CN116979927A

CN116979927A - Filter and electronic device

Info

Publication number: CN116979927A
Application number: CN202310888996.3A
Authority: CN
Inventors: 李阳; 刘旻俊; 杜波; 王华磊; 倪建兴
Original assignee: Ruishi Chuangxin Chongqing Technology Co ltd
Current assignee: Ruishi Chuangxin Chongqing Technology Co ltd
Priority date: 2023-07-19
Filing date: 2023-07-19
Publication date: 2023-10-31

Abstract

The embodiment of the application provides a filter and electronic equipment, the filter comprises: a first resonator and a second resonator. The first resonator comprises a first interdigital transducer and first reflecting grids arranged on two sides of the first interdigital transducer. The second resonator includes a second interdigital transducer and second reflective gratings disposed on both sides of the second interdigital transducer. The first resonator and the second resonator share a piezoelectric substrate, and a scattering structure is disposed in the piezoelectric substrate. By arranging the first resonator and the second resonator on the same piezoelectric substrate and arranging the scattering structure in the piezoelectric substrate, the scattering structure is used for carrying out diffuse reflection on the sound wave leaked from the first reflecting grating in the first resonator and/or carrying out diffuse reflection on the sound wave leaked from the second reflecting grating in the second resonator, so that the mutual influence of the first resonator and the second resonator is reduced, and the performance of the filter is improved.

Description

Filter and electronic device

Technical Field

The embodiment of the application relates to the technical field of radio frequency filtering, in particular to a filter and electronic equipment.

Background

With the continuous development of science and technology, new generation information technology plays an increasingly important role in various industries. Among them, the technical support of the filter is critical for the radio frequency field.

The filter is mostly composed of a plurality of resonators, the resonators generally comprise a piezoelectric substrate, a metal electrode above the piezoelectric substrate, the metal electrode generally comprises an interdigital transducer and reflecting grating structures positioned at two sides of the interdigital transducer, the interdigital transducer excites the surface acoustic wave, and the reflecting grating constrains the surface acoustic wave within the interdigital transducer.

However, in the filter, in order to maintain the compactness of the structure, there is generally a case where two resonators overlap in the propagation direction of the acoustic wave, and at this time, the acoustic wave leaked from the reflection gate of the resonator interferes with the other resonator overlapping with the resonator, and eventually deteriorates the performance of the filter.

Disclosure of Invention

In view of the foregoing, it is desirable to provide a filter and an electronic device that at least partially improve the foregoing.

In a first aspect, an embodiment of the present application provides a filter, including: a first resonator and a second resonator. The first resonator comprises a first interdigital transducer and first reflecting grids arranged on two sides of the first interdigital transducer. The second resonator comprises a second interdigital transducer and second reflecting grids arranged at two sides of the second interdigital transducer, the second resonator is adjacent to the first resonator, and the second resonator has an overlapping area with the first resonator in the acoustic wave propagation direction of the first resonator; wherein the first resonator and the second resonator share a piezoelectric substrate, and a scattering structure is arranged in the piezoelectric substrate and used for carrying out diffuse reflection on the sound wave leaked from the first reflecting grating and/or carrying out diffuse reflection on the sound wave leaked from the second reflecting grating.

In one embodiment, a scattering structure comprises: and a first portion at least partially located between the first resonator and the second resonator, the projection of the first portion in the direction of propagation of the acoustic wave at least partially overlapping the projection of the overlap region in the direction of propagation of the acoustic wave.

In one embodiment, the projection of the first portion in the direction of propagation of the sound wave covers at least the projection of the overlap region in the direction of propagation of the sound wave.

In one embodiment, the first portion is a groove or an embedded structure.

In one embodiment, the side wall of the first portion adjacent to the first reflective grating and/or the second reflective grating is provided with a matte surface.

In one embodiment, the longitudinal cross-section of the first portion is rectangular or trapezoidal or tapered or scalloped or oval or arcuate.

In one embodiment, the angle between the plane of the sidewall of the first portion and the plane of the piezoelectric substrate is between 27 ° and 165 °.

In one embodiment, at least one sidewall of the first portion is perpendicular to the plane of the piezoelectric substrate and the sidewall perpendicular to the plane of the piezoelectric substrate is roughened.

In one embodiment, the piezoelectric substrate includes a first surface facing away from the first interdigital transducer and the second interdigital transducer, the first surface being roughened, the scattering structure further comprising: a second portion comprising the first surface.

In one embodiment, a piezoelectric substrate includes: the piezoelectric layer covers the substrate, a first interdigital transducer and a second interdigital transducer are arranged on the upper surface, which is away from the substrate, of the piezoelectric layer, and the first part is positioned on the piezoelectric layer or the first part is positioned on the piezoelectric layer and extends from the piezoelectric layer to the substrate.

In one embodiment, the piezoelectric substrate further includes an intermediate layer disposed on an upper surface of the substrate facing away from the first surface, and the intermediate layer is covered by the piezoelectric layer, the first portion being located on the piezoelectric layer, or the first portion being located on the piezoelectric layer and extending from the piezoelectric layer to the intermediate layer, or the first portion being located on the piezoelectric layer and extending from the piezoelectric layer to the substrate.

In one embodiment, a piezoelectric substrate includes: the piezoelectric layer covers the substrate, a first interdigital transducer and a second interdigital transducer are arranged on the upper surface of the piezoelectric layer, which is away from the substrate, and the depth of the first part is at least greater than the thickness of the piezoelectric layer.

In one embodiment, the first portion has at least one recess and/or at least one projection in a direction orthogonal to the direction of propagation of the sound wave.

In one embodiment, the depth of the first portion is greater than 0.5 times the spatial period of the first interdigital transducer or 0.5 times the spatial period of the second interdigital transducer.

In one embodiment, the first portion extends through the piezoelectric substrate.

In one embodiment, the width of the first portion in the direction of propagation of the acoustic wave is greater than or equal to 100nm.

In one embodiment, the distance between the scattering structure and the first reflective grating is greater than or equal to 100nm and/or the distance between the second resonator is greater than or equal to 100nm.

In one embodiment, the first interdigital transducer comprises a first intersection region and the second interdigital transducer comprises a second intersection region, the first intersection region and the second intersection region having an intersection overlap region in the direction of propagation of the acoustic wave, and the projection of the first portion in the direction of propagation of the acoustic wave at least partially overlaps the projection of the intersection overlap region in the direction of propagation of the acoustic wave.

In one embodiment, the projection of the first portion in the direction of propagation of the sound wave covers at least the projection of the cross overlap area in the direction of propagation of the sound wave.

In a second aspect, an embodiment of the present application provides a filter, including: a first resonator and a second resonator. The first resonator comprises a first interdigital transducer and first reflecting grids arranged on two sides of the first interdigital transducer. The second resonator comprises a second interdigital transducer and second reflecting grids arranged at two sides of the second interdigital transducer, the second resonator is adjacent to the first resonator, and the second resonator has an overlapping area with the first resonator in the acoustic wave propagation direction of the first resonator; wherein, the first resonator and the second resonator share a piezoelectric substrate, a scattering structure is arranged in the piezoelectric substrate, and the scattering structure is provided with a rough surface; the sound wave leaked from the first reflecting grating adjacent to the scattering structure and/or the second reflecting grating adjacent to the scattering structure passes through the scattering structure and is diffusely reflected at the side wall of the scattering structure provided with the rough surface.

In a third aspect, an embodiment of the present application provides a filter, including: a first resonator, a second resonator, and a scattering structure. The first resonator comprises a first interdigital transducer and first reflecting grids arranged on two sides of the first interdigital transducer. The second resonator comprises a second interdigital transducer and second reflecting grids arranged at two sides of the second interdigital transducer, the second resonator is adjacent to the first resonator, and the second resonator has an overlapping area with the first resonator in the acoustic wave propagation direction of the first resonator; the piezoelectric substrate at least comprises a piezoelectric layer and a substrate, the piezoelectric layer covers the substrate, and a first interdigital transducer and a second interdigital transducer are arranged on the upper surface of the piezoelectric layer, which is away from the substrate. The scattering structure is located within the piezoelectric layer, or the scattering structure is located within the piezoelectric layer and within the substrate, the scattering structure being for diffusely reflecting sound waves leaking from the first reflection grating and/or for diffusely reflecting sound waves leaking from the second reflection grating.

In a fourth aspect, an embodiment of the present application further provides an electronic device, including any one of the filters described above.

According to the filter and the electronic device provided by the embodiment of the application, the first resonator and the second resonator are arranged on the same piezoelectric substrate, and the scattering structure is arranged in the piezoelectric substrate, so that the scattering structure is used for carrying out diffuse reflection on the sound wave leaked from the first reflecting grating in the first resonator and/or carrying out diffuse reflection on the sound wave leaked from the second reflecting grating in the second resonator, the mutual influence of the sound waves between the first resonator and the second resonator is reduced, and the performance of the filter is improved.

Drawings

Fig. 1 is a schematic cross-sectional view showing a part of a structure of a filter according to an embodiment of the present application.

Fig. 2 is a top view showing a part of the structure of a filter according to an embodiment of the present application.

Fig. 3 is a schematic diagram showing an arrangement of a first resonator and a second resonator according to another embodiment of the present application.

Fig. 4 is a top view showing a part of the structure of a second filter according to an embodiment of the present application.

Fig. 5 is a top view showing a part of the structure of a third filter according to an embodiment of the present application.

Fig. 6 is a schematic cross-sectional view showing a part of the structure of a fourth filter according to an embodiment of the present application.

Fig. 7 is a schematic cross-sectional view showing a part of the structure of a fifth filter according to an embodiment of the present application.

Fig. 8 is a schematic cross-sectional view showing a part of the structure of a sixth filter according to an embodiment of the present application.

Fig. 9 shows a schematic structural diagram of a resonator R1 of the first comparative example.

