WO2024152737A1 - 谐振器、滤波器、电子设备 - Google Patents

谐振器、滤波器、电子设备 Download PDF

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Publication number
WO2024152737A1
WO2024152737A1 PCT/CN2023/133797 CN2023133797W WO2024152737A1 WO 2024152737 A1 WO2024152737 A1 WO 2024152737A1 CN 2023133797 W CN2023133797 W CN 2023133797W WO 2024152737 A1 WO2024152737 A1 WO 2024152737A1
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Prior art keywords
electrodes
electrode
resonator
interdigitated
coupling coefficient
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PCT/CN2023/133797
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English (en)
French (fr)
Inventor
张乃卿
普莱斯基维克托
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华为技术有限公司
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Publication of WO2024152737A1 publication Critical patent/WO2024152737A1/zh

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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
    • 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
    • H03H9/13—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials
    • 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
    • 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
    • H03H9/21—Crystal tuning forks
    • H03H9/215—Crystal tuning forks consisting of quartz
    • 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
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/70—Multiple-port networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source

Definitions

  • the present application relates to the technical field of resonators, and in particular to a resonator, a filter having a resonator, and an electronic device including the filter or the resonator.
  • BAW resonators such as horizontally-excited Bulk Acoustic Resonator (XBAR), vertically-excited Bulk Acoustic Resonator (YBAR), and film bulk acoustic resonator (FBAR) have attracted wide attention.
  • XBAR horizontally-excited Bulk Acoustic Resonator
  • YBAR vertically-excited Bulk Acoustic Resonator
  • FBAR film bulk acoustic resonator
  • YBAR has a larger electromechanical coupling coefficient and a more efficient resonant mode, and can be used in a larger passband bandwidth, for example, it can meet the passband bandwidth of the Sub-6GHz frequency band.
  • heterodyne modes appear near the resonant frequency and anti-resonant frequency range of the YBAR. These heterodyne modes interfere with the main resonant mode to a great extent, causing many problems for the performance of the resonator and the filter. For example, these heterodyne modes will increase the passband ripple of the filter and deteriorate the out-of-band suppression performance.
  • the present application provides a resonator, a filter having the resonator, and an electronic device including the filter.
  • the main purpose is to provide a resonator that not only has a large electromechanical coupling coefficient but can also effectively suppress parasitic heterogeneous modes.
  • the present application provides a resonator.
  • the resonator may be an acoustic wave resonator, such as a YBAR.
  • the resonator includes a substrate, a first electrode, a piezoelectric layer and a plurality of second electrodes, the plurality of second electrodes are arranged side by side in a first direction, the piezoelectric layer has a first side and a second side, the plurality of second electrodes are located on the first side, and the first electrode and the substrate are located on the second side; that is, the piezoelectric layer is stacked between the first electrode and the second electrode, so that the piezoelectric layer is excited to resonate by using the vertical electric field formed between the first electrode and the second electrode, for example, forming YBAR; in addition, in the resonator of the present application, the piezoelectric layer includes a piezoelectric material, and the crystal cutting angle and propagation direction of the piezoelectric material are X-cut, (120° ⁇ 30°)Y propagation direction , or, the Euler angles of the piezoelectric material crystal are (90°, 90°, 120° ⁇ 30°), wherein the X direction of
  • the crystal cutting angle and propagation direction of the piezoelectric material can be X-cut, (120° ⁇ 30°)Y propagation direction, that is, the Euler angle can be (90°, 90°, 120° ⁇ 30°), or, the crystal cutting angle and propagation direction can be Y-cut, (90° ⁇ 30°)X propagation direction, that is, the Euler angle can be (0°, 90°, 90° ⁇ 30°).
  • the resonator can have a larger electromechanical coupling coefficient, for example, the electromechanical coupling coefficient can be greater than 40%.
  • the electromechanical coupling coefficient component k 35 2 > 0.4, which can excite a first-order antisymmetric A1 main resonance mode.
  • a first gap between two adjacent second electrodes there is a first gap between two adjacent second electrodes; a first groove is provided at a position of the piezoelectric layer opposite to the first gap, and the first groove is connected to the first gap.
  • the grooves are formed in the piezoelectric layer, the grooves help to further suppress or frequency-shift the parasitic mode and increase the electromechanical coupling coefficient of the resonator.
  • the piezoelectric layer has a bottom surface located on the second side and a top surface located on the first side, and the first groove runs through the bottom surface and the top surface.
  • the electromechanical coupling coefficient can be further increased.
  • the radial dimension of the first groove gradually increases from the top surface to the bottom surface.
  • the inclination angle ⁇ of the side surface of the first groove satisfies: 45° ⁇ 90°; or, 60° ⁇ 90°.
  • the wave resonator further comprises a protective layer, and a surface of the second electrode away from the piezoelectric layer, a side surface of the first gap, and a side surface and a bottom surface of the first groove are all covered by the protective layer.
  • the protective layer can protect the resonator from corrosion, scratches, oxidation, etc., and protect the performance of the device.
  • the protective layer can also adjust the resonant frequency of the resonator, and can also adjust the electromechanical coupling coefficient and temperature coefficient of frequency (TCF) of the resonator.
  • the first electrode has a first surface and a second surface relative to each other, the first surface being closer to the piezoelectric layer than the second surface; the substrate is provided with a cavity, at least a portion of the second surface of the first electrode is used to enclose the cavity, and at least a portion of the first electrode is arranged between the cavity and the piezoelectric layer.
  • the electromechanical coupling coefficient K t 2 of the resonator is ⁇ 20%.
  • the resonator formed in this way can be called a cavity-type suspension resonator.
  • the electromechanical coupling coefficient component k 35 2 > 0.4 the electromechanical coupling coefficient of the resonator can reach more than 20%.
  • the electromechanical coupling coefficient of the resonator can be further increased.
  • the first electrode has a first surface and a second surface opposite to each other, the first surface is closer to the piezoelectric layer than the second surface; the first electrode is disposed between the substrate and the piezoelectric layer, and the second surface of the first electrode is completely disposed on the substrate.
  • the electromechanical coupling coefficient K t 2 of the resonator is ⁇ 10%.
  • the resonator formed in this way can be called a solid substrate resonator.
  • the electromechanical coupling coefficient component k 35 2 > 0.4 the electromechanical coupling coefficient of the resonator can reach more than 10%.
  • the resonator further includes: the resonator further includes: a first bus bar and a second bus bar; one of each two adjacent second electrodes in a plurality of second electrodes is a first interdigitated electrode, and the other is a second interdigitated electrode, the first interdigitated electrode and the second interdigitated electrode are spaced in a first direction, and the extension direction of the first interdigitated electrode and/or the second interdigitated electrode is perpendicular to the first direction; a plurality of first interdigitated electrodes in the plurality of second electrodes are connected through the first bus bar, and a plurality of second interdigitated electrodes in the plurality of second electrodes are connected through the second bus bar; the finger spacing P satisfies: Wherein: Vs is the shear wave velocity of the substrate, f is the operating frequency of the resonator; the width dimension of each first interdigitated electrode is s1, the spacing between each two adjacent first interdigitated electrodes and
  • the finger spacing P satisfies:
  • the piezoelectric layer is connected to the substrate layer, the energy can be prevented from leaking from the piezoelectric layer to the substrate layer, so as to improve the quality factor Q value and the electromechanical coupling coefficient.
  • the substrate includes at least one of silicon carbide, boron nitride, and diamond.
  • the thickness dimension Z of the substrate satisfies: Z ⁇ 4d, d is the thickness dimension of the piezoelectric layer, and the thickness dimension of the substrate and the thickness dimension of the piezoelectric layer are both dimensions in a direction perpendicular to the surface of the substrate.
  • the solid-state substrate resonator further includes a stacked first reflection layer and a second reflection layer; the first reflection layer and the second reflection layer are arranged between the substrate and the first electrode; wherein the thickness t1 of the first reflection layer satisfies: The thickness t2 of the second reflective layer satisfies: Wherein, ⁇ 1 is the wavelength of the sound wave of the resonator at the resonant frequency in the first reflective layer material, and ⁇ 2 is the wavelength of the sound wave in the second reflective layer material.
  • the stacked first reflective layer and the second reflective layer may be regarded as a group, and in some examples, three to ten groups may be provided.
  • the electromechanical coupling coefficient can be further improved.
  • the electromechanical coupling coefficient of the resonator can be further increased, for example, the electromechanical coupling coefficient of the resonator can reach 45%.
  • the resonator further includes a conductive connection layer; the conductive connection layer is stacked between the first electrode and the piezoelectric layer.
  • connection strength between the first electrode and the piezoelectric layer can be increased, thereby avoiding the poor adhesion between the layers and affecting the robustness of the device due to the mismatch between the lattice of the first electrode and the lattice of the piezoelectric layer.
  • At least some of the plurality of second electrodes include a first end and a second end, a thickness dimension D1 of the first end is greater than a thickness dimension D2 of the second end, and 120% ⁇ D1/D2 ⁇ 300%.
  • At least part of the plurality of second electrodes include a first end and a second end, wherein a width dimension h1 of the first end is greater than a width dimension h2 of the second end; and 100% ⁇ h1/h2 ⁇ 200%; the width dimension is a dimension perpendicular to an extension direction of the second electrode.
  • the transverse mode can be suppressed similarly.
  • the resonator further includes: a first bus bar and a second bus bar; one of each two adjacent second electrodes among the plurality of second electrodes is a first interdigitated electrode, and the other is a second interdigitated electrode, the first interdigitated electrode and the second interdigitated electrode are spaced apart in a first direction, and an extension direction of the first interdigitated electrode and/or the second interdigitated electrode is perpendicular to the first direction; a plurality of first interdigitated electrodes among the plurality of second electrodes are connected via the first bus bar, and a plurality of second interdigitated electrodes among the plurality of second electrodes are connected via the second bus bar; an end of the first interdigitated electrode connected to the first bus bar is a finger connection end, and the other end is a finger tip, and a second gap is provided between the finger tip and the second bus bar; a second groove is provided at a position of the piezoelectric layer opposite to the second gap, and the second groove is connected to the second gap.
  • the resonator further comprises a plurality of grid bars arranged in parallel, one end of the plurality of grid bars are connected by a first connecting bar, the other ends of the plurality of grid bars are connected by a second connecting bar, and an extension direction of the grid bars is the same as an extension direction of the second electrode;
  • One of every two adjacent second electrodes among the multiple second electrodes is a first interdigitated electrode, and the other is a second interdigitated electrode, the first interdigitated electrode and the second interdigitated electrode are spaced in a first direction, and the extension direction of the first interdigitated electrode and/or the second interdigitated electrode is perpendicular to the first direction;
  • the multiple first interdigitated electrodes among the multiple second electrodes are connected by a first bus bar, and the multiple second interdigitated electrodes among the multiple second electrodes are connected by a second bus bar;
  • the spacing t between two adjacent grid bars satisfies: 0.3 ⁇ t/P ⁇ 0.7;
  • P is the finger spacing, the width dimension of each first
  • the reflection grating can reflect the acoustic energy propagating outward, concentrate the energy of the resonator in the area of the resonator with the second electrode, and improve the quality factor Q of the device.
  • the piezoelectric layer includes a first side wall and a second side wall that are opposite to each other; the first side wall and/or the second side wall is a plane that is perpendicular to the substrate surface and parallel to the extension direction of the second electrode.
  • the first side wall and the second side wall can reflect the acoustic energy propagating outward, concentrate the energy of the resonator in the area of the resonator having the second electrode, and improve the quality factor Q of the device.
  • the material of the piezoelectric layer includes at least one of a combination of niobium and lithium and a combination of tantalum and lithium; and the material of the first electrode includes at least one of tungsten, platinum, molybdenum, and aluminum.
  • the material of the piezoelectric layer includes at least one of lithium niobate and lithium tantalate.
  • the value of the electromechanical coupling coefficient component k 35 2 is the maximum value among multiple electromechanical coupling coefficient component values.
  • the electromechanical coupling coefficient component k 35 2 can reach 0.9253.
  • 0.4 ⁇ k 35 2 or 0.4 ⁇ k 35 2 ⁇ 0.95, or 0.4 ⁇ k 35 2 ⁇ 0.9253.
  • the resonator is used to generate a first-order antisymmetric mode when exciting the electromechanical coupling coefficient component k 35 2 of the piezoelectric material, wherein the vibration direction of the first-order antisymmetric mode is parallel to the surface of the substrate and perpendicular to the extension direction of the second electrodes.
  • the first-order antisymmetric A1 mode is the main resonant mode of the resonator.
  • the resonator is used to excite an electric field of at least part of the electromechanical coupling coefficient component other than the electromechanical coupling coefficient component k 35 2 parallel to the extension direction of the second electrode; at least part of the electromechanical coupling coefficient component includes: at least one of the electromechanical coupling coefficient components k 21 2 , k 22 2 , k 23 2 , k 24 2 , k 25 2 and k 26 2 .
  • the electric field that excites the electromechanical coupling coefficient components k212 , k222 , k232 , k242, k252 and k262 is along the extension direction of the second electrode, the electric field strength in this direction is substantially zero , thereby causing these electromechanical coupling coefficient components to produce smaller parasitic modes.
  • the present application also provides a resonator.
  • the resonator includes a first electrode, a piezoelectric layer and a plurality of second electrodes, the plurality of second electrodes are arranged side by side, the piezoelectric layer has a first side and a second side, the plurality of second electrodes are located on the first side, and the first electrode and the substrate are located on the second side; that is, the first electrode and the second electrode are located on opposite sides of the piezoelectric layer, so that the piezoelectric layer is excited by a vertical electric field to generate resonance, for example, to form a YBAR; in addition, in the resonator of the present application, the piezoelectric layer includes a piezoelectric material, and the value of the electromechanical coupling coefficient component k 35 2 of the piezoelectric material satisfies: k 35 2 >0.4.
  • the value of the electromechanical coupling coefficient component k 35 2 of the piezoelectric material satisfies: k 35 2 >0.4.
  • the Euler angle of the piezoelectric material is (90°, 90°, 120° ⁇ 30°), or the Euler angle is (0°, 90°, 90° ⁇ 30°).
  • the electromechanical coupling coefficient component k 35 2 of the resonator can reach a larger value, so that the resonator has a larger electromechanical coupling coefficient, for example, the electromechanical coupling coefficient can be greater than 40%.
  • electromechanical coupling coefficient components k 21 2 , k 22 2 , k 23 2 , k 24 2 , k 25 2 and k 26 2 with larger values other than the electromechanical coupling coefficient component k 35 2 have electric field directions that are parallel to the extension direction of the second electrode, and the electric potentials along the extension direction of the second electrode are the same on the second electrode, and the electric field strength is zero. Therefore, these electromechanical coupling coefficient components k 21 2 , k 22 2 , k 23 2 , k 24 2 , k 25 2 and k 26 2 cause smaller parasitic modes, so that the resonator has a larger electromechanical coupling coefficient and the parasitic modes are effectively suppressed.
  • the piezoelectric material has a plurality of electromechanical coupling coefficient components, and the value of the electromechanical coupling coefficient component k 35 2 is the maximum value among the plurality of electromechanical coupling coefficient component values.
  • 0.4 ⁇ k 35 2 or 0.4 ⁇ k 35 2 ⁇ 0.95, or 0.4 ⁇ k 35 2 ⁇ 0.9253.
  • the resonator is used to generate a first-order antisymmetric mode when exciting the electromechanical coupling coefficient component k 35 2 of the piezoelectric material, wherein the vibration direction of the first-order antisymmetric mode is parallel to the surface of the substrate and perpendicular to the extension direction of the second electrodes.
  • the first-order antisymmetric A1 mode is the main resonant mode of the resonator.
  • the resonator is used to excite an electric field of at least part of the electromechanical coupling coefficient component other than the electromechanical coupling coefficient component k 35 2 parallel to the extension direction of the second electrode; at least part of the electromechanical coupling coefficient component includes: at least one of the electromechanical coupling coefficient components k 21 2 , k 22 2 , k 23 2 , k 24 2 , k 25 2 and k 26 2 .
  • the electric field that excites the electromechanical coupling coefficient components k212 , k222 , k232 , k242, k252 and k262 is along the extension direction of the second electrode, the electric field strength in this direction is substantially zero , thereby causing these electromechanical coupling coefficient components to produce smaller parasitic modes.
  • the present application also provides a method for preparing a resonator, the method comprising:
  • a first electrode, a piezoelectric layer and a plurality of second electrodes are prepared, wherein the piezoelectric layer has a first side and a second side, the plurality of second electrodes are located on the first side, the first electrode and the substrate are located on the second side, and the plurality of second electrodes are arranged side by side in a first direction;
  • the crystal cutting angle and propagation direction of the piezoelectric material of the piezoelectric layer are X-cut, (120° ⁇ 30°)Y propagation direction, or, the Euler angle of the crystal of the piezoelectric material is (90°, 90°, 120° ⁇ 30°), the X direction of the piezoelectric material is in the same direction as the thickness direction of the piezoelectric layer, and the Y direction of the piezoelectric material (120° ⁇ 30°) is in the same direction as the first direction, or;
  • the crystal cutting angle and propagation direction of the piezoelectric material are Y-cut, (90° ⁇ 30°)X propagation direction, or the crystal Euler angle of the piezoelectric material is (0°, 90°, 90° ⁇ 30°), the Y direction of the piezoelectric material is in the same direction as the thickness direction of the piezoelectric layer, and the (90° ⁇ 30°)X direction of the piezoelectric material is in the same direction as the first direction.
  • the resonator manufactured by the preparation method provided in the present application can have a larger electromechanical coupling coefficient, for example, the electromechanical coupling coefficient can be greater than 40%, under the Euler angle limitation of the piezoelectric material crystal. Moreover, when the crystal is at this Euler angle, the electromechanical coupling coefficient components k 21 2 , k 22 2 , k 23 2 , k 24 2 , k 25 2 and k 26 2 with larger values other than the electromechanical coupling coefficient component k 35 2 have electric field directions that excite these electromechanical coupling coefficient components that are parallel to the extension direction of the second electrode, and the electric potentials on the second electrode along the extension direction of the second electrode are the same, and the electric field strength is substantially zero.
  • these electromechanical coupling coefficient components k 21 2 , k 22 2 , k 23 2 , k 24 2 , k 25 2 and k 26 2 cause smaller parasitic heterogeneous modes, so that the resonator has a larger electromechanical coupling coefficient and the parasitic heterogeneous modes are effectively suppressed.
  • a first electrode, a piezoelectric layer and a plurality of second electrodes are prepared, including: forming a metal layer on one side of the piezoelectric layer; bonding a structure including the piezoelectric layer and the metal layer to a substrate so that the metal layer is stacked between the piezoelectric layer and the substrate, and the metal layer forms a first electrode.
  • a first electrode, a piezoelectric layer and a plurality of second electrodes are prepared, including: bonding the piezoelectric layer to a substrate; opening a cavity in the substrate, and the cavity passes through from the back side of the substrate to the piezoelectric layer, the back side of the substrate being the surface away from the first electrode; forming a metal layer on the bottom surface of the cavity, the metal layer forming the first electrode.
  • the method when preparing a plurality of second electrodes, includes: providing a plurality of second electrodes arranged side by side on one side of the piezoelectric layer, with a first gap between two adjacent second electrodes; and opening a first groove at a position of the piezoelectric layer opposite to the first gap.
  • the groove helps to further suppress or frequency-shift the parasitic mode and increase the electromechanical coupling coefficient of the resonator.
  • the preparation method before setting the first electrode on the side of the dielectric layer away from the substrate, the preparation method further includes: setting a conductive first conductive connecting layer on the side of the dielectric layer away from the substrate, and then setting the first electrode on the side of the first conductive connecting layer away from the dielectric layer; before setting the piezoelectric layer on the side of the first electrode away from the substrate, the preparation method further includes: setting a conductive second conductive connecting layer on the side of the first electrode away from the substrate, and then setting the piezoelectric layer on the side of the second conductive connecting layer away from the first electrode.
  • connection layer can increase the connection strength between film layers and reduce resistance.
  • the preparation method further comprises:
  • the preparation method further comprises:
  • first bus bar and a second bus bar wherein one of every two adjacent second electrodes in the plurality of second electrodes is a first interdigitated electrode and the other is a second interdigitated electrode, the first interdigitated electrode and the second interdigitated electrode are spaced apart in a first direction, and the extension direction of the first interdigitated electrode and/or the second interdigitated electrode is perpendicular to the first direction, the plurality of first interdigitated electrodes are connected by the first bus bar, and the plurality of second interdigitated electrodes are connected by the second bus bar;
  • the finger spacing P and the thickness d of the piezoelectric layer satisfy: P/d ⁇ 0.5;
  • each first interdigitated electrode is s1
  • the spacing between each two adjacent first interdigitated electrodes and second interdigitated electrodes is s2
  • the finger spacing P s1+s2
  • the width dimension is parallel to the surface of the substrate and perpendicular to the extension direction of the first interdigitated electrodes.
