Surface acoustic wave devices, filters and RF front-end modules

Abstract

The present application provides a surface acoustic wave device, a filter and a radio frequency front-end module, wherein the surface acoustic wave device comprises a piezoelectric substrate, an interdigital transducer and an auxiliary structure, wherein the interdigital transducer is arranged on the piezoelectric substrate; in the arrangement direction of the two bus bars of the interdigital transducer, there is a crossover region between the two bus bars, and the crossover region comprises an intermediate region and edge regions located at both ends of the intermediate region; wherein, in the arrangement direction of the electrode fingers of the interdigital transducer, the crossover region is a region where the electrode fingers overlap each other; the electrode fingers comprise a widening portion located in the edge region; the auxiliary structure is located in the edge region; wherein, in the same edge region, the projections of the widening portion and the auxiliary structure in the top view direction are at least partially staggered along the length extension direction of the electrode fingers, and the acoustic impedance of the region provided with the widening portion is different from the acoustic impedance of the region provided with the auxiliary structure. The surface acoustic wave device, the filter and the radio frequency front-end module can better suppress high-order transverse modes and low-order transverse modes.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a surface acoustic wave device, a filter and a radio frequency front-end module. Background Art

[0002] Surface acoustic wave devices utilize the characteristics of acoustic-electric transducers to process acoustic signals propagating on the surface of a piezoelectric substrate. Surface acoustic wave devices have the advantages of low cost, small size, and multiple functions, and therefore have been widely used in radar, communication, navigation, identification, and other fields. Surface acoustic wave devices include interdigital transducers (IDTs), which can convert electrical signals into acoustic signals or convert acoustic signals into electrical signals. The transverse mode of the surface acoustic wave device can cause acoustic wave leakage, thereby causing acoustic energy loss and reducing the quality factor value. However, the surface acoustic wave devices in the related art have unreasonable structural design, and the suppression effect of the transverse mode of the surface acoustic wave device is not ideal. Utility Model Content

[0003] The present application provides a surface acoustic wave device, a filter and a radio frequency front-end module, aiming to achieve better suppression of high-order lateral modes and low-order lateral modes.

[0004] The present application provides a surface acoustic wave device, the surface acoustic wave device comprising:

[0005] Piezoelectric substrate;

[0006] An interdigital transducer is provided on the piezoelectric substrate; in the arrangement direction of the two bus bars of the interdigital transducer, there is a crossover area between the two bus bars, and the crossover area includes a middle area and edge areas located at both ends of the middle area; wherein, in the arrangement direction of the electrode fingers of the interdigital transducer, the crossover area is an area where the electrode fingers overlap each other; and the electrode finger includes a widened portion located at the edge area;

[0007] an accessory structure located in said marginal zone;

[0008] Among them, in the same edge area, the projections of the widened portion and the auxiliary structure in the top view are at least partially staggered along the length extension direction of the electrode finger, and the acoustic impedance of the area where the widened portion is provided is different from the acoustic impedance of the area where the auxiliary structure is provided.

[0009] The present application also provides a surface acoustic wave device, the surface acoustic wave device comprising:

[0010] Piezoelectric substrate;

[0011] An interdigital transducer is provided on the piezoelectric substrate; in the arrangement direction of the two bus bars of the interdigital transducer, there is a crossover area between the two bus bars, and the crossover area includes a middle area and edge areas located at both ends of the middle area; wherein, in the arrangement direction of the electrode fingers of the interdigital transducer, the crossover area is an area where the electrode fingers overlap each other; and the electrode finger includes a widened portion located at the edge area;

[0012] an auxiliary structure, at least one of the two edge regions being provided with the widened portion and the auxiliary structure;

[0013] Wherein, within the same edge region, the projections of the widened portion and the auxiliary structure in the plan view are at least partially staggered along the length extension direction of the electrode finger;

[0014] The subsidiary structure is a conductive structure, and includes a plurality of subsidiary blocks. In the arrangement direction of the electrode fingers, the subsidiary blocks are sequentially arranged at intervals; in the top view direction, each electrode finger is arranged in contact with one subsidiary block;

[0015] A dielectric layer is disposed on the piezoelectric substrate and covers the interdigital transducer and the auxiliary structure.

[0016] The present application also provides a surface acoustic wave device, the surface acoustic wave device comprising:

[0017] Piezoelectric substrate;

[0018] An interdigital transducer is provided on the piezoelectric substrate; in the arrangement direction of the two bus bars of the interdigital transducer, there is a crossover area between the two bus bars, and the crossover area includes a middle area and edge areas located at both ends of the middle area; wherein, in the arrangement direction of the electrode fingers of the interdigital transducer, the crossover area is an area where the electrode fingers overlap each other; and the electrode finger includes a widened portion located at the edge area;

[0019] an auxiliary structure, at least one of the two edge regions being provided with the widened portion and the auxiliary structure;

[0020] Among them, in the same edge area, the projections of the widened portion and the auxiliary structure in the top-view direction are at least partially staggered along the length extension direction of the electrode finger; the auxiliary structure is a non-conductive structure; and in the top-view direction, a dielectric layer is provided between the auxiliary structure and the interdigital transducer.

[0021] The present application also provides a surface acoustic wave device, the surface acoustic wave device comprising:

[0022] Piezoelectric substrate;

[0023] An interdigital transducer is provided on the piezoelectric substrate; in the arrangement direction of the two bus bars of the interdigital transducer, there is a crossover area between the two bus bars, and the crossover area includes a middle area and edge areas located at both ends of the middle area; wherein, in the arrangement direction of the electrode fingers of the interdigital transducer, the crossover area is an area where the electrode fingers overlap each other; and the electrode finger includes a widened portion located at the edge area;

[0024] An auxiliary structure is located in the edge region, the auxiliary structure includes a first region, a second region and a third region, and in the length extension direction of the electrode finger, the first region and the third region are respectively located on two sides away from the second region;

[0025] Wherein, within the same edge region, the auxiliary structure covers the widened portion, and a projection of the second region in a plan view overlaps with the widened portion along a length extension direction of the electrode finger.

[0026] The present application also provides a surface acoustic wave device, the surface acoustic wave device comprising:

[0027] Piezoelectric substrate;

[0028] An interdigital transducer is provided on the piezoelectric substrate; in the arrangement direction of the two bus bars of the interdigital transducer, there is a crossover area between the two bus bars, and the crossover area includes a middle area and edge areas located at both ends of the middle area; wherein, in the arrangement direction of the electrode fingers of the interdigital transducer, the crossover area is an area where the electrode fingers overlap each other; and the electrode finger includes a widened portion located at the edge area;

[0029] an accessory structure located in said marginal zone;

[0030] The widened portion includes a fourth region, a fifth region and a sixth region, and in the length extension direction of the electrode finger, the fourth region and the sixth region are respectively located on two opposite sides of the fifth region;

[0031] In the same edge region, a projection of the auxiliary structure in a plan view overlaps with the fifth region along a length extension direction of the electrode finger.

[0032] An embodiment of the present application also provides a filter, comprising the surface acoustic wave device as described in any one of the above items.

[0033] An embodiment of the present application also provides a radio frequency front-end module, comprising a surface acoustic wave device as described in any of the above items.

[0034] The surface acoustic wave device, filter and RF front-end module provided by the embodiments of the present application are characterized in that, at the same edge area of ​​the interdigital transducer of the surface acoustic wave device, the projections of the widened portion and the auxiliary structure in the top-view direction are at least partially staggered along the length extension direction of the electrode finger; in the same edge area, the acoustic impedance of the area provided with the widened portion is different from the acoustic impedance of the area provided with the auxiliary structure. By staggering the projections of the widened portion and the auxiliary structure in the top-view direction in the same edge area along the length extension direction of the electrode finger at least partially, the acoustic impedance of the edge area is adjusted so that the acoustic impedance of the area provided with the widened portion is different from the acoustic impedance of the area provided with the auxiliary structure, so that the surface acoustic wave device can better suppress both high-order transverse modes and low-order transverse modes, thereby effectively suppressing the transverse modes of the surface acoustic wave device, minimizing the adverse effects of the transverse modes on the surface acoustic wave device as much as possible, and effectively preventing energy leakage.

[0035] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory and cannot limit the disclosure of the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 is a schematic structural diagram of a surface acoustic wave device provided in one embodiment of the present application;

[0038] Figure 2 is a schematic structural diagram of a surface acoustic wave device provided in one embodiment of the present application;

[0039] Figure 3 It is a partial structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0040] Figure 4 It is a partial structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0041] Figure 5 It is a partial structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0042] Figure 6 It is a partial structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0043] Figure 7It is a partial structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0044] Figure 8 It is a partial structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0045] Fig. 9 It is a partial structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0046] Fig.10 It is a partial structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0047] Fig.11 It is a partial structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0048] Fig.12 (a) and Fig.12 (b) are partial structural schematic diagrams of surface acoustic wave devices provided in different embodiments of the present application;

[0049] Fig.12 (c)-(f) are schematic diagrams of the structures of the widening parts provided in different embodiments of the present application;

[0050] Fig.13 It is a partial structural schematic diagram of a surface acoustic wave device provided by an embodiment of the present application;

[0051] Fig.14 is an admittance curve diagram of the surface acoustic wave device of comparative example 1;

[0052] Fig.15 is an admittance curve diagram of the surface acoustic wave device of Comparative Example 2;

[0053] Fig.16 is an admittance curve diagram of a surface acoustic wave device provided in one embodiment of the present application;

[0054] Fig.17 It is a comparison diagram of the real part of admittance curves of the surface acoustic wave device provided in one embodiment of the present application and the surface acoustic wave device of the comparative example.