Fig. 10 shows a mechanical energy storage profile of the non-waveguide mode of the resonator R1 of the first comparative example.

Fig. 11 shows a mechanical energy storage distribution diagram of the non-waveguide mode of the resonator R1 of the first comparative example in the acoustic propagation direction.

Fig. 12 shows a mechanical energy storage distribution graph of the waveguide mode of the resonator R1 of the first comparative example.

Fig. 13 shows a graph of the mechanical energy storage distribution of the waveguide mode of the resonator R1 of the first comparative example in the acoustic propagation direction.

Fig. 14 shows a graph of harmonic admittance of the resonator R1 in the first comparative example.

Fig. 15 shows a schematic structural view provided by the second comparative example.

Fig. 16 shows a mie stress distribution diagram of the waveguide mode of the first resonator in the second comparative example.

Fig. 17 shows a graph of harmonic admittances of the first resonator in the second comparative example.

Fig. 18 shows a schematic structural view of a third comparative example.

Fig. 19 shows a mie stress distribution diagram of a waveguide mode of the first resonator in the third comparative example.

Fig. 20 shows a graph of harmonic admittances of the first resonator in the third comparative example.

Fig. 21 shows a mie stress distribution diagram of a waveguide mode of the first resonator in the first embodiment.

Fig. 22 shows a graph of the harmonic admittance of the first resonator in the first embodiment.

Fig. 23 shows forward voltage gain graphs of the second comparative example, the third comparative example, and the first example.

Reference numerals: 10-filter, 110-first resonator, 111-first interdigital transducer, 1111-first bus bar, 1112-second bus bar, 1113-first finger, 1114-second finger, 112-first reflective grating, 120-second resonator, 121-second interdigital transducer, 122-second reflective grating, 130-piezoelectric substrate, 1311-first portion, 1311 a-concave portion, 1311 b-convex portion, 1312-second portion, 133-piezoelectric layer, 134-substrate, 135-intermediate layer.

Detailed Description

In order to make the present invention better understood by those skilled in the art, the following description of the present invention will be made in detail with reference to the accompanying drawings in the embodiments of the present invention. It will be apparent that the described embodiments are only some, but not all, of the embodiments of the invention. All other embodiments, based on the embodiments of the invention, which a person skilled in the art would obtain without making any inventive effort, are within the scope of the invention.

In view of the above, a first embodiment of the present application provides a filter 10, referring to fig. 1, the filter 10 may include: the first resonator 110 and the second resonator 120. (note that in the drawings of the present application, x may be represented as a sound wave propagation direction of the first resonator 110, y is a direction in a plane of the sound wave propagation direction of the first resonator 110 or the second resonator 120 and orthogonal to x, z is a depth direction, and z is perpendicular to the x direction and perpendicular to the y direction), it should be understood that in some other embodiments, the filter 10 may further include a third resonator, a fourth resonator, etc., that is, the filter 10 may include a plurality of resonators, and may further include other devices, such as a capacitor, an inductor, etc., where each resonator and other period may be connected by a wire; the present application is described with respect to a filter including a first resonator 110 and a second resonator 120, and the first resonator 110 and the second resonator 120 are merely exemplary two adjacent resonators in the filter 10, and not specific to any two resonators in the filter 10.

Referring to fig. 1 and 2 together, the first resonator 110 may include a first interdigital transducer 111 and first reflective gratings 112 disposed on two sides of the first interdigital transducer 111. It should be noted that, in fig. 1 and 2, only the first reflective grating 112 located on the right side of the first interdigital transducer 111 and the second reflective grating 122 located on the left side of the second interdigital transducer 121 are shown, and those skilled in the art should understand that both the left and right sides of the first interdigital transducer 111 and the second interdigital transducer 122 should be provided with reflective gratings, which are not shown in the drawings.

Note that the solid line in the thickness direction of the piezoelectric substrate 130 in fig. 1 is merely for dividing the region in the thickness direction, and is not essential, and in an actual filter structure, the solid line is not present.

Specifically, the first interdigital transducer 111, the first reflective grating 112, the second interdigital transducer 121, and the second reflective grating 122 may be formed in the topological form of metal electrodes, and the material structure of the metal electrodes may be elemental metals such as aluminum (Al), copper (Cu), silver (Ag), or the like, or may be an alloy or a multilayer film structure composed of a plurality of elemental metals, which is not particularly limited herein.

With continued reference to fig. 2, in this embodiment, the structure of the first interdigital transducer 111 may be consistent with the structural parameters of the second interdigital transducer 121, where the structural parameters include materials, duty cycle, finger count, etc., without specific limitation; of course, the structure of the first interdigital transducer 111 may be inconsistent with the structure of the second interdigital transducer 121, such as different numbers of fingers of the first interdigital transducer 111 and the second interdigital transducer 121, different materials of the first interdigital transducer 111 and the second interdigital transducer 121, and the like, and the specific limitation is not imposed herein.

The structural parameters of the first interdigital transducer 111 in the embodiment of the present application may be consistent with the structure of the second interdigital transducer 121, and the structural parameters of the first interdigital transducer 111 may be inconsistent with the structural parameters of the second interdigital transducer 121, and the structure of the first resonator 110 will be described in detail as an example. The first interdigital transducer 111 may include a first bus bar 1111, and a number of first and second bus bars 1113 and 1112 connected with the first bus bar 1111, and a number of second bus bars 1114 connected with the second bus bar 1112.

For example, in the present embodiment, the first finger 1113 in fig. 2 may be provided in 3, and the 3 first finger 1113 may be uniformly or non-uniformly provided on the first bus bar 1111, and the first bus bar 1111 and the second bus bar 1112 are disposed opposite to each other. One end of the first finger 1113 is connected to the first bus bar 1111, the other end extends in the direction of the second bus bar 1112, and a gap exists between the first finger 1113 and the second bus bar 1112. One end of the second finger 1114 is connected to the second bus bar 1112, the other end extends in the direction of the first bus bar 1111, and a gap exists between the second finger 1114 and the first bus bar 1111.

In this embodiment, the first finger 1113 and the second finger 1114 may be arranged in a cross manner, that is, one second finger 1114 may be disposed between two adjacent first finger 1113, and one first finger 1113 may be disposed between two adjacent second finger 1114. This may result in a more uniform excitation of the acoustic waves by the first interdigital transducer 111 when in operation.

It should be noted that, the embodiments of the present application do not limit the specific number of the first finger 1113 and the second finger 1114, for example, the number of the first finger 1113 may be 30, 61, 90, etc., and the number of the second finger 1114 may be identical or inconsistent with the number of the first finger 1113.

The second resonator 120 may include a second interdigital transducer 121 and second reflective gratings 122 disposed on both sides of the second interdigital transducer 121. It should be noted that, in fig. 1 and 2, only the first reflection grating 112 located on the right side of the first interdigital transducer 111 and the second reflection grating 122 located on the left side of the second interdigital transducer 121 are shown, and those skilled in the art should understand that both sides of the first interdigital transducer 111 and the second interdigital transducer 122 in the respective acoustic wave propagation directions should be provided with reflection gratings, which are not shown in the drawings.

In the present embodiment, the second resonator 120 may be adjacent to the first resonator 110, and the second resonator 120 has an overlapping region with the first resonator 110 in the acoustic wave propagation direction of the first resonator 110, which may be understood as a region where the projections of the first resonator 110 and the second resonator 120 each in the acoustic wave propagation direction of the first resonator 110 overlap.

Specifically, referring to fig. 2, in an embodiment, the first resonator 110 and the second resonator 120 may be arranged in parallel and side by side, that is, the acoustic wave propagation directions of the first resonator 110 and the second resonator 120 are the same, for example, the acoustic wave propagation directions of the first resonator 110 and the second resonator 120 are all the x direction, and the acoustic wave propagation directions of the first resonator 110 and the second resonator 120 are coincident. The range of the overlapping area is the same as the range of the projection area of the first resonator 110 in the acoustic propagation direction of the first resonator 110 at this time, or the range of the overlapping area is the same as the range of the projection area of the second resonator 120 in the acoustic propagation direction of the first resonator 110.

Referring to fig. 3, in another embodiment, the acoustic wave propagation directions of the first resonator 110 and the second resonator 120 may also be different, where there is a cross between the acoustic wave propagation directions of the first resonator 110 and the second resonator 120, for example, the acoustic wave propagation direction of the first resonator 110 is defined as the x direction, the acoustic wave propagation direction of the second resonator 120 is crossed with the x direction, specifically, the acoustic wave propagation direction of the second resonator 120 is orthogonal with the x direction, that is, the acoustic wave propagation direction of the second resonator 120 is the y direction, that is, the acoustic wave propagation directions of the first resonator 110 and the second resonator 120 are perpendicular. The overlapping region is a region where the projection of the first resonator 110 in the x-direction overlaps the projection of the second resonator 120 in the x-direction.

It should be noted that fig. 3 only shows a case where the acoustic propagation direction of the first resonator 110 is perpendicular to the acoustic propagation direction of the second resonator 120, and in some other embodiments, the included angle between the acoustic propagation directions of the first resonator 110 and the second resonator 120 may be any other value, for example, 30 °, 45 °, 60 °, etc., which is not limited herein.

Referring to fig. 1 again, the first resonator 110 and the second resonator 120 share a piezoelectric substrate 130, and the piezoelectric substrate 130 may be a single layer or multiple layers, and the piezoelectric substrate 130 may include at least a piezoelectric layer, and the piezoelectric layer may be a silicon (Si) substrate, lithium tantalate (LiTaO) ₃ ) Substrate, lithium niobate (LiNbO) ₃ ) A substrate, etc. A scattering structure is provided within the piezoelectric substrate 130 for diffusely reflecting the acoustic wave leaking from the first reflecting grating 112 and/or for diffusely reflecting the acoustic wave leaking from the second reflecting grating 122.

