CN117254789A - Surface acoustic wave resonator for inhibiting in-band harmonic wave - Google Patents
Surface acoustic wave resonator for inhibiting in-band harmonic wave Download PDFInfo
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- CN117254789A CN117254789A CN202311522935.1A CN202311522935A CN117254789A CN 117254789 A CN117254789 A CN 117254789A CN 202311522935 A CN202311522935 A CN 202311522935A CN 117254789 A CN117254789 A CN 117254789A
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- 238000010897 surface acoustic wave method Methods 0.000 title claims abstract description 58
- 230000002401 inhibitory effect Effects 0.000 title description 4
- 229910052751 metal Inorganic materials 0.000 claims abstract description 107
- 239000002184 metal Substances 0.000 claims abstract description 107
- 239000000758 substrate Substances 0.000 claims abstract description 23
- 230000026683 transduction Effects 0.000 claims abstract description 16
- 238000010361 transduction Methods 0.000 claims abstract description 16
- 238000002161 passivation Methods 0.000 claims description 31
- 239000007788 liquid Substances 0.000 claims 1
- 238000003780 insertion Methods 0.000 abstract description 16
- 230000037431 insertion Effects 0.000 abstract description 16
- 238000000034 method Methods 0.000 description 7
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 3
- 229910052581 Si3N4 Inorganic materials 0.000 description 3
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-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
- 229910052804 chromium Inorganic materials 0.000 description 3
- 239000011651 chromium Substances 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 229910052750 molybdenum Inorganic materials 0.000 description 3
- 239000011733 molybdenum Substances 0.000 description 3
- 229910052697 platinum Inorganic materials 0.000 description 3
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 3
- 229910052709 silver Inorganic materials 0.000 description 3
- 239000004332 silver Substances 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- 239000010936 titanium 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
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 235000012239 silicon dioxide Nutrition 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 description 1
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
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
- H03H9/25—Constructional features of resonators using surface acoustic waves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
- B81B7/02—Microstructural systems; Auxiliary parts of microstructural devices or systems containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS]
-
- 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
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02818—Means for compensation or elimination of undesirable effects
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02818—Means for compensation or elimination of undesirable effects
- H03H9/02834—Means for compensation or elimination of undesirable effects of temperature influence
-
- 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
- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/145—Driving means, e.g. electrodes, coils for networks using surface acoustic waves
- H03H9/14544—Transducers of particular shape or position
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- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Abstract
The application relates to the technical field of resonators, and discloses a surface acoustic wave resonator for suppressing in-band harmonics, which comprises: a piezoelectric substrate for acoustic-electric transduction; the outer surface of the piezoelectric substrate is provided with an interdigital electrode structure; an interdigital electrode structure for exciting acoustic-electric transduction by applying a voltage; a first temperature compensation layer wrapping the interdigital electrode structure; a plurality of metal strips arranged on the first temperature compensation layer; each metal strip is arranged at the end area of the electrode finger of the interdigital electrode structure, and at least part of the metal strips have inconsistent widths. In this way, by arranging the metal strips with inconsistent widths in the electrode finger tail end regions of the interdigital electrode structure, harmonic waves can be well restrained, and the insertion loss function of the surface acoustic wave resonator is improved. The application also discloses MEMS equipment.
Description
Technical Field
The present application relates to the technical field of resonators, for example, to a surface acoustic wave resonator and MEMS device for suppressing in-band harmonics.
Background
With the continuous development of science and technology, the types of resonators are also becoming more and more widespread. The frequency range of the surface acoustic wave resonator is far higher than that of other types of resonators, and the temperature stability of the surface acoustic wave resonator is better than that of the other types of resonators, so that the surface acoustic wave resonator has wide application prospect. However, in the process of using the surface acoustic wave resonator, the insertion loss in the passband of the surface acoustic wave resonator may fluctuate greatly due to the influence of various harmonics, and even may deteriorate seriously. Therefore, how to improve the insertion loss function of the surface acoustic wave resonator needs to be solved.
