CN118138001A - A surface acoustic wave device and filter - Google Patents
A surface acoustic wave device and filter Download PDFInfo
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- CN118138001A CN118138001A CN202410311403.1A CN202410311403A CN118138001A CN 118138001 A CN118138001 A CN 118138001A CN 202410311403 A CN202410311403 A CN 202410311403A CN 118138001 A CN118138001 A CN 118138001A
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
- H03H9/02—Details
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02543—Characteristics of substrate, e.g. cutting angles
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
- H03H9/02—Details
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02637—Details concerning reflective or coupling arrays
- H03H9/02685—Grating lines having particular arrangements
- H03H9/02724—Comb like grating lines
- H03H9/02732—Bilateral comb like grating lines
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
- H03H9/25—Constructional features of resonators using surface acoustic waves
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
- H03H9/46—Filters
- H03H9/64—Filters using surface acoustic waves
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- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Abstract
本申请涉及滤波器领域，公开了一种声表面波器件和滤波器，包括：衬底；位于所述衬底上的压电层；位于所述压电层上的叉指电极，所述叉指电极的垂直方向与声表面波器件的表面波传播方向存在大于零的夹角。本申请中声表面波器件包括衬底、压电层和叉指电极，其中，叉指电极的垂直方向与表面波传播方向之间具有大于零的夹角，即叉指电极为倾斜设置的，有利于减少表面波的寄生，即减少声表面波器件阻抗或者导纳曲线上的寄生，同时也可以降低声表面波器件构成的滤波器通带内的纹波、提升滤波器的带外抑制度。
The present application relates to the field of filters, and discloses a surface acoustic wave device and a filter, comprising: a substrate; a piezoelectric layer located on the substrate; and interdigital electrodes located on the piezoelectric layer, wherein the vertical direction of the interdigital electrodes and the surface wave propagation direction of the surface acoustic wave device have an angle greater than zero. In the present application, the surface acoustic wave device comprises a substrate, a piezoelectric layer, and interdigital electrodes, wherein the vertical direction of the interdigital electrodes and the surface wave propagation direction have an angle greater than zero, that is, the interdigital electrodes are arranged obliquely, which is conducive to reducing the parasitics of the surface wave, that is, reducing the parasitics on the impedance or admittance curve of the surface acoustic wave device, and at the same time, it can also reduce the ripple in the passband of the filter formed by the surface acoustic wave device and improve the out-of-band suppression of the filter.
Description
Technical Field
The present application relates to the field of filters, and more particularly, to a surface acoustic wave device and a filter.
Background
The surface acoustic wave filter (surface acoustic wave) is simply called a SAW filter, and the surface acoustic wave is an elastic wave which is generated and propagated on the surface of a piezoelectric substrate material and whose amplitude decreases rapidly with increasing depth into the substrate material.
The basic structure of the surface acoustic wave device comprises a substrate, a piezoelectric material layer with piezoelectric property and an interdigital electrode, wherein the piezoelectric material layer is positioned on the surface of the substrate, and the interdigital electrode is positioned on the piezoelectric material layer, and the vertical direction of the interdigital electrode is parallel to the propagation direction of the surface acoustic wave. The traditional arrangement mode of the interdigital electrodes causes serious surface wave parasitic, and meanwhile, the ripple wave in the passband of the filter formed by the surface acoustic wave device is high, and the out-of-band suppression degree of the filter is lower.
Therefore, how to solve the above technical problems should be of great interest to those skilled in the art.
Disclosure of Invention
The application aims to provide a surface acoustic wave device and a filter, which are used for reducing the parasitism of surface waves, reducing ripples in the passband of the filter and improving the out-of-band suppression degree of the filter.
In order to solve the above technical problems, the present application provides a surface acoustic wave device, comprising:
A substrate;
a piezoelectric layer on the substrate;
and the interdigital electrode is positioned on the piezoelectric layer, and an included angle larger than zero exists between the vertical direction of the interdigital electrode and the surface wave propagation direction of the surface acoustic wave device.
Optionally, the electrode units in the interdigital electrode are electrode units with equal thickness.
