Acoustic wave device structure with temperature compensation characteristics, filter, and electronic device

Abstract

The present disclosure provides an acoustic wave device structure, a filter and an electronic device with temperature compensation characteristics. The acoustic wave device structure comprises a piezoelectric layer, a temperature compensation layer and a resonant electrode layer. The temperature compensation layer is arranged corresponding to at least one surface of the piezoelectric layer, and is used to provide a temperature compensation effect for the piezoelectric layer. The resonant electrode layer comprises a filling site, which exposes the surface of the piezoelectric layer, and is used to fill or inject a planarization material to form a planarization layer which is flush with a surface of the resonant electrode layer. The planarization layer which is flush with the surface of the resonant electrode layer can effectively reduce the defect problem of the interface of the temperature compensation layer caused by process defects, and can also move the parasitic spurious mode near the resonant frequency away from the main resonant peak through the planarization layer, thereby improving the overall effective coupling coefficient of the device and reducing the sensitivity of the temperature compensation layer to the frequency.

Description

Technical Field

[0001] This disclosure relates to the field of filter technology, and in particular to an acoustic device structure, filter, and electronic device with temperature compensation characteristics. Background Technology

[0002] Acoustic filters can be used in high-frequency circuits, for example, as bandpass filters. An acoustic filter is composed of several acoustic resonators. Acoustic resonators are generally classified into surface acoustic wave (SAW) devices and bulk acoustic wave (BAW) devices according to their vibration modes. SAW devices can use interdigital transducers (IDTs) to convert electrical energy into acoustic energy, or vice versa. IDTs use a piezoelectric substrate and two opposing buses at two different potentials, along with two sets of electrodes connected to the buses. Due to the inverse piezoelectric effect, the electric field between the two consecutive electrodes at different potentials provides the sound source. Conversely, if the transducer receives the incident wave, charge is generated in the electrodes due to the piezoelectric effect. By placing the transducer between two reflective grids, the energy is confined within the transducer, resulting in a high-quality resonator.

[0003] SAW devices mainly include conventional SAW (Normal-SAW), bonded-wafer SAW, buried temperature-compensated SAW (Buried TC-SAW), and SAW with piezoelectric on-insulator material on an insulating substrate (POI SAW). Among them, buried TC-SAW is widely used in mobile communication equipment due to its high TCF and Q value, relatively simple fabrication process, and moderate cost. Generally, the buried TC-SAW structure can use LiNbO3 or LiTaO3 as the piezoelectric substrate, grow metal electrodes on the surface, and then lay a thick temperature compensation layer (such as SiO2, or SiO2 doped with other elements) to achieve the temperature compensation effect. However, buried TC-SAW also has problems such as the generation of clutter modes near the main resonant mode, poor film quality yield of the temperature compensation layer, and large thickness errors, which have a significant impact on the performance of the device structure itself. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address at least one of the aforementioned technical problems existing in existing acoustic wave device structures with temperature compensation layers, such as Buried TC-SAW devices, this disclosure provides an acoustic wave device structure, filter, and electronic device with temperature compensation characteristics.

[0006] (II) Technical Solution

[0007] The first aspect of this disclosure provides an acoustic wave device structure with temperature compensation characteristics, comprising a piezoelectric layer, a temperature compensation layer, and a resonant electrode layer. The piezoelectric layer serves as the resonant structure of the acoustic wave device structure; the temperature compensation layer is disposed on at least one surface of the piezoelectric layer to provide temperature compensation for the piezoelectric layer; the resonant electrode layer is disposed on the surface of the piezoelectric layer to cooperate with the piezoelectric layer to generate a resonant effect; wherein the resonant electrode layer includes filling sites that expose the surface of the piezoelectric layer for filling or injecting planarization material to form a planarization layer flush with one surface of the resonant electrode layer.

[0008] According to embodiments of this disclosure, the resonant electrode layer includes a first interdigital electrode and a second interdigital electrode. The first interdigital electrode has a first busbar and a plurality of first interdigitates connected to the first busbar; the second interdigital electrode has a second busbar and a plurality of second interdigitates connected to the second busbar, wherein the plurality of second interdigitates and the plurality of first interdigitates are parallel to each other and interlaced on the surface of the piezoelectric layer to form an interdigital effect.

[0009] According to embodiments of this disclosure, the gap formed by the first interdigital electrode and the second interdigital electrode in a parallel and interlaced structural relationship is a fill position; or the gap between the first interdigital electrode and the second interdigital electrode corresponding to the effective resonant region between the resonant electrode layer and the piezoelectric layer is a fill position.

[0010] According to an embodiment of the present disclosure, the resonant electrode layer is a planar thin-film electrode layer disposed on the surface of the piezoelectric layer, and the filling position includes at least one filling hole, which penetrates the planar thin-film electrode layer and exposes the surface of the piezoelectric layer.

[0011] According to embodiments of this disclosure, the acoustic device structure further includes a first protective layer and / or a second protective layer. The first protective layer corresponds to one surface of the piezoelectric layer and is disposed on one surface of a corresponding temperature compensation layer; the second protective layer corresponds to the other surface of the piezoelectric layer and is disposed on the flat surface formed by the resonant electrode layer and the planarization layer.

[0012] According to an embodiment of the present disclosure, the piezoelectric layer includes an electrode groove recessed on the surface of the piezoelectric layer for providing a resonant electrode layer.

[0013] According to an embodiment of this disclosure, the depth of the electrode groove is less than the thickness of the resonant electrode layer.

[0014] According to embodiments of this disclosure, the depth of the electrode groove is equal to the thickness of the resonant electrode layer, and the surface of the piezoelectric layer without electrode grooves forms a filling site.

[0015] A second aspect of this disclosure provides a filter comprising a main path, at least one parallel path, and at least one resonator. One end of the main path is connected to an input port, and the other end is connected to an output port; at least one parallel path is connected to the main path and is in parallel with the main path; at least one resonator is connected to one of the at least one parallel path, wherein at least one of the at least one resonator comprises the aforementioned acoustic device structure with temperature compensation characteristics.

[0016] A third aspect of this disclosure provides an electronic device that includes the filter described above.

