparative Example 2, Example 3, and Example 4, wherein the structure of Comparative Example 2 is as follows: Figure 10 The structure shown; the structure of Example 3 is as follows Figure 28 The structure shown; the structure of Example 4 is as follows Figure 33 The structure shown is as follows: the top electrode 4 and bottom electrode 2 are made of aluminum, each with a thickness of 50 nm; the second piezoelectric region 302 is made of X-cut lithium niobate, with an in-plane orientation of 119°, a thickness of 400 nm, and a width of 400 nm; the resonant region 9 has a length of 16 W1, the connection region 8 has a length of 2 W1, and the connection region 8 has a width of 0.6 W1; and the first piezoelectric region 301 (located in the connection region 8), the third piezoelectric region 303 (located in the connection region 8), and the fourth piezoelectric region (located in the peripheral region 7) are all made of silicon oxide; the edge region 10 of Comparative Example 2 and Example 4 has a width of 1.11 W1 and a length of 0.4 W1. Through relevant calculations, the following can be obtained: Figure 36 As shown in the admittance / conductance curves, it can be seen that by combining the narrowed connection region 8 and the widened edge region 10, the transverse higher-order modes can be suppressed to the greatest extent, and the length of the resonant region 9 is only 16W1.

[0070] For common surface acoustic wave (SAW) devices, the length of the resonant region 9, which is also the aperture length, is typically 15 to 30 times the wavelength. The wavelength is the same as the electrode period; with a metal duty cycle of 0.5, the wavelength is four times the electrode width. Therefore, the aperture length is 60 to 120 times the electrode width. When the aperture shrinks to less than 10 times the wavelength, not only does the diffraction effect increase and losses rise, but the transverse higher-order modes also become so strong that they are difficult to suppress. In this embodiment, the length of the resonant region 9 is only 16W1, demonstrating a miniaturization advantage unmatched by traditional devices.

[0071] In another exemplary embodiment, the width W2 of the piezoelectric layer 3 located in the edge region 10 is greater than the width W1 of the piezoelectric layer 3 located in the central region of the resonant region 9, and the width W3 of the piezoelectric layer 3 located in the connection region 8 is less than the width W1 of the piezoelectric layer 3 located in the central region of the resonant region 9. The thickness h3 of the piezoelectric layer 3 located in the connection region 8 is less than the thickness h1 of the piezoelectric layer 3 located in the central region of the resonant region 9. That is, W2 > W1 > W3, and h1 > h3.

[0072] In another exemplary embodiment, the width W2 of the piezoelectric layer 3 located in the edge region 10 is greater than the width W1 of the piezoelectric layer 3 located in the central region of the resonant region 9, and the thickness h3 of the piezoelectric layer 3 located in the connection region 8 is less than the thickness h1 of the piezoelectric layer 3 located in the central region of the resonant region 9; that is, W2 > W1, and h1 > h3.

[0073] Since h1 > h3, specifically, the surface of the piezoelectric layer 3 in contact with the bottom electrode 2 can be flat, and the surface of the piezoelectric layer 3 in contact with the top electrode 4 can be flat (as shown in structure 38). Alternatively, the surface of the piezoelectric layer 3 in contact with the bottom electrode 2 can be uneven, and the surface of the piezoelectric layer 3 in contact with the top electrode 4 can be uneven (as shown in structure 37). In other embodiments, any one of the above-mentioned contact surfaces can be flat, and the other contact surface can be uneven, which is not limited here.

[0074] Optionally, the material of the piezoelectric layer 3 located in the connection region 8 is the same as the material of the piezoelectric layer 3 located in the resonant region 9, that is, the materials of the first piezoelectric region 301, the second piezoelectric region 302 and the third piezoelectric region 303 are the same, which may include the following feasible solutions.

[0075] In another exemplary embodiment, the width W3 of the piezoelectric layer 3 located in the connection region 8 is smaller than the width W1 of the piezoelectric layer 3 located in the central region of the resonant region 9. The width W3 of the connection region 8 satisfies [0.1W1, 0.6W1] (e.g. Figure 10 , Figures 20-22 , Figure 31 (The structure shown); W1 represents the width of the piezoelectric layer 3 located in the central region of the resonant region 9.

[0076] Specifically, another example 3 is provided, whose structure is as follows: Figure 10 The structure shown has top electrode 4 and bottom electrode 2 made of aluminum, each with a thickness of 50 nm. The second piezoelectric region 302 is made of X-cut lithium niobate with an in-plane orientation of 119°, a thickness of 400 nm, and a width of 400 nm. The resonant region 9 has a length of 80 W1, the connection region 8 has a length of 2 W1, and the connection region 8 has a width of 0.2 W1. Through relevant calculations, the following can be obtained: Figure 39 As shown in the admittance curve, it can be seen that by reducing the width of the connection region 8, the lateral higher-order modes can be significantly weakened.