  • the preparation method further comprises:
  • first bus bar and a second bus bar wherein one of every two adjacent second electrodes in the plurality of second electrodes is a first interdigitated electrode and the other is a second interdigitated electrode, the first interdigitated electrode and the second interdigitated electrode are spaced apart in a first direction, and the extension direction of the first interdigitated electrode and/or the second interdigitated electrode is perpendicular to the first direction, the plurality of first interdigitated electrodes are connected by the first bus bar, and the plurality of second interdigitated electrodes are connected by the second bus bar;
  • the finger spacing P satisfies: Where: Vs is the shear wave velocity of the substrate, f is the operating frequency of the resonator;
  • each first interdigitated electrode is s1
  • the spacing between each two adjacent first interdigitated electrodes and second interdigitated electrodes is s2
  • the finger spacing P s1+s2
  • the width dimension is parallel to the surface of the substrate and perpendicular to the extension direction of the first interdigitated electrodes.
  • the present application also provides a filter, which may include a plurality of electrically connected resonators, and at least one of the plurality of resonators may be the resonator mentioned above.
  • the filter provided in the present application includes the resonator in the above-mentioned implementation structure, and the resonator not only has a large electromechanical coupling coefficient, but can also suppress or drift parasitic heterogeneous modes, this resonator is used in the filter to improve the out-of-band suppression performance of the filter.
  • the present application further provides a duplexer, which includes a transmitting channel filter and a receiving channel filter, and at least one of the transmitting channel filter and the receiving channel filter can be filtered using the above-mentioned filter.
  • the present application also provides a multiplexer, which includes multiple transmit channel filters and multiple receive channel filters, wherein at least one of the multiple transmit channel filters, or at least one of the multiple receive channel filters can adopt the filter involved in the embodiment of the present application.
  • the present application also provides an electronic device, which includes an amplifier, and the filter, duplexer or multiplexer in the above-mentioned implementable manner, and the filter, duplexer or multiplexer can be electrically connected to the amplifier.
  • the electronic device provided in the embodiment of the present application includes the above-mentioned filter, duplexer or multiplexer. Therefore, the electronic device provided in the embodiment of the present application and the filter, duplexer or multiplexer of the above-mentioned technical solution can solve the same technical problem and achieve the same expected effect.
  • FIG1 is a schematic diagram of a partial structure of an electronic device
  • FIG2 is a schematic diagram of a partial structure of an electronic device
  • FIG3 is a schematic diagram of a partial structure of a filter in an electronic device
  • FIG4 is a schematic diagram of a partial structure of a resonator
  • FIG5A is a schematic diagram of a partial structure of a resonator
  • FIG5B is a schematic diagram of a partial structure of a resonator
  • FIG6A shows an admittance curve near the main resonant mode frequency of the structure SH1 shown in FIG5A ;
  • FIG6B shows the admittance curve near the main resonant mode frequency of the structure SH1 shown in FIG5B ;
  • FIG7A is a schematic diagram showing a partial structure of a resonator provided in an embodiment of the present application.
  • FIG7B is a schematic diagram showing a partial structure of a resonator provided in an embodiment of the present application.
  • FIG8A shows an admittance curve near the main resonant mode frequency of structure A1 shown in an embodiment of the present application
  • Figure 8B shows the admittance curve near the main resonant mode frequency of SH1
  • FIG9 is a schematic diagram of a partial structure of a resonator provided in an embodiment of the present application.
  • FIG10 is a top view of a resonator provided in an embodiment of the present application.
  • FIG11A shows an admittance curve near the main resonant mode frequency of structure A1 shown in an embodiment of the present application
  • Figure 11B shows the admittance curve near the main resonant mode frequency of SH1
  • FIG12 is a schematic diagram of a partial structure of a resonator provided in an embodiment of the present application.
  • FIG13 is a schematic diagram of a partial structure of a resonator provided in an embodiment of the present application.
  • FIG15 is a schematic diagram of a partial structure of a resonator provided in an embodiment of the present application.
  • FIG16 is a schematic diagram of a partial structure of a resonator provided in an embodiment of the present application.
  • FIG17 is a top view of a resonator provided in an embodiment of the present application.
  • Fig. 18 is a cross-sectional view taken along line A-A of Fig. 17;
  • FIG19A is a schematic diagram of a partial structure of a resonator provided in an embodiment of the present application.
  • FIG19B is a schematic diagram of a partial structure of a resonator provided in an embodiment of the present application.
  • FIG20 is a graph showing an electromechanical coupling coefficient of a resonator provided in an embodiment of the present application.
  • FIG21 is a top view of a resonator provided in an embodiment of the present application.
  • Fig. 22 is a cross-sectional view taken along line B-B of Fig. 21;
  • FIG23 is a detailed view of the first interdigitated electrode in FIG21;
  • Fig. 24 is a cross-sectional view taken along line C-C of Fig. 21;
  • 25A to 25C are process structure diagrams of a resonator manufacturing method provided in an embodiment of the present application.
  • 26A to 26E are process structure diagrams of a resonator manufacturing method provided in an embodiment of the present application.
  • FIG27 is a schematic diagram of the structure of a filter provided in an embodiment of the present application.
  • FIG28 is an admittance curve and a filter passband of each resonator in FIG27;
  • FIG29 is a top view of a filter provided in an embodiment of the present application.
  • FIG30 is a partial structure of a cross-sectional view of a filter provided in an embodiment of the present application.
  • FIG31 is a partial structure of a cross-sectional view of a filter provided in an embodiment of the present application.
  • Reference numerals 100- electronic equipment; 200 - filter; 300-Resonator; 400, 410, 420, 430 - resonators; 500-antenna; 600-Receiver; 700 - Transmitter; 800-baseband chip; 900-switch; 60a, 60c, 70a - filter; 60b - low noise amplifier; 60d - mixer; 60e - buffer; 60f, 70d - voltage controlled oscillator; 70b - amplifier; 70c - driver; 10-substrate; 101-cavity; 20- a first electrode; 30- piezoelectric layer; 40-second electrode; 401-first interdigital electrode; 402-second interdigital electrode; 50-dielectric layer; 601-first bus bar; 602-second bus bar; 60a, 60b – conductive connection layer; 701 – first groove; 702 – second groove; 80 – protective layer; 90–Bragg reflection structure; 110, 120 – reflection grids; 10a – grid bars. 130, 140
  • Piezoelectric effect includes direct piezoelectric effect and inverse piezoelectric effect.
  • the direct piezoelectric effect refers to the change of the polarization of piezoelectric materials when they are subjected to mechanical force
  • the inverse piezoelectric effect refers to the deformation of the material after an external electric field is applied to the piezoelectric material.
  • the main reasons for the piezoelectric effect are the anisotropy of the crystal structure of the piezoelectric material itself and the polarization effect.
  • Main resonant mode, parasitic mixed mode The parasitic resonant frequency generated by the resonator may be close to the main resonant frequency.
  • the parasitic resonance may affect the main resonant mode, thereby affecting the in-band insertion loss performance and out-of-band suppression performance of the filter.
  • the parasitic resonance of the resonator is usually called a mixed mode, or a parasitic mixed mode. When the mixed mode falls near the main resonant mode, for example, near the resonance point and anti-resonance point of the main resonant mode, it will affect the in-band insertion loss performance and out-of-band suppression performance of the filter.
  • Piezoelectric coupling factor K t 2 It is a key parameter of the resonator.
  • the electromechanical coupling factor K t 2 can reflect the conversion efficiency between mechanical energy and electrical energy.
  • the electromechanical coupling factor K t 2 of the resonator determines the relative frequency width of the anti-resonance frequency and the resonant frequency of the resonator. For example, when the resonator is used in filter design, this relative frequency width directly determines the bandwidth of the filter. It can be considered that the larger the electromechanical coupling coefficient K t 2 , the larger the bandwidth of the filter built by the ladder structure, and the better the performance.
  • c 1323 c 3132
  • the component order can be simplified, and ⁇ 23,32 ⁇ 4, ⁇ 13,31 ⁇ 5, ⁇ 12,21 ⁇ 6 can be defined.
  • c 1323 c 3132 ⁇ c 54
  • the electromechanical coupling coefficient component k xy 2 is calculated from the elastic tensor component, piezoelectric tensor component, and dielectric tensor component of the material, and the formula is:
  • x ⁇ 1, 2, 3 ⁇
  • y ⁇ 1, 2, 3, 4, 5, 6 ⁇
  • ⁇ xx S is the dielectric tensor component under fixed strain
  • cyy E is the elastic tensor component under fixed electric field strength.
  • ⁇ S 11 43.6* ⁇ 0
  • ⁇ S 33 29.2* ⁇ 0
  • ⁇ S 22 ⁇ S 11
  • ⁇ 0 is the dielectric constant of vacuum, 8.85*10 -12 F/m.
  • the remaining components can be obtained through tensor symmetry, and the components without values are zero.
  • the components are simplified expressions, and the fourth-order elastic tensor component c E ijkl and the third-order piezoelectric tensor component e ijk can be expanded accordingly.
  • the electromechanical coupling coefficient K t 2 is determined by the electromechanical coupling coefficient component k xy 2 and the mode excited by the specific resonator structure. Generally speaking, the larger the k xy 2 corresponding to the main resonant mode of the resonator, the larger the K t 2 of the resonator. For example, when lithium niobate (LN) is selected as the piezoelectric material, the maximum electromechanical coupling coefficient component k xy 2 of LN can reach 0.9253.
  • LN lithium niobate
  • the resonator that uses this component to generate the main resonant mode has an overall larger electromechanical coupling performance, for example, the electromechanical coupling coefficient K t 2 of the resonator can reach 25%.
  • the larger the electromechanical coupling coefficient component k xy 2 corresponding to the main resonant mode the smaller the other electromechanical coupling coefficient components k xy 2 , and the resonator exhibits a larger electromechanical coupling coefficient and a smaller parasitic mode.
  • one resonant mode corresponds to one electromechanical coupling coefficient component k xy 2 .
  • the maximum electromechanical coupling coefficient component k xy 2 of LN may include k 16 2 , k 15 2 , k 34 2 , and k 35 2 .
  • the modes generated are the main resonant modes, and the modes generated by the remaining electromechanical coupling coefficient components may be heterogeneous modes.
  • the maximum electromechanical coupling coefficient component k 16 2 is excited to generate the main resonance mode zero-order horizontal shear mode (Zero-order Shear Horizontal mode) SH0 mode; in XBAR, the maximum electromechanical coupling coefficient component k 15 2 is excited to generate the main resonance mode first-order anti-symmetry mode (First-order Anti-symmetry mode) A1 mode; in YBAR, the maximum electromechanical coupling coefficient component k 34 2 is excited to generate the main resonance mode first-order horizontal shear mode (First-order Shear Horizontal mode) SH1 mode.
  • Quality Factor Q represents the energy utilization rate of the device, that is, the ratio of the total energy received by the device to the energy dissipated in one vibration cycle.
  • the electromechanical coupling coefficient Kt2 of the resonator constituting the filter and the quality factor Q value are both important parameters.
  • Euler angle of piezoelectric material The Euler angle characterizes the relative rotation angle between the original piezoelectric crystal structure in the X direction or Y direction, which is perpendicular or parallel to the extension direction of the resonator fingers in the wafer plane.
  • Admittance curve abs(Y)
  • Re(Y) is the real part of Y, that is, the conductance G, representing the loss of the resonator.
  • R-a-R Range The frequency range around the resonance frequency (Resonance Frequency) fr and the anti-resonance frequency (Anti-resonance Frequency) fa.
  • the R-a-R range is (fr-(fa-fr) to (fa+(fa-fr)).
  • Electromechanical coupling R-aR The relative bandwidth based on the resonant frequency fr and the anti-resonant frequency fa is used to express the electromechanical coupling coefficient of the resonator.
  • the R-aR of the resonator should be comparable to the relative bandwidth of the target filter.
  • R-aR (fa-fr)/((fa+fr)/2).
  • the embodiment of the present application provides an electronic device, which includes but is not limited to products such as radio frequency front ends and filter amplifier modules, and may also include mobile phones, tablet computers (pads), smart wearable products (e.g., smart watches, smart bracelets), virtual reality (VR) devices, augmented reality (AR), drones and other terminal devices, or may also be base stations, televisions, routers, cars and other devices.
  • products such as radio frequency front ends and filter amplifier modules
  • mobile phones tablet computers (pads)
  • smart wearable products e.g., smart watches, smart bracelets
  • VR virtual reality
  • AR augmented reality
  • drones and other terminal devices or may also be base stations, televisions, routers, cars and other devices.
  • the embodiment of the present application does not impose any special restrictions on the specific form of the above electronic devices.
  • the electronic device 100 may include a filter 200, which may effectively filter out a frequency point of a specific frequency in a signal or frequencies other than the frequency point to obtain a signal of a specific frequency, or eliminate a signal after a specific frequency, so as to improve the working performance of the electronic device 100.
  • a filter 200 which may effectively filter out a frequency point of a specific frequency in a signal or frequencies other than the frequency point to obtain a signal of a specific frequency, or eliminate a signal after a specific frequency, so as to improve the working performance of the electronic device 100.
  • FIG2 shows a partial circuit diagram of some electronic devices 100.
  • the electronic device 100 includes a receiver 600, a transmitter 700, an antenna 500, and a baseband chip 800.
  • the antenna 500 is electrically connected to the receiver 600 and the transmitter 700 through a switch 900, and the receiver 600 and the transmitter 700 are electrically connected to the baseband chip 800.
  • a filter 60a and a filter 60c are included, a low noise amplifier 60b is electrically connected between the filter 60a and the filter 60c, the filter 60c is electrically connected to a buffer 60e through a mixer 60d, and the buffer 60e is electrically connected to a voltage controlled oscillator 60f.
  • FIG2 is only an exemplary receiver, and electronic components can be added or reduced based on this circuit structure.
  • a power amplifier (PA) 70 b is included in the transmitter 700 shown in FIG. 2 .
  • the power amplifier 70b is electrically connected to the filter 70a and the driver 70c respectively, and the driver 70c is electrically connected to the voltage controlled oscillator 70d.
  • FIG2 is only an exemplary transmitter, and electronic devices can be added or reduced based on this circuit structure.
  • the filter can effectively filter out the frequency point of a specific frequency amplified by the power amplifier or frequencies other than the specific frequency point, or the filter can filter out the noise signals of the low noise amplifier.
  • the filter 200 may include a plurality of resonators 300 connected in series, or a plurality of resonators 300 connected in parallel, or a combination of resonators 300 connected in series and in parallel.
  • At least one of the plurality of resonators included in the filter 200 may be the resonator shown in FIG. 4 .
  • FIG. 4 shows a part of a process structure diagram of a resonator.
  • the resonator includes a substrate 10, a first electrode 20, a piezoelectric layer 30, and a plurality of second electrodes 40.
  • the plurality of second electrodes 40 are arranged side by side in a first direction, the piezoelectric layer 30 has a first side and a second side, the plurality of second electrodes 40 are located on the first side, and the first electrode 20 and the substrate 10 are located on the second side.
  • the piezoelectric layer 30 is stacked between the first electrode 20 and the plurality of second electrodes 40.
  • the plurality of second electrodes are arranged along the first direction, and the first direction can be understood as a direction perpendicular to or nearly perpendicular to the extension direction of the second electrode 40.
  • the first direction is parallel to the extension direction of the piezoelectric layer 30; or in other words, the first direction is perpendicular to the stacking direction of the piezoelectric layer and the first electrode and the second electrode.
  • the first electrode 20 may not be connected to an electrical signal, and an alternating voltage of a certain frequency is applied to the second electrode 40, so that an electric field E is generated between the first electrode 20 and the second electrode 40 along the thickness direction of the piezoelectric layer 30, and the piezoelectric layer 30 uses the electric field to form a piezoelectric effect.
  • the example in FIG4 is to use the vertical electric field E to excite the piezoelectric layer 30 to generate resonance, thereby generating conversion between electrical energy and mechanical energy.
  • the resonator shown in FIG4 is a resonator that excites resonance in the thickness direction of the piezoelectric layer 30.
  • it can be referred to as a vertically-excited bulk acoustic resonator (YBAR).
  • the thickness direction of the piezoelectric layer 30 here can be understood as a direction on the piezoelectric layer 30 that is parallel to the stacking direction of multiple membrane layers (substrate, first electrode, piezoelectric layer).
  • FIG5A and FIG5B show process structure diagrams of resonators of two different structures.
  • a cavity 101 is provided in the substrate 10, and such a resonator can be called a cavity-type suspended piezoelectric thin film resonator;
  • the substrate 10 in FIG5B is a solid structure without the cavity 101, and, compared with FIG5A, other layer structures can be stacked between the first electrode 20 and the substrate 10, for example, a dielectric layer 50 or other functional layer structures can be stacked between the substrate 10 and the first electrode 20, and such a resonator in FIG5B can be called a solid substrate piezoelectric thin film resonator.
  • the structure shown in FIG. 5A and FIG. 5B can be understood as follows: the first electrode 20 has a first surface and a second surface that are opposite (can also be called opposite or opposite), and the first surface is closer to the piezoelectric layer 30 than the second surface; in the cavity-type suspended piezoelectric thin film resonator of FIG. 5A , the substrate 10 is provided with a cavity 101, at least part of the second surface of the first electrode 20 is used to enclose the cavity 101, and at least part of the first electrode 20 is disposed between the cavity 101 and the piezoelectric layer 30; in the solid substrate piezoelectric thin film resonator of FIG.
  • the first electrode 20 is disposed between the dielectric layer 50 and the piezoelectric layer 30, and the second surface of the first electrode 20 is completely disposed on the dielectric layer 50.
  • the first electrode 20 is disposed between the substrate 10 and the piezoelectric layer 30, and the second surface of the first electrode 20 is completely disposed on the substrate 10.
  • the electromechanical coupling coefficient component k xy 2 determines the size of the electromechanical coupling coefficient K t 2. For example, in the structure shown in FIG. 5A and FIG. 5B above, if the piezoelectric layer 30 has a larger electromechanical coupling coefficient component k 34 2 , for example, the electromechanical coupling coefficient component k 34 2 reaches 0.9253, the corresponding first-order horizontal shear mode (First-order Shear Horizontal mode) SH1 mode will be excited as the main resonant mode. As shown in FIG. 5A and FIG. 5B, in the SH1 main resonant mode, the vibration direction is the direction 2 shown in FIG. 5A and FIG. 5B, that is, the vibration direction is along the extension direction of the second electrode 40.
  • the vibration direction is the direction 2 shown in FIG. 5A and FIG. 5B, that is, the vibration direction is along the extension direction of the second electrode 40.
  • FIG. 5A and FIG. 5B can provide a larger electromechanical coupling coefficient K t 2 by using the SH1 mode, but at resonance Several different types of parasitic modes appear near the frequency range of the main resonant mode resonance point and the main resonant mode anti-resonant point of the device.
  • Figure 6A shows the admittance curve near the main resonant mode frequency of the structure SH1 shown in Figure 5A
  • Figure 6B shows the admittance curve near the main resonant mode frequency of the structure SH1 shown in Figure 5B.
  • the S0 longitudinal wave mode is generated by the electromechanical coupling coefficient component k 11 2 excited by the electric field along direction 1.
  • the vibration direction is along direction 1, that is, the vibration direction is parallel to the substrate surface and perpendicular to the extension direction of the second electrode 40.
  • the parasitic modes fall near the resonance point of the main resonant mode.
  • the parasitic modes include the S0 longitudinal wave mode and the first-order anti-symmetric mode (First-order Anti-symmetry mode) A1 mode, wherein the S0 longitudinal wave mode is generated by the electromechanical coupling coefficient component k 11 2 excited by the electric field along direction 1.
  • the vibration direction is parallel to the substrate surface and perpendicular to the extension direction of the second electrode 40.
  • the A1 mode is generated by the electromechanical coupling coefficient component k 35 2 excited by the electric field along direction 3.
  • the vibration direction is parallel to the substrate surface and perpendicular to the extension direction of the second electrode 40.
  • Direction 1 involved in the embodiment of the present application can be understood as a direction parallel to the substrate surface and perpendicular to the extension direction of the second electrode 40
  • direction 2 is parallel to the extension direction of the second electrode 40
  • direction 3 is parallel to the thickness direction of the piezoelectric layer 30 .
  • E1 is an electric field parallel to the substrate surface and perpendicular to the extension direction of the second electrode 40
  • E2 is an electric field parallel to the extension direction of the second electrode 40
  • E3 is an electric field parallel to the thickness direction of the piezoelectric layer 30 .
  • resonator structures not only have a higher electromechanical coupling coefficient, but can also suppress or frequency-shift parasitic modes and optimize resonator performance.
  • the value of the electromechanical coupling coefficient component k 35 2 of the piezoelectric material of the piezoelectric layer 30 is a larger value or a maximum value among the multiple electromechanical coupling coefficient component values, for example, k 35 2 >0.4.
  • the crystal cutting angle and propagation direction of the piezoelectric material of the piezoelectric layer 30 in the embodiments of the present application are X-cut, (120° ⁇ 30°) Y propagation direction; or, it can be understood that the Euler angle of the crystal of the piezoelectric material is (90°, 90°, 120° ⁇ 30°).