[0017] (III) Beneficial Effects

[0018] This disclosure provides an acoustic wave device structure, filter, and electronic device with temperature compensation characteristics. The acoustic wave device structure with temperature compensation characteristics includes a piezoelectric layer, a temperature compensation layer, and a resonant electrode layer. The piezoelectric layer serves as the resonant structure of the acoustic wave device; the temperature compensation layer is disposed on at least one surface of the piezoelectric layer to provide temperature compensation; the resonant electrode layer is disposed on the surface of the piezoelectric layer to generate a resonant effect in conjunction with the piezoelectric layer; the resonant electrode layer includes filler sites that expose the surface of the piezoelectric layer, used to fill or inject planarization material to form a planarization layer flush with one surface of the resonant electrode layer. Through this planarization layer flush with the surface of the resonant electrode layer, the acoustic wave device structure can effectively reduce problems such as voids and gaps at the interface of the temperature compensation layer caused by process defects. Simultaneously, the planarization layer can move parasitic clutter modes near the resonant frequency away from the main resonant peak, improving the overall effective coupling coefficient of the device and reducing the sensitivity of the temperature compensation layer to the affected frequency. Attached Figure Description

[0019] Figure 1 A schematic cross-sectional view of the structural composition of a Buried TC-SAW device with structural defects is shown.

[0020] Figure 2A The schematic illustration shows a corresponding acoustic device structure according to an embodiment of the present disclosure. Figure 2G The structural composition cross-sectional view of section line AA′ shown;

[0021] Figure 2B The diagram schematically illustrates a comparison simulation of the impedance curves of an acoustic device structure according to an embodiment of the present disclosure, with SiO2 and SiN as the planarization materials.

[0022] Figure 2C The corresponding diagram is shown schematically. Figure 1 The effective coupling coefficient k of the Buried TC-SAW device structure with structural defects, where the temperature compensation layer material is SiO2, varies with different metal duty cycles (mr) and different temperature compensation layer thicknesses (hSiO2). 2 eff Simulation diagram of the correspondence;

[0023] Figure 2D This schematically illustrates the effect of different metal duty cycles (mr) and different temperature compensation layer thicknesses (hSiO2) on the effective coupling coefficient k of an acoustic device structure according to an embodiment of the present disclosure, where the temperature compensation layer material is SiO2 and the planarization layer material is SiN. 2 eff Simulation diagram of the correspondence;

[0024] Figure 2E The corresponding diagram is shown schematically. Figure 1 The simulation diagram shows the relationship between the resonant frequency fs of the Buried TC-SAW device structure with structural defects and the temperature compensation layer material SiO2. The temperature compensation layer material is SiO2.

[0025] Figure 2F The diagram illustrates a simulation of the relationship between different metal duty cycles (mr) and different temperature compensation layer thicknesses (hSiO2) and the resonant frequency fs of an acoustic device structure according to an embodiment of the present disclosure, where the temperature compensation layer material is SiO2 and the planarization layer material is SiN.

[0026] Figure 2G The schematic illustration shows a corresponding acoustic device structure according to an embodiment of the present disclosure. Figure 2A The planar composition top view of the piezoelectric layer 201 in the cross-sectional view of the structure shown;

[0027] Figure 2H The schematic illustration shows a corresponding acoustic device structure according to another embodiment of the present disclosure. Figure 2A The planar composition top view of the piezoelectric layer 201 in the cross-sectional view of the structure shown;

[0028] Figure 3A A schematic cross-sectional view illustrating the structural composition of an acoustic device structure according to another embodiment of the present disclosure is shown.

[0029] Figure 3B The schematic illustration shows a corresponding acoustic device structure according to another embodiment of the present disclosure. Figure 3A The planar composition top view of the piezoelectric layer 301 in the cross-sectional view of the structure shown;

[0030] Figure 4A A schematic cross-sectional view illustrating the structural composition of an acoustic device structure according to another embodiment of the present disclosure is shown.

[0031] Figure 4B A schematic cross-sectional view illustrating the structural composition of an acoustic device structure according to another embodiment of the present disclosure is shown.

[0032] Figure 4C A schematic cross-sectional view illustrating the structural composition of an acoustic device structure according to another embodiment of the present disclosure is shown.

[0033] Figure 5A A schematic cross-sectional view illustrating the structural composition of an acoustic device structure according to another embodiment of the present disclosure is shown.

[0034] Figure 5B A schematic cross-sectional view illustrating the structural composition of an acoustic device structure according to another embodiment of the present disclosure is shown; and

[0035] Figure 6 The diagram schematically illustrates the equivalent circuit connection of a portion of the structural components of a filter according to an embodiment of the present disclosure. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0037] It should be noted that implementations not illustrated or described in the accompanying drawings or the main text of the specification are all forms known to those skilled in the art and are not described in detail. Furthermore, the definitions of the various elements and methods described above are not limited to the specific structures, shapes, or methods mentioned in the embodiments, and those skilled in the art can easily modify or substitute them.

[0038] It should also be noted that the directional terms mentioned in the embodiments, such as "up," "down," "front," "back," "left," and "right," are only for reference to the directions in the accompanying drawings and are not intended to limit the scope of protection of this disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted where they may cause confusion in understanding this disclosure.

[0039] Furthermore, the shapes and dimensions of the components in the figures do not reflect actual size and proportion, but are merely illustrative of embodiments of this disclosure. Additionally, any reference numerals placed between parentheses in the claims should not be construed as limiting the scope of the claims.

[0040] Furthermore, the word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0041] The use of ordinal numbers such as "first," "second," "third," etc., in the specification and claims to modify the corresponding elements does not in itself imply that the element has any ordinal number, nor does it represent the order of one element with another element or the order of manufacturing methods. The use of these ordinal numbers is only to enable a named element to be clearly distinguished from another element with the same name.

[0042] Those skilled in the art will understand that modules in the device of the embodiments can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiments can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components. Except where at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or device so disclosed. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose. Furthermore, in the unit claims enumerating several means, several of these means may be embodied by the same hardware item.

[0043] Similarly, it should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the disclosure, in the foregoing description of exemplary embodiments of the disclosure, various features of the disclosure are sometimes grouped together in a single embodiment, figure, or description thereof. However, this approach to disclosure should not be construed as reflecting an intention that the claimed disclosure requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, the aspects of the disclosure consist of fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the disclosure.