In an embodiment, the scattering structure may comprise: a first portion 1311 located at least partially between the first resonator 110 and the second resonator 120, the projection of the first portion 1311 in the direction of propagation of the acoustic wave (x-direction) at least partially overlapping the projection of the overlap region in the direction of propagation of the acoustic wave.

In this embodiment, the first portion 1311 is located in the piezoelectric substrate 130 and between the first resonator 110 and the second resonator 120, and the first portion 1311 may be an opening or an embedded structure. The above-described partial overlap may refer to the overlap of the projection of the first portion 1311 and the overlap region in the length direction. That is, the projection of the first portion 1311 in the acoustic wave propagation direction (x-direction) at least partially overlaps the projection of the overlap region in the acoustic wave propagation direction.

Specifically, the first portion 1311 may completely overlap the overlap region in the longitudinal direction (of course, only the length direction is referred to as the length of the overlap region in the longitudinal direction, and the length of the projection of the first portion 1311 in the longitudinal direction is not necessarily equal to the length of the overlap region in the longitudinal direction).

Or the first portion 1311 may partially overlap the overlapping area in the length direction, where the length of the projection of the first portion 1311 in the length direction is greater than or equal to or less than the length of the overlapping area in the length direction, i.e., the projection of the first portion may be entirely within the overlapping area or partially beyond the overlapping area.

Specifically, for example, referring to fig. 2, the extending direction of the first portion 1311 in fig. 2 is perpendicular to the acoustic propagation direction of the first resonator 110, i.e. if the acoustic propagation direction of the first resonator 110 is the x-direction, the length direction of the first portion 1311 is the y-direction. The length direction of the first interdigital transducer 111 of the first resonator 110 is defined herein to be perpendicular to the acoustic propagation direction of the first resonator 110, that is, the length direction of the first interdigital transducer 111 or the first reflective grating 112 finger, and in the following embodiments, unless specifically limited, the length direction is the length direction of the first interdigital transducer 111 or the first reflective grating 112 finger.

The extending direction in this embodiment refers to a straight line direction in which the two ends of the first portion 1311 are connected in a top view, that is, in a top view, the extending direction of the first portion 1311 to the two ends is the extending direction of the first portion 1311, and it should be noted that the extending direction proposed in this embodiment does not refer to a direction in which the first portion 1311 extends in the thickness direction of the piezoelectric substrate; and in fig. 2, the direction of extension is the same as the length direction, although in some embodiments the direction of extension is different from the length direction, as shown in fig. 4.

At this time, the length of the projection of the first portion 1311 in the x direction in the length direction is the length of the first portion 1311, and the length is the same as the length of the overlap region in the length direction (since the overlap region is an overlap region between the projection of the first resonator 110 in the acoustic propagation direction of the first resonator 110 and the projection of the second resonator 120 in the acoustic propagation direction of the first resonator 110, the overlap region here corresponds to the projection of the overlap region in the acoustic propagation direction of the first resonator 110), that is, the range of the projection of the first portion 1311 in the x direction in the length direction and the range of the overlap region in the length direction overlap completely (as above, it does not mean that the range of the projection of the first portion 1311 in the x direction in the thickness direction of the piezoelectric substrate and the range of the overlap region in the thickness direction of the piezoelectric substrate overlap completely overlap).

For example, referring to fig. 4, in fig. 4, an angle exists between the extending direction of the first portion 1311 and the acoustic propagation direction of the first resonator 110, that is, if the acoustic propagation direction of the first resonator 110 is the x direction, the length direction of the first portion 1311 is any one direction between the x direction and the y direction, and the angle between the extending direction of the first portion 1311 and the x direction may be 30 °, 45 °, 60 °, etc., which is not limited herein.

At this time, the length of the projection of the first portion 1311 in the x direction is smaller than the length of the first portion 1311, and the projection length of the first portion 1311 in the x direction is smaller than the projection length of the overlap region in the x direction, that is, the range of the projection of the first portion 1311 in the x direction in the length direction partially coincides with the range of the overlap region in the length direction.

Further, the projection of the first portion 1311 in the direction of sound wave propagation covers at least the projection of the overlap region in the direction of sound wave propagation. For example, referring to fig. 2 or fig. 5, taking fig. 5 as an example, compared to the structure in fig. 4, the length of the first portion 1311 in fig. 5 projected in the length direction in the acoustic propagation direction of the first resonator 110 is longer than the length of the first portion 1311 in fig. 4 projected in the length direction in the acoustic propagation direction of the first resonator 110.

In this embodiment, the length of a structure projected in the length direction of the acoustic propagation direction of the first resonator 110 is defined as the projected length of the structure in the acoustic propagation direction of the first resonator 110, that is, the projected length of the structure in the x direction, in fig. 5, the projected length of the first portion 1311 in the x direction is the same as the projected length of the overlapping region, and the projected length of the first portion 1311 in the x direction coincides with the projected length of the overlapping region in the x direction, where the projected length coincidence can be regarded as a first overlapping range (defined herein as a first overlapping region, for distinguishing the previous overlapping region) where the projected length of the first portion 1311 in the x direction overlaps with the overlapping region is equal to the projected length of the overlapping region. This may allow first portion 1311 to substantially diffusely reflect both leaked sound waves, further reducing interaction between first resonator 110 and second resonator 120.

Of course, fig. 2 or 5 are merely exemplary and are extreme, and the projection of the first portion 1311 in the direction of propagation of the acoustic wave just covers the projection of the overlap region in the direction of propagation of the acoustic wave, in other embodiments the projection of the first portion 1311 in the direction of propagation of the acoustic wave covers the projection of the overlap region in the direction of propagation of the acoustic wave, and the projection length of the first portion 1311 in the direction of propagation of the acoustic wave is greater than the projection length of the overlap region, i.e., the length of the first overlap region in the length direction where the projection of the first portion 1311 in the direction of propagation of the acoustic wave overlaps the overlap region is greater than the projection length of the overlap region.

In this embodiment, the projection of the first portion 1311 in the acoustic wave propagation direction at least covers the projection of the overlapping area in the acoustic wave propagation direction, so that the acoustic wave leaked from the first reflecting grating 112 is diffusely reflected and/or the acoustic wave leaked from the second reflecting grating 122 can sufficiently enter the first portion 1311, so that, based on the first portion, diffuse reflection of the leaked acoustic wave can be achieved, the interaction of the first resonator 110 and the second resonator 120 is reduced, and the performance of the filter 10 is improved.

Referring to fig. 4, there is an intersection region between the first intersection region of the first interdigital transducer 111 and the second intersection region of the second interdigital transducer 121 in the acoustic wave propagation direction, and the projection of the first portion 1311 in the acoustic wave propagation direction at least partially overlaps with the projection of the intersection region in the acoustic wave propagation direction.

In this embodiment, the first intersection region of the first interdigital transducer 111 may be regarded as a region where the first finger 1113 and the second finger 1114 have an intersection overlap in the acoustic propagation direction of the first resonator 110, and likewise, the second intersection region of the second interdigital transducer 121 may be regarded as a region where the fingers respectively connected to the two bus bars of the second interdigital transducer 121 have an intersection overlap in the acoustic propagation direction of the second resonator 120.

It should be noted that the first intersection region in the present embodiment includes, in addition to the thickness of the first interdigital transducer 110, the thickness of the piezoelectric substrate 130 in the thickness direction of the piezoelectric substrate 130, that is, includes, from the first intersection region in the top view direction (the direction in which the first interdigital transducer points to the piezoelectric substrate), a region where there is an intersection overlap of the first finger 1113 and the second finger 1114 in the acoustic propagation direction of the first resonator 110 and a region directly facing the piezoelectric substrate 130 below the intersection overlap region, and the second intersection region is the same as the first intersection region, and includes, in addition to the thickness of the second interdigital transducer 120, the thickness of the piezoelectric substrate 130, that is, the projection thickness of the first interdigital transducer and the projection thickness of the substrate 133 in the thickness direction of the piezoelectric substrate 130 in the projection of the first intersection region in the acoustic propagation direction of the first resonator 110, and the projection thickness of the second intersection region and the projection thickness of the substrate 133 in the thickness direction of the second interdigital transducer in the thickness direction of the piezoelectric substrate 130.

The cross overlap region may be regarded as an overlap region between a projection of the first cross region in the acoustic propagation direction of the first resonator 110 and a projection of the second cross region in the acoustic propagation direction of the first resonator 110, and specifically reference may be made to a definition that the second resonator 120 has an overlap region with the first resonator 110 in the acoustic propagation direction of the first resonator 110.

In this embodiment, the acoustic waves of the resonators are mainly concentrated in the intersection region, so when the mutual interference of the acoustic waves between the two resonators is reduced, a first portion may be disposed in the intersection overlapping region of the two resonators, so that the intersection region reaches the first reflective grating 112 and the second reflective grating 122, and the acoustic waves leaked from the first reflective grating 112 and the second reflective grating 122 reach the first portion, so that the interference of the leaked acoustic waves on the intersection region of the two resonators is reduced.

In an embodiment, the distance between the first portion 1311 and the first reflective grating 112 and the distance between the first portion 1311 and the second reflective grating 122 are not limited, however, from a process perspective, the distance between the first portion 1311 and the first reflective grating 112 is too close, which may affect the formation of the first reflective grating 112, such as damage to the first reflective grating 112, resulting in the failure of the first reflective grating 112; likewise, too close a distance between the first portion 1311 and the second reflective grating 122 may affect the formation of the second reflective grating 122, whereby the distance between the first portion 1311 and the first reflective grating 112 and the distance between the first portion 1311 and the second reflective grating 122 may be defined in some embodiments.

It should be noted that, the distance between the first portion 1311 and the first reflective grating 112 in this embodiment means a distance between the first portion 1311 and the first reflective grating 112 adjacent to the first portion 1311, and the distance between the first portion 1311 and the second reflective grating 122 means a distance between the first portion 1311 and the second reflective grating 122 adjacent to the first portion 1311.