Disclosure of Invention
The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed embodiments. This summary is not an extensive overview, and is intended to neither identify key/critical elements nor delineate the scope of such embodiments, but is intended as a prelude to the more detailed description that follows.
The embodiment of the invention provides a surface acoustic wave resonator and MEMS (micro electro mechanical system) equipment for inhibiting in-band harmonic waves so as to improve the insertion loss function of the surface acoustic wave resonator.
In some embodiments, a surface acoustic wave resonator includes: a piezoelectric substrate for acoustic-electric transduction; the outer surface of the piezoelectric substrate is provided with an interdigital electrode structure; an interdigital electrode structure for exciting acoustic-electric transduction by applying a voltage; a first temperature compensation layer wrapping the interdigital electrode structure; a plurality of metal strips arranged on the first temperature compensation layer; each metal strip is arranged at the end area of the electrode finger of the interdigital electrode structure, and at least part of the metal strips have inconsistent widths.
In some embodiments, the surface acoustic wave resonator further comprises: and a first passivation layer disposed on the metal strip and the first temperature compensation layer uncovered by the metal strip.
In some embodiments, the surface acoustic wave resonator further comprises: the second temperature compensation layer is arranged on one side of the first passivation layer far away from the metal strip.
In some embodiments, the first temperature compensation layer is provided with a first via; the second temperature compensation layer is provided with a second through hole; the first passivation layer is provided with a third through hole; the first through hole, the second through hole and the third through hole are communicated, and the bus bar of the interdigital electrode structure is exposed; the surface acoustic wave resonator further includes: and the metal layer is connected with the bus bar of the interdigital electrode structure through the first through hole, the second through hole and the third through hole.
In some embodiments, the surface acoustic wave resonator further comprises: and the second passivation layer is arranged on the second temperature compensation layer and the metal layer.
In some embodiments, the width of the metal strip is obtained by: calculating p multiplied by L to obtain the width of the metal strip; p is a preset parameter; l is the acoustic wavelength corresponding to the harmonic frequency.
In some embodiments, the length of the metal strip is obtained by: calculating n multiplied by L to obtain the length of the metal strip; n is a positive integer; l is the acoustic wavelength corresponding to the harmonic frequency.
In some embodiments, the position and number of metal strips may be freely adjusted.
In some embodiments, the MEMS device employs a surface acoustic wave resonator as described above that suppresses in-band harmonics.
In some embodiments, the MEMS device includes a level sensor, an oscillator, a microphone, a radio frequency switch, or a filter.
The embodiment of the invention provides a surface acoustic wave resonator and MEMS (micro electro mechanical systems) equipment for inhibiting in-band harmonic waves, which can realize the following technical effects: by providing a piezoelectric substrate for acoustic-electric transduction, an interdigital electrode structure for exciting acoustic-electric transduction by applying a voltage is provided on the outer surface of the piezoelectric substrate. And arranging a first temperature compensation layer to wrap the interdigital electrode structure. And a plurality of metal strips are arranged on the first temperature compensation layer, each metal strip is positioned at the tail end area of the electrode finger of the interdigital electrode structure, and at least part of the metal strips have inconsistent widths. In this way, by arranging the metal strips with inconsistent widths in the electrode finger tail end regions of the interdigital electrode structure, harmonic waves can be well restrained, and the insertion loss function of the surface acoustic wave resonator is improved.
The foregoing general description and the following description are exemplary and explanatory only and are not restrictive of the application.
Drawings
One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements, and in which like reference numerals refer to similar elements, and in which:
fig. 1 is a cross-sectional view of a conventional surface acoustic wave filter according to an embodiment of the present invention along the section line α - α' shown in fig. 2;
FIG. 2 is a schematic diagram showing the interdigital electrode structure and the distribution of a plurality of metal strips of a conventional SAW resonator in accordance with an embodiment of the present invention;
FIG. 3 is a schematic diagram showing the interdigital electrode structure and the distribution of a plurality of metal strips of a SAW resonator provided by an embodiment of the present invention;
fig. 4 is a cross-sectional view of a surface acoustic wave filter according to an embodiment of the present invention along the section line α - α' shown in fig. 3;
fig. 5 is a schematic diagram of a frequency response curve of a surface acoustic wave resonator according to an embodiment of the present invention.
