CN220067386U - Bulk acoustic wave resonator and filter - Google Patents
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- CN220067386U CN220067386U CN202321694758.0U CN202321694758U CN220067386U CN 220067386 U CN220067386 U CN 220067386U CN 202321694758 U CN202321694758 U CN 202321694758U CN 220067386 U CN220067386 U CN 220067386U
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- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 description 1
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- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 description 1
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- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 description 1
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Abstract
The utility model discloses a bulk acoustic wave resonator and a filter, and relates to the technical field of resonators, comprising a substrate and a piezoelectric layer arranged on the substrate, wherein an electrode structure and a pseudo electrode structure are arranged on the piezoelectric layer, and the electrode structure comprises a plurality of first electrode plates and a plurality of second electrode plates which are arranged at intervals; the plurality of first electrode plates are connected through an electric connector and a bus bar to form a first interdigital electrode, and the plurality of second electrode plates are connected to form a second interdigital electrode; the first interdigital electrode and the second interdigital electrode are at opposite potentials; the dummy electrode structure comprises a plurality of dummy electrode plates arranged between the first interdigital electrode and the second interdigital electrode, wherein a third distance is arranged between two adjacent dummy electrode plates, and the third distance is equal to the first distance and/or the third distance is equal to the second distance; the dummy electrode pad is at a floating potential and is not connected with an electrical signal. The bulk acoustic wave resonator and the filter provided by the utility model can inhibit the pseudo mode of the bulk acoustic wave resonator and improve the performance of the bulk acoustic wave resonator.
Description
Technical Field
The utility model relates to the technical field of resonators, in particular to a bulk acoustic wave resonator and a filter.
Background
With the rapid development of wireless communication, wireless signals become more and more crowded, and new requirements of integration, miniaturization, low power consumption, high performance, low cost and the like are put forward for a filter working in a radio frequency band. Conventional saw filters are increasingly unable to meet such standards due to frequency and power constraints. The characteristics of the thin film bulk acoustic resonator, such as CMOS process compatibility, high quality factor (Q value), low loss, low temperature coefficient and high power carrying capacity, gradually become hot spots for research of radio frequency filters. However, the film bulk acoustic resonator is difficult to realize ultra-high frequencies above 5GHz operating frequency, and the bandwidth is not satisfactory for 6G communication.
In the prior art, the ultrahigh frequency bulk acoustic wave resonator based on lithium niobate and lithium tantalate film materials can realize ultrahigh frequency operation. Although the resonator has the advantages of ultra-high working frequency of 5GHz and above and effective electromechanical coupling coefficient of 20% and above, the bulk acoustic wave resonator can excite a plurality of pseudo modes when in operation, so that when the bulk acoustic wave resonator is applied to a filter, ripples are generated in the filter band, and the performance of the filter is seriously affected.
Disclosure of Invention
The utility model aims to provide a bulk acoustic wave resonator and a filter, which can inhibit a pseudo mode of the bulk acoustic wave resonator and improve the performance of the bulk acoustic wave resonator.
In one aspect, an embodiment of the present utility model provides a bulk acoustic wave resonator, including a substrate and a piezoelectric layer disposed on the substrate, where an electrode structure and a dummy electrode structure are disposed on the piezoelectric layer, the electrode structure includes a plurality of first electrode plates disposed at intervals and a plurality of second electrode plates disposed at intervals, a first distance is disposed between two adjacent first electrode plates, and a second distance is disposed between two adjacent second electrode plates; the plurality of first electrode plates are connected through an electric connector and a bus bar to form a first interdigital electrode, and the plurality of second electrode plates are connected through the electric connector and the bus bar to form a second interdigital electrode; the first interdigital electrode and the second interdigital electrode are at opposite potentials; the dummy electrode structure comprises a plurality of dummy electrode plates arranged between the first interdigital electrode and the second interdigital electrode, wherein a third distance is arranged between two adjacent dummy electrode plates, and the third distance is equal to the first distance and/or the third distance is equal to the second distance; the dummy electrode pad is at a floating potential and is not connected with an electrical signal.
As an embodiment, the dummy electrode pads are arranged to be staggered with the first electrode pads or the dummy electrode pads are arranged to be staggered with the second electrode pads.