Specifically, a distance between the first portion 1311 and the first reflective grating 112 may be greater than or equal to 100nm (nanometers), and/or a distance between the first portion 1311 and the second resonator 120 may be greater than or equal to 100nm. Too small a distance between first portion 1311 and first reflective grating 112 and/or a distance between first portion 1311 and first reflective grating 112 may also affect the sound waves leaking from first reflective grating 112 and/or second reflective grating 122 to enter first portion 1311, thereby affecting the effect of diffuse reflection. Meanwhile, when the first portion 1311 is arranged, the first reflecting grating 112 and/or the second reflecting grating 122 are/is affected due to the limitation of the process, and even the first reflecting grating 112 and/or the second reflecting grating 122 are damaged, so that the stability and the reliability of the first resonator 110 and/or the second resonator 120 and the filter 10 are affected, in addition, the first portion 1311 is arranged far away from the first reflecting grating 112 and/or the second reflecting grating 122, the complexity of the process can be reduced, the process manufacturing is facilitated, and the manufacturing efficiency is improved.

For example, the distance between the first portion 1311 and the first reflective grating 112 may be 100nm, 150nm, 300nm, etc., and the distance between the first portion 1311 and the second reflective grating 122 may be 100nm, 150nm, 300nm, etc., without limitation.

With continued reference to fig. 2, in this embodiment, the width of the first portion 1311 in the acoustic wave propagation direction of the first resonator 110 is greater than or equal to 100nm. If the width of the first portion 1311 in the acoustic wave propagation direction is too small, the acoustic wave leaked from the first reflection grating 112 and/or the second reflection grating 122 may not sufficiently enter the first portion 1311, thereby affecting the subsequent diffuse reflection effect of the leaked acoustic wave. For example, the width of the first portion 1311 in the acoustic wave propagation direction may be set to 100nm, 150nm, 300nm, or the like, without limitation.

It will be appreciated that the width of the first portion 1311 in the direction of propagation of the acoustic wave may be selected based on the actual distance between the first resonator 110 and the second resonator 120, etc.

Specifically, referring to fig. 2, in an embodiment, the first resonator 110 and the second resonator 120 may be arranged in parallel and side by side, that is, the acoustic wave propagation directions of the first resonator 110 and the second resonator 120 are the same, for example, the acoustic wave propagation directions of the first resonator 110 and the second resonator 120 are all the x direction, and the cross overlap area is a projection overlap area of the first cross area and the second cross area in the x direction.

Referring to fig. 3, in another embodiment, the acoustic wave propagation directions of the first resonator 110 and the second resonator 120 may also be different, where there is a cross between the acoustic wave propagation directions of the first resonator 110 and the second resonator 120, for example, the acoustic wave propagation direction of the first resonator 110 is defined as the x direction, the acoustic wave propagation direction of the second resonator 120 is crossed with the x direction, specifically, the acoustic wave propagation direction of the second resonator 120 is orthogonal with the x direction, that is, the acoustic wave propagation direction of the second resonator 120 is the y direction, that is, the acoustic wave propagation directions of the first resonator 110 and the second resonator 120 are perpendicular. The crossover overlap area is the area of overlap of the projection of the first crossover region in the x-direction and the projection of the second crossover region in the x-direction.

It should be noted that fig. 3 only shows a case where the acoustic propagation directions of the first resonator 110 and the second resonator 120 are perpendicular to each other, and in some embodiments, the included angle between the acoustic propagation directions of the first resonator 110 and the second resonator 120 may be other values, for example, 30 °, 45 °, 60 °, and the like.

In this embodiment, the projection of the first portion 1311 in the direction of acoustic wave propagation at least partially overlaps the projection of the cross overlap region in the direction of acoustic wave propagation.

Specifically, the projection of the first portion 1311 in the acoustic wave propagation direction may overlap with the projection of the cross overlap region in the acoustic wave propagation direction entirely, or the projection of the first portion 1311 in the acoustic wave propagation direction may overlap with the projection of the cross overlap region in the acoustic wave propagation direction partially.

In this embodiment, with respect to the relation between the first portion 1311 and the cross overlap region, the projection of the first portion 1311 in the acoustic wave propagation direction and the projection of the cross overlap region in the acoustic wave propagation direction may be fully overlapped, which may be referred to as that the projection of the first portion 1311 in the acoustic wave propagation direction and the projection of the cross overlap region in the acoustic wave propagation direction fully overlap each other, the projection of the first portion 1311 in the acoustic wave propagation direction in the length direction fully covers the projection of the cross overlap region in the acoustic wave propagation direction, and the projection of the first portion 1311 in the acoustic wave propagation direction in the depth direction of the piezoelectric substrate 130 does not necessarily fully cover the projection of the cross overlap region in the acoustic wave propagation direction.

That is, the projection of the first portion 1311 in the direction of propagation of the acoustic wave and the projection of the cross overlap region in the direction of propagation of the acoustic wave can be considered to be entirely covered, expressed as: there is a second overlap range of overlap between the projection of the first portion 1311 in the acoustic wave propagation direction and the projection of the cross overlap region in the acoustic wave propagation direction, the projection length of the second overlap range in the length direction being equal to the projection length of the cross overlap region in the length direction, of course, the projection length of the first portion 1311 may be greater than or equal to the projection length of the second overlap range in the length direction.

Or the projection of the first portion 1311 in the acoustic wave propagation direction may overlap with the projection of the cross overlap region in the acoustic wave propagation direction, i.e. the projection of the first portion may be entirely within the overlap region or partially beyond the overlap region, as above, where the projection of the first portion 1311 may be entirely within the overlap region and also considered as having a projection length of the second overlap region in the length direction that is smaller than the projection length of the cross overlap region in the length direction; and the projection of the first portion 1311 exceeds the overlapping area, the projection length of the second overlapping area in the length direction is considered to be smaller than the projection length of the cross overlapping area in the length direction, and the projection length of the first portion 1311 may be larger than the projection length of the second overlapping area in the length direction.

Further, referring again to fig. 2 and 5, in some embodiments, the projection of the first portion 1311 in the direction of acoustic wave propagation covers at least the projection of the cross overlap region in the direction of acoustic wave propagation. This allows the acoustic wave that arrives at the reflective grating from the intersection of the resonators and leaks out to reach the first portion 1311, so that the leaking acoustic wave is diffusely reflected, reducing interference between the first intersection of the first resonator 110 and the second intersection of the second resonator 120.

In this embodiment, the projection of the first portion 1311 in the direction of propagation of the acoustic wave covers at least the projection of the cross overlap region in the direction of propagation of the acoustic wave.

Specifically, the projection of the first portion 1311 in the acoustic wave propagation direction and the projection of the cross overlap region in the acoustic wave propagation direction may at least overlap completely, and in the extreme case just overlap completely, the projection of the first portion 1311 in the acoustic wave propagation direction does not necessarily overlap completely the projection of the cross overlap region in the acoustic wave propagation direction in the depth direction of the piezoelectric substrate 130, which is indicated as at least the projection of the first portion 1311 in the acoustic wave propagation direction in the length direction in the acoustic wave propagation direction. The explanation of at least complete coverage may refer to the above, that is, the projection length of the second overlapping region in the length direction is equal to the projection length of the cross overlapping region in the length direction, and the projection length of the first portion 1311 may be greater than or equal to the projection length of the second overlapping region in the length direction.

It should be noted that, the embodiment of the present application is not limited to the specific structure of the first portion 1311, and referring to fig. 2 again, the extending direction of the first portion 1311 may be set to be perpendicular to the acoustic wave propagation direction of the first resonator 110. In another embodiment, as shown in fig. 5, the extending direction of the first portion 1311 may have an angle with the acoustic wave propagation direction of the first resonator 110, and the embodiment of the present application is not limited to the above angle, and the angle may be any value between greater than 0 ° and less than or equal to 90 °.

Referring again to fig. 1, the first portion 1311 may be a groove, and in another embodiment, the first portion 1311 may be an embedded structure, which may be regarded as a cavity in the piezoelectric substrate 130 and sealed to form a distinction from a groove having a cavity and opening to one side of the piezoelectric substrate 130 for the first interdigital transducer, and of course, the embedded structure may be a structure filling the groove or sealing the cavity, such as a distinction from the material of the piezoelectric substrate 130.

It is understood that the side wall of the first portion 1311 may or may not be rough, and when the side wall of the first portion 1311 is rough, the acoustic wave leaked by the second reflective grating 122 of the first reflective grating 112 is diffusely reflected at the side wall of the first portion 1311 having the rough surface, so as to reduce the mutual influence of the acoustic wave between the first resonator 110 and the second resonator 120.

The side wall of the first portion 1311 in this embodiment is regarded as an inner side wall in the thickness direction adjacent to the first reflective grating 112, and an inner side wall in the thickness direction adjacent to the second reflective grating 122.

Specifically, the sidewalls of the first portion 1311 adjacent to the first reflective grating 112 and/or the second reflective grating 122 are provided with a matte surface. For example, as shown in fig. 6, the sidewalls of first portion 1311 adjacent first reflective grating 112 are roughened, while the sidewalls of first portion 1311 adjacent second reflective grating 122 are smooth, and for example, as shown in fig. 1, the sidewalls of first portion 1311 adjacent first reflective grating 112 and second reflective grating 122 are roughened. This may allow the acoustic wave leaked from the first resonator 110 and the second resonator 120 to be diffusely reflected at the sidewalls of the groove, reducing the interaction between the first resonator 110 and the second resonator 120.