Reference numerals:
1: a piezoelectric substrate; 2: interdigital electrodes; 3: a third passivation layer; 4: a first temperature compensation layer; 5: a first passivation layer; 6: a second temperature compensation layer; 7: a second passivation layer; 8: a metal layer; 9: a metal strip; 10: a first bus bar; 11: a second bus bar; 12: a third bus bar; 13: a first electrode finger; 14: a second electrode finger; 15: a third electrode finger; 16: and a fourth electrode finger.
Detailed Description
For a more complete understanding of the nature and the technical content of the embodiments of the present invention, reference should be made to the following detailed description of embodiments of the invention, taken in conjunction with the accompanying drawings, which are meant to be illustrative only and not limiting of the embodiments of the invention. In the following description of the technology, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, one or more embodiments may still be practiced without these details. In other instances, well-known structures and devices may be shown simplified in order to simplify the drawing.
The terms first, second and the like in the description and in the claims of embodiments of the invention and in the above-described figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate in order to describe embodiments of the invention herein. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion.
In the embodiments of the present invention, the terms "upper", "lower", "inner", "middle", "outer", "front", "rear", and the like indicate the azimuth or the positional relationship based on the azimuth or the positional relationship shown in the drawings. These terms are only used to facilitate a better description of embodiments of the invention and their examples and are not intended to limit the scope of the indicated devices, elements or components to the particular orientation or to be constructed and operated in a particular orientation. Also, some of the terms described above may be used to indicate other meanings in addition to orientation or positional relationships, for example, the term "upper" may also be used to indicate some sort of attachment or connection in some cases. The specific meaning of these terms in embodiments of the present invention will be understood by those of ordinary skill in the art in view of the specific circumstances.
In addition, the terms "disposed," "connected," "secured" and "affixed" are to be construed broadly. For example, "connected" may be in a fixed connection, a removable connection, or a unitary construction; may be a mechanical connection, or an electrical connection; may be directly connected, or indirectly connected through intervening media, or may be in internal communication between two devices, elements, or components. The specific meaning of the above terms in the embodiments of the present invention will be understood by those of ordinary skill in the art according to the specific circumstances.
The term "plurality" means two or more, unless otherwise indicated.
In the embodiment of the invention, the character "/" indicates that the front object and the rear object are in an OR relationship. For example, A/B represents: a or B.
The term "and/or" is an associative relationship that describes an object, meaning that there may be three relationships. For example, a and/or B, represent: a or B, or, A and B.
It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.
In some embodiments, as shown in fig. 1 and 2, the following structure is generally adopted in the related art to enhance the insertion loss function of the acoustic surface resonator. The outer surface of the piezoelectric substrate 1 is provided with an interdigital electrode structure. The interdigital electrode structure includes an interdigital electrode 2 and a third passivation layer 3 disposed on the interdigital electrode. The first temperature compensation layer 4 is arranged on the interdigital electrode structure, the interdigital electrode structure is partially wrapped by the first temperature compensation layer 4, the first temperature compensation layer 4 is provided with a first through hole, and the first through hole exposes the bus bar of the interdigital electrode structure. The first temperature compensation layer 4 is provided with metal strips 9, each metal strip 9 is arranged at the end regions of the electrode fingers of the interdigital electrode structure, and the length of each metal strip 9 is equal to the width of the piezoelectric substrate 1. A first passivation layer 5 is provided on the metal strip 9 and the first temperature compensation layer 4 not covered by the metal strip 9. The first passivation layer 5 is provided with a third through hole, which communicates with the first through hole, exposing the bus bar of the interdigital electrode structure. A second temperature compensation layer 6 is provided on the side of the first passivation layer 5 remote from the metal strip 9. The second temperature compensation layer 6 is provided with a second through hole, and the first through hole, the second through hole and the third through hole are communicated to expose the bus bar of the interdigital electrode structure. The metal layer 8 is connected to the bus bar of the interdigital electrode structure through the first through hole, the second through hole and the third through hole. A second passivation layer 7 is provided on the second temperature compensation layer 6 and the metal layer 8.
