Acoustic wave device and manufacturing method thereof
By introducing non-regular structures on the edges of the active region in voice wave devices to prevent parallel edges, the device suppresses standing wave formation, thereby enhancing performance and quality factors.
Patent Information
- Application Number
- CN202510256530.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-05
- Publication Date
- 2025-07-15
AI Technical Summary
In existing acoustic wave devices, transverse shear waves reflect back and forth between mutually parallel sides to form standing waves, affecting the communication effect of communication devices.
An irregular structure is provided on the closed pattern contour edges of the active region of the acoustic wave device, so that the slopes of any two contour edges are different or the tangent slopes of the tangent point on any contour edge are different from the slopes of other contour edges, avoiding back and forth reflection of transverse shear waves.
By changing the propagation direction of the transverse shear wave, the formation of standing waves is suppressed, and the performance of acoustic wave devices is improved, especially the quality factor and effective electromechanical coupling coefficient.
Smart Images
Figure CN120320731A_ABST
Abstract
Description
Technical Field
[0001] Embodiments of the present disclosure relate to the field of acoustic wave devices, and in particular, to an acoustic wave device and a manufacturing method thereof. Background Art
[0002] In communication devices such as mobile phones that are widely used, acoustic wave devices using acoustic waves are usually included as filters for communication devices. As an example of an acoustic wave device, there are surface acoustic wave (SAW) devices or bulk acoustic wave (BAW) devices, etc. The performance of the acoustic wave device affects the communication effect of the communication device.
[0003] Therefore, how to improve the performance of the acoustic wave device has become an urgent technical problem to be solved. Summary of the Invention
[0004] According to a first aspect of the embodiments of the present disclosure, an acoustic wave device is provided. The acoustic wave device includes a reflection structure, a first electrode layer, a piezoelectric layer, and a second electrode layer stacked in sequence. The overlapping portions of the reflection structure, the first electrode layer, the piezoelectric layer, and the second electrode layer in the stacking direction form an active region. Wherein, the orthographic projection of the active region is a closed figure, and irregular structures are provided on the contour edges of the closed figure. The irregular structures make the slopes of any two of the contour edges of the closed figure different, or the irregular structures make the tangent slope of the tangent point on any one of the contour edges of the closed figure different from the slopes of the other contour edges of the closed figure, or the irregular structures make the tangent slopes of any two tangent points on the contour edges of the closed figure different from each other.
[0005] In some embodiments, the closed figure is formed by connecting at least one of the contour edges, and the irregular structures are provided on at least one of the contour edges.
[0006] In some embodiments, the contour edges of the closed figure include at least one of a straight edge and a curved edge.
[0007] In some embodiments, the irregular structure includes at least one n-sided polygon, where n is an integer greater than 2.
[0008] In some embodiments, the slopes of any two sides of the n-sided polygon are different, or the tangent slope of the tangent point on any one side of the n-sided polygon is different from the slopes of the other sides of the n-sided polygon, or the tangent slopes of the tangent points on any one side of the n-sided polygon are different from the tangent slopes of the tangent points on the other sides of the n-sided polygon.
[0009] In some embodiments, the sides of the n-sided polygon include at least one of straight sides and curved sides.
[0010] In some embodiments, the sum of the side length of the n-sided polygon and the spacing between adjacent n-sided polygons is less than 1 / 5 of the side length of the contour side where the irregular structure is located.
[0011] In some embodiments, the sum of the side length of the n-sided polygon and the spacing between adjacent n-sided polygons is greater than 4 μm.
[0012] In some embodiments, the irregular structure includes: a depression facing the inside of the active portion; and / or, a protrusion facing the outside of the active portion.
[0013] In some embodiments, the irregular structure is provided on the contour side of at least one of the reflective structure, the first electrode layer, the piezoelectric layer, and the second electrode layer.
[0014] In some embodiments, the irregular structure further includes a frame structure, a cantilever structure, or a bridge structure provided on the edge of at least a part of the second electrode layer.
[0015] According to a second aspect of the embodiments of the present disclosure, there is provided a method for manufacturing an acoustic wave device, the manufacturing method including: forming a reflective structure, a first electrode layer, a piezoelectric layer, and a second electrode layer stacked in sequence, wherein the overlapping portions of the reflective structure, the first electrode layer, the piezoelectric layer, and the second electrode layer in the stacking direction constitute an active region; forming an irregular structure at the edge of the active region, wherein the positive projection of the active region is a closed figure, and the irregular structure is formed on the contour side of the closed figure; the irregular structure makes the slopes of any two of the contour sides of the closed figure different, or the irregular structure makes the tangent slope of the tangent point on any one of the contour sides of the closed figure different from the slopes of the other contour sides of the closed figure, or the irregular structure makes the tangent slopes of any two tangent points on the contour side of the closed figure different from each other.
[0016] In the embodiments of the present disclosure, by providing an irregular structure on the contour edge of a closed figure corresponding to an active region, the irregular structure can make any two contour edges of the closed figure non-parallel (i.e., the closed figure has no parallel edges), or make the tangent line passing through the tangent point on any one contour edge of the closed figure non-parallel to the other contour edges of the closed figure, or make the tangent line passing through the tangent point on any one contour edge of the closed figure non-parallel to the tangent line passing through the tangent points on the other contour edges of the closed figure. That is, the irregular structure can make the edges of the active region have no parallel edges, thereby changing the propagation direction of the transverse shear wave and suppressing the formation of standing waves due to the back-and-forth reflection of the transverse shear wave in the acoustic wave device, which is beneficial to improving the performance of the acoustic wave device. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In the drawings, unless otherwise specified, the same reference numerals throughout the several views refer to the same or like parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in accordance with the present application and should not be regarded as limiting the scope of the present application.