  • the "X" in the above-mentioned X-cut represents the X direction of the piezoelectric material.
  • the X-cut can be used to indicate that the X direction of the piezoelectric material is in the same direction as the thickness direction of the piezoelectric layer 30 (such as the P direction in Figure 7A), and the propagation direction of the piezoelectric material is parallel to the surface of the piezoelectric layer and perpendicular to the extension direction of the second electrode 40.
  • the Y direction of the piezoelectric material 120° ⁇ 30° is in the same direction as the first direction.
  • the crystal cutting angle and propagation direction of the piezoelectric material of the piezoelectric layer 30 in the embodiment of the present application are Y-cut, (90° ⁇ 30°) X-propagation direction; or, the Euler angle of the crystal of the piezoelectric material is (0°, 90°, 90° ⁇ 30°).
  • the "Y” in the above Y-cut represents the Y direction of the piezoelectric material.
  • the Y-cut can be used to indicate that the Y direction of the piezoelectric material is in the same direction as the thickness direction of the piezoelectric layer 30 (such as the P direction in Figure 7B), and the X direction of the piezoelectric material (90° ⁇ 30°) is in the same direction as the first direction.
  • the "same direction" positioning mentioned above allows a certain error, and can be close to the same direction.
  • the difference between the two angles within 5° (including 5°) can be regarded as close to the same direction.
  • the Euler angles, cutting angles or propagation directions involved in the embodiments of the present application are limited.
  • the tangent direction of piezoelectric materials generally has an accuracy of ⁇ 0.5°, such as: X-cut ⁇ 0.5°, Y-cut ⁇ 0.5°, etc. In terms of Euler angles, it is (90° ⁇ 0.5°, 90° ⁇ 0.5°, 120° ⁇ 30°) or (0° ⁇ 0.5°, 90° ⁇ 0.5°, 90° ⁇ 30°).
  • the Euler angles may be (89.5°, 90.5°, 150°), or the Euler angles may be (89.5°, 90.5°, 90°), or the Euler angles may be (89.5°, 90.5°, 120°), or the Euler angles may be (89.5°, 90°, 110°), or the Euler angles may be (90°, 90°, 140°).
  • the Euler angles may be (0.5°, 89.5°, 90°), or the Euler angles may be (0°, 90.5°, 110°), or the Euler angles may be (0°, 90.5°, 120°), or the Euler angles may be (0.5°, 90.5°, 100°), or The Euler angles can be (0.5°, 90°, 115°).
  • the electromechanical coupling coefficient component k352 can generate the A1 main resonance mode.
  • the generated parasitic modes will also be effectively suppressed or frequency-shifted outside the operating frequency range.
  • the suppression situation can be analyzed by referring to the following Table 1.
  • the Euler angle of the crystal of the piezoelectric material is (90°, 90°, 30°)
  • the main resonant mode of the excitation is the SH1 mode
  • the values of the components of each electromechanical coupling coefficient are;
  • the Euler angle of the crystal of the piezoelectric material is (0°, 90°, 0°)
  • the main resonant mode of the excitation is the SH1 mode, and the values of the components of each electromechanical coupling coefficient are.
  • the Euler angles of the crystal of the piezoelectric material are (90°, 90°, 120°), the main resonant mode of the excitation is the A1 mode, and the values of the components of each electromechanical coupling coefficient; for the larger k 35 2 component, the Euler angles of the crystal of the piezoelectric material are (0°, 90°, 90°), the main resonant mode of the excitation is the A1 mode, and the values of the components of each electromechanical coupling coefficient.
  • the electric field that excites the relevant components is E 2. Since the electric field E 2 is parallel to the extension direction of the second electrode 40, the electric potential along the extension direction of the second electrode 40 is substantially the same, and the electric field strength is substantially zero, so these electromechanical coupling coefficient components excite smaller parasitic modes.
  • the excited electric field is the electric field E 2 , and the electric field E 2 is along the extension direction of the second electrode 40, the electric potential is substantially the same, and the electric field strength is substantially zero, so these electromechanical coupling coefficient components excite smaller parasitic modes.
  • i,j,k,m,n ⁇ 1,2,3 ⁇
  • T stress
  • S strain
  • E electric field intensity
  • c elastic tensor
  • e piezoelectric tensor
  • stress Tij is related to ekij Ek .
  • the electromechanical coupling coefficient component K 16 2 0.03
  • the electric field that excites the electromechanical coupling coefficient component K 16 2 is E 1
  • the electric field E 1 is relatively large, and then under the excitation of the electric field, the electromechanical coupling coefficient component K 16 2 will be excited to generate a parasitic mode.
  • the subscript k value corresponding to the above formula is equal to 1.
  • the electromechanical coupling coefficient component K 22 2 0.32
  • the electric field that excites the electromechanical coupling coefficient component K 22 2 is E 2
  • the electric field E 2 is substantially zero
  • the electromechanical coupling coefficient component K 22 2 is substantially not excited to generate a parasitic mode. That is, since E 2 along the extension direction of the second electrode 40 is very small, the stress generated by the piezoelectric effect excited by it will also be small, thereby reducing the vibration of the corresponding resonant mode.
  • the subscript k value corresponding to the above formula is equal to 2.
  • the embodiment of the present application is to rotate the crystal orientation of the piezoelectric material in the related art by 90° around direction 3 (i.e., along the thickness direction of the piezoelectric layer) to obtain the crystal orientation structure of the present application, obtain the maximum k 35 2 component, and obtain the A1 main resonance mode in the structure of the resonator.
  • 8A and 8B are simulations for the cavity-type suspended piezoelectric thin film resonator shown above.
  • the A1 mode resonator can use an X-cut, 120° Y propagation direction, and the Euler angles of the piezoelectric material crystal are (90°, 90°, 120°), to obtain the maximum K 35 2
  • the SH1 mode resonator can use an X-cut, 30° Y propagation direction, and the Euler angles of the piezoelectric material crystal are (90°, 90°, 30°), to obtain the maximum K 34 2 .
  • FIG. 8A is a simulation curve obtained by using the structural definition shown in Table 2
  • FIG. 8B is a simulation curve obtained by using the structural definition shown in Table 3.
  • FIG. 9 shows a process structure diagram of a resonator
  • FIG. 10 shows a distribution diagram of the second electrode in FIG. 9
  • the plurality of second electrodes include a plurality of first interdigitated electrodes 401 and a plurality of second interdigitated electrodes 402 .
  • the plurality of first interdigital electrodes 401 are connected via the first bus bar 601, and the plurality of second interdigital electrodes 402 are connected via the second bus bar 602.
  • the first bus bar 601 and the second bus bar 602 are arranged in parallel, and the first bus bar 601 and the second bus bar 602 both extend in a direction perpendicular to the extending direction of the first interdigital electrodes 401 or the second interdigital electrodes 402.
  • the first bus bar 601 and the second bus bar 602 extend in a first direction.
  • the finger pitch (Pitch) P in Table 2 and Table 3 above can be understood as shown in Figure 10, where the width of each first interdigitated electrode 401 is s1, the spacing between each adjacent two first interdigitated electrodes 401 and second interdigitated electrodes 402 is s2, and the finger pitch (Pitch) P is the sum of the width s1 and the spacing S2.
  • the width dimension s1 of the plurality of first interdigital electrodes 401 has a process tolerance
  • the interval s2 between two adjacent first interdigital electrodes 401 and second interdigital electrodes 402 also has a process tolerance
  • the piezoelectric layer thickness and the first electrode thickness in Table 2 and Table 3 above are the height dimensions of the piezoelectric layer 30 and the first electrode 20 along the stacking direction of the multiple film layer structures (such as the L direction in FIG. 9 ).
  • the duty ratios in Tables 2 and 3 are the ratios of the width s1 of the first interdigital electrode 401 to the interdigital pitch P, or the ratios of the width of the second interdigital electrode 402 to the interdigital pitch P.
  • the width of the first interdigital electrode 401 is equal to the width of the second interdigital electrode 402.
  • the modulus (abs) and real part (Re) of the admittance curve are included.
  • the vibration direction of the A1 main resonance mode is direction 1 parallel to the substrate and perpendicular to the extension direction of the second electrode 40.
  • the vibration direction of the main resonance mode SH1 is direction 2 parallel to the extension direction of the second electrode 40
  • the vibration direction of the parasitic mode generated by the excitation of the electromechanical coupling coefficient component K162 is direction 3 parallel to the thickness direction of the piezoelectric layer 30
  • the vibration direction of the parasitic mode generated by the excitation of the electromechanical coupling coefficient component K112 is direction 1 parallel to the substrate and perpendicular to the extension direction of the second electrode 40
  • the vibration direction of the parasitic mode generated by the excitation of the electromechanical coupling coefficient component K352 is direction 1 parallel to the substrate and perpendicular to the extension direction of the second electrode 40.
  • FIG. 11A and FIG. 11B are simulations for the solid substrate piezoelectric thin film resonator.
  • the A1 mode resonator can use X-cut, 120°Y propagation direction, and the Euler angles of the piezoelectric material crystal are (90°, 90°, 120°), to obtain the maximum K 35 2
  • the SH1 mode resonator can use X-cut, 30°Y propagation direction, and the Euler angles of the piezoelectric material crystal are (90°, 90°, 30°), to obtain the maximum K 34 2 .
  • FIG. 11A is a simulation curve obtained by using the structural definition shown in Table 4
  • FIG. 11B is a simulation curve obtained by using the structural definition shown in Table 5.
  • FIG. 11A shows that there is basically no large parasitic mode between the resonance point of the A1 main resonance mode and the anti-resonance point of the A1 main resonance mode, as well as near the resonance point of the A1 main resonance mode and near the anti-resonance point of the A1 main resonance mode.
  • FIG. 11A also shows that the vibration direction of the A1 main resonance mode is perpendicular to the extension of the second electrode 40. Direction of direction1.
  • the vibration direction of the main resonance mode SH1 is direction 2 parallel to the extension direction of the second electrode 40
  • the vibration direction of the parasitic mode generated by the excitation of the electromechanical coupling coefficient component K112 is direction 1 parallel to the substrate and perpendicular to the extension direction of the second electrode 40
  • the vibration direction of the parasitic mode generated by the excitation of the electromechanical coupling coefficient component K352 is direction 1 parallel to the substrate and perpendicular to the extension direction of the second electrode 40.
  • the main vibration position of the A1 main resonance mode generated by the excitation electromechanical coupling coefficient component K 35 2 is located inside the piezoelectric layer and below the second electrode 10.
  • the vibration direction is in a first-order antisymmetric form relative to the thickness direction of the piezoelectric layer, that is, it is divided into an upper and lower part along the thickness direction of the piezoelectric layer, and the upper half and the lower half vibrate in opposite directions, in an antisymmetric form.
  • the solution of obtaining a larger electromechanical coupling coefficient K 35 2 by changing the crystal orientation and exciting the A1 main resonance mode in the resonator structure and effectively suppressing the parasitic heterogeneous mode involved in the embodiments of the present application can be applied not only to cavity-type suspended piezoelectric thin film resonators, but also to solid substrate piezoelectric thin film resonator structures and the following resonator structures.
  • FIG12 is a part of a resonator process structure provided by an embodiment of the present application, wherein the resonator comprises a substrate 10, a dielectric layer 50 formed on the substrate 10, and a first electrode 20 formed on a side of the dielectric layer 50 away from the substrate 10, and a piezoelectric layer 30 formed on a side of the first electrode 20 away from the dielectric layer 50, and a plurality of second electrodes 40 formed on a side of the piezoelectric layer 30 away from the first electrode 20.
  • the substrate 10 may be a high acoustic velocity substrate, for example, any one of silicon carbide (SiC), diamond, and boron nitride (BN), or a combination of multiple materials.
  • SiC silicon carbide
  • BN boron nitride
  • the material of the piezoelectric layer 30 includes at least one of a combination of niobium and lithium, and a combination of tantalum and lithium.
  • the material of the piezoelectric layer 30 includes any one of lithium tantalate (LiTaO 3 ), lithium niobate (LiNbO 3 ), aluminum nitride (AlN), zinc oxide (ZnO), or a combination of multiple thereof.
  • the first electrode 20 can be made of any possible conductive metal (including but not limited to Al, Cu, W, Mo, Ru, Pt, etc.), or a conductive metal with high acoustic impedance (including but not limited to W, Ru, Mo, Pt, etc.). These metals with high acoustic impedance help to increase the electromechanical coupling coefficient and improve the quality factor Q, thereby further improving the performance of the resonator.
  • conductive metal including but not limited to Al, Cu, W, Mo, Ru, Pt, etc.
  • a conductive metal with high acoustic impedance including but not limited to W, Ru, Mo, Pt, etc.
  • the second electrode 40 may be made of any possible conductive metal (including but not limited to Al, Cu, W, Mo, Ru, Pt, etc.).
  • the first electrode 20 and the second electrode 40 may be made of the same conductive metal or different conductive metals.
  • a conductive connection layer 60 a may be stacked between the dielectric layer 50 and the first electrode 20 .
  • a conductive connection layer 60 b may be stacked between the piezoelectric layer 30 and the first electrode 20 .
  • the conductive connection layer 60a and the conductive connection layer 60b in FIG12 may be made of the same material or different materials, for example, any possible conductive metal (including but not limited to Ti, Cr, etc.) may be selected.
  • the bonding strength of the conductive connection layer may be selected to be 10 MPa to 40 GPa, for example, 1.5 GPa.
  • the piezoelectric layer 30 in the example of FIG12 may be lithium niobate (LiNbO 3 ), the crystal cutting angle and propagation direction may be X-cut, (120° ⁇ 30°)Y-propagation direction, and the Euler angle of the crystal of the piezoelectric material is (90°, 90°, 120° ⁇ 30°), or the crystal cutting angle and propagation direction may be Y-cut, (90° ⁇ 30°)X-propagation direction, and the Euler angle of the crystal of the piezoelectric material is (0°, 90°, 90° ⁇ 30°).
  • the electromechanical coupling coefficient k 35 2 of the resonator can be made greater than 0.4, or even equal to 0.9253.
  • the electromechanical coupling coefficient of the entire device can reach about 40%, and can be applied in scenarios with a larger passband bandwidth, for example, it can be applied in the Sub-6GHz band with a larger passband bandwidth.
  • a first groove 701 is further provided, and a first gap is provided between two adjacent second electrodes 40 .
  • the first groove 701 is provided in the piezoelectric layer 30 , and the first groove 701 is opposite to the first gap, that is, it can be understood that the first groove 701 is connected to the first gap.
  • the first groove 701 can increase the electromechanical coupling coefficient K t 2 of the resonator, and the first groove 701 can also help to suppress or Frequency shifted parasitic modes.
  • the first groove 701 does not penetrate the piezoelectric layer 30.
  • the first groove 701 penetrates the piezoelectric layer 30 and extends to the conductive connection layer 60b.
  • the structure shown in Figure 13 has opposite (or facing) bottom and top surfaces, and the bottom surface is closer to the substrate 10 than the top surface.
  • the first groove 701 extends from the top surface to the bottom surface to penetrate the piezoelectric layer 30.
  • the depth h of the first groove 701 can satisfy: 30% H ⁇ h ⁇ H, where H is the thickness of the piezoelectric layer 30 .
  • the radial dimension of the first groove 701 shown in FIG. 12 and FIG. 13 gradually decreases from the top surface to the bottom surface.
  • the inclination angle ⁇ of the first groove 701 can be: 45° ⁇ 90°.
  • the inclination angle ⁇ is about 60°
  • the inclination angle ⁇ is about 90°.
  • the inclination angle ⁇ of the first groove 701 may be understood as: the angle between the side surface of the first groove 701 and a reference plane, where the reference plane is a plane parallel to the surface of the substrate 10 .
  • FIG15 is a process structure diagram of another resonator provided in an embodiment of the present application.
  • a protective layer 80 is further included, and the side of the second electrode 40 away from the surface of the piezoelectric layer 30, the side of the second electrode 40, and the side and bottom of the first groove 701 can all be covered by the protective layer 80.
  • the protective layer 80 can protect the resonator from potential corrosion, scratches, oxidation, etc.
  • the protection layer 80 may be made of dielectric materials, for example, silicon oxide, silicon nitride, etc.
  • the protective layer 80 can also adjust the electromechanical coupling coefficient and temperature coefficient (Temperature coefficient of frequency, TCF) of the resonator to further optimize the working performance of the resonator.
  • TCF Temperature coefficient of frequency
  • Fig. 16 is a process structure diagram of another resonator provided in an embodiment of the present application.
  • a Bragg reflection structure 90 is formed on a substrate 10
  • a first electrode 20 is arranged on a side of the Bragg reflection structure 90 away from the substrate 10
  • a piezoelectric layer 30 is stacked between the first electrode 20 and the second electrode 40
  • a conductive connection layer 60a, 60b is stacked between the piezoelectric layer 30 and the first electrode 20, and between the first electrode 20 and the Bragg reflection structure 90.
  • the Bragg reflection structure includes a stacked first reflection layer and a second reflection layer, wherein the thickness t1 of the first reflection layer satisfies:
  • the thickness t2 of the second reflective layer satisfies: ⁇ 1 is the wavelength of the sound wave of the resonator at the resonant frequency in the first reflective layer material, and ⁇ 2 is the wavelength of the sound wave in the second reflective layer material.
  • the Bragg reflection structure may include three groups, or more groups, for example, ten groups.
  • the second electrode 40 formed on one side of the piezoelectric layer 30 can be arranged in the manner shown in Figure 17, and the second electrode 40 includes a plurality of first interdigitated electrodes 401 and a plurality of second interdigitated electrodes 402.
  • the plurality of first interdigitated electrodes 401 and the plurality of second interdigitated electrodes 402 can be arranged side by side, and the plurality of first interdigitated electrodes 401 and the plurality of second interdigitated electrodes 402 are arranged at intervals, that is, a second interdigitated electrode 402 can be arranged between two adjacent first interdigitated electrodes 401.
  • the plurality of first interdigital electrodes 401 are connected via a first bus bar 601
  • the plurality of second interdigital electrodes 402 are connected via a second bus bar 602 .
  • the solid high acoustic velocity substrate can be at least one of diamond, silicon carbide (SiC), and boron nitride (BN), the finger spacing P can satisfy p ⁇ Vs/2f, where Vs is the substrate 10 is the shear wave velocity, and f is the operating frequency of the resonator. This can prevent energy from leaking toward the substrate 10 and improve the Q value and electromechanical coupling coefficient of the resonator.
  • the first bus bar 601 and the second bus bar 602 are arranged in parallel, and may extend in a direction perpendicular to the extension direction of the second electrode.
  • the first bus bar 601 can be used as an input terminal, and the second bus bar 602 can be used as an output terminal.
  • an alternating voltage within a certain frequency range can be input to the plurality of first interdigital electrodes 401 through the first bus bar 601, and an alternating voltage signal processed by the resonator can be output to the plurality of second interdigital electrodes 402 through the second bus bar 602.
  • reflection grids are provided beside the plurality of first interdigital electrodes 401 and the plurality of second interdigital electrodes 402.
  • reflection grids 110 and 120 are shown, and reflection grids 110 and 120 can reflect the acoustic energy propagating outwards, and mainly concentrate the acoustic resonance energy in the area where the second electrode of the resonator is located.
  • the reflective grid includes a plurality of parallel arranged grid bars 10a, and the extending direction of the grid bars 10a is consistent with the extending direction of the second electrode 40.
  • the extending directions are consistent (or the same), which can be understood as having a certain process error, for example, the angle between them can be within 2°.
  • the reflective grating further includes a connecting bar 10b, one end of the plurality of grating bars 10a is connected via one connecting bar 10b, and the other end of the plurality of grating bars 10a is connected via another connecting bar 10b.
  • the spacing t between two grid bars 10 a satisfies the above conditions, the acoustic energy propagating outward can be better reflected back, thereby improving the quality factor Q of the resonator.
  • Fig. 18 is a cross-sectional view cut along the A-A direction of Fig. 17.
  • the side wall of the piezoelectric layer 30 can be a vertical structure, and the vertical side wall of the piezoelectric layer can reflect the sound energy propagating outward, thereby improving the quality factor Q of the resonator.
  • the side wall of the piezoelectric layer 30 in FIG. 18 can be understood as the side wall close to the ends of the plurality of second electrodes 40 , which is perpendicular to the surface of the substrate and parallel to the extension direction of the second electrodes.
  • Figures 12 to 18 show solid-state substrate piezoelectric thin film resonators
  • Figures 19A and 19B respectively show cavity-type suspended piezoelectric thin film resonators.
  • a cavity 101 is provided at a position where the substrate 10 is opposite to the first electrode 20, and the cavity 101 penetrates the substrate 10, so that at least a portion of the surface of the first electrode 20 in the working area of the resonator away from the piezoelectric layer 30 is in a suspended (or suspended) state.
