WO2022007234A1 - 谐振器 - Google Patents

谐振器 Download PDF

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Publication number
WO2022007234A1
WO2022007234A1 PCT/CN2020/122195 CN2020122195W WO2022007234A1 WO 2022007234 A1 WO2022007234 A1 WO 2022007234A1 CN 2020122195 W CN2020122195 W CN 2020122195W WO 2022007234 A1 WO2022007234 A1 WO 2022007234A1
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WIPO (PCT)
Prior art keywords
electrode
longitudinal
region
piezoelectric
film
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PCT/CN2020/122195
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English (en)
French (fr)
Inventor
窦韶旭
吕丽英
杨帅
吴一雷
韩琦
吴珂
王超
Original Assignee
瑞声声学科技(深圳)有限公司
瑞声科技（南京）有限公司
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Publication of WO2022007234A1 publication Critical patent/WO2022007234A1/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
    • H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
    • H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
    • H03H9/171—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type
    • H03H9/172—Means for mounting on a substrate, i.e. means constituting the material interface confining the waves to a volume
    • H03H9/173—Air-gaps

Definitions

  • the present invention relates to the technical field of resonators, and in particular, to a resonator.
  • the resonator includes a substrate, a first electrode, a piezoelectric film and a second electrode stacked along a first direction, and a longitudinal acoustic wave reflector is arranged between the substrate and the first electrode; the longitudinal acoustic wave
  • the area enclosed by the inner edge of the orthographic projection of the reflector along the first direction is the resonance area
  • the area enclosed by the projection of the second electrode along the first direction is the excitation area
  • longitudinal acoustic waves will be generated in the excitation area and transverse sound waves.
  • An object of the present invention is to provide a resonator with reduced energy loss and increased Q value.
  • the present invention provides a resonator, which includes a substrate, a composite film disposed on the substrate along a first direction, and a longitudinal acoustic wave reflector disposed on the side of the composite film close to the substrate;
  • the composite film comprises a first electrode, a piezoelectric functional film, a second electrode and a frequency modulator arranged in sequence along the first direction, the first electrode being arranged on the substrate and the longitudinal acoustic wave reflector;
  • the frequency modulator comprises a frequency modulation main body part stacked on a side of the second electrode away from the base, and a convex ring extending from the periphery of the frequency modulation main body to a direction away from the base;
  • the area surrounded by the orthographic projection of the inner surface of the convex ring to the second electrode along the first direction is a resonance area, and the area where the resonator is located outside the resonance area is a non-resonance area;
  • the first An electrode, the piezoelectric functional film and the second electrode all completely cover the resonant region;
  • the piezoelectric functional film includes an electrode located in the resonant region and disposed on the side of the first electrode away from the substrate a longitudinal piezoelectric film and a longitudinal non-piezoelectric film surrounding the outer periphery of the longitudinal piezoelectric film and disposed on the side of the first electrode away from the substrate;
  • the acoustic impedance of the part of the resonator located in the resonance region is different from the acoustic impedance of the part of the resonator located in the non-resonant region, and the first electrode, the piezoelectric functional film, the The acoustic impedances of the two electrodes and the part of the frequency modulation main body located in the resonance region are substantially constant.
  • the convex ring is located in the non-resonant region; the first electrode, the piezoelectric functional film and the second electrode all extend at least partially into the non-resonant region.
  • the convex ring includes at least two and is spaced apart from each other.
  • the longitudinal acoustic wave reflector is a cavity structure formed by a side of the substrate close to the first electrode that is recessed in a direction away from the first electrode.
  • the longitudinal acoustic wave reflector is a Bragg acoustic reflector disposed on a side of the substrate close to the first electrode, and the first electrode is disposed on a side of the Bragg acoustic reflector away from the substrate.
  • the orthographic projection of the inner surface of the convex ring to the longitudinal acoustic wave reflector along the first direction falls within the range of the longitudinal acoustic wave reflector.
  • the orthographic projection of the longitudinal piezoelectric film to the convex ring along the first direction completely falls within the resonance region.
  • the part of the composite film that falls within the region enclosed by the outer side surface of the longitudinal piezoelectric film along the first direction forms an excitation region, and the excitation region is located in the resonance region.
  • the longitudinal piezoelectric film has a piezoelectric coefficient along the first direction, and the piezoelectric coefficient of the longitudinal non-piezoelectric film along the first direction is zero or smaller than the longitudinal piezoelectric film along the first direction.
  • the piezoelectric coefficient in the first direction is described.