[0055] Description of reference numerals:

[0056] 1000. Surface acoustic wave devices;

[0057] 100, piezoelectric substrate; 101, substrate; 102, piezoelectric film;

[0058] 200, interdigital transducer;

[0059] 10. bus bar; 11. first bus bar; 12. second bus bar;

[0060] 20, electrode finger; 201, first electrode finger; 202, second electrode finger; 21, widened portion;

[0061] 30. Fake finger; 31. First fake finger; 32. Second fake finger;

[0062] 300, reflective structure; 400, auxiliary structure; 401, auxiliary block; 500, dielectric layer;

[0063] A1, intersection area; A11, middle area; A12, edge area; B1, gap area. DETAILED DESCRIPTION

[0064] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0065] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0066] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, the singular forms "a", "an" and "the" are intended to include plural forms unless the context clearly indicates otherwise.

[0067] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0068] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0069] See also Figure 1 and Figure 2 The embodiment of the present application provides a surface acoustic wave device 1000, including a piezoelectric substrate 100 and an IDT 200, wherein the IDT 200 is disposed on the piezoelectric substrate 100. The IDT 200 cooperates with the piezoelectric substrate 100 to convert an electrical signal into an acoustic wave or convert an acoustic wave into an electrical signal. Exemplarily, the surface acoustic wave device 1000 may also include a reflection structure 300, which may be disposed on two opposite sides of the IDT 200. Specifically, in the direction of acoustic wave propagation, the reflection structure 300 is disposed on two opposite sides of the IDT 200. The reflection structure 300 is used to reflect the acoustic wave and confine the acoustic wave to the area where the IDT 200 is located.

[0070] Exemplarily, the surface acoustic wave device 1000 may include a surface acoustic wave resonator. The surface acoustic wave resonator may be a normal-SAW, a temperature-compensated surface acoustic wave resonator (TC-SAW), a surface acoustic wave resonator with a multi-layer substrate structure, or a transversely excited thin film bulk acoustic wave resonator.

[0071] In some embodiments, the material of the piezoelectric substrate 100 may specifically include at least one of quartz, aluminum nitride, sapphire, LN (lithium niobate, LiNbO3), LT (lithium tantalate, LiTaO3), etc., which is not specifically limited in this embodiment.

[0072] In some embodiments, the material of the IDT 200 may be a single metal material or a composite or alloy material of different metals. Optionally, the material of the IDT 200 may be aluminum, molybdenum, copper, gold, platinum, silver, nickel, chromium, tungsten, or a composite of the above metals or one of their alloys.

[0073] See also Figure 2 and Figure 3 The IDT 200 includes a bus bar 10 and electrode fingers 20. The number of the bus bars 10 includes two. In the arrangement direction of the two bus bars 10 of the IDT 200, there is a crossover area A1 between the two bus bars 10. The crossover area A1 includes a middle area A11 and edge areas A12 located on both sides of the middle area A11. In the arrangement direction of the electrode fingers 20 of the IDT 200, the crossover area A1 is an area where the electrode fingers 20 overlap with each other.

[0074] For example, the bus bar 10 and the electrode fingers 20 may be prepared simultaneously in one process or in different processes, which is not specifically limited in this embodiment.

[0075] See also Figure 3 In some embodiments, the two bus bars 10 are respectively the first bus bar 11 and the second bus bar 12, the first bus bar 11 and the second bus bar 12 are arranged at intervals on the piezoelectric substrate 100 along the first direction, and the first bus bar 11 and the second bus bar 12 are respectively connected to a plurality of electrode fingers 20. Each electrode finger 20 includes a first electrode finger 201 and a second electrode finger 202, the first electrode finger 201 is connected to the first bus bar 11, and the second electrode finger 202 is connected to the second bus bar 12, the first electrode finger 201 and the second electrode finger 202 are arranged at intervals along the second direction, and the first direction is perpendicular to the second direction. Exemplarily, the first electrode finger 201 and the second electrode finger 202 are arranged alternately and at intervals in sequence along the second direction. Exemplarily, the first direction being perpendicular to the second direction means that the first direction is perpendicular to the second direction on the plane where the piezoelectric substrate 100 is located. Exemplarily, the first direction is the arrangement direction of the two bus bars 10 or the length extension direction of the electrode fingers 20, and the second direction is the direction of sound wave propagation or the arrangement direction of each electrode finger 20. For example, the first direction or the arrangement direction of the two bus bars 10 is as follows: Figure 3 As shown in the X direction in FIG. 1 , the second direction or the arrangement direction of each electrode finger 20 is as shown in FIG. Figure 3 As shown in the Y direction.

[0076] Exemplarily, the top-view direction in this embodiment is perpendicular to the first direction and the second direction. Exemplarily, the interdigital transducer 200 is disposed on the upper surface of the piezoelectric substrate 100, and the "top-view direction" refers to a direction perpendicular to the upper surface of the piezoelectric substrate 100 and looking down on the piezoelectric substrate 100 from top to bottom. The term "top-view direction" has the same meaning in each embodiment and will not be described in detail in subsequent embodiments.

[0077] In other embodiments, the length direction of the bus bar 10 may also intersect with the second direction, as long as it is not parallel to the first direction. The length direction of each electrode finger 20 may be parallel to the first direction.

[0078] See also Figure 3, illustratively, each electrode finger 20 is arranged between the first bus bar 11 and the second bus bar 12; in the first direction, one end of the first electrode finger 201 is connected to the first bus bar 11, and the other end of the first electrode finger 201 is spaced from the second bus bar 12; one end of the second electrode finger 202 is connected to the second bus bar 12, and the other end of the second electrode finger 202 is spaced from the first bus bar 11. It can be understood that the end of each first electrode finger 201 close to the second bus bar 12 may be flush or uneven, and the end of each second electrode finger 202 close to the first bus bar 11 may be flush or uneven. In the second direction, the width of each electrode finger 20 may be the same or different. In the second direction, the width of the acceleration portion 21 of each electrode finger 20 may be the same or different.

[0079] See also Figure 3 , a cross region A1 and gap regions B1 located at both ends of the cross region A1 in the first direction are formed between the two bus bars 10. It can be understood that the region between the first electrode finger 201 and the second bus bar 12 and the region between the second electrode finger 202 and the first bus bar 11 are both gap regions B1.

[0080] See also Figure 3 In some embodiments, the surface acoustic wave device 1000 further includes an auxiliary structure 400, which is located in the edge area A12; the electrode finger 20 includes a widening portion 21 located in the edge area A12. In the same edge area A12, the projections of the widening portion 21 and the auxiliary structure 400 in the top view direction are at least partially staggered along the length extension direction of the electrode finger 20, and the acoustic impedance of the area where the widening portion 21 is provided is different from the acoustic impedance of the area where the auxiliary structure 400 is provided.

[0081] In the surface acoustic wave device 1000 of the above-mentioned embodiment, at the same edge area A12 of the interdigital transducer 200 of the surface acoustic wave device 1000, the projections of the widened portion 21 and the auxiliary structure 400 in the top view direction are at least partially staggered along the length extension direction of the electrode finger 20; in the same edge area A12, the acoustic impedance of the area provided with the widened portion 21 is different from the acoustic impedance of the area provided with the auxiliary structure 400, and by projecting the widened portion 21 and the auxiliary structure 400 in the top view direction along the electrode finger 20 in the same edge area A12 The length extension direction of the widened portion 20 is at least partially staggered to adjust the acoustic impedance of the edge area A12, so that the acoustic impedance of the area with the widened portion 21 is different from the acoustic impedance of the area with the auxiliary structure 400, so that the surface acoustic wave device 1000 can better suppress both the high-order lateral mode and the low-order lateral mode, so that the lateral mode of the surface acoustic wave device 1000 can be effectively suppressed, and the adverse effect of the lateral mode on the surface acoustic wave device 1000 can be reduced as much as possible, and energy leakage can be effectively prevented. In addition, the surface acoustic wave device 1000 of the embodiment of the present application is not easily affected by the spacing distance of adjacent electrode fingers 20 along the second direction during device manufacturing by staggering the widened portion 21 and the auxiliary structure 400, and can be applied to a higher frequency band. In addition, this embodiment can also reduce the occurrence of quality problems such as the spacing distance between adjacent electrode fingers 20 is too small and difficult to process or easy to process short circuits, and compared with two additional structures 400 with different thicknesses, it can reduce the process steps and reduce costs. The surface acoustic wave device 1000 of the embodiment of the present application has a reasonable structural design, is easy to process, and has a good lateral mode suppression effect.

[0082] In some embodiments, in the intersection area A1, the average value of the acoustic impedance of the area with the widened portion 21 and the acoustic impedance of the area with the auxiliary structure 400 is E; E is less than the acoustic impedance of the middle area A11. Exemplarily, in the same edge area A12, the projections of the widened portion 21 and the auxiliary structure 400 in the top view direction are at least partially staggered along the length extension direction of the electrode finger 20, so that in the same edge area A12, the acoustic impedance of the area with the widened portion 21 is different from the acoustic impedance of the area with the auxiliary structure 400; and the average value E of the acoustic impedance of the two structures is less than the acoustic impedance of the middle area A11, which can ensure that the surface acoustic wave device 1000 can effectively suppress high-order transverse modes and low-order transverse modes, and then can fully suppress the transverse modes, and has a good transverse mode suppression effect.

[0083] In some embodiments, in the same edge region A12, the acoustic impedance of the region provided with the widened portion 21 is less than the acoustic impedance of the region not provided with the auxiliary structure 400 and the widened portion 21. Exemplarily, in the same edge region A12, the projections of the widened portion 21 and the auxiliary structure 400 in the top view direction are at least partially staggered along the length extension direction of the electrode finger 20, so that in the same edge region A12, the acoustic impedance of the region provided with the widened portion 21 is different from the acoustic impedance of the region provided with the auxiliary structure 400. In the same edge area A12, when the projections of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top-view direction are arranged at intervals along the length extension direction of the electrode finger 20; or, in addition to the area with the widened portion 21 or the auxiliary structure 400, there are also areas without the widened portion 21 and the auxiliary structure 400, the area with the widened portion 21 has a smaller acoustic impedance than the area without the auxiliary structure 400 and the widened portion 21, and a larger acoustic impedance difference can be formed in the edge area A12, so as to achieve the suppression effect of the lateral mode of the surface acoustic wave device with a higher resonance frequency, and realize a high-frequency filter.

