CN113992178A - Reflection structure of plate wave resonator, and MEMS device - Google Patents

Reflection structure of plate wave resonator, and MEMS device Download PDF

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Publication number
CN113992178A
CN113992178A CN202111234538.5A CN202111234538A CN113992178A CN 113992178 A CN113992178 A CN 113992178A CN 202111234538 A CN202111234538 A CN 202111234538A CN 113992178 A CN113992178 A CN 113992178A
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electrode
reflection
interdigital transducer
wave resonator
plate wave
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不公告发明人
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Fudan University
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Fudan University
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/02535—Details of surface acoustic wave devices
    • H03H9/02637—Details concerning reflective or coupling arrays
    • 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
    • H03H9/02842—Means for compensation or elimination of undesirable effects of reflections
    • 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

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  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)

Abstract

The application relates to the technical field of resonators, and discloses a reflection structure of a plate wave resonator, which comprises: a piezoelectric insulator substrate, an interdigital transducer, and a reflection member; the reflecting component comprises a first reflecting electrode and a second reflecting electrode, wherein the first reflecting electrode is flush with the first edge of the piezoelectric insulator substrate, and the second reflecting electrode is flush with the second edge of the piezoelectric insulator substrate; the first reflection electrode and the second reflection electrode are both parallel to electrode fingers of the interdigital transducer; the widths of the first reflecting electrode and the second reflecting electrode are both lambda/8; the width of a gap between an electrode finger of the interdigital transducer adjacent to the first reflection electrode and the first reflection electrode is lambda/4; the width of the gap between the electrode finger of the interdigital transducer adjacent to the second reflection electrode and the second reflection electrode is λ/4. Such a reflection structure can cause evanescent interference, thereby reducing longitudinal noise of a plate wave resonator to which the reflection structure is applied. The application also discloses a plate wave resonator and a MEMS device.

Description

Reflection structure of plate wave resonator, and MEMS device
Technical Field
The present invention relates to the field of resonator technology, and for example, to a reflection structure of a plate wave resonator, and a Micro-Electro-Mechanical System (MEMS) device.
Background
At present, surface acoustic wave resonators and bulk acoustic wave resonators have been widely used in many fields, but the bandwidth, the electromechanical coupling coefficient and other properties of the two resonators gradually cannot meet the requirements of human beings. And the plate wave resonator with SH0 mode can obtain larger bandwidth and extremely high electromechanical coupling coefficient.
In the process of implementing the embodiments of the present disclosure, it is found that at least the following problems exist in the related art: the traditional reflection structure of the plate wave resonator is that an interdigital transducer is usually arranged on a substrate, and a gap of lambda/8 is left between the interdigital transducer and the edge of the substrate, and the longitudinal noise of the plate wave resonator with the traditional reflection structure is serious.
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 nor is intended to identify key/critical elements or to delineate the scope of such embodiments but rather as a prelude to the more detailed description that is presented later.
The embodiment of the disclosure provides a reflection structure of a plate wave resonator, the plate wave resonator and MEMS equipment, so as to reduce longitudinal clutter of the plate wave resonator.
In some embodiments, a reflective structure of a plate wave resonator, comprising: a piezoelectric insulator substrate having opposing first and second edges; an interdigital transducer and a reflecting component are arranged on the outer surface of the piezoelectric insulator substrate; the interdigital transducer is used for sound-electricity transduction and comprises a plurality of electrode fingers; the reflecting component comprises a first reflecting electrode and a second reflecting electrode, the first reflecting electrode is flush with the first edge, and the second reflecting electrode is flush with the second edge; the first reflection electrode and the second reflection electrode are both parallel to electrode fingers of the interdigital transducer; the widths of the first reflecting electrode and the second reflecting electrode are both lambda/8; the width of a gap between an electrode finger of the interdigital transducer adjacent to the first reflection electrode and the first reflection electrode is lambda/4; the width of a gap between an electrode finger of the interdigital transducer adjacent to the second reflection electrode and the second reflection electrode is lambda/4; λ is the wavelength of the plate wave resonator.
