CN112003581A - Bulk acoustic wave resonator - Google Patents
Bulk acoustic wave resonator Download PDFInfo
- Publication number
- CN112003581A CN112003581A CN202010828584.7A CN202010828584A CN112003581A CN 112003581 A CN112003581 A CN 112003581A CN 202010828584 A CN202010828584 A CN 202010828584A CN 112003581 A CN112003581 A CN 112003581A
- Authority
- CN
- China
- Prior art keywords
- cavity
- acoustic wave
- bulk acoustic
- wave resonator
- piezoelectric layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000000758 substrate Substances 0.000 claims abstract description 28
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 8
- 239000007769 metal material Substances 0.000 claims description 4
- 239000000377 silicon dioxide Substances 0.000 claims description 4
- 235000012239 silicon dioxide Nutrition 0.000 claims description 3
- 230000003071 parasitic effect Effects 0.000 abstract description 7
- 238000010586 diagram Methods 0.000 description 16
- 239000000463 material Substances 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 230000008859 change Effects 0.000 description 4
- 229910021389 graphene Inorganic materials 0.000 description 4
- 230000001902 propagating effect Effects 0.000 description 4
- 230000001788 irregular Effects 0.000 description 3
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 239000011651 chromium Substances 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 239000011733 molybdenum Substances 0.000 description 2
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- 239000010937 tungsten Substances 0.000 description 2
- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 description 1
- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 description 1
- 229910002601 GaN Inorganic materials 0.000 description 1
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- JMASRVWKEDWRBT-UHFFFAOYSA-N Gallium nitride Chemical compound [Ga]#N JMASRVWKEDWRBT-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- HFGPZNIAWCZYJU-UHFFFAOYSA-N lead zirconate titanate Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ti+4].[Zr+4].[Pb+2] HFGPZNIAWCZYJU-UHFFFAOYSA-N 0.000 description 1
- 229910052451 lead zirconate titanate Inorganic materials 0.000 description 1
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 description 1
- 238000010295 mobile communication Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 229910052594 sapphire Inorganic materials 0.000 description 1
- 239000010980 sapphire Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02007—Details of bulk acoustic wave devices
- H03H9/02086—Means for compensation or elimination of undesirable effects
-
- 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
- H03H9/171—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
The invention discloses a bulk acoustic wave resonator. The bulk acoustic wave resonator includes: the device comprises a substrate, and a reflecting structure, a bottom electrode, a piezoelectric layer and a top electrode which are sequentially arranged on the substrate; the bulk acoustic wave resonator comprises a resonance area, the resonance area comprises edge areas, at least one cavity is arranged in the edge areas, and the top and/or the bottom of each cavity is/are located inside the piezoelectric layer. The invention can avoid the parasitic mode formed by the lateral wave during resonance and reduce the energy leakage of the lateral wave.
Description
Technical Field
The invention relates to the technical field of resonators, in particular to a bulk acoustic wave resonator.
Background
FBAR (film bulk acoustic resonator) is widely used in the field of mobile communication due to its advantages of small size, semiconductor process compatibility, high Q value, etc. Resonators are the basic elements that make up a filter, and their performance directly affects the performance of the filter.
The resonator forms a longitudinal bulk acoustic wave when operating, but the longitudinal bulk acoustic wave generates a lateral wave in the piezoelectric layer when propagating on the piezoelectric layer due to the physical poisson effect of the piezoelectric layer. While lateral waves cause energy leakage and form parasitic modes at resonance.
Disclosure of Invention
The invention provides a bulk acoustic wave resonator which can prevent side waves from forming a parasitic mode during resonance and reduce energy leakage of the side waves.
The invention provides a bulk acoustic wave resonator, which comprises a substrate, and a reflecting structure, a bottom electrode, a piezoelectric layer and a top electrode which are sequentially arranged on the substrate;
the bulk acoustic wave resonator comprises a resonance area, the resonance area comprises edge areas, at least one cavity is arranged in the edge areas, and the top and/or the bottom of each cavity is/are located inside the piezoelectric layer.
Preferably, a top of the cavity is located inside the piezoelectric layer and a bottom of the cavity extends to a top surface of the bottom electrode, an inside of the bottom electrode, or a bottom surface of the bottom electrode.