Optionally, the method further comprises:
The electrode heightening body is positioned on the electrode units at the two outermost sides.
Optionally, the length of the electrode heightening body is equal to the length of the electrode unit.
Optionally, the length of the electrode heightening body is smaller than the length of the electrode unit.
Optionally, the included angle ranges from 1 ° to 90 °.
Optionally, the method further comprises:
and the wide end structure body is positioned on the side surface of the electrode unit in the interdigital electrode and is connected with the electrode unit, and the width of the wide end structure body is larger than that of the electrode unit.
Optionally, the wide end structures are located on one side and/or both sides of the electrode unit.
Optionally, the method further comprises:
And the reflecting grating is positioned on one side or two sides of the interdigital electrode, and the reflecting grating is parallel to the interdigital electrode.
Optionally, the method further comprises:
An acoustic impedance layer located between the substrate and the piezoelectric layer.
Optionally, the acoustic impedance layer includes a first acoustic impedance unit layer and/or a second acoustic impedance unit layer; the acoustic impedance of the first acoustic impedance unit layer is larger than that of the second acoustic impedance unit layer, and the acoustic impedance of the second acoustic impedance unit layer is smaller than that of the piezoelectric layer.
Optionally, when the acoustic impedance layer includes a first acoustic impedance unit layer and a second acoustic impedance unit layer, the thickness of the first acoustic impedance unit layer is one fourth of a transverse wavelength or one fourth of a longitudinal wavelength in the first acoustic impedance unit layer, and the thickness of the second acoustic impedance unit layer is one fourth of a transverse wavelength or one fourth of a longitudinal wavelength in the second acoustic impedance unit layer.
Optionally, when the acoustic impedance layer includes a first acoustic impedance unit layer and a second acoustic impedance unit layer, a weight range of the first acoustic impedance unit layer for reflecting the transverse wave and the longitudinal wave in the first acoustic impedance unit layer is 0.1-10, and a weight range of the second acoustic impedance unit layer for reflecting the transverse wave and the longitudinal wave in the second acoustic impedance unit layer is 0.1-10.
Alternatively, when the acoustic impedance layer includes a first acoustic impedance unit layer and a second acoustic impedance unit layer, thicknesses of the first acoustic impedance unit layer and the second acoustic impedance unit layer gradually increase or gradually decrease in a direction away from the substrate.
The application also provides a filter comprising any one of the above surface acoustic wave devices.
The surface acoustic wave device provided by the application comprises: a substrate; a piezoelectric layer on the substrate; and the interdigital electrode is positioned on the piezoelectric layer, and an included angle larger than zero exists between the vertical direction of the interdigital electrode and the surface wave propagation direction of the surface acoustic wave device.
It can be seen that the surface acoustic wave device in the application comprises a substrate, a piezoelectric layer and an interdigital electrode, wherein an included angle larger than zero is formed between the vertical direction of the interdigital electrode and the propagation direction of the surface acoustic wave, namely, the interdigital electrode is obliquely arranged, the propagation direction of the sound wave in the interdigital electrode and the energy propagation direction of the surface acoustic wave device have a certain included angle, and the energy of the wave in a parasitic mode received by the interdigital electrode is reduced, even not received, thereby being beneficial to reducing the parasitic of the surface acoustic wave, namely, reducing the impedance of the surface acoustic wave device or the parasitic on an admittance curve, and simultaneously reducing the ripple wave in the passband of the filter formed by the surface acoustic wave device and improving the out-of-band suppression degree of the filter.
In addition, the application also provides a filter with the advantages.