As an embodiment, the dummy electrode pads are provided in a plurality of rows, and the dummy electrode pads in two adjacent rows are staggered.
As one embodiment, the cross-sectional shape of the dummy electrode pads is a circle or a polygon.
As an embodiment, the piezoelectric layer is provided with an acoustic reflection structure, and the acoustic reflection structure is disposed outside the electrode structure.
As an implementation manner, the acoustic reflection structure is separately arranged at two sides of the electrode structure, and the acoustic reflection structure comprises a plurality of acoustic reflection holes, wherein the acoustic reflection holes are staggered with the adjacent first electrode plates, or the acoustic reflection holes are staggered with the adjacent second electrode plates.
As an implementation manner, the plurality of acoustic reflection holes are arranged in an array, and the acoustic reflection holes are through holes, blind holes or stepped holes.
As an embodiment, the acoustic reflection hole is provided with a filler.
As an implementation manner, the electrode structure further includes a bottom electrode, and the bottom electrode is disposed on a side of the piezoelectric layer close to the substrate.
Another aspect of the embodiments of the present utility model provides a filter including the bulk acoustic wave resonator described above.
The beneficial effects of the embodiment of the utility model include:
the utility model provides a bulk acoustic wave resonator, which comprises a substrate and a piezoelectric layer arranged on the substrate, wherein an electrode structure and a pseudo electrode structure are arranged on the piezoelectric layer, the electrode structure comprises a plurality of first electrode plates arranged at intervals and a plurality of second electrode plates arranged at intervals, a first distance is arranged between two adjacent first electrode plates, and a second distance is arranged between two adjacent second electrode plates; the plurality of first electrode plates are connected through an electric connector and a bus bar to form a first interdigital electrode, and the plurality of second electrode plates are connected to form a second interdigital electrode; the first interdigital electrode and the second interdigital electrode are at opposite potentials; the dummy electrode structure comprises a plurality of dummy electrode plates arranged between the first interdigital electrode and the second interdigital electrode, wherein a third distance is arranged between two adjacent dummy electrode plates, and the third distance is equal to the first distance and/or the third distance is equal to the second distance; the dummy electrode pad is at a floating potential and is not connected with an electrical signal. The first interdigital electrode and the interdigital electrode are used for being connected with an external signal, and under the action of the external signal, sound waves which are propagated from the first interdigital electrode to the second interdigital electrode are generated in the piezoelectric layer. Wherein the operating frequency of the ultra-high frequency bulk acoustic wave resonator is determined by the relation (1.1):
wherein f is the working frequency of the bulk acoustic wave resonator, m and n are the orders of modes, and the values are positive integers such as 1,2,3,4 and the like, and theta 0 Represents the sound velocity, p represents the distance between two adjacent first interdigital electrodes and second interdigital electrodes, L represents the structure of the dummy electrode and the first interdigital electrodeThe electrode and the second interdigital electrode overlap each other in the extending direction of the first interdigital electrode. As can be seen from the relation (1.1), the larger the p value is, the arbitrary pseudo mode f n,m The smaller means that the frequency of the spurious mode is reduced, being pushed to a frequency point distant from the main resonance frequency, the effect on the resonance frequency of the main mode is reduced. According to the embodiment of the utility model, the partial electrodes in the first interdigital electrode and the second interdigital electrode are set to be pseudo-electrode structures, and the pseudo-electrode structures are not connected with external signals, so that the distance between the first interdigital electrode and the second interdigital electrode is increased, namely, p is increased under the condition that the capacitance of the resonator is not influenced, the effect of inhibiting pseudo modes is achieved, and the performance of the bulk acoustic wave resonator is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present utility model and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of a bulk acoustic wave resonator according to an embodiment of the present utility model;
FIG. 2 is a schematic diagram of a bulk acoustic wave resonator according to an embodiment of the present utility model;
FIG. 3 is a third schematic diagram of a bulk acoustic wave resonator according to an embodiment of the present utility model;
FIG. 4 is a graph showing the performance of a bulk acoustic wave resonator according to an embodiment of the present utility model versus the performance of the prior art;
FIG. 5 is a schematic diagram of a bulk acoustic wave resonator according to an embodiment of the present utility model;
FIG. 6 is a cross-sectional view taken along line A-A of FIG. 5;
FIG. 7 is a schematic diagram of a bulk acoustic wave resonator according to an embodiment of the present utility model;
FIG. 8 is a cross-sectional view taken along line A-A of FIG. 7;
FIG. 9 is a graph showing a second comparison of performance of a bulk acoustic wave resonator according to an embodiment of the present utility model and a prior art;
FIG. 10 is a schematic diagram of a bulk acoustic wave resonator according to an embodiment of the present utility model;
FIG. 11 is a schematic diagram of a bulk acoustic wave resonator according to an embodiment of the present utility model;
FIG. 12 is a schematic diagram of a bulk acoustic wave resonator according to an embodiment of the present utility model;
fig. 13 is a schematic diagram of a bulk acoustic wave resonator according to an embodiment of the present utility model.