The interdigital electrode structure comprises a first bus bar 10, a second bus bar 11, a third bus bar 12, a first electrode finger 13, a second electrode finger 14, a third electrode finger 15 and a fourth electrode finger 16. The first bus bar 10, the second bus bar 11, and the third bus bar 12 are parallel to each other. The first electrode fingers 13 and the second electrode fingers 14 are alternately arranged to be interdigital. The third electrode fingers 15 and the fourth electrode fingers 16 are alternately arranged in an interdigital shape. The first electrode finger 13 is an electrode finger vertically connected to the first bus bar 10. The fourth electrode finger 16 is an electrode finger vertically connected to the third bus bar 12. The second electrode finger 14 is an electrode finger vertically disposed on one side of the second bus bar 11 near the first bus bar 10. The third electrode finger 15 is an electrode finger vertically disposed on one side of the second bus bar 11 near the third bus bar 12. At this time, the electrode finger tip regions, i.e., the first electrode finger tip region, the second electrode finger tip region, the third electrode finger tip region, and the fourth electrode finger tip region. And arranging a metal strip with equal width in the end area of the first electrode finger, the end area of the second electrode finger, the end area of the third electrode finger and the end area of the fourth electrode finger respectively. However, the insertion loss function of the saw resonator is still poor only by providing one metal strip with equal width in the first electrode finger end region, the second electrode finger end region, the third electrode finger end region and the fourth electrode finger end region.
The embodiment of the invention provides a surface acoustic wave resonator, which comprises: the piezoelectric device comprises a piezoelectric substrate, an interdigital electrode structure, a first temperature compensation layer and a plurality of metal strips. A piezoelectric substrate for acoustic-electric transduction; the outer surface of the piezoelectric substrate is provided with an interdigital electrode structure; an interdigital electrode structure for exciting acoustic-electric transduction by applying a voltage; a first temperature compensation layer wrapping the interdigital electrode structure; a plurality of metal strips arranged on the first temperature compensation layer; each metal strip is arranged at the end area of the electrode finger of the interdigital electrode structure, and at least part of the metal strips have inconsistent widths.
By adopting the surface acoustic wave resonator provided by the embodiment of the disclosure, the piezoelectric substrate for acoustic-electric transduction is arranged, and the interdigital electrode structure for exciting the acoustic-electric transduction by applying voltage is arranged on the outer surface of the piezoelectric substrate. And arranging a first temperature compensation layer to wrap the interdigital electrode structure. And a plurality of metal strips are arranged on the first temperature compensation layer, each metal strip is positioned at the tail end area of the electrode finger of the interdigital electrode structure, and at least part of the metal strips have inconsistent widths. In this way, by arranging the metal strips with inconsistent widths in the electrode finger tail end regions of the interdigital electrode structure, harmonic waves can be well restrained, and the insertion loss function of the surface acoustic wave resonator is improved.
In some embodiments, the interdigitated electrode structure includes a plurality of bus bars and electrode fingers that connect the bus bars vertically. The electrode finger end region is the region where the end of the electrode finger is located and the region of the electrode finger that is flush with the region where the end of the electrode is located. And taking the region from the tail end edge of the electrode finger to the preset edge of the electrode finger as the region where the tail end of the electrode finger is positioned. The preset edge of the electrode finger is a position on the electrode finger, wherein the vertical distance of the electrode finger and the edge of the tail end of the electrode finger keep a preset length.