[0077] In another exemplary embodiment, the thickness h3 of the piezoelectric layer 3 located in the connection region 8 satisfies [0.1h1, 0.6h1] (e.g. Figure 37 and 38 (The structure shown); where h1 represents the thickness of the piezoelectric layer 3 located in the central region of the resonant region 9.

[0078] Optionally, the material of the piezoelectric layer 3 located in the connection region 8 is different from the material of the piezoelectric layer 3 located in the resonant region 9. That is, the materials of the first piezoelectric region 301 and the third piezoelectric region 303 are the same, and the materials of the first piezoelectric region 301 and the second piezoelectric region 302 are different. The following feasible solutions may be included.

[0079] In another exemplary embodiment, the width W3 of the piezoelectric layer 3 located in the connection region 8 is smaller than the width W1 of the piezoelectric layer 3 located in the central region of the resonant region 9, and the width W3 of the connection region 8 satisfies [0.1W1, W1) (e.g. Figure 26 and Figure 27 (The structure shown); W1 represents the width of the piezoelectric layer 3 located in the central region of the resonant region 9.

[0080] In another exemplary embodiment, the thickness of the piezoelectric layer 3 located in the connection region 8 is less than the thickness of the piezoelectric layer 3 located in the resonant region 9, and the thickness of the connection region 8 satisfies [0.1h1, h1) (e.g. Figure 27 (The structure shown); where h1 represents the thickness of the piezoelectric layer 3 located in the central region of the resonant region 9.

[0081] In another exemplary implementation, please refer to Figure 40 and Figure 41The acoustic resonator may include N resonant regions 9 and 2N connection regions 8; where N is an integer greater than or equal to 1; one end of each resonant region 9 is connected to the peripheral region 7 through one connection region 8, and the other end is connected to the peripheral region 7 through another connection region 8; the multiple resonant regions 9 are arranged at intervals along a first direction; the first direction is the length extension direction of the busbar 5 of the electrode layer; correspondingly, the bottom electrode 2 and the top electrode 4 each include multiple electrode fingers 6 arranged at intervals along the first direction, and the piezoelectric layer 3 also includes multiple sub-piezoelectric layers 3 arranged at intervals along the first direction; each sub-piezoelectric layer 3 includes a first piezoelectric region 301, a second piezoelectric region 302, and a third piezoelectric region 303; each resonant region 9 corresponds to one bottom electrode 2 and one electrode finger 6, one electrode finger 6 of the top electrode 4, and one sub-piezoelectric layer 3, in order to meet the impedance matching requirements of the device.

[0082] This embodiment of the application, by taking advantage of the characteristic that higher-order mode vibrations are concentrated at the top and bottom, sets a narrowed connection region, which can enhance the reflection at the boundary of the resonant region, thereby weakening the transverse higher-order modes. When the material of the connection region is different from that of the resonant region, the degree of narrowing of the connection region can be reduced, enhancing structural stability. Furthermore, based on the characteristic that the frequency of higher-order modes is strongly correlated with the piezoelectric film, setting a widened piezoelectric film in the edge region can change the distribution of transverse higher-order modes, thereby suppressing transverse higher-order modes while reducing the length of the strip-shaped resonant region. This achieves a small-volume, high-frequency, large-bandwidth, structurally robust, and clutter-suppressed acoustic resonator.

[0083] On the other hand, this application also discloses a communication device that includes at least the aforementioned acoustic resonator; the communication device includes any one of a filter, a duplexer, a multiplexer, and a filter module.

[0084] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An acoustic resonator, characterized in that, At least including: Support substrate; The upper structure includes a stacked electrode layer and a piezoelectric layer. The upper structure can be divided into a peripheral region, a connection region, and a resonant region from the outside to the inside. The resonant region is located in the hollow area of ​​the peripheral region and is connected to the peripheral region through the connection region. The connection region and the resonant region are suspended on the supporting substrate. Wherein, the material of the piezoelectric layer located in the resonant region is a piezoelectric material; and at least one piezoelectric layer located in the connection region has a width smaller than the width of the piezoelectric layer located in the resonant region, and / or, when an edge region is provided at the connection between the connection region and the resonant region, at least one piezoelectric layer located in the edge region has a width larger than the width of the piezoelectric layer located in the resonant region, and / or, at least one piezoelectric layer located in the connection region has a thickness smaller than the thickness of the piezoelectric layer located in the resonant region.

2. The acoustic resonator according to claim 1, characterized in that, The width of the edge region is greater than the width of the central region of the resonant region; At least one of the two ends of the resonant region is provided with the edge region at the corresponding end, and / or part or all of the edge region is located at the end of the connection region near the resonant region.

3. The acoustic resonator according to claim 2, characterized in that, The shape of the edge area from a top-down perspective is one of a rectangle, triangle, polygon, or ellipse.

4. The acoustic resonator according to claim 2, characterized in that, The material of the piezoelectric layer located in the edge region is the same as the material of the piezoelectric layer located in the resonant region.