Icon: a 10-bulk acoustic wave resonator; 11-a piezoelectric layer; 12-interdigital electrode structure; 121-a first interdigital electrode; 122-second interdigital electrodes; 123-electrode pairs; 13-a dummy electrode structure; 131-dummy electrode pads; 14-acoustic reflection holes; 15-an acoustically reflective material; 16-bottom electrode.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments of the present utility model. The components of the embodiments of the present utility model generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the utility model, as presented in the figures, is not intended to limit the scope of the utility model, as claimed, but is merely representative of selected embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
Furthermore, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and should not be construed as indicating or implying relative importance.
The embodiment of the utility model provides a bulk acoustic wave resonator 10, as shown in fig. 1,2 and 3, which comprises a substrate and a piezoelectric layer 11 arranged on the substrate, wherein an electrode structure and a dummy electrode structure 13 are arranged on the piezoelectric layer 11, the electrode structure comprises a plurality of first electrode plates arranged at intervals and a plurality of second electrode plates arranged at intervals, a first distance is reserved between two adjacent first electrode plates, and a second distance is reserved between two adjacent second electrode plates; the plurality of first electrode plates are connected through an electric connector and a bus bar to form a first interdigital electrode 121, and the plurality of second electrode plates are connected to form a second interdigital electrode 122; the first interdigital electrode 121 and the second interdigital electrode 122 are at opposite potentials; the dummy electrode structure 13 includes a plurality of dummy electrode pads 131 disposed between the first interdigital electrode 121 and the second interdigital electrode 122, and a third distance is provided between two adjacent dummy electrode pads 131, the third distance being equal to the first distance, and/or the third distance being equal to the second distance; the dummy electrode pads 131 are at a floating potential and are not connected to an electrical signal.
When the bulk acoustic wave resonator 10 provided in the embodiment of the present utility model works, the first interdigital electrode 121 and the second interdigital electrode 122 are connected with external signals, a voltage difference is formed on the piezoelectric layer 11 between the first interdigital electrode 121 and the second interdigital electrode 122, the piezoelectric layer 11 is made of a piezoelectric material, under the action of the voltage difference, an acoustic wave is generated on the piezoelectric layer 11 between the first interdigital electrode 121 and the second interdigital electrode 122 according to the inverse piezoelectric effect, and the acoustic wave propagates along the arrangement direction of the first interdigital electrode 121 and the second interdigital electrode 122. The dummy electrode structure 13 is not connected to an external signal, and is disposed between the first interdigital electrode 121 and the second interdigital electrode 122 as an unpowered electrode.
The operating frequency of the bulk acoustic wave resonator 10 is determined by the relation:
where f is the operating frequency of the bulk acoustic wave resonator 10, m, n is the order of the mode, and the value is1,2,3,4, etc., θ 0 Representing the sound velocity, p represents the distance between adjacent two first and second interdigital electrodes 121 and 122, and L represents the distance at which the dummy electrode structure 13 coincides with the first and second interdigital electrodes 121 and 122 in the extending direction of the first interdigital electrode 121. When the operating frequency of the bulk acoustic wave resonator 10 is determined, the larger p is, the smaller the values of m and n are, and any spurious mode f n,m The smaller. In the embodiment of the utility model, by setting part of electrodes in the first interdigital electrode 121 and the second interdigital electrode 122 as the dummy electrode structure 13, the dummy electrode structure 13 is not connected with an external signal, so that the distance between the first interdigital electrode 121 and the second interdigital electrode 122 is increased, namely P is increased, the frequency f of the dummy mode is reduced, and is pushed to a frequency point far away from the main resonance frequency, the influence on the resonance frequency of the main mode is reduced, and the performance of the bulk acoustic wave resonator 10 is improved.