Drawings
For a clearer description of embodiments of the application or of the prior art, the drawings that are used in the description of the embodiments or of the prior art will be briefly described, it being apparent that the drawings in the description below are only some embodiments of the application, and that other drawings can be obtained from them without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of an interdigital electrode in the prior art;
fig. 2 is a schematic structural diagram of an interdigital electrode according to an embodiment of the present application;
FIGS. 3 and 4 are schematic cross-sectional views of different SAW devices provided in an embodiment of the present application;
fig. 5 to 11 are schematic structural views of different interdigital electrodes according to an embodiment of the present application;
fig. 12 to 17 are schematic cross-sectional views of different surface acoustic wave devices according to embodiments of the present application;
Fig. 18 is a graph showing impedance contrast between a surface acoustic wave device according to an embodiment of the present application and a surface acoustic wave device according to a conventional technique;
fig. 19 is a graph showing the Q value comparison between a surface acoustic wave device according to an embodiment of the present application and a surface acoustic wave device according to a conventional technique;
FIG. 20 is a graph showing the impedance contrast of another SAW device in an embodiment of the present application with a SAW device in the conventional art;
Fig. 21 is a graph showing the Q value comparison between another surface acoustic wave device according to an embodiment of the present application and a conventional surface acoustic wave device;
In the figure: 1. interdigital electrodes 2, a substrate 3, a piezoelectric layer 4, an electrode heightening body 5, a wide end structure body 6, a reflecting grating 7, an acoustic impedance layer 11, electrode units 12, bus bars 71, a first acoustic impedance unit layer 72 and a second acoustic impedance unit layer.
Detailed Description
In order to better understand the aspects of the present application, the present application will be described in further detail with reference to the accompanying drawings and detailed description. It will be apparent that the described embodiments are only some, but not all, embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways other than those described herein, and persons skilled in the art will readily appreciate that the present invention is not limited to the specific embodiments disclosed below.
As described in the background section, as shown in fig. 1, in the current surface acoustic wave device, the vertical direction a of the interdigital electrode is parallel to the direction of the surface wave propagation B, and this arrangement of the interdigital electrode causes serious surface wave parasitic, and at the same time, the ripple wave in the passband of the filter formed by the surface acoustic wave device is high, and the out-of-band suppression degree of the filter is relatively low.
In view of this, the present application provides a surface acoustic wave device, please refer to fig. 2 to 6, comprising:
A substrate 2;
a piezoelectric layer 3 on the substrate 2;
And the interdigital electrode 1 is positioned on the piezoelectric layer 3, and an included angle alpha larger than zero exists between the vertical direction A of the interdigital electrode 1 and the surface wave propagation direction B of the surface acoustic wave device.
The interdigital electrode 1 includes a bus bar 12 and a plurality of electrode units 11, the electrode units 11 are distributed in a comb-tooth shape, and the bus bar 12 is connected with the end portions of the electrode units 11.
The material of the substrate 2 includes, but is not limited to, silicon carbide.
The material of the piezoelectric layer 3 includes, but is not limited to, any one or any combination of lithium tantalate, lithium niobate, aluminum nitride, scandium-doped aluminum nitride, zinc oxide, and piezoelectric ceramics.
The material of the interdigital electrode 1 includes any one or any combination of aluminum, tungsten, molybdenum, gold, copper, and silver.
The angle α between the vertical direction a of the interdigital electrode 1 and the surface wave propagation direction B of the surface acoustic wave device is referred to as the fluence angle.
The interdigital electrodes 1 are arranged in pairs, and the number of interdigital electrodes 1 is not limited in the present application, as the case may be.
In the present application, the angle α between the vertical direction a of the interdigital electrode 1 and the surface wave propagation direction B of the surface acoustic wave device is not limited, depending on the situation. As an embodiment, the included angle α may range from 1 ° to 90 °, for example, the included angle α may be 1 °, 10 °, 20 °, 40 °, 60 °, 80 °, 90 °, or the like.
As an embodiment, the electrode units 11 in the interdigital electrode 1 are electrode units 11 with equal thickness, as shown in fig. 3.
Referring to fig. 4 to 6, in other embodiments, the surface acoustic wave device may further include:
an electrode heightening body 4, wherein the electrode heightening body 4 is positioned on the electrode units 11 at the two outermost sides.
The material of the electrode heightening body 4 can be the same as that of the interdigital electrode 1, or can be different from that of the interdigital electrode 1, and the electrode heightening body is within the protection scope of the application.