[0018] Figure 1A is a schematic cross-sectional view of an acoustic wave device shown in an exemplary embodiment;
[0019] Figure 1B is a schematic diagram of the acoustic waves generated in an acoustic wave device shown in an exemplary embodiment;
[0020] Figure 1C is a schematic diagram of the orthographic projection of the active region of an acoustic wave device shown in an exemplary embodiment;
[0021] Figure 2 is a schematic diagram of the orthographic projection of the active region of an acoustic wave device shown in an embodiment of the present disclosure;
[0022] Figure 3 is a schematic diagram of the shape of an n-sided polygon shown in an embodiment of the present disclosure;
[0023] Figure 4 is a schematic diagram of the orthographic projection of the active region of another acoustic wave device shown in an embodiment of the present disclosure;
[0024] Figure 5 is a schematic diagram of the orthographic projection of the active region of yet another acoustic wave device shown in an embodiment of the present disclosure;
[0025] Figure 6 is a schematic diagram of the shape of a closed figure shown in an embodiment of the present disclosure;
[0026] Figure 7 is a top view schematic diagram of an acoustic wave device shown in the first embodiment of the present disclosure;
[0027] Figure 8 It is a schematic diagram of the test of an acoustic wave device shown in the first embodiment of the present disclosure;
[0028] Figure 9 It is a top view schematic diagram of an acoustic wave device shown in the second embodiment of the present disclosure;
[0029] Figure 10 It is a schematic diagram of the test of an acoustic wave device shown in the second embodiment of the present disclosure;
[0030] Figure 11 It is a top view schematic diagram of an acoustic wave device shown in the third embodiment of the present disclosure;
[0031] Figure 12 It is a schematic diagram of the test of an acoustic wave device shown in the third embodiment of the present disclosure;
[0032] Figure 13 It is a top view schematic diagram of an acoustic wave device shown in the fourth embodiment of the present disclosure;
[0033] Figure 14 It is a schematic diagram of the test of an acoustic wave device shown in the fourth embodiment of the present disclosure;
[0034] Figure 15 It is a flowchart of a manufacturing method of an acoustic wave device shown in the embodiments of the present disclosure. Detailed implementation manners
[0035] The technical solutions of the present disclosure will be further elaborated in detail below in conjunction with the accompanying drawings and embodiments. Although the exemplary implementation methods of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the implementation manners described herein. On the contrary, these implementation manners are provided to enable a more thorough understanding of the present disclosure and to be able to fully convey the scope of the present disclosure to those skilled in the art.
[0036] In the following paragraphs, the present disclosure will be described more specifically by way of example with reference to the accompanying drawings. According to the following description, the advantages and features of the present disclosure will be clearer. It should be noted that the drawings are all in a very simplified form and use non-precise scales, only for the purpose of facilitating and clearly assisting in explaining the purpose of the embodiments of the present disclosure.
[0037] It can be understood that the meanings of "on...", "above...", and "overhead of..." in the present disclosure should be interpreted in the broadest manner, so that "on..." not only means "on" something without any intervening features or layers (i.e., directly on something), but also includes the meaning of having intervening features or layers on something.
[0038] In the embodiments of the present disclosure, the terms "first", "second", "third", etc. are used to distinguish similar objects, and do not necessarily describe a specific order or sequence.
[0039] In the embodiments of the present disclosure, the term "layer" refers to a portion of a material that includes a region having a thickness. The layer may extend over the entirety of a structure below or above, or may have a scope smaller than the scope of the structure below or above. Additionally, the layer may be a region of a homogeneous or heterogeneous continuous structure with a thickness less than the thickness of the continuous structure. For example, the layer may be located between the top and bottom surfaces of the continuous structure, or the layer may be between any horizontal planes at the top and bottom surfaces of the continuous structure. The layer may extend horizontally, vertically, and / or along an inclined surface. The layer may include multiple sub-layers.
[0040] It should be noted that the technical solutions described in the embodiments of the present disclosure may be combined arbitrarily without conflict.
[0041] Figure 1A is a cross-sectional schematic diagram of an acoustic wave device shown in an exemplary embodiment, Figure 1B is a schematic diagram of acoustic waves generated within an acoustic wave device shown in an exemplary embodiment, Figure 1C is a schematic diagram of the orthographic projection of the active region of an acoustic wave device shown in an exemplary embodiment. In this example, the acoustic wave device includes, but is not limited to, a Film Bulk Acoustic Resonator (FBAR). For ease of understanding, the following will use the FBAR as an example to Figures 1A to 1C give an exemplary description.
[0042] Referring to Figure 1A and Figure 1B as shown, when electrical energy is applied to the upper electrode 130 and the lower electrode 110 of the FBAR, acoustic waves are generated in the piezoelectric layer 120 located in the upper electrode 130 and the lower electrode 110 due to the piezoelectric effect. In addition to longitudinal waves, transverse shear waves are also generated in the piezoelectric layer 120. The longitudinal waves and transverse shear waves generated in the piezoelectric layer 120 are as Figure 1B shown. The transverse shear waves will propagate laterally in the FBAR. When there are parallel sides at the edge of the active region 100a, the transverse shear waves will reflect back and forth between the parallel sides to form transverse standing waves, resulting in an impact on the performance of the resonator.
[0043] It should be noted that in this example, the region where the reflection structure (in this embodiment, the reflection structure is a cavity), the lower electrode 110, the piezoelectric layer 120, and the upper electrode 130 overlap can be defined as the active region 100a (also referred to as the "resonant region") of the acoustic wave device 100, and the region outside the active region 100a can be defined as the non-active region 100b (also referred to as the "non-resonant region") of the acoustic wave device 100. The active region 100a and the non-active region 100b are asFigure 1A As shown in the figure; wherein, the orthographic projection of the active region 100a is a closed figure.
[0044] In the above example, there are at least three cases where there are parallel sides at the edge of the active region 100a: 1) The closed figure has at least a pair of parallel contour edges; 2) A certain contour edge of the closed figure is parallel to the tangent line passing through the tangent points on other contour edges of the closed figure; 3) The tangent line passing through the tangent points on a certain contour edge of the closed figure is parallel to the tangent line passing through the tangent points on other contour edges of the closed figure. Exemplarily, Figure 1C It is shown that the contour edge S1 of the closed figure S is parallel to the tangent line L passing through the tangent point P on the contour edge S2, that is, the contour edge S1 is parallel to the tangent line L, and the transverse shear wave reflects back and forth between the contour edge S1 and the tangent line L (as shown by the arrows in Figure 1C ) to form a transverse standing wave, resulting in the performance of the resonator being affected.