It should be noted that, the dummy electrode structure 13 in the embodiment of the present utility model increases the distance between the first interdigital electrode 121 and the second interdigital electrode 122 based on the prior art, and the existence of the dummy electrode structure 13 does not affect the connection between the capacitance of the bulk acoustic wave resonator 10 and the external signal.
It should be noted that the form of the dummy electrode structure 13 is not limited in this embodiment, and may be the same as or different from the structure of the first interdigital electrode 121. The specific number and positions of the dummy electrode structures 13 are not particularly limited, and the first interdigital electrode 121 and the second interdigital electrode 122 may form one electrode pair 123, may be disposed between each first interdigital electrode 121 and each second interdigital electrode 122, may be disposed between each electrode pair 123, or may be disposed with a plurality of electrode pairs 123 therebetween. In order to facilitate connection of the plurality of first and second interdigital electrodes 121 and 122 to the positive and negative electrodes of an external signal, electrode bus bars may be provided at both ends of the first interdigital electrode 121, respectively, one electrode bus bar being connected to the same side ends of the plurality of first interdigital electrodes 121, and the other electrode bus bar being connected to the same side ends of the plurality of second interdigital electrodes 122.
Specifically, in operation of the bulk acoustic wave resonator 10,in the piezoelectric layer 11, there are a transverse acoustic wave propagating in the direction in which the first interdigital electrode 121 and the second interdigital electrode 122 are arranged, and also a longitudinal acoustic wave propagating in the direction in which the first interdigital electrode 121 extends, and the frequency f of the bulk acoustic wave resonator 10 is also represented by the relationshipDetermining, wherein d is the thickness of the piezoelectric layer 11; θ l Acoustic velocity for longitudinal waves within the piezoelectric layer 11; θ t The wave velocity of transverse wave sound in the piezoelectric layer 11 is the first electrode plate spacing. When the first interdigital electrode adopts a plurality of first electrode pieces, and the second interdigital electrode adopts a plurality of second electrode pieces, the value of L is reduced, so that f can be increased, and the operating frequency of the bulk acoustic wave resonator 10 can be increased.
The third distance is equal to the first distance and/or the third distance is equal to the second distance; i.e., the distance between two adjacent dummy electrode pads 131 is the same as the distance between two adjacent first electrode pads; alternatively, the distance between the adjacent two dummy electrode pads 131 is the same as the distance between the adjacent two second electrode pads; alternatively, the distance between the adjacent two dummy electrode sheets 131 is the same as the distance between the adjacent two first electrode sheets and the distance between the adjacent two second electrode sheets, the third distance is equal to the first distance, and/or the third distance is equal to the second distance; so that sound waves of the same frequency and wavelength can propagate within the piezoelectric layer 11.
Specific forms of the electrical connection members the embodiments of the present utility model are not limited, and examples thereof may be electrical connection, or may be an electrical bridge as shown in fig. 1, and those skilled in the art may set point connection or electrical bridge, or other forms of electrical connection according to actual situations.
In the bulk acoustic wave resonator 10 provided by the utility model, the first interdigital electrode 121 and the interdigital electrode are used for being connected with the positive electrode and the negative electrode of an external signal, and under the action of the external signal, acoustic waves which are propagated from the first interdigital electrode 121 to the second interdigital electrode 122 are generated in the piezoelectric layer 11. The operating frequency of the ultra-high frequency bulk acoustic wave resonator 10 is determined by the relation (1.1):
as can be seen from the relation (1.1), the larger the p value is, the arbitrary pseudo mode f n,m The smaller means that the frequency of the spurious mode is reduced, being pushed to a frequency point distant from the main resonance frequency, the effect on the resonance frequency of the main mode is reduced. In the embodiment of the utility model, by setting part of electrodes in the first interdigital electrode 121 and the second interdigital electrode 122 as the dummy electrode structure 13, the dummy electrode structure 13 is not connected with an external signal, and the distance between the first interdigital electrode 121 and the second interdigital electrode 122 is increased, namely p is increased under the condition that the capacitance of the resonator is not influenced, so that the effect of inhibiting a dummy mode is achieved, and the performance of the bulk acoustic wave resonator 10 is improved.