In some embodiments, each of the electrode fingers has a width of λ/4.
In some embodiments, the gap width between adjacent electrode fingers is λ/4.
In some embodiments, the interdigital transducer further comprises a first bus bar and a second bus bar; the first reflection electrode is connected to a first bus bar of the interdigital transducer or a second bus bar of the interdigital transducer.
In some embodiments, the second reflective electrode connects the first bus bar of the interdigital transducer or the second bus bar of the interdigital transducer.
In some embodiments, the piezoelectric insulator substrate is made of lithium niobate crystal, lithium tantalate crystal, aluminum nitride, zinc oxide, or piezoelectric ceramic.
In some embodiments, the first reflective electrode and the second reflective electrode are each made of aluminum, platinum, nickel, or molybdenum.
In some embodiments, a plate wave resonator includes a reflective structure as described above.
In some embodiments, a MEMS device includes a plate wave resonator as described above.
The reflection structure of the plate wave resonator, the plate wave resonator and the MEMS device provided by the embodiment of the disclosure can realize the following technical effects: the first reflecting electrode is arranged to be flush with the first edge of the piezoelectric insulator substrate, the second reflecting electrode is arranged to be flush with the second edge of the piezoelectric insulator substrate, and the widths of the first reflecting electrode and the second reflecting electrode are lambda/8. Such a reflection structure can cause evanescent interference, thereby reducing longitudinal noise of a plate wave resonator to which the reflection structure is applied.
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 in the accompanying drawings, which correspond to the accompanying drawings and not in limitation thereof, in which elements having the same reference numeral designations are shown as like elements and not in limitation thereof, and wherein:
FIG. 1 is a schematic structural diagram illustrating a top view of a reflective structure of a plate wave resonator in accordance with an embodiment of the present disclosure;
fig. 2 is a schematic structural diagram illustrating a top view of a reflective structure of another plate wave resonator provided by an embodiment of the present disclosure;
FIG. 3 is a schematic structural diagram of a plate wave resonator provided by an embodiment of the present disclosure;
FIG. 4 is a schematic top view of a conventional reflective structure;
FIG. 5 is a schematic diagram of the admittance response of a plate wave resonator with a conventional reflective structure provided by embodiments of the present disclosure;
FIG. 6 is a schematic diagram of the conductance response of a plate wave resonator having a conventional reflective structure provided by embodiments of the present disclosure;
FIG. 7 is a schematic illustration of the admittance response of a plate wave resonator having the reflective structure of the present application, as provided by an embodiment of the present disclosure;
fig. 8 is a schematic diagram of the conductance response of a plate wave resonator having the reflective structure of the present application provided by an embodiment of the present disclosure.
Reference numerals:
1: an interdigital transducer; 2: a first reflective electrode; 3: a second reflective electrode; 4: a piezoelectric insulator substrate; 5: a plate wave resonator input port; 6: and an output port of the plate wave resonator.
Detailed Description
So that the manner in which the features and elements of the disclosed embodiments can be understood in detail, a more particular description of the disclosed embodiments, briefly summarized above, may be had by reference to the embodiments, some of which are illustrated in the appended drawings. 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 be practiced without these details. In other instances, well-known structures and devices may be shown in simplified form in order to simplify the drawing.
The terms "first," "second," and the like in the description and in the claims, and the above-described drawings of embodiments of the present disclosure, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It should be understood that the data so used may be interchanged under appropriate circumstances such that embodiments of the present disclosure described herein may be made. Furthermore, the terms "comprising" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions.
In the embodiments of the present disclosure, the terms "upper", "lower", "inner", "middle", "outer", "front", "rear", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings. These terms are used primarily to better describe the disclosed embodiments and their examples and are not intended to limit the indicated devices, elements or components to a particular orientation or to be constructed and operated in a particular orientation. Moreover, some of the above terms may be used to indicate other meanings besides the orientation or positional relationship, for example, the term "on" may also be used to indicate some kind of attachment or connection relationship in some cases. The specific meanings of these terms in the embodiments of the present disclosure can be understood by those of ordinary skill in the art as appropriate.