  • Figure 19B the difference between Figure 19B and Figure 19A is that: in Figure 19B, the cavity 101 does not penetrate the substrate 10, and similar to the above-mentioned Figure 19A, at least a portion of the surface of the first electrode 20 in the working area of the resonator away from the piezoelectric layer 30 is in a suspended (or suspended) state.
  • a first groove 701 can also be opened in the piezoelectric layer 30, and a protective layer can also be provided covering the surface and sides of the second electrode 40, and covering the sides and bottom of the first groove 701.
  • the electromechanical coupling coefficient increases accordingly, for example, the electromechanical coupling coefficient can reach 42.75%.
  • the ratio of the finger spacing P to the thickness d of the piezoelectric layer is: 1 ⁇ P/d, or, 1 ⁇ P/d ⁇ 30, or, 1 ⁇ P/d ⁇ 20, or, 1 ⁇ P/d ⁇ 10, so that the resonator has a larger electromechanical coupling coefficient.
  • the end of the first interdigitated electrode electrically connected to the input end can be designed as a thickened structure, or can be designed as a widened structure. In this way, the transverse mode of the resonator can be suppressed, and the working performance of the resonator can be further optimized.
  • FIG. 22 is a cross-sectional view cut along the B-B direction of FIG. 21.
  • the thickness dimension D1 of the end of the first interdigital electrode 401A away from the first bus bar 601 is greater than the thickness dimension D2 of the remaining part of the first interdigital electrode 401A, and 120% ⁇ D1/D2 ⁇ 300%.
  • Figure 23 shows a detailed view of the first interdigitated electrode 401B in Figure 21.
  • the width dimension h1 of the end of the first interdigitated electrode 401B away from the first bus bar 601 is greater than the width dimension h2 of the rest of the first interdigitated electrode 401B; and 100% ⁇ h1/h2 ⁇ 200%.
  • the width dimension here is perpendicular to the extension direction of the first interdigitated electrode 401B. size of.
  • Figure 24 is a cross-sectional view cut along the C-C direction of Figure 21.
  • the piezoelectric layer 30 has a second groove 702 at a position opposite to the second gap, and the second groove 702 is connected to the second gap.
  • the present application also provides a method for preparing a resonator, the method comprising:
  • a first electrode, a piezoelectric layer and a plurality of second electrodes are prepared.
  • the plurality of second electrodes are arranged side by side in a first direction.
  • the piezoelectric layer is arranged between the first electrode and the plurality of second electrodes.
  • the first electrode is closer to the substrate than the plurality of second electrodes.
  • the crystal cutting angle and propagation direction of the piezoelectric material of the piezoelectric layer are X-cut and (120° ⁇ 30°)Y-propagation direction, and the Euler angle of the crystal of the piezoelectric material is (90°, 90°, 120° ⁇ 30°); or, the crystal cutting angle and propagation direction of the piezoelectric material are Y-cut and (90° ⁇ 30°)X-propagation direction, and the Euler angle of the crystal of the piezoelectric material is (0°, 90°, 90° ⁇ 30°); the X direction of the piezoelectric material is in the same direction as the thickness direction of the piezoelectric layer, and the Y direction of the piezoelectric material (120° ⁇ 30°) is in the same direction as the first direction; the Y direction of the piezoelectric material is in the same direction as the thickness direction of the piezoelectric layer, and the X direction of the piezoelectric material (90° ⁇ 30°) is in the same direction as the first direction.
  • the material of the first electrode may include any possible conductive metal (including but not limited to Be, Al, Cu, W, Mo, Ru, Pt, etc.).
  • a metal with high acoustic impedance including but not limited to W, Ru, Mo, Pt, etc. may be selected, which helps to increase the electromechanical coupling coefficient of the obtained resonator and improve the quality factor Q of the resonator.
  • the material of the piezoelectric layer 30 includes at least one of lithium tantalate (LiTaO 3 ), lithium niobate (LiNbO 3 ), aluminum nitride (AlN), and zinc oxide (ZnO).
  • LiTaO 3 lithium tantalate
  • LiNbO 3 lithium niobate
  • AlN aluminum nitride
  • ZnO zinc oxide
  • the following are the steps for preparing a cavity-type suspended piezoelectric thin film resonator and a solid substrate piezoelectric thin film resonator.
  • process structure diagrams corresponding to each step in preparing a solid substrate piezoelectric thin film resonator are shown.
  • a first electrode 20 and a dielectric layer 50 are sequentially formed on one side of a piezoelectric wafer.
  • the piezoelectric wafer stacked with the first electrode 20 and the dielectric layer 50 is inverted and bonded to the substrate 10.
  • the piezoelectric wafer may be thinned to a target thickness by ion implantation cutting or chemical-mechanical polishing (CMP) to form a piezoelectric layer 30.
  • CMP chemical-mechanical polishing
  • a plurality of second electrodes 40 are formed side by side on the side of the piezoelectric layer 30 away from the first electrode 20.
  • a solid substrate piezoelectric thin film resonator is obtained.
  • Figures 25A to 25C only show some steps in the method for preparing a solid-state substrate piezoelectric thin film resonator.
  • a Bragg reflection structure can also be formed on one side of the substrate 10, and when executing the step shown in Figure 25B, the Bragg reflection structure is bonded to the dielectric layer 50.
  • a groove can be opened in the piezoelectric layer 30.
  • an etching process can be used to etch a groove in the piezoelectric layer 30. The groove helps to further suppress or frequency-shift parasitic modes and increase the electromechanical coupling coefficient of the resonator.
  • a conductive connection layer can also be formed between the dielectric layer 50 and the first electrode 20, thereby improving the connection strength between the film layers of the resonator.
  • a first bus bar and a second bus bar may be prepared.
  • the first bus bar connects the plurality of first interdigitated electrodes in the plurality of second electrodes
  • the second bus bar connects the plurality of second interdigitated electrodes in the plurality of second electrodes.
  • the end portion of the second electrode may be thickened or widened.
  • process structure diagrams corresponding to each step in preparing a cavity-type suspended piezoelectric thin film resonator are shown.
  • the piezoelectric wafer is bonded to the substrate 10 .
  • a dielectric layer may be provided between the piezoelectric wafer and the substrate 10 .
  • the piezoelectric wafer can be thinned to a target thickness by ion implantation cutting or chemical-mechanical polishing (CMP) to form a piezoelectric layer 30.
  • CMP chemical-mechanical polishing
  • a plurality of second electrodes 40 arranged side by side are formed on a side of the piezoelectric layer 30 away from the first electrode 20 .
  • a cavity 101 is opened in the substrate 10, and the cavity 101 is made to pass through the piezoelectric layer 30. In this step, the cavity 101 needs to be opened below the resonance region where the plurality of second electrodes 40 are located.
  • a first electrode 20 is formed on the bottom surface of the cavity 101 close to the piezoelectric layer 30.
  • a cavity-type suspended piezoelectric thin film resonator is manufactured.
  • Figures 26A to 26E only show some steps in the preparation method of the cavity-type suspended piezoelectric thin film resonator. Some process steps can also be added. For example, an etching process can be used to etch a groove in the piezoelectric layer 30. The groove helps to further suppress or frequency-shift parasitic modes and increase the electromechanical coupling coefficient of the resonator.
  • a first bus bar and a second bus bar can be obtained. The first bus bar connects multiple first finger electrodes in the multiple second electrodes, and the second bus bar connects multiple second finger electrodes in the multiple second electrodes. The end of the second electrode can also be thickened or widened.
  • the cavity-type suspended piezoelectric thin film resonator or the solid-state substrate piezoelectric thin film resonator mentioned above can be used as a sensor, for example, a temperature, humidity sensor, a pressure sensor, etc. Alternatively, it can also be used as a delay line device and applied to various high-frequency signal processing such as 100MHz-30GHz.
  • the above-mentioned cavity-type suspended piezoelectric thin film resonator or solid substrate piezoelectric thin film resonator can be electrically connected in a trapezoidal structure as shown in FIG27 to realize a filter for radio frequency communication.
  • the filter there can be resonators connected in series or in parallel, and the resonant frequency of the parallel resonator can be lower than the resonant frequency of the series resonator.
  • the thicker piezoelectric layer 30 or the thicker protective layer 80 or the larger finger spacing P in the above-mentioned resonator process structure can reduce the resonant frequency of the resonator.
  • resonators 301, 302, 303, 304 and 305 are included.
  • Resonators 301, 302 and 303 are series resonators, and resonators 304 and 305 are parallel resonators.
  • At least one resonator among resonators 301 to 305 may be the resonator involved in the above-mentioned embodiment.
  • FIG28 shows the relationship between the admittance curve of each resonator of the ladder filter and the transmission loss curve of the filter in FIG27 .
  • the resonance point of the series resonator such as resonator 301, resonator 302 and resonator 303
  • the anti-resonance point of the parallel resonator such as resonator 304 and resonator 305
  • the anti-resonance point of the series resonator such as resonator 301, resonator 302 and resonator 303
  • the resonance point of the parallel resonator (such as resonator 304 and resonator 305) is located on the low frequency side outside the passband, so that the filter has the characteristics of high roll-off and high out-of-band suppression.