The interdigital electrode 1 provided with the electrode heightening body 4 is positioned at two outermost sides of the transverse transmission direction of the surface wave, and the thickness of the interdigital electrode 1 provided with the electrode heightening body 4 is larger than that of other interdigital electrodes 1, so that transverse leakage of the surface wave can be reduced, and the performance of the surface acoustic wave device, such as the Q value of the surface acoustic wave resonator, the insertion loss and the squareness of the surface acoustic wave filter, can be improved.
As shown in fig. 4 and 5, as an embodiment, the length of the electrode elevation body 4 is equal to the length of the electrode unit 11.
The width of the electrode raised body 4 may be equal to the width of the interdigital electrode 1.
As another embodiment, as shown in fig. 6, the length of the electrode heightening body 4 is smaller than the length of the electrode unit 11.
It should be noted that the specific length value of the electrode heightening body 4 can be set according to the need, and the application is not limited thereto. The further electrode raised bodies 4 may be disposed on the interdigital electrodes 1 by themselves, for example, the electrode raised bodies 4 may be disposed in regions corresponding to and overlapping the interdigital electrodes 1, as shown in fig. 6, or may be disposed in regions not corresponding to and overlapping the interdigital electrodes 1, or in regions corresponding to and overlapping the interdigital electrodes 1.
In this embodiment, the surface acoustic wave device includes a substrate 2, a piezoelectric layer 3 and an interdigital electrode 1, where an included angle α greater than zero is formed between a vertical direction a of the interdigital electrode 1 and a surface acoustic wave propagation direction B, that is, the interdigital electrode 1 is obliquely disposed, and the propagation direction of the acoustic wave in the interdigital electrode 1 and the energy propagation direction of the surface acoustic wave device have a certain included angle, so that the energy of the wave received by the interdigital electrode 1 in a parasitic mode is reduced, or even not received, thereby being beneficial to reducing the parasitic of the surface acoustic wave, that is, reducing the impedance of the surface acoustic wave device or the parasitic on the admittance curve, and simultaneously, reducing the ripple wave in the passband of the filter formed by the surface acoustic wave device and improving the out-of-band suppression degree of the filter.
On the basis of the above embodiments, in one embodiment of the present application, the surface acoustic wave device may further include:
And a wide end structure body 5, wherein the wide end structure body 5 is positioned on the side surface of the electrode unit 11 in the interdigital electrode 1 and is connected with the electrode unit 11, and the width of the wide end structure body 5 is larger than the width of the electrode unit 11.
The wide end structure 5 is located on one side and/or both sides of the electrode unit 11, i.e., the arrangement of the wide end structure 5 includes three types. First, the wide end structure 5 is located on one side of the interdigital electrode 1, as shown in fig. 7; second, the wide end structures 5 are located on both sides of the interdigital electrode 1, as shown in fig. 8; third, the wide end structures 5 are located on one side and both sides of the interdigital electrode 1, as shown in fig. 9.
It should be noted that when the wide end structures 5 are provided on both sides of one interdigital electrode 1, there is an overlap region between the wide end structures 5 on both sides. Fig. 8 is a schematic diagram showing the wide end structures 5 on both sides of the interdigital electrode 1 fully overlapping.
In this embodiment, by disposing the wide end structure body 5 with a width larger than that of the interdigital electrode 1 on the side surface of the interdigital electrode 1, the lateral leakage of the surface wave can be reduced, and the performance of the surface acoustic wave device can be improved.
Referring to fig. 10 and 11, in one embodiment of the present application, the surface acoustic wave device may further include:
And the reflecting grating 6 is positioned on one side or two sides of the interdigital electrode 1, and the reflecting grating 6 is parallel to the interdigital electrode 1.
In this embodiment, the reflection grating 6 is arranged in the surface acoustic wave device, so that the transverse surface wave can be reflected, and the performance of the device is improved.
Referring to fig. 12 to 13, in one embodiment of the present application, on the basis of any of the above embodiments, the surface acoustic wave device may further include:
an acoustic impedance layer 7, said acoustic impedance layer 7 being located between said substrate 2 and said piezoelectric layer 3.