In addition, the terms "disposed," "connected," and "secured" are to be construed broadly. For example, "connected" may be a fixed connection, a detachable connection, or a unitary construction; can 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. Specific meanings of the above terms in the embodiments of the present disclosure can be understood by those of ordinary skill in the art according to specific situations.
The term "plurality" means two or more unless otherwise specified.
In the embodiment of the present disclosure, the character "/" indicates that the preceding and following objects are in an or relationship. For example, A/B represents: a or B.
The term "and/or" is an associative relationship that describes objects, meaning that three relationships may exist. For example, a and/or B, represents: a or B, or A and B.
It should be noted that, in the case of no conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other.
Referring to fig. 1, an embodiment of the present disclosure provides a reflection structure of a plate wave resonator, where the reflection structure of the plate wave resonator includes: a piezoelectric insulator substrate 4, an interdigital transducer 1, and a reflection member; a piezoelectric insulator substrate 4 having opposite first and second edges; the interdigital transducer 1 and the reflection member are arranged on the outer surface of the piezoelectric insulator substrate 4; the interdigital transducer 1 is used for sound-electricity transduction and comprises a plurality of electrode fingers; the reflecting component comprises a first reflecting electrode 2 and a second reflecting electrode 3, wherein the first reflecting electrode 2 is flush with the first edge, and the second reflecting electrode 3 is flush with the second edge; the first reflection electrode 2 and the second reflection electrode 3 are both parallel to the electrode fingers of the interdigital transducer 1; the widths of the first reflective electrode 2 and the second reflective electrode 3 are both lambda/8; the gap width between the electrode finger of the interdigital transducer 1 adjacent to the first reflection electrode 2 and the first reflection electrode 2 is λ/4; the gap width between the electrode finger of the interdigital transducer 1 adjacent to the second reflection electrode 3 and the second reflection electrode 3 is λ/4; λ is the wavelength of the plate wave resonator.
By adopting the reflection structure of the plate wave resonator provided by the embodiment of the disclosure, the reflection structure is provided with a piezoelectric insulator substrate, an interdigital transducer and a reflection component; wherein the piezoelectric insulator substrate has a first edge and a second edge opposite to each other; an interdigital transducer and a reflecting component are arranged on the outer surface of the piezoelectric insulator substrate; the interdigital transducer is used for sound-electricity transduction and comprises a plurality of electrode fingers; a reflective member including a first reflective electrode and a second reflective electrode, the first reflective electrode being flush with the first edge, the second reflective electrode being flush with the second edge; the first reflection electrode and the second reflection electrode are both parallel to electrode fingers of the interdigital transducer; the widths of the first reflecting electrode and the second reflecting electrode are both lambda/8; the width of a gap between an electrode finger of the interdigital transducer adjacent to the first reflection electrode and the first reflection electrode is lambda/4; the width of a gap between the electrode finger of the interdigital transducer adjacent to the second reflection electrode and the second reflection electrode is lambda/4; λ is the wavelength of the plate wave resonator. Such a reflection structure can cause evanescent interference, thereby reducing longitudinal noise of a plate wave resonator to which the reflection structure is applied.
As shown in fig. 1, the reflection structure of the plate wave resonator further includes: a plate wave resonator input port 5 and a plate wave resonator output port 6; the plate wave resonator input port 5 and the plate wave resonator output port 6 are both connected with an interdigital transducer. And the input port of the plate wave resonator and the output port of the plate wave resonator are both used for being connected with a peripheral circuit.
Optionally, each electrode finger of the interdigital transducer has a width of λ/4.
Optionally, the gap width between adjacent electrode fingers of the interdigital transducer is λ/4.
Optionally, the interdigital transducer further comprises a first bus bar and a second bus bar; the first reflection electrode is connected to the first bus bar of the interdigital transducer or the second bus bar of the interdigital transducer.
Optionally, the second reflective electrode connects the first bus bar of the interdigital transducer or the second bus bar of the interdigital transducer.