[0044] Temperature compensation layers typically possess a Young's modulus that changes positively with frequency. This means that the Young's modulus changes of these layers have an effect opposite to those of the piezoelectric and electrode layers, allowing them to compensate for frequency shifts caused by changes in the Young's modulus of each layer (which leads to changes in the sound velocity of the material structure) during temperature variations. However, SAW devices, such as the Buried TC-SAW device structure, often still face challenges even after the addition of a temperature compensation layer. Figure 1As shown, a buried TC-SAW device can form interdigitated electrodes 102 on the piezoelectric layer 101, and a temperature compensation layer 103 can be formed based on these interdigitated electrodes 102. However, this type of device structure will have another clutter mode near the main resonant mode. Specifically, when using a LiNbO3 substrate with a 128-YX chamfer, Rayleigh waves are used as the main resonant mode, and strong SH waves (Shear waves) exist near the resonant frequency. The Horizontal mode, when it falls into the filter passband, often causes huge ripples, thus affecting the performance of the filter device. Furthermore, growing a thick temperature compensation layer 103 directly on the metal surface of the interdigital electrode 102 is prone to quality issues. For example, defects such as voids and gaps may appear within the film (e.g., at the interface 104 where the upper end of the interdigital electrode 102 contacts the temperature compensation layer 103). These defects lead to a decrease in the Q value of the device, also affecting the performance of the filter device. Moreover, the grown temperature compensation layer 103 is generally quite thick, resulting in a certain thickness error during fabrication. In normal thin film fabrication processes, the ability to control this error is generally proportional to the absolute value of the film thickness. For example, growing a 2μm thick film typically results in a consistency error of ±5%, or approximately ±100nm. This error affects the device's resonant frequency and effective coupling coefficient (k...). 2 eff These factors have a significant impact.

[0045] To address this, existing technologies mention suppressing clutter modes to some extent by modifying the piezoelectric substrate. However, this clearly cannot eliminate the influence of clutter modes. Moreover, for architectures like trapezoidal filters, which are often composed of several resonators, this method is practically ineffective in simultaneously suppressing the clutter modes of all resonators. Furthermore, existing technologies also mention planarizing the temperature compensation layer to achieve specific thickness positions and thus remove voids. However, this method has extremely limited effectiveness for defects near locations such as interdigital electrodes. Moreover, variations in the thickness of the temperature compensation layer have a significant impact on device performance. Controlling the growth of a film with the highest possible thickness uniformity through manufacturing processes is quite challenging. Furthermore, the higher the resonant frequency, the more sensitive the performance changes become to the film thickness, further increasing the difficulty of the manufacturing process.

[0046] To address at least one of the aforementioned technical problems existing in existing acoustic wave device structures with temperature compensation layers, such as Buried TC-SAW devices, this disclosure provides an acoustic wave device structure, filter, and electronic device with temperature compensation characteristics.

[0047] like Figures 2A-6As shown, the first aspect of this disclosure provides an acoustic wave device structure with temperature compensation characteristics, which includes a piezoelectric layer, a temperature compensation layer, and a resonant electrode layer.

[0048] Piezoelectric layers serve as resonant structures in acoustic wave device structures;

[0049] A temperature compensation layer is disposed on at least one surface of the piezoelectric layer to provide a temperature compensation effect for the piezoelectric layer.

[0050] A resonant electrode layer is disposed on the surface of the piezoelectric layer to generate a resonant effect in conjunction with the piezoelectric layer; wherein, the resonant electrode layer includes filling sites that expose the surface of the piezoelectric layer for filling or injecting planarization material to form a planarization layer that is flush with one surface of the resonant electrode layer.

[0051] like Figure 2A As shown, the acoustic wave device structure may include a piezoelectric layer 201, a temperature compensation layer 204, and a resonant electrode layer. The piezoelectric layer 201 can serve as a substrate for the acoustic wave device structure, forming a piezoelectric substrate. The piezoelectric layer 201 is generally used to generate the resonant function of the acoustic wave device structure. Specifically, the material used to fabricate the piezoelectric layer 201 can be at least one or a mixture of at least two of aluminum nitride, zinc oxide, lithium niobate, or lithium tantalate, to further improve the resonant performance of the piezoelectric layer 201. The piezoelectric layer 201 can be a multilayer piezoelectric structure stack layer composed of one or more different piezoelectric materials.

[0052] Furthermore, a temperature compensation layer 204 can be disposed above the upper surface of the piezoelectric layer 201, with a resonant electrode layer sandwiched between them, for direct contact with the resonant electrode layer to compensate for the temperature-dependent changes in the resonant frequency of the piezoelectric layer 201. The temperature compensation layer 204 can be made of a dielectric material, specifically silicon dioxide (SiO2), phosphosilicate glass, or other materials with a positive temperature coefficient of frequency. Alternatively, the temperature compensation layer 204 can be disposed on the lower surface of the piezoelectric layer 201, i.e., not in direct contact with the resonant electrode layer.

[0053] like Figure 2B As shown, the simulation is based on the piezoelectric material 128-YX LiNbO3 for piezoelectric layer 201, and the resonant electrode layer is an interdigitated copper (Cu) interdigitated electrode layer. The temperature compensation layer is a SiO2 material with a thickness of 0.3λ (generally, there is a certain correspondence between the thickness of silicon dioxide and the period of the interdigitated electrode; λ is the period in the direction of the interdigitated electrode arrangement. For example, in a band 8 (930MHz) filter, the period λ in the direction of the interdigitated electrode arrangement is approximately 3.8µm; for details, please refer to...). Figure 2G (As shown). Therefore, when as Figure 2AWhen the temperature compensation layer 204 shown is made of the same material as the planarization layer 203, and both are SiO2, the actual structural form of this acoustic wave device can be referred to... Figure 1 The illustrated structure of the Buried TC-SAW device with structural defects is characterized by a temperature compensation layer made of SiO2, which fully covers the exposed surface of the resonant electrode layer. At this point, corresponding to... Figure 2B The solid curves shown indicate that the SiO2 temperature compensation layer 103 exhibits typical resonator impedance characteristics, with its minimum and maximum values ​​corresponding to the resonant frequency fs and anti-resonant frequency fp, respectively. With temperature changes, due to variations in the Young's modulus of materials such as the piezoelectric layer and electrode layers (which leads to changes in the material's sound velocity) and the thermal expansion characteristics of each layer, fs and fp will shift. Therefore, the temperature compensation layer generally has a Young's modulus relationship that changes positively with frequency, which is the opposite of that of electrodes such as the piezoelectric layer 101 and the interdigitated electrode 102, thus compensating for frequency changes with temperature. However, as mentioned earlier... Figure 1 The acoustic device structure of the temperature compensation layer 103 of the SiO2 material shown has significant technical defects that are difficult to overcome.