[0084] In some embodiments, in the same edge region A12, the acoustic impedance of the region provided with the auxiliary structure 400 is less than the acoustic impedance of the region not provided with the auxiliary structure 400 and the widening portion 21. Exemplarily, in the same edge region A12, the projections of the widening portion 21 and the auxiliary structure 400 in the top view direction are at least partially staggered along the length extension direction of the electrode finger 20, so that in the same edge region A12, the acoustic impedance of the region provided with the widening portion 21 is different from the acoustic impedance of the region provided with the auxiliary structure 400. In the same edge area A12, when the projections of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top-view direction are arranged at intervals along the length extension direction of the electrode finger 20; or, in addition to the area with the widened portion 21 or the auxiliary structure 400, there are also areas without the widened portion 21 and the auxiliary structure 400, the area with the auxiliary structure 400 has a smaller acoustic impedance than the area without the auxiliary structure 400 and the widened portion 21, and a larger acoustic impedance difference can be formed in the edge area A12, so as to achieve the suppression effect of the lateral mode of the surface acoustic wave device with a higher resonant frequency, and realize a high-frequency filter.

[0085] In some embodiments, the acoustic impedance of the region provided with the auxiliary structure 400 is less than the acoustic impedance of the region provided with the widened portion 21. The region provided with the auxiliary structure 400 has a lower acoustic impedance than the region provided with the widened portion 21, so that an undulating acoustic impedance distribution can be formed in the edge region A12, which can achieve a large acoustic impedance difference between the two, and can achieve the suppression of the lateral mode of the surface acoustic wave device with a higher resonance frequency, and realize a high-frequency filter.

[0086] In some embodiments, the acoustic impedance of the widened portion 21 and the auxiliary structure 400 closer to the middle area A11 is greater than the acoustic impedance of the other farther away from the middle area A11, so that a fluctuating acoustic impedance distribution can be formed in the edge area A12 to better suppress high-order transverse modes and low-order transverse modes and improve the performance of the surface wave device. For example, see Figure 3 , in the first direction, the widened portion 21 is closer to the middle area A11 than the auxiliary structure 400, and by adjusting the width of the widened portion 21 and the material and thickness of the auxiliary structure 400, the acoustic impedance of the area F1 provided with the widened portion 21 is greater than the acoustic impedance of the area F2 provided with the auxiliary structure 400; in addition, the acoustic impedance of the middle area A11 is greater than the acoustic impedance of the area F1 provided with the widened portion 21, and the acoustic impedance of the gap area B1 is greater than the acoustic impedance of the area F2 provided with the auxiliary structure 400, thereby achieving effective suppression of low-order lateral modes and high-order lateral modes, and effectively improving the performance of the surface acoustic wave device 1000. Exemplarily, when the widened portion 21 is closer to the middle area A11 than the auxiliary structure 400 in the first direction, the edge area A12 may be the maximum spacing area between the widened portion 21 of the electrode finger 20 and the finger end of the electrode finger 20 in the first direction, such as Figure 3 As shown in A12 in .

[0087] For example, in the first direction, the auxiliary structure 400 is closer to the middle area A11 than the widened portion 21, for example Figure 7 . Exemplarily, in the same edge area A12, the widening portion 21 is adjacent to the auxiliary structure 400, the widening portion 21 is farther away from the middle area A11 than the auxiliary structure 400, the acoustic impedance of the area provided with the auxiliary structure 400 is greater than the acoustic impedance of the area provided with the widening portion 21, the acoustic impedance of the middle area A11 is greater than the acoustic impedance of the area provided with the auxiliary structure 400, and the acoustic impedance of the gap area B1 is greater than the acoustic impedance of the area provided with the widening portion 21, thereby achieving effective suppression of low-order lateral modes and high-order lateral modes, and effectively improving the performance of the surface acoustic wave device 1000. Exemplarily, when the auxiliary structure 400 is closer to the middle area A11 than the widening portion 21 in the first direction, the edge area A12 may be the area in the first direction between the projection of the auxiliary structure 400 on the plane where the interdigital transducer 200 is located and the bus bar 11 (including the area corresponding to the auxiliary structure 400).

[0088] Exemplarily, in the arrangement direction of the two bus bars 10, the projection of the auxiliary structure 400 in the top view direction can completely cover the gap area B1. In some embodiments, in the top view direction, the electrode finger 20 can also be appropriately exposed from the auxiliary structure 400 in the arrangement direction of the two bus bars 10. Exemplarily, the length of the exposed portion is much smaller than the length of the portion covered by the auxiliary structure 400. Exemplarily, in the arrangement direction of the two bus bars 10, the projection of the auxiliary structure 400 in the top view direction is flush with or closer to the middle area A11 than the end of the electrode finger 20 away from the connected bus bar 10.

[0089] It is understandable that the length and / or width of the widened portion 21 can be adjusted to adjust the acoustic impedance of the area where the widened portion 21 is located, and cooperate with the auxiliary structure 400 to achieve good high-order lateral mode suppression effect and good low-order lateral mode suppression effect. Similarly, the widened portion 21 can be cooperated with by reasonably designing at least one of the length of the auxiliary structure 400 along the arrangement direction of the two busbars 10 and the thickness along the top view direction to achieve good high-order lateral mode suppression effect and good low-order lateral mode suppression effect. Please refer to Figure 3 , exemplarily, in the arrangement direction of each busbar 10, an edge area A12 is provided on each side of the middle area A11, wherein the widened portion 21 at one edge area A12 and the widened portion 21 at another edge area A12 can be arranged axially symmetrically or non-axially symmetrically; the auxiliary structure 400 at one edge area A12 and the auxiliary structure 400 at another edge area A12 can be arranged axially symmetrically or non-axially symmetrically. For example, the size of at least one of the widened portion 21 and the auxiliary structure 400 on both sides of the same electrode finger 20 can be different, or the position of at least one of the widened portion 21 and the auxiliary structure 400 on both sides of the same electrode finger 20 can be different. Exemplarily, the shape of the cross area A1 (i.e., the aperture of the interdigital transducer 200) can be any suitable shape such as a rectangle or a wave. The shape of the intersection area A1 can be made non-rectangular (i.e., a shape other than a rectangle) by at least one of the following methods: adjusting at least one of the position and shape of the widened portion 21 and / or the auxiliary structure 400 at the edge area A12; designing the middle area A11 to be a shape other than a rectangle.

[0090] See also Figure 4 In some embodiments, the length of the widened portion 21 along the arrangement direction of the two bus bars 10 is L 2 , 0 <L 2 <2.8λ, where λ is the period of the electrode finger 20. For example, L 2 L is 0.1λ, 0.5λ, 1λ, 1.5λ, 2λ, 2.7λ or any other suitable value in the range of 0-2.8λ. 2Within this range, processing is easy and convenient, the qualified rate of processed products is high, and high-order lateral modes and low-order lateral modes can be effectively suppressed.

[0091] In some embodiments, the thickness of the widened portion 21 is equal to the thickness of the electrode finger 20 located in the middle area A11. In this way, the widened portion 21 and the electrode finger 20 can be processed in the same process, and the processing of the surface acoustic wave device 1000 is simple, easy, and efficient. In other embodiments, the widened portion 21 can also be processed in different processing techniques from the electrode finger 20 located in the middle area A11. The thickness of the widened portion 21 can also be different from the thickness of the electrode finger 20 located in the middle area A11.

[0092] See also Figure 4 In some embodiments, the width of the auxiliary structure 400 along the arrangement direction of each electrode finger 20 is W 1 The width of the electrode finger 20 along the arrangement direction of each electrode finger 20 is W 3 , W 1 ≥W 3 / 2, in this way, the high-order lateral modes and the low-order lateral modes can be effectively suppressed, and the processing is easy and convenient.

[0093] For example, the length of the widened portion 21 along the arrangement direction of the two bus bars 10 is L 2 , 0 <L 2 <2.8λ, λ is the period of the electrode finger 20; the width of the auxiliary structure 400 along the arrangement direction of each electrode finger 20 is W 1 The width of the electrode finger 20 along the arrangement direction of each electrode finger 20 is W 3 , W 1 ≥W 3 / 2, thus, the high-order transverse modes and the low-order transverse modes can be more effectively suppressed; and the processing of the surface acoustic wave device 1000 is easier and more convenient.

[0094] See also Figure 4 In some embodiments, the length of the auxiliary structure 400 along the arrangement direction of the two bus bars 10 is L 1 , 0.01λ <L 1 <2.6λ, where λ is the period of the electrode finger 20. For example, L 1 L is 0.02λ, 0.5λ, 1λ, 1.5λ, 2λ, 2.5λ or any other suitable value in the range of 0.01λ-2.6λ. 1 Within this range, processing is easy, the qualified rate of processed products is high, and high-order lateral modes and low-order lateral modes can be effectively suppressed.

[0095] In some embodiments, the thickness of the auxiliary structure 400 is H 1, 0.002λ <H 1 <2λ, where λ is the period of the electrode finger 20. For example, H 1 H is 0.003λ, 0.01λ, 0.5λ, 1λ, 1.5λ, 1.9λ or any other suitable value between 0.002λ and 2λ. 1 Within this range, the processing is easy and convenient, the qualified rate of the processed products is high, and the high-order lateral modes and low-order lateral modes can be effectively suppressed. The thickness of the auxiliary structure 400 refers to the thickness of the auxiliary structure 400 along the top view direction. For example, 0.01λ <L 1 <2.6λ, 0.002λ <H 1 <2λ, so that the processing of the surface acoustic wave device 1000 is easier and more convenient, and the high-order transverse modes and the low-order transverse modes can be fully and effectively suppressed.