In some embodiments, as shown in fig. 2, a reflection structure of a plate wave resonator includes: a piezoelectric insulator substrate 4, an interdigital transducer 1, a plate wave resonator input port 5, a plate wave resonator output port 6, and a reflection member. A piezoelectric insulator substrate 4 having opposite first and second edges; the interdigital transducer 1 and the reflection member are disposed on the outer surface of the piezoelectric insulator substrate 4; the interdigital transducer 1 is used for sound-electricity transduction and comprises a plurality of electrode fingers, a first bus bar and a second bus bar; the reflecting component comprises a first reflecting electrode 2 and a second reflecting electrode 3, wherein the first reflecting electrode 2 is flush with the first edge, and the second reflecting electrode 3 is flush with the second edge; the first reflection electrode 2 and the second reflection electrode 3 are both parallel to the electrode fingers of the interdigital transducer 1; the widths of the first reflective electrode 2 and the second reflective electrode 3 are both lambda/8; the gap width between the electrode finger of the interdigital transducer 1 adjacent to the first reflection electrode 2 and the first reflection electrode 2 is λ/4; the gap width between the electrode finger of the interdigital transducer 1 adjacent to the second reflection electrode 3 and the second reflection electrode 3 is λ/4. The first reflection electrode 2 is connected with a first bus bar of the interdigital transducer 1, and the second reflection electrode 3 is connected with a second bus bar of the interdigital transducer 1; the plate wave resonator input port 5 and the plate wave resonator output port 6 are both connected with the interdigital transducer 1 and are used for being connected with peripheral circuits. Such a reflection structure can cause evanescent interference, thereby reducing longitudinal noise of a plate wave resonator to which the reflection structure is applied.
Alternatively, the piezoelectric insulator substrate is made of lithium niobate crystal, lithium tantalate crystal, aluminum nitride, zinc oxide, or piezoelectric ceramic.
Optionally, the electrode fingers of the interdigital transducer are made of aluminum, platinum, nickel, or molybdenum.
Optionally, the first reflective electrode and the second reflective electrode are both made of aluminum, platinum, nickel, or molybdenum.
In some embodiments, the piezoelectric insulator substrate is obtained from a lithium niobate crystal having piezoelectric properties with a thickness of 10 nm to 10 μm by a sputtering or wafer bonding process. The method comprises the steps of obtaining a metal film layer on a piezoelectric insulator substrate by using an evaporation or sputtering process, photoetching the metal film layer, and processing the metal film layer by using a stripping process or an etching process to obtain a first bus bar, a second bus bar, an electrode finger, a first reflection electrode and a second reflection electrode of the interdigital transducer.
In some embodiments, the reflection structure of the plate wave resonator proposed by the present scheme can be applied to 5 types of plate wave resonators, and fig. 3 is a schematic structural diagram of the plate wave resonator, where (1) is a plate wave resonator having a single-layer electrode IDT (Interdigital transducer), (2) is a plate wave resonator having a suspended electrode IDT, (3) is a plate wave resonator having an electrode grounded IDT, (4) is a plate wave resonator having a double-layer in-phase electrode IDT, and (5) is a plate wave resonator having a double-layer opposite-phase electrode IDT.
In some embodiments, the SAW (Surface acoustic wave) resonator uses Surface acoustic rayleigh waves or Surface acoustic shear waves that are neither dispersive. PAW (Plate acoustic wave) has two types of resonance modes, one being lamb waves with longitudinal and shear perpendicular components, such as: s0, a0, S1, a1, or the like, and the other is an SH horizontal plate wave having a shear horizontal component, for example: SH0 or SH1, etc., and all PAW resonance modes have dispersion characteristics; SAW resonators are mainly applied to filters, while PAW resonators are generally applied to the fields of oscillators, microphones, sensors and the like due to the characteristics of large bandwidth and low loss. Meanwhile, the longitudinal noise problem existing in the PAW resonator does not exist in the SAW resonator.