  • the frequency modulator includes a frequency modulation main body part stacked on the side of the second electrode away from the substrate, and a convex ring extending from the periphery of the frequency modulation main body part to the direction away from the substrate; the convex ring
  • the area surrounded by the orthographic projection of the inner side of the resonator to the second electrode along the first direction is the resonance area, and the area where the resonator is located outside the resonance area is the non-resonant area;
  • the first electrode, the piezoelectric functional film and the second electrode are completely covered Resonance area;
  • the piezoelectric functional film includes a longitudinal piezoelectric film located in the resonance area and disposed on the side of the first electrode away from the substrate, and a longitudinal non-piezoelectric film surrounding the outer periphery of the longitudinal piezoelectric film and disposed on the side of the first electrode away from the substrate film; the acoustic impedance of the part of the
  • the side surface acts as the interface between the resonant area and the non-resonant area, so that the acoustic impedance of the composite film on both sides of the inner side of the convex ring is discontinuous, and during the outward propagation of the transverse acoustic wave, only at the interface of the inner side of the convex ring.
  • the primary sound wave scattering effect occurs, and the convex ring acts as a transverse acoustic wave reflector.
  • the transverse acoustic wave reflector mainly reflects the transverse acoustic wave. Therefore, under the joint action of the convex ring and the longitudinal acoustic wave reflector, the transverse wave resonance is less and more Weak, the Q value of the anti-resonance point is greatly improved.
  • Fig. 1 is the three-dimensional structure schematic diagram of the resonator of the present invention
  • Fig. 2 is the partial three-dimensional structure exploded view of the resonator of the present invention
  • FIG. 3 is a cross-sectional view taken along line A-A of FIG. 1 .
  • the shape of the electrodes in the resonator is mostly apodized polygons, and the specific shape of the electrodes in the resonator can be set according to the actual design.
  • the shapes of the resonator electrodes in the embodiments shown in FIGS. 1 to 3 are all squares, and the arrangement of the shapes does not limit the shape of the resonator electrodes in this patent and cannot use apodized polygons and other shapes.
  • the resonator of the present invention is described below through specific embodiments:
  • the present invention provides a resonator 100, which includes a substrate 1, a composite film 2 disposed above the substrate 1 along a first direction, and a composite film 2 disposed on the composite film 2 close to the substrate Longitudinal acoustic wave reflector 3 on one side of 1 ; the first direction (ie, the X-axis direction) is the thickness direction of the resonator 100 .
  • the composite film 2 includes a first electrode 21 , a piezoelectric functional film 22 , a second electrode 23 and a frequency modulator 24 arranged in sequence along the first direction.
  • the first electrode 21 is disposed on the substrate 1 and the longitudinal acoustic wave reflector 3 .
  • the arrangement of two adjacent structures is not limited.
  • the composite film 2 is stacked on the surface of the substrate 1, and the first electrode 21 is stacked on the surface of the substrate 1.
  • the substrate 1 is covered on the longitudinal acoustic wave reflector 3, the piezoelectric functional film 22 is stacked on the surface of the first electrode 21, and the second electrode 23 is stacked on the piezoelectric functional film 21.
  • the functional film 22 is on the surface away from the first electrode 21; of course, in other embodiments, it is also feasible to add other film layer structures between two adjacent structures, so that the two structures are not directly stacked on each other. For example, according to the actual design needs, it is also feasible to add other film layer structures between the composite film and the substrate. In the same way, between the first electrode and the piezoelectric functional film, or between the piezoelectric functional film and the second It is also feasible to add other film layer structures between the electrodes.
  • the frequency modulator 24 includes a frequency modulation main body 241 stacked on the surface of the second electrode 23 away from the substrate 1 , and a peripheral edge of the frequency modulation main body 241 protrudes away from the substrate 1 .
  • the convex rings 242 include at least two and are spaced apart from each other, and the specific number of the convex rings 242 can be set according to the actual use situation.
  • the convex rings 242 Including two and spaced apart from each other, the arrangement of the two convex rings 242 causes the acoustic impedance of the composite membrane 2 to change "first increase, then decrease, and finally increase again", so that the The acoustic impedance of the composite film 2 where the convex ring 242 is provided is different from the acoustic impedance of the composite film 2 where the convex ring 242 is not provided.
  • the acoustic impedance of the position is discontinuous, so that the two convex rings 242 act together as the transverse acoustic wave reflector 4 .
  • the specific shape of the convex ring 242 is not limited.
  • the convex ring 242 has a closed annular structure; of course, in other embodiments, the convex ring can also be An open ring structure.
  • the area surrounded by the orthographic projection of the inner surface 2420 of the convex ring 242 to the second electrode 23 along the first direction is the resonance area 10 , and the resonator 100 is located outside the resonance area 10 .
  • the area is the non-resonant area 20; the convex ring 242 is located in the non-resonant area 20, the first electrode 21, the piezoelectric functional film 22 and the second electrode 23 all completely cover the resonant area 10, And the first electrode 21 , the piezoelectric functional film 22 and the second electrode 23 all extend at least partially into the non-resonant region 20 .
  • the acoustic impedance of the part of the resonator 100 located in the resonant region 10 is different from the acoustic impedance of the part of the resonator 100 located in the non-resonant region 20, so that the acoustic impedance of the resonant region 10 is different from that of the non-resonant region 20.