5. The acoustic resonator according to claim 1, characterized in that, The materials of the peripheral region, the connecting region, and the piezoelectric layer located in the resonant region are different, or at least two regions are made of the same material.

6. The acoustic resonator according to claim 1, characterized in that, When the width of the piezoelectric layer in the connection region is smaller than the width of the piezoelectric layer in the resonant region, and the material of the piezoelectric layer in the connection region is the same as the material of the piezoelectric layer in the resonant region, the width of the connection region satisfies [0.1W1, 0.6W1]; where W1 represents the width of the piezoelectric layer in the central region of the resonant region.

7. The acoustic resonator according to claim 1, characterized in that, When the width of the piezoelectric layer in the connection region is smaller than the width of the piezoelectric layer in the resonant region, and the material of the piezoelectric layer in the connection region is different from that of the piezoelectric layer in the resonant region, the width of the connection region satisfies [0.1W1, W1); where W1 represents the width of the piezoelectric layer in the central region of the resonant region.

8. The acoustic resonator according to claim 1, characterized in that, When the material of the piezoelectric layer located in the connection region is the same as the material of the piezoelectric layer located in the resonance region, the thickness of the piezoelectric layer located in the connection region satisfies [0.1h1, 0.6h1]; where h1 represents the thickness of the piezoelectric layer located in the central region of the resonance region.

9. The acoustic resonator according to claim 1, characterized in that, When the thickness of the piezoelectric layer in the connection region is less than the thickness of the piezoelectric layer in the resonant region, and the material of the piezoelectric layer in the connection region is different from the material of the piezoelectric layer in the resonant region, the thickness of the connection region satisfies [0.1h1, h1); where h1 represents the thickness of the piezoelectric layer in the central region of the resonant region.

10. The acoustic resonator according to claim 1, characterized in that, The width of the piezoelectric layer located in the edge region is greater than the width of the piezoelectric layer located in the center region of the resonant region, and the width of the piezoelectric layer located in the connection region is less than the width of the piezoelectric layer located in the center region of the resonant region.

11. The acoustic resonator according to claim 1, characterized in that, The width of the piezoelectric layer located in the edge region is greater than the width of the piezoelectric layer located in the center region of the resonant region, and the thickness of the piezoelectric layer located in the connection region is less than the thickness of the piezoelectric layer located in the center region of the resonant region.

12. The acoustic resonator according to claim 10, characterized in that, The thickness of the piezoelectric layer located in the connection region is less than the thickness of the piezoelectric layer located in the central region of the resonant region.

13. The acoustic resonator according to any one of claims 1-12, characterized in that, The length of the resonant region is greater than 10 times the width of the piezoelectric layer located in the resonant region.

14. The acoustic resonator according to claim 13, characterized in that, The length of the resonant region is less than 100 times the width of the piezoelectric layer located in the resonant region.

15. The acoustic resonator according to any one of claims 1-12, characterized in that, It includes N resonant regions and 2N connection regions; where N is an integer greater than or equal to 1. One end of each of the resonant regions is connected to the peripheral region through one of the connection regions, and the other end is connected to the peripheral region through another connection region; The plurality of resonant regions are arranged at intervals along a first direction; the first direction is the length extension direction of the busbar of the electrode layer.

16. The acoustic resonator according to any one of claims 1-12, characterized in that, The material of the outer perimeter area is a conductive material.

17. The acoustic resonator according to any one of claims 1-12, characterized in that, It also includes a dielectric layer; The outer layer is connected to the supporting substrate through the dielectric layer; The dielectric layer may be a single-layer material or a multi-layer material; The material of the dielectric layer includes one or more of silicon oxide, silicon nitride, polycrystalline silicon, amorphous silicon, aluminum oxide, and aluminum nitride; The dielectric layer is one or more of the following: sacrificial layer, temperature compensation layer, heat dissipation layer, trap-rich layer, bonding layer, low-velocity layer, and dispersion modulation layer.

18. The acoustic resonator according to any one of claims 1-12, characterized in that, The piezoelectric layer located in the resonant region is made of one of lithium tantalate, lithium niobate, aluminum nitride, aluminum nitride-doped aluminum nitride, lead zirconate titanate, or lead magnesium niobate-lead titanate. At least one of the absolute values ​​of the piezoelectric coefficients e33, e34, and e35 of the piezoelectric layer located in the resonant region along the width direction of the resonant region is not less than 1 C / m. 2 Alternatively, the sum of the absolute values ​​of the piezoelectric coefficients e31, e33, and e35 is not less than 1 C / m. 2 .

19. The acoustic resonator according to any one of claims 1-12, characterized in that, The target modes of the acoustic resonator are higher-order modes of the horizontal shear mode, vertical shear mode, and thickness expansion mode; the higher-order modes are modes with an order greater than or equal to 1.

20. A communication device, characterized in that, It includes at least any one of the acoustic resonators of claims 1-19; The communication device includes any one of a filter, a duplexer, a multiplexer, and a filter module.

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