Of course, the first portions 1311 shown in fig. 1 and 6 are each a groove structure, and it is understood that the first portions 1311 may be embedded structures in other embodiments; meanwhile, with the structure in fig. 6, the acoustic wave leaked from the first reflecting grating 112 is diffusely reflected at the side wall of the first portion 1311 adjacent to the first reflecting grating 112, while the acoustic wave leaked from the second reflecting grating 122 is refracted at the side wall of the first portion 1311 adjacent to the second reflecting grating 122, and diffusely reflected if the refracted acoustic wave reaches the side wall of the first portion 1311 adjacent to the first reflecting grating 112.

It should be noted that the side wall of the first portion 1311 shown in fig. 1 and 6 is a planar structure, and in other embodiments, the side wall of the first portion 1311 may be curved or have a curved side structure.

It is understood that the embedded structure may refer to an embedded structure disposed in a groove, or the embedded structure may be roughened, and that sound waves leaking from the first reflective grating 112 adjacent to the first portion 1311 and/or the second reflective grating 122 adjacent to the first portion 1311 pass through the first portion 1311 and are diffusely reflected at a sidewall of the first portion 1311 where the roughness is disposed.

In some embodiments, at least one sidewall of the first portion 1311 is perpendicular to the plane of the piezoelectric substrate 130, and the sidewall perpendicular to the plane of the piezoelectric substrate 130 is rough, specifically, referring to fig. 1, two sidewalls of the first portion 1311 are both perpendicular to the plane of the piezoelectric substrate 130, and two sidewalls of the first portion 1311 are both rough. It should be noted that in some other embodiments, such as shown in fig. 6, only one sidewall of the first portion 1311 may be perpendicular to the plane of the piezoelectric substrate 130, and the sidewall perpendicular to the piezoelectric substrate 130 may be roughened.

It should be noted that, the side wall refers to a side surface of the first portion 1311 adjacent to the first reflective grating 112 or the second reflective grating 122, and when the side wall is perpendicular to the plane of the piezoelectric substrate 130, it is understood that the side wall should be a plane, and the plane is perpendicular to the plane of the piezoelectric substrate 130. The embodiment of the application does not limit the material of the embedded structure in detail.

In this embodiment, if the sidewall of the first portion 1311 is perpendicular to the plane of the piezoelectric substrate 130, the acoustic wave leaked from the reflective grating adjacent to the sidewall perpendicular to the plane of the piezoelectric substrate 130 reaches the sidewall and is reflected back, and the reflected acoustic wave interferes with the original resonator.

Specifically, referring to fig. 1, the acoustic wave leaked from the first reflecting grating 112 reaches a side wall adjacent to the first reflecting grating 112 in the first portion 1311, and if the side wall is a smooth plane, the acoustic wave leaked from the first reflecting grating 112 is reflected back to the first reflecting grating 112 and finally reaches the first interdigital transducer 111, so as to interfere with the acoustic wave of the first resonator 110, resulting in a performance degradation of the first resonator 110, thereby resulting in a performance degradation of the filter 10.

Therefore, when the side wall of the first portion 1311 is perpendicular to the plane of the piezoelectric substrate 130, the side wall may be configured to be rough, so that when the acoustic wave leaked from the adjacent reflecting grating reaches the side wall, diffuse reflection occurs instead of reflecting the leaked acoustic wave back, and the acoustic wave after diffuse reflection, due to losing the coherence or being destroyed, does not form coherent resonance with the resonator even if reflected back, and does not cause interference to the original resonator and the adjacent resonator.

The present embodiment does not specifically limit the longitudinal cross-sectional shape of the first portion 1311, that is, the shape of the grooves or the embedded structures, and the longitudinal cross-section herein may be understood as a cross-section of the first portion 1311 in the x-z direction. For example, it may be a rectangle with rough side walls as in fig. 1, a two-waist smooth trapezoid as in fig. 7, or some other cone, sector, oval, arc, etc., not shown.

Further, at least one concave portion 1311a and/or at least one convex portion 1311b is present in the extending direction of the first portion 1311 to increase the contact area with the leaked sound wave, thereby improving the subsequent scattering effect.

In this embodiment, the concave portion 1311a and the convex portion 1311b are formed as arbitrary side walls of the first portion, and are recessed into the first portion as concave portion 1311a, and protruding into the first portion as convex portion 1311b in the direction of the first reflective grating or the second reflective grating; the number of recesses 1311a and protrusions 1311b may be one or more, and in some embodiments may be none, i.e., the side walls of first portion 1311 may be straight in the direction of extension in a top view, and the side walls of first portion 1311 may be curved in the direction of extension in a top view when recesses 1311a and/or protrusions 1311b are present.

For example, as shown in fig. 8, in some embodiments, the first portion 1311 may present at least one recess 1311a and/or at least one protrusion 1311b in the y-direction, and in other embodiments, the first portion 1311 may present at least one recess 1311a and/or at least one protrusion 1311b in the z-direction.

In an embodiment, the longitudinal cross-sectional shape of the first portion 1311 may be any shape that does not affect the first resonator 110 and the second resonator 120, i.e., is a distance from the first resonator 110 and a distance from the second resonator 120 that is a distance from the reflective grating and interdigital transducer of the resonator and a distance from the region of the piezoelectric substrate directly below the reflective grating and interdigital transducer of the resonator.

In some embodiments, the side wall of the first portion 1311 is a plane, an included angle between the plane of the side wall of the first portion 1311 and the plane of the piezoelectric substrate 130 is between 27 ° and 165 °, and the side wall is a rough surface when the included angle between the plane of the side wall and the plane of the piezoelectric substrate 130 is 90 °, and by setting the angle, the acoustic wave leaked from the first reflective grating 112 and/or the acoustic wave leaked from the second reflective grating 122 sufficiently enter the first portion 1311, so that diffuse reflection occurs subsequently. For example, the angle between the plane of the sidewall of the first portion 1311 and the plane of the piezoelectric substrate 130 may be 27 °, 45 °, 60 °, 120 °, 165 °, etc.

In this embodiment, when the angle between the plane of the sidewall and the plane of the piezoelectric substrate 130 is not 90 °, the sidewall may be roughened.

Referring to fig. 7, in one embodiment, the piezoelectric substrate 130 may include a piezoelectric layer 133 and a substrate 134, the piezoelectric layer 133 covering the substrate 134, the piezoelectric layer 133 having a first interdigital transducer 111 and a second interdigital transducer 121 disposed on an upper surface thereof facing away from the substrate 134, the first portion 1311 being located on the piezoelectric layer 133, or the first portion 1311 being located on the piezoelectric layer 133 and extending from the piezoelectric layer 133 to the substrate 134. The piezoelectric layer 133 may be made of aluminum oxide, zinc oxide, or LiTaO ₃ 、LiNbO ₃ And organic polymers. It should be noted that the first portion 1311 may also penetrate the piezoelectric substrate 130. This may allow the first portion 1311 to have a larger range in space, and may further allow the scattering effect of the acoustic wave leaked from the first resonator 110 and/or the second resonator 120 to be better when diffusely reflected.

Of course, the above is merely exemplary, and in other embodiments, the piezoelectric substrate 130 may include only the piezoelectric layer 133, or include intermediate layers between the piezoelectric layer 133 and the substrate 134 in addition to the piezoelectric layer 133 and the substrate 134, and the number of the intermediate layers may be one or more, which is not particularly limited herein.

In an embodiment, the first portion 1311 is at least located in the piezoelectric layer 133, and the first portion 1311 may be exposed to the piezoelectric layer 133 or located inside the piezoelectric layer 133, where the depth of the first portion 1311 is greater than 0.5 times the spatial period of the first interdigital transducer 111 or the depth of the first portion 1311 is greater than 0.5 times the spatial period of the second interdigital transducer 121, taking the spatial period of the first interdigital transducer 111 as an example, the total length of the first finger 1113 and the adjacent two first finger 1113 in the x direction is defined as the spatial period of the first interdigital transducer 111, and the spatial period of the second interdigital transducer 112 is the same. If the depth of the first portion 1311 is too small, that is, the position occupied in the depth direction of the piezoelectric layer 133 is insufficient, because the intensity of the sound wave in the piezoelectric layer 133 is large, some sound waves cannot enter the first portion 1311, and the diffuse reflection effect of the sound wave leaked from the subsequent first reflective grating 112 and/or the second reflective grating 122 is also affected.

Further, with continued reference to fig. 7, in one embodiment, the piezoelectric substrate 130 may further include: the number of the intermediate layers 135 may be one or more, the intermediate layers 135 may be a temperature compensation layer (temperature compensation layer), a dielectric layer, or the like, the intermediate layers 135 are disposed on a side of the substrate 134 facing away from the first surface, the piezoelectric layer 133 covers the intermediate layers 135, the first portion 1311 is disposed on the piezoelectric layer 133, or the first portion 1311 is disposed on the piezoelectric layer 133 and extends from the piezoelectric layer 133 to the intermediate layers 135, or the first portion 1311 is disposed on the piezoelectric layer 133 and extends from the piezoelectric layer 133 to the substrate 134. It should be noted that the first portion 1311 may also penetrate the piezoelectric substrate 130.

In this embodiment, a dielectric film may be covered on the surfaces of the first resonator 110 and/or the second resonator 120 and the adjacent piezoelectric layer 133 together to isolate the first resonator 110 and/or the second resonator 120 from the external environment, as required. Or other dielectric functional layers such as silicon dioxide (SiO) may be formed over the piezoelectric layer 133 and the first resonator 110 and/or the second resonator 120 ₂ ) Silicon nitride, aluminum oxide, and the like.

In another embodiment, the piezoelectric substrate 130 may include: the piezoelectric layer 133 covers the substrate 134, the upper surface of the piezoelectric layer 133 facing away from the substrate 134 is provided with the first interdigital transducer 111 and the second interdigital transducer 121, and the depth of the first portion 1311 is at least greater than the thickness of the piezoelectric layer 133. That is, in this embodiment, the first portion 1311 may also be a cavity structure with a closed top of the groove. It should be noted that the first portion 1311 may also penetrate the piezoelectric substrate 130.