[0096] For example, the length of the auxiliary structure 400 along the arrangement direction of the two bus bars 10 is L 1 , 0.01λ <L 1 <2.6λ; the thickness of the auxiliary structure 400 is H 1 , 0.002λ <H 1 <2λ, λ is the period of the electrode finger 20, so that the high-order transverse mode and the low-order transverse mode can be effectively suppressed as much as possible, and the processing of the surface acoustic wave device 1000 is further made easier and more convenient.

[0097] See also Figure 4 In some embodiments, within the same edge region A12, the width of the widened portion 21 along the arrangement direction of each electrode finger 20 is W. 2 The width of the electrode finger 20 along the arrangement direction of each electrode finger 20 is W 3 , the center distance between two adjacent electrode fingers 20 is P 3 , W 3 ≤W 2 <(2P 3 -W 3 ). In this way, high-order lateral modes and low-order lateral modes can be effectively suppressed, and the processing is easy and convenient.

[0098] For example, the length of the widened portion 21 along the arrangement direction of the two bus bars 10 is L 2 , 0 <L 2 <2.8λ, λ is the period of the electrode finger 20; the width of the auxiliary structure 400 along the arrangement direction of each electrode finger 20 is W 1 The width of the electrode finger 20 along the arrangement direction of each electrode finger 20 is W 3 , W 1 ≥W 3 / 2; the length of the auxiliary structure 400 along the arrangement direction of the two bus bars 10 is L 1 , 0.01λ <L 1 <2.6λ; the thickness of the auxiliary structure 400 is H 1 , 0.002λ <H 1 <2λ, thus, the high-order transverse modes and the low-order transverse modes can be effectively suppressed to the greatest extent, further making the processing of the surface acoustic wave device 1000 easier and more convenient.

[0099] See also Figure 3 In some embodiments, in the same edge region A12, the projections of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top-view direction are adjacent to each other along the length extension direction of the electrode finger 20. That is to say, in the same edge region A12, the projections of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top-view direction are adjacent to each other in the first direction and the projections of the two are in contact in the first direction. In this way, the surface acoustic wave device 1000 can better suppress both high-order transverse modes and low-order transverse modes, thereby better suppressing transverse modes; and can save materials and reduce costs. It can be understood that within a reasonable processing error range, in the same edge region A12, the projections of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top-view direction are adjacent to each other along the length extension direction of the electrode finger 20.

[0100] See also Figure 5 In other embodiments, within the same edge area A12, the projections of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top view direction are arranged at intervals along the length extension direction of the electrode finger 20, thereby allowing a certain process tolerance, strong operability, low process cost, and improving product yield; and better suppressing abutment lateral modes and high-order lateral modes.

[0101] See also Figure 6 In some other embodiments, within the same edge area A12, the projections of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top-view direction partially overlap along the length extension direction of the electrode finger 20, thereby allowing a certain process tolerance, strong operability, low process cost, and improved product yield; and can better suppress abutting transverse modes and high-order transverse modes. Exemplarily, within the same edge area A12, the acoustic impedance of the area where the projections of the auxiliary structure 400 and the widened portion 21 in the top-view direction overlap is smaller than the acoustic impedance of the remaining parts, forming such an acoustic impedance distribution, which can better suppress high-order transverse modes and low-order transverse modes, thereby first suppressing the transverse modes during the leakage of sound waves from the intersection area A1 to the gap area B1. Exemplarily, please refer to Figure 6The offset lengths of the widened portion 21 and the auxiliary structure 400 are much greater than the length of the overlapping portion thereof. The offset lengths of the widened portion 21 and the auxiliary structure 400 refer to the lengths of the widened portion 21 and the auxiliary structure 400 along the length extension direction of the electrode finger 20 .

[0102] See also Figure 5 In some embodiments, within the same edge region A12, the projection of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top view direction is spaced by a preset distance L along the length extension direction of the electrode finger 20. 3 , L 3 <2.6λ, where λ is the period of electrode finger 20. For example, see Figure 5 In the same edge area A12, the projection of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top view direction is spaced along the length extension direction of the electrode finger 20, and the spacing distance between the two is L 3 , L 3 <2.6λ, thus, the dimension of the surface acoustic wave device 1000 along the length extension direction of the electrode finger 20 can be made as small as possible under the premise of ensuring good suppression of high-order transverse modes and low-order transverse modes, which is conducive to miniaturization of the product and reduction of cost. For example, the dimension of the widened portion 21 along the length extension direction of the electrode finger 20 is greater than L 3 The dimension of the auxiliary structure 400 along the length extension direction of the electrode finger 20 is greater than L 3 .

[0103] See also Figure 6 In some embodiments, in the same edge area A12, the projection of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top view direction overlaps by a preset distance L along the length extension direction of the electrode finger 20. 4 , L 4 <2.6λ, where λ is the period of the electrode finger 20. For another example, see Figure 6 In the same edge area A12, the projections of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top view direction partially overlap along the length extension direction of the electrode finger 20, and the overlapping distance between the two is L 4 , L 4<2.6λ, thus, the dimensions of the widening portion 21 and the auxiliary structure 400 along the length extension direction of the electrode finger 20 can be reduced under the premise of ensuring good suppression of high-order lateral modes and low-order lateral modes, which is conducive to miniaturization of the product and cost reduction. Exemplarily, in the same edge area A12, the widening portion 21 includes a first staggered area, and the first staggered area corresponding to the same electrode finger 20 is adjacent to and staggered with the projection of the auxiliary structure 400 in the top view direction, and the dimension of the first staggered area along the length extension direction of the electrode finger 20 is greater than L 4 The auxiliary structure 400 includes a second staggered area, the second staggered area corresponding to the same electrode finger 20 is adjacent to the projection of the widened portion 21 in the top view direction and is staggered, and the size of the second staggered area along the length extension direction of the electrode finger 20 is greater than L 4 .

[0104] See also Figure 3In some embodiments, in the same edge region A12, the widened portion 21 is closer to the middle region A11 than at least part of the attached structure 400, so as to take into account the ease of processing, good high-order lateral mode suppression effect and good low-order mode suppression effect. For example, in the same edge region A12, the projection of the widened portion 21 and the attached structure 400 corresponding to the same electrode finger 20 in the top view direction is adjacent along the length extension direction of the electrode finger 20, and the widened portion 21 is closer to the middle region A11 than the attached structure 400. For example, in the same edge region A12, the widened portion 21 is closer to the middle region A11 than the attached structure 400, so that the acoustic impedance of the region provided with the widened portion 21 is greater than the acoustic impedance of the region provided with the attached structure 400. It is possible to achieve a structure in which the acoustic impedance difference of the two regions can be adjusted within a larger range, thereby improving the suppression effect of high-order transverse modes and abutting transverse modes, and making the width of the widened portion 21 (located on the inner side of the edge region A12) relatively small, so that the widened portion 21 has less influence on the resonant frequency of the device, so that the spacing between the electrode fingers 20 of the device can be made smaller, so that the device can be suitable for filters in higher frequency bands. Therefore, it is possible to achieve better suppression effects on both high-order transverse modes and low-order transverse modes at higher frequency bands. It can be understood that the widened portion 21 is closer to the middle area A11 than at least part of the subsidiary structure 400, including at least one of the following situations: situation a), in the same edge area A12, the projections of the widened portion 21 and the subsidiary structure 400 corresponding to the same electrode finger 20 in the top view direction partially overlap along the length extension direction of the electrode finger 20, and the widened portion 21 is closer to the middle area A11 than the part of the subsidiary structure 400 that does not overlap with the widened portion 21. situation b), in the same edge area A12, the projections of the widened portion 21 and the subsidiary structure 400 corresponding to the same electrode finger 20 in the top view direction are adjacent or spaced along the length extension direction of the electrode finger 20, and the widened portion 21 is closer to the middle area A11 than the subsidiary structure 400.

[0105] For example, in the same edge area A12, the projection of the widened portion 21 and the auxiliary structure 400 corresponding to the same electrode finger 20 in the top view direction is adjacent along the length extension direction of the electrode finger 20, the widened portion 21 is closer to the middle area A11 than the auxiliary structure 400, and the length of the auxiliary structure 400 along the arrangement direction of the two bus bars 10 is L 1 , 0.01λ <L 1 <2.6λ; the thickness of the auxiliary structure 400 is H 1 , 0.002λ <H 1 <2λ; the length of the widened portion 21 along the arrangement direction of the two busbars 10 is L 2 , 0 <L 2 <2.8λ; the width of the widened portion 21 along the arrangement direction of each electrode finger 20 is W2 The width of the electrode finger 20 along the arrangement direction of each electrode finger 20 is W 3 , the center distance between two adjacent electrode fingers 20 is P 3 , W 3 ≤W 2 <(2P 3 / 2-W 3 ). In this way, the surface acoustic wave device 1000 can be easily and conveniently processed, and high-order transverse modes and low-order transverse modes can be suppressed as fully as possible.

[0106] See also Figure 7 In some embodiments, in the same edge area A12, the widened portion 21 is further away from the middle area A11 than at least part of the attached structure 400. Exemplarily, in the same edge area A12, the widened portion 21 is adjacent to the attached structure 400, and the widened portion 21 is further away from the middle area A11 than the attached structure 400.