Preferably, the bottom of the cavity is located inside the piezoelectric layer, and the top of the cavity extends to the bottom surface of the top electrode, the inside of the top electrode, or the top surface of the top electrode.
Preferably, the resonance region further comprises a central region, the edge region being disposed around the central region;
the spacing of the at least one cavity in the circumferential direction is less than a preset threshold.
Preferably, the at least one cavity comprises at least one first cavity;
the first cavity is disposed around the central region, and an orthographic projection of the first cavity on the substrate is a closed shape.
Preferably, the at least one cavity comprises at least one second cavity;
the second cavity is arranged around the central area, and an orthographic projection of the second cavity on the substrate is in a non-closed shape with an opening, and the distance of the opening is smaller than the preset threshold value.
Preferably, the at least one cavity comprises a plurality of third cavities;
the plurality of third cavities are arranged at intervals in the surrounding direction, and the interval distance between any two adjacent third cavities is smaller than the preset threshold value.
Preferably, the preset threshold is 50 μm.
Preferably, the length of the edge region in a direction toward the center of the resonance region is less than 3 μm.
Preferably, the cavity is filled with any one of air and a non-metallic material including silicon dioxide.
The invention has the beneficial effects that: the at least one cavity is arranged in the edge area of the resonant area, so that the top and/or the bottom of each cavity is/are positioned in the piezoelectric layer, the lateral waves transmitted to the cavity (namely the edge area of the resonant area of the piezoelectric layer) can change the transmission direction through cavity reflection, and the lateral waves at the edge area of the resonant area of the piezoelectric layer cannot be leaked to a non-resonant area, so that the energy leakage of the lateral waves is reduced, the parasitic mode formed by the lateral waves during resonance is avoided, and the quality of the resonator is improved.
Drawings
In order to illustrate the embodiments or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the invention, and it is obvious for a person skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic diagram of a first structure of a bulk acoustic wave resonator according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a second structure of a bulk acoustic wave resonator according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a bulk acoustic wave resonator according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a fourth structure of a bulk acoustic wave resonator according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a fifth bulk acoustic wave resonator according to an embodiment of the present invention;
fig. 6 is a schematic diagram illustrating a sixth structure of a bulk acoustic wave resonator according to an embodiment of the present invention;
fig. 7 is a seventh structural diagram of a bulk acoustic wave resonator according to an embodiment of the present invention;
fig. 8 is an eighth structural schematic diagram of a bulk acoustic wave resonator according to an embodiment of the present invention;
fig. 9 is a first schematic diagram of a cavity in an edge region of a bulk acoustic wave resonator according to an embodiment of the present invention;
fig. 10 is a second schematic diagram of a cavity in an edge region of a bulk acoustic wave resonator according to an embodiment of the present invention;
fig. 11 is a third schematic diagram of a cavity in an edge region of a bulk acoustic wave resonator according to an embodiment of the present invention;
fig. 12 is a fourth schematic diagram of a cavity in an edge region of a bulk acoustic wave resonator according to an embodiment of the present invention;
FIG. 13 is a circuit diagram of a filter provided in accordance with an embodiment of the present invention;
fig. 14 is another circuit diagram of a filter according to an embodiment of the present invention.
Detailed Description
Specific structural and functional details disclosed herein are merely representative and are provided for purposes of describing example embodiments of the present invention. The present invention may, however, be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein.
In the description of the present invention, it is to be understood that the terms "center", "lateral", "upper", "lower", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified. Furthermore, the term "comprises" and any variations thereof is intended to cover non-exclusive inclusions.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Fig. 1 is a schematic structural diagram of a bulk acoustic wave resonator according to an embodiment of the present invention.
As shown in fig. 1, the bulk acoustic wave resonator provided in the embodiment of the present invention includes a substrate 1, and a reflection structure 2, a bottom electrode 3, a piezoelectric layer 4, and a top electrode 5 sequentially disposed on the substrate. In particular, the reflecting structure 2 is located on the substrate 1, the bottom electrode 3 is located on the reflecting structure 2 and the substrate 1, the piezoelectric layer 4 is located on the bottom electrode 3 and the substrate 1, and the top electrode 5 is located on the piezoelectric layer 4.