  • the acoustic impedances between the resonance regions 20 are discontinuous, and the parts of the first electrode 21 , the piezoelectric functional film 22 , the second electrode 23 and the frequency modulation main body 241 are located in the resonance region 10 .
  • the acoustic impedance is substantially unchanged; more specifically, the acoustic impedance of the portion of the composite film 2 located in the resonant region 10 is smaller than the acoustic impedance of the portion of the composite film 2 located in the non-resonant region 20 .
  • the piezoelectric functional film 22 includes a longitudinal piezoelectric film 221 and a longitudinal non-piezoelectric film 222 .
  • the vertical piezoelectric film 221 is disposed on the first electrode 21
  • the vertical non-piezoelectric film 222 is disposed around the outer periphery of the vertical piezoelectric film 221 and disposed on the first electrode 21 .
  • An electrode 21 is away from the substrate 1 side.
  • the vertical piezoelectric film 221 is located at the center of the piezoelectric functional film 22 and stacked on the first electrode 21 away from the On the surface of the substrate 1, the longitudinal non-piezoelectric film 222 is stacked on the surface of the first electrode 21 away from the substrate 1; the piezoelectric functional film 22 has a piezoelectric coefficient along the first direction , more specifically, the longitudinal piezoelectric film 221 has a piezoelectric coefficient along the first direction, and the longitudinal non-piezoelectric film 222 has a piezoelectric coefficient along the first direction of zero or less than the longitudinal pressure The piezoelectric coefficient of the electric film 221 along the first direction.
  • the longitudinal piezoelectric film 221 and the longitudinal non-piezoelectric film 222 are respectively made of two different materials; or, the longitudinal piezoelectric film 221 and the longitudinal non-piezoelectric film 222 are respectively made of two Made of the same material with different crystalline properties. Further, the longitudinal non-piezoelectric film 222 is a composite structure composed of two or more layers of films with different materials.
  • the resonance region 10 is composed of an excitation region 101 and a non-excitation region 102, wherein the longitudinal piezoelectric film 221 is located in the resonance region 10, and the excitation region 101 is formed by the composite film 2 along the A direction falling on the part of the area surrounded by the outer side surface 2210 of the longitudinal piezoelectric film 221 is formed, and the non-excited area 102 is arranged around the outer peripheral side of the excitation area 101 .
  • the non-excited area 102 is the difference between the resonance region 10 and the excitation region 101 . It should be noted that the acoustic impedance of each film layer of the composite film 2 located in the resonance region 10 is substantially constant.
  • the first electrode 21 , the piezoelectric functional film 22 , the The acoustic impedance of the second electrode 23 and the part of the frequency modulation main body 241 located in the resonance region 10 is substantially constant. Specifically, the acoustic impedance of the portion of the composite film 2 located in the excitation region 101 remains unchanged, and the acoustic impedance of the portion of the composite film 2 located in the non-excitation region 102 is within 30% of the acoustic impedance of the portion of the composite film 2 located in the excitation region 101. It can be considered that the acoustic impedance of each film layer of the composite film 2 located in the resonant region 10 is substantially constant.
  • the acoustic impedance of the longitudinal non-piezoelectric film 222 in the non-excited region 102 is equivalent to 70% to 130% of the acoustic impedance of the longitudinal piezoelectric film 221 . It can be considered that the piezoelectric functional film 22 is in the resonance region 10 .
  • the acoustic impedance of the inner part is approximately constant.
  • the acoustic impedances of the first electrode 21 , the second electrode 23 and the frequency modulation main body 241 in the excitation region 101 and the non-excitation region 102 satisfy the above relationship, it can also be considered that the first electrode 21 , the second electrode 23 and the The acoustic impedance of the portion of the frequency modulation main body portion 241 in the resonance region 10 is substantially constant.
  • the part of the composite membrane 2 located in the excitation region 101 will excite the longitudinal acoustic wave S1 (for the working mode acoustic wave) and the transverse acoustic wave S2 (for the non-working mode acoustic wave) , the longitudinal acoustic wave S1 is confined in the composite membrane 2 by the upper and lower reflection interfaces, while the transverse acoustic wave S2 propagates laterally outward from the interior of the composite membrane 2 along the first direction perpendicular to the first direction.
  • the acoustic impedance of the non-excitation area 102 is the same as that of the excitation area 101, when the transverse acoustic wave S2 passes through the interface between the excitation area 101 and the non-excitation area 102, all the Described transverse acoustic wave S2 produces sound wave scattering effect, effectively reduces the sound wave energy of transverse acoustic wave S2 The phenomenon of scattering loss occurs, it is ensured that most of the acoustic wave energy of described transverse acoustic wave S2 transmits and propagates forward;
  • the acoustic impedance of 102 is smaller than the acoustic impedance of the non-resonant region 20.
  • the transverse acoustic wave S2 passes through the interface between the non-excited region 102 and the non-resonant region 20, the transverse acoustic wave S2 is larger than that of the non-resonant region 20.