[0045] Based on one or more of the above technical problems, an embodiment of the present disclosure provides an acoustic wave device. The acoustic wave device includes a reflection structure, a first electrode layer, a piezoelectric layer, and a second electrode layer stacked in sequence. The overlapping portions of the reflection structure, the first electrode layer, the piezoelectric layer, and the second electrode layer in the stacking direction form an active region; wherein, the orthographic projection of the active region is a closed figure, and an irregular structure is provided on the contour edge of the closed figure; the irregular structure makes the slopes of any two contour edges of the closed figure different, or the irregular structure makes the slope of the tangent line passing through the tangent point on any one contour edge of the closed figure different from the slopes of the other contour edges of the closed figure, or the irregular structure makes the slopes of the tangent lines passing through any tangent points on the contour edge of the closed figure different from the slopes of the tangent lines passing through other tangent points on the contour edge of the closed figure. In this way, by providing an irregular structure on the contour edge of the closed figure corresponding to the active region, the irregular structure can make any two contour edges of the closed figure not parallel (that is, the closed figure has no parallel sides), or make the tangent line passing through the tangent point on any one contour edge of the closed figure not parallel to the other contour edges of the closed figure, or make the tangent line passing through the tangent point on any one contour edge of the closed figure not parallel to the tangent line passing through other tangent points on the contour edge of the closed figure, that is, the irregular structure can make there be no parallel sides at the edge of the active region, so as to change the propagation direction of the transverse shear wave and suppress the formation of a standing wave due to the back-and-forth reflection of the transverse shear wave in the acoustic wave device, which is beneficial to improving the performance of the acoustic wave device.
[0046] Figure 2 It is a schematic diagram of the orthographic projection of the active region of an acoustic wave device shown in an embodiment of the present disclosure. The acoustic wave device includes a SAW device, a BAW device, an FBAR device, or other acoustic wave devices known in the art. The following will be combined with Figure 2 to give an exemplary description of the acoustic wave device provided by the embodiment of the present disclosure.
[0047] The acoustic wave device includes a reflection structure, a first electrode layer, a piezoelectric layer, and a second electrode layer stacked in sequence. The reflection structure, the first electrode layer, the piezoelectric layer, and the second electrode layer can be located on one side of the substrate. The material of the substrate includes elemental semiconductor materials (such as silicon, germanium), III-V compound semiconductor materials, II-VI compound semiconductor materials, organic semiconductor materials, or other semiconductor materials known in the art.
[0048] The first electrode layer can be referred to as the lower electrode or the bottom electrode, and the second electrode layer can be referred to as the upper electrode or the top electrode. Electrical energy can be applied to the acoustic wave device through the first electrode layer and the second electrode layer. The materials of the first electrode layer and the second electrode layer include at least one of aluminum (Al), molybdenum (Mo), ruthenium (Ru), chromium (Cr), iridium (Ir), or platinum (Pt). The materials of the first electrode layer and the second electrode layer can be the same or different. In one example, the materials of the first electrode layer and the second electrode layer are the same.
[0049] The piezoelectric layer can be used to generate vibrations according to the inverse piezoelectric effect, convert the electrical signal applied to the first electrode layer and the second electrode layer into an acoustic wave signal, and achieve the conversion of electrical energy into mechanical energy. The material of the piezoelectric layer can include materials with piezoelectric properties, such as aluminum nitride, zinc oxide, lithium tantalate, lead zirconate titanate, or barium titanate, etc. The material of the piezoelectric layer can also include materials with piezoelectric properties through doping. The doping can be transition metals, rare metals, or group V elements, etc., such as scandium-doped aluminum nitride, etc.
[0050] The reflection structure is used to reflect the acoustic wave signal. When the acoustic wave signal generated by the piezoelectric layer propagates towards the reflection structure, the acoustic wave signal can undergo total reflection at the interface where the first electrode layer and the reflection structure are in contact, so that the acoustic wave signal is reflected back into the piezoelectric layer. In one example, the reflection structure can be a cavity formed between the substrate and the first electrode layer. Of course, in other examples, the reflection structure can be a Bragg reflection structure.
[0051] It should be noted that in the embodiments of the present disclosure, the overlapping region of the reflection structure, the first electrode layer, the piezoelectric layer, and the second electrode layer can be defined as the active region of the acoustic wave device, that is, the overlapping part of the reflection structure, the first electrode layer, the piezoelectric layer, and the second electrode layer along the stacking direction constitutes the active region, and the region outside the active region is defined as the non-active region; wherein, the orthographic projection of the active region is a closed figure.
[0052] Irregular structures are provided on the contour edges of the closed figure; the irregular structures make the slopes of any two contour edges of the closed figure different, or the irregular structures make the tangent slope of the tangent point on any one contour edge of the closed figure different from the slopes of the other contour edges of the closed figure, or the irregular structures make the tangent slopes of any two tangent points on the contour edges of the closed figure different from each other.
[0053] In the embodiments of the present disclosure, a closed figure is formed by connecting at least one contour edge. By designing an irregular structure on at least one contour edge of the closed figure, that is, by arranging an irregular structure on at least one contour edge, it can be ensured that there are no parallel sides in the closed figure (that is, there are no parallel sides at the edge of the active region). That is, the irregular structure makes the slopes of any two contour edges of the closed figure different, or the irregular structure makes the slope of the tangent line at the tangent point on any one contour edge of the closed figure different from the slopes of the other contour edges of the closed figure, or the irregular structure makes the slopes of the tangent lines at any two tangent points on the contour edge of the closed figure different. Therefore, the irregular structure is arranged on at least one contour edge. In practical applications, the position of the irregular structure can be reasonably selected according to whether there are parallel sides on the contour edge of the closed figure. The present disclosure has no special limitation on this.
[0054] In one example, referring to Figure 2 As shown, the closed figure S includes a first contour edge S1 and a second contour edge S2. An irregular structure 201a is arranged on the first contour edge S1. The irregular structure 201a makes the slope of the first contour edge S1 different from the slope of the tangent line at the tangent point P1 on the second contour edge S2, that is, the first contour edge S1 is not parallel to the tangent line L1 passing through the tangent point P1. In this example, the closed figure S includes two contour edges (for example, the first contour edge S1 and the second contour edge S2), and the irregular structure 201a can be arranged on the first contour edge S1.
[0055] In another example, referring to Figure 2 As shown, an irregular structure 201b is arranged on the second contour edge S2. The irregular structure 201b makes the slope of the first contour edge S1 different from the slope of the tangent line at the tangent point on the second contour edge S2, that is, the first contour edge S1 is not parallel to the tangent line passing through the tangent point on the second contour edge S2. In this example, the closed figure S includes two contour edges (for example, the first contour edge S1 and the second contour edge S2), and the irregular structure 201b can be arranged on the second contour edge S2. It can be understood that when the irregular structure 201b is arranged on the second contour edge S2, the tangent point P1 no longer belongs to the second contour edge S2, that is, the tangent point P1 is disrupted.