Referring again to fig. 7, in some embodiments, the piezoelectric substrate 130 may include: facing away from the first surface of the first interdigital transducer 111 and the second interdigital transducer 121, the first surface is roughened, which can be regarded as a lower surface of the bottommost layer in the thickness direction of the piezoelectric substrate 130, and the scattering structure further comprises a second portion 1312, the second portion 1312 comprising the first surface, i.e. the roughened first surface is regarded as the second portion 1312. In this embodiment, the acoustic wave leaking from the first reflection grating 112 can be further guided to the second portion 1312 by the first portion 1311 for diffuse reflection, and the effect of eliminating the acoustic wave is improved.

In this embodiment, the first surface may be regarded as facing away from the first interdigital transducer 111 and the second interdigital transducer 121, and on the lowermost surface of the first resonator 110 or the second resonator 120, for example, when the piezoelectric substrate of the first resonator 110 or the second resonator 120 is a multilayer structure, then in the depth direction of the piezoelectric substrate, the first surface is a lower bottom surface facing away from the structure of the lowermost layer of the first interdigital transducer 111 and the second interdigital transducer 121.

Specifically, as above, if the piezoelectric substrate includes the piezoelectric layer 133 and the substrate 134, the bottom surface of the substrate 134 facing away from the first interdigital transducer 111 and the second interdigital transducer 121 is the first surface, and if the piezoelectric substrate further includes the intermediate layer, the first surface is still the bottom surface of the piezoelectric substrate facing away from the first interdigital transducer 111 and the second interdigital transducer 121, that is, the bottom surface of the substrate 134 facing away from the first interdigital transducer 111 and the second interdigital transducer 121.

Specifically, for example, when the first portion 1311 is a groove, due to the presence of the groove structure, when the first resonator 110 excites an acoustic wave, the acoustic wave may cross the first reflective grating 112, but at the groove the acoustic wave will be refracted to propagate toward the piezoelectric substrate 130, while for an acoustic wave propagating toward the piezoelectric substrate 130 (i.e., having a-z component in the propagation direction), at least a partial region of the first surface of the piezoelectric substrate 130 may be provided with a roughened bottom surface to form a second portion 1312, the leaked acoustic wave being diffusely reflected at the second portion 1312, such that the acoustic wave leaked by the first resonator 110 or the second resonator 120 is diffusely reflected to reduce its re-reflection at the piezoelectric substrate 130 to be absorbed by the second resonator 120 or the first resonator 110, causing deterioration in device performance, thereby reducing mutual interference between the first resonator 110 and the second resonator 120.

For example, referring to fig. 7, in the present embodiment, the first portion 1311 is a groove, and the sound wave emitted by the first resonator 110 may be guided by the first portion 1311 to the second portion 1312 and diffusely reflected at the second portion.

Referring to fig. 6, in the embodiment, the first portion 1311 is a groove, and a surface of the groove adjacent to the first resonator 110 is a rough surface, at this time, a part of sound waves emitted by the first resonator 110 may be diffusely reflected by the first portion 1311, and another part of sound waves may be guided by the first portion 1311 to the second portion 1312 and diffusely reflected by the second portion 1312, so that a diffuse reflection effect of the scattering structure may be further improved, so that mutual interference between adjacent resonators is further reduced, and performance of the filter is improved.

Based on the above embodiment, the scattering structure in this embodiment may be divided into various forms, the first form is that the side walls of the first portion 1311 are all rough, in this case, the scattering structure may only have the first portion 1311, that is, the first surface of the piezoelectric substrate 130 is a smooth plane, and the first surface of the smooth plane is not the second portion, and of course, to further improve the diffuse reflection effect, the second portion 1312 may also be provided; the second is that the sidewalls of the first portion 1311 are not rough, and in this case, the sidewalls of the first portion 1311 cannot be perpendicular to the plane of the piezoelectric substrate 130, and the second portion 1312 must be present; the third is that at least one side wall of the first portion 1311 is a plane perpendicular to the plane of the piezoelectric substrate 130, and the plane perpendicular to the plane of the piezoelectric substrate 130 is a rough surface, if both side walls of the first portion 1311 are planes perpendicular to the plane of the piezoelectric substrate 130 at this time, the second portion 1312 may not be provided, but similarly, in order to further enhance the diffuse reflection effect, the second portion 1312 may also be provided, and if only one side wall of the first portion 1311 is a plane perpendicular to the plane of the piezoelectric substrate 130, and the other side is not a plane perpendicular to the plane of the piezoelectric substrate 130, and is of a smooth structure, the second portion 1312 must be provided at this time.

The embodiment of the application also provides a filter, which comprises: a first resonator and a second resonator. The first resonator comprises a first interdigital transducer and first reflecting grids arranged on two sides of the first interdigital transducer. The second resonator comprises a second interdigital transducer and second reflecting grids arranged at two sides of the second interdigital transducer, the second resonator is adjacent to the first resonator, and the second resonator has an overlapping area with the first resonator in the acoustic wave propagation direction of the first resonator; wherein, the first resonator and the second resonator share a piezoelectric substrate, a scattering structure is arranged in the piezoelectric substrate, and the scattering structure is provided with a rough surface; the sound wave leaked from the first reflecting grating adjacent to the scattering structure and/or the second reflecting grating adjacent to the scattering structure passes through the scattering structure and is diffusely reflected at the side wall of the scattering structure provided with the rough surface.

The features of the first resonator, the second resonator, and the piezoelectric substrate in the embodiment of the present application are the same as those of the foregoing embodiments, and reference may be made to the foregoing embodiments, which are not described herein.

By arranging the scattering structure in the piezoelectric substrate, the scattering structure is used for carrying out diffuse reflection on the sound wave leaked from the first reflecting grating in the first resonator and/or carrying out diffuse reflection on the sound wave leaked from the second reflecting grating in the second resonator, so that the mutual influence of the sound waves between the first resonator and the second resonator is reduced, and the performance of the filter is improved.

The embodiment of the application also provides a filter, which comprises: a first resonator, a second resonator, and a scattering structure. The first resonator comprises a first interdigital transducer and first reflecting grids arranged on two sides of the first interdigital transducer. The second resonator comprises a second interdigital transducer and second reflecting grids arranged at two sides of the second interdigital transducer, the second resonator is adjacent to the first resonator, and the second resonator has an overlapping area with the first resonator in the acoustic wave propagation direction of the first resonator; the piezoelectric substrate at least comprises a piezoelectric layer and a substrate, the piezoelectric layer covers the substrate, and a first interdigital transducer and a second interdigital transducer are arranged on the upper surface of the piezoelectric layer, which is away from the substrate. The scattering structure is located within the piezoelectric layer, or the scattering structure is located within the piezoelectric layer and within the substrate, the scattering structure being for diffusely reflecting sound waves leaking from the first reflection grating and/or for diffusely reflecting sound waves leaking from the second reflection grating.

By arranging the first resonator and the second resonator on the same piezoelectric substrate and arranging the scattering structure in the piezoelectric substrate, the scattering structure is used for carrying out diffuse reflection on the sound wave leaked from the first reflecting grating in the first resonator and/or carrying out diffuse reflection on the sound wave leaked from the second reflecting grating in the second resonator, so that the mutual influence of the sound waves between the first resonator and the second resonator is reduced, and the performance of the filter is improved.

The embodiment of the application also provides electronic equipment, which can comprise any filter.

The electronic device may be a multiplexer, a duplexer, a radio frequency front end, etc. manufactured based on the filter, or may be a tablet computer, a notebook computer, a navigator, a mobile phone, etc. obtained based on the filter, which is not particularly limited in this embodiment.

According to the electronic device provided by the embodiment of the application, the first resonator and the second resonator are arranged on the same piezoelectric substrate, and the scattering structure is arranged in the piezoelectric substrate, so that the scattering structure is used for carrying out diffuse reflection on the sound wave leaked from the first reflecting grating in the first resonator and/or carrying out diffuse reflection on the sound wave leaked from the second reflecting grating in the second resonator, the mutual influence of the sound waves between the first resonator and the second resonator is reduced, and the performance of the filter is improved.

The following description is made in connection with three comparative examples and examples provided by the present application:

first comparative example:

referring to fig. 9-13, a first comparative example is a resonator R1 in which the piezoelectric substrate includes a substrate 134, an intermediate layer, from bottom to top as shown in fig. 9The piezoelectric layer 133 includes an interdigital transducer 11 and reflective gratings 12 positioned on both sides of the interdigital transducer, wherein the substrate is a Si substrate with a thickness of 5 μm (micrometers). The middle layer is SiO ₂ The number of the intermediate layers 135 is not limited, and as in FIG. 10 and FIG. 12, there are 2 intermediate layers, the thickness of the two intermediate layers is 0.5 μm and 0.7 μm, respectively, and the piezoelectric layer is LT piezoelectric layer, i.e. LiTaO ₃ The piezoelectric layer of material is 0.6 μm thick, and it should be understood that the metal electrode 1 located above the piezoelectric layer 133 in fig. 10 includes an interdigital transducer and a reflective grating, and the fingers on both sides of the metal electrode 1 in fig. 10 and 12 are regarded as reflective gratings, and the fingers in the middle region are regarded as interdigital transducers.

The metal electrode 1 of the resonator R1 is an aluminum electrode and has a thickness of 0.17 μm. The interdigital transducer in resonator R1 has a spatial period of 1 μm and a duty cycle of 0.5. The number of fingers of the reflection grating in the resonator R1 is 20, and the reflection grating is set to be grounded. The interdigital transducer in the resonator R1 has 61 fingers, and specifically consists of 31 first fingers and 30 second fingers. The first finger strips and the second finger strips are alternately arranged to form an interdigital structure. The first finger strips at the leftmost end and the right end are closely adjacent to the first reflecting grating. The first finger is configured as a signal terminal and the second finger is configured as ground. The outside of the reflective grating also contains a 30 μm blank area.