  • Part of the acoustic wave energy is mainly returned to the resonant area 10 through acoustic wave reflection and propagates, and only a small part of the energy will have the acoustic wave scattering effect, which effectively prevents most of the transverse acoustic waves S2 from entering the non-resonant area 20 to form energy loss.
  • the width of the non-excited region 102 is controlled to be small enough, the transverse incident wave and the reflected wave will not form standing wave resonance in the non-excited region 102 to avoid the formation of the parasitic mode of the transverse acoustic wave S2, The sound wave energy of the transverse sound wave S2 is further guaranteed.
  • the acoustic impedance of the part of the composite film 2 located in the resonant region 10 is discontinuous from the acoustic impedance of the part of the composite film 2 located in the non-resonant region 20, and the inner side 2420 of the convex ring 242 acts as a
  • the interface between the resonant region 10 and the non-resonant region 20 makes the acoustic impedance of the composite film 2 discontinuous on both sides of the inner side surface 2420 of the convex ring 242, and during the outward propagation of the transverse acoustic wave S2, only in the convex ring
  • a sound wave scattering effect occurs at the inner side 2420 of 242, and most of the sound wave energy of the transverse sound wave S2 is mainly returned to the resonance region 10 through sound wave reflection and propagates, effectively ensuring the sound wave energy of the transverse sound wave S2.
  • the transverse acoustic wave resonance is less and weaker, and the Q value of the anti-resonance point is greatly improved, thereby obtaining a larger device Q value.
  • the orthographic projection of the inner surface 2420 of the convex ring 242 to the longitudinal acoustic wave reflector 3 along the first direction falls within the range of the longitudinal acoustic wave reflector 3 to ensure the resonance region 10 does not exceed the range of the longitudinal acoustic wave reflector 3; in addition, in order to ensure that the excitation region 101 is located in the resonance region 10, the longitudinal piezoelectric film 221 is directed toward the frequency modulator 24 along the first direction. The orthographic projection falls completely within the resonance region 10 .
  • the specific formation method of the longitudinal acoustic wave reflector 3 is not limited, and it can be specifically set according to the actual situation.
  • the longitudinal acoustic wave reflector 3 is formed by A cavity structure is formed on the side of the substrate 1 which is close to the first electrode 21 and is recessed in a direction away from the first electrode 21 .
  • the longitudinal acoustic wave reflector is a Bragg acoustic mirror disposed on the side of the substrate close to the first electrode, and the first electrode is disposed on the side of the Bragg acoustic mirror away from the substrate, as an implementation In this way, the first electrode can be directly stacked on the longitudinal acoustic wave reflector.
  • the frequency modulator includes a frequency modulation main body part stacked on the side of the second electrode away from the substrate, and a convex ring extending from the periphery of the frequency modulation main body part to the direction away from the substrate; the convex ring
  • the area surrounded by the orthographic projection of the inner side of the resonator to the second electrode along the first direction is the resonance area, and the area where the resonator is located outside the resonance area is the non-resonant area;
  • the first electrode, the piezoelectric functional film and the second electrode are completely covered Resonance area;
  • the piezoelectric functional film includes a longitudinal piezoelectric film located in the resonance area and disposed on the side of the first electrode away from the substrate, and a longitudinal non-piezoelectric film surrounding the outer periphery of the longitudinal piezoelectric film and disposed on the side of the first electrode away from the substrate film; the acoustic impedance of the part of the
  • the side surface acts as the interface between the resonant area and the non-resonant area, so that the acoustic impedance of the composite film on both sides of the inner side of the convex ring is discontinuous, and during the outward propagation of the transverse acoustic wave, only at the interface of the inner side of the convex ring.
  • the primary sound wave scattering effect occurs, and the convex ring acts as a transverse acoustic wave reflector.
  • the transverse acoustic wave reflector mainly reflects the transverse acoustic wave. Therefore, under the joint action of the convex ring and the longitudinal acoustic wave reflector, the transverse wave resonance is less and more Weak, the Q value of the anti-resonance point is greatly improved.