[0056] It can be understood that Figure 2 In the example shown, in the case where the irregular structure 201a and the irregular structure 201b are not arranged (refer to Figure 1C), the first contour edge S1 is parallel to the tangent line L1, and the transverse shear wave reflects back and forth between the first contour edge S1 and the tangent line L1 to form a transverse standing wave, which affects the performance of the resonator. In this example, by setting the irregular structure 201a on the first contour edge S1 or setting the irregular structure 201b on the second contour edge S2, the first contour edge S1 can be made non-parallel to the tangent line passing through the tangent point on the second contour edge S2, thereby avoiding the formation of a transverse standing wave due to the back-and-forth reflection of the transverse shear wave between the first contour edge S1 and the tangent line L1.
[0057] Of course, the above two examples can be combined, that is, setting the irregular structure 201a on the first contour edge S1 and setting the irregular structure 201b on the second contour edge S2. It should be noted that any irregular structure that can make the slope of the tangent line at the tangent point on the second contour edge S2 of the closed figure S different from the slope of the first contour edge S1 of the closed figure S should be covered by the protection scope of the present disclosure.
[0058] In one example, referring to Figure 2 As shown, the closed figure further includes a third contour edge S3, and an irregular structure 201c is provided on the third contour edge S3. The irregular structure 201c makes the slope of the third contour edge S3 different from the slope of the tangent line at the tangent point P2 on the second contour edge S2, that is, the third contour edge S3 is not parallel to the tangent line L2 passing through the tangent point P2. In this example, the closed figure S includes three contour edges (for example, the first contour edge S1, the second contour edge S2, and the third contour edge S3), and the irregular structure 201c can be set on the third contour edge S3.
[0059] In another example, referring to Figure 2 As shown, an irregular structure 201d is provided on the second contour edge S2. The irregular structure 201d makes the slope of the third contour edge S3 different from the slope of the tangent line at the tangent point on the second contour edge S2, that is, the third contour edge S3 is not parallel to the tangent line passing through the tangent point on the second contour edge S2. In this example, the closed figure S includes three contour edges (for example, the first contour edge S1, the second contour edge S2, and the third contour edge S3), and the irregular structure 201d can be set on the second contour edge S2. It can be understood that in the case where the irregular structure 201d is provided on the second contour edge S2, the tangent point P2 no longer belongs to the second contour edge S2, that is, the tangent point P2 is disrupted.
[0060] It can be understood that Figure 2 In the example shown, in the case where the irregular structures 201c and 201d are not provided (refer to Figure 1C) The third contour edge S3 is parallel to the tangent line L2, and the transverse shear wave reflects back and forth between the third contour edge S3 and the tangent line L2 to form a transverse standing wave, which affects the performance of the resonator. In this example, by setting the irregular structure 201c on the third contour edge S3 or setting the irregular structure 201d on the second contour edge S2, the third contour edge S3 can be made non-parallel to the tangent line passing through the tangent point on the second contour edge S2, thereby avoiding the formation of a transverse standing wave due to the back-and-forth reflection of the transverse shear wave between the third contour edge S3 and the tangent line L2.
[0061] Of course, the above two examples can be combined, that is, setting the irregular structure 201c on the third contour edge S3 and setting the irregular structure 201d on the second contour edge S2. It should be noted that any irregular structure that can make the slope of the tangent line at the tangent point on the second contour edge S2 of the closed figure S different from the slope of the third contour edge S3 of the closed figure should be covered by the protection scope of the present disclosure.
[0062] It should be pointed out that the irregular structures 201a, 201b, 201c, and 201d in the above examples represent the irregular structures located on the contour edges of the closed figure S, and their compositions and / or shapes can be the same or different. The different reference numerals are only used to distinguish the differences in the positions of multiple irregular structures, and do not have to be used to describe a specific order or sequence.
[0063] In some embodiments, the number of irregular structures can be one or more. In practical applications, the position and number of irregular structures can be reasonably set according to the actual situation of the edge of the active region to ensure that there are no parallel edges on the contour edge of the closed figure, that is, there are no parallel edges on the edge of the active region.
[0064] In some embodiments, when the number of irregular structures is more than two, the multiple irregular structures have the same or different spacings. Preferably, the multiple irregular structures have different spacings.
[0065] In some embodiments, when the number of irregular structures is multiple, the shapes of the multiple irregular structures can be the same or different. Preferably, the shapes of the multiple irregular structures are different; or, the shapes of the multiple irregular structures are the same, but they have different sizes.
[0066] In some embodiments, the irregular structure includes at least one n-sided polygon, where n is an integer greater than 2. Preferably, the irregular structure includes three n-sided polygons arranged at intervals. In the embodiments of the present disclosure, by designing an irregular structure on the contour edge of a closed figure, the irregular structure is composed of at least one n-sided polygon, and the contour edge of the closed figure can be disrupted to form an irregular contour edge, so that there are no parallel sides in the closed figure, that is, there are no parallel sides at the edge of the active region.
[0067] In one example, referring to Figure 2 as shown, the irregular structure 201a includes a quadrilateral. In this example, the value of n is 4, and the number of n-sided polygons is one. In other examples, the value of n can also be 3 or other integers greater than 4.
[0068] In one example, referring to Figure 2 as shown, the irregular structure 201c includes a quadrilateral. In this example, the value of n is 4, and the number of n-sided polygons is one. In other examples, the value of n can also be 3 or other integers greater than 4.
[0069] In one example, referring to Figure 2 as shown, the irregular structure 201b includes three quadrilaterals arranged at intervals. In this example, the value of n is 4, and the number of n-sided polygons is three. In other examples, the value of n can also be 3 or other integers greater than 4.
[0070] In one example, referring to Figure 2 as shown, the irregular structure 201d includes three quadrilaterals arranged at intervals. In this example, the shape of the n-sided polygon in the irregular structure 201d is the same as that in the irregular structure 201b, both are quadrilaterals; the number of n-sided polygons in the irregular structure 201d is the same as that in the irregular structure 201b, both are three. However, in other examples, the shape and / or number of n-sided polygons in the irregular structure can be the same or different, and the shape of the n-sided polygon in the irregular structure will be described in detail below.