In some embodiments, SH0 mode PAW resonators based on piezoelectric transduction materials such as lithium niobate, lithium tantalate, etc. can achieve large bandwidths and extremely high electromechanical coupling coefficients, and exhibit slower spurious responses. PAW uses an interdigital transducer to effectively excite the SH0 slab mode, thereby converting the electrical signal into mechanical vibration of the piezoelectric material.
In some embodiments, the IDT is composed of a piezoelectric material, a wafer substrate, a bus bar and a plurality of electrode fingers, and it is generally necessary to optimize the performance thereof by adjusting parameters such as the electrode index NE, the device length L, the electrode coverage η, the end-to-end spacing gap-end, and the like. The distance between the electrode finger of the interdigital transducer which is parallel to the edge of the substrate and adjacent to the edge of the substrate and the edge of the substrate is called as an end distance; however, increasing the electrode index NE results in more spurious modes occurring in a smaller frequency range; the adjustment efficiency for adjusting the length L of the device is low, and the frequency drift is difficult to predict; if the frequency is selected by adjusting the electrode coverage η, it is very sensitive to the electrode material and thickness. Thus, the end-to-end gap is selected to be off. In the IDT of the conventional reflection structure, in order to match the maximum values of the electrode potential and displacement with the electrode pitch of the IDT, the gap-end is set to λ/8. However, the longitudinal noise of the resonator having the conventional reflection structure is serious. According to the scheme, the first reflecting electrode is arranged to be flush with the first edge of the piezoelectric insulator substrate, the second reflecting electrode is arranged to be flush with the second edge of the piezoelectric insulator substrate, and the widths of the first reflecting electrode and the second reflecting electrode are lambda/8. Such a reflection structure can cause evanescent interference, thereby reducing longitudinal noise of a plate wave resonator to which the reflection structure is applied.
The embodiment of the present disclosure provides a plate wave resonator, including above-mentioned reflecting structure, the reflecting structure includes: a piezoelectric insulator substrate, an interdigital transducer, and a reflection member; a piezoelectric insulator substrate having opposing first and second edges; an interdigital transducer and a reflecting component are arranged on the outer surface of the piezoelectric insulator substrate; the interdigital transducer is used for sound-electricity transduction and comprises a plurality of electrode fingers; a reflective member including a first reflective electrode and a second reflective electrode, the first reflective electrode being flush with the first edge, the second reflective electrode being flush with the second edge; the first reflection electrode and the second reflection electrode are both parallel to electrode fingers of the interdigital transducer; the widths of the first reflecting electrode and the second reflecting electrode are both lambda/8; the width of a gap between an electrode finger of the interdigital transducer adjacent to the first reflection electrode and the first reflection electrode is lambda/4; the width of a gap between the electrode finger of the interdigital transducer adjacent to the second reflection electrode and the second reflection electrode is lambda/4; λ is the wavelength of the plate wave resonator.
By adopting the plate wave resonator provided by the embodiment of the disclosure, the first reflecting electrode is arranged to be flush with the first edge of the piezoelectric insulator substrate, the second reflecting electrode is arranged to be flush with the second edge of the piezoelectric insulator substrate, and the widths of the first reflecting electrode and the second reflecting electrode are both lambda/8. Such a reflection structure can cause evanescent interference, thereby reducing longitudinal noise of a plate wave resonator to which the reflection structure is applied.
Optionally, each electrode finger has a width of λ/4.
Optionally, the gap width between each adjacent electrode finger is λ/4.
Optionally, the interdigital transducer further comprises a first bus bar and a second bus bar; the first reflection electrode is connected to the first bus bar of the interdigital transducer or the second bus bar of the interdigital transducer.
Optionally, the second reflective electrode connects the first bus bar of the interdigital transducer or the second bus bar of the interdigital transducer.
In some embodiments, the plate wave resonator input port is connected to the second bus bar of the interdigital transducer and the plate wave resonator output port is connected to the first bus bar of the interdigital transducer. The voltage of the input port of the plate wave resonator and the voltage of the output port of the plate wave resonator have a voltage difference.