Alternatively, the dummy electrode pads 131 are staggered with the first electrode pads, or the dummy electrode pads 131 are staggered with the second electrode pads.
In one implementation manner of the embodiment of the present utility model, the dummy electrode pads 131 are provided with a plurality of columns, and the dummy electrode pads 131 in two adjacent columns are staggered.
When the dummy electrode structure 13 includes the plurality of columns of dummy electrode pads 131, the distance between the first interdigital electrode 121 and the second interdigital electrode 122 can be further increased, thereby further suppressing occurrence of a dummy mode and improving performance of the bulk acoustic wave resonator 10.
When the dummy electrode structure 13 includes a plurality of dummy electrode bars, the distance between adjacent two dummy electrode bars is the same as the original distance of the first and second interdigital electrodes 121 and 122.
Alternatively, as shown in fig. 2 and 3, the dummy electrode pads 131 have a circular or polygonal shape.
As shown in fig. 2, the dummy electrode pads 131 are all circular in shape, and are identical in shape to the first electrode pad and the second electrode pad; as shown in fig. 3, the shapes of the first electrode plate and the second electrode plate are circular, the shape of the dummy electrode plate 131 is diamond, and the shapes of the first electrode plate and the second electrode plate are different from each other, so that the shapes of the dummy electrode plate 131 and the first electrode plate and the second electrode plate can be set by a person skilled in the art according to actual situations.
In order to further verify the improvement of the performance of the bulk acoustic wave resonator 10 by the acoustic reflection structure according to the embodiment of the present utility model, the performance of the bulk acoustic wave resonator 10 without the dummy electrode structure 13 and without the dummy electrode structure 13 is tested, specifically, the test data are shown in fig. 4, the solid line in fig. 9 is the performance curve of the bulk acoustic wave resonator without the dummy electrode structure 13, the dotted line is the performance curve of the bulk acoustic wave resonator 10 according to the embodiment of the present utility model, and as can be seen from fig. 9, the curve according to the embodiment of the present utility model is located above the curve without the dummy electrode structure 13, that is, the bulk acoustic wave resonator 10 provided by the embodiment of the present utility model has better performance.
In one possible implementation of the embodiment of the present utility model, as shown in fig. 5 and 6, the piezoelectric layer 11 is provided with an acoustic reflection structure, and the acoustic reflection structure is disposed outside the electrode structure.
When the first interdigital electrode 121 and the second interdigital electrode 122 are connected with external signals, a transversely-propagating sound wave can be generated in the piezoelectric layer 11 between the first interdigital electrode 121 and the first interdigital electrode 121, and the transversely-propagating sound wave is difficult to avoid leaking after being conducted to the edge of the piezoelectric layer 11 when propagating in the piezoelectric layer 11.
Optionally, the acoustic reflection structure is separately disposed on two sides of the electrode structure, and the acoustic reflection structure includes a plurality of acoustic reflection holes 14, where the acoustic reflection holes 14 are staggered with the adjacent first electrode plates, or the acoustic reflection holes 14 are staggered with the adjacent second electrode plates.
The acoustic reflection structure is disposed at two sides of the electrode structure, and can reflect the acoustic wave from two sides, thereby improving the quality factor of the bulk acoustic wave resonator 10.
Specifically, the acoustic reflection structure includes a plurality of acoustic reflection holes 14 disposed in the piezoelectric layer 11, air is filled in the acoustic reflection holes 14, and the air has a certain reflection effect on the acoustic wave, when the acoustic wave in the piezoelectric layer 11 propagates to the acoustic reflection holes 14, the acoustic reflection holes 14 reflect the acoustic wave propagating to the acoustic wave back into the piezoelectric layer 11, so that leakage of the acoustic wave is avoided, and the quality factor of the bulk acoustic wave resonator 10 is improved.