[0107] See also Figure 8 In some embodiments, the auxiliary structure 400 includes a plurality of auxiliary blocks 401, and the auxiliary blocks 401 are arranged in sequence at intervals in the arrangement direction of the electrode fingers 20; the projection of each electrode finger 20 and an auxiliary block 401 in the top view direction at least partially overlaps. That is, along the arrangement direction of the electrode fingers 20, the auxiliary structure 400 is intermittently arranged. In this way, on the basis of ensuring a good high-order transverse mode suppression effect and a low-order transverse mode suppression effect, the auxiliary structure 400 uses less material, which can reduce the weight of the auxiliary structure 400 to reduce the weight of the surface acoustic wave device 1000, which is conducive to achieving lightweight and cost reduction of the product. It can be understood that the overlapping area of ​​the projection of each electrode finger 20 and the corresponding auxiliary block 401 in the top view direction can be the same or different. The sizes of the two in the arrangement direction of each electrode finger 20 can be the same or different. For the same auxiliary structure 400, the lengths of the auxiliary blocks 401 included therein along the arrangement direction of the two bus bars 10 may be the same or different; the widths of the auxiliary blocks 401 included therein along the arrangement direction of the electrode fingers 20 may be the same or different; the thicknesses of the auxiliary blocks 401 included therein may be the same or different. Exemplarily, the length, width and thickness of each auxiliary block 401 are convenient for manufacturing in the same process to reduce process costs. In some embodiments, each auxiliary block 401 overlaps with the corresponding electrode finger 20 in the arrangement direction of each electrode finger 20.

[0108] See also Figure 3In some embodiments, the projection of the auxiliary structure 400 and each electrode finger 20 in the top view direction overlaps in the arrangement direction of each electrode finger 20, and overlaps with the projection of the gap between any two adjacent electrode fingers 20 in the top view direction. That is, along the arrangement direction of each electrode finger 20, the auxiliary structure 400 is continuously and uninterruptedly arranged, so that the auxiliary structure 400 is simple and convenient to process while ensuring a good high-order transverse mode suppression effect and a low-order transverse mode suppression effect.

[0109] See also Fig. 9 In some embodiments, the auxiliary structure 400 is disposed on the side of the IDT 200 facing the piezoelectric substrate 100, so that the auxiliary structure 400 can be manufactured in the same process, which can reduce the process steps and reduce the cost. Fig.10 In some embodiments, the auxiliary structure 400 is disposed on the side of the IDT 200 away from the piezoelectric substrate 100, so that the auxiliary structure 400 can be manufactured in the same process, which can reduce the process steps and reduce the cost; in addition, the auxiliary structure 400 is disposed on the side of the IDT 200 away from the piezoelectric substrate 100, and the auxiliary structure 400 and the IDT 200 are easy and convenient to process, and the surface acoustic wave device 1000 is simple and convenient to process. In some other embodiments, one part of the auxiliary structure 400 is disposed on the side of the IDT 200 facing the piezoelectric substrate 100, and the other part of the auxiliary structure 400 is disposed on the side of the IDT 200 away from the piezoelectric substrate 100.

[0110] See also Fig.10 In some embodiments, in the top view direction, the auxiliary structure 400 is arranged in close contact with the electrode finger 20. Fig.11 In some embodiments, in the top view direction, the auxiliary structure 400 is spaced apart from the electrode finger 20, which is beneficial for balancing the ease of processing and the reliability of the product.

[0111] The shapes of the auxiliary structure 400, the auxiliary block 401 and / or the widened portion 21 can be designed according to actual needs and are not limited here. Figure 4 as shown in the strips in Fig.12 (a) or 12 (b); or any other suitable regular shape or irregular shape. For example, the shape of the widened portion 21 is as follows Figure 4 The square in the figure; or Fig.12 Any shape as shown in (c)-12(f); or any other suitable regular shape or irregular shape.

[0112] For example, the widened portion 21 can be manufactured together with the electrode finger 20 in the same process, and the auxiliary structure 400 can be manufactured in another process. The auxiliary structure 400 can be manufactured together in the same process. Compared with the solution of manufacturing the auxiliary structure 400 in two different processes to achieve the acoustic impedance difference, this embodiment can reduce the manufacturing process of the surface acoustic wave device 1000.

[0113] The accessory structure 400 may be a single metal or a composite or alloy of different metals. For example, the material of the accessory structure 400 may be one of molybdenum, tungsten, ruthenium, gold, magnesium, aluminum, copper, chromium, titanium, osmium, iridium or a composite or alloy of the above metals. Of course, the material of the accessory structure 400 may also be a dielectric, such as tantalum oxide. In some embodiments, the accessory structure 400 is a conductive structure or a non-conductive structure. The conductive structure may include a structure made of a conductive metal. The material of the non-conductive structure may include silicon dioxide or any other suitable material.

[0114] In some embodiments, the auxiliary structure 400 is a conductive structure, and the auxiliary structure 400 includes an auxiliary block 401. In the arrangement direction of each electrode finger 20, each auxiliary block 401 is arranged in sequence and spaced apart; in the top view direction, each electrode finger 20 is arranged in contact with an auxiliary block 401; the surface acoustic wave device 1000 also includes a dielectric layer 500 (see Fig.11 ), a dielectric layer 500 is disposed on the piezoelectric substrate 100, and the dielectric layer 500 covers the interdigital transducer 200 and the auxiliary structure 400. The surface acoustic wave device 1000 of this structure has a reasonable structural design, is easy, convenient and simple to process, and has a good lateral modal suppression effect. Exemplarily, the auxiliary structure 400 is a conductive structure; in the top view direction, each electrode finger 20 is arranged in contact with an auxiliary block 401, and the electrode finger 20 and the auxiliary block 401 can be manufactured in the same process. For example, the electrode finger 20 and the auxiliary block 401 are both manufactured by a coating process, and the electrode finger 20 and the auxiliary block 401 do not need to be manufactured using two different processes, so that the surface acoustic wave device 1000 is simple, convenient and easy to process.

[0115] In some embodiments, the auxiliary structure 400 is a non-conductive structure; in the top view direction, the auxiliary structure 400 is arranged in close contact with the IDT 200. Exemplarily, the auxiliary structure 400 overlaps with the projection of each electrode finger 20 in the top view direction, and overlaps with the projection of the gap between any two adjacent electrode fingers 20 in the top view direction, that is, the auxiliary structure 400 is a continuous and uninterrupted strip structure, and in the top view direction, the auxiliary structure 400 is in close contact with the IDT 200, and the auxiliary structure 400 is a non-conductive structure.

[0116] In other embodiments, the auxiliary structure 400 can be a conductive structure or a non-conductive structure. For example, in the top view direction, a dielectric layer 500 is provided between the auxiliary structure 400 and the interdigital transducer 200; the auxiliary structure 400 is a non-conductive structure, and the surface acoustic wave device 1000 of such a structure is easy, convenient, and simple to process, and has a good high-order lateral mode and low-order lateral mode suppression effect. Exemplarily, in the top view direction, a dielectric layer 500 is provided between the auxiliary structure 400 and the interdigital transducer 200, and the auxiliary structure 400 and the interdigital transducer 200 are manufactured separately, for example, the auxiliary structure 400 is manufactured by an etching process or a stripping process, and the interdigital transducer 200 is manufactured by a coating process; the auxiliary structure 400 is a non-conductive structure, which is convenient for the manufacture of the auxiliary structure 400 and / or the interdigital transducer 200, thereby making the processing of the surface acoustic wave device 1000 simple, convenient, and easy.

[0117] See also Fig.11 In some embodiments, the surface acoustic wave device 1000 further includes a dielectric layer 500, the dielectric layer 500 covers the IDT 200, and the dielectric layer 500 is disposed on a side of the electrode finger 20 away from the piezoelectric substrate 100. The dielectric layer 500 can protect the IDT 200 and / or the accessory structure 400. Exemplarily, the dielectric layer 500 covers the IDT 200 and the accessory structure 400. The dielectric layer 500 may completely cover the IDT 200, or may not completely cover the IDT 200, for example, only covers the area where the electrode finger 20 of the IDT 200 is located, while the bus bar 10 is not covered.

[0118] In some embodiments, the dielectric layer 500 is a temperature compensation layer. The temperature compensation layer is used to improve the temperature characteristics of the surface acoustic wave device 1000, and the material of the temperature compensation layer can be a dielectric such as silicon oxide, silicon nitride, silicon oxynitride, etc. Among them, the material of the temperature compensation layer is usually one of the above materials, that is, the material of the temperature compensation layer is a single material. Of course, the material of the temperature compensation layer can also be a mixed material, in which case the material of the temperature compensation layer can be a mixture of any of the above materials, or a mixture of one or more of the above materials with other materials. In other embodiments, the dielectric layer 500 can also include at least one of the following: a frequency modulation layer and a passivation layer. The frequency modulation layer is used to adjust the frequency of the surface acoustic wave device 1000. The material of the frequency modulation layer can be at least one of silicon dioxide, silicon nitride, aluminum nitride, aluminum oxide, etc. The passivation layer is used to protect the interdigital transducer 200 and / or the auxiliary structure 400, etc. The material of the passivation layer can be at least one of silicon dioxide, silicon nitride, aluminum nitride, aluminum oxide, etc.

[0119] See also Fig.11In some embodiments, the auxiliary structure 400 is disposed on a side of the dielectric layer 500 away from the electrode finger 20. Exemplarily, in the top view direction, at least part of the dielectric layer 500 is disposed between the auxiliary structure 400 and the electrode finger 20, that is, the auxiliary structure 400 and the electrode finger 20 are spaced apart in the top view direction, and the dielectric layer 500 is filled between the auxiliary structure 400 and the electrode finger 20. Fig.10 In some embodiments, the dielectric layer 500 is disposed on a side of the auxiliary structure 400 away from the electrode finger 20 , that is, in a top view direction, the auxiliary structure 400 is disposed between the dielectric layer 500 and the electrode finger 20 .

[0120] See also Figure 2 In some embodiments, the piezoelectric substrate 100 includes a stacked substrate 101 and a piezoelectric film 102, and the interdigital transducer 200 is disposed on the surface of the piezoelectric film 102 away from the substrate 101. In this way, the Q value of the surface acoustic wave device 1000 can be improved and can be applied to higher frequency bands of 5G and above. Exemplarily, the material of the substrate 101 can be silicon.