The reflective structure 2 may be a resonant cavity or a reflector, such as a Bragg reflector (Bragg reflector). When the reflective structure 2 is a resonant cavity, a sacrificial layer (not shown) may be formed on the substrate 1, and the sacrificial layer may have a sidewall having a slope with respect to the upper surface of the substrate 1, and the slope of the sidewall may be 35 degrees. Because the sacrificial layer is made of transition materials, after the bottom electrode 3, the piezoelectric layer 4 and the top electrode 5 are sequentially formed on the substrate 1 and the sacrificial layer, the sacrificial layer can be released through the release hole, so that a cavity, namely a resonant cavity, is formed at the sacrificial layer, the longitudinal section of the resonant cavity can be isosceles trapezoid, and the base angle of the isosceles trapezoid can be 35 degrees. The resonant cavity is a boundary condition for forming the resonator vibration.
The substrate 1 may be silicon, glass, sapphire, gallium nitride, gallium arsenide, lithium niobate, lithium tantalate, or the like. The bottom electrode 3 may be one or more of molybdenum, tungsten, chromium, aluminum, copper, Graphene (Graphene) in combination. The piezoelectric layer 4 has a crystal of <002> and may be aluminum nitride, zinc oxide, lead zirconate titanate, or the above-mentioned material doped with a rare earth element. The top electrode 5 may be one or a combination of molybdenum, tungsten, chromium, aluminum, copper, Graphene (Graphene).
The bulk acoustic wave resonator includes a resonance region 6 and a non-resonance region. The resonance region 6 refers to a region that vibrates in a predetermined direction by a piezoelectric phenomenon to generate resonance when electric energy is applied to the bottom electrode 3 and the top electrode 5 to induce an electric field in the piezoelectric layer 4, and for example, a region where the reflective structure 2, the bottom electrode 3, the piezoelectric layer 4, and the top electrode 5 overlap is the resonance region 6. The non-resonance region refers to a region where resonance does not occur by a piezoelectric phenomenon even if electric energy is applied to the bottom electrode 3 and the top electrode 5. The non-resonance region may be divided into a first non-resonance region 71 and a second non-resonance region 72 located on both sides of the resonance region 6.
Specifically, the bottom electrode 3 is located in the first non-resonance region 71 and the resonance region 6, the piezoelectric layer 4 is located in the resonance region 6, the first non-resonance region 71, and the second non-resonance region 72, and the top electrode 5 is located in the resonance region 6 and the second non-resonance region 72. The bottom electrode 3 and the top electrode 5 have the same shape on the substrate 1, and may include any one or a combination of shapes of a semicircle, a triangle, a rectangle, and an irregular polygon. For example, the bottom electrode 3 and the top electrode 5 are each a combined shape formed of a semicircle and a triangle.
As shown in fig. 1, the resonance region 6 may include a central region 61 and an edge region 62 disposed around the central region 61. Preferably, the length of the edge region 62 in the direction towards the centre of the resonance zone 6 is less than 3 μm. At least one cavity 7 is provided in the edge region 62, the top and/or bottom of each cavity 7 being located inside the piezoelectric layer 4. Note that the inside of the piezoelectric layer 4 refers to a position between the bottom surface and the top surface of the piezoelectric layer 4, and does not include the bottom surface and the top surface of the piezoelectric layer 4. That is, at least one of the top and the bottom of each cavity 7 is disposed in the piezoelectric layer 4, so as to ensure that the lateral wave can be reflected by the piezoelectric layer 4 at the top and/or the bottom after propagating into the cavity 7, change the propagation direction, and achieve the purpose of reducing the energy leakage of the lateral wave and avoiding the lateral wave forming a parasitic mode at the time of resonance.
If the top of one cavity 7 is located inside the piezoelectric layer 4, the bottom of that cavity 7 can be located inside the piezoelectric layer 4, as shown in fig. 1; the bottom of the cavity 7 may extend to the top surface of the bottom electrode 3, i.e. the bottom surface of the piezoelectric layer 4, as shown in fig. 2; the bottom of the cavity 7 may extend into the interior of the bottom electrode 3, as shown in fig. 3; the bottom of the cavity 7 may extend to the bottom surface of the bottom electrode 3, i.e. through the bottom electrode 3, to communicate with the resonant cavity, as shown in fig. 4.