The depth and cross-sectional shape of the acoustic reflection hole 14 are not limited in the embodiment of the present utility model, and specifically, the hole depth of the acoustic reflection hole 14 may be a part of the piezoelectric layer 11 or may penetrate through the entire piezoelectric layer 11; the cross-sectional shape of the acoustic reflection holes 14 may be circular, quadrangular, elliptical, pentagonal, or other irregular shape, etc.
Alternatively, as shown in fig. 5, a plurality of acoustic reflection holes 14 are disposed at two ends of the interdigital electrode structure 12 in a plurality of rows, and the acoustic reflection holes 14 of two adjacent rows are disposed in a staggered manner.
In order to avoid leakage of sound waves from the piezoelectric layer 11 between two adjacent sound reflection holes 14, the embodiment of the utility model sets multiple rows of sound reflection holes 14, and the adjacent two rows of sound reflection holes 14 are arranged in a staggered manner, so that when the sound waves leaked from the two sound reflection holes 14 in the previous row continue to propagate and meet the sound reflection holes 14 in the next row, the sound waves are reflected back into the effective resonance area by the sound reflection holes 14 in the next row, thereby further avoiding leakage of the sound waves and improving the quality factor of the bulk acoustic wave resonator 10.
In one implementation of an embodiment of the present utility model, as shown in fig. 5, the acoustic reflection holes 14 are through holes, blind holes, or stepped holes.
Alternatively, as shown in fig. 7 and 8, the acoustic reflection holes 14 are filled with filler.
The filling member in the acoustic reflection hole 14 has a reflectivity different from that of the piezoelectric layer 11, and the example filling member may be an acoustic reflection material 15, where the acoustic reflection material 15 has a reflectivity higher than that of air, so that more acoustic waves are reflected by the acoustic reflection material 15 back into the piezoelectric layer 11 to propagate, and further improve the quality factor of the bulk acoustic wave resonator 10.
The specific material of the acoustic reflection material 15 is not limited in the embodiment of the present utility model, as long as it has a relatively high acoustic wave reflectivity and is different from the material of the piezoelectric layer 11, and may be exemplified by silicon nitride, aluminum nitride, tungsten, or various combinations thereof.
In order to further verify that the quality factor of the bulk acoustic wave resonator 10 is improved by the acoustic reflection structure according to the embodiment of the present utility model, the performance of the bulk acoustic wave resonator 10 without the acoustic reflection structure and without the acoustic reflection structure is tested, specifically, the test impedance curve is shown in fig. 9, the broken line in fig. 9 is the impedance curve of the bulk acoustic wave resonance without the acoustic reflection structure, the solid line is the impedance curve of the bulk acoustic wave resonator 10 according to the embodiment of the present utility model, as can be seen from fig. 9, the impedance curve according to the embodiment of the present utility model is more acute, the quality factor of the bulk acoustic wave resonator 10 without the acoustic reflection structure is 349.9, the quality factor of the boost wave resonator according to the embodiment of the present utility model is 872.4, and the quality factor of the bulk acoustic wave resonator 10 according to the embodiment of the present utility model is improved by more than two times.
In one implementation of the embodiment of the present utility model, as shown in fig. 10, 11, 12 and 13, the electrode structure further includes a bottom electrode 16, where the bottom electrode 16 is disposed on a side of the piezoelectric layer 11 near the substrate.
Specifically, a bottom electrode 16 is further disposed between the piezoelectric layer 11 and the substrate, and the bottom electrode 16 includes any one of a patterned bottom electrode 16, a suspension plate bottom electrode 16, and a ground plate bottom electrode 16.
