CN112910433A - Acoustic resonator with laterally excited shear mode - Google Patents
Acoustic resonator with laterally excited shear mode Download PDFInfo
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- CN112910433A CN112910433A CN202110239484.5A CN202110239484A CN112910433A CN 112910433 A CN112910433 A CN 112910433A CN 202110239484 A CN202110239484 A CN 202110239484A CN 112910433 A CN112910433 A CN 112910433A
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- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 4
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- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 3
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Classifications
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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 devices; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
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- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
The invention relates to an acoustic resonator with transverse excitation of shear modes, comprising: the acoustic mirror comprises at least one first acoustic reflection layer and at least one second acoustic reflection layer, and the acoustic impedance of each first acoustic reflection layer is smaller than that of each second acoustic reflection layer; the piezoelectric layer is arranged on the acoustic mirror and comprises lithium niobate of a single crystal material and/or lithium tantalate of a single crystal material; the electrode unit is arranged on the piezoelectric layer and used for forming an electric field; and the transverse reflector is arranged on the piezoelectric layer and comprises a first reflector positioned on the first side of the electrode unit and a second reflector positioned on the second side of the electrode unit, the first side and the second side are opposite sides, and the transverse reflector is used for transversely reflecting the sound wave. The invention can have high electromechanical coupling coefficient and high Q value under the frequency of more than 3 GHz.
Description
Technical Field
The application relates to the technical field of resonators, in particular to an acoustic resonator with a transverse excitation shear mode.
Background
Radio frequency acoustic resonators are small, micro-synthetic structures used for synthesis filtering functions or as frequency sources. The acoustic resonator has a smaller volume and a higher quality factor (Q), so that other types of resonators used in mobile phones, small base stations and Internet of things equipment are replaced, and the acoustic resonator can achieve low loss (low power consumption), high suppression and high signal-to-noise ratio and ultrathin packaging.
With the release of new communication standards (i.e., fifth generation mobile networks), it is necessary to extend the operating range of the resonator to higher frequencies while maintaining a high electromechanical coupling coefficient and a high Q value.
Disclosure of Invention
Based on this, there is a need for an acoustic resonator capable of a laterally excited shear mode with a high electromechanical coupling coefficient and a high Q value at frequencies above 3 GHz.
An acoustic resonator for laterally exciting a shear mode, comprising: the acoustic mirror comprises at least one first acoustic reflection layer and at least one second acoustic reflection layer, and the acoustic impedance of each first acoustic reflection layer is smaller than that of each second acoustic reflection layer; the piezoelectric layer is arranged on the acoustic mirror and comprises lithium niobate of a single crystal material and/or lithium tantalate of a single crystal material; the electrode unit is arranged on the piezoelectric layer and used for forming an electric field; and the transverse reflector is arranged on the piezoelectric layer and comprises a first reflector positioned on the first side of the electrode unit and a second reflector positioned on the second side of the electrode unit, the first side and the second side are opposite sides, and the transverse reflector is used for transversely reflecting the sound wave.
In one embodiment, the electrode units are used to form an electric field mainly parallel to the piezoelectric layer and to generate mechanical waves in shear mode throughout the thickness of the piezoelectric layer.
In one embodiment, the thickness of the first acoustic reflection layer is thicker the farther from the piezoelectric layer; the thickness of the second acoustic reflection layer farther from the piezoelectric layer is thicker.
In one embodiment, the acoustic mirror includes three first acoustic reflection layers and two second acoustic reflection layers, and the first acoustic reflection layers and the second acoustic reflection layers are alternately disposed in the acoustic mirror.
In one embodiment, the material of the first acoustic reflection layer includes at least one of silicon dioxide, aluminum, benzocyclobutene, polyimide and spin-on glass, and the material of the second acoustic reflection layer includes at least one of molybdenum, tungsten, titanium, platinum, aluminum nitride, tungsten oxide and silicon nitride.