Optionally, the interdigital electrode structure comprises: interdigital electrodes.
Optionally, the interdigital electrode structure comprises: an interdigital electrode and a third passivation layer disposed on the interdigital electrode.
Optionally, the interdigital electrode comprises: the first bus bar, the second bus bar, the third bus bar, the first electrode finger, the second electrode finger, the third electrode finger and the fourth electrode finger. The first bus bar, the second bus bar, and the third bus bar are parallel to each other. The first electrode fingers and the second electrode fingers are alternately arranged to be interdigital. The third electrode fingers and the fourth electrode fingers are alternately arranged to be interdigital. The first electrode fingers are electrode fingers vertically connected with the first bus bar. The fourth electrode finger is an electrode finger vertically connected with the third bus bar. The second electrode finger is an electrode finger vertically arranged on one side of the second bus bar, which is close to the first bus bar. The third electrode finger is an electrode finger vertically arranged on one side, close to the third bus bar, of the second bus bar.
In some embodiments, as shown in connection with fig. 3, fig. 3 is a schematic diagram of the interdigital electrode structure and the distribution of a plurality of metal strips of a surface acoustic wave resonator. The interdigital electrode structure includes a first bus bar 10, a second bus bar 11, a third bus bar 12, a first electrode finger 13, a second electrode finger 14, a third electrode finger 15, and a fourth electrode finger 16. The first bus bar 10, the second bus bar 11, and the third bus bar 12 are parallel to each other. The first electrode fingers 13 and the second electrode fingers 14 are alternately arranged to be interdigital. The third electrode fingers 15 and the fourth electrode fingers 16 are alternately arranged in an interdigital shape. The first electrode finger 13 is an electrode finger vertically connected to the first bus bar 10. The fourth electrode finger 16 is an electrode finger vertically connected to the third bus bar 12. The second electrode finger 14 is an electrode finger vertically disposed on one side of the second bus bar 11 near the first bus bar 10. The third electrode finger 15 is an electrode finger vertically disposed on one side of the second bus bar 11 near the third bus bar 12. At this time, the electrode finger tip regions, i.e., the first electrode finger tip region, the second electrode finger tip region, the first electrode finger tip region, and the second electrode finger tip region. The region of the first electrode finger 13 that is flush with the end of the second electrode finger 14 and the region of the end of the second electrode finger 14 are referred to as a first electrode finger end region. The region of the second electrode finger 14 that is flush with the end of the first electrode finger 13 and the region of the end of the first electrode finger 13 are referred to as second electrode finger end regions. The region of the third electrode finger 15 that is flush with the end of the fourth electrode finger 16, and the region of the end of the fourth electrode finger 16, is referred to as a third electrode finger end region. The region of the fourth electrode finger 16 that is flush with the end of the third electrode finger 15 is referred to as a fourth electrode finger end region. Two metal strips 9 are arranged in the end region of the first electrode finger, and the widths of the two metal strips 9 are not equal. Two metal strips 9 are arranged in the end region of the second electrode finger, and the widths of the two metal strips 9 are unequal. Two metal strips 9 are arranged in the third electrode finger end regions, and the widths of the two metal strips 9 are not equal. Two metal strips 9 are arranged in the end region of the fourth electrode finger, and the widths of the two metal strips 9 are unequal.
In some embodiments, the electrode finger tip regions include a first electrode finger tip region, a second electrode finger tip region, a third electrode finger tip region, and a fourth electrode finger tip region. The first electrode finger tip region is provided with at least 2 metal strips. The second electrode finger tip region is provided with at least 2 metal strips. The third electrode finger tip region is provided with at least 2 metal strips. The fourth electrode finger tip region is provided with at least 2 metal strips.