  • multiple resonators provided in the embodiment of the present application can be integrated on the same substrate 10.
  • a resonator 410, a resonator 420, and a resonator 430 connected in series are integrated on the substrate 10, and the resonator 410 and the resonator 420 are electrically connected through a conductive connection layer 130, and the resonator 420 and the resonator 430 are electrically connected through a conductive connection layer 140.
  • the electrically conductive connecting layer 130 or the electrically conductive connecting layer 140 may have a variety of possible structures.
  • FIG30 shows how to connect the acoustic wave resonator 410 to the conductive connection layer 130
  • FIG30 shows the arrangement of the conductive connection layer 130 in the solid substrate piezoelectric thin film resonator.
  • a dielectric layer 150 is formed on the side of the second bus bar 602 away from the substrate 10.
  • the dielectric layer 150 is not only formed on the side of the second bus bar 602, but also covers the area between the two acoustic wave resonators.
  • a hole 151 is etched in the dielectric layer 150 to penetrate to the second bus bar 602, and then a conductive material is formed on the side of the dielectric layer 150 away from the second bus bar 602 and in the hole 151 of the dielectric layer 150 to form a conductive connection portion 130 electrically connected to the second bus bar 602. In this way, the two acoustic wave resonators are electrically connected through the conductive connection layer 130.
  • FIG31 also embodies how to connect the acoustic wave resonator 410 to the conductive connection layer 130, and FIG31 also shows the arrangement of the conductive connection layer 130 in the solid substrate piezoelectric thin film resonator.
  • the difference between the structures shown in FIG31 and FIG30 is that: in FIG30, the conductive connection part 130 is arranged farther from the second bus bar 602 than the dielectric layer 150, while in FIG31, the conductive connection part 130 is closer to the second bus bar 602 than the dielectric layer 150, that is, in FIG31, the conductive connection part 130 is stacked between the dielectric layer 150 and the second bus bar 602, and is in direct contact with the second bus bar 602 to achieve electrical connection.
  • a gap 201 is formed at a position of the first electrode 20 close to the conductive connection portion 130 , thereby achieving electrical isolation between the first electrode 20 and the conductive connection portion 130 .
  • the material of the above-mentioned conductive connection layer can be any conductive metal (including but not limited to Al, Cu, etc.).
  • a dielectric layer 150 (including but not limited to) is added between the second bus bar 602 and the conductive connection layer (Pad layer) 130. Limited to SiO2, SiN, polyimide, photoresist, etc.) to avoid corresponding parasitic effects.
  • the filter involved in the above-mentioned embodiment of the present application can also be applied in a duplexer or a multiplexer.
  • a transmitting channel filter and a receiving channel filter are included, and at least one of the transmitting channel filter and the receiving channel filter can be filtered by the above-mentioned filter.
  • the multiplexer multiple transmitting channel filters and multiple receiving channel filters are included, wherein at least one of the multiple transmitting channel filters or at least one of the multiple receiving channel filters can adopt the filter involved in the embodiment of the present application.

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Abstract

本申请提供一种谐振器、滤波器，以及电子设备。涉及谐振器技术领域。该谐振器包括衬底、第一电极、压电层和多个第二电极，多个第二电极并排布设，压电层包括压电材料，并设置在第一电极和多个第二电极之间。该谐振器可以利用竖直电场激发压电层产生谐振。

Description

谐振器、滤波器、电子设备
本申请要求于2023年01月20日提交国家知识产权局、申请号为202310202885.2、发明名称为“一种谐振器、滤波器、及其制作方法”的中国专利申请的优先权，以及，本申请要求于2023年04月28日提交国家知识产权局、申请号为202310490983.0、发明名称为“声波谐振器、滤波器、电子设备”的中国专利申请的优先权，以及，本申请要求于2023年05月31日提交国家知识产权局、申请号为202310639000.5、发明名称为“谐振器、滤波器、电子设备”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及谐振器技术领域，涉及一种谐振器、具有谐振器的滤波器，以及包含滤波器或谐振器的电子设备。
背景技术
随着通讯技术的发展，电子设备所需要的谐振器的用量将显著上升。例如，水平电场激励的体声波谐振器(Horizontally-excited Bulk Acoustic Resonator，XBAR)、竖直电场激励的体声波谐振器(Vertically-excited Bulk Acoustic Resonator，YBAR)，以及，薄膜腔声谐振器(Film Bulk Acoustic Resonator，FBAR)等体声波谐振器被广泛关注。
其中，YBAR具有更大的机电耦合系数和更高效的谐振模态，可以被应用在更大的通带带宽中，比如，可以满足Sub-6GHz频段的通带带宽。
但是，目前YBAR中，在YBAR的谐振频率和反谐振频率范围附近出现了许多种不同类型的杂模，这些杂模在很大程度上干扰了主谐振模式，给谐振器和滤波器的性能带来很多问题，例如，这些杂模会使滤波器通带波纹增加，带外抑制性能变差。
发明内容
本申请提供一种谐振器、具有谐振器的滤波器，以及包含滤波器的电子设备。主要目的提供一种不仅具有较大机电耦合系数，还可以有效抑制寄生杂模的谐振器。
为达到上述目的，本申请的实施例采用如下技术方案：
一方面，本申请提供了一种谐振器。在一个实施例中，该谐振器可以是声波谐振器，例如是YBAR。
该谐振器包括衬底、第一电极、压电层和多个第二电极，多个第二电极在第一方向上并排布设，压电层具有第一侧和第二侧，多个第二电极位于第一侧，第一电极和衬底位于第二侧；即就是压电层堆叠在第一电极和第二电极之间，这样是利用第一电极和第二电极之间形成的竖直电场激发压电层产生谐振，例如，形成YBAR；另外，本申请的谐振器中，压电层包括压电材料，压电材料的晶体切割角和传播方向是X切、(120°±30°)Y传播方向，或者，压电材料的晶体的欧拉角为(90°，90°，120°±30°)，其中，压电材料X方向与压电层的厚度方向为同向，压电材料(120°±30°)Y方向与第一方向为同向；或者，压电材料的晶体切割角和传播方向是Y切、(90°±30°)X传播方向，或者，压电材料的晶体的欧拉角为(0°，90°，90°±30°)，其中，压电材料Y方向与压电层的厚度方向为同向，压电材料(90°±30°)X方向与第一方向为同向。
本申请涉及的谐振器中，压电材料的晶体切割角和传播方向可以是X切、(120°±30°)Y传播方向，即欧拉角可以为(90°，90°，120°±30°)，或者，晶体切割角和传播方向可以Y切、(90°±30°)X传播方向，即欧拉角可以为(0°，90°，90°±30°)。在此种欧拉角限定下，再结合本申请的谐振器结构，可以使得该谐振器拥有较大的机电耦合系数，比如机电耦合系数可以大于40％。
以及，在该谐振器结构中，机电耦合系数分量k35 2＞0.4，可以激励出一阶反对称A1主谐振模态，机电耦合系数分量k35 2之外的，且数值较大的k21 2、k22 2、k23 2、k24 2、k25 2和k26 2等机电耦合系数分量，激发这些机电耦合系数分量的电场方向为平行于第二电极的延伸方向，而在第二电极上沿第二电极延伸方向电势相同，电场强度为零，因此这些机电耦合系数分量k22 2、k26 2、k24 2、k32 2引起较小的寄生杂模，从而，优化整个谐振器的使用性能。
在一种可以实现的方式中，相邻两个第二电极之间具有第一间隔；压电层与第一间隔相对的位置处具有第一沟槽，第一沟槽与第一间隔贯通。
由于在压电层内形成有沟槽，沟槽有助于进一步的抑制或者频移寄生杂模，并增加该谐振器的机电耦合系数。
在一种可以实现的方式中，压电层具有位于第二侧的底面和位于第一侧的顶面，第一沟槽贯通底面和顶面。
由于沟槽自压电层的顶面贯通至底面，进而，可以进一步的增加机电耦合系数。
在一种可以实现的方式中，自顶面至底面，第一沟槽的径向尺寸逐渐增加。
比如，第一沟槽的侧面的倾斜角度α满足：45°＜α＜90°；或者，60°＜α＜90°。
在一种可以实现的方式中，波谐振器还包括保护层，第二电极的远离压电层的表面、第一间隔的侧面、第一沟槽的侧面和底面均被保护层覆盖。
该保护层可以保护谐振器免受腐蚀、划伤、氧化等影响，保护该器件的性能。另外，保护层也可以调整谐振器的谐振频率，还可以调整谐振器的机电耦合系数和温度系数(Temperature coefficient of frequency，TCF)。
在一种可以实现的方式中，第一电极具有相对的第一面和第二面，第一面相比第二面更加靠近压电层；衬底设有空腔，第一电极的第二面的至少部分用于围设空腔，且第一电极的至少部分设置于空腔与压电层之间。
在一种可以实现的方式中，谐振器的机电耦合系数Kt 2≥20％。
这样形成的谐振器可以被称为空腔型悬浮谐振器，在该种结构的谐振器中，由于机电耦合系数分量k35 2＞0.4，使得该谐振器的机电耦合系数可以达到20％以上。
在一种可以实现的方式中，谐振器还包括：第一汇流条和第二汇流条；多个第二电极中每相邻两个第二电极中一个为第一叉指电极，另一个为第二叉指电极，第一叉指电极和第二叉指电极在第一方向上间隔，且第一叉指电极和/或第二叉指电极的延伸方向垂直于第一方向；多个第二电极中的多个第一叉指电极通过第一汇流条连接，多个第二电极中的多个第二叉指电极通过第二汇流条连接；指条间距P与压电层的厚度d满足：P/d≥0.5；每个第一叉指电极的宽度尺寸为s1，每相邻两个第一叉指电极和第二叉指电极之间的间距为s2，指条间距P＝s1+s2，宽度尺寸为平行于衬底的表面且垂直于第一叉指电极延伸方向的尺寸。
在空腔型悬浮谐振器中，当指条间距P与压电层的厚度d满足：P/d≥0.5时，可以进一步的增加该谐振器的机电耦合系数。
在一种可以实现的方式中，第一电极具有相对的第一面和第二面，第一面相比第二面更加靠近压电层；第一电极设置于衬底与压电层之间，且第一电极的第二面完全设置在衬底上。
在一种可以实现的方式中，谐振器的机电耦合系数Kt 2≥10％。
这样形成的谐振器可以被称为固态衬底谐振器，在该种结构的谐振器中，由于机电耦合系数分量k35 2＞0.4，使得该谐振器的机电耦合系数可以达到10％以上。
在一种可以实现的方式中，在固态衬底谐振器中，还包括：谐振器还包括：第一汇流条和第二汇流条；多个第二电极中每相邻两个第二电极中一个为第一叉指电极，另一个为第二叉指电极，第一叉指电极和第二叉指电极在第一方向上间隔，且第一叉指电极和/或第二叉指电极的延伸方向垂直于第一方向；多个第二电极中的多个第一叉指电极通过第一汇流条连接，多个第二电极中的多个第二叉指电极通过第二汇流条连接；指条间距P满足：其中：Vs是衬底的剪切体波声速，f是谐振器的工作频率；每个第一叉指电极的宽度尺寸为s1，每相邻两个第一叉指电极和第二叉指电极之间的间距为s2，指条间距P＝s1+s2，宽度尺寸为平行于衬底的表面且垂直于第一叉指电极延伸方向的尺寸。
当指条间距P满足：时，可以防止能量从压电层向衬底层泄露，以提升品质因数Q值和机电耦合系数。
在一种可以实现的方式中，衬底包括碳化硅、氮化硼、金刚石中的至少一种。
在一种可以实现的方式中，衬底的厚度尺寸Z满足：Z≥4d，d为压电层的厚度尺寸，衬底的厚度尺寸和压电层的厚度尺寸均为垂直于衬底表面的方向上的尺寸。
这样，可以进一步提升品质因数Q值和机电耦合系数。
在一种可以实现的方式中，在固态衬底谐振器中，还包括堆叠的第一反射层和第二反射层；第一反射层和第二反射层设置在衬底和第一电极之间；其中，第一反射层的厚度t1满足： 第二反射层的厚度t2满足：其中，λ1为谐振器在谐振频率下的声波在第一反射层材料中的波长，λ2为该声波在第二反射层材料中的波长。
可以将堆叠的第一反射层和第二反射层视为一组，在一些示例中，可以设置三组至十组。
在一种可以实现的方式中，衬底和第一电极之间堆叠有介电层，介电层的厚度g满足：g＝λ/4，其中，λ为谐振器在谐振频率下的声波在介电层的材料的波长。
通过在衬底和第一电极之间设置介电层，防止压电层和衬底之间耦合，进而，可以增加该器件的机电耦合系数，并且，当介电层的厚度g满足：g＝λ/4，时，还可以进一步的提升机电耦合系数。
在一种可以实现的方式中，谐振器还包括：第一汇流条和第二汇流条；多个第二电极中每相邻两个第二电极中一个为第一叉指电极，另一个为第二叉指电极，第一叉指电极和第二叉指电极在第一方向上间隔，且第一叉指电极和/或第二叉指电极的延伸方向垂直于第一方向；多个第二电极中的多个第一叉指电极通过第一汇流条连接，多个第二电极中的多个第二叉指电极通过第二汇流条连接；指条间距P与压电层的厚度d满足：P/d≥1；每个第一叉指电极的宽度尺寸为s1，每相邻两个第一叉指电极和第二叉指电极之间的间距为s2，指条间距P＝s1+s2，宽度尺寸为平行于衬底的表面且垂直于第一叉指电极延伸方向的尺寸。
当指条间距P与压电层的厚度d满足：P/d≥1时，可以进一步的增加该谐振器的机电耦合系数，比如，可以使得该谐振器的机电耦合系数达到45％。
在一种可以实现的方式中，30≥P/d≥1，或者，20≥P/d≥1，又或者，10≥P/d≥1。
在一种可以实现的方式中，谐振器还包括导电连接层；导电连接层堆叠在第一电极和压电层之间。
这样，可以增加第一电极和压电层之间的连接强度。避免因为第一电极晶格和压电层晶格不匹配，导致层与层之间黏附性较差，影响器件牢固性。
在一种可以实现的方式中，多个第二电极的至少部分第二电极包括第一端部和第二端部，第一端部的厚度尺寸D1，大于第二端部的厚度尺寸D2；且120％≤D1/D2≤300％。
当120％≤D1/D2≤300％时，可以抑制横模。
在一种可以实现的方式中，多个第二电极的至少部分第二电极包括第一端部和第二端部，第一端部的宽度尺寸h1，大于第二端部的宽度尺寸h2；且100％＜h1/h2≤200％；宽度尺寸为垂直于第二电极延伸方向的尺寸。
当100％＜h1/h2≤200％时，同样的，可以抑制横模。
在一种可以实现的方式中，谐振器还包括：第一汇流条和第二汇流条；多个第二电极中每相邻两个第二电极中一个为第一叉指电极，另一个为第二叉指电极，第一叉指电极和第二叉指电极在第一方向上间隔，且第一叉指电极和/或第二叉指电极的延伸方向垂直于第一方向；多个第二电极中的多个第一叉指电极通过第一汇流条连接，多个第二电极中的多个第二叉指电极通过第二汇流条连接；第一叉指电极的与第一汇流条连接的端部为指条连接端，另一端为指条尖端，指条尖端与第二汇流条之间具有第二间隔；压电层的与第二间隔相对的位置处具有第二沟槽，第二沟槽与第二间隔贯通。
在一种可以实现的方式中，谐振器还包括多个平行布设的栅条，多个栅条的一端通过第一连接条连接，多个栅条的另一端通过第二连接条连接，栅条的延伸方向与第二电极的延伸方向相同； 多个第二电极中每相邻两个第二电极中一个为第一叉指电极，另一个为第二叉指电极，第一叉指电极和第二叉指电极在第一方向上间隔，且第一叉指电极和/或第二叉指电极的延伸方向垂直于第一方向；多个第二电极中的多个第一叉指电极通过第一汇流条连接，多个第二电极中的多个第二叉指电极通过第二汇流条连接；相邻两个栅条之间的间距t满足：0.3≤t/P≤0.7；P为指条间距，每个第一叉指电极的宽度尺寸为s1，每相邻两个第一叉指电极和第二叉指电极之间的间距为s2，指条间距P＝s1+s2，宽度尺寸为平行于衬底的表面且垂直于第一叉指电极延伸方向的尺寸。
当0.3≤t/p≤0.7时，反射栅可以将向外传播的声能反射回来，将谐振器的能量集中在谐振器的具有第二电极的区域，提升该器件的品质因数Q。
在一种可以实现的方式中，压电层包括相对的第一侧壁和第二侧壁；第一侧壁和/或第二侧壁为垂直于衬底表面、且平行于第二电极延伸方向的平面。
第一侧壁和第二侧壁可以将向外传播的声能反射回来，将谐振器的能量集中在谐振器的具有第二电极的区域，提升该器件的品质因数Q。
在一种可以实现的方式中，压电层的材料包括铌和锂的组合、钽和锂的组合中的至少一种组合；第一电极的材料包括钨、铂、钼、铝中的至少一种。
比如，压电层的材料包括铌酸锂、钽酸锂中的至少一种。
在一种可以实现的方式中，机电耦合系数分量k35 2数值为多个机电耦合系数分量数值中的最大值。
比如，机电耦合系数分量k35 2可以达到0.9253。
在一种可以实现的方式中，0.4＜k35 2，或者，0.4＜k35 2＜0.95，又或者，0.4＜k35 2＜0.9253。
在一种可以实现的方式中，基于给多个第二电极施加电压，谐振器用于在激励压电材料的机电耦合系数分量k35 2时产生一阶反对称模态，一阶反对称模态的振动方向平行于衬底的表面且垂直于第二电极的延伸方向。
该一阶反对称A1模态为该谐振器的主谐振模态。
在一种可以实现的方式中，谐振器用于在激励机电耦合系数分量k35 2之外的至少部分机电耦合系数分量的电场平行于第二电极的延伸方向；至少部分机电耦合系数分量包括：机电耦合系数分量k21 2、k22 2、k23 2、k24 2、k25 2和k26 2中的至少一种。
即就是，由于激励机电耦合系数分量k21 2、k22 2、k23 2、k24 2、k25 2和k26 2的电场沿着第二电极的延伸方向，在该方向上，电场强度基本为零，进而使得这些机电耦合系数分量产生较小的寄生模态。
另一方面，本申请还提供了一种谐振器。
该谐振器包括第一电极、压电层和多个第二电极，多个第二电极并排布设，压电层具有第一侧和第二侧，多个第二电极位于第一侧，第一电极和衬底位于第二侧；即就是第一电极和第二电极位于压电层相对的两侧，这样是利用竖直电场激发压电层产生谐振，例如，形成YBAR；另外，本申请的谐振器中，压电层包括压电材料，压电材料的机电耦合系数分量k35 2的数值满足：k35 2＞0.4。
本申请给出的谐振器中，压电材料的机电耦合系数分量k35 2的数值满足：k35 2＞0.4，如压电材料的欧拉角为(90°，90°，120°±30°)，或者，欧拉角为(0°，90°，90°±30°)，在诸如此类晶向的限定下，可以使得该谐振器的机电耦合系数分量k35 2达到较大值，使得该谐振器拥有较大的机电耦合系数，比如机电耦合系数可以大于40％。
还有，机电耦合系数分量k35 2之外的，且数值较大的k21 2、k22 2、k23 2、k24 2、k25 2和k26 2等机电耦合系数分量，激发这些机电耦合系数分量的电场方向为平行于第二电极的延伸方向，而在第二电极上沿第二电极延伸方向电势相同，电场强度为零，因此这些机电耦合系数分量k21 2、k22 2、k23 2、k24 2、k25 2和k26 2引起较小的寄生杂模，使得该谐振器在具有较大机电耦合系数的基础上，寄生杂模还被有效抑制。
在一种可以实现的方式中，压电材料具有多个机电耦合系数分量，机电耦合系数分量k35 2的数值为多个机电耦合系数分量数值中的最大值。
在一种可以实现的方式中，0.4＜k35 2，或者，0.4＜k35 2＜0.95，又或者，0.4＜k35 2＜0.9253。
在一种可以实现的方式中，基于给多个第二电极施加电压，谐振器用于在激励压电材料的机电耦合系数分量k35 2时产生一阶反对称模态，一阶反对称模态的振动方向平行于衬底的表面且垂直于第二电极的延伸方向。
该一阶反对称A1模态为该谐振器的主谐振模态。
在一种可以实现的方式中，谐振器用于在激励机电耦合系数分量k35 2之外的至少部分机电耦合系数分量的电场平行于第二电极的延伸方向；至少部分机电耦合系数分量包括：机电耦合系数分量k21 2、k22 2、k23 2、k24 2、k25 2和k26 2中的至少一种。
即就是，由于激励机电耦合系数分量k21 2、k22 2、k23 2、k24 2、k25 2和k26 2的电场沿着第二电极的延伸方向，在该方向上，电场强度基本为零，进而使得这些机电耦合系数分量产生较小的寄生模态。
再一方面，本申请还提供一种谐振器的制备方法，该制备方法包括：
制得第一电极、压电层和多个第二电极，压电层具有第一侧和第二侧，多个第二电极位于第一侧，第一电极和衬底位于第二侧，且多个第二电极在第一方向上并排布设；
其中，压电层的压电材料的晶体切割角和传播方向是X切、(120°±30°)Y传播方向，或者，压电材料的晶体的欧拉角为(90°，90°，120°±30°)，该压电材料X方向与压电层的厚度方向为同向，压电材料(120°±30°)Y方向与第一方向为同向，或者；
压电材料的晶体切割角和传播方向是Y切、(90°±30°)X传播方向，或者压电材料的晶体欧拉角为(0°，90°，90°±30°)，该压电材料Y方向与压电层的厚度方向为同向，压电材料(90°±30°)X方向与第一方向为同向。
利用本申请给出的制备方法制得的谐振器，压电材料的晶体在此种欧拉角限定下，可以使得该谐振器拥有较大的机电耦合系数，比如机电耦合系数可以大于40％。并且，晶体在该欧拉角时，机电耦合系数分量k35 2之外的，且数值较大的k21 2、k22 2、k23 2、k24 2、k25 2和k26 2等机电耦合系数分量，激发这些机电耦合系数分量的电场方向为平行于第二电极的延伸方向，而在第二电极上沿第二电极延伸方向电势相同，电场强度基本为零，因此这些机电耦合系数分量k21 2、k22 2、k23 2、k24 2、k25 2和k26 2引起较小的寄生杂模，使得该谐振器在具有较大机电耦合系数的基础上，寄生杂模还被有效抑制。
在一种可以实现的方式中，制得第一电极、压电层和多个第二电极，包括：在压电层的一侧形成金属层；将包含有压电层和金属层的结构与衬底键合，使得金属层堆叠在压电层和衬底之间，金属层形成第一电极。
这样，就可以制得固态衬底谐振器。
在一种可以实现的方式中，制得第一电极、压电层和多个第二电极，包括：将压电层与衬底键合；在衬底内开设空腔，且空腔自衬底背面贯通至压电层，衬底的背面为远离第一电极的面；在空腔的底面形成金属层，金属层形成第一电极。
这样，就可以制得空腔型悬浮谐振器。
在一种可以实现的方式中，制得多个第二电极时，包括：在压电层的一侧设置多个并排布设的第二电极，相邻两个第二电极之间具有第一间隔；在压电层的与第一间隔相对的位置处开设第一沟槽。
当压电层内开设沟槽，该沟槽有助于进一步的抑制或者频移寄生杂模，并增加该谐振器的机电耦合系数。
在一种可以实现的方式中，在衬底的一侧设置第一电极之前，制备方法还包括：在衬底的一侧设置介电层，再在介电层的远离衬底的一侧设置第一电极，介电层的厚度g满足：g＝λ/4，其中，λ为谐振器在谐振频率下的声波在介电层的材料的波长。
这样可以进一步的提升机电耦合系数，优化制得的谐振器的性能。
在一种可以实现的方式中，在介电层的远离衬底的一侧设置第一电极之前，制备方法还包括：在介电层的远离衬底一侧设置导电的第一导电连接层，再在第一导电连接层的远离介电层的一侧设置第一电极；在第一电极的远离衬底一侧设置压电层之前，制备方法还包括：在第一电极的远离衬底一侧设置导电的第二导电连接层，再在第二导电连接层的远离第一电极一侧设置压电层。
利用导电连接层可以增加膜层之间的连接强度，降低电阻。
在一种可以实现的方式中，制备方法还包括：
在衬底内形成空腔；
在压电层的远离第一电极一侧设置多个第二电极时，制备方法还包括：
制备第一汇流条和第二汇流条，多个第二电极中每相邻两个第二电极中一个为第一叉指电极，另一个为第二叉指电极，第一叉指电极和第二叉指电极在第一方向上间隔，且第一叉指电极和/或第二叉指电极的延伸方向垂直于第一方向，多个第一叉指电极通过第一汇流条连接，多个第二叉指电极通过第二汇流条连接；
其中，指条间距P与压电层的厚度d满足：P/d≥0.5；
每个第一叉指电极的宽度尺寸为s1，每相邻两个第一叉指电极和第二叉指电极之间的间距为s2，指条间距P＝s1+s2，宽度尺寸为平行于衬底的表面且垂直于第一叉指电极延伸方向的尺寸。
在一种可以实现的方式中，在压电层的远离第一电极一侧设置多个第二电极时，制备方法还包括：
制备第一汇流条和第二汇流条，多个第二电极中每相邻两个第二电极中一个为第一叉指电极，另一个为第二叉指电极，第一叉指电极和第二叉指电极在第一方向上间隔，且第一叉指电极和/或第二叉指电极的延伸方向垂直于第一方向，多个第一叉指电极通过第一汇流条连接，多个第二叉指电极通过第二汇流条连接；
其中，指条间距P满足：其中：Vs是衬底的剪切体波声速，f是谐振器的工作频率；
每个第一叉指电极的宽度尺寸为s1，每相邻两个第一叉指电极和第二叉指电极之间的间距为s2，指条间距P＝s1+s2，宽度尺寸为平行于衬底的表面且垂直于第一叉指电极延伸方向的尺寸。
又一方面，本申请还提供一种滤波器，该滤波器可以包括多个电连接的谐振器，多个谐振器中的至少一个谐振器可以为上述涉及的谐振器。
由于本申请给出的滤波器中包括了上述实现结构中的谐振器，并且，该谐振器不仅具有较大的机电耦合系数，还可以抑制或者漂移寄生杂模，此种谐振器被应用在滤波器中，可以提升滤波器的带外抑制性能。
又一方面，本申请还提供一种双工器，该双工器包括发射通道滤波器和接收通道滤波器，该发射通道滤波器和接收通道滤波器中的至少一个可以采用上述的滤波器进行滤波。
又一方面，本申请还提供一种多工器，该多工器包括多个发射通道滤波器和多个接收通道滤波器，其中，多个发射通道滤波器中的至少一个，或者多个接收通道滤波器中的至少一个可以采用本申请实施例涉及的滤波器。
又一方面，本申请还提供一种电子设备，该电子设备包括放大器，和上述可实现方式中的滤波器、双工器或者多工器，该滤波器、双工器或者多工器可以与放大器电连接。
本申请实施例提供的电子设备包括上述滤波器、双工器或者多工器，因此本申请实施例提供的电子设备与上述技术方案的滤波器、双工器或者多工器能够解决相同的技术问题，并达到相同的预期效果。
附图说明
图1为电子设备中的部分结构示意图；
图2为电子设备中的部分结构示意图；
图3为电子设备中的滤波器的部分结构示意图；
图4为一种谐振器的部分结构示意图；
图5A为一种谐振器的部分结构示意图；
图5B为一种谐振器的部分结构示意图；
图6A展示的是图5A所示结构SH1主谐振模态频率附近的导纳曲线；
图6B展示的是图5B所示结构SH1主谐振模态频率附近的导纳曲线；
图7A展示的是本申请实施例提供的一种谐振器的部分结构示意图；
图7B展示的是本申请实施例提供的一种谐振器的部分结构示意图；
图8A展示的是本申请实施例所示结构A1主谐振模态频率附近的导纳曲线；
图8B展示的是SH1主谐振模态频率附近的导纳曲线；
图9为本申请实施例提供的一种谐振器的部分结构示意图；
图10为本申请实施例提供的一种谐振器的俯视图；
图11A展示的是本申请实施例所示结构A1主谐振模态频率附近的导纳曲线；
图11B展示的是SH1主谐振模态频率附近的导纳曲线；
图12为本申请实施例提供的一种谐振器的部分结构示意图；
图13为本申请实施例提供的一种谐振器的部分结构示意图；
图14为本申请实施例提供的一种谐振器的部分结构示意图；
图15为本申请实施例提供的一种谐振器的部分结构示意图；
图16为本申请实施例提供的一种谐振器的部分结构示意图；
图17为本申请实施例提供的一种谐振器的俯视图；
图18为沿着图17的A-A剖切的剖视图；
图19A为本申请实施例提供的一种谐振器的部分结构示意图；
图19B为本申请实施例提供的一种谐振器的部分结构示意图；
图20为本申请实施例提供的一种谐振器的机电耦合系数曲线图；
图21为本申请实施例提供的一种谐振器的俯视图；
图22为沿着图21的B-B剖切的剖视图；
图23为图21中的第一叉指电极的细节图；
图24为沿着图21的C-C剖切的剖视图；
图25A至图25C为本申请实施例提供的一种谐振器制备方法的工艺结构图；
图26A至图26E为本申请实施例提供的一种谐振器制备方法的工艺结构图；
图27为本申请实施例提供的一种滤波器的结构示意图；
图28为图27中的各个谐振器的导纳曲线与滤波器带通；
图29为本申请实施例提供的一种滤波器的俯视图；
图30为本申请实施例提供的一种滤波器剖视图的部分结构；
图31为本申请实施例提供的一种滤波器剖视图的部分结构。
附图标记：
100-电子设备；
200-滤波器；
300-谐振器；
400、410、420、430-谐振器；
500-天线；
600-接收机；
700-发射机；
800-基带芯片；
900-开关；
60a、60c、70a-滤波器；60b-低噪声放大器；60d-混频器；60e-缓冲器；60f、70d-压控振荡器；
70b-放大器；70c-驱动器；
10-衬底；101-空腔；
20-第一电极；
30-压电层；
40-第二电极；401-第一叉指电极；402-第二叉指电极；
50-介电层；
601-第一汇流条；602-第二汇流条；
60a、60b–导电连接层；
701–第一沟槽；702–第二沟槽；
80–保护层；
90–布拉格反射结构；
110、120–反射栅；10a–栅条。
130、140–连接导电层；
150–介电层。
具体实施方式
在介绍本申请实施例可以实现的结构之前，先介绍本申请实施例涉及的技术术语。
压电效应：包括正压电效应和逆压电效应，正压电效应指压电材料受到机械力的作用时，其电极化会发生改变；而逆压电效应指对压电材料施加外部电场后，材料会发生变形。压电效应产生的原因主要是压电材料晶体结构自身的各向异性以及极化作用。
主谐振模态、寄生杂模：谐振器所产生的寄生谐振频率位置可能靠近主谐振频率位置，寄生谐振可能影响主谐振模态，进而影响滤波器的带内插损性能和带外抑制性能。谐振器的寄生谐振通常称为杂模，或寄生杂模。当杂模落在主谐振模态附近，例如，落在主谐振模态谐振点和反谐振点附近时，会影响滤波器的带内插损性能和带外抑制性能。
机电耦合系数(Piezoelectric coupling factor)Kt 2：是谐振器的一个关键参数，机电耦合系数Kt 2可以反映机械能与电能间的转换效率，谐振器的机电耦合系数Kt 2决定了谐振器反谐振频率和谐振频率的相对频率宽度。比如，当谐振器运用于滤波器设计中时，这一相对频率宽度直接决定了滤波器的带宽。可以认为，机电耦合系数Kt 2越大，通过梯形结构搭建的滤波器的带宽也可以更大，性能越佳。
机电耦合系数分量kxy 2：对于单晶压电材料，它具有四阶弹性张量c，三阶压电张量e，以及，二阶介电张量ε。根据右手直角坐标系，它分别有弹性张量分量cijkl,压电张量分量eijk,介电张量分量εij，其中i,j,k,l＝{1,2,3}。由于单晶结构的对称性，例如c1323＝c3132，可以简化分量阶数，定义{23,32}→4，{13,31}→5，{12,21}→6，例如c1323＝c3132→c54,则有弹性张量分量cxy(6*6),压电张量分量eix(3*6),介电张量分量εij(3*3)，其中i,j＝{1,2,3}，x,y＝{1,2,3,4,5,6}。机电耦合系数分量kxy 2是由材料的弹性张量分量、压电张量分量、介电张量分量计算得到的，公式为：
其中，x＝{1,2,3},y＝{1,2,3,4,5,6}，εxx S为固定应变下的介电张量分量，cyy E为固定电场强度下的弹性张量分量。
下述解释下各弹性张量分量、压电张量分量、介电张量分量在不同晶体欧拉角时的计算方法和公式。
对于欧拉角为(0,0,0)的压电材料晶向，以LN为例，
cE 11＝2.03,cE 12＝0.53,cE 13＝0.75,cE 14＝0.09,cE 44＝0.60,cE 33＝2.43,cE 22＝cE 11,cE 23＝cE 13,cE 24＝-cE 14,
cE 55＝cE 44,cE 56＝cE 14,cE 66＝(cE 11-cE 12)/2,单位为*1011N/m2；
e15＝3.70,e16＝-2.53,e31＝0.19,e33＝1.31,e21＝e16,e22＝-e16,e24＝e15,e32＝e31,单位为C/m2；
εS 11＝43.6*ε0,εS 33＝29.2*ε0,εS 22＝εS 11,其中ε0为真空介电常数，8.85*10-12F/m。其余分量可通过张量对称性得到，没有数值的分量为零。其中分量为简化形式的表达方法，对于四阶弹性张量分量cE ijkl、三阶压电张量分量eijk，可相应展开得到。
现对于欧拉角为(α,β,γ)的压电材料晶向，其对应的弹性张量分量cE pqrs’、压电张量分量epqr’、介电张量分量εS pq’，可以通过如下公式计算得到：
cE pqrs’＝cE ijklAipAjqAkrAls；
epqr’＝eijkAipAjqAkr；
εS pq’＝εS ijAipAjq；
公式采用爱因斯坦求和约定，其中3*3矩阵A＝(cosαcosγ-sinαcosβsinγ,-cosαsinγ-sin αcosβcosγ,sinαsinβ；sinαcosγ+cosαcosβsinγ,-sinαsinγ+cosαcosβcosγ,-cosαsinβ；sinβsinγ,sinβcosγ,cosβ)。
机电耦合系数Kt 2和机电耦合系数分量kxy 2的关系：机电耦合系数Kt 2由机电耦合系数分量kxy 2和特定谐振器结构所激励的模态所决定。一般来说，谐振器主谐振模态对应的kxy 2越大，谐振器的Kt 2越大。比如，当压电材料选择铌酸锂(lithium niobate,LN)时，LN的最大机电耦合系数分量kxy 2可达到0.9253。利用该分量产生主谐振模态的谐振器拥有整体较大的机电耦合性能，比如谐振器的机电耦合系数Kt 2可以达到25％。并且，一般来说，主谐振模态对应的机电耦合系数分量kxy 2越大，其余机电耦合系数分量kxy 2越小，谐振器表现出更大的机电耦合系数和较小的寄生杂模。
在给定谐振器结构的情况下，一个谐振模态对应一个机电耦合系数分量kxy 2，例如，LN的最大机电耦合系数分量kxy 2可以包括k16 2、k15 2、k34 2、k35 2，激励这些最大机电耦合系数分量kxy 2，产生的模态为主谐振模态，其余机电耦合系数分量产生的模态可以为杂模。比如，在XBAR中，激励最大机电耦合系数分量k16 2，产生主谐振模态零阶水平剪切模态(Zero-order Shear Horizontal mode)SH0模；在XBAR中，激励最大机电耦合系数分量k15 2，产生主谐振模态一阶反对称模态(First-order Anti-symmetry mode)A1模；在YBAR中，激励最大机电耦合系数分量k34 2，产生主谐振模态一阶水平剪切模态(First-order Shear Horizontal mode)SH1模。
品质因数(Quality Factor)Q：代表了器件的能量利用率，即在一个振动周期内，器件接收到的总能量与耗散掉的能量的比值。在滤波器的设计中，构成滤波器的谐振器的机电耦合系数Kt 2与品质因数Q值均为重要的参数。
压电材料的欧拉角(Euler angle)：欧拉角(Euler angle)表征晶圆平面内垂直于或者平行于谐振器指条延伸方向分别与原始压电晶体结构X方向或者Y方向的相对旋转角度关系。
导纳(admittance)：在电力电子学中导纳定义为阻抗(impedance)的倒数，符号Y，单位是西门子，简称西(S)。和阻抗一样，导纳也是一个复数，由实数部分(电导G)和虚数部分(电纳B)组成:Y＝G+jB。
导纳曲线abs和导纳曲线Re：导纳曲线abs(Y)＝|Y|,为Y的模(也成幅值)，代表着谐振器的整体响应。Re(Y)为Y的实部，即电导G，代表着谐振器的损耗。
R-a-R范围：谐振频率(Resonance Frequency)fr和反谐振频率(Anti-resonance Frequency)fa周围的频率范围。示例的，R-a-R范围为(fr-(fa-fr)至(fa+(fa-fr))。
机电耦合R-aR：基于谐振频率fr和反谐振频率fa的相对带宽，以表示谐振器的机电耦合系数。示例的，谐振器的R-aR应与目标滤波器的相对带宽相当。其中，R-aR＝(fa-fr)/((fa+fr)/2)。
本申请实施例提供一种电子设备，该电子设备包括但不限于射频前端、滤波放大模块等产品，还可以包括手机(mobile phone)、平板电脑(pad)、智能穿戴产品(例如，智能手表、智能手环)、虚拟现实(virtual reality，VR)设备、增强现实(augmented reality，AR)、无人机等终端设备，或者也可以是基站、电视、路由器、汽车等设备。本申请实施例对上述电子设备的具体形式不做特殊限制。
在诸如上述的电子设备中，如图1所示，电子设备100可以包括滤波器200，滤波器200可以对信号中特定频率的频点或该频点以外的频率进行有效滤除，得到一个特定频率的信号，或消除一个特定频率后的信号，以提升该电子设备100的工作性能。
图2给出在一些电子设备100中的部分电路图。其中，见图2，该电子设备100包括接收机(Receiver)600、发射机(Transmitter)700、天线(Antenna)500和基带芯片800。天线500通过开关900与接收机600和发射机700分别电连接，以及，接收机600和发射机700分别与基带芯片800电连接。
在图2所示的接收机(Receiver)600中，包括滤波器(Filter)60a和滤波器(Filter)60c，滤波器60a和滤波器60c之间电连接有低噪声放大器60b，滤波器60c通过混频器(Mixer)60d与缓冲器(Buffer)60e电连接，缓冲器60e与压控振荡器60f电连接。图2仅是一种示例性的接收机，可以在此电路结构基础上增加电子器件或者减少电子器件。
在图2所示的发射机(Transmitter)700中，包括功率放大器(power amplifier，PA)70b， 功率放大器70b与滤波器70a和驱动器(Driver)70c分别电连接，驱动器(Driver)70c与压控振荡器70d电连接。类似的，图2仅是一种示例性的发射机，可以在此电路结构基础上增加电子器件或者减少电子器件。
比如，在图2所示的发射机700中，滤波器可以对功率放大器放大后的特定频率的频点或该频点以外的频率进行有效滤除，或者，滤波器可以对低噪声放大器的杂音讯进行滤除。
再如图3所示，滤波器200可以包括多个串联的谐振器300，或者，包括多个并联的谐振器300，又或者，包括串并联相组合的谐振器300。
滤波器200包括的多个谐振器中的至少一个可以为图4所示的谐振器。
如图4，图4展示的是一种谐振器的工艺结构图的部分。其中，该谐振器包括衬底10、第一电极20、压电层30和多个第二电极40。多个第二电极40在第一方向上并排布设，压电层30具有第一侧和第二侧，多个第二电极40位于第一侧，第一电极20和衬底10位于第二侧。示例地，如图4所示，压电层30被堆叠在第一电极20和多个第二电极40之间。
上述图4示例的谐振器中，沿第一方向排布的多个第二电极，该第一方向可以理解为垂直于或者接近垂直于第二电极40延伸方向的方向。在一个实施例中，该第一方向平行于压电层30的延伸方向；或者说，该第一方向垂直于压电层与第一电极、第二电极的堆叠方向。
图4示例结构可以用于体声波谐振器，体声波谐振器主要作用原理是采用压电材料的压电效应特性，利用输入与输出换能器(Transducer)将电波的输入讯号转换成机械能，经过处理后，再把机械能转换成电的讯号，以达到过滤不必要的讯号及杂讯，提升收讯品质的目标。
图4所示的谐振器在工作时，第一电极20可以没有电信号连接，给第二电极40施加一定频率的交变电压，使得沿压电层30的厚度方向，在第一电极20和第二电极40之间产生电场E，压电层30利用该电场形成压电效应。图4示例是利用竖直电场E激发压电层30产生谐振，进而产生电能和机械能之间的转换。
图4所示的谐振器是在压电层30的厚度方向上激发谐振，在一个实施例中，可以被称为一种竖直电场激励的体声波谐振器(Vertically-excited Bulk Acoustic Resonator，YBAR)。这里的压电层30的厚度方向，可以理解为压电层30上平行于多个膜层(衬底、第一电极、压电层)堆叠方向的方向。
图5A和图5B展示的是两种不同结构的谐振器的工艺结构图。在图5A中，衬底10中开设有空腔101，这样的谐振器可以被称为空腔型悬浮压电薄膜谐振器；在图5B中，相比图5A，图5B中的衬底10为没有空腔101的实体结构，并且，相比图5A，可以在第一电极20和衬底10之间堆叠其他层结构，比如，在衬底10和第一电极20之间堆叠介电层50，或者其他功能的层结构，图5B这样的谐振器可以被称为固态衬底压电薄膜谐振器。
或者，可以这样理解如图5A和图5B所示结构，第一电极20具有相对(也可以称为相背离或者相反)的第一面和第二面，第一面相比第二面更加靠近压电层30；在图5A的空腔型悬浮压电薄膜谐振器中，衬底10设有空腔101，第一电极20的第二面的至少部分用于围设空腔101，且第一电极20的至少部分设置于空腔101与压电层30之间；在图5B的固态衬底压电薄膜谐振器中，第一电极20设置于介电层50与压电层30之间，且第一电极20的第二面完全设置在介电层50上。比如，在图5B中，若未设置介电层50，则第一电极20设置于衬底10与压电层30之间，且第一电极20的第二面完全设置在衬底10上。
诸如上述图4、图5A和图5B涉及的不同结构的谐振器，为了使得谐振器被应用在更大的通带带宽中，比如，可以满足Sub-2GHz至Sub-15GHz频段的通带带宽，则需要谐振器具有更大的机电耦合系数Kt 2。
那么，在设计谐振器时，就需要考虑决定机电耦合系数Kt 2大小的机电耦合系数分量kxy 2。比如，在上述图5A和图5B所示结构中，如果压电层30拥有较大的机电耦合系数分量k34 2，例如，机电耦合系数分量k34 2达到0.9253，所对应的一阶水平剪切模态(First-order Shear Horizontal mode)SH1模将作为主谐振模态被激励。如图5A和图5B，在SH1主谐振模态下，振动方向是图5A和图5B所示的方向2，也就是振动方向沿着第二电极40的延伸方向。
图5A和图5B所示结构，利用SH1模尽管可以提供较大的机电耦合系数Kt 2，但是，在谐振 器的主谐振模态谐振点和主谐振模态反谐振点频率范围附近，出现了几种不同类型的寄生模态。例如，见图6A和图6B所示，图6A展示的是图5A所示结构SH1主谐振模态频率附近的导纳曲线，图6B展示的是图5B所示结构SH1主谐振模态频率附近的导纳曲线。
见图6A，展示了当指条间距为p＝0.9μm时，在主谐振模态谐振点和主谐振模态反谐振点之间会产生零阶对称模态(Zero-order Symmetry mode)S0纵波模，作为寄生杂模。该S0纵波模是沿方向1的电场激励机电耦合系数分量k11 2产生的，在S0纵波模下，振动方向是沿方向1，也就是振动方向平行于衬底表面且垂直于第二电极40的延伸方向。
见图6B，展示了当指条间距分别为p＝1μm、p＝1.05μm、p＝1.1μm、p＝1.15μm、p＝1.2μm、p＝1.25μm时，产生的寄生杂模。无论指条间距是较小的1μm，还是较大的1.25μm，寄生杂模落在了主谐振模态谐振点附近。比如，寄生杂模包括S0纵波模和一阶反对称模态(First-order Anti-symmetry mode)A1模，其中，该S0纵波模是沿方向1的电场激励机电耦合系数分量k11 2产生的，在S0纵波模下，振动方向平行于衬底表面且垂直于第二电极40的延伸方向，该A1模是沿方向3的电场激励机电耦合系数分量k35 2产生的，在A1模下，振动方向平行于衬底表面且垂直于第二电极40的延伸方向。
本申请实施例涉及的方向1可以理解为平行于衬底表面且垂直于第二电极40的延伸方向，方向2为平行于第二电极40的延伸方向，方向3为平行于压电层30的厚度方向。
下述涉及的E1为平行于衬底表面且垂直于第二电极40的延伸方向的电场，E2为平行于第二电极40的延伸方向的电场，E3为平行于压电层30的厚度方向的电场。
基于图6A和图6B，利用SH1主谐振模态的谐振器结构中，尽管具有较大的机电耦合系数，可以被应该在更大的通带带宽的设备中，但是，较多其他模态会被激发(比如，A1模、S0纵波模等)，显示为寄生杂模，这些寄生杂模会影响器件(比如滤波器)的通带插损性能和带外抑制性能。
下述本申请实施例还给出了一些谐振器的结构，这些谐振器结构，不仅拥有较高的机电耦合系数，还可以抑制或者频移寄生杂模，优化谐振器性能。
本申请示例的谐振器中，压电层30的压电材料的机电耦合系数分量k35 2数值为多个机电耦合系数分量数值中的较大值或者最大值，例如，k35 2＞0.4。
本申请示例的谐振器中，如图7A，在一些示例中，本申请实施例中的压电层30的压电材料的晶体切割角和传播方向是X切、(120°±30°)Y传播方向；或者，可以理解为压电材料的晶体的欧拉角为(90°，90°，120°±30°)。
上述的X切中的“X”代表压电材料X方向，X切可以用于表示压电材料X方向与压电层30的厚度方向(如图7A中的P方向)为同向，压电材料的传播方向是平行于压电层表面，且垂直于第二电极40的延伸方向，在一个实施例中，压电材料(120°±30°)Y方向与第一方向为同向。
再比如，如图7B，在另外一些示例中，本申请实施例中的压电层30的压电材料的晶体切割角和传播方向是Y切、(90°±30°)X传播方向；或者，压电材料的晶体的欧拉角为(0°，90°，90°±30°)。
上述的Y切中的“Y”代表压电材料Y方向，Y切可以用于表示压电材料Y方向与所述压电层30的厚度方向(如图7B中的P方向)为同向，压电材料(90°±30°)X方向与第一方向为同向。
上述涉及的“同向”定位为允许有一定的误差，可以是接近同向。在一个实施例中，两个角度之间相差5°(包含5°)以内可以看做为接近同向。
本申请实施例涉及的欧拉角、切割角或者传播方向的限定，比如，压电材料切向一般精确度<±0.5°，如：X切±0.5°、Y切±0.5°等。在欧拉角表示下，为(90°±0.5°,90°±0.5°,120°±30°)或(0°±0.5°,90°±0.5°,90°±30°)。
例如，欧拉角可以为(89.5°，90.5°，150°)，或者，欧拉角可以为(89.5°，90.5°，90°)，又或者，欧拉角可以为(89.5°，90.5°，120°)，再或者，欧拉角可以为(89.5°，90°，110°)，再或者，欧拉角可以为(90°，90°，140°)。
例如，欧拉角可以为(0.5°，89.5°，90°)，或者，欧拉角可以为(0°，90.5°，110°)，又或者，欧拉角可以为(0°，90.5°，120°)，再或者，欧拉角可以为(0.5°，90.5°，100°)，再或者， 欧拉角可以为(0.5°，90°，115°)。
当压电材料的欧拉角为(90°，90°，120°±30°)，或者欧拉角为(0°，90°，90°±30°)时，可以使得机电耦合系数分量k35 2具有较大的值，比如，可以使得k35 2＞0.4，或者，0.4＜k35 2＜0.95，又或者，0.4＜k35 2＜0.9253。这样，利用k35 2激励主谐振模态的谐振器也会拥有更大的机电耦合系数Kt 2，比如，机电耦合系数Kt 2可以大于40％。
还有，在电场E3的激励下，机电耦合系数分量k352可以产生A1主谐振模态，在其余机电耦合系数分量下，产生的寄生杂模也会被有效抑制或者频移至工作频率范围之外，抑制情况可以参照下述表一分析。
表一
上述表一展示的内容是：
相关技术中最大k34 2分量，压电材料的晶体的欧拉角为(90°，90°，30°)，激励的主谐振模态为SH1模，各个机电耦合系数分量数值；较大k34 2分量，压电材料的晶体的欧拉角为(0°，90°，0°)，激励的主谐振模态为SH1模，各个机电耦合系数分量数值。
以及，本申请实施例提供的最大k35 2分量，压电材料的晶体的欧拉角为(90°，90°，120°)，激励的主谐振模态为A1模，各个机电耦合系数分量数值；较大k35 2分量，压电材料的晶体的欧拉角为(0°，90°，90°)，激励的主谐振模态为A1模，各个机电耦合系数分量数值。
由上述表一相关技术和本申请实施例提供的数据得知：
基于相关技术的最大k34 2分量一行各个数据，和本申请的最大k35 2分量一行各个数据看出：
采用相关技术中的最大k34 2分量时，最大k34 2分量达到0.9253，但是，电场E1激励机电耦合系数分量K16 2＝0.03，和电场E1激励机电耦合系数分量K11 2＝0.32均会产生寄生杂模，因为激励相关分量的电场为E1。由于E1垂直于指条延伸方向，有较大数值，进而会产生寄生杂模。
但是，采用本申请的最大k35 2分量时，相比上述的最大k34 2分量，最大k35 2分量也可以达到0.9253，具有大机电耦合系数分量K11 2＝0.32转化为K22 2＝0.32，以及，具有大机电耦合系数分量K16 2＝0.03转化为K26 2＝0.03。而激励相关分量的电场为E2，由于电场E2平行于第二电极40的延伸方向，沿着第二电极40的延伸方向，电势基本相同，电场强度基本为零，因此这些机电耦合系数分量激励较小的寄生杂模。
采用相关技术中的较大k34 2分量时，相比最大k34 2分量，较大k34 2分量也可以达到0.5907，但是，电场E1激励机电耦合系数分量K15 2＝0.2218，电场E1激励机电耦合系数分量K16 2＝0.5907会产生寄生杂模
然而，采用本申请的较大k35 2分量时，相比上述的较大k34 2分量，较大k35 2分量也可以达到0.5907，具有大机电耦合系数分量K15 2＝0.2218转化为K24 2＝0.2218，具有大机电耦合系数分量K16 2＝0.5907转化为K26 2＝0.5907，以及，具有大机电耦合系数分量K31 2＝0.08转化为K32 2＝0.08。而在大机电耦合系数分量K24 2、K26 2和K32 2下，激励的电场为电场E2，电场E2沿着第二电极40的延伸方向，电势基本相同，电场强度基本为零，因此这些机电耦合系数分量激励较小的寄生杂模。
上述针对表一数据分析中，也可以利用下述公式确定在一个机电耦合系数分量下，是否会激励出寄生杂模。
谐振模态中振动产生的应力为二阶张量，其各分量大小主要由下面的压电本构方程决定，方程如下：
Tij＝cijmnSmn-ekijEk
其中，i,j,k,m,n＝{1,2,3},T为应力，S为应变，E为电场强度，c为弹性张量，e为压电张量。
基于上述公式，示出了应力Tij与ekijEk相关。
比如，在上述表一的数据中，采用相关技术中的最大k34 2分量时，机电耦合系数分量K16 2＝0.03，激励该机电耦合系数分量K16 2的电场为E1，而电场E1较大，进而在该电场激励下，会激励机电耦合系数分量K16 2产生寄生模态。该示例中，对应上述公式中的下标k值等于1。
再比如，在上述表一的数据中，采用本申请的最大k35 2分量时，机电耦合系数分量K22 2＝0.32，激励该机电耦合系数分量K22 2的电场为E2，而电场E2基本为零，进而在该电场激励下，基本不会激励机电耦合系数分量K22 2产生寄生模态。也就是由于沿第二电极40延伸方向的E2很小，其激励出来的由压电效应产生的应力也会较小，从而就减小了对应谐振模态的振动。该示例中，对应上述公式中的下标k值等于2。
所以，对比相关技术中的k34 2分量，和本申请的k35 2分量，本申请实施例，是将相关技术中的压电材料的晶体晶向绕方向3(即沿着压电层的厚度方向)旋转90°得到本申请的晶向结构，获得最大的k35 2分量，及其在谐振器的结构中得到A1主谐振模态。
下面再结合附图8A和图8B所示的导纳曲线，对本申请涉及的A1模谐振器结构和相关技术中的SH1模谐振器结构寄生杂模抑制情况进行对比。
并且，图8A和图8B针对的是上述所示的空腔型悬浮压电薄膜谐振器进行仿真。
比如，在图8A中，A1模谐振器可以使用X切、120°Y传播方向，压电材料的晶体的欧拉角为(90°，90°，120°)，得到最大的K35 2，而在图8B中，SH1模谐振器可以使用X切、30°Y传播方向，压电材料的晶体的欧拉角为(90°，90°，30°)，得到最大的K34 2。
图8A是采用表二示出的结构限定得到的仿真曲线，图8B采用表三示出的结构限定得到的仿真曲线。
表二
表三
结合图9和图10，图9示出了一种谐振器的工艺结构图，图10示出了图9中第二电极的分布图。在图9中的压电层30的远离第一电极20的一侧，设置有多个第二电极，多个第二电极包括多个第一叉指电极401和多个第二叉指电极402，比如，沿着与第一叉指电极401延伸方向相垂直的方向，多个第一叉指电极401和多个第二叉指电极402可以并排设置，以及，多个第一叉指电极401和多个第二叉指电极402呈间隔排布，即就是，相邻两个第一叉指电极401之间可以设置一个第二叉指电极402。或者，第一叉指电极401和第二叉指电极402在第一方向上间隔，且第一叉指电极401和/或第二叉指电极402的延伸方向垂直于第一方向。
多个第一叉指电极401通过第一汇流条601相连接，多个第二叉指电极402通过第二汇流条602相连接。示例的，第一汇流条601和第二汇流条602相平行布设，并且，第一汇流条601和第二汇流条602，均沿着与第一叉指电极401或者第二叉指电极402延伸方向相垂直的方向延伸，如图10所示的，第一汇流条601和第二汇流条602沿着第一方向延伸。
上述表二和表三中的指条间距(Pitch)P可以理解为图10所示的，每一个第一叉指电极401的宽度为s1，每相邻两个第一叉指电极401和第二叉指电极402之间的间距为s2，指条间距(Pitch)P为宽度s1和间距S2之和。
在一些示例中，多个第一叉指电极401的宽度尺寸s1有工艺容差，以及，相邻两个第一叉指电极401和第二叉指电极402之间的间距s2也有工艺容差。
上述表二和表三中的压电层厚度和第一电极厚度，为沿着多个膜层结构的堆叠方向(如图9的L方向)，压电层30的高度尺寸，第一电极20的高度尺寸。
上述表二和表三中的占工比为第一叉指电极401的宽度s1与指条间距P之间的比值，或者，第二叉指电极402的宽度与指条间距之间的比值。在一些示例中，第一叉指电极401的宽度和第二叉指电极402的宽度相等。
上述表二和表三中的机电耦合系数Kt 2和R-aR均可以表征谐振器的机电耦合性能，机电耦合系数Kt 2和R-aR均越大，机电耦合性能越优。返回至图8A和图8B，分别再详细介绍。
在图8A展示的本申请实施例的导纳曲线中，包括了导纳曲线的模(abs)和实部(Re)，在 A1主谐振模态谐振点和A1主谐振模态反谐振点之间，以及，A1主谐振模态谐振点附近，A1主谐振模态反谐振点附近，基本未出现较大的寄生杂模。以及，在图8A中，还示出了A1主谐振模态的振动方向为平行于衬底且垂直于第二电极40的延伸方向的方向1。
在图8B展示的相关结构的导纳曲线中，在SH1主谐振模态谐振点附近，SH1主谐振模态反谐振点附近，激励出了较大的S0纵波杂模、3阶SV杂模和A1杂模等。
其中，见图8B，主谐振模态SH1的振动方向为平行于第二电极40的延伸方向的方向2，机电耦合系数分量K16 2激励产生的寄生杂模的振动方向是平行于压电层30的厚度方向的方向3，而机电耦合系数分量K11 2激励产生的寄生杂模的振动方向是平行于衬底且垂直于第二电极40的延伸方向的方向1，以及，机电耦合系数分量K35 2激励产生的寄生杂模的振动方向是平行于衬底且垂直于第二电极40的延伸方向的方向1。
基于图8A和图8B，表二和表三对比，明显看出：本申请的A1模谐振器和相关技术中的SH1模谐振器，尽管两种谐振器都拥有约30％的高机电耦合系数。但是，SH1模谐振器中的寄生杂模(例如S0纵向模式、三阶剪切垂直模式、A1模式等)在A1模谐振器中基本上被抑制或被频移到R-a-R范围之外。
下面再结合附图11A和图11B所示的导纳曲线，对本申请涉及的A1模谐振器结构和相关技术中的SH1模谐振器结构寄生杂模抑制情况进行对比。
并且，图11A和图11B针对的是上述固态衬底压电薄膜谐振器进行仿真。
比如，在图11A中，A1模谐振器可以使用X切、120°Y传播方向，压电材料的晶体的欧拉角为(90°，90°，120°)，得到最大的K35 2，而在图11B中，SH1模谐振器可以使用X切、30°Y传播方向，压电材料的晶体的欧拉角为(90°，90°，30°)，得到最大的K34 2。
图11A是采用表四示出的结构限定得到的仿真曲线，图11B采用表五示出的结构限定得到的仿真曲线。
表四
表五
关于表四和表五中的每个膜层结构的解释，可以参照上述表二和表三，对此不再赘述。
在图11A展示的本申请实施例的导纳曲线中，在A1主谐振模态谐振点和A1主谐振模态反谐振点之间，以及，A1主谐振模态谐振点附近，A1主谐振模态反谐振点附近，基本未出现较大的寄生杂模。以及，在图11A中，还示出了A1主谐振模态的振动方向为垂直于第二电极40的延伸 方向的方向1。
在图11B展示的相关结构的导纳曲线中，在SH1主谐振模态谐振点附近，SH1主谐振模态反谐振点附近，激励出了较大的S0纵波杂模和A1杂模等。
其中，见图11B，主谐振模态SH1的振动方向为平行于第二电极40的延伸方向的方向2，机电耦合系数分量K11 2激励产生的寄生杂模的振动方向是平行于衬底且垂直于第二电极40的延伸方向的方向1，以及，机电耦合系数分量K35 2激励产生的寄生杂模的振动方向是平行于衬底且垂直于第二电极40的延伸方向的方向1。
本申请实施例中，激励机电耦合系数分量K35 2产生的A1主谐振模态的主要振动位置位于压电层内部、位于第二电极10的下方。振动方向相对于压电层厚度方向呈一阶反对称形式，即沿压电层厚度方向分为上下两部分，上半部分与下半部分振动方向相反，呈反对称形式。
基于图11A和图11B，表四和表五对比，明显看出：本申请的A1模谐振器和相关技术中的SH1模谐振器，尽管两种谐振器都拥有较高机电耦合系数。但是，SH1模谐振器中的寄生杂模(例如S0纵向模式、A1模式等)在A1模谐振器中基本上被抑制或被频移到R-a-R范围之外。
本申请实施例涉及的通过改变晶向，获得较大的机电耦合系数K35 2，及其在谐振器结构中激励出A1主谐振模态，并且寄生杂模被有效抑制的方案不仅可以被应用在空腔型悬浮压电薄膜谐振器，还可以被应用在固态衬底压电薄膜谐振器结构中，还可以被应用在以下谐振器结构。
图12是本申请实施例提供的一种谐振器工艺结构的部分。其中，该谐振器包括衬底10，形成在衬底10上的介电层50，以及，形成在介电层50的远离衬底10一侧的第一电极20，还有，形成在第一电极20的远离介电层50的一侧的压电层30，形成在压电层30的远离第一电极20一侧的多个第二电极40。
上述实施例提供的谐振器中，衬底10可以采用高声速衬底，比如，可以采用碳化硅(SiC)、金刚石(diamond)、氮化硼(BN)的任意一种，或者多种的组合。
压电层30的材料包括铌和锂的组合、钽和锂的组合中的至少一种组合。比如，压电层30的材料包括钽酸锂(LiTaO3)、铌酸锂(LiNbO3)、氮化铝(AlN)、氧化锌(ZnO)的任意一种，或者多种的组合。
第一电极20可以采用是任何可能的导电金属(包括但不限于Al、Cu、W、Mo、Ru、Pt等)，也可以选择具有高声阻抗的导电金属(包括但不限于W、Ru、Mo、Pt等)，这些具有高声阻抗的金属有助于增加机电耦合系数和提高品质因数Q，进一步提升该谐振器的使用性能。
第二电极40可以采用是任何可能的导电金属(包括但不限于Al、Cu、W、Mo、Ru、Pt等)。第一电极20和第二电极40可以选择相同的导电金属，也可以选择不同的导电金属。
为了增加第一电极20与介电层50之间的连接强度，如图12，可以在介电层50与第一电极20之间堆叠导电连接层60a。
或者，在另外一些示例中，为了增加压电层30与第一电极20之间的连接强度，继续参阅图12，可以在压电层30与第一电极20之间堆叠导电连接层60b。
上述图12中的导电连接层60a和导电连接层60b可以选择相同的材料，也可以选择不同的材料。比如，可以选择任何可能的导电金属(包括但不限于Ti，Cr等)。
在一些示例中，导电连接层的粘接强度可以选择10MPa至40GPa。比如，可以是1.5GPa。
图12示例的压电层30可以选择铌酸锂(LiNbO3)，晶体切割角和传播方向可以是X切、(120°±30°)Y传播方向，压电材料的晶体的欧拉角为(90°，90°，120°±30°)，或者，晶体切割角和传播方向是Y切、(90°±30°)X传播方向，压电材料的晶体的欧拉角为(0°，90°，90°±30°)。这样的话，可以使得该谐振器的机电耦合系数k35 2＞0.4，甚至等于0.9253。进而，整个器件的机电耦合系数可以达到40％左右，可以被应用在更大通带带宽的场景中，比如，可以被应用在拥有较大通带带宽的Sub-6GHz频段中。
继续参阅图12，本申请实施例给出的谐振器结构中，还开设有第一沟槽701，相邻的两个第二电极40之间具有第一间隔，第一沟槽701开设在压电层30中，且第一沟槽701与第一间隔相对，即可以理解为第一沟槽701与第一间隔相贯通。
第一沟槽701可以增加该谐振器的机电耦合系数Kt 2，以及，该第一沟槽701还有助于抑制或 频移寄生模态。
在一些示例中，如图12，第一沟槽701并未将压电层30贯通。在图13示例性的谐振器结构中，第一沟槽701贯通压电层30，延伸至导电连接层60b。
可以理解图13所示结构，压电层30具有相反(或者叫相背对)的底面和顶面，底面相对顶面更加靠近衬底10，在图13中，第一沟槽701自顶面延伸至底面，以贯通该压电层30。
在一些实现结构中，第一沟槽701越深，该谐振器的机电耦合系数Kt 2越高。在本申请实施例中，如图12，可以使得第一沟槽701的深度h满足：30％H≤h≤H，该H为压电层30的厚度尺寸。
还有，在一些可以实现的示例中，图12和图13所示的第一沟槽701自顶面至底面方向，第一沟槽701的径向尺寸逐渐减小。比如，第一沟槽701的倾斜角α可以是：45°≤α≤90°。示例的，在图12和图13中，倾斜角α约在60°左右，在图14中，倾斜角α约在90°左右。
上述第一沟槽701的倾斜角α可以理解为：第一沟槽701的侧面与基准面之间的夹角，该基准面为平行于衬底10表面的平面。
图15是本申请实施例给出的另外一种谐振器的工艺结构图。和上述图12至图14相比，在该实施例中，还包括保护层80，第二电极40的远离压电层30的表面的侧面、第二电极40的侧面、第一沟槽701的侧面和底面均可以被保护层80覆盖住。利用该保护层80可以保护该谐振器免受潜在的腐蚀、划伤、氧化等。
保护层80可以采用介电材料制得，比如，可以采用氧化硅、氮化硅等。
另外，保护层80还可以调整谐振器的机电耦合系数和温度系数(Temperature coefficient of frequency，TCF)等，以进一步的优化该谐振器的工作性能。
为了进一步增大该谐振器的机电耦合系数，如图15，本申请实施中，堆叠在衬底10一侧的介电层50的厚度g可以满足：g＝λ/4，其中，λ为谐振器在谐振频率下的声波在介电层50材料中的波长。
图16是本申请实施例给出的又一种谐振器的工艺结构图。在图16中，衬底10上形成有布拉格反射结构90，第一电极20设置在布拉格反射结构90的远离衬底10的一侧，压电层30堆叠在第一电极20和第二电极40之间，以及，压电层30和第一电极20之间，第一电极20和布拉格反射结构90之间，均堆叠有导电连接层(60a、60b)。
其中，布拉格反射结构90包括多层堆叠的膜层结构，由高声阻抗材料与低声阻抗材料交替堆叠形成。高声阻抗材料包括且不限于：钨(W)、氧化铪(HfO2)、钼(Mo)等；低声阻抗材料包括且不限于：氧化硅(SiO2)等。这些交替的层叠结构对于可能向下传播的声波形成布拉格反射效应，抑制能量向下泄露，提升谐振器的Q值和机电耦合系数。
比如，布拉格反射结构包括堆叠的第一反射层和第二反射层。其中，第一反射层的厚度t1满足：第二反射层的厚度t2满足：λ1为谐振器在谐振频率下的声波在第一反射层材料中的波长，λ2为该声波在第二反射层材料中的波长。
在一些示例中，在另外一些示例中，在又一些示例中，
如果将第一反射层和第二反射层划分为一组，在一些示例中，布拉格反射结构可以包括三组，或者更多组，例如，十组。
上述各个不同的实施例中，形成在压电层30一侧的第二电极40可以如图17所示方式布设，第二电极40包括多个第一叉指电极401和多个第二叉指电极402，多个第一叉指电极401和多个第二叉指电极402可以并排设置，以及，多个第一叉指电极401和多个第二叉指电极402呈间隔排布，即就是，相邻两个第一叉指电极401之间可以设置一个第二叉指电极402。
多个第一叉指电极401通过第一汇流条601相连接，多个第二叉指电极402通过第二汇流条602相连接。
当采用上述涉及的衬底为固态高声速衬底，比如，固态高声速衬底可以是金刚石(diamond)、碳化硅(SiC)、氮化硼(BN)中的至少一种时，指条间距P可以满足p<Vs/2f，其中Vs是衬底 10中的剪切体波声速，f是谐振器的工作频率。这样可以防止能量朝衬底10方向泄露，提升谐振器的Q值和机电耦合系数。
在一些示例中，如图17，第一汇流条601和第二汇流条602相平行布设，并且，可以沿着与第二电极的延伸方向相垂直的方向延伸。
第一汇流条601可以作为输入端，第二汇流条602可以作为输出端。比如，可以通过第一汇流条601向多个第一叉指电极401输入一定频率范围的交变电压，通过第二汇流条602向多个第二叉指电极402输出经过谐振器处理后的交变电压信号。
还有，在多个第一叉指电极401和多个第二叉指电极402的旁侧还设置有反射栅。比如，如图17，示出了反射栅110和反射栅120，反射栅110和反射栅120可以将向外传播的声能反射回来，将声波谐振能量主要集中在谐振器的第二电极所在的区域。
继续参阅图17，反射栅包括多个平行布设的栅条10a，栅条10a的延伸方向与第二电极40的延伸方向一致。这里的延伸方向一致(或者为延伸方向相同)，可以理解为有一定的工艺误差，比如，之间的角度可以为2°以内。
反射栅还包括连接条10b，多个栅条10a的一端通过一个连接条10b连接，多个栅条10a的另一端通过另一个连接条10b连接。
如图17，相邻两个栅条10a之间的间距t满足：0.3≤t/p≤0.7；p为指条间距。比如，t/p＝0.5，等。当两个栅条10a之间的间距t满足上述条件时，可以更好的将向外传播的声能反射回来，提高谐振器的品质因数Q。
另外，如图18，图18是图17沿A-A方向剖切的剖面图。其中，在谐振器的端部，压电层30的侧壁可以呈竖直结构，利用竖直的压电层侧壁可以反射向外传播的声能，提高谐振器的品质因数Q。
上述图18中的压电层30的侧壁，可以理解为靠近多个第二电极40端部的侧壁，该侧壁垂直于衬底的表面，并且平行于第二电极的延伸方向。
上述图12至图18展示的是固态衬底压电薄膜谐振器，图19A和图19B分别展示的是空腔型悬浮压电薄膜谐振器。在图19A中，衬底10与第一电极20相对的位置处开设有空腔101，空腔101贯通衬底10，使得谐振器工作区域的第一电极20的远离压电层30的表面的至少部分呈悬浮(或者叫悬空)状态。在图19B中，图19B和图19A的区别在于：在图19B中，空腔101并未将衬底10贯通，和上述图19A类似的是：使得谐振器工作区域的第一电极20的远离压电层30的表面的至少部分呈悬浮(或者叫悬空)状态。
和上述固态衬底压电薄膜谐振器类似，在图19A和图19B示例的空腔型悬浮压电薄膜谐振器中，也可以在压电层30内开设第一沟槽701，以及，也可以具有覆盖第二电极40的表面和侧面，以及覆盖第一沟槽701的侧面和底面的保护层。
在上述涉及的如图19A和图19B展示的空腔型悬浮压电薄膜谐振器中，如图20，当指条间距与压电层厚度之比增加时，机电耦合系数会随之增加，例如，机电耦合系数可以达到42.75％。进而，空腔型悬浮压电薄膜谐振器中，指条间距P与压电层的厚度d的比值：1≤P/d，或者，1≤P/d≤30，又或者，1≤P/d≤20，又或者，1≤P/d≤10，使得该谐振器拥有较大的机电耦合系数。