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  • Acoustics & Sound (AREA)
  • Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)

Abstract

一种谐振器(100)，包括基底(1)、复合膜(2)和纵向声波反射器(3)；复合膜(2)包括沿第一方向依次设置的第一电极(21)、压电功能膜(22)、第二电极(23)和调频器(24)，第一电极(21)设置于基底(1)和纵向声波反射器(3)上方；调频器(24)包括调频主体部(241)和凸环(242)，凸环(242)的声阻抗与调频主体部(241)的声阻抗相异；凸环(242)内侧面沿第一方向向第二电极(23)的正投影所包围的区域为谐振区(10)，谐振器(100)位于谐振区(10)外的区域为非谐振区(20)；第一、第二电极(21,23)和压电功能膜(22)均完全覆盖谐振区(10)；压电功能膜(22)包括纵向压电膜(221)和纵向非压电膜(222)；谐振器(100)在谐振区(10)内和非谐振区(20)内的声阻抗相异，第一电极(21)、压电功能膜(22)、第二电极(23)和调频主体部(241)位于谐振区(10)内的部分的声阻抗均是大致不变的。所述谐振器（100）能量损失小且Q值增大。

Description

谐振器 技术领域
本发明涉及谐振器技术领域，尤其涉及一种谐振器。
 背景技术
随着智能设备的日益增多，以及物联网和5G技术的不断普及，对高性能滤波器和多功器的需求越来越大。声学谐振器作为滤波器和多功器的重要组成部分，一直是近年来研究的重点对象。
相关技术中，谐振器包括沿第一方向叠设的基底、第一电极、压电膜以及第二电极，所述基底和所述第一电极之间设置有纵向声波反射器；所述纵向声波反射器沿所述第一方向的正投影内边缘所包围的区域为谐振区，所述第二电极沿所述第一方向的投影所包围的区域为激发区，在激发区内会产生纵向声波和横向声波。
 技术问题
然而，相关技术中，横向声波向外传播到第二电极的侧边和谐振区的边缘时，各发生一次声波散射效应，导致产生大量横向波的叠加谐振，且大量声波能量进入衬底形成耗散，造成反谐振点的Q值大幅降低。
因此，实有必要提供一种新的谐振器解决上述技术问题。
 技术解决方案
本发明的目的在于提供一种减少能量损失且Q值增大的谐振器。
为了达到上述目的，本发明提供一种谐振器，其包括基底、沿第一方向设置于所述基底之上的复合膜以及设置于所述复合膜靠近所述基底一侧的纵向声波反射器；所述复合膜包括沿所述第一方向依次设置的第一电极、压电功能膜、第二电极以及调频器，所述第一电极设置于所述基底和所述纵向声波反射器之上；
所述调频器包括叠设于所述第二电极远离所述基底一侧的调频主体部以及由所述调频主体部的周缘向远离所述基底方向凸出延伸的凸环；
所述凸环的内侧面沿所述第一方向向所述第二电极的正投影所包围的区域为谐振区，所述谐振器位于所述谐振区外的区域为非谐振区；所述第一电极、所述压电功能膜和所述第二电极均完全覆盖所述谐振区；所述压电功能膜包括位于所述谐振区内且设置于所述第一电极远离所述基底一侧的纵向压电膜以及环绕所述纵向压电膜外周缘且设置于所述第一电极远离所述基底一侧的纵向非压电膜；
所述谐振器位于所述谐振区的部分的声阻抗与所述谐振器位于所述非谐振区的部分的声阻抗相异，且所述第一电极、所述压电功能膜、所述第二电极以及所述调频主体部位于所述谐振区内的部分的声阻抗均是大致不变的。
优选的，所述凸环位于所述非谐振区；所述第一电极、所述压电功能膜以及所述第二电极均至少部分延伸至所述非谐振区内。
优选的，所述凸环包括至少两个且相互间隔设置。
优选的，所述纵向声波反射器为由所述基底靠近所述第一电极一侧向远离所述第一电极的方向凹陷形成的空腔结构。
优选的，所述纵向声波反射器为设置于所述基底靠近所述第一电极一侧的布拉格声反射镜，所述第一电极设置于所述布拉格声反射镜远离所述基底一侧。
优选的，所述凸环内侧面沿所述第一方向向所述纵向声波反射器的正投影落在所述纵向声波反射器的范围内。
优选的，所述纵向压电膜沿所述第一方向向所述凸环的正投影完全落在所述谐振区内。
优选的，所述复合膜沿所述第一方向落在所述纵向压电膜的外侧面所围成的区域内的部分形成激发区，所述激发区位于所述谐振区内。
优选的，所述纵向压电膜具有沿所述第一方向的压电系数，所述纵向非压电膜沿所述第一方向的压电系数为零或小于所述纵向压电膜沿所述第一方向的压电系数。
 有益效果