Optionally, the interdigital electrode comprises: a fourth bus bar, a fifth bus bar, and a plurality of electrode fingers. The fourth bus bar and the fifth bus bar are parallel to each other. The electrode fingers vertically connected on the fourth bus bar are fifth electrode fingers; the electrode finger vertically connected on the fifth bus bar is a sixth electrode finger. The fifth electrode fingers of the fourth bus bar and the sixth electrode fingers of the fifth bus bar are alternately arranged in an interdigital shape.
Optionally, the surface acoustic wave resonator further includes: and a first passivation layer disposed on the metal strip and the first temperature compensation layer uncovered by the metal strip. In this way, the first passivation layer is arranged, so that the metal strip can be better protected.
Optionally, the surface acoustic wave resonator further includes: the second temperature compensation layer is arranged on one side of the first passivation layer far away from the metal strip.
Optionally, the first temperature compensation layer is provided with a first through hole; the second temperature compensation layer is provided with a second through hole; the first passivation layer is provided with a third through hole; the first through hole, the second through hole and the third through hole are communicated, and the bus bar of the interdigital electrode structure is exposed; the surface acoustic wave resonator further includes: and the metal layer is connected with the bus bar of the interdigital electrode structure through the first through hole, the second through hole and the third through hole.
Optionally, the surface acoustic wave resonator further includes: and the second passivation layer is arranged on the second temperature compensation layer and the metal layer.
In some embodiments, as shown in connection with fig. 4, fig. 4 is a cross-sectional view of the saw filter along the α - α' section line shown in fig. 3. As shown in fig. 4, the outer surface of the piezoelectric substrate 1 is provided with an interdigital electrode structure. The interdigital electrode structure comprises an interdigital electrode 2 and a third passivation layer 3 arranged on the interdigital electrode 2, wherein the third passivation layer 3 is provided with a fourth through hole, and the fourth through hole exposes a bus bar of the interdigital electrode. The first temperature compensation layer 4 is arranged on the interdigital electrode structure, the interdigital electrode structure is wrapped by the first temperature compensation layer 4, the first temperature compensation layer 4 is provided with a first through hole, and the first through hole is communicated with a fourth through hole to expose a bus bar of the interdigital electrode structure. A plurality of metal strips 9 are arranged on the first temperature compensation layer 4, each metal strip 9 is arranged at the end area of the electrode finger of the interdigital electrode structure, and at least part of the metal strips 9 are inconsistent in length. A first passivation layer 5 is provided on the metal strip 9 and the first temperature compensation layer 4 not covered by the metal strip 9. The first passivation layer 5 is provided with a third through hole, which communicates with the first through hole, exposing the bus bar of the interdigital electrode structure. A second temperature compensation layer 6 is provided on the side of the first passivation layer 5 remote from the metal strip 9. The second temperature compensation layer 6 is provided with a second through hole, and the first through hole, the second through hole and the third through hole are communicated to expose the bus bar of the interdigital electrode structure. The metal layer 8 is connected to the bus bar of the interdigital electrode structure through the first through hole, the second through hole and the third through hole. A second passivation layer 7 is provided on the second temperature compensation layer 6 and the metal layer 8.
Alternatively, the width of the metal strip is obtained by: obtaining the width of the metal strip by calculating p×l; p is a preset parameter; l is the acoustic wavelength corresponding to the harmonic frequency. Wherein, the value range of p is as follows: 0.4 to 0.6.
In some embodiments, the widths of the metal strips disposed at the electrode finger tip regions of the saw resonator belong to a set of widths. In the case where the surface acoustic wave resonator has a plurality of harmonic frequencies, a plurality of metal bar widths are obtained by bringing the acoustic wave lengths respectively corresponding to the harmonic frequencies into the formula p×l. The width set is a set of a plurality of metal strip widths.
Alternatively, the length of the metal strip is obtained by: calculating n multiplied by L to obtain the length of the metal strip; n is a positive integer; l is the acoustic wavelength corresponding to the harmonic frequency.