The acoustic impedance layer 7 includes a first acoustic impedance unit layer 71 and/or a second acoustic impedance unit layer 72; the acoustic impedance of the first acoustic impedance unit layer 71 is larger than the acoustic impedance of the second acoustic impedance unit layer 72, and the acoustic impedance of the second acoustic impedance unit layer 72 is smaller than the acoustic impedance of the piezoelectric layer 3.
In the present application, the acoustic impedance layer 7 includes three cases, the first acoustic impedance layer 7 is a first acoustic impedance unit layer 71, the second acoustic impedance layer 7 is a second acoustic impedance unit layer 72, and the third acoustic impedance layer 7 is a laminated structure of the first acoustic impedance unit layer 71 and the second acoustic impedance unit layer 72.
When the acoustic impedance layer 7 has a laminated structure of the first acoustic impedance unit layer 71 and the second acoustic impedance unit layer 72, the first acoustic impedance unit layer 71 and the second acoustic impedance unit layer 72 are alternately laminated to form a distributed bragg reflection (distributed bragg reflection, DBR) layer. The number of layers of the first acoustic impedance unit layer 71 and the second acoustic impedance unit layer 72 may be between 2 and 12, and may be specifically set according to needs.
When the acoustic impedance layer 7 has a laminated structure of the first acoustic impedance unit layer 71 and the second acoustic impedance unit layer 72, the first acoustic impedance unit layer 71 may be in contact with the substrate 2, that is, the first acoustic impedance unit layer 71, the second acoustic impedance unit layer 72, the first acoustic impedance unit layers 71, …, and the second acoustic impedance unit layer 72 may be laminated in this order, or the second acoustic impedance unit layer 72 may be in contact with the substrate 2, that is, the second acoustic impedance unit layer 72, the first acoustic impedance unit layer 71, the second acoustic impedance unit layers 72, …, and the first acoustic impedance unit layer 71 may be laminated in this order.
The material of the first acoustic impedance unit layer 71 includes, but is not limited to, any one or any combination of aluminum nitride, silicon carbide, molybdenum, and tungsten.
The material of the second sound impedance unit layer 72 includes, but is not limited to, any one or any combination of silicon oxide, aluminum, silicon, and zinc oxide.
By providing the acoustic impedance layer 7 in the surface acoustic wave device in this embodiment, it is possible to reduce the propagation of the surface wave propagating on the surface of the piezoelectric layer 3 longitudinally into the piezoelectric layer 3 or the substrate 2.
On the basis of the above-described embodiment, in one embodiment of the present application, as shown in fig. 14 and 15, when the acoustic impedance layer 7 includes the first acoustic impedance unit layer 71 and the second acoustic impedance unit layer 72, the thickness of the first acoustic impedance unit layer 71 is one-fourth of the wavelength of the transverse wave or one-fourth of the wavelength of the longitudinal wave in the first acoustic impedance unit layer 71, and the thickness of the second acoustic impedance unit layer 72 is one-fourth of the wavelength of the transverse wave or one-fourth of the wavelength of the longitudinal wave in the second acoustic impedance unit layer 72, for reducing the propagation of the surface wave or the longitudinal wave propagating on the surface of the piezoelectric layer 3 into the piezoelectric layer 3 or the substrate 2.
On the basis of the above-described embodiments, in one embodiment of the present application, when the acoustic impedance layer 7 includes the first acoustic impedance unit layer 71 and the second acoustic impedance unit layer 72, the weight range of the first acoustic impedance unit layer 71 to reflect the transverse wave and the longitudinal wave in the first acoustic impedance unit layer 71 is 0.1 to 10, and the weight range of the second acoustic impedance unit layer 72 to reflect the transverse wave and the longitudinal wave in the second acoustic impedance unit layer 72 is 0.1 to 10. That is, the first acoustic impedance unit layer may reflect the transverse wave and the longitudinal wave in the first acoustic impedance unit layer 71 at the same time, and the second acoustic impedance unit layer may reflect the transverse wave and the longitudinal wave in the second acoustic impedance unit layer 72 at the same time.