[0071] In some embodiments, the sides of the n-sided polygon include at least one of a straight side and a curved side. It can be understood that the shape of the n-sided polygon depends on the sides of the n-sided polygon, and the shape of the n-sided polygon will be exemplarily described below in conjunction with Figure 3
[0072] Figure 3 is a schematic diagram of the shape of an n-sided polygon shown in the embodiments of the present disclosure. Referring to Figure 3 as shown in Figure (a) therein, the sides of the n-sided polygon include three straight sides, and the three straight sides are sequentially connected end to end to form a triangle. Referring to Figure 3 As shown in Figure (b), the sides of the n-sided polygon include two straight sides and one curved side. Refer to Figure 3 As shown in Figure (c), the sides of the n-sided polygon include three curved sides. It should be noted that the shape of the n-sided polygon is not limited to Figure 3 as shown, and it can also be other regular shapes or irregular shapes.
[0073] In some embodiments, the slopes of any two sides of the n-sided polygon are different, or the tangent slope of the tangent point on any side of the n-sided polygon is different from the slopes of the other sides of the n-sided polygon, or the tangent slope of the tangent point on any side of the n-sided polygon is different from the tangent slopes of the tangent points on the other sides of the n-sided polygon.
[0074] In one example, the n-sided polygon includes multiple straight sides, and any two straight sides are not parallel, that is, the slopes of any two sides of the n-sided polygon are different.
[0075] In one example, the n-sided polygon includes at least one straight side and at least one curved side, and the tangent slope of the tangent point on any curved side is different from the slope of any straight side, that is, the tangent slope of the tangent point on any side of the n-sided polygon is different from the slopes of the other sides of the n-sided polygon. In this example, the tangent point can be any point on the curved side.
[0076] In one example, the n-sided polygon includes multiple curved sides, and the tangent slope of the tangent point on any curved side is different from the tangent slopes of the tangent points on the other curved sides, that is, the tangent slope of the tangent point on any side of the n-sided polygon is different from the tangent slopes of the tangent points on the other sides of the n-sided polygon. In this example, the tangent point can be any point on the curved side.
[0077] It can be understood that if there are mutually parallel sides in the n-sided polygon itself, unwanted mutually parallel sides will be introduced due to the setting of the irregular structure. In the embodiments of the present disclosure, by setting the slopes of any two sides of the n-sided polygon to be different, or the tangent slope of the tangent point on any side of the n-sided polygon to be different from the slopes of the other sides of the n-sided polygon, or the tangent slope of the tangent point on any side of the n-sided polygon to be different from the tangent slopes of the tangent points on the other sides of the n-sided polygon. In this way, it is possible to avoid introducing unwanted mutually parallel sides due to the setting of the irregular structure. In practical applications, the n-sided polygon preferably has a shape without mutually parallel sides. For example, the n-sided polygon can be a triangle, an irregular quadrilateral, or a pentagon, etc., so as to ensure that there are no mutually parallel sides in the n-sided polygon itself.
[0078] In some embodiments, the irregular structure includes: a depression facing the inside of the active part; and / or, a protrusion facing the outside of the active part.
[0079] In one example, the irregular structure includes a depression facing the inside of the active part. For example, Figure 2The irregular structures 201b and 201d shown therein both include depressions facing the inside of the active portion. Here, the orthographic projection of the depression facing the inside of the active portion is a quadrilateral, that is, the irregular structure includes at least one n-sided polygon arranged at intervals.
[0080] In one example, the irregular structure includes a protrusion facing the outside of the active portion. For example, Figure 2 the irregular structures 201a and 201c shown therein both include protrusions facing the outside of the active portion.
[0081] Of course, the above two examples can be combined, that is, the irregular structure includes a depression facing the inside of the active portion and a protrusion facing the outside of the active portion. It should be noted that the shape of the irregular structure mentioned in this solution is for a single irregular structure. When the irregular structure is arranged on the resonator to form a depression facing the inside of the active portion and a protrusion facing the outside of the active portion, it becomes a part of the resonator, and the projection shape is used as the judgment of the irregular structure shape. By designing depressions and / or protrusions on the contour edge of the closed figure, an irregular contour edge can be formed, so that there are no parallel edges at the edge of the active region.
[0082] Figure 4 is a schematic diagram of the orthographic projection of the active region of another acoustic wave device shown in an embodiment of the present disclosure. It should be noted that Figure 4 the same structures as those in the above embodiment are continued to use the same reference numerals, and the same structures can refer to the relevant descriptions of the above embodiment and will not be described in detail. This embodiment only details the different structures.
[0083] Referring to Figure 4 as shown, the closed figure S includes a first contour edge S1, and an irregular structure 201 is provided on the first contour edge S1. The irregular structure 201 makes the tangent slope of the tangent point on the first contour edge S1 different from the tangent slope of the tangent point P2, that is, the tangent passing through a certain tangent point on the first contour edge S1 is not parallel to the tangent line L2 passing through the tangent point P2. In this example, the closed figure S includes a contour edge (for example, the first contour edge S1), and the irregular structure 201 can be provided on the first contour edge S1. It can be understood that by providing the irregular structure 201 on the first contour edge S1, the tangent point P1 no longer belongs to the first contour edge S1, that is, the tangent point P1 is disrupted to form an irregular first contour edge S1. Of course, in other embodiments, the irregular structure can also be provided at the tangent point P2 of the first contour edge S1. At this time, the tangent point P2 no longer belongs to the first contour edge S1, that is, the tangent point P2 is disrupted to form an irregular first contour edge S1.
[0084] Figure 5 is a schematic diagram of the orthographic projection of the active region of yet another acoustic wave device shown in an embodiment of the present disclosure. It should be noted that Figure 5For the embodiments shown below, the same structures as those in the above embodiments continue to be denoted by the same reference numerals, and for the same structures, reference may be made to the relevant descriptions of the above embodiments and will not be described in detail herein. Only the different structures will be described in detail in this embodiment.
[0085] Referring to Figure 5 as shown, the closed figure S includes a first contour edge S1, on which there is an irregular structure 201. The irregular structure 201 includes three n-sided polygons, which are a quadrilateral, a triangle, and a quadrilateral respectively, that is, the shapes of any two n-sided polygons within the irregular structure 201 may be the same or different. It should be noted that the shapes and numbers of the n-sided polygons within the irregular structure 201 are not limited to Figure 5 as shown, and other shapes and numbers may also be possible.