[0121] See also Fig.13 In some embodiments, the IDT 200 further includes a dummy finger 30, one end of which is connected to one of the bus bars 10, and the other end of the dummy finger 30 is spaced apart from the end of the electrode finger 20 connected to the other bus bar 10. The provision of the dummy finger 30 can suppress the transverse modal interference of the surface acoustic wave device 1000, reduce energy leakage, and thus improve the Q value of the surface acoustic wave device 1000.

[0122] See also Fig.13 , exemplarily, the number of the dummy fingers 30 includes a plurality of dummy fingers 30, and the plurality of dummy fingers 30 include a first dummy finger 31 and a second dummy finger 32, one end of the first dummy finger 31 is connected to the first bus bar 11, and the other end of the first dummy finger 31 is spaced apart from the second electrode finger 202 in the arrangement direction of the two bus bars 10; one end of the second dummy finger 32 is connected to the second bus bar 12, and the other end of the second dummy finger 32 is spaced apart from the first electrode finger 201 in the arrangement direction of the two bus bars 10. The number of the first dummy fingers 31 and the number of the second dummy fingers 32 can be designed according to actual needs, such as one or more. Exemplarily, the number of the first dummy fingers 31 is a plurality of, and the end of each first dummy finger 31 away from the first bus bar 11 can be flush or uneven, and a first dummy finger 31 can be set between two adjacent first electrode fingers 201. There are multiple second dummy fingers 32 , and the ends of the second dummy fingers 32 facing away from the second bus bar 12 may be flush or uneven, and one second dummy finger 32 may be disposed between two adjacent second electrode fingers 202 .

[0123] It can be understood that when the surface acoustic wave device 1000 is provided with a first dummy finger 31 and a second dummy finger 32, the gap area B1 actually refers to the area between the first dummy finger 31 and the second electrode finger 202 in the arrangement direction of the two bus bars 10; or, the area between the second dummy finger 32 and the first electrode finger 201.

[0124] like Figure 14-16 As shown, the surface acoustic wave device 1000 according to the embodiment of the present application is compared with a surface acoustic wave device 1000 of a traditional structure.

[0125] Fig.14 1 is an admittance curve diagram of the surface acoustic wave device 1000 of comparative example 1, wherein the surface acoustic wave device 1000 of comparative example 1 is not provided with the widening portion 21 and the auxiliary structure 400 . Fig.14 The horizontal axis is the frequency in GHz, and the vertical axis is the admittance in dB. Fig.14 It can be seen that the surface acoustic wave device 1000 has a large lateral mode between the resonance point and the anti-resonance point.

[0126] Fig.15 1 is an admittance curve diagram of the surface acoustic wave device 1000 of comparative example 2, wherein the surface acoustic wave device 1000 of comparative example 2 is provided with only one of the widened portion 21 and the auxiliary structure 400 . Fig.15 The horizontal axis is frequency, in GHz; the vertical axis is admittance, in dB. Fig.15 The surface acoustic wave device 1000 in the embodiment can suppress the transverse mode by adjusting the structural features of the widened portion 21 or the auxiliary structure 400. Fig.15 The low-order lateral modes can be suppressed, but the suppression effect of high-order lateral modes is not ideal.

[0127] Fig.16 This is an admittance curve diagram of the surface acoustic wave device 1000 provided in one embodiment of the present application. Fig.16 The horizontal axis is the frequency in GHz, and the vertical axis is the admittance in dB. Fig.16 and Fig.14 , Fig.15 By comparison, it can be seen that in this embodiment, by simultaneously providing the widened portion 21 and the additional structure 400, the widened portion 21 and the additional structure 400 are at least partially offset, and the acoustic impedances of the two are different, which can better suppress both high-order lateral modes and low-order lateral modes.

[0128] Fig.17A comparison diagram of the real part of the admittance curve of the surface acoustic wave device 1000 provided in an embodiment of the present application and the surface acoustic wave device 1000 of the comparative example. The dotted line is the real part of the admittance curve of the surface acoustic wave device 1000 of the comparative example, and the solid line is the real part of the admittance curve of the surface acoustic wave device 1000 of the present embodiment. The comparative example is a real part of the admittance curve in which only one acoustic impedance is used in the related art, and the acoustic impedance is adjusted to achieve a better lateral mode suppression effect. Fig.17 The horizontal axis is the frequency in GHz, and the vertical axis is the real part of admittance in dB. Fig.17 By comparing the solid line and the dotted line, it can be seen that the high-order lateral modes and the low-order lateral modes of the surface acoustic wave device 1000 of the embodiment of the present application have been basically effectively suppressed, and the suppression effect on the lateral modes is good.

[0129] The embodiment of the present application also provides a surface acoustic wave device 1000, including a piezoelectric substrate 100, an IDT 200, an auxiliary structure 400 and a dielectric layer 500, wherein the IDT 200 is disposed on the piezoelectric substrate 100. In the arrangement direction of the two bus bars 10 of the IDT 200, there is a crossover region A1 between the two bus bars 10, and the crossover region A1 includes a middle region A11 and edge regions A12 located at both ends of the middle region A11; wherein, in the arrangement direction of the electrode fingers 20 of the IDT 200, the crossover region A1 is a region where the electrode fingers 20 overlap with each other. The electrode finger 20 includes a widened portion 21 located in the edge region A12; at least one of the two edge regions A12 is provided with a widened portion 21 and an auxiliary structure 400. In the same edge area A12, the projections of the widened portion 21 and the auxiliary structure 400 in the top view direction are at least partially staggered along the length extension direction of the electrode finger 20; the auxiliary structure 400 is a conductive structure, and the auxiliary structure 400 includes a plurality of auxiliary blocks 401, and in the arrangement direction of each electrode finger 20, each auxiliary block 401 is sequentially arranged at intervals; in the top view direction, each electrode finger 20 is arranged in contact with an auxiliary block 401. The dielectric layer 500 is provided on the piezoelectric substrate 100 and covers the interdigital transducer 200 and the auxiliary structure 400.

[0130] In the surface acoustic wave device 1000 of the above embodiment, at the same edge area A12 of the interdigital transducer 200 of the surface acoustic wave device 1000, the projections of the widening portion 21 and the auxiliary structure 400 in the top view direction are at least partially staggered along the length extension direction of the electrode finger 20, so as to adjust the acoustic impedance of the edge area A12, so that the acoustic impedance of the area with the widening portion 21 is different from the acoustic impedance of the area with the auxiliary structure 400, so that the surface acoustic wave device 1000 can better suppress both high-order transverse modes and low-order transverse modes, so as to effectively suppress the transverse modes of the surface acoustic wave device 1000, minimize the adverse effects of the transverse modes on the surface acoustic wave device 1000, and effectively prevent energy leakage. In addition, the surface acoustic wave device 1000 of the embodiment of the present application is not easily affected by the spacing distance of adjacent electrode fingers 20 along the second direction when the device is manufactured, and can be applied to a higher frequency band. In addition, this embodiment can also reduce the occurrence of quality problems such as the distance between adjacent electrode fingers 20 being too small and difficult to process or being easy to process short circuits, and compared with two additional structures 400 of different thicknesses, it can reduce the process steps and reduce costs. In addition, the solution of realizing the acoustic impedance difference of the corresponding two regions by using two additional structures 40 of different thicknesses requires multiple processing of the additional structures 400 of different thicknesses; compared with the solution of realizing the acoustic impedance difference of the corresponding two regions by using two additional structures 40 of different thicknesses, the surface acoustic wave device 1000 of this embodiment can reduce the processing technology and reduce the process cost.

[0131] In addition, since the surface acoustic wave device 1000 includes the auxiliary structure 400 and the dielectric layer 500, the auxiliary structure 400 is a conductive structure, and the auxiliary structure 400 includes a plurality of auxiliary blocks 401, and in the arrangement direction of each electrode finger 20, each auxiliary block 401 is arranged in sequence and spaced apart; in the top view direction, each electrode finger 20 is arranged in contact with an auxiliary block 401; the dielectric layer 500 is arranged on the piezoelectric substrate 100 and covers the interdigital transducer 200 and the auxiliary structure 400, so the surface acoustic wave device 1000 is easy, convenient and simple to process. The surface acoustic wave device 1000 of the embodiment of the present application has a reasonable structural design, is easy to process, and has a good lateral mode suppression effect.

[0132] Exemplarily, one of the two edge regions A12 is provided with a widened portion 21 and an auxiliary structure 400. Exemplarily, both edge regions A12 are provided with a widened portion 21 and an auxiliary structure 400 at the same time.

[0133] Exemplarily, the piezoelectric substrate 100 includes the piezoelectric substrate 100 of any of the above embodiments. The IDT 200 includes the IDT 200 of any of the embodiments of the present application. The auxiliary structure 400 includes the auxiliary structure 400 of any of the above embodiments. The dielectric layer 500 includes the dielectric layer 500 of any of the above embodiments.

[0134] The embodiment of the present application also provides a surface acoustic wave device 1000, including a piezoelectric substrate 100, an IDT 200 and an auxiliary structure 400; the IDT 200 is arranged on the piezoelectric substrate 100; in the arrangement direction of the two bus bars 10 of the IDT 200, there is a crossover area A1 between the two bus bars 10, and the crossover area A1 includes a middle area A11 and edge areas A12 located at both ends of the middle area A11; wherein, in the arrangement direction of each electrode finger 20 of the IDT 200, the crossover area A1 is an area where each electrode finger 20 overlaps with each other. The electrode finger 20 includes a widened portion 21 located in the edge area A12, and at least one of the two edge areas A12 is provided with the widened portion 21 and the auxiliary structure 400. Among them, in the same edge area A12, the projections of the widened portion 21 and the auxiliary structure 400 in the top-view direction are at least partially staggered along the length extension direction of the electrode finger 20; the auxiliary structure 400 is a non-conductive structure; in the top-view direction, a dielectric layer 500 is provided between the auxiliary structure 400 and the interdigital transducer 200.