与相关技术相比，本发明的谐振器中，调频器包括叠设于第二电极远离基底一侧的调频主体部以及由调频主体部的周缘向远离基底方向凸出延伸的凸环；凸环的内侧面沿第一方向向第二电极的正投影所包围的区域为谐振区，谐振器位于谐振区外的区域为非谐振区；第一电极、压电功能膜和第二电极均完全覆盖谐振区；压电功能膜包括位于谐振区内且设置于第一电极远离基底一侧的纵向压电膜以及环绕纵向压电膜外周缘且设置于第一电极远离基底一侧的纵向非压电膜；谐振器位于谐振区的部分的声阻抗与谐振器位于非谐振区的部分的声阻抗相异，且第一电极、压电功能膜、第二电极以及调频主体部位于谐振区内的部分的声阻抗均是大致不变的；上述结构中，通过凸环的设置，使得复合膜位于谐振区的部分的声阻抗与复合膜位于非谐振区的部分的声阻抗不连续，凸环的内侧面充当了谐振区和非谐振区的分界面，使得复合膜在凸环的内侧面的两侧的声阻抗不连续，而在横向声波向外传播过程中，只在凸环内侧面的界面处发生一次声波散射效应，凸环充当了横向声波反射器，横向声波反射器对横向声波主要发生的是声波反射作用，因此在凸环和纵向声波反射器的共同作用下，横向波谐振更少更弱，反谐振点的Q值大幅提高。
 附图说明
为了更清楚地说明本发明实施例中的技术方案，下面将对实施例描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其它的附图，其中：
图1为本发明谐振器的立体结构示意图；
图2为本发明谐振器的部分立体结构分解图；
图3为图1沿A-A线的剖视图。
 本发明的实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅是本发明的一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其它实施例，都属于本发明保护的范围。
首先，需要说明的是，在实际应用中，谐振器中电极的形状多为变迹多边形，而谐振器中电极具体的形状可以根据实际设计的情况进行具体的设置，比如，下面所提及到的图1-3所示的实施方式的谐振器电极的形状均为正方形，该形状的设置并非限定了本专利中的谐振器电极形状不能用变迹多边形以及其他形状。下面通过具体实施方式对本发明的谐振器进行展开描述：
请参阅图1-3所示，本发明提供一种谐振器100，其包括基底1、沿第一方向设置于所述基底1上方的复合膜2以及设置于所述复合膜2靠近所述基底1一侧的纵向声波反射器3；所述第一方向（即X轴方向）为所述谐振器100的厚度方向。
所述复合膜2包括沿所述第一方向依次设置的第一电极21、压电功能膜22、第二电极23以及调频器24。在本实施方式中，具体的，所述第一电极21设置于所述基底1和所述纵向声波反射器3之上。
相邻两个结构相互之间的设置方式是不限的，比如，在本实施方式中，所述复合膜2叠设于所述基底1的表面上，所述第一电极21叠设于所述基底1并盖设于所述纵向声波反射器3之上，所述压电功能膜22叠设于所述第一电极21的表面上，所述第二电极23叠设于所述压电功能膜22远离所述第一电极21的表面上；当然，在其他实施方式中，在相邻两个结构之间增设其它的膜层结构，使得两者相互之间不直接叠设也是可行的，譬如，可以根据实际设计的需要，复合膜与基底之间增加其它的膜层结构也是可行，同样道理，而在第一电极与压电功能膜之间、或在压电功能膜与第二电极之间增设其它的膜层结构也是可行的。
更具体的，所述调频器24包括叠设于所述第二电极23远离所述基底1的表面的调频主体部241以及由所述调频主体部241的周缘向远离所述基底1方向凸出延伸的凸环242；在此，需要说明的是，所述调频器24用于调整所述谐振器100的谐振频率，以保证所述谐振器100的谐振频率在设计该谐振器100时所预先设定的正常谐振频率范围内，避免了由于制备过程中引起的实际谐振频率偏离设计谐振器时所预先设定的正常谐振频率范围。
值得一提的是，所述凸环242包括至少两个且相互间隔设置，所述凸环242的具体数量可以根据实际使用的情况进行设置，比如，在本实施方式中，所述凸环242包括两个且相互间隔设置，此两个所述凸环242的设置引起了所述复合膜2的声阻抗发生“先增大，后减小，最后再增大”的变化，使得了所述复合膜2设置凸环242的位置的声阻抗与所述复合膜2不设置凸环242的位置的声阻抗相异，因此，所述复合膜2设置凸环242的位置和不设置凸环242的位置的声阻抗不连续，从而使得两个所述凸环242共同充当所述横向声波反射器4。当然，其他实施方式当中，凸环只设置一个也是可以行的。
还需要说明的是，所述凸环242具体的形状是不限的，在本实施方式中，所述凸环242呈封闭的环状结构；当然，在其他的实施方式中，凸环也可以呈开口的环状结构。
在此，所述凸环242的内侧面2420沿所述第一方向向所述第二电极23的正投影所包围的区域为谐振区10，所述谐振器100位于所述谐振区10外的区域为非谐振区20；所述凸环242位于所述非谐振区20，所述第一电极21、所述压电功能膜22和所述第二电极23均完全覆盖所述谐振区10，且所述第一电极21、所述压电功能膜22和所述第二电极23均至少部分延伸至所述非谐振区20内。