[0086] In some embodiments, the contour edge of the closed figure includes at least one of a straight edge and a curved edge. It can be understood that the shape of the closed figure depends on the shape and number of the contour edges. Below, an exemplary description of the shape of the closed figure will be given in conjunction with Figure 6 For the sake of easy understanding, the curved edges are represented as arcs in Figure 6 , however, the curved edges can also be other curves.
[0087] Figure 6 is a schematic diagram of the shape of the closed figure shown in the embodiments of the present disclosure. Figure 6 The black dots in Figure 6 represent the intersections of straight edges and straight edges, the intersections of straight edges and arcs, or the intersections of arcs and arcs. Referring to Figure 6 as shown, the contour edge of the closed figure includes at least one straight edge and / or at least one arc. For example, the contour edge of the closed figure is composed of one arc or multiple arcs, that is, the contour edge of the closed figure has no straight edges. Another example is that the contour edge of the closed figure is composed of one straight edge and at least one arc. Still another example is that the contour edge of the closed figure is composed of two straight edges and at least one arc. Yet another example is that the contour edge of the closed figure is composed of three straight edges and at least one arc. It should be noted that the shape of the closed figure is not limited to Figure 6 as shown, and other shapes are also possible.
[0088] Figure 7 is a top view schematic diagram of an acoustic wave device shown in the first embodiment of the present disclosure. Referring to Figure 7 as shown, the acoustic wave device includes a reflection structure 210, a first electrode layer 220, and a second electrode layer 230 stacked in sequence. On the arc contour edge of the second electrode layer 230, there are an irregular structure 201b and an irregular structure 201d. Both the irregular structure 201b and the irregular structure 201d include three quadrilaterals. For the irregular structure 201b and the irregular structure 201d, reference may be made to Figure 2The related description. By setting the irregular structures 201b and 201d on the arc-shaped contour edge of the second electrode layer 230, it can be ensured that the tangent line passing through the tangent point on the arc-shaped contour edge of the second electrode layer 230 and the straight-line contour edge of the second electrode layer 230 do not have parallel sides. The following will be combined with Figure 8 For Figure 1C the two acoustic wave devices without the irregular structure and Figure 7 the test results of the two acoustic wave devices with the irregular structures 201b and 201d set in
[0089] Figure 8 is a test schematic diagram of an acoustic wave device shown in the first embodiment of the present disclosure. Among them, Figure 8 Figure (a) in Figure 8 is the impedance-frequency curve graph of the two acoustic wave devices without the irregular structure and with the irregular structure set, Figure 8 Figure (b) in Figure 8 is the Smith chart of the two acoustic wave devices without the irregular structure and with the irregular structure set,
[0090] Referring to Figure 8 as shown in Figure (a) in Figure 8 the impedance (Zp) corresponding to the acoustic wave device with the irregular structure set at the parallel resonance frequency (fp) is greater than the impedance corresponding to the acoustic wave device without the irregular structure set at the parallel resonance frequency; referring to Figure 8 as shown in Figure (b) in Figure 8 the Smith chart corresponding to the acoustic wave device with the irregular structure set is larger than the Smith chart corresponding to the acoustic wave device without the irregular structure set; referring to Figure 8 as shown in Figure (c) in Figure 7 the modal vibration mode graph of the acoustic wave device without the irregular structure set is mainly the longitudinal wave mode, but still contains many oscillating small waves, which are caused by the coupling of the transverse shear wave mode and the longitudinal wave mode. Referring to Figure 1C as shown in Figure (d) in
[0091] Table 1 Figure 1C the two acoustic wave devices without the irregular structure and Figure 7 the performance parameters of the two acoustic wave devices with the irregular structure set in
[0092]
[0093] As can be seen from Table 1, Figure 7 the fs, fp, kt2 of the acoustic wave device with an irregular structure set therein and Figure 1C the fs, fp, kt2 of the acoustic wave device without an irregular structure set therein are the same, Figure 7 the Qs and Qp of the acoustic wave device with an irregular structure set therein are Figure 1C greater than the Qs and Qp of the acoustic wave device without an irregular structure set therein. That is, setting the irregular structure is beneficial to increasing the quality factor Q of the acoustic wave device and does not affect the series resonance frequency, parallel resonance frequency, and effective electromechanical coupling coefficient of the acoustic wave device.
[0094] Figure 9 is a top view schematic diagram of an acoustic wave device shown in the second embodiment of the present disclosure. Referring to Figure 9 as shown, the acoustic wave device includes a reflection structure 210, a first electrode layer 220, and a second electrode layer 230 stacked in sequence. Irregular structures 201b' and 201d' are provided on the arc-shaped contour edge of the second electrode layer 230. Different from Figure 7 is that Figure 9 both the irregular structure 201b' and the irregular structure 201d' in Figure 10 include three triangles (for example, triangles). The test results of the two acoustic wave devices without an irregular structure set therein and Figure 1C with the irregular structures 201b' and 201d' set therein in Figure 9 will be exemplarily described below.