If the bottom of one cavity 7 is located inside the piezoelectric layer 4, the top of that cavity 7 can be located inside the piezoelectric layer 4, as shown in fig. 1; the top of the cavity 7 may extend to the bottom surface of the top electrode 5, i.e. the top surface of the piezoelectric layer 4, as shown in fig. 5; the top of the cavity 7 may extend into the top electrode 3, as shown in fig. 6; the top of the cavity 7 may extend to the top surface of the top electrode 3, i.e. through the top electrode 3, as shown in fig. 7.
One cavity 7 may be provided in the edge region 62, or a plurality of cavities 7 may be provided, and the lengths and positions of the different cavities 7 in the direction perpendicular to the substrate 1 may be the same or different. For example, the edge region 62 in fig. 8 is provided with three cavities 71, 72, 73. The top of the cavity 71 is located inside the piezoelectric layer 4 and the bottom extends to the top surface of the bottom electrode 3; the bottom of the cavity 72 is located inside the piezoelectric layer 4 and the top extends inside the top electrode 5; both the bottom and the top of the cavity 73 are located inside the piezoelectric layer 4, i.e. the cavity 73 is located inside the piezoelectric layer 4.
In addition, the cavity 7 may be filled with air or other non-metallic materials, such as silicon dioxide, SiO2. When the cavity 7 is filled with air, it can be formed by a method similar to that of a resonator. For example, when the cavity 7 shown in fig. 1 is manufactured, a first piezoelectric sub-layer (not shown in the figure) is formed on the bottom electrode 3 and the substrate 1, a groove is formed in the first piezoelectric sub-layer, a sacrificial material is filled in the groove, a second piezoelectric sub-layer (not shown in the figure) is further formed on the first piezoelectric sub-layer, the first piezoelectric sub-layer and the second piezoelectric sub-layer form a piezoelectric layer 4, and after the top electrode 5 is formed on the second piezoelectric sub-layer, the sacrificial material in the groove is released through a release hole, so that the cavity 7 filled with air is formed. For another example, when the cavity 7 shown in fig. 6 is formed, a first top electrode layer (not shown) is formed on the piezoelectric layer 4, a groove is formed in the piezoelectric layer 4 and the first top electrode layer, a sacrificial material is filled in the groove, and a second top electrode layer is formed on the first top electrode layer, the first top electrode layer and the second top electrode layer constitute the top electrode 5, and the sacrificial material in the groove is released through the release hole to form the cavity 7 filled with air.
Further, as shown in fig. 9 to 12, at least one cavity 7 in the edge region 62 is disposed around the central region 61, and a pitch of the at least one cavity 7 in the surrounding direction a is smaller than a preset threshold. That is, the continuous length of the edge region 62 without cavities in the surrounding direction a is less than the preset threshold value, so that at least one cavity 7 in the edge region 62 satisfies the destructive interference condition of the resonator lateral wave resonance. Preferably, the preset threshold may be 50 μm.
As shown in fig. 9, the at least one cavity 7 in the edge region 62 may comprise at least one first cavity 74, the first cavity 74 being arranged around the central region 61, i.e. the first cavity 74 extends in the surrounding direction a, and an orthographic projection of the first cavity 74 on the substrate 1 has a closed shape. That is, the first cavity 74 may be a closed structure surrounding the central region 61. The closed shape may be a ring, a rectangle, an irregular polygon, etc., and is not limited herein.
Since the first cavities 74 are closed, the edge regions 62 are each provided with a cavity in the direction of rotation a, i.e. at least one cavity in the edge region 61 has a spacing of 0 in the direction of rotation a. If a plurality of first cavities 74 are provided in the edge region 62, the plurality of first cavities 74 may be arranged in sequence in a direction toward the central region 61. Other cavities 7 may also be provided in the edge region 62, and the shape and position of the orthographic projection of the other cavities 7 on the substrate 1 are not particularly limited.