所述谐振器100位于所述谐振区10的部分的声阻抗与所述谐振器100位于所述非谐振区20的部分的声阻抗相异，使得所述谐振区10 的声阻抗与所述非谐振区20之间的声阻抗之间不连续，且所述第一电极21、所述压电功能膜22、所述第二电极23以及调频主体部241位于所述谐振区10内的部分的声阻抗大致不变；更具体的，所述复合膜2位于所述谐振区10的部分的声阻抗小于所述复合膜2位于所述非谐振区20的部分的声阻抗。
在实施方式中，所述压电功能薄膜22包括纵向压电膜221以及纵向非压电膜222。
在本实施方式中，所述纵向压电膜221设置于所述第一电极21之上的，所述纵向非压电膜222环绕所述纵向压电膜221外周缘设置且设置于所述第一电极21远离所述基底1一侧，具体的，本实施方式中，所述纵向压电膜221位于所述压电功能膜22的中心位置且叠设于所述第一电极21远离所述基底1的表面上，所述纵向非压电膜222叠设于所述第一电极21远离所述基底1的表面上；所述压电功能薄膜22具有沿所述第一方向的压电系数，更具体的，所述纵向压电膜221具有沿所述第一方向的压电系数，所述纵向非压电膜222沿所述第一方向的压电系数为零或小于所述纵向压电膜221沿所述第一方向的压电系数。
进一步的，所述纵向压电膜221和所述纵向非压电膜222分别为两种不同的材料制成；或，所述纵向压电膜221和所述纵向非压电膜222分别为两种结晶特性不同的同种材料制成。更进一步的，所述纵向非压电膜222为材料不同的两层或多层膜组成的复合结构。
所述谐振区10由激发区101和非激发区102共同组成，其中，所述纵向压电膜221位于所述谐振区10内，所述激发区101为由所述复合膜2沿所述第一方向落在所述纵向压电膜221的外侧面2210所围成的区域的部分形成，而所述非激发区102围绕所述激发区101外周侧设置，实际上，所述非激发区102为所述谐振区10与所述激发区101之差。值得说明的是，所述复合膜2的各个膜层位于所述谐振区10的部分的声阻抗是大致不变的，本实施方式中所述第一电极21、所述压电功能膜22、所述第二电极23和调频主体部241位于所述谐振区10内的部分的声阻抗均是大致不变的。具体的，复合膜2位于激发区101内部分的声阻抗不变，复合膜2位于非激发区102内部分的声阻抗相对于复合膜2位于激发区101内部分的声阻抗上下浮动30%以内均可以认为复合膜2的各个膜层位于谐振区10的部分的声阻抗是大致不变的。在本实施方式中，纵向非压电膜222在非激发区102内部分的声阻抗相当于纵向压电膜221的声阻抗的70%到130%均可以认为压电功能膜22在谐振区10内的部分的声阻抗是大致不变的。同样的，第一电极21、第二电极23和调频主体部241在激发区101和非激发区102内的声阻抗满足上述关系的情况下，也可以认为第一电极21、第二电极23和调频主体部241在谐振区10内的部分的声阻抗是大致不变的。
上述结构中，当谐振器100工作时，在所述复合膜2位于所述激发区101内的部分会激发纵向声波S1（为工作模态声波）和横向声波S2（为非工作模态声波），纵向声波S1被上下两个反射界面约束在所述复合膜2内，而横向声波S2则会从所述复合膜2内部沿垂直所述第一方向向外横向传播。
由于所述非激发区102的声阻抗与所述激发区101的声阻抗相同，当所述横向声波S2经过所述激发区101和所述非激发区102之间的分界面时，避免了所述横向声波S2发生声波散射效应，有效地降低横向声波S2的声波能量发生散射损耗现象，保证了所述横向声波S2的大部分声波能量发生透射并向前传播； 而又由于所述非激发区102的声阻抗小于所述非谐振区20的声阻抗，当所述横向声波S2经过所述非激发区102和所述非谐振区20之间的分界面时，但所述横向声波S2的大部分声波能量主要通过声波反射作用返回所述谐振区10内并传播，仅有小部分能量会发生声波散射效应，有效地避免了大部分的横向声波S2进入所述非谐振区20从而形成能量损耗；在实际应用中，当控制所述非激发区102的宽度足够小，横向入射波和反射波便不会在所述非激发区102形成驻波谐振，避免形成横向声波S2的寄生模态，更进一步地保证所述横向声波S2的声波能量。
上述结构中，通过凸环242的设置，使得复合膜2位于谐振区10的部分的声阻抗与复合膜2位于非谐振区20的部分的声阻抗不连续，凸环242的内侧面2420充当了谐振区10和非谐振区20的分界面，使得复合膜2在凸环242的内侧面2420的两侧的声阻抗不连续，而在横向声波S2向外传播过程中，只在所述凸环242的内侧面2420处发生一次声波散射效应，而所述横向声波S2的大部分声波能量主要通过声波反射作用返回所述谐振区10内并传播，有效地保证了所述横向声波S2的声波能量，因此在纵向声波反射器3和横向声波反射器4的配合作用下，横向声波谐振更少更弱，反谐振点的Q值大幅提高，从而获得较大的器件Q值。