[0135] In the surface acoustic wave device 1000 of the above embodiment, at the same edge area A12 of the interdigital transducer 200 of the surface acoustic wave device 1000, the projections of the widening portion 21 and the auxiliary structure 400 in the top view direction are at least partially staggered along the length extension direction of the electrode finger 20, so as to adjust the acoustic impedance of the edge area A12, so that the acoustic impedance of the area with the widening portion 21 is different from the acoustic impedance of the area with the auxiliary structure 400, so that the surface acoustic wave device 1000 can better suppress both high-order transverse modes and low-order transverse modes, so as to effectively suppress the transverse modes of the surface acoustic wave device 1000, minimize the adverse effects of the transverse modes on the surface acoustic wave device 1000, and effectively prevent energy leakage. In addition, the surface acoustic wave device 1000 of the embodiment of the present application is not easily affected by the spacing distance of adjacent electrode fingers 20 along the second direction when the device is manufactured, and can be applied to a higher frequency band. In addition, this embodiment can also reduce the occurrence of quality problems such as the distance between adjacent electrode fingers 20 being too small and difficult to process or being easy to process short circuits, and compared with two additional structures 400 of different thicknesses, it can reduce the process steps and reduce costs. In addition, the solution of realizing the acoustic impedance difference of the corresponding two regions by using two additional structures 40 of different thicknesses requires multiple processing of the additional structures 400 of different thicknesses; compared with the solution of realizing the acoustic impedance difference of the corresponding two regions by using two additional structures 40 of different thicknesses, the surface acoustic wave device 1000 of this embodiment can reduce the processing technology and reduce the process cost.

[0136] In addition, since the auxiliary structure 400 is a non-conductive structure, a dielectric layer 500 is provided between the auxiliary structure 400 and the interdigital transducer 200 in the top view direction, so the surface acoustic wave device 1000 is easy, convenient and simple to process. The surface acoustic wave device 1000 of the embodiment of the present application has a reasonable structural design, is easy to process, and has a good lateral mode suppression effect.

[0137] Exemplarily, one of the two edge regions A12 is provided with a widened portion 21 and an auxiliary structure 400. Exemplarily, both edge regions A12 are provided with a widened portion 21 and an auxiliary structure 400 at the same time.

[0138] Exemplarily, the piezoelectric substrate 100 includes the piezoelectric substrate 100 of any of the above embodiments. The IDT 200 includes the IDT 200 of any of the embodiments of the present application. The auxiliary structure 400 includes the auxiliary structure 400 of any of the above embodiments. The dielectric layer 500 includes the dielectric layer 500 of any of the above embodiments.

[0139] The embodiment of the present application also provides a surface acoustic wave device 1000, which includes a piezoelectric substrate 100, an IDT 200 and an auxiliary structure 300, wherein the IDT 200 is disposed on the piezoelectric substrate 100; in the arrangement direction of two bus bars 10 of the IDT 200, there is a crossover area A1 between the two bus bars 10, and the crossover area A1 includes a middle area A11 and edge areas A12 located at both ends of the middle area A11; wherein, in the arrangement direction of each electrode finger 20 of the IDT 200, the crossover area A1 It is the area where the electrode fingers 20 overlap with each other; the electrode finger 20 includes a widened portion 21 located in the edge area A12; the auxiliary structure 400 is located in the edge area A12, and the auxiliary structure 400 includes a first area, a second area and a third area. In the length extension direction of the electrode finger 20, the first area and the third area are respectively located on two opposite sides of the second area; wherein, in the same edge area A12, the auxiliary structure 400 covers the widened portion 21, and the projection of the second area in the top view direction overlaps with the widened portion 21 along the length extension direction of the electrode finger 20.

[0140] In the surface acoustic wave device 1000 of the above-mentioned embodiment, since in the same edge area A12, the auxiliary structure 400 covers the widened portion 21, and the projection of the second area in the top view direction overlaps with the widened portion 21 along the length extension direction of the electrode finger 20, it is possible to adjust the acoustic impedance of the edge area A12 so that the acoustic impedance of the area provided with the widened portion 21 is different from the acoustic impedance of the area provided with the auxiliary structure 400, so that the surface acoustic wave device 1000 can better suppress both high-order lateral modes and low-order lateral modes, thereby effectively suppressing the lateral modes of the surface acoustic wave device 1000, minimizing the adverse effects of the lateral modes on the surface acoustic wave device 1000 as much as possible, and effectively preventing energy leakage.

[0141] Exemplarily, the length of at least one of the first region and the third region in the length extension direction of the electrode finger 20 is smaller than the length of the second region in the length extension direction of the electrode finger 20. Exemplarily, the length of at least one of the first region and the third region in the length extension direction of the electrode finger 20 is smaller than 50% of the length of the second region in the length extension direction of the electrode finger 20.

[0142] Exemplarily, the relevant description of acoustic impedance refers to any suitable embodiment mentioned above, which will not be repeated here.

[0143] Exemplarily, the piezoelectric substrate 100 includes the piezoelectric substrate 100 of any one of the above embodiments. The IDT 200 includes the IDT 200 of any one of the above embodiments. The widened portion 21 includes the widened portion 21 of any one of the above embodiments. The auxiliary structure 400 includes the auxiliary structure 400 of any one of the above embodiments.

[0144] Exemplarily, the positional relationship of the auxiliary structure 400 may refer to the previous embodiment and will not be described in detail here.

[0145] The present application also provides a surface acoustic wave device 1000, including a piezoelectric substrate 100, an IDT 200 and an auxiliary structure 400, wherein the IDT 200 is disposed on the piezoelectric substrate 100; in the arrangement direction of the two bus bars 10 of the IDT 200, there is a crossover region A1 between the two bus bars 10, and the crossover region A1 includes a middle region A11 and edge regions A12 located at both ends of the middle region A11; wherein, in the arrangement direction of each electrode finger 20 of the IDT 200, the crossover region A11 is disposed between the two bus bars 10, and the crossover region A12 includes an intermediate region A11 and edge regions A12 located at both ends of the intermediate region A11; wherein, in the arrangement direction of each electrode finger 20 of the IDT 200, the crossover region A11 is disposed between the two bus bars 10, and ... Area A1 is the area where the electrode fingers 20 overlap with each other; the electrode finger 20 includes a widened portion 21 located in the edge area A12; the auxiliary structure 400 is located in the edge area A12; wherein the widened portion 21 includes a fourth area, a fifth area and a sixth area, and in the length extension direction of the electrode finger 20, the fourth area and the sixth area are respectively located on two opposite sides of the fifth area; in the same edge area A12, the projection of the auxiliary structure 400 in the top view direction overlaps with the fifth area along the length extension direction of the electrode finger 20.

[0146] In the surface acoustic wave device 1000 of the above-mentioned embodiment, since in the same edge area A12, the projection of the auxiliary structure 400 in the top-view direction overlaps with the fifth area along the length extension direction of the electrode finger 20, it is possible to adjust the acoustic impedance of the edge area A12 so that the acoustic impedance of the area provided with the widened portion 21 is different from the acoustic impedance of the area provided with the auxiliary structure 400, so that the surface acoustic wave device 1000 can better suppress both high-order lateral modes and low-order lateral modes, thereby effectively suppressing the lateral modes of the surface acoustic wave device 1000, minimizing the adverse effects of the lateral modes on the surface acoustic wave device 1000 as much as possible, and effectively preventing energy leakage.

[0147] Exemplarily, the length of at least one of the fourth region and the sixth region in the length extension direction of the electrode finger 20 is smaller than the length of the fifth region in the length extension direction of the electrode finger 20. Exemplarily, the length of at least one of the fourth region and the sixth region in the length extension direction of the electrode finger 20 is smaller than 50% of the length of the fifth region in the length extension direction of the electrode finger 20.

[0148] Exemplarily, the relevant description of acoustic impedance refers to any suitable embodiment mentioned above, which will not be repeated here.

[0149] Exemplarily, the piezoelectric substrate 100 includes the piezoelectric substrate 100 of any one of the above embodiments. The IDT 200 includes the IDT 200 of any one of the above embodiments. The widened portion 21 includes the widened portion 21 of any one of the above embodiments. The auxiliary structure 400 includes the auxiliary structure 400 of any one of the above embodiments.

[0150] Exemplarily, the positional relationship of the IDT 200 or the widened portion 21 may refer to the previous embodiments, which will not be described in detail herein.

[0151] An embodiment of the present application further provides a filter, comprising the surface acoustic wave device 1000 of any one of the above embodiments.

[0152] Exemplarily, the filter includes a plurality of surface acoustic wave devices 1000, wherein at least one surface acoustic wave device 1000 includes the surface acoustic wave device 1000 of any of the above embodiments. The structures of the surface acoustic wave devices 1000 may be the same or different, which is not limited here.

[0153] An embodiment of the present application also provides a radio frequency front-end module, comprising the surface acoustic wave device 1000 of any one of the above embodiments.

[0154] In some embodiments, the RF front-end module can be applied to electronic devices, which may include but are not limited to LED panels, tablet computers, notebooks, computers, navigators, mobile phones, electronic watches and other electronic devices or components with PCBs, and this application does not impose any restrictions on this.