[0095] Figure 10 is a test schematic diagram of an acoustic wave device shown in the second embodiment of the present disclosure. Among them, Figure 10 in figure (a) of Figure 10 is the impedance-frequency curve diagram of the two acoustic wave devices without an irregular structure set therein and with an irregular structure set therein, Figure 10 in figure (b) of Figure 10 is the Smith chart of the two acoustic wave devices without an irregular structure set therein and with an irregular structure set therein,
[0096] Referring to Figure 10 as shown in figure (a) of Figure 10As shown in Figure (b), the Smith circle corresponding to the acoustic wave device with an irregular structure is larger than that corresponding to the acoustic wave device without an irregular structure; referring to Figure 10 As shown in Figure (c), the modal vibration mode diagram of the acoustic wave device without an irregular structure is mainly the longitudinal wave mode, but still contains many oscillating small waves, which are caused by the coupling of the transverse shear wave mode and the longitudinal wave mode. Referring to Figure 10 As shown in Figure (d), the vibration mode diagram of the acoustic wave device with an irregular structure is the longitudinal wave mode, and there are basically no oscillating small waves. Therefore, Figure 10 The test results in Figure 9 all show that the performance of the acoustic wave device with the irregular structures 201b’ and 201d’ set in Figure 1C is better than that of the acoustic wave device without an irregular structure in
[0097] Table 2 Figure 1C The performance parameters of the two acoustic wave devices without an irregular structure set in Figure 9 and with an irregular structure set in
[0098]
[0099]
[0100] As can be seen from Table 2, Figure 9 the fs, fp of the acoustic wave device with an irregular structure set in Figure 1C and the fs, fp of the acoustic wave device without an irregular structure set in Figure 9 are basically the same. The kt2, Qs, Qp of the acoustic wave device with an irregular structure set in Figure 1C are larger than those of the acoustic wave device without an irregular structure set in Figure 9 That is, setting an irregular structure is beneficial to increasing the quality factor of the acoustic wave device and does not affect the series resonance frequency and parallel resonance frequency of the acoustic wave device. In addition,
[0101] Figure 11 is a top view schematic diagram of an acoustic wave device shown in the third embodiment of the present disclosure. Referring to Figure 11 As shown, the acoustic wave device includes a reflection structure 210, a first electrode layer 220, and a second electrode layer 230 stacked in sequence. Irregular structures are provided on each contour edge of the second electrode layer 230, which are respectively represented as irregular structures 201a, 201b, 201c (as Figure 11as shown by the dashed-line frame), the irregular structures on each contour edge each include a plurality of quadrilaterals, and the number of quadrilaterals can be reasonably set according to the side length of the corresponding contour edge. Below, an exemplary description will be given of the test results of two acoustic wave devices, one without an irregular structure in Figure 12 and Figure 1C one with irregular structures 201a, 201b, and 201c set therein in Figure 11
[0102] Figure 12 FIG. is a test schematic diagram of an acoustic wave device shown in the third embodiment of the present disclosure. Among them, Figure 12 in FIG. (a) is the modal vibration mode diagram of the acoustic wave device without an irregular structure, Figure 12 and in FIG. (b) is the modal vibration mode diagram of the acoustic wave device with an irregular structure.
[0103] Referring to Figure 12 as shown in FIG. (a) therein, the modal vibration mode diagram of the acoustic wave device without an irregular structure is mainly a longitudinal wave mode, but still contains many oscillating small waves, which are caused by the coupling of the transverse shear wave mode and the longitudinal wave mode. Referring to Figure 12 as shown in FIG. (b) therein, the vibration mode diagram of the acoustic wave device with an irregular structure is a longitudinal wave mode and basically has no oscillating small waves. Therefore, Figure 12 the test results in Figure 11 show that the performance of the acoustic wave device with irregular structures provided on each contour edge in Figure 1C is superior to that of the acoustic wave device without an irregular structure in
[0104] Figure 13 FIG. is a top view schematic diagram of an acoustic wave device shown in the fourth embodiment of the present disclosure. Referring to Figure 13 as shown, the acoustic wave device includes a reflection structure 210, a first electrode layer 220, and a second electrode layer 230 stacked in sequence. Irregular structures are provided on each contour edge of the second electrode layer 230, which are respectively denoted as irregular structures 201a', 201b', and 201c' (as Figure 13 shown by the dashed-line frame). The irregular structures on each contour edge each include a plurality of triangles, and the number of triangles can be reasonably set according to the side length of the corresponding contour edge. Below, an exemplary description will be given of the test results of two acoustic wave devices, one without an irregular structure in Figure 14 and Figure 1C one with irregular structures 201a', 201b', and 201c' set therein in Figure 13
[0105] Figure 14 FIG. is a test schematic diagram of an acoustic wave device shown in the fourth embodiment of the present disclosure. Among them, Figure 14In Figure (a), the modal vibration mode diagram of the acoustic wave device without the irregular structure is shown, Figure 14 and in Figure (b), the modal vibration mode diagram of the acoustic wave device with the irregular structure is shown.
[0106] Referring to Figure 14 Figure (a) as shown, the modal vibration mode diagram of the acoustic wave device without the irregular structure is mainly the longitudinal wave mode, but still contains many oscillating small waves, which are caused by the coupling of the transverse shear wave mode and the longitudinal wave mode. Referring to Figure 14 Figure (b) as shown, the vibration mode diagram of the acoustic wave device with the irregular structure is the longitudinal wave mode, and basically there are no oscillating small waves. Therefore, Figure 14 the test results in Figure 13 show that the performance of the acoustic wave device with irregular structures provided on each contour edge in Figure 1C is better than that of the acoustic wave device without the irregular structure in
[0107] In some embodiments, the sum of the side length of the n-sided polygon and the distance between adjacent n-sided polygons is less than 1 / 5 of the side length of the contour edge where the irregular structure is located. Exemplarily, referring to Figure 7 and Figure 9 as shown, the sum of b1 and a1 is less than 1 / 5 of the side length of the arc contour edge of the second electrode layer 230. b1 represents the side length of the n-sided polygon, and a1 represents the distance between adjacent n-sided polygons.
[0108] In some embodiments, the sum of the side length of the n-sided polygon and the distance between adjacent n-sided polygons is greater than 4 μm. Exemplarily, referring to Figure 7 and Figure 9 as shown, the sum of b1 and a1 is greater than 4 μm.
[0109] It should be noted that if the side length b1 of the n-sided polygon and the distance a1 between adjacent n-sided polygons are relatively large, it will change the area of the acoustic wave device, affecting the subsequent layout of the resonator on a wafer. For example, it expands the occupied area of the acoustic wave device and reduces the usable area of the wafer, and there may also be unwanted parallel sides due to the overly long side length b1 of the n-sided polygon. In the embodiments of the present disclosure, by setting the irregular structure and controlling the sum of the side length of the n-sided polygon and the distance between adjacent n-sided polygons to be greater than 4 μm and less than 1 / 5 of the side length of the contour edge where the irregular structure is located, the layout can be optimized and unwanted parallel sides can be avoided.
[0110] In some embodiments, an irregular structure is provided on the contour edge of at least one of the reflection structure, the first electrode layer, the piezoelectric layer, and the second electrode layer, so as to disrupt the contour edge of at least one of the reflection structure, the first electrode layer, the piezoelectric layer, and the second electrode layer to form an irregular contour edge. It should be noted that although Figure 7 , Figure 9 ,Figure 11 , Figure 13 shows an irregular structure provided on the contour edge of the second electrode layer 230. However, the present disclosure is not limited thereto, and an irregular structure may also be provided on Figure 7 , Figure 9 , Figure 11 , Figure 13 the contour edge of at least one of the shown reflection structure, the first electrode layer, and the piezoelectric layer.
[0111] In some embodiments, the irregular structure further includes a frame structure, a cantilever structure, or a bridge structure provided on at least a part of the edge of the second electrode layer. For example, a frame structure, a cantilever structure, or a bridge structure may be formed at the position of the edge of the second electrode layer.