As shown in fig. 10, the at least one cavity 7 in the edge region 62 may comprise at least one second cavity 75, the second cavity 75 being arranged around the central region 61, i.e. the second cavity 75 extends in the surrounding direction a, and an orthographic projection of the second cavity 75 on the substrate 1 has an open, non-closed shape. That is, the second cavity 75 may be a non-closed structure surrounding the central region 61. The non-closed shape may be a ring shape having an opening, a rectangle, an irregular polygon, etc., and is not particularly limited herein.
Since the second cavity 75 is a non-closed structure with an opening, the edge region 62 has no cavities in the surrounding direction a and is spaced apart by the opening distance D1, and the opening distance D1 is smaller than the preset threshold. If a plurality of second cavities 75 are disposed in the edge region 62, the plurality of second cavities 75 may be sequentially arranged along the direction toward the central region 61, and the opening positions in different second cavities 75 may be the same or different. Other cavities 7 may also be provided in the edge region 62, and the shape and position of the orthographic projection of the other cavities 7 on the substrate 1 are not particularly limited.
As shown in fig. 11, the at least one cavity 7 in the edge region 62 may include a plurality of third cavities 76, and the plurality of third cavities 76 are spaced apart in the circumferential direction a, i.e., the orthographic projection of the plurality of third cavities 76 on the substrate 1 is spaced apart. The continuous length of the edge region 62 without cavities in the circumferential direction a is the distance between any two adjacent third cavities 76 in the circumferential direction a, i.e. the distance between at least one cavity in the edge region 62 in the circumferential direction a is the distance between any two adjacent third cavities 76 in the circumferential direction a.
As shown in fig. 11, if two adjacent third cavities 76 do not overlap in the direction toward the central area 61, the distance D2 between the two adjacent third cavities 76 in the surrounding direction a is greater than 0 and smaller than the preset threshold. As shown in fig. 12, if one end of each of the adjacent two third cavities 76 overlaps in the direction toward the central area 61, the distance between the adjacent two third cavities 76 in the surrounding direction a is 0 at the overlapping position, and the distance D2 between the adjacent two third cavities 76 in the surrounding direction a is greater than 0 and smaller than the preset threshold value at the non-overlapping position. Other cavities 7 may also be provided in the edge region 62, and the shape and position of the orthographic projection of the other cavities 7 on the substrate 1 are not particularly limited.
It should be noted that only the first cavity 74, the second cavity 75, or the third cavity 76 may be provided in the edge region 62, or multiple cavities among the first cavity 74, the second cavity 75, and the third cavity 76 may be provided at the same time. On the basis of this, further cavities 7 can also be provided in the edge region 62.
Further, the piezoelectric layer 4 in the first non-resonant region 71 is further provided with an opening, and a first pad (not shown) is filled in the opening, so that the first pad is electrically connected with the bottom electrode 3 for transmitting signals with the outside. A second pad (not shown) is disposed on the top electrode 5 in the second non-resonant region 72, so that the second pad is electrically connected to the top electrode 5 for transmitting signals to the outside.
As can be seen from the above, the bulk acoustic wave resonator provided in the embodiment of the present invention can be configured with at least one cavity in the edge region of the resonance region, so that the top and/or the bottom of each cavity is located inside the piezoelectric layer, and the lateral wave propagating to the cavity (i.e., the edge region of the piezoelectric layer resonance region) can be reflected by the cavity to change the propagation direction, thereby ensuring that the lateral wave in the edge region of the piezoelectric layer resonance region does not leak to the non-resonance region, so as to reduce the energy leakage of the lateral wave, avoid the lateral wave from forming a parasitic mode during resonance, and improve the resonator quality.
Correspondingly, the embodiment of the invention also provides a filter, which can comprise at least one bulk acoustic wave resonator in the above embodiment.
As shown in fig. 13, the filter in this embodiment may be a ladder filter, where the ladder filter includes a first resonator 91 and a second resonator 92, and each resonator is a bulk acoustic wave resonator in the above embodiment, and details thereof are not repeated here. Wherein, the second pad electrically connected to the top electrode of the first resonator 91 and the second pad electrically connected to the top electrode of the second resonator 92 are the same pad, and constitute a signal input terminal; the first pad to which the bottom electrode of the first resonator 91 is connected constitutes a ground terminal, and the first pad to which the bottom electrode of the second resonator 92 is connected constitutes a signal output terminal.