[0155] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "mechanically coupled" and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium. It can be the internal connection of two elements or the interaction relationship between two elements. The mechanical coupling or coupling of two components includes direct coupling and indirect coupling, for example, direct fixed connection, connection through a transmission mechanism, etc. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0156] The disclosure above provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described above. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the various specific processes and material examples provided by the present application, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0157] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific method steps, features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific method steps, features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0158] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A surface acoustic wave device, characterized in that: The surface acoustic wave device includes: a piezoelectric substrate; an interdigital transducer disposed on the piezoelectric substrate; in the arrangement direction of two bus bars of the interdigital transducer, there is an intersection area between the two bus bars, and the intersection area includes an intermediate area and edge areas located at both ends of the intermediate area; wherein, in the arrangement direction of each electrode finger of the interdigital transducer, the intersection area is an area where the electrode fingers overlap each other; the electrode finger includes a widened portion located in the edge area; an auxiliary structure located in the edge area; wherein, within the same edge area, the projections of the widened portion and the auxiliary structure in the top view direction are at least partially staggered along the length extension direction of the electrode finger, and the acoustic impedance of the area provided with the widened portion is different from the acoustic impedance of the area provided with the auxiliary structure.

2. The surface acoustic wave device according to claim 1, characterized in that: Within the intersection area, the average value of the acoustic impedance of the area provided with the widened portion and the acoustic impedance of the area provided with the auxiliary structure is E; and E is less than the acoustic impedance of the intermediate area.

3. The surface acoustic wave device according to claim 1, characterized in that: The surface acoustic wave device has at least one of the following characteristics: Within the same edge area, the acoustic impedance of the area provided with the widened portion is less than the acoustic impedance of the area without the auxiliary structure and the widened portion; Within the same edge area, the acoustic impedance of the area provided with the auxiliary structure is less than the acoustic impedance of the area without the auxiliary structure and the widened portion; The acoustic impedance of the area provided with the auxiliary structure is less than the acoustic impedance of the area provided with the widened portion.

4. The surface acoustic wave device according to claim 1, characterized in that: The acoustic impedance of the one of the widened portion and the auxiliary structure that is closer to the intermediate area is greater than the acoustic impedance of the other that is farther from the intermediate area.

5. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: The length of the auxiliary structure in the arrangement direction of the two bus bars is L1, and 0.01λ < L1 < 2.6λ, where λ is the period of the electrode finger.

6. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: The thickness of the auxiliary structure is H1, and 0.002λ < H1 < 2λ, where λ is the period of the electrode finger.

7. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: The length of the widened portion in the arrangement direction of the two bus bars is L2, and 0 < L2 < 2.8λ, where λ is the period of the electrode finger.

8. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: The thickness of the widened portion is equal to the thickness of the electrode finger located in the intermediate area.

9. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: The width of the auxiliary structure in the arrangement direction of each electrode finger is W1, and the width of the electrode finger in the arrangement direction of each electrode finger is W3, and W1 ≥ W3 / 2.

10. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: Within the same edge area, the width of the widened portion in the arrangement direction of each electrode finger is W2, the width of the electrode finger in the arrangement direction of each electrode finger is W3, and the center distance between two adjacent electrode fingers is P3, and W3 ≤ W2 < (2P3 - W3).

11. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: The auxiliary structure is disposed on the side of the interdigital transducer facing the piezoelectric substrate; or, the auxiliary structure is disposed on the side of the interdigital transducer facing away from the piezoelectric substrate.

12. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: Within the same edge area, the projections of the widened portion and the auxiliary structure corresponding to the same electrode finger in the top view direction are adjacent along the length extension direction of the electrode finger; Or, In the same edge region, projections of the widened portion and the auxiliary structure corresponding to the same electrode finger in a plan view are arranged at intervals along the length extension direction of the electrode finger; or, In the same edge region, projections of the widened portion and the auxiliary structure corresponding to the same electrode finger in a plan view partially overlap along the length extension direction of the electrode finger.

13. The surface acoustic wave device according to claim 12, characterized in that: In the same edge region, the projections of the widened portion and the auxiliary structure corresponding to the same electrode finger in the top view are spaced apart by a preset distance L3 along the length extension direction of the electrode finger, L3<2.6λ, λ being the period of the electrode finger; or, In the same edge area, the projections of the widened portion and the auxiliary structure corresponding to the same electrode finger in the top view overlap by a preset distance L4 along the length extension direction of the electrode finger, L4<2.6λ, λ being the period of the electrode finger.

14. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: In the same edge region, the widened portion is further away from the middle region than at least part of the auxiliary structure; or, In the same edge region, the widened portion is closer to the middle region than at least part of the appendage structure.

15. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: The auxiliary structure is arranged on a side of the electrode finger facing the piezoelectric substrate; or, The auxiliary structure is arranged on a side of the electrode finger and / or the widened portion facing away from the piezoelectric substrate.

16. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: In the top-view direction, the auxiliary structure is spaced apart from or closely attached to the electrode finger.

17. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: The subsidiary structure includes a plurality of subsidiary blocks, and the subsidiary blocks are sequentially arranged at intervals in the arrangement direction of the electrode fingers; a projection of each electrode finger and one subsidiary block in a top-view direction at least partially overlaps.

18. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: The auxiliary structure overlaps with the projection of each electrode finger in the plan view direction in the arrangement direction of each electrode finger, and overlaps with the projection of a gap between any two adjacent electrode fingers in the plan view direction.

19. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: The auxiliary structure is a conductive structure or a non-conductive structure.

20. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: The surface acoustic wave device further comprises: A dielectric layer covers the interdigital transducer and is disposed on a side of the electrode finger away from the piezoelectric substrate.

21. The surface acoustic wave device according to claim 20, characterized in that: The dielectric layer is a temperature compensation layer.

22. The surface acoustic wave device according to claim 20, characterized in that: The auxiliary structure is arranged on a side of the dielectric layer away from the electrode finger; or, The dielectric layer is arranged on a side of the auxiliary structure away from the electrode fingers.

23. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: The piezoelectric substrate comprises a stacked piezoelectric film and a substrate, and the interdigital transducer is arranged on a surface of the piezoelectric film away from the substrate.

24. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: The interdigital transducer also includes: One end of the dummy finger is connected to one of the bus bars, and the other end is spaced apart from the end of the electrode finger connected to the other bus bar.

25. A surface acoustic wave device, characterized in that: The surface acoustic wave device comprises: Piezoelectric substrate; An interdigital transducer is provided on the piezoelectric substrate; in the arrangement direction of the two bus bars of the interdigital transducer, there is a crossover area between the two bus bars, and the crossover area includes a middle area and edge areas located at both ends of the middle area; wherein, in the arrangement direction of the electrode fingers of the interdigital transducer, the crossover area is an area where the electrode fingers overlap each other; and the electrode fingers include a widened portion located at the edge area; an auxiliary structure, at least one of the two edge regions being provided with the widened portion and the auxiliary structure; Wherein, within the same edge region, the projections of the widened portion and the auxiliary structure in the plan view are at least partially staggered along the length extension direction of the electrode finger; The subsidiary structure is a conductive structure, and includes a plurality of subsidiary blocks. In the arrangement direction of the electrode fingers, the subsidiary blocks are sequentially arranged at intervals; in the top view direction, each electrode finger is arranged in contact with one subsidiary block; A dielectric layer is disposed on the piezoelectric substrate and covers the interdigital transducer and the auxiliary structure.

26. A surface acoustic wave device, characterized in that: The surface acoustic wave device comprises: Piezoelectric substrate; An interdigital transducer is provided on the piezoelectric substrate; in the arrangement direction of the two bus bars of the interdigital transducer, there is a crossover area between the two bus bars, and the crossover area includes a middle area and edge areas located at both ends of the middle area; wherein, in the arrangement direction of the electrode fingers of the interdigital transducer, the crossover area is an area where the electrode fingers overlap each other; and the electrode fingers include a widened portion located at the edge area; an auxiliary structure, at least one of the two edge regions being provided with the widened portion and the auxiliary structure; Among them, in the same edge area, the projections of the widened portion and the auxiliary structure in the top-view direction are at least partially staggered along the length extension direction of the electrode finger; the auxiliary structure is a non-conductive structure; and in the top-view direction, a dielectric layer is provided between the auxiliary structure and the interdigital transducer.

27. A surface acoustic wave device, characterized in that: The surface acoustic wave device comprises: Piezoelectric substrate; An interdigital transducer is provided on the piezoelectric substrate; in the arrangement direction of the two bus bars of the interdigital transducer, there is a crossover area between the two bus bars, and the crossover area includes a middle area and edge areas located at both ends of the middle area; wherein, in the arrangement direction of the electrode fingers of the interdigital transducer, the crossover area is an area where the electrode fingers overlap each other; and the electrode fingers include a widened portion located at the edge area; An auxiliary structure is located in the edge region, the auxiliary structure includes a first region, a second region and a third region, and in the length extension direction of the electrode finger, the first region and the third region are respectively located on two sides away from the second region; Wherein, within the same edge region, the auxiliary structure covers the widened portion, and a projection of the second region in a plan view overlaps with the widened portion along a length extension direction of the electrode finger.

28. A surface acoustic wave device, characterized in that: The surface acoustic wave device comprises: Piezoelectric substrate; An interdigital transducer is provided on the piezoelectric substrate; in the arrangement direction of the two bus bars of the interdigital transducer, there is a crossover area between the two bus bars, and the crossover area includes a middle area and edge areas located at both ends of the middle area; wherein, in the arrangement direction of the electrode fingers of the interdigital transducer, the crossover area is an area where the electrode fingers overlap each other; and the electrode fingers include a widened portion located at the edge area; an accessory structure located in said marginal zone; The widened portion includes a fourth region, a fifth region and a sixth region, and in the length extension direction of the electrode finger, the fourth region and the sixth region are respectively located on two opposite sides of the fifth region; In the same edge region, a projection of the auxiliary structure in a plan view overlaps with the fifth region along a length extension direction of the electrode finger.

29. A filter, characterized in that: Comprising the surface acoustic wave device as described in any one of claims 1-28.

30. A radio frequency front-end module, characterized in that: Comprising the surface acoustic wave device as described in any one of claims 1-28.

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