Fig. 10 shows the mechanical energy storage distribution of the non-waveguide mode of the resonator R1 of the first comparative example. In fig. 10, the brighter the color, which means a higher energy distribution, the visible non-waveguide mode is mostly confined in resonator R1, but there is still a small portion of energy leaking out, which can interfere with the adjacent resonator.

Fig. 11 shows a mechanical energy storage distribution curve of the non-waveguide mode of the resonator R1 of the first comparative example in the acoustic propagation direction.

Fig. 12 shows a mechanical energy storage distribution curve of the waveguide mode of the resonator R1 of the first comparative example. It should be noted that, the waveguide mode is a mode, the acoustic wave can propagate infinitely and cannot dissipate by itself, and the visible waveguide mode has strong energy after passing through the reflective grating, and in the filter, the adjacent resonators are disturbed.

Fig. 13 shows a mechanical energy storage distribution curve of the waveguide mode of the resonator R1 of the first comparative example in the acoustic propagation direction.

The abscissa in fig. 11 and 13 corresponds to the positional relationship of the resonator R1 in the acoustic propagation direction in fig. 9 and 10, and the ordinate ρe is the mechanical energy storage amount of the piezoelectric layer, and the larger the ordinate value is, the larger the mechanical energy storage is, which proves that the acoustic wave energy of the resonator corresponding position is larger, and a.u. is an arbitrary unit.

The region of abscissa 0 to 100 in fig. 11 corresponds to the position of the piezoelectric layer region directly under the finger in fig. 10, that is, the abscissa 0 corresponds to the piezoelectric layer region directly under the leftmost finger in fig. 10, the abscissa 100 corresponds to the piezoelectric layer region directly under the rightmost finger in fig. 10, and as can be seen in fig. 10 and 11, the mechanical energy storage of the finger in the middle region, that is, the region of the interdigital transducer, which is not the waveguide mode is the largest, gradually decreases toward both sides of the interdigital transducer, and it should be noted that the region of the piezoelectric layer of fig. 11 where only a part of the region is shown in fig. 10 is not referred to as actual mechanical energy storage, but is conveniently indicated in fig. 11, corresponds to the piezoelectric layer region shown in fig. 12 to set the mechanical energy storage of the relevant region to 0, such as the region after the abscissa of more than 120 and the region before the abscissa of fig. 11 is less than-20.

Likewise, the region of abscissa 0 to 100 in fig. 13 corresponds to the position of the piezoelectric layer region directly under the finger in fig. 12, that is, the abscissa 0 corresponds to the piezoelectric layer region directly under the leftmost finger in fig. 11, the abscissa 100 corresponds to the piezoelectric layer region directly under the rightmost finger in fig. 12, the region of abscissa 100 to 120 corresponds to the piezoelectric layer region going from the rightmost finger to the right in fig. 12, the region of abscissa-20 to 0 corresponds to the piezoelectric layer region going from the leftmost finger to the left in fig. 12, it is known in fig. 12 and 13 that the waveguide mode spreads toward both sides of the interdigital transducer with little energy consumption and still a large energy, and likewise, the region where the mechanical energy storage is 0 shown in fig. 13 does not refer to the actual mechanical energy storage, but is a convenient illustration in fig. 13, the region corresponding to the piezoelectric layer region shown in fig. 12 is set to 0 for the mechanical energy storage of the relevant region, as the region is larger than the region of abscissa 120 and beyond-20 in fig. 13.

As can be seen from fig. 9-13, the reflective grating in R1 cannot fully confine energy in the region of the interdigital transducer, and some of the energy passes over the reflective grating of R1 and enters the region other than the resonator R1, forming energy leakage, which can affect other adjacent resonators.

Fig. 14 shows a harmonic admittance curve of the resonator R1 in the comparative example. In the harmonic admittance graph, the abscissa is frequency, the unit GHz, the ordinate is admittance, the unit dB, the wave crest is a resonance point, the wave trough is an anti-resonance point, the ripple between the resonance point and the anti-resonance point proves that the interference occurs, and the performance of the first resonator can be ensured if the curve between the resonance point and the anti-resonance point is smooth. As is clear from the figure, since only one resonator is provided in the first comparative example, no other sound wave has an influence on the resonator.

Second comparative example:

referring to fig. 15 and 17, in the second comparative example, two resonators R1 in the first comparative example are horizontally combined, and two resonators R1 are adjacent to each other and have an overlapping region, and compared with the filter provided by the present application, no scattering structure is disposed between the two resonators. The resonator on the left side may be referred to as a first resonator 110, the resonator on the right side may be referred to as a second resonator 120, and the specific structures of the first resonator 110 and the second resonator 120 may refer to the resonator R1 in the first comparative example, which is not described herein.

Fig. 16 shows the mie stress distribution of the waveguide mode of the first resonator 110 when the first resonator 110 is excited and the second resonator 120 is not excited in the second comparative example.

Fig. 17 shows a harmonic admittance curve of the first resonator 110 when the first resonator 110 is excited and the second resonator 120 is also excited in the second comparative example.

In this embodiment, the mie stress distribution diagram is used to show the mie stress distribution diagram in the filter, in which the brighter the color, the larger the corresponding acoustic energy is, and the energy distribution area and the energy distribution intensity of the acoustic wave can be determined by the mie stress distribution diagram.

Of course, the waveguide mode is taken as an example in the present embodiment, and acoustic waves of other modes may be used in other embodiments, and the present invention is not limited in particular.

As can be seen from fig. 16, the energy of the first resonator 110 is transferred to the second resonator 120, thereby interfering with the operation of the second resonator 120.

As can be seen from fig. 17, several ripples appear between the resonance point and the antiresonance point, which is a result of the first resonator 110 and the second resonator 120 interfering with each other.

Of course, although not shown in fig. 15 and 16, the lower surface of the substrate 134 in the thickness direction of the substrate 134 in fig. 15 and 16 may be roughened, that is, may be regarded as having the second portion, and may be non-roughened, that is, may not have the second portion.

Third comparative example:

referring to fig. 18-20 together, fig. 18 shows a schematic structural diagram of a third comparative example in which two resonators R1 in the first comparative example are horizontally combined as well, two resonators R1 are adjacent to each other and there is a slave overlap region, in this comparative example, the left side resonator may be referred to as a first resonator 110 and the right side resonator may be referred to as a second resonator 120, unlike the second comparative example in which a groove is provided on a piezoelectric substrate, and the groove is provided on a piezoelectric substrate region between the first resonator 110 and the second resonator 120.

The filter in the third comparative example is provided with a groove in the middle region of the two resonators, compared with the second comparative example. Specifically, in the third comparative example, the piezoelectric layer and the intermediate layer in the middle 4 μm wide range in the second comparative example were removed, and a groove having a rectangular cross section was formed therein, the groove having a depth of 1.1 μm and a width of 4 μm.

Fig. 19 shows the mie stress distribution of the waveguide mode of the first resonator 110 when the first resonator 110 is excited and the second resonator 120 is not excited in the third comparative example.

Fig. 20 shows a harmonic admittance curve of the first resonator 110 when the first resonator 110 is excited and the second resonator 120 is not excited in the third comparative example.

As can be seen from fig. 19, in the area between the groove and the adjacent first reflective grating, the area in fig. 19 is significantly brighter than the corresponding area in fig. 16, that is, the area between the groove and the adjacent first reflective grating in fig. 19 has a larger mie stress, because the side wall of the groove is a plane perpendicular to the piezoelectric substrate, and the plane is smooth, the acoustic wave leaked from the first reflective grating by the first resonator 110 is reflected at the side wall of the groove, and the reflected energy reaches the area between the groove and the adjacent first reflective grating, resulting in a large mie stress in the area.

As can be seen from fig. 20, there is a ripple between the resonance point and the antiresonance point, but unlike in the second comparative example, a large ripple occurs near the resonance point, which is caused by the sound wave reflected back by the grooves, which seriously affects the performance of the first resonator, and it is seen that the arrangement of grooves with side walls perpendicular to the piezoelectric substrate and smooth side walls in two adjacent resonators causes interference with the resonator itself.

Also, although not shown in fig. 18 and 19, the lower surface of the substrate 134 in the thickness direction of the substrate 134 in fig. 18 and 19 may be roughened, that is, may be regarded as having the second portion, and may be non-roughened, that is, may not have the second portion.

First embodiment:

referring to fig. 21, the first embodiment provides that two resonators R1 of the first comparative example are also arranged in a horizontal combination, two resonators R1 are adjacent to each other with an overlapping area therebetween, and the first resonator 110 and the second resonator 120 are arranged on the same piezoelectric substrate. The piezoelectric substrate 134 is provided with a scattering structure, which is a groove and a matte surface provided on a first surface of the piezoelectric substrate 134, and it is noted that although the lower surface of the substrate 134 in the thickness direction of the substrate 134 is not shown in fig. 21 as a matte surface, it is understood that the lower surface of the substrate 134 in the thickness direction of the substrate 134 in fig. 21 is a matte surface, that is, the first surface should be a matte surface, and the groove is provided in the region of the piezoelectric substrate 130 between the first resonator 110 and the second resonator 120. The grooves serve to guide the acoustic wave leaked from the first resonator 110 and/or the second resonator 120 to the rough surface for diffuse reflection. Specifically, in the present embodiment, the side walls of the groove are inclined to the plane of the piezoelectric substrate 130 so that the cross section of the groove is trapezoidal, the depth of the groove is 1.1 μm, the width of the groove bottom is 2 μm, and the width of the groove top is 4 μm.

The piezoelectric substrate 130 includes a substrate 134, an intermediate layer 135 and a piezoelectric layer 133, the substrate 134 is a Si substrate with a thickness of 5 μm, the thickness of the two intermediate layers is 0.5 μm and 0.7 μm, respectively, the thickness of the intermediate layer is 0.5 μm, and the material of the piezoelectric layer 133 is LT, i.e., liTaO ₃ The thickness of the material is 0.6 μm.