[0054] The resonant electrode layer covers the surface of the piezoelectric layer 201 and is in direct contact with the surface of the piezoelectric layer 201. To ensure the resonance effect with the piezoelectric layer 201, the material used to fabricate the resonant electrode layer can be a metal or metal alloy with good electrical conductivity. Specifically, it can be at least one of the following metals compatible with semiconductor processes: aluminum, molybdenum, copper, gold, platinum, silver, nickel, chromium, tungsten, etc., or at least two metal alloys. The resonant electrode layer can also be a multilayer electrode structure made of at least one of the above-mentioned metal materials.

[0055] Relative to the contact between the resonant electrode layer and the piezoelectric layer 201, the filling site on the resonant electrode layer can be an open structure, specifically a gap, opening, or other opening on the resonant electrode layer, used to expose the surface of the piezoelectric layer 201 relative to the resonant electrode layer, preventing the resonant electrode layer from completely covering the piezoelectric layer 201. Therefore, planarization material can be filled or injected into these filling sites to form a planarization layer 203 relative to the resonant electrode layer and the piezoelectric layer 201. This planarization layer 203 is flush with the upper surface of the resonant electrode layer, meaning that the other surface of both layers that will not contact the piezoelectric layer 201 is at the same height, thus achieving a planarization effect.

[0056] The planarization material of the planarization layer 203 is a dielectric material, and its thickness can be the same as or similar to that of the resonant electrode layer. However, the planarization layer 203 and the resonant electrode layer must be flush with the back surface of the piezoelectric layer 201 to form a planarization interface. Compared with the traditional TC-SAW structure, the planarization material of the planarization layer 203 in this embodiment is a high-velocity dielectric material different from that of the temperature compensation layer 204, specifically silicon nitride (SiN), aluminum nitride, etc.

[0057] like Figure 2B As shown, the simulation is based on the piezoelectric material 128-YX LiNbO3 for piezoelectric layer 201, the resonant electrode layer is an interdigitated copper (Cu) electrode layer, and the temperature compensation layer is a SiO2 material with a thickness of 0.3λ. Therefore, when... Figure 2A When the temperature compensation layer 204 shown is made of SiO2 and the planarization material is SiN, the actual structural form of this acoustic wave device can be referred to Figure 2A The acoustic device structure shown in this embodiment of the present disclosure is configured such that the temperature compensation layer 204 only covers the upper surface of the resonant layer, while its side surfaces are covered by the planarization layer 203. At this time, corresponding to... Figure 2B The dashed curve shows the minimum equivalent impedance at the temperature-compensated resonant frequency. Because the SiN planarization material of the planarization layer 203 (the SiN planarization layer 203 can increase the overall sound velocity of the device, resulting in a higher resonant frequency) has a higher sound velocity than the SiO2 material, the dashed curve represents the higher resonant frequency of the SiN planarization layer 203 structure, exceeding the anti-resonant frequency fp. Both structures exhibit clutter mode SH waves. However, since the resonant frequencies fs and fp, as well as the clutter mode frequencies, at each resonant point on the device impedance curve are related to the device structure and the materials used, the degree of shift of the SiN planarization layer 203 structure towards fs, fp, and clutter mode frequencies is significantly different from the full coverage effect of the SiO2 temperature-compensated layer. Therefore, different clutter modes are farther from the resonant frequencies fs and fp. It is evident that for trapezoidal filter structures where resonant and anti-resonant effects constitute the filter passband, the aforementioned planarization layer 203 based on SiN material can shift the clutter mode to a higher frequency, helping to reduce its impact on the filter passband and roll-off. Therefore, adding the SiN-based planarization layer 203 can reduce the passband or roll-off ripple caused by clutter modes.

[0058] Furthermore, such as Figure 2C and Figure 2D As shown, for all temperature compensation layer materials being SiO2, the effective coupling coefficient k of SiO2 to the device varies with different metal duty cycles mr and different temperature compensation layer thicknesses h.2 eff Impact, such as Figure 2C and Figure 2D As shown, the coefficient k decreases towards the left and increases towards the right. This indicates that as the thickness h of the temperature compensation layer (SiO2) increases from 0.15λ to 0.5λ, the effective coupling coefficient k... 2 eff It shows a downward trend. As the metal duty cycle mr changes from 0.3 to 0.75, the effective coupling coefficient k... 2 eff There is a tendency for these two parameters to first increase and then decrease. Therefore, when designing a filter based on this acoustic device structure, the values ​​of both parameters may vary within the range shown in the figure, but overall, as... Figure 2D As shown, in this embodiment of the present disclosure, when a planarization layer 203 is used and it is made of SiN material, the effective coupling coefficient k of the acoustic wave device structure is... 2 eff Furthermore, the structural design of the planarization layer 203 clearly facilitates the design of filters with greater bandwidth.

[0059] like Figure 2E and Figure 2F The figure shows a simulation of the relationship between the resonator frequency fs of the device and the thickness h of the temperature compensation layer SiO2 for different metal duty cycles mr. Figure 2E The acoustic device structure shown corresponds to Figure 1 In the conventional device structure shown, the material of the planarization layer and the temperature compensation layer are the same, both being SiO2. Figure 2F The acoustic device structure shown corresponds to Figure 2A In the device structure of the embodiment shown in this disclosure, the planarization layer is made of SiN, and the temperature compensation layer 204 can be made of SiO2. It can be seen that, with a fixed duty cycle parameter, the resonant frequency fs generally increases and then decreases with the thickness h of the temperature compensation layer (SiO2). However, if a thinner temperature compensation layer (h SiO2) is used, the temperature compensation effect is poor, and the device structure becomes more sensitive to temperature changes. Therefore, for filters with strict requirements for insertion loss, roll-off, and suppression, a thicker temperature compensation layer is generally required to reduce the influence of the temperature of the piezoelectric layer 201 on the frequency.