Alternatively, the piezoelectric insulator substrate is made of lithium niobate crystal, lithium tantalate crystal, aluminum nitride, zinc oxide, or piezoelectric ceramic.
Optionally, the first reflective electrode and the second reflective electrode are both made of aluminum, platinum, nickel, or molybdenum.
In some embodiments, fig. 4 is a schematic diagram of a conventional reflective structure, and as shown in fig. 4, another conventional reflective structure includes a substrate having a first edge and a second edge opposite to each other, interdigital transducers are disposed on the substrate, electrode fingers of the interdigital transducers adjacent to the first edge of the substrate are spaced from the first edge of the substrate by λ/8, electrode fingers of the interdigital transducers adjacent to the second edge of the substrate are spaced from the second edge of the substrate by λ/8, and the conventional reflective structure is further provided with an input port and an output port connected to a peripheral circuit.
Thus, the plate wave resonator having the conventional reflection structure uses the free edge instead of the large number of grating reflection structures. However, basic flat-panel modalities, such as: s0, a0, SH0, and the like, there is no mode conversion at the edge of the void, resulting in severe longitudinal noise of the plate wave resonator having the conventional reflection structure. The reflecting structure of the application has the advantages that the width of the first reflecting electrode and the width of the second reflecting electrode are designed to be lambda/8, so that the process is simple and convenient, and longitudinal noise waves reflected by free edges can be effectively inhibited or even eliminated.
In some embodiments, in a case where a plate wave resonator including a substrate made of lithium niobate of 30 ° YX and having a thickness of 0.1 wavelength and an IDT having a thickness of 4% wavelength, where the wavelength is 1 μm, is used with the conventional reflection structure of fig. 4, a schematic diagram of an admittance response of the plate wave resonator having the conventional reflection structure as shown in fig. 5 and a schematic diagram of a conductance response of the plate wave resonator having the conventional reflection structure as shown in fig. 6 are obtained, in fig. 5, the abscissa represents frequency and the ordinate represents admittance, and curve a is an admittance frequency response curve of the plate wave resonator having the conventional reflection structure. In fig. 6, the abscissa represents frequency, the ordinate represents conductance, and curve B is a conductance frequency response curve of a plate wave resonator having a conventional reflection structure. In the case where the reflection structure of the present application is applied to the plate wave resonator, a schematic diagram of the admittance response of the plate wave resonator having the reflection structure of the present application as shown in fig. 7 and a schematic diagram of the conductance response of the plate wave resonator having the reflection structure of the present application as shown in fig. 8 are obtained, in fig. 7, the abscissa represents the frequency and the ordinate represents the admittance, where curve C is the admittance frequency response curve of the plate wave resonator having the reflection structure of the present application. In fig. 8, the abscissa represents frequency, the ordinate represents conductance, and a curve D is a conductance frequency response curve of the plate wave resonator having the reflection structure of the present application. As shown in fig. 7 and 8, the admittance and conductance response diagrams of the slab wave resonator with the reflective structure of the present application are very clean, since reflection occurs at the negative maximum displacement point, whereas the reflective structure of the present application is equivalent to an infinite propagation path without bounce points. Meanwhile, as can be seen from fig. 7 and 8, the longitudinal mode of the frequency response curve is smoother, and the longitudinal clutter is also completely eliminated. Meanwhile, the reflection structure can obtain larger bandwidth, the fluctuation in the pass band is reduced, and the loss in the pass band is reduced, so that higher precision and sensitivity can be obtained. The plate wave resonator with the novel reflection structure is applied to MEMS equipment, and the performance of the MEMS equipment can be improved.