In practical applications, the requirements for the electromechanical coupling coefficient of the bulk acoustic wave resonator 10 are different, so that in order to make the electromechanical coupling coefficient of the bulk acoustic wave resonator 10 adjustable, various modes of the bottom electrode 16 are provided in the embodiments of the present utility model, specifically, as shown in fig. 10, the bottom electrode 16 is not disposed under the piezoelectric layer 11; as shown in fig. 11, an interdigital electrode, which is a patterned bottom electrode 16, is disposed under the piezoelectric layer 11; as shown in fig. 12, a suspension plate bottom electrode 16 is disposed under the piezoelectric layer 11; as shown in fig. 13, a ground plate bottom electrode 16 is provided under the piezoelectric layer 11. Different bottom electrodes 16 have different electromechanical coupling coefficients, and the form of the bottom electrode 16 can be selected by a person skilled in the art according to the actual situation.
The embodiment of the utility model also discloses a filter which comprises the bulk acoustic wave resonator 10. The filter includes the same structure and advantageous effects as the bulk acoustic wave resonator 10 in the previous embodiment. The structure and advantageous effects of the bulk acoustic wave resonator 10 have been described in detail in the foregoing embodiments, and are not described in detail herein.
The above description is only of the preferred embodiments of the present utility model and is not intended to limit the present utility model, but various modifications and variations can be made to the present utility model by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model should be included in the protection scope of the present utility model.
Claims (10)
1. The bulk acoustic wave resonator is characterized by comprising a substrate and a piezoelectric layer arranged on the substrate, wherein an electrode structure and a pseudo electrode structure are arranged on the piezoelectric layer, the electrode structure comprises a plurality of first electrode plates arranged at intervals and a plurality of second electrode plates arranged at intervals, a first distance is reserved between two adjacent first electrode plates, and a second distance is reserved between two adjacent second electrode plates; the plurality of first electrode plates are connected through an electric connector and a bus bar to form a first interdigital electrode, and the plurality of second electrode plates are connected through the electric connector and the bus bar to form a second interdigital electrode; the first interdigital electrode and the second interdigital electrode are in opposite potentials; the dummy electrode structure comprises a plurality of dummy electrode plates arranged between the first interdigital electrode and the second interdigital electrode, wherein a third distance is arranged between two adjacent dummy electrode plates, and/or the third distance is equal to the first distance; the dummy electrode plate is at a floating potential and is not connected with an electric signal.
2. The bulk acoustic wave resonator according to claim 1, characterized in that the dummy electrode pads are arranged interleaved with the first electrode pads or the dummy electrode pads are arranged interleaved with the second electrode pads.
3. The bulk acoustic wave resonator according to claim 1, characterized in that the dummy electrode pads are provided in a plurality of columns, the dummy electrode pads of adjacent two columns being staggered.
4. A bulk acoustic wave resonator according to any of claims 1 to 3, characterized in that the cross-sectional shape of the dummy electrode pads is circular or polygonal.
5. The bulk acoustic wave resonator according to claim 4, characterized in that an acoustic reflection structure is provided on the piezoelectric layer, which is arranged outside the electrode structure.
6. The bulk acoustic wave resonator according to claim 5, characterized in that the acoustic reflection structure is provided separately on both sides of the electrode structure, the acoustic reflection structure comprises a plurality of acoustic reflection holes, and the acoustic reflection holes are staggered with the adjacent first electrode plates, or the acoustic reflection holes are staggered with the adjacent second electrode plates.
7. The bulk acoustic resonator of claim 6, wherein a plurality of acoustic reflection holes are arranged in an array, the acoustic reflection holes being through holes, blind holes, or stepped holes.
8. The bulk acoustic resonator according to claim 6 or 7, characterized in that a filler is provided in the acoustic reflection hole.
9. The bulk acoustic wave resonator according to claim 1, characterized in that the electrode structure further comprises a bottom electrode, which bottom electrode is arranged at a side of the piezoelectric layer close to the substrate.
10. A filter comprising a bulk acoustic wave resonator as claimed in any one of claims 1 to 9.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202321694758.0U CN220067386U (en) | 2023-06-29 | 2023-06-29 | Bulk acoustic wave resonator and filter |
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| CN202321694758.0U CN220067386U (en) | 2023-06-29 | 2023-06-29 | Bulk acoustic wave resonator and filter |
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| CN202321694758.0U Active CN220067386U (en) | 2023-06-29 | 2023-06-29 | Bulk acoustic wave resonator and filter |
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