The electrode patterns of the first resonator 110 and the second resonator 120 are aluminum electrodes, i.e., the reflective grating and the interdigital transducer are made of aluminum, and have a thickness of 0.17 μm. The structure of the first resonator 110 is set to be identical to that of the second resonator 120.

In the first resonator 110, the first interdigital transducers each have a spatial period of 1 μm and a duty cycle of 0.5.

The number of fingers of the first reflective grating is 20, and the first reflective grating is set to be grounded. The number of fingers of the first transducer is 61, and the first transducer is composed of 31 first fingers and 30 second fingers.

The first finger strips and the second finger strips are alternately arranged to form an interdigital structure. The first finger strips at the leftmost end and the right end are closely adjacent to the first reflecting grating. The first finger is configured as a signal terminal and the second finger is configured as ground.

Fig. 21 shows the mie stress distribution of the waveguide mode of the first resonator when the first resonator is excited in the first embodiment.

Fig. 22 shows the harmonic admittance curves of the first resonator when the first resonator is excited in the first embodiment.

As can be seen, the curve is smooth between the resonance point and the antiresonance point. This is because the grooves reduce the reflected sound waves and guide the leaked sound waves elsewhere, thus reducing the influence of the reflected sound waves on the first resonator, while, as can be seen from fig. 22, there is little mie stress in the region of the piezoelectric substrate 130 under the second resonator 120, whereby it is seen that by means of the isosceles trapezoid grooves, the mutual interference between the first resonator and the second resonator can be reduced while the deterioration of the first resonator itself is reduced.

Referring to fig. 23, fig. 23 shows forward voltage gain graphs, that is, dB (S21) curves (V Shape Sink in fig. 23) of the second comparative example (W/O Sink in fig. 23), the third comparative example (Rectangle Sink in fig. 23) and the first embodiment, which may represent the influence of different frequencies on adjacent resonators, the larger the ordinate value, the larger the influence/interference on the adjacent resonators at the frequency.

In the figure, the abscissa indicates the frequency GHz and the ordinate indicates the intensity dB. As can be seen from the graph, the average value of dB (S21) of the second comparative example is-44.6 dB, and the maximum value is about-10 dB; the average value of dB (S21) of the first specific embodiment is-70.3 dB, and the maximum value is about-20 dB. The average value of dB (S21) of the first embodiment is-66.5 dB, and the maximum value is-30 dB. The average value may reflect the overall isolation effect, and the maximum value may reflect the isolation effect for a specific frequency band. It can be obtained that both the rectangular grooves and the isosceles trapezoid grooves can effectively inhibit mutual interference between resonators. The average inhibition effect of the rectangular groove is better than that of the isosceles trapezoid groove, but the rectangular groove can reflect sound waves back to interfere with the resonator of the rectangular groove, and the maximum value of the rectangular groove is larger than that of the isosceles trapezoid groove, so that when the side wall of the first part is a plane perpendicular to the plane of the piezoelectric substrate, the side wall of the first part is a rough plane, interference between the two resonators can be prevented, and the occurrence of the situation that the leakage sound waves reflect the resonator of the rectangular groove.

In summary, according to the filter and the electronic device provided by the embodiments of the present application, the first resonator and the second resonator are disposed on the same piezoelectric substrate, and the scattering structure is disposed in the piezoelectric substrate, so that the scattering structure is used to diffusely reflect the sound wave leaked from the first reflecting grating in the first resonator and/or diffusely reflect the sound wave leaked from the second reflecting grating in the second resonator, thereby reducing the interaction between the first resonator and the second resonator, and improving the performance of the filter.

In the present application, the terms "mounted," "connected," and the like should be construed broadly unless otherwise specifically indicated or defined. For example, the connection can be fixed connection, detachable connection, integral connection or transmission connection; may be directly connected or indirectly connected through an intermediate medium. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

Furthermore, the terms "first," "second," and the like, are used merely for distinguishing between descriptions and not for understanding as a specific or particular structure. The description of the term "some embodiments" means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In the present application, the schematic representations of the above terms are not necessarily for the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples of the present application and features of various embodiments or examples may be combined and combined by those skilled in the art without contradiction.

The above embodiments are only for illustrating the technical solution of the present application, and are not limiting thereof; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and they should be included in the protection scope of the present application.

Claims

1. A filter, comprising:

the first resonator comprises a first interdigital transducer and first reflecting grids arranged on two sides of the first interdigital transducer; and

the second resonator comprises a second interdigital transducer and second reflecting grids arranged on two sides of the second interdigital transducer, the second resonator is adjacent to the first resonator, and the second resonator has an overlapping area with the first resonator in the acoustic wave propagation direction of the first resonator; wherein,,

the first resonator and the second resonator share a piezoelectric substrate, and a scattering structure is arranged in the piezoelectric substrate and used for carrying out diffuse reflection on sound waves leaked from the first reflecting grating and/or carrying out diffuse reflection on sound waves leaked from the second reflecting grating.

2. The filter of claim 1, wherein the scattering structure comprises: a first portion at least partially located between the first resonator and the second resonator, a projection of the first portion in the direction of propagation of the acoustic wave at least partially overlapping a projection of the overlap region in the direction of propagation of the acoustic wave.

3. The filter of claim 2, wherein the projection of the first portion in the direction of propagation of the acoustic wave covers at least the projection of the overlap region in the direction of propagation of the acoustic wave.

4. The filter of claim 2, wherein the first interdigital transducer comprises a first crossover region and the second interdigital transducer comprises a second crossover region, the first crossover region and the second crossover region having a crossover overlap region in the direction of acoustic wave propagation, a projection of the first portion in the direction of acoustic wave propagation at least partially overlapping a projection of the crossover overlap region in the direction of acoustic wave propagation.

5. The filter of claim 4, wherein the projection of the first portion in the direction of propagation of the acoustic wave covers at least the projection of the cross overlap region in the direction of propagation of the acoustic wave.

6. The filter of claim 2, wherein the first portion is a groove or an embedded structure.

7. The filter of claim 2, wherein a sidewall of the first portion adjacent to the first reflective grating and/or the second reflective grating is roughened.

8. The filter of claim 2, wherein at least one sidewall of the first portion is perpendicular to the plane of the piezoelectric substrate and a sidewall perpendicular to the plane of the piezoelectric substrate is roughened.

9. A filter according to claim 2, wherein the longitudinal cross-section of the first portion is rectangular or trapezoidal or tapered or fan-shaped or oval or arcuate.

10. The filter of claim 2, wherein an angle between a plane of the sidewall of the first portion and a plane of the piezoelectric substrate is between 27 ° and 165 °.

11. The filter of any of claims 2-10, wherein the piezoelectric substrate includes a first surface facing away from the first interdigital transducer and the second interdigital transducer, the first surface being roughened, the scattering structure further comprising: a second portion including the first surface.

12. The filter of claim 2, wherein the piezoelectric substrate comprises: the piezoelectric device comprises a piezoelectric layer and a substrate, wherein the piezoelectric layer covers the substrate, the first interdigital transducer and the second interdigital transducer are arranged on the upper surface of the piezoelectric layer, which is away from the substrate, and the first part is positioned on the piezoelectric layer or the first part is positioned on the piezoelectric layer and extends from the piezoelectric layer to the substrate.

13. The filter of claim 12, wherein the piezoelectric substrate further comprises an intermediate layer disposed on an upper surface of the substrate facing away from the first surface, and wherein the intermediate layer is covered by the piezoelectric layer, wherein the first portion is located on the piezoelectric layer, or wherein the first portion is located on the piezoelectric layer and extends from the piezoelectric layer to the intermediate layer, or wherein the first portion is located on the piezoelectric layer and extends from the piezoelectric layer to the substrate.

14. The filter according to claim 2, characterized in that the first portion has at least one recess and/or at least one protrusion in the direction orthogonal to the direction of propagation of the sound wave.

15. The filter of claim 2, wherein the depth of the first portion is greater than 0.5 times the spatial period of the first interdigital transducer or 0.5 times the spatial period of the second interdigital transducer.

16. The filter of claim 2, wherein the first portion extends through the piezoelectric substrate.

17. The filter of claim 2, wherein a width of the first portion in the acoustic wave propagation direction is greater than or equal to 100nm.

18. The filter of claim 2, wherein a distance between the first portion and the first reflective grating is greater than or equal to 100nm and/or a distance between the first portion and the second resonator is greater than or equal to 100nm.

19. A filter, comprising:

the second resonator comprises a second interdigital transducer and second reflecting grids arranged on two sides of the second interdigital transducer, the second resonator is adjacent to the first resonator, and the second resonator has an overlapping area with the first resonator in the acoustic wave propagation direction of the first resonator;

wherein the first resonator and the second resonator share a piezoelectric substrate, a scattering structure is arranged in the piezoelectric substrate, and the scattering structure is provided with a rough surface; the sound wave leaked from the first reflecting grating adjacent to the scattering structure and/or the second reflecting grating adjacent to the scattering structure passes through the scattering structure and is diffusely reflected on the side wall of the scattering structure, which is provided with a rough surface.

20. A filter, comprising:

the first resonator comprises a first interdigital transducer and first reflecting grids arranged on two sides of the first interdigital transducer;

the first resonator and the second resonator share a piezoelectric substrate, the piezoelectric substrate at least comprises a piezoelectric layer and a substrate, the piezoelectric layer covers the substrate, and the first interdigital transducer and the second interdigital transducer are arranged on the upper surface of the piezoelectric layer, which is away from the substrate; and

a scattering structure within the piezoelectric layer or within the piezoelectric layer and within the substrate for diffusely reflecting sound waves leaking from the first reflective grating and/or for diffusely reflecting sound waves leaking from the second reflective grating.

21. An electronic device comprising the filter of any one of claims 1-20.