In some embodiments, the lengths of the metal strips disposed at the electrode finger tip regions of the saw resonator belong to a set of lengths. In the case where the surface acoustic wave resonator has a plurality of harmonic frequencies, a plurality of metal bar lengths are obtained by bringing the acoustic wave lengths respectively corresponding to the harmonic frequencies into the formula n×l. The length set is a set of a plurality of metal strip lengths.
Optionally, the position and number of the metal strips can be freely adjusted, which is determined by the intensity of the harmonic and the effect on the insertion loss of the passband.
Alternatively, the piezoelectric substrate is made of lithium niobate crystal, lithium tantalate crystal, aluminum nitride, zinc oxide, or piezoelectric ceramic.
Optionally, the metal strip is composed of one or more metals of titanium, chromium, silver, copper, molybdenum, platinum, tungsten, and aluminum.
Optionally, the metal layer is composed of one or more metals of titanium, chromium, silver, copper, molybdenum, platinum, tungsten, and aluminum.
Optionally, the interdigitated electrodes are composed of one or more metals of titanium, chromium, silver, copper, molybdenum, platinum, tungsten, and aluminum.
Optionally, the first temperature compensation layer is made of silicon dioxide.
Optionally, the second temperature compensation layer is made of silicon dioxide.
Optionally, the first passivation layer is made of silicon nitride.
Optionally, the second passivation layer is made of silicon nitride.
Optionally, the third passivation layer is made of silicon nitride.
In some embodiments, as shown in connection with fig. 5, fig. 5 is a schematic diagram of a frequency response curve of a surface acoustic wave resonator. As shown in fig. 5, curve a is a frequency response curve of the surface acoustic wave resonator of the present application, and the S parameter is S (6, 4). Curve B is the frequency response curve of a non-surface acoustic wave resonator of the present application, and its S parameter is S (3, 1). At a Frequency (Frequency) of 880MHz, the Insertion Loss (Insertion Loss) for curve A is equal to-1.2332 dB and the Insertion Loss for curve B is equal to-1.2641 dB. At a frequency of 915MHz, the insertion loss for curve A is equal to-1.5572 dB and the insertion loss for curve B is equal to-1.1575 dB. As can be seen from fig. 5, the frequency response curve of the surface acoustic wave resonator of the present application is flatter than that of the surface acoustic wave resonator of the non-present application. Therefore, the insertion loss function of the surface acoustic wave resonator is better.
The embodiment of the invention provides MEMS equipment, which adopts the surface acoustic wave resonator for suppressing in-band harmonic waves. A surface acoustic wave resonator comprising: the piezoelectric device comprises a piezoelectric substrate, an interdigital electrode structure, a first temperature compensation layer and a plurality of metal strips. A piezoelectric substrate for acoustic-electric transduction; the outer surface of the piezoelectric substrate is provided with an interdigital electrode structure; an interdigital electrode structure for exciting acoustic-electric transduction by applying a voltage; a first temperature compensation layer wrapping the interdigital electrode structure; a plurality of metal strips arranged on the first temperature compensation layer; each metal strip is arranged at the end area of the electrode finger of the interdigital electrode structure, and at least part of the metal strips have inconsistent widths.
By adopting the MEMS device provided by the embodiment of the disclosure, the surface acoustic wave resonator is included by the MEMS device. The surface acoustic wave resonator is provided with a piezoelectric substrate for acoustic-electric transduction, and an interdigital electrode structure for exciting the acoustic-electric transduction by applying voltage is arranged on the outer surface of the piezoelectric substrate; arranging a first temperature compensation layer to wrap the interdigital electrode structure; and a plurality of metal strips are arranged on the first temperature compensation layer, each metal strip is positioned at the tail end area of the electrode finger of the interdigital electrode structure, and at least part of the metal strips have inconsistent widths. In this way, by arranging the metal strips with inconsistent widths in the electrode finger tail end regions of the interdigital electrode structure, harmonic waves can be well restrained, and the insertion loss function of the surface acoustic wave resonator is improved. Thereby improving the acoustic performance of the MEMS device.