[0112] Based on the above acoustic wave device, an embodiment of the present disclosure provides a method for manufacturing an acoustic wave device, and this manufacturing method can be used to manufacture the acoustic wave device in any of the above embodiments.
[0113] Figure 15 is a flowchart of a method for manufacturing an acoustic wave device shown in an embodiment of the present disclosure. It should be noted that Figure 15 the steps shown in are not exclusive, and other steps may also be performed before, after, or between any of the shown operations; Figure 15 the steps shown in can be adjusted in order according to actual needs. Referring to Figure 15 shown, this manufacturing method includes the following steps:
[0114] S310: Form a sequentially stacked reflection structure, first electrode layer, piezoelectric layer, and second electrode layer, wherein the overlapping portions of the reflection structure, first electrode layer, piezoelectric layer, and second electrode layer in the stacking direction constitute an active region;
[0115] S320: Form an irregular structure at the edge of the active region, wherein the orthographic projection of the active region is a closed figure, and the irregular structure is formed on the contour edge of the closed figure; the irregular structure makes the slopes of any two contour edges of the closed figure different, or the irregular structure makes the tangent slope of the tangent point on any one contour edge of the closed figure different from the slopes of the other contour edges of the closed figure, or the irregular structure makes the tangent slopes of any two tangent points on the contour edge of the closed figure different from each other.
[0116] In step S310, a sequentially stacked reflection structure, first electrode layer, piezoelectric layer, and second electrode layer may be formed on one side of the substrate. The formation processes of the reflection structure, first electrode layer, piezoelectric layer, and second electrode layer include thin film deposition processes, photolithography processes, and etching processes. Regarding the materials of the substrate, reflection structure, first electrode layer, piezoelectric layer, and second electrode layer, reference may be made to the relevant descriptions in the foregoing embodiments.
[0117] In step S320, at least one contour edge of the active region can be etched to form an irregular structure at the edge of the active region. The contour edge of the active region includes the contour edge of at least one of a reflective structure, a first electrode layer, a piezoelectric layer, and a second electrode layer. For the irregular structure, reference can be made to Figures 2 to 14 the relevant description of
[0118] In the embodiments of the present disclosure, by forming an irregular structure at the edge of the active region, any two contour edges of the closed figure can be made non-parallel (that is, there are no parallel edges in the closed figure), or the tangent passing through the tangent point on any one contour edge of the closed figure is made non-parallel to the other contour edges of the closed figure, or the tangent passing through the tangent point on any one contour edge of the closed figure is made non-parallel to the tangent passing through the tangent points on the other contour edges of the closed figure. That is, the irregular structure can make there be no parallel edges at the edge of the active region, thereby changing the propagation direction of the transverse shear wave and suppressing the formation of standing waves due to the back-and-forth reflection of the transverse shear wave in the acoustic wave device, which is beneficial to improving the performance of the acoustic wave device.
[0119] As described above, the above are only the specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present disclosure can easily think of changes or substitutions, which should all be covered within the protection scope of the present disclosure.
Claims
1. An acoustic wave device, characterized in that, The acoustic wave device includes a reflection structure, a first electrode layer, a piezoelectric layer, and a second electrode layer stacked in sequence. The overlapping portions of the reflection structure, the first electrode layer, the piezoelectric layer, and the second electrode layer in the stacking direction form an active region; Wherein, the orthographic projection of the active region is a closed figure, and irregular structures are provided on the contour edges of the closed figure; the irregular structures make the slopes of any two of the contour edges of the closed figure different, or the irregular structures make the tangent slope of the tangent point on any one of the contour edges of the closed figure different from the slopes of the other contour edges of the closed figure, or the irregular structures make the tangent slopes of any two tangent points on the contour edges of the closed figure different from each other.
2. The acoustic wave device according to claim 1, characterized in that, The closed figure is formed by connecting at least one of the contour edges, and wherein the irregular structures are provided on at least one of the contour edges.
3. The acoustic wave device according to claim 2, characterized in that, The contour edges of the closed figure include at least one of straight edges and curved edges.
4. The acoustic wave device according to claim 1, characterized in that, The irregular structure includes at least one n-sided polygon, where n is an integer greater than 2.
5. The acoustic wave device according to claim 4, wherein The slopes of any two sides of the n-sided polygon are different, or the tangent slope of the tangent point on any one side of the n-sided polygon is different from the slopes of the other sides of the n-sided polygon, or the tangent slopes of the tangent points on any one side of the n-sided polygon are different from the tangent slopes of the tangent points on the other sides of the n-sided polygon.
6. The acoustic wave device according to claim 4 or 5, characterized in that, The sides of the n-sided polygon include at least one of straight edges and curved edges.
7. The acoustic wave device according to claim 4, characterized in that, The sum of the side length of the n-sided polygon and the distance between adjacent n-sided polygons is less than 1 / 5 of the side length of the contour edge where the irregular structure is located.
8. The acoustic wave device according to claim 4, wherein The sum of the side length of the n-sided polygon and the distance between adjacent n-sided polygons is greater than 4 μm.
9. The acoustic wave device according to claim 1, wherein The irregular structure includes: a depression facing the inside of the active part; and / or, a protrusion facing the outside of the active part.
10. The acoustic wave device according to claim 1, characterized in that, The irregular structure is provided on the contour edge of at least one of the reflection structure, the first electrode layer, the piezoelectric layer, and the second electrode layer.
11. The acoustic device according to claim 1, characterized in that, The irregular structure further includes a frame structure, a cantilever structure, or a bridge structure provided on at least a part of the edge of the second electrode layer.
12. A manufacturing method of an acoustic wave device, characterized in that, Including: Forming a reflection structure, a first electrode layer, a piezoelectric layer, and a second electrode layer stacked in sequence, wherein the overlapping portions of the reflection structure, the first electrode layer, the piezoelectric layer, and the second electrode layer in the stacking direction form an active region; Forming an irregular structure on the edge of the active region, wherein the orthographic projection of the active region is a closed figure, and the irregular structure is formed on the contour edge of the closed figure; the irregular structure makes the slopes of any two of the contour edges of the closed figure different, or the irregular structure makes the tangent slope of the tangent point on any one of the contour edges of the closed figure different from the slopes of the other contour edges of the closed figure, or the irregular structure makes the tangent slopes of any two tangent points on the contour edges of the closed figure different from each other.