In addition, the filter in this embodiment may also be a lattice type filter, where the lattice type filter includes four resonators 10, and each resonator 10 is the bulk acoustic wave resonator in the above embodiment, and details are not described here again. A circuit diagram of the lattice type filter is shown in fig. 14.
As can be seen from the above, the filter provided in the embodiment of the present invention can be configured with at least one cavity in the edge region of the resonant region, so that the top and/or the bottom of each cavity is located inside the piezoelectric layer, and the lateral waves propagating to the cavity (i.e., the edge region of the piezoelectric layer resonant region) can be reflected by the cavity to change the propagation direction, thereby ensuring that the lateral waves in the edge region of the piezoelectric layer resonant region do not leak to the non-resonant region, so as to reduce the energy leakage of the lateral waves, avoid the lateral waves from forming a parasitic mode during resonance, improve the resonator quality, and further improve the filter quality.
In summary, although the present invention has been described with reference to the preferred embodiments, the above-described preferred embodiments are not intended to limit the present invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, therefore, the scope of the present invention shall be determined by the appended claims.
Claims (10)
1. A bulk acoustic wave resonator is characterized by comprising a substrate, a reflecting structure, a bottom electrode, a piezoelectric layer and a top electrode, wherein the reflecting structure, the bottom electrode, the piezoelectric layer and the top electrode are sequentially arranged on the substrate;
the bulk acoustic wave resonator comprises a resonance area, the resonance area comprises edge areas, at least one cavity is arranged in the edge areas, and the top and/or the bottom of each cavity is/are located inside the piezoelectric layer.
2. The bulk acoustic wave resonator according to claim 1, wherein a top of the cavity is located inside the piezoelectric layer and a bottom of the cavity extends to a top surface of the bottom electrode, inside of the bottom electrode, or a bottom surface of the bottom electrode.
3. The bulk acoustic wave resonator according to claim 1, wherein a bottom of the cavity is located inside the piezoelectric layer, and a top of the cavity extends to a bottom surface of the top electrode, an inside of the top electrode, or a top surface of the top electrode.
4. The bulk acoustic wave resonator according to any one of claims 1 to 3, characterized in that the resonance region further comprises a central region, the edge regions being disposed around the central region;
the spacing of the at least one cavity in the circumferential direction is less than a preset threshold.
5. The bulk acoustic wave resonator according to claim 4, wherein the at least one cavity comprises at least one first cavity;
the first cavity is disposed around the central region, and an orthographic projection of the first cavity on the substrate is a closed shape.
6. The bulk acoustic wave resonator according to claim 4, wherein the at least one cavity comprises at least one second cavity;
the second cavity is arranged around the central area, and an orthographic projection of the second cavity on the substrate is in a non-closed shape with an opening, and the distance of the opening is smaller than the preset threshold value.
7. The bulk acoustic wave resonator according to claim 5, wherein the at least one cavity comprises a plurality of third cavities;
the plurality of third cavities are arranged at intervals in the surrounding direction, and the interval distance between any two adjacent third cavities is smaller than the preset threshold value.
8. The bulk acoustic wave resonator according to claim 4, characterized in that the preset threshold is 50 μm.
9. The bulk acoustic wave resonator according to claim 1, characterized in that the length of the edge region in a direction towards the center of the resonance region is less than 3 μm.