无论是本申请实施例涉及的空腔型悬浮压电薄膜谐振器，还是固态衬底压电薄膜谐振器，如图21，用于与输入端电连接的第一叉指电极的端部可以设计为加厚结构，或者可以设计为加宽结构。这样，可以抑制该谐振器的横模，进一步的优化该谐振器的工作性能。
比如，见图21和图22，图22是沿着图21的B-B方向剖切的剖视图。其中，与第一汇流条601连接的第一叉指电极401A中，第一叉指电极401A的远离第一汇流条601的端部的厚度尺寸D1，大于第一叉指电极401A的其余部分的厚度尺寸D2，且120％≤D1/D2≤300％。示例的，D1/D2＝150％，或者，D1/D2＝200％，又或者，D1/D2＝250％。
再比如，继续见图21和图23，图23展示的是图21中的第一叉指电极401B的细节图。与第一汇流条601连接的第一叉指电极401B中，第一叉指电极401B的远离第一汇流条601的端部的宽度尺寸h1，大于第一叉指电极401B的其余部分的宽度尺寸h2；且100％＜h1/h2≤200％。示例的，h1/h2＝150％，或者，h1/h2＝180％。这里的宽度尺寸为垂直于第一叉指电极401B延伸方向 的尺寸。
如图24，图24是沿着图21的C-C方向剖切的剖视图，一并结合图21和图24，第二电极的尖端与汇流条之间具有第二间隔，压电层30的与该第二间隔相对的位置处具有第二沟槽702，该第二沟槽702与第二间隔相贯通，比如，在图24中，第二叉指电极402的远离第二汇流条602的尖端与第一汇流条601之间具有第二间隔，并且，与该第二间隔相对的压电层30部分也被去掉(比如，可以被刻蚀掉)，通过将该区域的压电层30去掉至少部分，可以抑制横模，进一步的优化该谐振器的性能。
本申请实施例还给出了一种谐振器的制备方法，该谐振器制备方法包括：
制得第一电极、压电层和多个第二电极，多个第二电极在第一方向上并排布设，压电层设置在第一电极和多个第二电极之间，第一电极相比多个第二电极更加靠近衬底。
其中，压电层的压电材料的晶体切割角和传播方向是X切、(120°±30°)Y传播方向，压电材料的晶体的欧拉角为(90°，90°，120°±30°)；或者，压电材料的晶体切割角和传播方向是Y切、(90°±30°)X传播方向，压电材料的晶体的欧拉角为(0°，90°，90°±30°)；压电材料X方向与压电层的厚度方向为同向，压电材料(120°±30°)Y方向与第一方向为同向；压电材料Y方向与压电层的厚度方向为同向，压电材料(90°±30°)X方向与第一方向为同向。
该第一电极的材料可以包括任何可能的导电金属(包括但不限于Be、Al、Cu、W、Mo、Ru、Pt等)。示例的，可以选择具有高声阻抗的金属(包括但不限于W、Ru、Mo、Pt等)，这样有助于增加制得的谐振器的机电耦合系数，和提高谐振器的品质因数Q。
压电层30的材料包括钽酸锂(LiTaO3)、铌酸锂(LiNbO3)、氮化铝(AlN)、氧化锌(ZnO)中的至少一种。
下述分别给出了制备空腔型悬浮压电薄膜谐振器，和固态衬底压电薄膜谐振器的制备工艺步骤。
如图25A至图25C，展示的是制备固态衬底压电薄膜谐振器时，每一步骤对应的工艺结构图。
见图25A，在压电晶圆的一侧依次形成第一电极20和介电层50。
见图25B，将堆叠有第一电极20和介电层50的压电晶圆倒置，并与衬底10键合。以及，可以采用离子注入切割(ion implantation cutting)或化学机械平坦化(Chemical-mechanical polishing,CMP)方法对压电晶圆进行厚度减薄，减薄至目标厚度，形成压电层30。
见图25C，在压电层30的远离第一电极20的一侧形成多个并排设置的第二电极40。从而，制得固态衬底压电薄膜谐振器。
图25A至图25C，仅展示了固态衬底压电薄膜谐振器制备方法中一些步骤。在其他一些可以实现的工艺步骤中，在执行图25A所示步骤时，也可以在衬底10的一侧形成布拉格反射结构，在执行图25B所示步骤时，布拉格反射结构与介电层50键合。或者，在另外一些可以实现的工艺步骤中，可以在压电层30内开设沟槽，比如，可以采用刻蚀工艺在压电层30中刻蚀出沟槽，该沟槽有助于进一步的抑制或者频移寄生杂模，并增加该谐振器的机电耦合系数。又或者，在一些可以实现的工艺步骤中，也可以在介电层50和第一电极20之间形成导电连接层，从而，提升该谐振器膜层之间的连接强度。
在制备多个第二电极时，可以制得第一汇流条和第二汇流条，第一汇流条连接多个第二电极中的多个第一叉指电极，第二汇流条连接多个第二电极中的多个第二叉指电极。
以及，也可以对第二电极的端部进行加厚，或者加宽。
如图26A至图26E，展示的是制备空腔型悬浮压电薄膜谐振器时，每一步骤对应的工艺结构图。
图26A，将压电晶圆与衬底10键合。在一些示例中，压电晶圆和衬底10之间还可以有介电层。
图26B，可以采用离子注入切割(ion implantation cutting)或化学机械平坦化(Chemical-mechanical polishing,CMP)方法对压电晶圆进行厚度减薄，减薄至目标厚度，形成压电层30。
见图26C，在压电层30的远离第一电极20的一侧形成多个并排设置的第二电极40。
见图26D，在衬底10内开设空腔101，并使得空腔101贯通至压电层30。以及，该步骤中，空腔101需要开设在多个第二电极40所处谐振区域的下方。
见图26E，在空腔101的靠近压电层30的底面形成第一电极20。从而，制得空腔型悬浮压电薄膜谐振器。
当然，图26A至图26E，仅展示了空腔型悬浮压电薄膜谐振器制备方法中一些步骤。还可以增加一些工艺步骤，比如，可以采用刻蚀工艺在压电层30中刻蚀出沟槽，该沟槽有助于进一步的抑制或者频移寄生杂模，并增加该谐振器的机电耦合系数。在制备多个第二电极时，可以制得第一汇流条和第二汇流条，第一汇流条连接多个第二电极中的多个第一叉指电极，第二汇流条连接多个第二电极中的多个第二叉指电极。也可以对第二电极的端部进行加厚，或者加宽。诸如上述涉及的空腔型悬浮压电薄膜谐振器，或者固态衬底压电薄膜谐振器，可以作为传感器，比如，可以是温度、湿度传感器、压力传感器等。或者，还可以作为延迟线器件，应用于100MHz-30GHz等各类高频信号处理中等。
还有，上述涉及的空腔型悬浮压电薄膜谐振器，或者固态衬底压电薄膜谐振器，可以如图27所示的以梯形结构实现电连接，以实现用于射频通信的滤波器。在滤波器中，可以有相互串联的谐振器，也可以有相互并联的谐振器，并联的谐振器的谐振频率可以低于串联的谐振器的谐振频率，比如，上述谐振器工艺结构中的较厚的压电层30或较厚的保护层80或较大的指条间距P，可以降低谐振器的谐振频率。
图27示例中，包括谐振器301、谐振器302、谐振器303、谐振器304和谐振器305，谐振器301、谐振器302、谐振器303为串联谐振器，谐振器304和谐振器305为并联谐振器。谐振器301至谐振器305中的至少一个谐振器，可以是上述实施例涉及的谐振器。
在一些示例中，如图28，图28展示的是图27中梯形滤波器各个谐振器的导纳曲线与滤波器传输损耗曲线的关系。见图28，串联谐振器(如谐振器301、谐振器302和谐振器303)的谐振点和并联谐振器(如谐振器304和谐振器305)的反谐振点位于通带频段内，形成该滤波器通带，串联谐振器(如谐振器301、谐振器302和谐振器303)的反谐振点位于通带外高频侧，并联谐振器(如谐振器304和谐振器305)的谐振点位于通带外低频侧，从而，使得滤波器形成高滚降和高带外抑制的特点。
滤波器中，在可以实现的工艺结构中，可以将本申请实施例提供的多个谐振器集成在同一衬底10上，比如，如图29，相串联的谐振器410、谐振器420和谐振器430被集成在衬底10上，谐振器410和谐振器420之间通过导电连接层130电连接，以及谐振器420和谐振器430之间通过导电连接层140电连接。
导电连接层130或者导电连接层140具有多种可以实现的结构。
比如，如图30，图30体现了如何将声波谐振器410与导电连接层130连接，并且图30展示的是固态衬底压电薄膜谐振器中导电连接层130的设置方式。具体的，如图30，在制得堆叠的第一电极20、压电层30和第二汇流条602之后，在第二汇流条602的远离衬底10的一侧形成介电层150，该介电层150不仅形成在第二汇流条602一侧，还覆盖两个声波谐振器之间的区域，并且，在介电层150内刻蚀贯通至第二汇流条602的孔151，再在介电层150的远离第二汇流条602的一侧，以及介电层150的孔151内形成导电材料，以形成与第二汇流条602电连接的导电连接部130。这样的话，通过导电连接层130电连接两个声波谐振器。
再比如，如图31，图31同样体现了如何将声波谐振器410与导电连接层130连接，并且图31也展示的是固态衬底压电薄膜谐振器中导电连接层130的设置方式。图31和图30所示结构的区别在于：在图30中，导电连接部130相比介电层150远离第二汇流条602设置，而在图31中，导电连接部130相比介电层150更加靠近第二汇流条602，即在图31中，导电连接部130堆叠在介电层150和第二汇流条602之间，与第二汇流条602直接接触，以实现电连接。
在图31中，为了避免导电连接部130与第一电极20电连接，在第一电极20的靠近导电连接部130的位置处形成有空隙201，实现第一电极20与导电连接部130的电隔离。
上述导电连接层(也可以叫Pad层)的材料可以是任何导电金属(包括但不限于Al、Cu等)。
还有，如图29，第二汇流条602和导电连接层(Pad层)130之间添加介电层150(包括但不 限于SiO2、SiN、聚酰亚胺、光刻胶等)，以避免产生相应的寄生效应。
上述本申请实施例涉及的滤波器还可以被应用在双工器，或者多工器中。在双工器中，包括发射通道滤波器和接收通道滤波器，该发射通道滤波器和接收通道滤波器中的至少一个可以采用上述的滤波器进行滤波。在多工器中，包括多个发射通道滤波器和多个接收通道滤波器，其中，多个发射通道滤波器中的至少一个，或者多个接收通道滤波器中的至少一个可以采用本申请实施例涉及的滤波器。
在本说明书的描述中，具体特征、结构、材料或者特点可以在任何的一个或多个实施例或示例中以合适的方式结合。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (34)

  1. 一种谐振器，其特征在于，包括：
    衬底；
    第一电极、压电层和多个第二电极，所述多个第二电极在第一方向上并排布设，所述压电层具有第一侧和第二侧，所述多个第二电极位于所述第一侧，所述第一电极和所述衬底位于所述第二侧；
    所述压电层包括压电材料；
    所述压电材料的晶体的欧拉角为(90°，90°，120°±30°)，或者，所述压电材料的晶体切割角和传播方向是X切、(120°±30°)Y传播方向，其中，所述压电材料X方向与所述压电层的厚度方向为同向，所述压电材料(120°±30°)Y方向与所述第一方向为同向；
    或者，
    所述压电材料的晶体的欧拉角为(0°，90°，90°±30°)，或者，所述压电材料的晶体切割角和传播方向是Y切、(90°±30°)X传播方向，其中，所述压电材料Y方向与所述压电层的厚度方向为同向，所述压电材料(90°±30°)X方向与所述第一方向为同向。
  2. 根据权利要求1所述的谐振器，其特征在于，相邻两个所述第二电极之间具有第一间隔；
    所述压电层与所述第一间隔相对的位置处具有第一沟槽，所述第一沟槽与所述第一间隔贯通。
  3. 根据权利要求2所述的谐振器，其特征在于，所述压电层具有位于所述第二侧的底面和位于所述第一侧的顶面，所述第一沟槽贯通所述底面和所述顶面。
  4. 根据权利要求1-3中任一项所述的谐振器，其特征在于，所述第一电极具有相对的第一面和第二面，所述第一面相比所述第二面更加靠近所述压电层；
    所述衬底设有空腔，所述第一电极的所述第二面的至少部分用于围设所述空腔，且所述第一电极的至少部分设置于所述空腔与所述压电层之间。
  5. 根据权利要求4所述的谐振器，其特征在于，所述谐振器的机电耦合系数Kt 2≥20％。
  6. 根据权利要求4或5所述的谐振器，其特征在于，所述谐振器还包括：第一汇流条和第二汇流条；
    所述多个第二电极中每相邻两个第二电极中一个为第一叉指电极，另一个为第二叉指电极；所述第一叉指电极和所述第二叉指电极在所述第一方向上间隔，且所述第一叉指电极和/或所述第二叉指电极的延伸方向垂直于所述第一方向；
    所述多个第二电极中的多个所述第一叉指电极通过所述第一汇流条连接，所述多个第二电极中的多个所述第二叉指电极通过所述第二汇流条连接；
    指条间距P与所述压电层的厚度d满足：P/d≥0.5；
    每个所述第一叉指电极的宽度尺寸为s1，每相邻两个所述第一叉指电极和所述第二叉指电极之间的间距为s2，所述指条间距P＝s1+s2，所述宽度尺寸为平行于所述衬底的表面且垂直于所述第一叉指电极延伸方向的尺寸。
  7. 根据权利要求1-3中任一项所述的谐振器，其特征在于，所述第一电极具有相对的第一面和第二面，所述第一面相比所述第二面更加靠近所述压电层；
    所述第一电极设置于所述衬底与所述压电层之间，且所述第一电极的所述第二面完全设置在所述衬底上。
  8. 根据权利要求7所述的谐振器，其特征在于，所述谐振器的机电耦合系数Kt 2≥10％。
  9. 根据权利要求7或8所述的谐振器，其特征在于，所述谐振器还包括：第一汇流条和第二汇流条；
    所述多个第二电极中每相邻两个第二电极中一个为第一叉指电极，另一个为第二叉指电极；所述第一叉指电极和所述第二叉指电极在所述第一方向上间隔，且所述第一叉指电极和/或所述第二叉指电极的延伸方向垂直于所述第一方向；
    所述多个第二电极中的多个所述第一叉指电极通过所述第一汇流条连接，所述多个第二电极中的多个所述第二叉指电极通过所述第二汇流条连接；
    指条间距P满足：其中：Vs是所述衬底的剪切体波声速，f是所述谐振器的工作频率；
    每个所述第一叉指电极的宽度尺寸为s1，每相邻两个所述第一叉指电极和所述第二叉指电极之间的间距为s2，所述指条间距P＝s1+s2，所述宽度尺寸为平行于所述衬底的表面且垂直于所述第一叉指电极延伸方向的尺寸。
  10. 根据权利要求9所述的谐振器，其特征在于，所述衬底包括碳化硅、氮化硼、金刚石中的至少一种。
  11. 根据权利要求9或10所述的谐振器，其特征在于，所述衬底的厚度尺寸Z满足：Z≥4d，d为所述压电层的厚度尺寸，所述衬底的厚度尺寸和所述压电层的厚度尺寸均为垂直于所述衬底表面的方向上的尺寸。
  12. 根据权利要求7或8所述的谐振器，其特征在于，所述谐振器还包括：
    堆叠的第一反射层和第二反射层；
    所述第一反射层和所述第二反射层设置在所述衬底和所述第一电极之间；
    其中，所述第一反射层的厚度t1满足：
    所述第二反射层的厚度t2满足：
    其中，λ1为所述谐振器在谐振频率下的声波在所述第一反射层材料中的波长；
    λ2为所述声波在所述第二反射层材料中的波长。
  13. 根据权利要求7-12中任一项所述的谐振器，其特征在于，所述衬底和所述第一电极之间堆叠有介电层，所述介电层的厚度g满足：g＝λ/4，其中，λ为所述谐振器在谐振频率下的声波在所述介电层的材料的波长。
  14. 根据权利要求7-13中任一项所述的谐振器，其特征在于，所述谐振器还包括：第一汇流条和第二汇流条；
    所述多个第二电极中每相邻两个第二电极中一个为第一叉指电极，另一个为第二叉指电极；所述第一叉指电极和所述第二叉指电极在所述第一方向上间隔，且所述第一叉指电极和/或所述第二叉指电极的延伸方向垂直于所述第一方向；
    所述多个第二电极中的多个所述第一叉指电极通过所述第一汇流条连接，所述多个第二电极中的多个所述第二叉指电极通过所述第二汇流条连接；
    指条间距P与所述压电层的厚度d满足：P/d≥1；
    每个所述第一叉指电极的宽度尺寸为s1，每相邻两个所述第一叉指电极和所述第二叉指电极之间的间距为s2，所述指条间距P＝s1+s2，所述宽度尺寸为平行于所述衬底的表面且垂直于所述第一叉指电极延伸方向的尺寸。
  15. 根据权利要求1-14中任一项所述的谐振器，其特征在于，所述谐振器还包括：导电连接层；
    所述导电连接层堆叠在所述第一电极和所述压电层之间。
  16. 根据权利要求1-15中任一项所述的谐振器，其特征在于，所述多个第二电极的至少部分第二电极包括第一端部和第二端部，所述第一端部的厚度尺寸D1和所述第二端部的厚度尺寸D2满足120％≤D1/D2≤300％。
  17. 根据权利要求1-16中任一项所述的谐振器，其特征在于，所述多个第二电极的至少部分第二电极包括第一端部和第二端部，所述第一端部的宽度尺寸h1和所述第二端部的宽度尺寸h2满足100％＜h1/h2≤200％；所述宽度尺寸为平行于所述衬底的表面且垂直于所述第二电极延伸方向的尺寸。
  18. 根据权利要求1-17中任一项所述的谐振器，其特征在于，所述谐振器还包括：第一汇流条和第二汇流条；
    所述多个第二电极中每相邻两个第二电极中一个为第一叉指电极，另一个为第二叉指电极；所述第一叉指电极和所述第二叉指电极在所述第一方向上间隔，且所述第一叉指电极和/或所述第二叉指电极的延伸方向垂直于所述第一方向；
    所述多个第二电极中的多个所述第一叉指电极通过所述第一汇流条连接，所述多个第二电极 中的多个所述第二叉指电极通过所述第二汇流条连接；
    所述第一叉指电极的与所述第一汇流条连接的端部为指条连接端，另一端为指条尖端，所述指条尖端与所述第二汇流条之间具有第二间隔；
    所述压电层与所述第二间隔相对的位置处具有第二沟槽，所述第二沟槽与所述第二间隔贯通。
  19. 根据权利要求1-18中任一项所述的谐振器，其特征在于，所述谐振器还包括多个平行布设的栅条，多个所述栅条的一端通过第一连接条连接，多个所述栅条的另一端通过第二连接条连接，所述栅条的延伸方向与所述第二电极的延伸方向相同；
    所述多个第二电极中每相邻两个第二电极中一个为第一叉指电极，另一个为第二叉指电极，所述第一叉指电极和所述第二叉指电极在所述第一方向上间隔，且所述第一叉指电极和/或所述第二叉指电极的延伸方向垂直于所述第一方向；所述多个第二电极中的多个所述第一叉指电极通过第一汇流条连接，所述多个第二电极中的多个所述第二叉指电极通过第二汇流条连接；
    相邻两个所述栅条之间的间距t满足：0.3≤t/P≤0.7；
    所述P为指条间距，每个所述第一叉指电极的宽度尺寸为s1，每相邻两个所述第一叉指电极和所述第二叉指电极之间的间距为s2，所述指条间距P＝s1+s2，所述宽度尺寸为平行于所述衬底的表面且垂直于所述第一叉指电极延伸方向的尺寸。
  20. 根据权利要求1-19中任一项所述的谐振器，其特征在于，所述压电层包括相对的第一侧壁和第二侧壁；
    所述第一侧壁和/或所述第二侧壁为垂直于所述衬底表面、且平行于所述第二电极延伸方向的平面。
  21. 根据权利要求1-20中任一项所述的谐振器，其特征在于，所述压电层的材料包括铌和锂的组合、钽和锂的组合中的至少一种组合；
    所述第一电极的材料包括钨、铂、钼、铝中的至少一种。
  22. 根据权利要求1-21中任一项所述的谐振器，其特征在于，所述压电材料具有多个机电耦合系数分量，机电耦合系数分量k35 2的数值为所述多个机电耦合系数分量数值中的最大值。
  23. 根据权利要求22所述的谐振器，其特征在于，所述机电耦合系数分量k35 2满足，0.4＜k35 2。
  24. 根据权利要求22或23所述的谐振器，其特征在于，所述机电耦合系数分量k35 2满足，0.4＜k35 2＜0.95。
  25. 根据权利要求22-24中任一项所述的谐振器，其特征在于，
    基于给所述多个第二电极施加电压，所述谐振器用于在激励所述压电材料的所述机电耦合系数分量k35 2时产生一阶反对称模态，所述一阶反对称模态的振动方向平行于所述衬底的表面且垂直于所述第二电极的延伸方向。
  26. 根据权利要求25所述的谐振器，其特征在于，
    所述谐振器用于在激励所述机电耦合系数分量k35 2之外的至少部分机电耦合系数分量的电场平行于所述第二电极的延伸方向；
    所述至少部分机电耦合系数分量包括：机电耦合系数分量k21 2、k22 2、k23 2、k24 2、k25 2和k26 2中的至少一种。
  27. 一种谐振器，其特征在于，包括：
    衬底；
    第一电极、压电层和多个第二电极，所述多个第二电极并排布设，所述压电层具有第一侧和第二侧，所述多个第二电极位于所述第一侧，所述第一电极和所述衬底位于所述第二侧；
    所述压电层包括压电材料，所述压电材料的机电耦合系数分量k35 2的数值满足：k35 2＞0.4。
  28. 根据权利要求27所述的谐振器，其特征在于，所述压电材料具有多个机电耦合系数分量，所述机电耦合系数分量k35 2的数值为所述多个机电耦合系数分量数值中的最大值。
  29. 根据权利要求28所述的谐振器，其特征在于，所述机电耦合系数分量k35 2满足，0.4＜k35 2。
  30. 根据权利要求28或29所述的谐振器，其特征在于，所述机电耦合系数分量k35 2的数值满足：0.4＜k35 2＜0.95。
  31. 根据权利要求27-30中任一项所述的谐振器，其特征在于，
    基于给所述多个第二电极施加电压，所述谐振器用于在激励所述压电材料的所述机电耦合系数分量k35 2时产生一阶反对称模态，所述一阶反对称模态的振动方向平行于所述衬底的表面且垂直于所述第二电极的延伸方向。
  32. 根据权利要求31所述的谐振器，其特征在于，
    所述谐振器用于在激励所述机电耦合系数分量k35 2之外的至少部分机电耦合系数分量的电场平行于所述第二电极的延伸方向；
    所述至少部分机电耦合系数分量包括：机电耦合系数分量k21 2、k22 2、k23 2、k24 2、k25 2和k26 2中的至少一种。
  33. 一种滤波器，其特征在于，包括：
    多个电连接的谐振器，多个所述谐振器中的至少一个谐振器为权利要求1-32中任一项所述的谐振器。
  34. 一种电子设备，其特征在于，包括：
    控制电路；
    如权利要求1-32中任一项所述的谐振器，或者权利要求33所述的滤波器，所述谐振器或者所述滤波器与所述控制电路电连接。
PCT/CN2023/133797 2023-01-20 2023-11-23 谐振器、滤波器、电子设备 WO2024152737A1 (zh)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010157956A (ja) * 2009-01-05 2010-07-15 Panasonic Corp 弾性表面波デバイス
CN113708739A (zh) * 2021-08-27 2021-11-26 中国科学院上海微系统与信息技术研究所 一种声波滤波器
CN114221633A (zh) * 2021-12-17 2022-03-22 中国科学技术大学 高频高q值的声波谐振器及其制作方法
CN115395918A (zh) * 2022-10-27 2022-11-25 中国科学技术大学 声波谐振器及其设计方法、制造方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010157956A (ja) * 2009-01-05 2010-07-15 Panasonic Corp 弾性表面波デバイス
CN113708739A (zh) * 2021-08-27 2021-11-26 中国科学院上海微系统与信息技术研究所 一种声波滤波器
CN114221633A (zh) * 2021-12-17 2022-03-22 中国科学技术大学 高频高q值的声波谐振器及其制作方法
CN115395918A (zh) * 2022-10-27 2022-11-25 中国科学技术大学 声波谐振器及其设计方法、制造方法

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