On the basis of the above-described embodiment, in one embodiment of the present application, as shown in fig. 16 and 17, when the acoustic impedance layer 7 includes the first acoustic impedance unit layer 71 and the second acoustic impedance unit layer 72, the thicknesses of the first acoustic impedance unit layer 71 and the second acoustic impedance unit layer 72 gradually increase or gradually decrease in the direction away from the substrate 2.
The thicknesses of the first acoustic impedance unit layer 71 and the second acoustic impedance unit layer 72 are different, so that the propagation of surface waves and longitudinal waves propagating on the surface of the piezoelectric layer 3 in the longitudinal direction into the piezoelectric layer 3 or the substrate 2 can be reduced.
In summary, the surface acoustic wave device of the present application has the following advantages:
Firstly, an included angle larger than zero exists between the vertical direction of the interdigital electrode and the surface wave propagation direction of the surface acoustic wave device, namely the interdigital electrode is obliquely arranged, so that the parasitic of the surface wave is reduced, namely the parasitic on the impedance or admittance curve of the surface acoustic wave device is reduced, and meanwhile, the ripple wave in the passband of a filter formed by the surface acoustic wave device can be reduced or the out-of-band suppression degree of the filter can be improved;
Second, adding an acoustic impedance layer between the piezoelectric layer and the substrate of the SAW device can reduce the longitudinal propagation of surface waves propagating on the surface of the piezoelectric layer into the piezoelectric layer or the substrate
Thirdly, the electrode heightening body is arranged, so that the transverse leakage of the surface wave can be reduced, and the performance of the surface acoustic wave device, such as the Q value of the surface acoustic wave resonator, the insertion loss of the surface acoustic wave filter and the squareness of the surface acoustic wave filter, is further improved.
The impedance contrast diagram of the surface acoustic wave device shown in fig. 12 of the present application and the surface acoustic wave device in the conventional art is shown in fig. 18, wherein the abscissa is frequency and the ordinate is impedance. As can be seen from fig. 18, the surface acoustic wave device of the present application has a larger electromechanical coupling coefficient up to 11.1%, and can produce a surface acoustic wave filter with a larger bandwidth.
The Q value comparison diagram of the surface acoustic wave device of fig. 12 of the present application and the surface acoustic wave device of the conventional art is shown in fig. 19, wherein the abscissa is frequency and the ordinate is Q value. As can be seen from fig. 19, the surface acoustic wave device of the present application has a higher Q value, and the prepared surface acoustic wave filter has a lower insertion loss and a higher rectangular degree.
Based on the two advantages of fig. 18 and 19, the surface acoustic wave device of the present application can expand the application range of the conventional surface acoustic wave device and improve the performance of the surface acoustic wave filter.
The impedance contrast diagram of the surface acoustic wave device shown in fig. 15 of the present application and the surface acoustic wave device in the conventional art is shown in fig. 20, wherein the abscissa is frequency and the ordinate is impedance. As can be seen from fig. 20, the electromechanical coupling coefficient is greater, reaching 11.6%, and is greater than that of the conventional surface wave device, and is also greater than that of the device structure of fig. 12, so that a surface acoustic wave filter with a greater bandwidth can be manufactured.
The Q value comparison diagram of the surface acoustic wave device of fig. 15 of the present application and the surface acoustic wave device of the conventional art is shown in fig. 21, wherein the abscissa is frequency and the ordinate is Q value. As can be seen from fig. 21, the surface acoustic wave device of the present application has higher Q value, and the prepared surface acoustic wave filter has lower insertion loss and higher rectangular degree.
Based on the two advantages of fig. 20 and 21, the application proposes another surface acoustic wave device structure, which can further expand the application range of the traditional surface acoustic wave device and improve the performance of the surface acoustic wave filter.
The application also provides a filter comprising the surface acoustic wave device according to any one of the embodiments.
In this specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, so that the same or similar parts between the embodiments are referred to each other.
The surface acoustic wave device and the filter provided by the present application are described in detail above. The principles and embodiments of the present application have been described herein with reference to specific examples, the description of which is intended only to facilitate an understanding of the method of the present application and its core ideas. It should be noted that it will be apparent to those skilled in the art that various modifications and adaptations of the application can be made without departing from the principles of the application and these modifications and adaptations are intended to be within the scope of the application as defined in the following claims.