10. The bulk acoustic wave resonator according to claim 1, wherein the cavity is filled with any one of air and a non-metallic material, the non-metallic material comprising silicon dioxide.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010828584.7A CN112003581A (en) | 2020-08-18 | 2020-08-18 | Bulk acoustic wave resonator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010828584.7A CN112003581A (en) | 2020-08-18 | 2020-08-18 | Bulk acoustic wave resonator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112003581A true CN112003581A (en) | 2020-11-27 |
Family
ID=73472644
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010828584.7A Pending CN112003581A (en) | 2020-08-18 | 2020-08-18 | Bulk acoustic wave resonator |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112003581A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113726308A (en) * | 2021-02-22 | 2021-11-30 | 武汉衍熙微器件有限公司 | Bulk acoustic wave resonant structure and method of manufacturing the same |
| WO2023061191A1 (en) * | 2021-10-15 | 2023-04-20 | 武汉衍熙微器件有限公司 | Bulk acoustic wave resonant structure and preparation method therefor, and acoustic wave device |
| CN116633310A (en) * | 2023-07-20 | 2023-08-22 | 迈感微电子(上海)有限公司 | Film bulk acoustic resonator and preparation method thereof |
| CN117375568A (en) * | 2023-12-07 | 2024-01-09 | 常州承芯半导体有限公司 | Bulk acoustic wave resonator device and method for forming bulk acoustic wave resonator device |
-
2020
- 2020-08-18 CN CN202010828584.7A patent/CN112003581A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113726308A (en) * | 2021-02-22 | 2021-11-30 | 武汉衍熙微器件有限公司 | Bulk acoustic wave resonant structure and method of manufacturing the same |
| WO2022174587A1 (en) * | 2021-02-22 | 2022-08-25 | 武汉衍熙微器件有限公司 | Bulk acoustic wave resonant structure and manufacturing method therefor |
| WO2023061191A1 (en) * | 2021-10-15 | 2023-04-20 | 武汉衍熙微器件有限公司 | Bulk acoustic wave resonant structure and preparation method therefor, and acoustic wave device |
| CN116633310A (en) * | 2023-07-20 | 2023-08-22 | 迈感微电子(上海)有限公司 | Film bulk acoustic resonator and preparation method thereof |
| CN116633310B (en) * | 2023-07-20 | 2023-11-03 | 迈感微电子(上海)有限公司 | Film bulk acoustic resonator and preparation method thereof |
| CN117375568A (en) * | 2023-12-07 | 2024-01-09 | 常州承芯半导体有限公司 | Bulk acoustic wave resonator device and method for forming bulk acoustic wave resonator device |
| CN117375568B (en) * | 2023-12-07 | 2024-03-12 | 常州承芯半导体有限公司 | Bulk acoustic wave resonator device and method for forming bulk acoustic wave resonator device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112003581A (en) | Bulk acoustic wave resonator | |
| KR102642910B1 (en) | Acoustic resonator and method of manufacturing thereof | |
| CN110324022B (en) | Resonator and preparation method thereof | |
| CN109831172B (en) | Method for preparing bulk acoustic wave resonator | |
| CN105048986A (en) | Acoustic resonator device with air-ring and temperature compensating layer | |
| CN104639087A (en) | Piezoelectric thin film resonator, filter and duplexer | |
| TWI772896B (en) | Transducer structure for an acoustic wave device | |
| CN111786644B (en) | Bulk acoustic wave resonator, method of manufacturing the same, filter, and radio frequency communication system | |
| WO2021042740A1 (en) | Bulk acoustic wave resonator and manufacturing method therefor, filter and electronic device | |
| CN110868182A (en) | Resonator and filter | |
| CN111010108A (en) | Bulk acoustic wave resonator with recess and air wing structure, filter and electronic device | |
| KR20180107852A (en) | Acoustic resonator and manufacturing method thereof | |
| JP2022507219A (en) | Bulk acoustic wave resonator and its manufacturing method, filter, radio frequency communication system | |
| JP2022507223A (en) | Bulk acoustic wave resonator and its manufacturing method, filter, radio frequency communication system | |
| KR20240028967A (en) | Bulk acoustic resonator and its manufacturing method, filter and electronic device | |
| CN213693649U (en) | Bulk acoustic wave resonator | |
| CN113556100B (en) | Bulk acoustic wave resonator | |
| JP2022507306A (en) | Bulk acoustic wave resonator and its manufacturing method, filter, radio frequency communication system | |
| CN111585537B (en) | Resonator and filter | |
| JP2022507221A (en) | Bulk acoustic wave resonator and its manufacturing method, filter, radio frequency communication system | |
| CN110868174A (en) | Acoustic resonator and filter | |
| JP2022507320A (en) | Bulk acoustic wave resonator and its manufacturing method, filter, radio frequency communication system | |
| CN112821878A (en) | Pseudo-mode suppression type radio frequency resonator structure | |
| CN114172483A (en) | Bulk acoustic wave resonator | |
| CN114172486A (en) | Bulk acoustic wave resonator |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |