CN114070234A - Bulk acoustic wave resonator, bulk acoustic wave resonator component, filter, and electronic device - Google Patents
Bulk acoustic wave resonator, bulk acoustic wave resonator component, filter, and electronic device Download PDFInfo
- Publication number
- CN114070234A CN114070234A CN202010779406.XA CN202010779406A CN114070234A CN 114070234 A CN114070234 A CN 114070234A CN 202010779406 A CN202010779406 A CN 202010779406A CN 114070234 A CN114070234 A CN 114070234A
- Authority
- CN
- China
- Prior art keywords
- electrode
- resonator
- acoustic impedance
- impedance layer
- bridge structure
- 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
- 239000000725 suspension Substances 0.000 claims abstract description 71
- 239000000758 substrate Substances 0.000 claims abstract description 30
- 239000000463 material Substances 0.000 claims description 49
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 43
- 235000012239 silicon dioxide Nutrition 0.000 claims description 22
- 239000013078 crystal Substances 0.000 claims description 20
- 239000000377 silicon dioxide Substances 0.000 claims description 19
- 230000001902 propagating effect Effects 0.000 claims description 13
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims description 11
- 229920005591 polysilicon Polymers 0.000 claims description 11
- 229910021417 amorphous silicon Inorganic materials 0.000 claims description 10
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 9
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 9
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 8
- 238000000034 method Methods 0.000 description 12
- 239000010408 film Substances 0.000 description 10
- 230000000694 effects Effects 0.000 description 7
- 238000005530 etching Methods 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- 235000019687 Lamb Nutrition 0.000 description 5
- 238000004891 communication Methods 0.000 description 5
- 239000011777 magnesium Substances 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 239000010936 titanium Substances 0.000 description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 4
- JMASRVWKEDWRBT-UHFFFAOYSA-N Gallium nitride Chemical compound [Ga]#N JMASRVWKEDWRBT-UHFFFAOYSA-N 0.000 description 4
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 229910052802 copper Inorganic materials 0.000 description 4
- 239000010949 copper Substances 0.000 description 4
- 239000007772 electrode material Substances 0.000 description 4
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 4
- 229910052737 gold Inorganic materials 0.000 description 4
- 239000010931 gold Substances 0.000 description 4
- 229910052749 magnesium Inorganic materials 0.000 description 4
- 239000010409 thin film Substances 0.000 description 4
- 229910052719 titanium Inorganic materials 0.000 description 4
- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 description 3
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 3
- 229910002601 GaN Inorganic materials 0.000 description 3
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 3
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 238000005229 chemical vapour deposition Methods 0.000 description 3
- 229910052804 chromium Inorganic materials 0.000 description 3
- 239000011651 chromium Substances 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 229910052741 iridium Inorganic materials 0.000 description 3
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 3
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 238000001451 molecular beam epitaxy Methods 0.000 description 3
- 229910052750 molybdenum Inorganic materials 0.000 description 3
- 239000011733 molybdenum Substances 0.000 description 3
- 229910052762 osmium Inorganic materials 0.000 description 3
- SYQBFIAQOQZEGI-UHFFFAOYSA-N osmium atom Chemical compound [Os] SYQBFIAQOQZEGI-UHFFFAOYSA-N 0.000 description 3
- 239000010453 quartz Substances 0.000 description 3
- 229910052707 ruthenium Inorganic materials 0.000 description 3
- 229910010271 silicon carbide Inorganic materials 0.000 description 3
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 3
- 229910052721 tungsten Inorganic materials 0.000 description 3
- 239000010937 tungsten Substances 0.000 description 3
- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 description 2
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 229910003460 diamond Inorganic materials 0.000 description 2
- 239000010432 diamond Substances 0.000 description 2
- 239000003989 dielectric material Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000005468 ion implantation Methods 0.000 description 2
- 238000004943 liquid phase epitaxy Methods 0.000 description 2
- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 2
- 238000000059 patterning Methods 0.000 description 2
- 238000005240 physical vapour deposition Methods 0.000 description 2
- 238000000623 plasma-assisted chemical vapour deposition Methods 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- UKDIAJWKFXFVFG-UHFFFAOYSA-N potassium;oxido(dioxo)niobium Chemical compound [K+].[O-][Nb](=O)=O UKDIAJWKFXFVFG-UHFFFAOYSA-N 0.000 description 2
- 229910052761 rare earth metal Inorganic materials 0.000 description 2
- 229910052594 sapphire Inorganic materials 0.000 description 2
- 239000010980 sapphire Substances 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- 230000002195 synergetic effect Effects 0.000 description 2
- 238000000427 thin-film deposition Methods 0.000 description 2
- PIGFYZPCRLYGLF-UHFFFAOYSA-N Aluminum nitride Chemical compound [Al]#N PIGFYZPCRLYGLF-UHFFFAOYSA-N 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- 229910052692 Dysprosium Inorganic materials 0.000 description 1
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 229910052693 Europium Inorganic materials 0.000 description 1
- 229910052688 Gadolinium Inorganic materials 0.000 description 1
- 229910052689 Holmium Inorganic materials 0.000 description 1
- 229910052765 Lutetium Inorganic materials 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 229910052773 Promethium Inorganic materials 0.000 description 1
- 229910052772 Samarium Inorganic materials 0.000 description 1
- 229910052771 Terbium Inorganic materials 0.000 description 1
- 229910052775 Thulium Inorganic materials 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
- 230000001154 acute effect Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005137 deposition process Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- KBQHZAAAGSGFKK-UHFFFAOYSA-N dysprosium atom Chemical compound [Dy] KBQHZAAAGSGFKK-UHFFFAOYSA-N 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- UYAHIZSMUZPPFV-UHFFFAOYSA-N erbium Chemical compound [Er] UYAHIZSMUZPPFV-UHFFFAOYSA-N 0.000 description 1
- OGPBJKLSAFTDLK-UHFFFAOYSA-N europium atom Chemical compound [Eu] OGPBJKLSAFTDLK-UHFFFAOYSA-N 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- UIWYJDYFSGRHKR-UHFFFAOYSA-N gadolinium atom Chemical compound [Gd] UIWYJDYFSGRHKR-UHFFFAOYSA-N 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- KJZYNXUDTRRSPN-UHFFFAOYSA-N holmium atom Chemical compound [Ho] KJZYNXUDTRRSPN-UHFFFAOYSA-N 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 239000013067 intermediate product Substances 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 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
- OHSVLFRHMCKCQY-UHFFFAOYSA-N lutetium atom Chemical compound [Lu] OHSVLFRHMCKCQY-UHFFFAOYSA-N 0.000 description 1
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- PUDIUYLPXJFUGB-UHFFFAOYSA-N praseodymium atom Chemical compound [Pr] PUDIUYLPXJFUGB-UHFFFAOYSA-N 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- VQMWBBYLQSCNPO-UHFFFAOYSA-N promethium atom Chemical compound [Pm] VQMWBBYLQSCNPO-UHFFFAOYSA-N 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- KZUNJOHGWZRPMI-UHFFFAOYSA-N samarium atom Chemical compound [Sm] KZUNJOHGWZRPMI-UHFFFAOYSA-N 0.000 description 1
- 229910052706 scandium Inorganic materials 0.000 description 1
- SIXSYDAISGFNSX-UHFFFAOYSA-N scandium atom Chemical compound [Sc] SIXSYDAISGFNSX-UHFFFAOYSA-N 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- GZCRRIHWUXGPOV-UHFFFAOYSA-N terbium atom Chemical compound [Tb] GZCRRIHWUXGPOV-UHFFFAOYSA-N 0.000 description 1
- FRNOGLGSGLTDKL-UHFFFAOYSA-N thulium atom Chemical compound [Tm] FRNOGLGSGLTDKL-UHFFFAOYSA-N 0.000 description 1
- NAWDYIZEMPQZHO-UHFFFAOYSA-N ytterbium Chemical compound [Yb] NAWDYIZEMPQZHO-UHFFFAOYSA-N 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 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
-
- 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
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
- H03H9/56—Monolithic crystal filters
- H03H9/564—Monolithic crystal filters implemented with thin-film techniques
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
The invention relates to a bulk acoustic wave resonator comprising: a substrate; an acoustic mirror; a bottom electrode; a top electrode; and a piezoelectric layer disposed between the bottom electrode and the top electrode, wherein: an acoustic impedance structure is arranged between the piezoelectric layer and the substrate; the acoustic impedance structure includes a first acoustic impedance layer and a second acoustic impedance layer disposed adjacent to each other in a lateral direction, the first acoustic impedance layer being different in acoustic impedance from the second acoustic impedance layer; the acoustic mirror is located between the first acoustic impedance layers in a lateral direction of the resonator, and the bottom electrode and/or the top electrode is provided with a suspension wing and/or a bridge structure. The invention also relates to a bulk acoustic wave resonator assembly, a filter and an electronic device.
Description
Technical Field
Embodiments of the present invention relate to the field of semiconductors, and in particular, to a bulk acoustic wave resonator, a filter having the resonator, a bulk acoustic wave resonator assembly, and an electronic device.
Background
With the development of 5G communication technology, the requirement on the communication frequency band is higher and higher. The traditional radio frequency filter is limited by structure and performance and cannot meet the requirement of high-frequency communication. As a novel MEMS device, a Film Bulk Acoustic Resonator (FBAR) has the advantages of small volume, light weight, low insertion loss, wide frequency band, high quality factor and the like, and is well suitable for the update of a wireless communication system, so that the FBAR technology becomes one of the research hotspots in the communication field.
The structural main body of the film bulk acoustic resonator is a sandwich structure consisting of an electrode, a piezoelectric film and an electrode, namely a layer of piezoelectric material is sandwiched between two metal electrode layers. By inputting a sinusoidal signal between the two electrodes, the FBAR converts the input electrical signal into mechanical resonance using the inverse piezoelectric effect, and converts the mechanical resonance into an electrical signal for output using the piezoelectric effect. The film bulk acoustic wave resonator mainly utilizes the longitudinal piezoelectric coefficient of the piezoelectric film to generate the piezoelectric effect, so the main working mode is the longitudinal wave mode in the thickness direction, namely, the acoustic wave of the bulk acoustic wave resonator is mainly in the film body of the resonator, and the main vibration direction is in the longitudinal direction. However, due to the existence of the boundary, there exists a lamb wave that is not perpendicular to the piezoelectric film layer at the boundary, and then the transverse lamb wave leaks from the transverse direction of the piezoelectric film layer, resulting in acoustic loss, so that the Q value of the resonator is reduced.
The prior art has proposed the use of laterally alternating high and low acoustic impedance layers to reduce lateral lamb wave leakage, but there is still a need to further reduce lateral lamb wave leakage.
Disclosure of Invention
The invention is provided for further reducing the leakage of the transverse lamb wave and improving the Q value of the bulk acoustic wave resonator.
According to an aspect of an embodiment of the present invention, there is provided a bulk acoustic wave resonator including:
a substrate;
an acoustic mirror;
a bottom electrode;
a top electrode; and
a piezoelectric layer disposed between the bottom electrode and the top electrode,
wherein:
an acoustic impedance structure is arranged between the piezoelectric layer and the substrate;
the acoustic impedance structure includes a first acoustic impedance layer and a second acoustic impedance layer disposed adjacent to each other in a lateral direction, the first acoustic impedance layer being different in acoustic impedance from the second acoustic impedance layer, the acoustic mirror being located between the first acoustic impedance layers in the lateral direction of the resonator; and is
The bottom electrode and/or the top electrode are provided with a cantilever and/or a bridge structure.
Embodiments of the present invention also relate to a bulk acoustic wave resonator assembly comprising at least two of the above resonators sharing a common substrate.
Embodiments of the invention also relate to a filter comprising a bulk acoustic wave resonator or resonator assembly as described above.
Embodiments of the invention also relate to an electronic device comprising a filter as described above or a resonator or an assembly as described above.
Drawings
These and other features and advantages of the various embodiments of the disclosed invention will be better understood from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate like parts throughout, and in which:
fig. 1 is a schematic bottom view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;
fig. 2A is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention, taken along the MOM' line in fig. 1, wherein the top electrode is provided with a suspended wing and bridge structure;
FIG. 2B is an enlarged partial schematic view of FIG. 2A schematically illustrating parameters associated with the overhang and bridge configuration of the top electrode;
fig. 2C is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention, taken along the MOM' line in fig. 1, in which a top electrode is provided with a suspended wing and bridge structure, and a portion of a non-electrode connection terminal of a bottom electrode is covered with a first acoustic impedance layer;
fig. 2D is a schematic sectional view of the bulk acoustic wave resonator according to an exemplary embodiment of the present invention, taken along the NON' line in fig. 1, in which the NON-electrode connection terminals of the bottom electrode and the top electrode are shown, and the NON-electrode connection terminal of the bottom electrode on the side where the release hole is not provided is covered with a portion of the first acoustic impedance layer;
fig. 3A is an enlarged partial cross-sectional view similar to fig. 2B, taken along the MOM' line in fig. 1, of a bulk acoustic wave resonator according to another exemplary embodiment of the invention, wherein the bottom electrode is provided with a suspended wing and a bridge structure, the bridge structure not being covered by the first acoustic impedance layer;
fig. 3B is a schematic cross-sectional view of a bulk acoustic wave resonator similar to that taken along line NON' in fig. 1, showing the NON-electrode connecting ends of the bottom and top electrodes, with the NON-electrode connecting end of the bottom electrode spaced from the first acoustic impedance layer, according to another exemplary embodiment of the present invention;
FIG. 4A is an enlarged, fragmentary, cross-sectional view, similar to that of FIG. 2B, of a bulk acoustic wave resonator, according to yet another exemplary embodiment of the present invention, taken along the MOM' line of FIG. 1;
fig. 4B is an enlarged partial cross-sectional view similar to fig. 2B, taken along the MOM' line in fig. 1, of a bulk acoustic wave resonator according to yet another exemplary embodiment of the present invention, in which there is a partial overlap of the bridge structure of the top electrode with the first acoustic impedance layer in the thickness direction;
fig. 4C is an enlarged partial cross-sectional view similar to fig. 2B, taken along the MOM' line in fig. 1, of a bulk acoustic wave resonator according to yet another exemplary embodiment of the present invention, in which there is a partial overlap of the bridge structure of the bottom electrode with the first acoustic impedance layer in the thickness direction;
fig. 5A is an enlarged, fragmentary, cross-sectional view, similar to fig. 2B, of a bulk acoustic wave resonator, according to another exemplary embodiment of the present invention, and taken along the NON' line in fig. 1, showing both the top and bottom electrodes provided with the cantilever;
fig. 5B is an enlarged, fragmentary, cross-sectional view, similar to fig. 2B, of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention, and taken along the NON' line in fig. 1, showing both the top and bottom electrodes provided with the overhang, the bottom electrode further provided with a bridge structure;
fig. 5C is a schematic partial cross-sectional view, similar to line NON' in fig. 1, of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention, showing the NON-electrode connecting end of the top electrode provided with a bridge structure and the NON-electrode connecting end of the bottom electrode provided with a suspension wing;
fig. 6A is an enlarged partial cross-sectional schematic view similar to fig. 2B, taken along the MOM' line in fig. 1, of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention, wherein the cantilever of the top electrode and the inner edge of the bridge structure are outside the inner edges of the bridge structure of the bottom electrode and the cantilever, respectively;
fig. 6B is an enlarged partial cross-sectional schematic view, similar to fig. 2B, of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention, taken along the MOM' line in fig. 1, wherein the cantilever of the top electrode and the inner edge of the bridge structure are inside the bridge structure of the bottom electrode and the inner edge of the cantilever, respectively;
FIG. 7 is a schematic cross-sectional view of a bulk acoustic wave resonator assembly according to an exemplary embodiment of the present invention;
FIGS. 8A-8L illustrate a fabrication process similar to that of FIG. 2A but with a partial enlargement of the structure shown in FIG. 4A;
fig. 9 is a schematic cross-sectional view of a bulk acoustic wave resonator according to still another exemplary embodiment of the present invention, similar to that taken along the MOM' line in fig. 1.
Detailed Description
The technical scheme of the invention is further specifically described by the following embodiments and the accompanying drawings. In the specification, the same or similar reference numerals denote the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the general inventive concept of the present invention and should not be construed as limiting the invention. Some, but not all embodiments of the invention are described. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.
First, the reference numerals in the drawings of the present invention are explained as follows:
1: a single crystal piezoelectric layer, which may be made of single crystal aluminum nitride, single crystal gallium nitride, single crystal lithium niobate, single crystal lead zirconate titanate, single crystal potassium niobate, single crystal quartz film, or single crystal lithium tantalate, and may further include an atomic ratio of rare earth element-doped materials of the above materials, for example, doped aluminum nitride, which contains at least one rare earth element, such as scandium (Sc), yttrium (Y), magnesium (Mg), titanium (Ti), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), and the like.
2: the bottom electrode is made of molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or their composite or their alloy.
3: the acoustic impedance layer, or the first acoustic impedance layer, may be made of aluminum nitride, silicon dioxide, silicon nitride, polysilicon, or amorphous silicon.
4: acoustic resistive layer two or a second acoustic resistive layer, also acting as a sacrificial layer. The second acoustic impedance layer may be made of silicon dioxide, doped silicon dioxide, polysilicon, amorphous silicon, or the like, but is different from the first acoustic impedance layer material, and the etchant of the second acoustic impedance layer is not easy to etch or does not etch the first acoustic impedance layer material.
5: the substrate can be selected from monocrystalline silicon, gallium nitride, gallium arsenide, sapphire, quartz, silicon carbide, diamond and the like.
5 a: the auxiliary substrate can be selected from monocrystalline silicon, gallium nitride, gallium arsenide, sapphire, quartz, silicon carbide, diamond and the like, and can also be a monocrystalline piezoelectric substrate of lithium niobate, lithium tantalate, potassium niobate and the like.
6: the top electrode can be made of the same material as the bottom electrode, and the material can be selected from molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or the composite of the above metals or the alloy thereof, and the like. The top and bottom electrode materials are typically the same, but may be different.
6 a: the first electrode connecting part (or the electrode leading-out part) can be manufactured simultaneously with the top electrode, and the material can be selected from molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or the compound of the metals or the alloy thereof.
7: and the second electrode connecting part (Bonding PAD, or bottom electrode electric connecting layer) can be made of copper, gold or a composite of the above metals or an alloy thereof.
8: the acoustic mirror can be a cavity, and a Bragg reflection layer and other equivalent forms can also be adopted. The embodiment of the invention shown uses a cavity.
9: and a release hole for etching the sacrificial layer to form a cavity.
9 a: an electrode opening or via, which can be made simultaneously with the relief hole, is used for electrically connecting the first electrode connection with the electrode connection end of the bottom electrode.
10: and (4) hanging wings.
13: a bridge structure.
Fig. 1 is a schematic bottom view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention. Fig. 2A is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention, taken along the MOM' line in fig. 1, showing an electrode lead-out region of a bottom electrode and an electrode lead-out region of a top electrode, with an electrode connection end of the bottom electrode covered by a portion of a first acoustic impedance layer, and a non-electrode connection end of the bottom electrode spaced apart from the first acoustic impedance layer in a lateral direction, in fig. 2A, the top electrode is provided with a suspended wing and bridge structure.
As shown in fig. 1 and 2A, the bulk acoustic wave resonator includes: a substrate 5; an acoustic mirror 8; a bottom electrode 2; a top electrode 6; and a single crystal piezoelectric layer 1 disposed between the bottom electrode and the top electrode. An acoustic impedance structure is arranged between the piezoelectric layer 1 and the substrate 5, and an acoustic mirror 8 is located between the acoustic impedance structures in the transverse direction of the resonator, said acoustic impedance structure comprising a first acoustic impedance layer 3 and a second acoustic impedance layer 4 arranged adjacent to each other in the transverse direction, more specifically, the acoustic mirror 8 is located between the first acoustic impedance layers 3 in the transverse direction of the resonator.
In fig. 2A, the top electrode 6 is provided with a suspension 10 and a bridge structure 13, whereas the bottom electrode 2 is not provided with a suspension and a bridge structure. As can be appreciated, the electrode may be provided with only the overhang or only the bridge structure, and in addition, the bottom electrode may also be provided with the overhang and/or the bridge structure, or both the top and the bottom electrode may be provided with the overhang and/or the bridge structure.
In the invention, the acoustic impedances of the first acoustic impedance layer 3 and the second acoustic impedance layer 4 are different, so that impedance mismatching is formed, continuous reflection is formed on sound waves, and a reflection structure for transverse sound waves is formed, so that transverse sound waves are prevented from leaking, energy is favorably locked in a resonator, and the Q value is improved. First acoustic impedance layer 3 and second acoustic impedance layer 4 are first acoustic reflection layer and second acoustic reflection layer, form the not matched layer of effectual acoustic impedance and can prevent revealing of transverse sound wave, can realize the suppression to the revealing of transverse wave through setting up the width of first acoustic impedance layer 3 and second acoustic impedance layer 4, thereby this structure is mainly can reflect the resonator to the transverse wave of revealing outside the resonator and promote the Q value.
If only the external acoustic reflection structure formed by the first acoustic impedance layer 3 and the second acoustic impedance layer 4 is formed, the transverse wave reflected by the first acoustic impedance layer 3 and the second acoustic impedance layer 4 to the inside of the resonator still has a part of energy leaked again from the boundary because there is no limitation of the boundary structure, so that the boundary structure needs to be further increased to effectively lock the part of energy inside the resonator. In the invention, by introducing the bridge structure and/or the suspension wing structure into the electrode, on one hand, a zero-impedance reflecting surface can be formed by virtue of an air gap layer formed between the electrode and the piezoelectric layer, and then the laminated structure in the vertical direction of the resonator is changed, so that transverse sound waves are effectively reflected back to the inside of the resonator at the interface, and on the other hand, the cantilever beam type free end structure formed by the electrode can generate secondary resonance under the excitation of the transverse waves, so that energy is bound at the free end of the electrode. Therefore, the bridge structure and/or the wing structure are introduced, and optionally, the position relationship between the bridge wing structure and the acoustic impedance layer is reasonably set, so that not only can the leakage of internal transverse waves be prevented, but also the energy reflected by the first acoustic impedance layer 3 and the second acoustic impedance layer 4 can be further locked in the resonator, and the leakage of the energy can be further effectively prevented. Through the mutual cooperation of the acoustic impedance structure and the suspension wing/bridge structure, the leakage of sound waves can be effectively prevented, and the Q value of the resonator is improved.
In the invention, the single-crystal piezoelectric material is utilized, and the crystal lattice of the single-crystal piezoelectric material has few defect points, so that the material loss is lower, the Q value of a resonator is higher, and the electromechanical coupling coefficient and the power capacity can be improved.
In a further embodiment, the widths of the portions of the first acoustic impedance layer 3 and the second acoustic impedance layer 4 in contact with the piezoelectric layer 1 are m λ3A/4 and n lambda4A/4, where m and n are both odd, e.g. 1,3, 5,7, etc.. lambda.3And λ4Respectively, the acoustic wave wavelengths that propagate in the lateral direction at the resonance frequency at the corresponding portions of the first acoustic impedance layer and the second acoustic impedance layer in contact with the piezoelectric layer. The resonance frequency is a certain frequency in a resonance interval of the resonator, and may be a series resonance frequency or a parallel resonance frequency of the resonator, or a certain frequency between the series resonance frequency and the parallel resonance frequency, or a certain frequency slightly lower than the series resonance frequency or slightly higher than the parallel resonance frequency. In the drawing, the width of the first acoustic impedance layer 3 is denoted by a, and the width of the second acoustic impedance layer 4 is denoted by B. The width is selected, so that effective acoustic impedance mismatching is favorably formed, transverse sound wave leakage is prevented, and the Q value of the resonator is further improved. m and n may be the same or different and are within the scope of the present invention.
The material forming the first acoustic impedance layer 3 comprises aluminum nitride, silicon dioxide, silicon nitride, polysilicon, amorphous silicon, and the material forming the second acoustic impedance layer 4 comprises silicon dioxide, doped silicon dioxide, polysilicon, amorphous silicon. The material of the first acoustic impedance layer 3 and the material of the second acoustic impedance layer 4 are different from each other. Alternatively, the material forming the first acoustic impedance layer 3 comprises silicon dioxide and the material forming the second acoustic impedance layer 4 comprises polysilicon. Alternatively, the material forming the first acoustic impedance layer 3 comprises silicon nitride or aluminum nitride, and the material forming the second acoustic impedance layer 4 comprises silicon dioxide or doped silicon dioxide. In the present invention, in order to increase the degree of acoustic mismatch at the junction of the first acoustic impedance layer 3 and the second acoustic impedance layer 4, the difference between the acoustic impedances of the two layers may be selected to be as large as possible.
As will be described later with reference to fig. 8A-8L, during the manufacture of the resonator, the second acoustic impedance layer simultaneously acts as a sacrificial layer, and therefore when the sacrificial layer is released, a suitable release etchant needs to be selected such that the etchant etches only the second acoustic impedance material and not or very little of the first acoustic impedance material.
As shown in fig. 2A, the end face of the non-electrode connection terminal (right end in 2A) of the bottom electrode 2 is spaced apart from the first acoustic impedance layer 3 in the acoustic impedance structure in the lateral direction, so that the acoustic wave is also totally reflected at the lateral interface between the non-electrode connection terminal of the bottom electrode and the air gap, thereby reducing the acoustic wave leakage. Based on the gap structure at the non-electrode connecting end, transverse sound wave leakage can be further prevented, and the Q value of the resonator is improved.
In an alternative embodiment, in one longitudinal section of the resonator through the electrode connection end of the bottom electrode 2 (e.g. in the sectional view shown in fig. 2A), the end face of the non-electrode connection end of the bottom electrode 2 is spaced apart from the acoustic impedance structure in the lateral direction by a distance C in the range of 0 μm-50 μm. The distance may be, for example, 5 μm, 7 μm, 30 μm, or the like, in addition to the end values.
In an embodiment such as that shown in fig. 2A, the bottom electrode 2 is surrounded by a continuous reflective layer or acoustic impedance structure formed by the first acoustic impedance layer 3 and the second acoustic impedance layer 4 on the side of the electrode connection end, and more specifically, covered by the first acoustic impedance layer 3, which is advantageous for improving the mechanical stability of the resonator and for easier conduction of the heat generated during operation of the resonator to the substrate through the electrode and the first acoustic impedance layer 3, thereby improving the power capacity of the resonator, and is advantageous for locking the energy inside the resonator as much as possible due to the reflective interface formed by the second acoustic impedance layer and the first acoustic impedance layer, although the energy may leak from the bottom electrode end face into the first acoustic impedance layer 3, thereby maintaining the resonator at a high Q value.
Although not shown, in an alternative embodiment, the end surface of the non-electrode connection end of the bottom electrode 2 and the end surface of the electrode connection end may be both spaced apart from the first acoustic impedance layer 3 in the lateral direction, so that the acoustic wave also forms total reflection at the lateral interface of the bottom electrode and the gap, thereby reducing the acoustic wave leakage and being capable of improving the Q value of the resonator. Compared with the structure shown in fig. 2A, since the electrode connection end is also provided with the gap, it is advantageous to further prevent the lateral sound wave from leaking, but since the bottom electrode is not in direct contact with the first acoustic impedance layer, the heat must be indirectly conducted to the first acoustic impedance layer and the substrate through the piezoelectric material, which may result in poor power capacity. Likewise, the end face of the electrode connection end may be spaced apart from the acoustic impedance structure in the lateral direction by a distance C or a value different from C.
Fig. 2B is an enlarged partial schematic view of fig. 2A, schematically illustrating parameters associated with the cantilever and bridge structure of the top electrode.
In fig. 2B, the non-electrode connection end of the bottom electrode 2 is in a non-suspended wing structure (in fig. 2B, the non-electrode connection end is free of suspended wings, that is, in a non-suspended wing structure). As shown in fig. 2B, the width of the bridge structure is d12a, alternatively, d12a ranges from 0-50 μm; the overlapping area of the non-electrode connection end of the bottom electrode and the bridge structure of the top electrode in the thickness direction of the resonator (or the lateral distance between the inner edge of the bridge structure and the end point of the corresponding non-electrode connection end) is d43a, the magnitude of which has a large influence on the resonator performance. d43a is smaller than d12a and d43a has a width in the range of 0-20 μm to help ensure that the non-electrode connecting end of the bottom electrode falls within the bridge structure projection of the top electrode, when the active area of the resonator is defined by the bridge structure of the top electrode and the inner edge of the suspension wing.
In fig. 2B, the lateral distance between the non-connecting side of the top electrode (the outer edge of the overhang of the top electrode in fig. 2B) and the first acoustic impedance layer 3 is d40a, and the lateral distance between the non-connecting side of the bottom electrode and the first acoustic impedance layer 3 is d 44B; the lateral distance d41a from the outer edge of the bridge structure of the top electrode to the first acoustic impedance layer 3. In an alternative embodiment, d40a is in the range of 0-50 μm; and/or d44b is in the range of 0-50 μm; and/or d41a is in the range of 0-50 μm.
In addition, d41a and d44b may also be negative. When d41a is negative and d44B is positive, the outer edge of the top electrode bridge structure spans the first acoustic impedance layer 3 while the first acoustic impedance layer 3 is spaced from the non-connected end of the bottom electrode, similar to that shown in FIG. 4B.
When d41a and d44b are both negative, the first acoustic impedance layer 3 covers the non-connection end of the bottom electrode, and meanwhile, in order to avoid parasitic capacitance formed between the bottom electrode part extending into the acoustic impedance layer and the connection edge of the top electrode, thereby reducing the electrical performance of the resonator (including Q value, electromechanical coupling coefficient, and the like), the inner end of the set bridge structure needs to cross the edge of the first acoustic impedance layer 3, and the outer end needs to cross the edge of the non-connection end of the bottom electrode, i.e., it is ensured that the absolute value of d41a is smaller than d12a, and the absolute value of d43a is also smaller than d12a, as shown in fig. 2C. In this case, it is advantageous to improve the mechanical stability of the resonator, and it is easier to conduct the heat generated during the operation of the resonator to the substrate through the electrodes and the first acoustic impedance layer 3, thereby improving the power capacity of the resonator, and at the same time, although the energy leaks from the end face of the bottom electrode to the first acoustic impedance layer 3, since there is a reflection interface formed by the second acoustic impedance layer and the first acoustic impedance layer, it is also possible to lock the energy inside the resonator as much as possible, and to maintain the resonator at a high Q value.
As shown in fig. 2B, the width of the top electrode cantilever structure is d11a, alternatively, d11a ranges from 0-50 μm; the outer edge of the cantilevered structure is inside the edge of the first acoustic impedance layer 3 and is laterally spaced from the first acoustic impedance layer 3 by d40a, optionally d40a is in the range of 0-50 μm, when the lateral distance between the inner edge of the cantilevered top electrode 6 and the first acoustic impedance layer 3 is the sum of the cantilevered widths d11a and d40 a. In addition, d40a may also be negative, similar to that shown in the subsequent fig. 4C, i.e. the outer edge of the suspended wing structure of the top electrode crosses the edge of the first acoustic impedance layer 3, when the lateral distance between the inner edge of the suspended wing of the top electrode 6 and the first acoustic impedance layer 3 is the absolute value of the suspended wing width d11a minus d40 a. It is desirable to arrange d11a and d40a so that the inner edge of the suspension structure is always inside the edge of the first acoustic impedance layer 3.
In an alternative embodiment, d11a, d12a, d40a, d41a, d43a may be an odd multiple of λ/4, λ being the wavelength of the acoustic wave propagating in the lateral direction at the resonant frequency from the stacked structure in the thickness direction of the corresponding region. In a specific example, the d11a section corresponds to the top electrode overhang portion, the d12a section corresponds to the top electrode bridge portion, the d40a and d43a sections correspond to the bottom electrode and piezoelectric layer portion, and the d41a section corresponds to the top electrode and piezoelectric layer portion.
Fig. 2D is a schematic sectional view of the bulk acoustic wave resonator according to an exemplary embodiment of the present invention, taken along the NON' line in fig. 1, in which the NON-electrode connection ends of the bottom electrode and the top electrode are shown, and the NON-electrode connection end of the bottom electrode 2 on the side where the release hole is not provided is covered with a portion of the first acoustic impedance layer 3, the width of the covered area being equal to the lateral distance D44b between the NON-connection side of the bottom electrode and the first acoustic impedance layer 3. On one hand, the structure is beneficial to improving the mechanical stability of the resonator, and the heat generated by the resonator during working is more easily conducted to the substrate through the electrode and the first acoustic impedance layer 3, so that the power capacity of the resonator is improved; on the other hand, in this structure, although energy leaks from the end face of the bottom electrode into the first acoustic impedance layer 3, since there is a reflection interface formed by the second acoustic impedance layer and the first acoustic impedance layer, it is advantageous to lock as much energy as possible in the resonator, and to maintain the resonator at a high Q value. In addition, in the cross section taken along the NON' line in fig. 1, the first acoustic impedance layer 3 may also be spaced apart from the bottom electrode NON-connecting side, so that the acoustic wave forms total reflection at the lateral interface of the bottom electrode and the gap, thereby reducing the acoustic wave leakage and being capable of improving the Q value of the resonator.
As shown in fig. 2D, the non-electrode connection end of the bottom electrode 2 is of a non-suspended wing structure, and a release hole 9 may be provided between the outer edge of the non-electrode connection end and the first acoustic impedance layer 3 in the lateral direction of the resonator.
In an alternative embodiment, d11a is in the range of 0-50 μm; and/or d40a is in the range of 0-50 μm; and/or d44b is in the range of 0-50 μm.
In an alternative embodiment, d11a, d40a, d44b may be an odd multiple of λ/4, λ being the wavelength of the acoustic wave propagating in the lateral direction at the resonant frequency from the stacked structure in the thickness direction of the corresponding region. In a specific example, the interval d11a corresponds to the top electrode overhanging part, the interval d40a corresponds to the bottom electrode and piezoelectric layer part, and the interval d44b corresponds to the first acoustic impedance layer, the bottom electrode and the piezoelectric layer part. Fig. 3A is an enlarged partial sectional view similar to fig. 2B, taken along the MOM' line in fig. 1, of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention, in which it is shown that the electrode connection end of the bottom electrode 2 is covered by a portion of the first acoustic impedance layer, the non-electrode connection end of the bottom electrode 2 being spaced apart from the first acoustic impedance layer 3 in the lateral direction, and in fig. 3A, the bottom electrode is provided with a suspension wing 10 and a bridge structure 13, and the first acoustic impedance layer 3 is not covered by the bridge structure.
In fig. 3A, the non-electrode connection end of the bottom electrode 2 is of a suspended wing structure, and the non-electrode connection end of the top electrode 6 is of a non-suspended wing structure. As shown in FIG. 3A, the bridge structure 13 has a width d12b, alternatively, d12b in the range of 0-50 μm; the overlapping area of the non-electrode connection end of the top electrode and the bridge structure of the bottom electrode in the thickness direction of the resonator (or the lateral distance between the inner edge of the bridge structure and the end point of the non-electrode connection end) is d43b, the magnitude of which has a large influence on the resonator performance. d43b is smaller than d12b and d43b has a width in the range of 0 μm-20 μm to ensure that the non-electrode connecting end of the top electrode falls within the bridge structure projection of the bottom electrode, when the active area of the resonator is defined by the bridge of the bottom electrode and the inner edge of the cantilever structure.
In FIG. 3A, the width of the wing structure is d11b, alternatively, d11b ranges from 0-50 μm; the lateral distance between the non-connecting edge of the bottom electrode (the outer edge of the bottom electrode suspension in fig. 3A) and the first acoustic impedance layer 3 is d40 b; the lateral distance d41b from the outer edge of the bridge structure of the bottom electrode to the first acoustic impedance layer 3. Since the first acoustic impedance layer 3 has a reflection effect on the transverse waves leaking out of the filter and its distance has an important effect on the reflection of waves and energy, the arrangement or selection of d40b, d41b has a large influence on the performance of the resonator. In an alternative embodiment, d40b is in the range of 0-50 μm; and/or d41b is in the range of 0-50 μm. Further, d41b may be a negative value. When d41b is negative, i.e. the first acoustic impedance layer 3 covers a part of the bottom electrode bridge structure, it is necessary to ensure that d12b is larger than d41b, i.e. the edge of the first acoustic impedance layer 3 falls into the bottom electrode bridge structure. In an alternative embodiment, d11b, d12b, d40b, d41b, d43b may be an odd multiple of λ/4, λ being the wavelength of the acoustic wave propagating in the lateral direction at the resonant frequency from the stacked structure in the thickness direction of the corresponding region. In a specific example, the section d11b corresponds to a bottom electrode overhang portion, the section d12b corresponds to a bottom electrode bridge portion, the sections d40b and d43b correspond to a top electrode and piezoelectric layer portion, and the section d41b corresponds to a bottom electrode and piezoelectric layer portion.
Fig. 3B is a schematic cross-sectional view of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention, similar to that taken along the NON' line in fig. 1, showing the NON-electrode connection end of the bottom electrode 2 and the top electrode 6, with the NON-electrode connection end of the bottom electrode 2 spaced apart from the first acoustic impedance layer. In fig. 3B, in the lateral direction, without the release holes 9 between the flap and the first acoustic impedance layer 3, the distance between the outer edge of the flap and the first acoustic impedance layer 3 is d 40B.
In fig. 3B, the lateral distance between the top electrode non-connecting side (the non-electrode connecting end in fig. 3B is not flap, i.e., is a non-flap structure) and the first acoustic impedance layer 3 is d44a on the side where the release hole 9 is not provided; the distance between the outer edge of the overhang of the bottom electrode and the non-electrode connection end of the top electrode is d49 b. Wherein d49b may be positive or negative. When d49b is negative, i.e. the non-connecting edge of the top electrode falls in the overhang projection of the bottom electrode, it is necessary to set the absolute value of d11b greater than d49b so that the active area of the resonator is defined by the inner edge of the overhang of the bottom electrode. In addition, d49b may be further configured to be larger than d40b so that the non-connecting side of the top electrode partially overlaps the first acoustic impedance layer 3.
As shown in fig. 3B, the non-electrode connection end of the top electrode 6 is of a non-suspended wing structure, and a release hole 9 may be provided between the outer edge of the non-electrode connection end and the first acoustic impedance layer 3 in the lateral direction of the resonator.
In an alternative embodiment, d40b is in the range of 0 μm to 50 μm; and/or d44a is in the range of 0 μm to 50 μm; and/or d49b is in the range of 0 μm to 20 μm.
In an alternative embodiment, d11b, d49b, d44a may be an odd multiple of λ/4, λ being the wavelength of the acoustic wave propagating in the lateral direction at the resonant frequency from the stacked structure in the thickness direction of the corresponding region. In a specific example, the section d11b corresponds to the bottom electrode overhanging part, the section d49b corresponds to the top electrode and piezoelectric layer part, and the section d44a corresponds to the piezoelectric layer part.
In the present invention, the width of the overhang and bridge structure on the top electrode may be the same as or different from the width of the overhang and bridge structure on the bottom electrode. For the suspension wing or bridge structure on the top electrode or the bottom electrode, the widths of the suspension wing or bridge structure corresponding to different sides of the same resonator polygon may be the same or different, and are within the protection scope of the present invention.
Fig. 4A is an enlarged partial cross-sectional schematic view similar to fig. 2B, taken along the MOM' line in fig. 1, of a bulk acoustic wave resonator according to yet another exemplary embodiment of the present invention, showing both the bottom electrode and the top electrode provided with a cantilever 10 and a bridge structure 13. In fig. 4A, the bridge structure of the electrode is spaced from the first acoustic impedance layer 3 in the lateral direction, i.e., d41a and d41b are both greater than 0 as shown in fig. 4A. In alternative embodiments, d41a, d41b may be an odd multiple of λ/4, λ being the wavelength of the acoustic wave propagating in the transverse direction at the resonant frequency from the stacked structure in the thickness direction of the corresponding region. In a specific example, the section d41a corresponds to the top electrode and piezoelectric layer portion, and the section d41b corresponds to the bottom electrode and piezoelectric layer portion.
It should be noted that, in the present invention, the same reference signs have the same or similar meanings, and the reference signs of the parameters explained or shown with reference to the figures have the same or similar meanings as the foregoing descriptions when the reference signs are shown in other figures, and accordingly, the descriptions of the parameters also apply to the descriptions of the parameters in the corresponding embodiments, and are not repeated herein.
Fig. 4B is an enlarged partial cross-sectional view similar to fig. 2B, taken along the MOM' line in fig. 1, of a bulk acoustic wave resonator according to yet another exemplary embodiment of the present invention, showing that both the bottom electrode and the top electrode are provided with a suspended wing and bridge structure, wherein there is a partial overlap of the bridge structure of the top electrode 6 with the first acoustic impedance layer 3 in the thickness direction. As shown in fig. 4B, the outer edge of the bridge structure of the top electrode is outside the boundary of the first acoustic impedance layer 3 in the lateral direction of the resonator. The width of the overlap corresponds to d41 a.
In fig. 4B, the suspension wings and the bridge structure and the first and second acoustic impedance layers in the figure are both for enhancing the reflection of the transverse wave, so in order to achieve a synergistic effect of the suspension wings, the bridge structure and the acoustic impedance layers on the reflection of the transverse wave, the boundary of the first acoustic impedance layer 3 and the area of the bridge structure of the top electrode in fig. 4B are partially overlapped. In an alternative embodiment, d41a, d40b are odd multiples of λ/4, λ being the acoustic wavelength propagating in the transverse direction at the resonant frequency of the stacked structure at each distance from the thickness direction of the corresponding region. In a specific example, the interval d41a corresponds to the piezoelectric layer and the first acoustic impedance layer portion, and the interval d40b corresponds to the piezoelectric layer portion.
Fig. 4C is an enlarged partial cross-sectional view similar to fig. 2B, taken along the MOM' line in fig. 1, of a bulk acoustic wave resonator according to yet another exemplary embodiment of the present invention, showing that both the bottom electrode and the top electrode are provided with a suspended wing and bridge structure, wherein there is a partial overlap of the bridge structure of the bottom electrode with the first acoustic impedance layer in the thickness direction. As shown in fig. 4C, the outer edge of the bridge structure of the bottom electrode is outside the boundary of the first acoustic impedance layer 3 in the lateral direction of the resonator, i.e. the first acoustic impedance layer 3 covers a part of the bridge structure of the bottom electrode. The lateral distances of the overhang of the top electrode and the overhang of the bottom electrode from the first acoustic impedance layer 3 are d40a and d40b, respectively, and the lateral distances of the bridge structure of the top electrode and the bridge structure of the bottom electrode from the first acoustic impedance layer 3 are d41a and d41b, respectively. By adjusting the size of d41b, the actual suspension width of the bottom electrode bridge (the difference between d12b and d41 b) can be changed, and the reflection characteristic of the bridge structure to the transverse wave is further changed, so that the effect that the reflection of the transverse wave is synergistically enhanced by the suspension wing/bridge structure and the acoustic impedance layer is realized. In an alternative embodiment, d41b, d12b-d41b are odd multiples of λ/4, λ being the wavelength of the acoustic wave propagating in the transverse direction at the resonant frequency of the stacked structure at each distance from the thickness direction of the corresponding region. In a specific example, the interval d41b corresponds to the bottom electrode bridge structure portion and the first acoustic impedance layer portion, and the interval d12b-d41b corresponds to the bottom electrode bridge structure portion.
The structures shown in fig. 4B and 4C may also be combined into one structure, where the edge of the first acoustic impedance layer below the top electrode connecting edge falls into the projection of the top electrode connecting edge bridge structure, and the edge of the first acoustic impedance layer below the bottom electrode connecting edge falls into the projection of the bottom electrode connecting edge bridge structure.
Fig. 5A is an enlarged partial cross-sectional view similar to fig. 2B taken along the NON' line in fig. 1 of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention, showing both the top and bottom electrode NON-connecting sides provided with a cantilever. As shown in fig. 5A, the inner and outer edges of the overhang of the top and bottom electrodes are flush in the thickness direction, i.e., the upper and lower overhang widths are the same.
Fig. 5B is an enlarged partial cross-sectional schematic view, similar to fig. 2B, of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention, showing the top electrode non-connecting side provided with a suspension wing and the bottom electrode non-connecting side provided with a bridge structure, and similar to the MON line in fig. 1. In fig. 5B it can be seen that there is a region of overlap of the bridge structure of the bottom electrode with the first acoustic impedance layer 3, the lateral width of which corresponds to d 41B. By optimally setting the widths of d41b and d12b, the effect of synergistic enhancement of the reflection of the transverse wave by the bridge structure and the acoustic impedance layer can be achieved. In an alternative embodiment, d41b, d12b-d41b are odd multiples of λ/4, λ being the wavelength of the acoustic wave propagating in the transverse direction at the resonant frequency of the stacked structure at each distance from the thickness direction of the corresponding region. In a specific example, the interval d41b corresponds to the bottom electrode bridge structure portion and the first acoustic impedance layer portion, and the interval d12b-d41b corresponds to the bottom electrode bridge structure portion. Meanwhile, compared with the structure shown in fig. 5A, the structure shown in fig. 5B is advantageous in that the mechanical stability of the resonator is improved, and it is easier to conduct the heat generated when the resonator operates to the substrate through the electrodes and the first acoustic impedance layer 3, thereby improving the power capacity of the resonator. The invention is not limited thereto and the first acoustic impedance layer 3 may also not overlap the bridge structure of the bottom electrode but still cover the bottom electrode end, or the first acoustic impedance layer 3 may also be arranged spaced apart from the bottom electrode.
Fig. 5C is an enlarged partial cross-sectional view similar to fig. 2B, taken along the NON' line in fig. 1, of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention, showing the top electrode NON-connecting side provided with a bridge structure and the bottom electrode NON-connecting side provided with a cantilever structure. As shown in fig. 5C, the edge of the top electrode bridge structure is inside the edge of the first acoustic impedance layer 3, but the present invention is not limited thereto, and the edge of the top electrode bridge structure may cross the edge of the first acoustic impedance layer 3 so that the top electrode bridge structure is partially overlapped with the first acoustic impedance layer 3.
In the example shown in fig. 5A-5C, the width of the overhang on the top electrode and the overhang on the bottom electrode may be the same or different. For the suspended wing and bridge structures on the top electrode or the bottom electrode, the widths of the suspended wing and bridge structures corresponding to different sides of the same resonator polygon can be the same or different.
Both the position and the width variation of the boundary structure of the resonator have a large influence on the propagation and reflection of the transverse wave. Taking the mutual position relationship of the suspension wings and/or the bridge structures on the top electrode and the bottom electrode as an example, when the suspension wings and/or the bridge structures are overlapped with each other (for example, as shown in fig. 5A, the suspension wings are flush in the thickness direction), the interval laminated structure change caused by the suspension wings and the bridge structures is only one type, that is, the top electrode, the bottom electrode and the piezoelectric layer laminated structure is arranged on the inner side of the inner edge of the suspension wing structure, and the piezoelectric layer is arranged on the outer side of the inner edge of the suspension wing structure, so that an acoustic impedance mismatched interface is generated on the inner edges of the upper and lower suspension wing structures, and the reflection or inhibition of the transverse wave can be generated only once. However, when the position of the suspension wings and the bridge structure is different between the top electrode and the bottom electrode, for example, Δ d1 and Δ d5 in fig. 6A are not equal to zero, the Q value of the resonator is increased. Corresponding to fig. 5A, when the upper and lower sides of the suspension wing structure are the suspension wing structures, that is, the inner edges of the suspension wing structures of the upper and lower electrodes are not aligned, for example, the inner edge of the suspension wing structure of the top electrode may be on the inner side of the inner edge of the suspension wing structure of the bottom electrode, at this time, there are at least two kinds of laminated structure changes from the inner side to the outer side of the resonator, that is, the laminated structure of the top electrode, the bottom electrode and the piezoelectric layer is on the inner side of the inner edge of the suspension wing structure of the top electrode, the laminated structure of the piezoelectric layer and the bottom electrode is on the outer side of the inner edge of the suspension wing structure of the bottom electrode, and thus two impedance mismatched interfaces are generated, and the Q value of the resonator can be further enhanced.
Fig. 6A is an enlarged partial cross-sectional view similar to fig. 2B, taken along the MOM' line in fig. 1, of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention, showing both the top electrode and the bottom electrode provided with a cantilever and a bridge structure, wherein the inner edges of the cantilever and the bridge structure of the top electrode are outside the inner edges of the bridge structure and the cantilever of the bottom electrode, respectively.
Fig. 6B is an enlarged partial cross-sectional view similar to fig. 2B, taken along the MOM' line in fig. 1, of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention, showing both the top electrode and the bottom electrode provided with a cantilever and a bridge structure, wherein the inner edges of the cantilever and the bridge structure of the top electrode are inside the inner edges of the bridge structure of the bottom electrode and the cantilever, respectively.
More specifically, as shown in fig. 6A and 6B, the lateral distance or spacing between the inner edges of the overhangs of the top electrode and the inner edges of the bridge structure of the bottom electrode is Δ d1, and the lateral distance or spacing between the inner edges of the overhangs of the bottom electrode and the inner edges of the bridge structure of the top electrode is Δ d 5.
The magnitude of Δ d1 and Δ d5 values have a large impact on the performance of the resonator. In one embodiment of the invention, Δ d1 is in the range of 0-20 μm; and/or Δ d5 in the range of 0-20 μm. Furthermore, it is necessary to ensure that d12B is greater than Δ d1 (left side) in fig. 6A and d12a is greater than Δ d5 (right side) in fig. 6B, i.e., when the inner edge of the suspension wing structure is outside the inner edge of the other side bridge structure, it is necessary to ensure that the inner edge of the suspension wing structure does not exceed the outer edge of the other side bridge structure, in other words, it is necessary to ensure that the inner edge of the suspension wing structure falls within the projection of the other side bridge structure. Alternatively, the inner edge of the suspension wing structure is inside the inner edge of the other side bridge structure, as shown in the right-hand case of fig. 6A and the left-hand case of fig. 6B.
Taking the left structure as an example as shown in fig. 6A, the interval laminated structure caused by the suspension wing and the bridge structure changes three times, that is, the top electrode, the bottom electrode and the piezoelectric layer laminated structure are arranged on the inner edge of the bridge structure, the top electrode and the piezoelectric layer laminated structure are arranged from the outer side of the inner edge of the bridge structure to the inner side of the inner edge of the suspension wing structure, the piezoelectric layer is arranged from the outer side of the inner edge of the suspension wing structure to the inner side of the outer edge of the bridge structure, and the bottom electrode and the piezoelectric layer laminated structure are arranged on the outer side of the outer edge of the bridge structure, so that three mismatched acoustic impedance interfaces are generated, thereby being beneficial to the generation of multiple reflections of transverse waves on the impedance ratio matched interfaces, and the Q value of the resonator can be greatly improved by reasonably setting the widths of the intervals. In an alternative embodiment, Δ d1, d12b- Δ d1, d41b are odd multiples of λ/4, λ being the wavelength of the acoustic wave propagating laterally at the resonant frequency from the stacked structure in the thickness direction of the corresponding region. The structure on the right side of fig. 6A and the structure in fig. 6B can also be optimized using similar analysis methods. Figure 7 is a cross-sectional schematic view of a bulk acoustic wave resonator assembly according to an exemplary embodiment of the present invention. Two bulk acoustic wave resonators sharing the same substrate 5 are shown in figure 7. In fig. 7, the number of resonators may be more. In addition, in the embodiment shown in fig. 7, the top electrode and the bottom electrode of both resonators are provided with a suspension wing and bridge structure, but the present invention is not limited thereto, and the resonator in the assembly may be a resonator corresponding to any one of the structures shown in fig. 1-6B.
In the present invention, the first acoustic impedance layer 3 and the second acoustic impedance layer 4 may together constitute an acoustic impedance structure. However, the present invention is not limited thereto, in other words, the arrangement of the acoustic impedance layer is not limited thereto. It may be a multilayer structure including a first acoustic resistive layer and a second acoustic resistive layer, or a first acoustic resistive layer, a second acoustic resistive layer, and a first acoustic resistive layer, or a combination thereof, which are adjacently arranged in order in the lateral direction.
In a further embodiment, two resonators are adjacent in the lateral direction and have a first acoustic impedance structure and a second acoustic impedance structure, respectively, which share at least one layer of the first acoustic impedance layer 3 or at least one layer of the second acoustic impedance layer 4.
In one embodiment, three acoustic impedance layers, a first acoustic impedance layer, a second acoustic impedance layer, and a first acoustic impedance layer, are included between the acoustic mirrors of the two resonators. The two resonators share at least the second acoustic impedance layer 4 located at the center.
In one embodiment, five acoustic impedance layers, a first acoustic impedance layer, a second acoustic impedance layer, and a first acoustic impedance layer, are included between the acoustic mirrors of the two resonators. The two resonators share at least the first acoustic impedance layer 3 located in the middle. For a single resonator, the acoustic impedance structure surrounding the acoustic mirror 8 includes a first acoustic impedance layer 3, a second acoustic impedance layer 4, and a first acoustic impedance layer 3 arranged in this order from the inside to the outside.
The connection method of the adjacent resonators is not limited to the above, and the adjacent resonators may not be electrically connected to each other, but a plurality of acoustic impedance layers may be present between the adjacent resonators. In addition, only one acoustic impedance layer (first acoustic impedance layer) may be present between adjacent resonators. And more first acoustic impedance layer 3 and second acoustic impedance layer 4 can form more reflecting interfaces, further reduce the leakage of sound waves, and increase the Q value of the resonator. In addition, by selecting the number and/or width of the first acoustic impedance layer and the second acoustic impedance layer, the pattern specific gravity of the first acoustic impedance layer 3 and the second acoustic impedance layer 4 can be made more uniform, and a film layer with a flat surface can be formed more easily by a CMP (chemical mechanical polishing) process.
In one embodiment of the present invention, as shown in fig. 2A, the angle α formed between the face of the outer side face of the first acoustic impedance layer 3 and the bottom face of the piezoelectric layer may be selected to be in the range of 100 ° to 160 °, specifically, 100 °, 120 °, 160 °, and the like. This angle is chosen to facilitate filling of the second acoustic impedance layer 4 after patterning of the first acoustic impedance layer 3.
In one embodiment of the present invention, as shown in fig. 2A, the angle β formed between the outside of the end face of the bottom electrode 2 and the bottom surface of the piezoelectric layer 1 may be selected in the range of 90 ° to 160 °, specifically, 90 °, 100 °, 120 °, 160 °, or the like. The angle is chosen to facilitate filling of the first and second acoustic impedance layers 3, 4.
Fig. 9 is a schematic cross-sectional view of a bulk acoustic wave resonator similar to that taken along the MOM' line in fig. 1, showing an electrode lead-out region of a bottom electrode and an electrode lead-out region of a top electrode, with an electrode connection end of the bottom electrode covered by a portion of a first acoustic impedance layer, with a non-electrode connection end of the bottom electrode spaced apart from the first acoustic impedance layer in a lateral direction, in fig. 9, the top and bottom electrodes are each provided with a suspended wing and bridge structure, and in fig. 2A, the angle α is an obtuse angle, while in fig. 9, the angle α is an acute angle, according to an exemplary embodiment of the present invention. In the embodiment of the present invention, as shown in fig. 9, the angle α formed between the face of the outer side face of the first acoustic impedance layer 3 and the bottom face of the piezoelectric layer may be selected to be in the range of 20 ° to 80 °, specifically, 20 °, 60 °, 80 °, or the like.
For example, as shown in fig. 2A, the piezoelectric layer 1 is provided with a bottom electrode via hole 9a (see fig. 8I described later), and the electrode lead-out portion 6a is electrically connected to the electrode connection end of the bottom electrode 2 through the via hole 9 a. As shown in fig. 8J and 8K to be described later, the electrode lead-out portion 6a is formed of the same material as the top electrode 6 and has a lead-out portion arranged in the same layer as the top electrode. It is not excluded that the electrode lead-out portion 6a may be formed separately of other materials than the top electrode 6.
A process for manufacturing a single crystal piezoelectric thin film bulk acoustic resonator similar to that shown in fig. 2A (but the top electrode and the bottom electrode are provided with both the suspended wing and the bridge structure (a detailed enlarged view corresponds to fig. 4A)) is exemplarily described below with reference to fig. 8A to 8L.
As shown in fig. 8A, a single crystal piezoelectric thin film layer (i.e., a single crystal piezoelectric layer) 1, such as single crystal aluminum nitride (AlN), gallium nitride (GaN), is deposited on the surface of a substrate 5a (e.g., silicon carbide) by a deposition process including, but not limited to, MOCVD (metal organic chemical vapor deposition), MBE (molecular beam epitaxy), CBE (chemical molecular beam epitaxy), LPE (liquid phase epitaxy), etc.; or forming a boundary layer on the surface of an auxiliary substrate Aux1 (such as a lithium niobate or lithium tantalate substrate) by ion implantation, and forming the piezoelectric thin film layer 1 above the boundary layer, wherein the material of the piezoelectric thin film layer 1 is the same as that of the substrate 5 a. The upper surface of the piezoelectric layer 1 is bonded to the substrate 5 a.
As shown in fig. 8B, a sacrificial layer of a bottom electrode suspension wing and bridge structure is prepared on the piezoelectric layer, and the material of the sacrificial layer may be a dielectric material such as silicon nitride, silicon oxide, etc., and the sacrificial layer structure 14 is obtained by patterning through an etching process.
As shown in fig. 8C, a bottom electrode layer is deposited on the single crystal piezoelectric layer by a thin film deposition process such as CVD (chemical vapor deposition), PVD (physical vapor deposition), PECVD (plasma enhanced chemical vapor deposition), evaporation, sputtering, and the like, and then a bottom electrode 2 is obtained by an etching process.
As shown in fig. 8D, a layer of the first acoustic impedance material, which may be aluminum nitride, silicon dioxide, silicon nitride, polysilicon, amorphous silicon, etc., is deposited on the surface of the piezoelectric layer 1 and the bottom electrode 2 of the structure shown in fig. 8C and patterned to form the first acoustic impedance layer 3.
As shown in fig. 8E, a second acoustic impedance material is deposited on the surfaces of the piezoelectric layer 1, the first acoustic impedance layer 3, and the bottom electrode 2 of the resulting structure of fig. 8D, so that the second acoustic impedance material fills the gaps between the first acoustic impedance layer 3 (the gaps correspond to the acoustic mirror cavities), and the material of the second acoustic impedance layer may be silicon dioxide, doped silicon dioxide, polysilicon, amorphous silicon, etc., but is different from the material of the first acoustic impedance layer.
As shown in fig. 8F, the second acoustic impedance material is polished by a CMP (chemical mechanical polishing) method until the first acoustic impedance layer 3 is exposed, the second acoustic impedance material located outside the first acoustic impedance layer 3 constitutes the second acoustic impedance layer 4, and the second acoustic impedance material located between the first acoustic impedance layers 3 constitutes the sacrificial layer. In other words, in the present embodiment, the second acoustic impedance material is also a sacrificial material.
As shown in fig. 8G, the substrate 5 is bonded (bonding) on the lower sides of the first acoustic impedance layer 3 and the second acoustic impedance layer 4. Optionally, the surface of the substrate 5 may further have an auxiliary bonding layer (not shown), such as silicon dioxide, silicon nitride, or the like.
As shown in fig. 8H, the substrate 5a is removed by grinding, etching process or ion implantation layer separation method to expose the upper surface of the piezoelectric layer 1, and optionally, the separation interface is subjected to CMP processing to make the surface smooth and have low roughness.
As shown in fig. 8I, a through hole 9a is etched in the piezoelectric layer 1 by a process of photolithography and etching, and at the same time, a sacrificial layer release hole (not shown) is etched in the piezoelectric layer 1, the through hole being directly connected to the electrode connection terminal of the bottom electrode, or the through hole being directly connected to the acoustic mirror cavity or directly connected to the second acoustic impedance material, i.e., the sacrificial layer, located in the acoustic mirror cavity.
As shown in fig. 8J, a sacrificial layer of the top electrode suspension wing and the bridge structure is prepared on the piezoelectric layer, and the material of the sacrificial layer may be a dielectric material such as silicon nitride, silicon oxide, etc., and is patterned by an etching process.
As shown in fig. 8K, a layer of electrode material for the top electrode 6 is deposited covering the top surface of the piezoelectric layer and into the via 9a and the release hole, and then the layer of electrode material is etched to remove the electrode material in the release hole and patterned to form the top electrode 6.
As shown in fig. 8L, a conductive material is deposited through a process of thin film deposition and then patterned to form an electrode connection portion (bonding pad) or an electrode connection layer 7 including a top electrode connection layer and a bottom electrode connection layer.
Thereafter, an etchant is introduced through the release holes to release the second acoustic resistance layer material or the sacrificial layer inside the acoustic mirror cavity 8, resulting in a structure similar to that of fig. 2A but in which the top electrode and the bottom electrode are provided with both the suspension wings and the bridge structure (a detailed enlarged view corresponds to fig. 4A).
In the above-described manufacturing process, the first acoustic impedance layer 3 is first manufactured, and then the second acoustic impedance layer 4 is manufactured, so that the angle α formed between the surface of the outer side surface of the first acoustic impedance layer 3 and the bottom surface of the piezoelectric layer is in the range of 100 ° to 160 °. It is also possible to first manufacture the second acoustic resistive layer 4 and then the first acoustic resistive layer 3. The angle between the outside of the end face of the first acoustic impedance layer 3 and the bottom face of the piezoelectric layer may be different from that shown in fig. 2A depending on the manufacturing process.
In the present invention, the numerical ranges mentioned may be, besides the end points, the median values between the end points or other values, and are within the protection scope of the present invention.
In the present invention, the upper and lower are with respect to the bottom surface of the base of the resonator, and with respect to one component, the side thereof close to the bottom surface is the lower side, and the side thereof far from the bottom surface is the upper side.
In the present invention, the inner and outer are in terms of the transverse direction or the radial direction with respect to the center of the effective area of the resonator (the overlapping area of the piezoelectric layer, the top electrode, the bottom electrode, and the acoustic mirror in the thickness direction of the resonator constitutes the effective area), the side or end of a component close to the center is the inner side or the inner end, and the side or end of the component away from the center is the outer side or the outer end. For a reference position, being inside of the position means being between the position and the center (the center of the resonator effective area) in the lateral or radial direction, and being outside of the position means being farther from the center (the center of the resonator effective area) than the position in the lateral or radial direction.
It should be noted that in fig. 1, the first acoustic impedance layer and the second acoustic impedance layer are both formed in a ring shape around the acoustic mirror of the resonator, but it is also possible to embed the second acoustic impedance layer at a local position of the first acoustic impedance layer, and this is within the scope of the present invention.
In the present invention, the material of the piezoelectric layer may also be a non-single crystal material.
As can be appreciated by those skilled in the art, the bulk acoustic wave resonator according to the present invention may be used to form a filter or other semiconductor device.
Based on the above, the invention provides the following technical scheme:
1. a bulk acoustic wave resonator comprising:
a substrate;
an acoustic mirror;
a bottom electrode;
a top electrode; and
a piezoelectric layer disposed between the bottom electrode and the top electrode,
wherein:
an acoustic impedance structure is arranged between the piezoelectric layer and the substrate;
the acoustic impedance structure includes a first acoustic impedance layer and a second acoustic impedance layer disposed adjacent to each other in a lateral direction, the first acoustic impedance layer being different in acoustic impedance from the second acoustic impedance layer, the acoustic mirror being located between the first acoustic impedance layers in the lateral direction of the resonator; and is
The bottom electrode and/or the top electrode are provided with a cantilever and/or a bridge structure.
2. The resonator of claim 1, wherein:
the non-electrode connecting end of the bottom electrode and/or the top electrode is/are provided with a suspension wing, and in the transverse direction of the resonator, a first distance exists between the outer edge of the suspension wing and the corresponding first acoustic impedance layer in the transverse direction; or the non-electrode connecting end of the bottom electrode and/or the top electrode is of a non-suspended wing structure, and a third distance exists between the outer edge of the non-electrode connecting end and the corresponding first acoustic impedance layer in the transverse direction of the resonator.
3. The resonator of claim 2, wherein:
the first distance is in the range of 0-50 μm; and/or
The third distance is in the range of 0-50 μm.
4. The resonator of claim 2, wherein:
the outer edge of the overhang wing of the top electrode is outside the boundary of the first acoustic impedance layer on one side of the electrode connection end of the bottom electrode in the transverse direction of the resonator; or
The outer edge of the overhang wing of the top electrode is inside the boundary of the first acoustic impedance layer on the side of the electrode connection end of the bottom electrode in the lateral direction of the resonator; or
The non-electrode connecting end of the top electrode is of a non-suspension wing structure, the non-electrode connecting portion of the bottom electrode comprises a suspension wing, and in the transverse direction of the resonator, the edge of the non-electrode connecting end of the top electrode is located on the outer side of the inner end of the suspension wing of the bottom electrode.
5. The resonator of claim 2, wherein:
the first distance is λ1Odd multiples of/4, λ1The first distance corresponds to the wavelength of an acoustic wave propagating in the lateral direction at the resonance frequency of the laminated structure in the thickness direction of the region.
6. The resonator of claim 2, wherein:
the width of the suspension wings in the lateral direction of the resonator is in the range of 0-50 μm.
7. The resonator of claim 2, wherein:
and the non-electrode connecting end of only the top electrode or only the bottom electrode in the bottom electrode and the top electrode is provided with a suspension wing.
8. The resonator of any of claims 1-7, wherein:
the electrode connecting end and/or the non-electrode connecting end of the bottom electrode and/or the top electrode are/is provided with a bridge structure; and is
In a lateral direction of the resonator, an outer edge of the bridge structure is present at a fifth distance to the corresponding first acoustic impedance layer.
9. The resonator of claim 8, wherein:
the fifth distance is in the range of 0-50 μm.
10. The resonator of claim 8, wherein:
the outer edge of the bridge structure is outside the boundary of the first acoustic impedance layer on the side of the electrode connection end of the bottom electrode in the lateral direction of the resonator.
11. The resonator of claim 8, wherein:
a fifth distance λ2Odd multiples of/4, λ2The fifth distance corresponds to the wavelength of an acoustic wave propagating in the lateral direction at the resonance frequency of the laminated structure in the thickness direction of the region.
12. The resonator of claim 8, wherein:
the width of the bridge structure is in the range of 0-50 μm.
13. The resonator of any of claims 8-12, wherein:
the electrode connecting end and/or the non-electrode connecting end of one of the top electrode and the bottom electrode is provided with a bridge structure, and the non-electrode connecting end of the other of the top electrode and the bottom electrode is provided with a suspension wing or a bridge structure.
14. The resonator of claim 13, wherein:
the top electrode and the bottom electrode are both provided with a suspension wing and a bridge structure.
15. The resonator of claim 13, wherein:
the inner edge of the cantilever of one of the top and bottom electrodes is aligned with the inner edge of the bridge structure or the cantilever structure of the other of the top and bottom electrodes in the thickness direction of the resonator.
16. The resonator of claim 13, wherein:
the inner edge of the cantilever of one of the top and bottom electrodes is offset in the lateral direction from the inner edge of the corresponding bridge structure or cantilever structure of the other of the top and bottom electrodes.
17. The resonator of claim 16, wherein:
the inner edge of the cantilever of one of the top and bottom electrodes is spaced from the inner edge of the corresponding bridge structure or cantilever structure of the other of the top and bottom electrodes by a first distance in the lateral direction.
18. The resonator of claim 17, wherein:
the first interval is in the range of 0-50 μm.
19. The resonator of claim 8, wherein:
the electrode connecting end of the top electrode is provided with a bridge structure, the first acoustic impedance layer covers a part of the non-electrode connecting end of the bottom electrode, in the transverse direction, the boundary of the first acoustic impedance layer is positioned on the inner side of the edge of the non-electrode connecting end of the bottom electrode, the inner side of the bridge structure of the top electrode is positioned on the inner side of the boundary of the first acoustic impedance layer, and the outer side of the bridge structure of the top electrode is positioned on the outer side of the edge of the non-electrode connecting end of the bottom electrode; or
The non-electrode connecting end of the top electrode is provided with a suspension wing, the first acoustic impedance layer covers a part of the electrode connecting end of the bottom electrode, and the inner end of the suspension wing of the top electrode is positioned on the inner side of the boundary of the first acoustic impedance layer covering the electrode connecting end of the bottom electrode in the transverse direction; or
The electrode connecting end or the non-electrode connecting end of the bottom electrode comprises a bridge structure, the first acoustic impedance layer partially covers the electrode connecting end or the non-electrode connecting end of the bottom electrode, and the inner end of the bridge structure of the bottom electrode is arranged on the inner side of the boundary of the first acoustic impedance layer in the transverse direction; or
The non-electrode connecting end of one electrode in the top electrode or the bottom electrode is of a non-suspended wing structure, the electrode connecting end or the non-electrode connecting end of the other electrode in the top electrode or the bottom electrode comprises a bridge structure, and the edge of the non-electrode connecting end of the one electrode is arranged between the inner end and the outer end of the corresponding bridge structure of the other electrode in the transverse direction; or
The non-electrode connecting end of one of the top electrode or the bottom electrode is provided with a suspension wing, the electrode connecting end or the non-electrode connecting end of the other one of the top electrode or the bottom electrode is provided with a bridge structure, and the inner end of the suspension wing is positioned between the inner end and the outer end of the corresponding bridge structure in the transverse direction, or the inner end of the suspension wing is positioned on the inner side of the inner end of the corresponding bridge structure in the transverse direction.
20. The resonator of claim 1, wherein:
an electrode connection end of one of the top electrode and the bottom electrode is provided with a bridge structure, and a non-electrode connection end of the other of the top electrode and the bottom electrode and the bridge structure have an overlapping region in a thickness direction of the resonator.
21. The resonator of claim 1, wherein:
the acoustic mirror is an acoustic mirror cavity;
the boundary of the acoustic mirror cavity in the lateral direction of the resonator is defined by the first acoustic impedance layer.
22. The resonator of any one of claims 1-21, wherein:
the piezoelectric layer is a single crystal piezoelectric layer.
23. The resonator of any of claims 1-22, wherein:
the widths of the parts of the first acoustic impedance layer and the second acoustic impedance layer in contact with the piezoelectric layer are m lambda3A/4 and n lambda4A/4, where m and n are both odd numbers, λ3And λ4Respectively, the acoustic wave wavelengths that propagate in the lateral direction at the resonance frequency at the corresponding portions of the first acoustic impedance layer and the second acoustic impedance layer in contact with the piezoelectric layer.
24. The resonator of any of claims 1-22, wherein:
the material forming one of the first and second acoustic impedance layers is selected from the group consisting of aluminum nitride, silicon dioxide, silicon nitride, polysilicon, amorphous silicon, the material forming the other of the first and second acoustic impedance layers is selected from the group consisting of silicon dioxide, doped silicon dioxide, polysilicon, amorphous silicon, and the material forming the first acoustic impedance layer is different from the material forming the second acoustic impedance layer.
25. The resonator of any of claims 1-22, wherein:
the electrode connection end of the bottom electrode is covered with a part of the first acoustic impedance layer.
26. A bulk acoustic wave resonator assembly comprising:
at least two resonators as claimed in any of claims 1-25, said at least two resonators sharing a common substrate.
27. A filter comprising a bulk acoustic wave resonator according to any one of claims 1-25, or a bulk acoustic wave resonator assembly according to 26.
28. An electronic device comprising a filter according to 27, or a bulk acoustic wave resonator according to any of claims 1-25, or a bulk acoustic wave resonator assembly according to 26.
The electronic device includes, but is not limited to, intermediate products such as a radio frequency front end and a filtering and amplifying module, and terminal products such as a mobile phone, WIFI and an unmanned aerial vehicle.
Although embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.
Claims (28)
1. A bulk acoustic wave resonator comprising:
a substrate;
an acoustic mirror;
a bottom electrode;
a top electrode; and
a piezoelectric layer disposed between the bottom electrode and the top electrode,
wherein:
an acoustic impedance structure is arranged between the piezoelectric layer and the substrate;
the acoustic impedance structure includes a first acoustic impedance layer and a second acoustic impedance layer disposed adjacent to each other in a lateral direction, the first acoustic impedance layer being different in acoustic impedance from the second acoustic impedance layer, the acoustic mirror being located between the first acoustic impedance layers in the lateral direction of the resonator; and is
The bottom electrode and/or the top electrode are provided with a cantilever and/or a bridge structure.
2. The resonator of claim 1, wherein:
the non-electrode connecting end of the bottom electrode and/or the top electrode is/are provided with a suspension wing, and in the transverse direction of the resonator, a first distance exists between the outer edge of the suspension wing and the corresponding first acoustic impedance layer in the transverse direction; or the non-electrode connecting end of the bottom electrode and/or the top electrode is of a non-suspended wing structure, and a third distance exists between the outer edge of the non-electrode connecting end and the corresponding first acoustic impedance layer in the transverse direction of the resonator.
3. The resonator of claim 2, wherein:
the first distance is in the range of 0-50 μm; and/or
The third distance is in the range of 0-50 μm.
4. The resonator of claim 2, wherein:
the outer edge of the overhang wing of the top electrode is inside the boundary of the first acoustic impedance layer on the side of the electrode connection end of the bottom electrode in the lateral direction of the resonator; or
The outer edge of the overhang wing of the top electrode is outside the boundary of the first acoustic impedance layer on one side of the electrode connection end of the bottom electrode in the transverse direction of the resonator; or
The non-electrode connecting end of the top electrode is of a non-suspension wing structure, the non-electrode connecting portion of the bottom electrode comprises a suspension wing, and in the transverse direction of the resonator, the edge of the non-electrode connecting end of the top electrode is located on the outer side of the inner end of the suspension wing of the bottom electrode.
5. The resonator of claim 2, wherein:
the first distance is λ1Odd multiples of/4, λ1The first distance corresponds to the wavelength of an acoustic wave propagating in the lateral direction at the resonance frequency of the laminated structure in the thickness direction of the region.
6. The resonator of claim 2, wherein:
the width of the suspension wings in the lateral direction of the resonator is in the range of 0-50 μm.
7. The resonator of claim 2, wherein:
and the non-electrode connecting end of only the top electrode or only the bottom electrode in the bottom electrode and the top electrode is provided with a suspension wing.
8. The resonator of any of claims 1-7, wherein:
the electrode connecting end and/or the non-electrode connecting end of the bottom electrode and/or the top electrode are/is provided with a bridge structure; and is
In a lateral direction of the resonator, an outer edge of the bridge structure is present at a fifth distance to the corresponding first acoustic impedance layer.
9. The resonator of claim 8, wherein:
the fifth distance is in the range of 0-50 μm.
10. The resonator of claim 8, wherein:
the outer edge of the bridge structure is outside the boundary of the first acoustic impedance layer on the side of the electrode connection end of the bottom electrode in the lateral direction of the resonator.
11. The resonator of claim 8, wherein:
a fifth distance λ2Odd multiples of/4, λ2The fifth distance corresponds to the wavelength of an acoustic wave propagating in the lateral direction at the resonance frequency of the laminated structure in the thickness direction of the region.
12. The resonator of claim 8, wherein:
the width of the bridge structure is in the range of 0-50 μm.
13. The resonator of any of claims 8-12, wherein:
the electrode connecting end and/or the non-electrode connecting end of one of the top electrode and the bottom electrode is provided with a bridge structure, and the non-electrode connecting end of the other of the top electrode and the bottom electrode is provided with a suspension wing or a bridge structure.
14. The resonator of claim 13, wherein:
the top electrode and the bottom electrode are both provided with a suspension wing and a bridge structure.
15. The resonator of claim 13, wherein:
the inner edges of the overhangs of one of the top and bottom electrodes are aligned with the inner edges of the corresponding bridge structure or overhang structure of the other of the top and bottom electrodes in the thickness direction of the resonator.
16. The resonator of claim 13, wherein:
the inner edge of the cantilever of one of the top and bottom electrodes is offset in the lateral direction from the inner edge of the corresponding bridge structure or cantilever structure of the other of the top and bottom electrodes.
17. The resonator of claim 16, wherein:
the inner edge of the cantilever of one of the top and bottom electrodes is spaced from the inner edge of the corresponding bridge structure or cantilever structure of the other of the top and bottom electrodes by a first distance in the lateral direction.
18. The resonator of claim 17, wherein:
the first interval is in the range of 0-50 μm.
19. The resonator of claim 8, wherein:
the electrode connecting end of the top electrode is provided with a bridge structure, the first acoustic impedance layer covers a part of the non-electrode connecting end of the bottom electrode, in the transverse direction, the boundary of the first acoustic impedance layer is positioned on the inner side of the edge of the non-electrode connecting end of the bottom electrode, the inner side of the bridge structure of the top electrode is positioned on the inner side of the boundary of the first acoustic impedance layer, and the outer side of the bridge structure of the top electrode is positioned on the outer side of the edge of the non-electrode connecting end of the bottom electrode; or
The non-electrode connecting end of the top electrode is provided with a suspension wing, the first acoustic impedance layer covers a part of the electrode connecting end of the bottom electrode, and the inner end of the suspension wing of the top electrode is positioned on the inner side of the boundary of the first acoustic impedance layer covering the electrode connecting end of the bottom electrode in the transverse direction; or
The electrode connecting end or the non-electrode connecting end of the bottom electrode comprises a bridge structure, the first acoustic impedance layer partially covers the electrode connecting end or the non-electrode connecting end of the bottom electrode, and the inner end of the bridge structure of the bottom electrode is arranged on the inner side of the boundary of the first acoustic impedance layer in the transverse direction; or
The non-electrode connecting end of one electrode in the top electrode or the bottom electrode is of a non-suspended wing structure, the electrode connecting end or the non-electrode connecting end of the other electrode in the top electrode or the bottom electrode comprises a bridge structure, and the edge of the non-electrode connecting end of the one electrode is arranged between the inner end and the outer end of the corresponding bridge structure of the other electrode in the transverse direction; or
The non-electrode connecting end of one of the top electrode or the bottom electrode is provided with a suspension wing, the electrode connecting end or the non-electrode connecting end of the other one of the top electrode or the bottom electrode is provided with a bridge structure, and the inner end of the suspension wing is positioned between the inner end and the outer end of the corresponding bridge structure in the transverse direction, or the inner end of the suspension wing is positioned on the inner side of the inner end of the corresponding bridge structure in the transverse direction.
20. The resonator of claim 1, wherein:
an electrode connection end of one of the top electrode and the bottom electrode is provided with a bridge structure, and a non-electrode connection end of the other of the top electrode and the bottom electrode and the bridge structure have an overlapping region in a thickness direction of the resonator.
21. The resonator of claim 1, wherein:
the acoustic mirror is an acoustic mirror cavity;
the boundary of the acoustic mirror cavity in the lateral direction of the resonator is defined by the first acoustic impedance layer.
22. The resonator of any one of claims 1-21, wherein:
the piezoelectric layer is a single crystal piezoelectric layer.
23. The resonator of any of claims 1-22, wherein:
the widths of the parts of the first acoustic impedance layer and the second acoustic impedance layer in contact with the piezoelectric layer are m lambda3A/4 and n lambda4A/4, where m and n are both odd numbers, λ3And λ4Respectively, the acoustic wave wavelengths that propagate in the lateral direction at the resonance frequency at the corresponding portions of the first acoustic impedance layer and the second acoustic impedance layer in contact with the piezoelectric layer.
24. The resonator of any of claims 1-22, wherein:
the material forming one of the first and second acoustic impedance layers is selected from the group consisting of aluminum nitride, silicon dioxide, silicon nitride, polysilicon, amorphous silicon, the material forming the other of the first and second acoustic impedance layers is selected from the group consisting of silicon dioxide, doped silicon dioxide, polysilicon, amorphous silicon, and the material forming the first acoustic impedance layer is different from the material forming the second acoustic impedance layer.
25. The resonator of any of claims 1-22, wherein:
the electrode connection end of the bottom electrode is covered with a part of the first acoustic impedance layer.
26. A bulk acoustic wave resonator assembly comprising:
at least two resonators as claimed in any of claims 1-25, the at least two resonators sharing a common substrate.
27. A filter comprising the bulk acoustic wave resonator of any one of claims 1-25, or the bulk acoustic wave resonator assembly of claim 26.
28. An electronic device comprising the filter of claim 27, or the bulk acoustic wave resonator of any one of claims 1-25, or the bulk acoustic wave resonator assembly of claim 26.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010779406.XA CN114070234A (en) | 2020-08-05 | 2020-08-05 | Bulk acoustic wave resonator, bulk acoustic wave resonator component, filter, and electronic device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010779406.XA CN114070234A (en) | 2020-08-05 | 2020-08-05 | Bulk acoustic wave resonator, bulk acoustic wave resonator component, filter, and electronic device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114070234A true CN114070234A (en) | 2022-02-18 |
Family
ID=80232131
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010779406.XA Pending CN114070234A (en) | 2020-08-05 | 2020-08-05 | Bulk acoustic wave resonator, bulk acoustic wave resonator component, filter, and electronic device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114070234A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117595819A (en) * | 2023-02-23 | 2024-02-23 | 北京芯溪半导体科技有限公司 | Resonator, filter, duplexer, multiplexer and communication equipment |
-
2020
- 2020-08-05 CN CN202010779406.XA patent/CN114070234A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117595819A (en) * | 2023-02-23 | 2024-02-23 | 北京芯溪半导体科技有限公司 | Resonator, filter, duplexer, multiplexer and communication equipment |
| CN117595819B (en) * | 2023-02-23 | 2024-06-04 | 北京芯溪半导体科技有限公司 | Resonator, filter, duplexer, multiplexer and communication equipment |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111865248B (en) | Resonator assembly, semiconductor device, electronic apparatus, and method of manufacturing resonator assembly | |
| US10284173B2 (en) | Acoustic resonator device with at least one air-ring and frame | |
| CN113497596B (en) | Bulk acoustic wave resonator, bulk acoustic wave resonator assembly, filter, and electronic device | |
| US9490770B2 (en) | Acoustic resonator comprising temperature compensating layer and perimeter distributed bragg reflector | |
| EP4027517A1 (en) | Bulk acoustic wave resonator with piezoelectric layer having insert structure, and filter and electronic device | |
| CN111934643B (en) | Bulk acoustic wave resonator with mass loads arranged on two sides of piezoelectric layer, filter and electronic equipment | |
| EP1217734A2 (en) | Bulk acoustic resonator perimeter reflection system | |
| US12021505B2 (en) | High Q BAW resonator with spurious mode suppression | |
| CN110611493A (en) | Acoustic wave resonator, acoustic wave resonator filter including the same, and method of manufacturing the same | |
| CN110868182B (en) | Resonator and filter | |
| CN111313857A (en) | Bulk acoustic wave resonator, filter, and electronic device provided with insertion structure and temperature compensation layer | |
| CN112383286B (en) | Bulk acoustic wave resonator assembly, method of manufacturing the same, filter, and electronic apparatus | |
| US20220407494A1 (en) | Acoustic wave device and method of manufacturing the same | |
| CN114070233A (en) | Bulk acoustic wave resonator, filter and electronic device with reduced parasitic mode | |
| CN114696774A (en) | Single crystal acoustic wave resonator, filter, and electronic device | |
| CN114389559A (en) | Bulk acoustic wave resonator, bulk acoustic wave resonator component, filter, and electronic device | |
| CN115622526A (en) | Bulk acoustic wave resonator and preparation method thereof | |
| CN114070234A (en) | Bulk acoustic wave resonator, bulk acoustic wave resonator component, filter, and electronic device | |
| CN116896346A (en) | Bulk acoustic wave resonator, forming method, filter, communication equipment and terminal | |
| KR102172638B1 (en) | Acoustic resonator and method of manufacturing thereof | |
| CN117013979B (en) | Bulk acoustic wave resonator, preparation method thereof, filter and electronic equipment | |
| KR20220050596A (en) | Bulk-acoustic wave resonator | |
| CN117013978B (en) | Bulk acoustic wave resonator, preparation method thereof, filter and electronic equipment | |
| CN117176101A (en) | Bulk acoustic wave resonator, preparation method thereof, filter and electronic equipment | |
| CN114070252A (en) | Bulk acoustic wave resonator, bulk acoustic wave resonator component, filter, and electronic device |
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 |