[0060] It should be noted that, as mentioned above, it is actually difficult to ensure the consistency of the thickness of the entire wafer during the manufacturing process of a thicker temperature compensation layer. This often leads to differences (errors) in the layer thickness of different regions, resulting in changes in device characteristics such as frequency and effective coupling coefficient. Moreover, it places strict requirements on the fabrication process of the temperature compensation layer in order to control the growth of a film layer with good uniformity as much as possible, which directly makes the fabrication process of temperature compensation more difficult. In addition, when the resonant frequency fs is higher, the sensitivity of device performance changes to film thickness becomes more obvious, further increasing the difficulty of process operation.

[0061] However, as Figure 2F As shown, when SiN is used as the material for the planarization layer 203 in this embodiment of the present disclosure, relative to the horizontal axis of the temperature compensation layer thickness hSiO2(λ), which is generally in the range of 0.3-0.4, among the five curves corresponding to different mr, the curve segment on the left side of the curve group located in this range is significantly smoother than the curve on the right side. That is, the resonant frequency fs changes more smoothly with the thickness hSO2 of the temperature compensation layer 204 (specifically, refer to the slope of the corresponding curve). In other words, the planarization layer 203 of the SiN material can effectively reduce the sensitivity to frequency changes.

[0062] As mentioned above, such as Figure 1 The diagram illustrates a traditional structure where the temperature compensation layer is grown directly on the metal layer. However, the quality of this relatively thick temperature compensation layer, grown directly on the metal surface, is prone to problems. For example, voids and gaps can easily appear within the film, especially in the area immediately adjacent to the electrode metal (104). These defects directly lead to a decrease in the device's Q value, thus affecting the filter device's performance.

[0063] However, to maintain the flatness of the planarization layer 203 and the resonant electrode layer on one side, after completing the fabrication process of the planarization layer 203 and the resonant electrode layer, it is necessary to simultaneously planarize the corresponding one-sided surfaces of the resonant electrode layer and the planarization layer 203. This allows defects such as voids and gaps that appear in the adjacent positions to be removed through the planarization process. Therefore, the structural design of the planarization layer 203 and the resonant electrode layer with the flatness of one side surface in the embodiments of this disclosure can avoid the influence of traditional defects such as voids and gaps. In addition, when the temperature compensation layer 204 is in contact with the one-sided surface of the planarization layer 203 and the resonant electrode layer, the flatness of the one-sided surface of the temperature compensation layer 204 is also required to improve the Q value of the device and enhance the filtering performance of the device through good flat surface contact. In other words, the structural design of the planarization layer 203 and the resonant electrode layer can significantly improve the Q value of the device and ensure device performance. Specifically, the material used to prepare the planarization layer 203 is generally a material with a Young's modulus that changes negatively with temperature, such as SiN, so it generally has no temperature compensation effect. Since the area of ​​device vibration is on the surface of the piezoelectric layer, the temperature compensation layer should ideally be in direct contact with the surface of the piezoelectric layer or the resonant electrode layer that is in direct contact with the surface of the piezoelectric layer in order to achieve a better temperature compensation effect.

[0064] Therefore, by using the planarization layer 203 that is flush with the surface of the resonant electrode layer, the acoustic device structure can effectively reduce problems such as gaps and slots at the interface of the temperature compensation layer caused by process defects. At the same time, the planarization layer 203 can move parasitic clutter modes near the resonant frequency away from the main resonant peak, improve the overall effective coupling coefficient of the device, and reduce the sensitivity of the temperature compensation layer to the frequency.

[0065] like Figure 2A , Figure 2G and Figure 2H As shown, according to an embodiment of the present disclosure, the resonant electrode layer includes a first interdigital electrode 221 and a second interdigital electrode 222.

[0066] The first interdigital electrode 221 has a first busbar and a plurality of first interdigitals connected to the first busbar;

[0067] The second interdigital electrode 222 has a second busbar and a plurality of second interdigitals connected to the second busbar.

[0068] In this process, multiple second interdigitates and multiple first interdigitates are intersected and parallel to each other on the surface of the piezoelectric layer to form an interdigitated effect.

[0069] like Figure 2G and Figure 2HAs shown, the first interdigital electrode 221 and the second interdigital electrode 222 form an interdigitated effect. The first interdigital electrode 221 can serve as the input electrode for the resonant effect, while the second interdigital electrode 222 can serve as the corresponding output electrode. This causes the resonant electrode layer to exhibit a surface acoustic wave (SAW) resonance on the surface of the piezoelectric layer 201, specifically referring to the resonance mode of a SAW device. The first interdigital electrode 221 and the second interdigital electrode 222, through their respective busbars and the interdigitated distribution of multiple interdigits on the surface of the piezoelectric layer 201, can form gaps between them. These gaps can all serve as the aforementioned filler sites.

[0070] Therefore, the acoustic device structure described in the present disclosure can be applied to surface acoustic wave-based devices to provide higher and more stable device performance.

[0071] like Figure 2A , Figure 2G and Figure 2H As shown, according to an embodiment of this disclosure, the gap formed by the first interdigital electrode and the second interdigital electrode in the parallel and interlaced structural relationship is a fill position; or the gap between the first interdigital electrode and the second interdigital electrode corresponding to the effective resonant region between the resonant electrode layer and the piezoelectric layer is a fill position.

[0072] like Figure 2G As shown, on the surface region of the piezoelectric layer 201 between the first busbar of the first interdigital electrode 221 and the second busbar of the second interdigital electrode 222, all the gaps on the exposed surface of the piezoelectric layer 201 formed by the interlacing of multiple first interdigitates and multiple second interdigitates can be used as filling sites to achieve the filling of planarization material and form a planarization layer 203 located between these gaps and in contact with the side surfaces of adjacent interdigitates. At this time, the gaps corresponding to the overlapping and non-overlapping areas of the interdigitate electrodes between the first busbar and the second busbar are all considered as the area where the planarization layer 203 is located.

[0073] like Figure 2H As shown, relative to Figure 2GIn the acoustic device structure shown, the planarization layer 203′ can cover only the overlapping area of ​​the interdigitated fingers of the first interdigital electrode 221 and the second interdigital electrode 222, that is, the gap between the interdigitated fingers of the two electrodes and the effective region of resonance effect between the piezoelectric layer 201, as the filling site. Since the resonance effect of the piezoelectric layer 201 mainly plays a role in this effective region, it is only necessary to ensure the film quality and flatness of the temperature compensation layer 204 in this region. The planarization layer 203′, which is made of high sound velocity material (such as SiN) filling the filling site, has a good smoothness on the surface in contact with the temperature compensation layer 204, which helps to increase the overall sound velocity in the effective resonance region and form a sound velocity difference with the end of the interdigitated electrode. While effectively confining the sound wave within the effective region, it suppresses the transverse parasitic mode, thereby improving the Q value of the device.