In one embodiment, the electrode unit includes a first common electrode, a second common electrode, a plurality of first interdigital electrodes, and a plurality of second interdigital electrodes, each of the first interdigital electrodes is electrically connected to the first common electrode, each of the second interdigital electrodes is electrically connected to the second common electrode, and each of the first interdigital electrodes and each of the second interdigital electrodes are arranged in an insulated manner, the first common electrode is used for accessing an input voltage, and the second common electrode is used for grounding.
In one embodiment, the connecting line direction between the transverse reflectors on both sides of the electrode unit is the propagation direction of the acoustic wave; two side edges of each first acoustic reflection layer and each second acoustic reflection layer of the acoustic mirror in a first direction are aligned, the first direction is perpendicular to the direction of the connecting line on a plane, and the plane is perpendicular to the height direction of the resonator; the first end of each first interdigital electrode is connected with the first common electrode, the first end of each second interdigital electrode is connected with the second common electrode, the orthographic projection of the edge of the first end of each first interdigital electrode on the acoustic mirror is aligned with the first side edge of the acoustic mirror in the first direction, and the orthographic projection of the edge of the first end of each second interdigital electrode on the acoustic mirror is aligned with the second side edge of the acoustic mirror in the first direction.
In one embodiment, each of the first reflector and the second reflector comprises at least one electrode strip, the distance between the center of the electrode strip closest to the electrode unit in the first reflector and the center of the interdigital electrode on the first side edge of the electrode unit is 1/8 to 2 wavelengths of the acoustic wave, and the distance between the center of the electrode strip closest to the electrode unit in the second reflector and the center of the interdigital electrode on the second side edge of the electrode unit is 1/8 to 2 wavelengths of the acoustic wave.
In one embodiment, the display device further includes a first metal piece disposed on the first common electrode and a second metal piece disposed on the second common electrode, wherein thicknesses of the first metal piece and the second metal piece are greater than a thickness of the electrode unit, the first metal piece and the second metal piece are configured to perform acoustic reflection in a first direction, and the first direction is perpendicular to a propagation direction of the acoustic wave.
In one embodiment, the electrode unit and the transverse reflector are made of the same material and are made of metal and/or alloy.
In one embodiment, there is a first acoustic reflector layer that is closer to the piezoelectric layer than all of the second acoustic reflectors.
The acoustic resonator for transversely exciting the shear mode generates an electric field by the electrode unit, and transversely reflects the acoustic wave by the transverse reflector, so that the acoustic wave can be excited to be a transverse shear vibration mode. Because the piezoelectric layer adopts lithium niobate or lithium tantalate which are single crystal materials, the piezoelectric layer can have high electromechanical coupling coefficient and high Q value at the frequency above 3 GHz.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the descriptions of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the following descriptions are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a top view of a portion of the structure of an acoustic resonator for laterally exciting shear modes in one embodiment;
3 FIG. 3 2 3 is 3 a 3 cross 3- 3 sectional 3 view 3 taken 3 along 3 line 3 A 3- 3 A 3' 3 of 3 FIG. 3 1 3; 3
FIG. 3 is a schematic view of the propagation directions of the electric field and the mechanical wave in the piezoelectric layer;
FIG. 4 is a schematic thickness diagram of the reflective layers of the mirror in one embodiment;
FIG. 5 is a schematic diagram of a first reflector in one embodiment;
FIG. 6 is a cross-sectional view taken along line B-B' of FIG. 1;
FIG. 7 is a depiction of the thickness of various layers of an acoustic resonator with laterally excited shear modes in one embodiment;
FIG. 8 is a dimensional representation of the principal structure of the electrode unit and transverse reflector in one embodiment;
FIG. 9 is a simulation of the characteristic admittance of an acoustic resonator of a laterally excited shear mode of an embodiment.
Detailed Description
To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Embodiments of the present application are set forth in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
It will be understood that when an element or layer is referred to as being "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it can be directly on, adjacent to, connected or coupled to the other elements or layers or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly adjacent to," "directly connected to" or "directly coupled to" other elements or layers, there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, doping types and/or sections, these elements, components, regions, layers, doping types and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, doping type or section from another element, component, region, layer, doping type or section. Thus, a first element, component, region, layer, doping type or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention; for example, the first doping type may be made the second doping type, and similarly, the second doping type may be made the first doping type; the first doping type and the second doping type are different doping types, for example, the first doping type may be P-type and the second doping type may be N-type, or the first doping type may be N-type and the second doping type may be P-type.
Spatial relational terms, such as "under," "below," "under," "over," and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements or features described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary terms "under" and "under" can encompass both an orientation of above and below. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations) and the spatial descriptors used herein interpreted accordingly.
As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises/comprising," "includes" or "including," etc., specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, in this specification, the term "and/or" includes any and all combinations of the associated listed items.
Embodiments of the invention are described herein with reference to cross-sectional illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the invention, such that variations from the shapes shown are to be expected, for example, due to manufacturing techniques and/or tolerances. Thus, embodiments of the invention should not be limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing techniques. For example, an implanted region shown as a rectangle will typically have rounded or curved features and/or implant concentration gradients at its edges rather than a binary change from implanted to non-implanted region. Also, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation is performed. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of the present invention.
Bulk Acoustic Wave (BAW) and Surface Acoustic Wave (SAW) resonators are the most commonly used devices for synthesis filters and oscillators between 0.6GHz and 3 GHz. These acoustic devices are commercially successful and are widely used in handset front end modules or as discrete components of radio front ends. Existing bulk acoustic wave and surface acoustic wave devices can exhibit Q values in excess of 1000 and electromechanical coupling coefficients of about 7% -10% at frequencies below 3 GHz. Extending its frequency operating range above 3GHz suffers from several technical uncertainties and physical limitations. The new 5G standard requires electromechanical coupling coefficients in excess of 10%, which cannot be achieved with bulk acoustic wave and surface acoustic wave devices without changing the materials of construction or the mode of operation. Also, material loss constitutes a fundamental limitation on the maximum Q achievable with conventional bulk acoustic wave and surface acoustic wave devices beyond 3 GHz.
In summary, the market demands new devices that can have high electromechanical coupling and high quality factor at frequencies above 3 GHz.
The present application aims to develop a new type of wafer level mechanical/acoustic resonator that is capable of high Q-value and high electromechanical coupling coefficient at frequencies above 3 GHz. The resonator will support the synthesis of high performance pass band filters to meet the new requirements and future generations of the 5G communication standard.
3 fig. 3 1 3 is 3 a 3 top 3 view 3 of 3 a 3 portion 3 of 3 the 3 structure 3 of 3 an 3 acoustic 3 resonator 3 for 3 laterally 3 exciting 3 a 3 shear 3 mode 3 in 3 one 3 embodiment 3, 3 and 3 fig. 3 2 3 is 3 a 3 cross 3- 3 sectional 3 view 3 taken 3 along 3 line 3 a 3- 3 a 3' 3 of 3 fig. 3 1 3. 3 Referring to fig. 1 and 2, the acoustic resonator for laterally exciting a shear mode includes an acoustic mirror 120, a piezoelectric layer 130, an electrode unit, and a lateral reflector, and fig. 1 is mainly for illustrating the shapes of the electrode unit and the lateral reflector in the corresponding embodiments, so that other structures on the piezoelectric layer 130 are omitted.
The electrode unit is disposed on the piezoelectric layer 130 for forming an electric field. The electrode unit may include interdigitated electrodes. In the embodiment shown in fig. 1 and 2, the electrode unit includes a set of first interdigital electrodes 141 and a set of second interdigital electrodes 143, the first interdigital electrodes 141 and the second interdigital electrodes 143 extend in the first direction (Y direction in fig. 1) and are therefore parallel to each other, each first interdigital electrode 141 and each second interdigital electrode 143 are disposed in an insulated manner, the first interdigital electrode 141 is used for accessing an input voltage, and the second interdigital electrode 143 is used for grounding. The electrode unit further includes a first common electrode 142 and a second common electrode 144, one end of each first interdigital electrode 141 is connected to the first common electrode 142, one end of each second interdigital electrode 143 is connected to the second common electrode 144, and the common electrodes are also referred to as bus bars.
The transverse reflectors, which are also provided on the piezoelectric layer 130, may be provided in the same layer as the electrode units, including a first reflector 152 on a first side (left side in fig. 1) of the electrode unit and a second reflector on a second side (right side in fig. 1) of the electrode unit. The transverse reflector is insulated from the electrode unit and used for transversely reflecting the sound wave.
The piezoelectric layer 130 is provided on the acoustic mirror 120. The piezoelectric layer 130 includes lithium niobate of a single crystal material and/or lithium tantalate of a single crystal material.
The acoustic mirror 120 includes at least one first acoustic reflective layer and at least one second acoustic reflective layer, each first acoustic reflective layer having an acoustic impedance less than an acoustic impedance of each second acoustic reflective layer. In one embodiment of the present application, the layer of the acoustic mirror 120 closest to the piezoelectric layer 130 should be the first acoustic reflective layer, i.e., there is a first acoustic reflective layer that is closer to the piezoelectric layer 130 than all of the second acoustic reflective layers. In the embodiment shown in fig. 2, the acoustic mirror 120 includes three first acoustic reflective layers (i.e., the first acoustic reflective layer 121, the first acoustic reflective layer 123, the first acoustic reflective layer 125) and two second acoustic reflective layers (i.e., the second acoustic reflective layer 122 and the second acoustic reflective layer 124), each of which is alternately disposed.
The acoustic resonator for transversely exciting the shear mode generates an electric field by the electrode unit, and transversely reflects the acoustic wave by the transverse reflector, so that the acoustic wave can be excited to be a transverse shear vibration mode. Since the piezoelectric layer 130 is made of lithium niobate or lithium tantalate which is a single crystal material, it can have a high electromechanical coupling coefficient and a high Q value at frequencies above 3 GHz.
Referring to fig. 3, the large arrows in the figure are the directions of the electric fields, and the small arrows are the directions of propagation of the mechanical waves in the shear vibration mode, the electric fields being mainly parallel to the piezoelectric layer 130 and serving to generate the mechanical waves in the shear mode throughout the thickness of the piezoelectric layer 130. The lithium niobate/lithium tantalate of the single crystal material is matched with the electrode unit structure and the transverse reflector structure of the device, so that an optimized shear vibration mode can be obtained, the shear vibration mode has a higher acoustic wave speed, and the frequency can be higher than that of a traditional commercial filter under the condition that the key size (such as the step pitch of the interdigital) of the device is not changed.
In one embodiment of the present application, the electrode unit and the transverse reflector are made of the same material and are made of metal and/or alloy. In one embodiment of the present application, the electrode unit may be made of aluminum (Al), copper (Cu), aluminum copper (AlCu), aluminum silicon copper (AlSiCu), molybdenum (Mo), tungsten (W), silver (Ag), or any other conductive metal.
In the embodiment shown in fig. 2, the acoustic resonator that laterally excites shear modes also includes a carrier wafer 110. The acoustic mirror 120 is disposed on the carrier wafer 110.
In an embodiment of the present application, a bonding auxiliary layer is further disposed between the carrier wafer 110 and the acoustic mirror 120, for assisting the bonding between the carrier wafer 110 and the acoustic mirror 120. In one embodiment of the present application, the bonding assistance layer is a thin layer of silicon dioxide.
In one embodiment of the present application, the first acoustic reflective layers are made of a low acoustic impedance material, and the second acoustic reflective layers are made of a high acoustic impedance material. Wherein the low acoustic impedance material may be at least one of silicon dioxide, aluminum, Benzocyclobutene (BCB), polyimide, and spin on glass (spin on glass), and the high acoustic impedance material may be at least one of molybdenum, tungsten, titanium, platinum, aluminum nitride, aluminum oxide, tungsten oxide, and silicon nitride; it will be appreciated that in other embodiments, other combinations of materials having a greater impedance ratio may be used for the low acoustic impedance material and the high acoustic impedance material.
Each of the first and second acoustic reflective layers of the acoustic mirror 120 may have equal or unequal thicknesses. In one embodiment of the present application, the thicker the thickness of the first acoustic reflective layer the farther from piezoelectric layer 130; this design can achieve a larger Q value as the thickness of the second acoustic reflective layer is thicker the farther away from the piezoelectric layer 130. Referring to fig. 4, in the embodiment shown in fig. 4, the thickness Tl1 of the first acoustic reflection layer 121 < the thickness Tl2 of the first acoustic reflection layer 123 < the thickness Tl3 of the first acoustic reflection layer 125, and the thickness Th1 of the second reflection layer 122 < the thickness Th2 of the second reflection layer 124. It is understood that in other embodiments, the thickness relationship between the first acoustic reflective layer and the second acoustic reflective layer may be set according to other rules, for example, Tl1 ═ Tl2 ═ Tl3, Th1 ═ Th 2; or Tl1> Tl2> Tl3, Th1> Th 2; or Tl1< Tl2, Tl3< Tl2, and Th1< Th 2.
Fig. 1 also shows the position of the acoustic mirror 120 in a top view. The X direction in fig. 1 is the propagation direction of the acoustic wave. Both side edges of each first acoustic reflection layer and each second acoustic reflection layer of the acoustic mirror 120 in the Y direction are aligned. An orthographic projection of an edge of one end of each first interdigital electrode 141, which is far away from the first common electrode 142, on the acoustic mirror 120 is aligned with a first side edge of the acoustic mirror 120 in the Y first direction, and an orthographic projection of an edge of one end of each second interdigital electrode 143, which is far away from the first common electrode 142, on the acoustic mirror 120 is aligned with a second side edge of the acoustic mirror 120 in the Y direction.
The electrode strips of the transverse reflectors may be disconnected from each other as shown in fig. 5, or may be connected to each other by a transverse structure as shown in fig. 1. The electrode strips of the transverse reflector may be arranged parallel to the fingers of the electrode unit.
Fig. 6 is a sectional view taken along line B-B' in fig. 1. In this embodiment, the area of the acoustic mirror 120 is smaller than the area of the piezoelectric layer 130 and the carrier wafer 110, and therefore, a filling layer is further disposed around the acoustic mirror 120. In one embodiment of the present disclosure, the material of the filling layer may include one or more of silicon dioxide, molybdenum, tungsten oxide, or silicon nitride. In one embodiment of the present application, the material of the filling layer is the same as the material of each first acoustic reflection layer, which improves the quality factor of the acoustic resonator.
In the embodiment shown in fig. 6, the acoustic resonator for transverse excitation of shear modes further comprises a first metallic piece 145 provided on the first common electrode 141 and a second metallic piece 147 provided on the second common electrode 143. The thicknesses of the first and second metal pieces 145 and 147 are greater than the thickness of the electrode unit. The first metal piece 145 and the second metal piece 147 serve to make acoustic reflection in the Y direction in fig. 1.
In one embodiment of the present application, the distance W between the center of the electrode bar closest to the electrode element in the first reflector 152 and the center of the inter-digital electrode at the first side edge of the electrode elementg(refer to fig. 8) is 1/8 to 2 wavelengths of the sound wave; the center of the electrode strip closest to the electrode element in the second reflector 154 is spaced from the center of the interdigital electrode at the second side edge of the electrode element by 1/8 to 2 acoustic wavelengths.
The vibration frequency of the mechanical wave of the shear vibration mode formed in the piezoelectric layer 130 is related to the thickness of each film layer and the spacing between adjacent interdigital electrodes in the electrode unit, and the stress is mainly limited to the area without metal coverage between the first interdigital electrode 141 and the second interdigital electrode 143. The important film thickness/spacing of the resonator is labeled in fig. 7 and 8.
In the embodiment shown in fig. 7, the acoustic resonator that laterally excites the shear mode also includes a passivation layer 160. A passivation layer 160 is disposed on the piezoelectric layer 130 and covers the first interdigital electrode 141 and the second interdigital electrode 143. The passivation layer 160 may lower the frequency temperature coefficient of the resonator and passivate the metal electrodes.
Fig. 9 is a simulation result of a Characteristic Admittance (charateristic acceptance) of the acoustic resonator of the laterally excited shear mode of an embodiment. Wherein (b) is the local curve of (a), ktIs the electromechanical coupling coefficient. The characteristic frequency simulation was used to obtain an optimized stacked reflector thickness for a resonant frequency of 4.8 GHz. The same eigenfrequency analysis is used to determine the best averageThe position of the in-plane reflective layer and the relative position of the reflective layer stack with respect to the interdigital electrodes.
In the description herein, references to the description of "some embodiments," "other embodiments," "desired embodiments," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, a schematic description of the above terminology may not necessarily refer to the same embodiment or example.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features of the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. An acoustic resonator for laterally exciting a shear mode, comprising:
the acoustic mirror comprises at least one first acoustic reflection layer and at least one second acoustic reflection layer, and the acoustic impedance of each first acoustic reflection layer is smaller than that of each second acoustic reflection layer;
the piezoelectric layer is arranged on the acoustic mirror and comprises lithium niobate of a single crystal material and/or lithium tantalate of a single crystal material;
the electrode unit is arranged on the piezoelectric layer and used for forming an electric field;
and the transverse reflector is arranged on the piezoelectric layer and comprises a first reflector positioned on the first side of the electrode unit and a second reflector positioned on the second side of the electrode unit, the first side and the second side are opposite sides, and the transverse reflector is used for transversely reflecting the sound wave.
2. A laterally excited shear mode acoustic resonator as claimed in claim 1, in which the electrode elements are arranged to form an electric field predominantly parallel to the piezoelectric layer and to generate mechanical waves in shear mode throughout the thickness of the piezoelectric layer.
3. The laterally-excited shear mode acoustic resonator of claim 1, wherein the thickness of the first acoustic reflecting layer is thicker the farther from the piezoelectric layer; the thickness of the second acoustic reflection layer farther from the piezoelectric layer is thicker.
4. The laterally excited shear mode acoustic resonator of claim 1, wherein the acoustic mirror comprises three first and two second acoustic reflective layers, and wherein the first and second acoustic reflective layers alternate in the acoustic mirror.
5. The laterally excited shear mode acoustic resonator of claim 1, wherein the first acoustic reflective layer comprises at least one of silicon dioxide, aluminum, benzocyclobutene, polyimide, and spin-on glass, and the second acoustic reflective layer comprises at least one of molybdenum, tungsten, titanium, platinum, aluminum nitride, tungsten oxide, and silicon nitride.
6. The transversely excited shear mode acoustic resonator according to claim 1, wherein the electrode unit comprises a first common electrode, a second common electrode, a plurality of first interdigital electrodes and a plurality of second interdigital electrodes, each of the first interdigital electrodes is electrically connected to the first common electrode, each of the second interdigital electrodes is electrically connected to the second common electrode, and each of the first interdigital electrodes and each of the second interdigital electrodes are insulated from each other, the first common electrode is used for connecting to an input voltage, and the second common electrode is used for grounding.
7. The acoustic resonator for transverse-excited shear modes according to claim 6, wherein the direction of the line between the transverse reflectors on both sides of the electrode unit is the propagation direction of the acoustic wave; two side edges of each first acoustic reflection layer and each second acoustic reflection layer of the acoustic mirror in a first direction are aligned, the first direction is perpendicular to the direction of the connecting line on a plane, and the plane is perpendicular to the height direction of the resonator; the first end of each first interdigital electrode is connected with the first common electrode, the first end of each second interdigital electrode is connected with the second common electrode, the orthographic projection of the edge of the first end of each first interdigital electrode on the acoustic mirror is aligned with the first side edge of the acoustic mirror in the first direction, and the orthographic projection of the edge of the first end of each second interdigital electrode on the acoustic mirror is aligned with the second side edge of the acoustic mirror in the first direction.
8. The laterally excited shear mode acoustic resonator of claim 6, wherein the first reflector and the second reflector each comprise at least one electrode strip, a center of a closest one of the first reflectors to the electrode elements is spaced from a center of the interdigital electrode on the first side edge of the electrode elements by 1/8 to 2 wavelengths of the acoustic wave, and a center of a closest one of the second reflectors to the electrode elements is spaced from a center of the interdigital electrode on the second side edge of the electrode elements by 1/8 to 2 wavelengths of the acoustic wave.