The embodiment of the present disclosure provides an MEMS device, including above-mentioned acoustic wave resonator, the acoustic wave resonator includes above-mentioned reflection configuration, and the reflection configuration includes: a piezoelectric insulator substrate, an interdigital transducer, and a reflection member; a piezoelectric insulator substrate having opposing first and second edges; an interdigital transducer and a reflecting component are arranged on the outer surface of the piezoelectric insulator substrate; the interdigital transducer is used for sound-electricity transduction and comprises a plurality of electrode fingers; a reflective member including a first reflective electrode and a second reflective electrode, the first reflective electrode being flush with the first edge, the second reflective electrode being flush with the second edge; the first reflection electrode and the second reflection electrode are both parallel to electrode fingers of the interdigital transducer; the widths of the first reflecting electrode and the second reflecting electrode are both lambda/8; the width of a gap between an electrode finger of the interdigital transducer adjacent to the first reflection electrode and the first reflection electrode is lambda/4; the width of a gap between the electrode finger of the interdigital transducer adjacent to the second reflection electrode and the second reflection electrode is lambda/4; λ is the wavelength of the plate wave resonator.
Optionally, the MEMS device comprises a liquid level sensor, an oscillator, a microphone, a radio frequency switch or a filter.
By adopting the MEMS device provided by the embodiment of the disclosure, the first reflecting electrode is arranged to be flush with the first edge of the piezoelectric insulator substrate, the second reflecting electrode is arranged to be flush with the second edge of the piezoelectric insulator substrate, and the widths of the first reflecting electrode and the second reflecting electrode are both lambda/8. Such a reflection structure can cause evanescent interference, thereby reducing longitudinal noise of a plate wave resonator to which the reflection structure is applied. Accordingly, the performance of a MEMS device using such an acoustic wave resonator can be improved.
The above description and drawings sufficiently illustrate embodiments of the disclosure to enable those skilled in the art to practice them. Other embodiments may include structural and other changes. The examples merely typify 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. The embodiments of the present disclosure are not limited to the structures that have been described above and shown in the drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims (10)

1. A reflection structure of a plate wave resonator, comprising:
a piezoelectric insulator substrate having opposing first and second edges; an interdigital transducer and a reflecting component are arranged on the outer surface of the piezoelectric insulator substrate;
the interdigital transducer is used for sound-electricity transduction and comprises a plurality of electrode fingers;
the reflecting component comprises a first reflecting electrode and a second reflecting electrode, the first reflecting electrode is flush with the first edge, and the second reflecting electrode is flush with the second edge; the first reflection electrode and the second reflection electrode are both parallel to electrode fingers of the interdigital transducer; the widths of the first reflecting electrode and the second reflecting electrode are both lambda/8; the width of a gap between an electrode finger of the interdigital transducer adjacent to the first reflection electrode and the first reflection electrode is lambda/4; the width of a gap between an electrode finger of the interdigital transducer adjacent to the second reflection electrode and the second reflection electrode is lambda/4; λ is the wavelength of the plate wave resonator.
2. The reflective structure of claim 1 wherein each of said electrode fingers has a width of λ/4.
3. The reflective structure of claim 2, wherein the gap width between adjacent electrode fingers is λ/4.
4. The reflective structure according to any one of claims 1 to 3, wherein the interdigital transducer further comprises a first bus bar and a second bus bar;
the first reflection electrode is connected to a first bus bar of the interdigital transducer or a second bus bar of the interdigital transducer.
5. The reflective structure of claim 4 wherein the second reflective electrode connects the first bus bar of the interdigital transducer or the second bus bar of the interdigital transducer.
6. The reflective structure according to claim 5, wherein said piezoelectric insulator substrate is made of lithium niobate crystal, lithium tantalate crystal, aluminum nitride, zinc oxide, or piezoelectric ceramic.
7. The reflective structure according to claim 5, wherein said first reflective electrode and said second reflective electrode are each made of aluminum, platinum, nickel or molybdenum.
8. A plate wave resonator comprising a reflective structure according to any of claims 1 to 7.
9. A MEMS device, comprising the plate wave resonator of claim 8.
10. The MEMS device, as recited in claim 9, wherein the MEMS device comprises a level sensor, an oscillator, a microphone, a radio frequency switch, or a filter.
CN202111234538.5A 2021-10-14 2021-10-22 Reflection structure of plate wave resonator, and MEMS device Pending CN113992178A (en)

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CN2021111991101 2021-10-14

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