[0074] It should be noted that the overlapping area of ​​the interdigitated fingers of the first interdigital electrode 221 and the second interdigital electrode 222 mentioned above does not actually include the end regions of the first interdigital electrode 221 and the second interdigital electrode 222 along the interdigital electrode direction. For details, please refer to... Figure 2H As shown.

[0075] like Figure 3A and Figure 3B As shown, according to an embodiment of the present disclosure, the resonant electrode layer 302 is a planar thin film electrode layer disposed on the surface of the piezoelectric layer 301, and the filling position includes at least one filling hole, which penetrates the planar thin film electrode layer and exposes the surface of the piezoelectric layer 301.

[0076] When the resonant electrode layer 302 disposed on one surface of the piezoelectric layer 301 is a planar thin-film electrode layer, it can cooperate with another lower electrode layer disposed on the other surface of the piezoelectric layer 301, so that the resonant electrode layer 302 and the piezoelectric layer 301 exhibit a bulk acoustic wave resonance, which can be referred to in the resonance mode of BAW devices. The filling site has multiple filling holes, which can be distributed in an array on the resonant electrode layer 302. Each filling hole is a through hole that penetrates the resonant electrode layer 302, so that the surface of the piezoelectric layer 301 can be exposed for filling with a corresponding planarization material, such as SiN, to form a planarization layer 303 based on these filling holes.

[0077] In this way, the above can be achieved. Figure 2A Based on the beneficial effects shown, the acoustic device structure described in the present disclosure can be applied to devices based on bulk surface waves, providing higher and more stable device performance.

[0078] like Figures 4A-4C As shown, according to embodiments of this disclosure, the acoustic device structure further includes a first protective layer and / or a second protective layer.

[0079] The first protective layer corresponds to one surface of the piezoelectric layer and is disposed on one surface of the corresponding temperature compensation layer.

[0080] The second protective layer corresponds to the other surface of the piezoelectric layer and is disposed on the flat surface formed by the resonant electrode layer and the planarization layer.

[0081] The acoustic device structure of this embodiment may specifically include a piezoelectric layer 401, a resonant electrode layer 402, a planarization layer 403, and a temperature compensation layer 404. The resonant electrode layer 402 may be as follows: Figure 2A , Figure 2G and Figure 2H The diagram shows an interdigitated electrode layer. The resonant electrode layer 402 and the planarization layer 403 each have a flattened surface on one side. Furthermore, to provide waterproofing, isolation, and sealing protection, the acoustic wave device structure may also have a corresponding protective layer. This protective layer typically covers the surface of the temperature compensation layer 4, the single-sided surface of the resonant electrode layer 402 and the planarization layer 403 with their planarization effect, or both surfaces, thereby providing protection and isolation to the temperature compensation layer to prevent moisture ingress.

[0082] Specifically, such as Figure 4A As shown, the acoustic wave device structure forms a resonant electrode layer 402 and a planarization layer 403 with a single-sided planarized surface on the surface of the piezoelectric layer 401, and a temperature compensation layer 404 is formed on the single-sided planarized surface of the resonant electrode layer 402 and the planarization layer 403. Furthermore, a protective layer 405 is formed on the surface of the temperature compensation layer 404. Figure 4B As shown, the acoustic wave device structure forms a resonant electrode layer 402 and a planarization layer 403 with a single-sided planarized surface on the surface of the piezoelectric layer 401. A protective layer 451 is directly formed on the single-sided planarized surface of the resonant electrode layer 402 and the planarization layer 403. Furthermore, a temperature compensation layer 441 is formed on the other surface of the piezoelectric layer 401, and a protective layer 452 is further formed on the lower surface of the temperature compensation layer 441. Figure 4C As shown, the acoustic wave device structure forms a resonant electrode layer 402 and a planarization layer 403 with a single-sided planarized surface on the surface of the piezoelectric layer 401. A temperature compensation layer 442 is formed on the single-sided planarized surface of the resonant electrode layer 402 and the planarization layer 403. A protective layer 453 is further formed on the upper surface of the temperature compensation layer 442. A temperature compensation layer 443 is formed on the other surface of the piezoelectric layer 401. A protective layer 454 is further formed on the lower surface of the temperature compensation layer 443. The protective layer can also be designed according to other embodiments, and there are no specific limitations.

[0083] By utilizing the design of the aforementioned protective layer, the lifespan of the device can be significantly improved, ensuring the technical effects of "effectively reducing gaps and slots at the interface of the temperature compensation layer caused by process defects, while the planarization layer 203 can move parasitic clutter modes near the resonant frequency away from the main resonant peak, thereby improving the overall effective coupling coefficient of the device and reducing the sensitivity of the temperature compensation layer to the frequency," thus enhancing the structural stability of the device.

[0084] It should be noted that the acoustic wave device structure may also include an edge reflection layer located above the resonant electrode layer for suppressing lateral modes, a metal connection layer connecting the interdigital electrodes and leading them to the external structure, etc. The specific design can be adjusted according to the actual needs of the device structure, and will not be elaborated here. When the piezoelectric layer is thin, the acoustic wave device structure may also have a substrate structure to enhance structural stability and improve device performance. The substrate structure can be made of one or more of silicon, quartz, and alumina, or a stacked structure of multiple materials. Furthermore, the materials used to prepare the various electrode layers mentioned in the embodiments of this disclosure can be consistent with the materials used to prepare the resonant electrode layer, and will not be elaborated here either.

[0085] like Figure 5A and Figure 5B As shown, according to an embodiment of the present disclosure, the piezoelectric layer 501 includes an electrode groove, which is recessed on the surface of the piezoelectric layer 501 for providing a resonant electrode layer 502.

[0086] The acoustic device structure of this embodiment may specifically include a piezoelectric layer 501, a resonant electrode layer 502, and a temperature compensation layer 504. The resonant electrode layer 502 may be as follows: Figure 2A , Figure 2G and Figure 2H The diagram shows an interdigitated electrode layer. Because the electrode grooves are recessed on the surface of the piezoelectric layer 501, the resonant electrode layer 502, when formed within these grooves, is embedded in the piezoelectric layer 501, forming an embedded electrode and achieving a more stable structural connection with the piezoelectric layer 501. Furthermore, the electrode grooves recessed on the surface of the piezoelectric layer 501 allow for dimensional compression of the acoustic device structure in the vertical direction.