9. The laterally excited shear mode acoustic resonator of claim 6, further comprising a first metallic member disposed on the first common electrode and a second metallic member disposed on the second common electrode, the first and second metallic members having a thickness greater than a thickness of the electrode unit, the first and second metallic members configured to perform acoustic reflection in a first direction perpendicular to a propagation direction of the acoustic wave.
10. A laterally excited shear mode acoustic resonator as claimed in claim 1, in which the electrode elements are of the same material and are of metal and/or alloy as the lateral reflector.
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| US17/998,242 US20230216479A1 (en) | 2021-03-04 | 2022-03-03 | Acoustic resonator in transverse excitation shear mode |
| PCT/CN2022/078932 WO2022184118A1 (en) | 2021-03-04 | 2022-03-03 | Acoustic resonator in transverse excitation shear mode |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114389561A (en) * | 2021-12-21 | 2022-04-22 | 无锡市好达电子股份有限公司 | Mixed structure acoustic wave device |
| WO2022184118A1 (en) * | 2021-03-04 | 2022-09-09 | 偲百创(深圳)科技有限公司 | Acoustic resonator in transverse excitation shear mode |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1933327A (en) * | 2005-09-13 | 2007-03-21 | 精工爱普生株式会社 | Surface acoustic wave device and manufacturing method thereof |
| US20120080979A1 (en) * | 2010-10-05 | 2012-04-05 | Vectron International Gmbh & Co. Kg | Surface acoustic wave component |
| CN107070428A (en) * | 2015-12-22 | 2017-08-18 | 株式会社村田制作所 | Electronic unit |
| CN109842397A (en) * | 2017-11-29 | 2019-06-04 | 株式会社村田制作所 | Acoustic wave device, high-frequency front-end circuit and communication device |
| CN110572137A (en) * | 2019-10-08 | 2019-12-13 | 开元通信技术（厦门）有限公司 | Acoustic wave device and filtering device |
| CN215072337U (en) * | 2021-03-04 | 2021-12-07 | 偲百创(深圳)科技有限公司 | Acoustic resonator with transverse excitation shear mode |
-
2021
- 2021-03-04 CN CN202110239484.5A patent/CN112910433A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1933327A (en) * | 2005-09-13 | 2007-03-21 | 精工爱普生株式会社 | Surface acoustic wave device and manufacturing method thereof |
| US20120080979A1 (en) * | 2010-10-05 | 2012-04-05 | Vectron International Gmbh & Co. Kg | Surface acoustic wave component |
| CN107070428A (en) * | 2015-12-22 | 2017-08-18 | 株式会社村田制作所 | Electronic unit |
| CN109842397A (en) * | 2017-11-29 | 2019-06-04 | 株式会社村田制作所 | Acoustic wave device, high-frequency front-end circuit and communication device |
| CN110572137A (en) * | 2019-10-08 | 2019-12-13 | 开元通信技术（厦门）有限公司 | Acoustic wave device and filtering device |
| CN215072337U (en) * | 2021-03-04 | 2021-12-07 | 偲百创(深圳)科技有限公司 | Acoustic resonator with transverse excitation shear mode |
Non-Patent Citations (2)
| Title |
|---|
| JUNAID MUNIR ET AL.: "Effects of compensating the temperature coefficient of frequency with the acoustic reflector layers on the overall performance of solidly mounted resonators", 《ELSEVIER》, vol. 74, 28 February 2017 (2017-02-28), pages 153 - 160 * |
| 李秋良;董志贵;: "声表面波同步谐振器原理与设计", 通信电源技术, no. 09, 10 May 2020 (2020-05-10) * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022184118A1 (en) * | 2021-03-04 | 2022-09-09 | 偲百创(深圳)科技有限公司 | Acoustic resonator in transverse excitation shear mode |
| CN114389561A (en) * | 2021-12-21 | 2022-04-22 | 无锡市好达电子股份有限公司 | Mixed structure acoustic wave device |
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