Alternatively, MEMS (Micro-Electro-mechanical system) devices such as: level sensors, oscillators, microphones, radio frequency switches or filters, etc.
The above description and the drawings illustrate embodiments of the invention sufficiently to enable those skilled in the art to practice them. Other embodiments may involve structural, logical, electrical, process, and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the sequence of operations may vary. Portions and features of some embodiments may be included in, or substituted for, those of others. Moreover, the terminology used in the present application is for the purpose of describing embodiments only and is not intended to limit the claims. As used in the description of the embodiments and the claims, the singular forms "a," "an," and "the" (the) are intended to include the plural forms as well, unless the context clearly indicates otherwise. Similarly, the term "and/or" as used in this application is meant to encompass any and all possible combinations of one or more of the associated listed. Furthermore, when used in this application, the terms "comprises," "comprising," and/or "includes," and variations thereof, mean that the stated features, integers, steps, operations, elements, and/or components are present, but that the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof is not precluded. Without further limitation, an element defined by the phrase "comprising one …" does not exclude the presence of other like elements in a process, method or apparatus comprising such elements. In this context, each embodiment may be described with emphasis on the differences from the other embodiments, and the same similar parts between the various embodiments may be referred to each other. For the methods, products, etc. disclosed in the embodiments, if they correspond to the method sections disclosed in the embodiments, the description of the method sections may be referred to for relevance.
Claims (10)
1. A surface acoustic wave resonator that suppresses in-band harmonics, comprising:
a piezoelectric substrate for acoustic-electric transduction; the outer surface of the piezoelectric substrate is provided with an interdigital electrode structure;
an interdigital electrode structure for exciting acoustic-electric transduction by applying a voltage;
a first temperature compensation layer wrapping the interdigital electrode structure;
a plurality of metal strips arranged on the first temperature compensation layer; each metal strip is arranged at the end area of the electrode finger of the interdigital electrode structure, and at least part of the metal strips have inconsistent widths.
2. The surface acoustic wave resonator according to claim 1, characterized in that the surface acoustic wave resonator further comprises:
and a first passivation layer disposed on the metal strip and the first temperature compensation layer uncovered by the metal strip.
3. The surface acoustic wave resonator according to claim 2, characterized in that the surface acoustic wave resonator further comprises:
the second temperature compensation layer is arranged on one side of the first passivation layer far away from the metal strip.
4. A surface acoustic wave resonator according to claim 3, characterized in that the first temperature compensation layer is provided with a first through hole; the second temperature compensation layer is provided with a second through hole; the first passivation layer is provided with a third through hole; the first through hole, the second through hole and the third through hole are communicated, and the bus bar of the interdigital electrode structure is exposed; the surface acoustic wave resonator further includes:
and the metal layer is connected with the bus bar of the interdigital electrode structure through the first through hole, the second through hole and the third through hole.
5. The surface acoustic wave resonator according to claim 4, characterized in that the surface acoustic wave resonator further comprises:
and the second passivation layer is arranged on the second temperature compensation layer and the metal layer.
6. The surface acoustic wave resonator according to any of claims 1 to 5, characterized in that the width of the metal strip is obtained by: calculating p multiplied by L to obtain the width of the metal strip; p is a preset parameter; l is the acoustic wavelength corresponding to the harmonic frequency.
7. The surface acoustic wave resonator according to any of claims 1 to 5, characterized in that the length of the metal strip is obtained by: calculating n multiplied by L to obtain the length of the metal strip; n is a positive integer; l is the acoustic wavelength corresponding to the harmonic frequency.
8. The surface acoustic wave resonator according to any of claims 1 to 5, characterized in that the position and number of the metal strips are freely adjustable.
9. A MEMS device employing the surface acoustic wave resonator suppressing in-band harmonics according to any one of claims 1 to 8.
10. The MEMS device, as recited in claim 9, wherein the MEMS device comprises a liquid level sensor, an oscillator, a microphone, a radio frequency switch, or a filter.
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