[0087] Furthermore, when the aforementioned embedded electrode structure is partially embedded in the piezoelectric layer 501, it can achieve piezoelectric contact in multiple directions, compared to the case of unidirectional contact on the surface of the piezoelectric layer. Since the inverse piezoelectric effect is achieved by using the signal in the electrode to excite the piezoelectric layer to vibrate at the input electrode, the sound wave is transmitted to the output electrode, and the output signal is generated at the output electrode again by relying on the piezoelectric effect, realizing the energy conversion of electro-acoustic-electric. Therefore, the larger contact area between the resonant electrode layer 502 and the piezoelectric layer 501 can further stimulate the piezoelectric characteristics, improve the effective coupling coefficient, and thus further improve the device performance.

[0088] like Figure 5A As shown, according to an embodiment of the present disclosure, the depth of the electrode groove is less than the thickness of the resonant electrode layer 502.

[0089] The acoustic device structure of this disclosure may further include a planarization layer 503. For example... Figure 5A As shown, when the depth of the electrode groove is less than the thickness of the resonant electrode layer 502, it indicates that the resonant electrode layer 502 is partially embedded in the surface of the piezoelectric layer 501, while another part protrudes beyond the surface of the piezoelectric layer 501. Thus, the surface of the piezoelectric layer 501 can be divided by the portion of the resonant electrode layer 502 protruding beyond its surface, forming a gap relative to the resonant electrode layer 502 as a filling site for the planarization layer 503. This filling site is then filled with planarization material, and after the planarization material is filled, the combination of the planarization layer and the resonant electrode layer is planarized, ultimately forming the planarization layer 503 and the resonant electrode layer 502.

[0090] This allows for a larger contact area between the piezoelectric layer 501 and the resonant electrode layer 502, better improving the effective coupling coefficient of the device and consequently enhancing its overall performance. Furthermore, as... Figure 5A As shown, by means of the electrode groove recessed on the surface of the piezoelectric layer 501, the size of the acoustic device structure can be compressed in the vertical direction.

[0091] like Figure 5B As shown, according to an embodiment of this disclosure, the depth of the electrode groove is equal to the thickness of the resonant electrode layer 502, and the surface of the piezoelectric layer 501 without electrode grooves forms a filling position.

[0092] The acoustic device structure of this disclosure may further include a planarization layer 503'. For example... Figure 5BAs shown, when the depth of the electrode trench is equal to the thickness of the resonant electrode layer 502, it indicates that the resonant electrode layer 502 is completely embedded in the surface of the piezoelectric layer 501. Thus, a pattern of the piezoelectric layer 501 relative to the resonant electrode layer 502 can be formed. The exposed piezoelectric surface region of the piezoelectric layer 501 of the resonant electrode layer 502, which is positioned opposite to the resonant electrode layer 502 in this pattern, can be used to form the filling sites of the planarization layer 503'. A planarization material implantation or implantation process is performed on these filling sites, allowing the corresponding planarization material to enter the exposed surface of the piezoelectric layer 501 in a high-concentration doped form, forming a doped layer of a predetermined thickness, which serves as the planarization layer 503'.

[0093] At this point, since the depth of the electrode trench is the same as that of the resonant electrode layer 502, the entire resonant electrode layer 502 is integrated into the piezoelectric layer 501. Therefore, planarization can be performed directly after the resonant electrode layer 502 is grown, followed by the implantation or embedding of planarization material onto the exposed surface of the piezoelectric layer 501. Planarization of the planarization layer 503′ is no longer necessary, and planarization of one side of both the planarization layer 503′ and the resonant electrode layer 502 can be achieved. This further increases the contact area between the piezoelectric layer 501 and the resonant electrode layer 502, improving the effective coupling coefficient of the device and consequently enhancing the overall device performance. It also further reduces the size of the device structure in the vertical direction. As long as the contact effect between the temperature compensation layer and the resonant electrode layer or the piezoelectric layer is maintained, the corresponding temperature compensation effect can be achieved.

[0094] Therefore, as Figure 5A and Figure 5B As shown, by means of the electrode groove recessed on the surface of the piezoelectric layer 501, the size of the acoustic device structure can be compressed in the vertical direction, which is beneficial to the miniaturization, integration and precision of the acoustic device structure. Compared with the structural design of laying the resonant electrode flat on the surface of the piezoelectric layer, it can significantly improve the structural stability between the piezoelectric layer 501 and the resonant electrode layer 502, and obtain better device performance by increasing the piezoelectric contact area.

[0095] In summary, the acoustic device structure with temperature compensation characteristics described in the embodiments of this disclosure can shift parasitic modes near the resonant frequency to a more distant frequency, significantly improve the effective coupling coefficient of the device, effectively reduce the sensitivity of the temperature compensation layer to the frequency, reduce gaps and voids in the temperature compensation layer caused by process defects, enhance structural stability, compress the vertical dimensions of the device structure, and reduce the manufacturing cost of the device structure, which will not be elaborated here.

[0096] The second aspect of this disclosure provides a method for fabricating the aforementioned acoustic wave device structure with temperature compensation characteristics. For example... Figure 2A As shown, in the fabrication process of the above-mentioned acoustic device structure disclosed herein, the resonant electrode layer structure is generally first grown and patterned, then a planarization layer is grown on the surface of the piezoelectric layer and the resonant electrode layer, and planarization treatment such as chemical mechanical polishing (CMP) is performed to smooth the surface of one side of the two until the resonant electrode layer reaches the preset thickness, and finally a temperature compensation layer is grown on the final device structure.

[0097] Furthermore, the growth order of the resonant electrode layer (such as the interdigitated electrode) and the planarization layer can be interchanged, as long as the final two layers have smooth surfaces that are flat on one side to avoid affecting the film quality of the subsequent temperature compensation layer growth. The planarization of the surfaces on one side can be achieved through chemical mechanical polishing (CMP), which generally ensures that the two layers are at least flat on one side. Therefore, forming smooth surfaces on one side of the resonant electrode layer and the planarization layer also helps in the subsequent growth of a high-quality temperature compensation layer, controlling the surface flatness of the temperature compensation layer, reducing device defects, and thus significantly improving the Q value. Moreover, the planarization of the planarization layer ensures that it does not obstruct the contact between the end faces of the temperature compensation layer and the electrode layer. With the help of the corresponding planarized surface, the surface flatness of the temperature compensation layer can be more easily controlled during the fabrication process, thereby significantly reducing fabrication costs.