Claims (15)
1. A surface acoustic wave device, comprising:
A substrate (2);
a piezoelectric layer (3) on the substrate (2);
and the interdigital electrode (1) is positioned on the piezoelectric layer (3), and an included angle larger than zero exists between the vertical direction of the interdigital electrode (1) and the surface wave propagation direction of the surface acoustic wave device.
2. The surface acoustic wave device according to claim 1, wherein the electrode units (11) in the interdigital electrode (1) are electrode units (11) of equal thickness.
3. The surface acoustic wave device according to claim 2, further comprising:
and the electrode heightening body (4) is positioned on the electrode units (11) at the two outermost sides of the electrode heightening body (4).
4. A surface acoustic wave device according to claim 3, characterized in that the length of the electrode elevation (4) is equal to the length of the electrode unit (11).
5. A surface acoustic wave device according to claim 3, characterized in that the length of the electrode elevation (4) is smaller than the length of the electrode unit (11) where it is located.
6. The surface acoustic wave device according to claim 1, wherein the included angle ranges from 1 ° to 90 °.
7. The surface acoustic wave device according to claim 1, further comprising:
The wide end structure body (5), the wide end structure body (5) is arranged on the side face of the electrode unit (11) in the interdigital electrode (1) and is connected with the electrode unit (11), and the width of the wide end structure body (5) is larger than that of the electrode unit (11).
8. Surface acoustic wave device according to claim 7, characterized in that the wide end structure (5) is located on one side and/or both sides of the electrode unit (11).
9. The surface acoustic wave device according to claim 1, further comprising:
and the reflecting grating (6) is positioned on one side or two sides of the interdigital electrode (1), and the reflecting grating (6) is parallel to the interdigital electrode (1).
10. The surface acoustic wave device according to any one of claims 1 to 9, further comprising:
-an acoustic impedance layer (7), the acoustic impedance layer (7) being located between the substrate (2) and the piezoelectric layer (3).
11. The surface acoustic wave device according to claim 10, wherein the acoustic impedance layer (7) comprises a first acoustic impedance unit layer (71) and/or a second acoustic impedance unit layer (72); the acoustic impedance of the first acoustic impedance unit layer (71) is larger than that of the second acoustic impedance unit layer (72), and the acoustic impedance of the second acoustic impedance unit layer (72) is smaller than that of the piezoelectric layer (3).
12. The surface acoustic wave device according to claim 11, wherein when the acoustic impedance layer (7) includes a first acoustic impedance element layer (71) and a second acoustic impedance element layer (72), the thickness of the first acoustic impedance element layer (71) is one-fourth of a transverse wavelength or one-fourth of a longitudinal wavelength in the first acoustic impedance element layer (71), and the thickness of the second acoustic impedance element layer (72) is one-fourth of a transverse wavelength or one-fourth of a longitudinal wavelength in the second acoustic impedance element layer (72).
13. The surface acoustic wave device according to claim 11, wherein when the acoustic impedance layer (7) includes a first acoustic impedance element layer (71) and a second acoustic impedance element layer (72), a weight range of the first acoustic impedance element layer (71) for reflecting the transverse wave and the longitudinal wave in the first acoustic impedance element layer (71) is 0.1 to 10, and a weight range of the second acoustic impedance element layer (72) for reflecting the transverse wave and the longitudinal wave in the second acoustic impedance element layer (72) is 0.1 to 10.
14. The surface acoustic wave device according to claim 11, wherein when the acoustic impedance layer (7) includes a first acoustic impedance unit layer (71) and a second acoustic impedance unit layer (72), thicknesses of the first acoustic impedance unit layer (71) and the second acoustic impedance unit layer (72) gradually increase or gradually decrease in a direction away from the substrate (2).
15. A filter comprising the surface acoustic wave device according to any one of claims 1 to 14.
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| CN118353414A (en) * | 2024-06-17 | 2024-07-16 | 天通瑞宏科技有限公司 | A surface acoustic wave resonator and a surface acoustic wave filter |
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