[0098] The specific process steps of the method for preparing the acoustic device structure in the above-described embodiments of the present disclosure may be adjusted according to the different actual acoustic device structures, and will not be elaborated further.

[0099] like Figure 6 As shown, a third aspect of this disclosure provides a filter, which includes a main path, at least one parallel path, and at least one resonator.

[0100] One end of the main path is connected to the input port Tx, and the other end is connected to the output port Ant;

[0101] At least one parallel path is connected to the main path and maintains a parallel relationship with the main path;

[0102] At least one resonator is connected to one of the parallel paths in at least one parallel path, wherein at least one of the at least one resonator includes the acoustic device structure with temperature compensation characteristics described above.

[0103] like Figure 6As shown, the filter is a trapezoidal filter composed of multiple acoustic resonator units. Specifically, it is constructed from several series branch resonator modules 601 and parallel branch resonator modules 602. Specifically, the series branch resonator module 601 has multiple acoustic resonators 611, 612 and 613 connected in series on the main path, while the parallel branch resonator module 602 has multiple acoustic resonators 621, 622 and 623 connected on their respective parallel paths, thus forming the corresponding trapezoidal filter structure.

[0104] In this filter, since the anti-resonance frequency fp of its parallel resonators generally falls within the passband, and the resonant frequency fs of its series resonators also generally falls within the passband, the anti-resonance frequencies of each parallel resonator in the parallel branch resonator module 602 and the resonant frequencies of each series resonator in the series branch resonator module 601 will appear within the passband of the filter. Therefore, as a preferred embodiment of this filter, at least one or more parallel resonators in the parallel branch resonator module 602 can be subjected to the above-described configuration. Figures 2A-6 The described acoustic device structure with temperature compensation characteristics enables the high-frequency clutter modes of the filter to be shifted to higher frequencies, thereby avoiding the influence of clutter modes on the filter passband. It should be noted that one or more of the series resonators in the series branch resonator module 601 can also be described using the acoustic device structure with temperature compensation characteristics described in the above embodiments of this disclosure.

[0105] Therefore, for filter structures where resonant and anti-resonant effects typically define the filter passband, the aforementioned planarization layer structure based on SiN material can be used to shift the clutter mode to a higher frequency, helping to reduce its impact on the filter passband and roll-off. Thus, adding a SiN-based planarization layer can effectively reduce the passband or roll-off ripple caused by clutter modes.

[0106] A fourth aspect of this disclosure provides an electronic device that includes the aforementioned filter. This electronic device can be a mobile phone, laptop, tablet computer, POS machine, in-vehicle computer, or other mobile or fixed computer device, or other communication electronic devices with intelligent information processing capabilities that can utilize high-frequency, high-bandwidth technologies such as 4G or 5G.

[0107] The embodiments of this disclosure have now been described in detail with reference to the accompanying drawings.

[0108] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A structure for an acoustic wave device with temperature compensation characteristics, wherein, include: The piezoelectric layer serves as the resonant structure of the acoustic wave device. A temperature compensation layer is provided on at least one surface of the piezoelectric layer to provide a temperature compensation effect for the piezoelectric layer. A resonant electrode layer is disposed on the surface of the piezoelectric layer for cooperating with the piezoelectric layer to generate a resonant effect; wherein, the resonant electrode layer comprises: The filling site exposes the surface of the piezoelectric layer and is used to fill or inject planarization material to form a planarization layer that is flush with one surface of the resonant electrode layer. The sound velocity of the planarization material is higher than that of the temperature compensation layer, the Young's modulus of the planarization material changes negatively with temperature, and the Young's modulus of the temperature compensation layer changes positively with temperature.

2. The acoustic device structure according to claim 1, wherein, The resonant electrode layer includes: The first interdigital electrode has a first busbar and a plurality of first interdigitals connected to the first busbar; The second interdigitated electrode has a second busbar and a plurality of second interdigitated fingers connected to the second busbar, wherein the plurality of second interdigitated fingers and the plurality of first interdigitated fingers are parallel to each other and interlaced on the surface of the piezoelectric layer to form an interdigitated effect.

3. The acoustic device structure according to claim 2, wherein, The gap formed by the first interdigital electrode and the second interdigital electrode in the parallel interlaced structural relationship is the filling position; or The gap between the first interdigital electrode and the second interdigital electrode corresponding to the effective resonant region between the resonant electrode layer and the piezoelectric layer is the fill position.

4. The acoustic device structure according to claim 1, wherein, The resonant electrode layer is a planar thin-film electrode layer disposed on the surface of the piezoelectric layer, and the filling sites include: At least one filling hole is provided, through which the planar thin-film electrode layer is penetrated, exposing the surface of the piezoelectric layer.

5. The acoustic device structure according to claim 3 or 4, wherein, Also includes: A first protective layer, corresponding to one surface of the piezoelectric layer, is disposed on one surface of the corresponding temperature compensation layer; and / or The second protective layer, corresponding to the other surface of the piezoelectric layer, is disposed on the flat surface formed by the resonant electrode layer and the planarization layer.

6. The acoustic device structure according to claim 3 or 4, wherein, The piezoelectric layer includes: An electrode groove, recessed on the surface of the piezoelectric layer, is used to set the resonant electrode layer.

7. The acoustic device structure according to claim 6, wherein, The depth of the electrode groove is less than the thickness of the resonant electrode layer.

8. The acoustic device structure according to claim 6, wherein, The depth of the electrode groove is equal to the thickness of the resonant electrode layer, and the surface of the piezoelectric layer without the electrode groove forms the filling position.

9. A filter, wherein, include: The main path connects to the input port at one end and the output port at the other. At least one parallel path is connected to the main path and maintains a parallel relationship with the main path; At least one resonator is connected to one of the at least one parallel paths, wherein at least one of the at least one resonator comprises an acoustic device structure with temperature compensation characteristics as described in any one of claims 1-8.

10. An electronic device, wherein, Includes the filter as described in claim 9.

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