需要说明的是，所述凸环242的内侧面2420沿所述第一方向向所述纵向声波反射器3的正投影落在所述纵向声波反射器3的范围内，以保证所述谐振区10不超出所述纵向声波反射器3的范围；另外，为了保证所述激发区101位于所述谐振区10内，所述纵向压电膜221沿所述第一方向向所述调频器24的正投影完全落在所述谐振区10内。
值得一提的是，所述纵向声波反射器3具体形成的方式是不限，其可以根据实际的情况进行具体的设置，比如，在本实施方式中，所述纵向声波反射器3为由所述基底1靠近所述第一电极21一侧向远离所述第一电极21的方向凹陷形成的空腔结构。
当然，在其他的实施方式中，纵向声波反射器为设置于基底靠近第一电极一侧的布拉格声反射镜也是可行，第一电极设置于该布拉格声反射镜远离基底一侧，作为一种实施方式，第一电极可以直接叠设于纵向声波反射器之上。
与相关技术相比，本发明的谐振器中，调频器包括叠设于第二电极远离基底一侧的调频主体部以及由调频主体部的周缘向远离基底方向凸出延伸的凸环；凸环的内侧面沿第一方向向第二电极的正投影所包围的区域为谐振区，谐振器位于谐振区外的区域为非谐振区；第一电极、压电功能膜和第二电极均完全覆盖谐振区；压电功能膜包括位于谐振区内且设置于第一电极远离基底一侧的纵向压电膜以及环绕纵向压电膜外周缘且设置于第一电极远离基底一侧的纵向非压电膜；谐振器位于谐振区的部分的声阻抗与谐振器位于非谐振区的部分的声阻抗相异，且第一电极、压电功能膜、第二电极以及调频主体部位于谐振区内的部分的声阻抗均是大致不变的；上述结构中，通过凸环的设置，使得复合膜位于谐振区的部分的声阻抗与复合膜位于非谐振区的部分的声阻抗不连续，凸环的内侧面充当了谐振区和非谐振区的分界面，使得复合膜在凸环的内侧面的两侧的声阻抗不连续，而在横向声波向外传播过程中，只在凸环内侧面的界面处发生一次声波散射效应，凸环充当了横向声波反射器，横向声波反射器对横向声波主要发生的是声波反射作用，因此在凸环和纵向声波反射器的共同作用下，横向波谐振更少更弱，反谐振点的Q值大幅提高。
以上所述的仅是本发明的实施方式，在此应当指出，对于本领域的普通技术人员来说，在不脱离本发明创造构思的前提下，还可以做出改进，但这些均属于本发明的保护范围。

Claims (9)

  1. 一种谐振器，其包括基底、沿第一方向设置于所述基底之上的复合膜以及设置于所述复合膜靠近所述基底一侧的纵向声波反射器，其特征在于，所述复合膜包括沿所述第一方向依次设置的第一电极、压电功能膜、第二电极以及调频器，所述第一电极设置于所述基底和所述纵向声波反射器之上；
    所述调频器包括叠设于所述第二电极远离所述基底一侧的调频主体部以及由所述调频主体部的周缘向远离所述基底方向凸出延伸的凸环；
    所述凸环的内侧面沿所述第一方向向所述第二电极的正投影所包围的区域为谐振区，所述谐振器位于所述谐振区外的区域为非谐振区；所述第一电极、所述压电功能膜和所述第二电极均完全覆盖所述谐振区；所述压电功能膜包括位于所述谐振区内且设置于所述第一电极远离所述基底一侧的纵向压电膜以及环绕所述纵向压电膜外周缘且设置于所述第一电极远离所述基底一侧的纵向非压电膜；
    所述谐振器位于所述谐振区的部分的声阻抗与所述谐振器位于所述非谐振区的部分的声阻抗相异，且所述第一电极、所述压电功能膜、所述第二电极以及所述调频主体部位于所述谐振区内的部分的声阻抗均是大致不变的。
  2. 根据权利要求1所述的谐振器，其特征在于，所述凸环位于所述非谐振区；所述第一电极、所述压电功能膜以及所述第二电极均至少部分延伸至所述非谐振区内。
  3. 根据权利要求2所述的谐振器，其特征在于，所述凸环包括至少两个且相互间隔设置。
  4. 根据权利要求1所述的谐振器，其特征在于，所述纵向声波反射器为由所述基底靠近所述第一电极一侧向远离所述第一电极的方向凹陷形成的空腔结构。
  5. 根据权利要求1所述的谐振器，其特征在于，所述纵向声波反射器为设置于所述基底靠近所述第一电极一侧的布拉格声反射镜，所述第一电极设置于所述布拉格声反射镜远离所述基底一侧。
  6. 根据权利要求4或5所述的谐振器，其特征在于，所述凸环内侧面沿所述第一方向向所述纵向声波反射器的正投影落在所述纵向声波反射器的范围内。
  7. 根据权利要求1所述的谐振器，其特征在于，所述纵向压电膜沿所述第一方向向所述凸环的正投影完全落在所述谐振区内。
  8. 根据权利要求1所述的谐振器，其特征在于，所述复合膜沿所述第一方向落在所述纵向压电膜的外侧面所围成的区域内的部分形成激发区，所述激发区位于所述谐振区内。
  9. 根据权利要求1所述的谐振器，其特征在于，所述纵向压电膜具有沿所述第一方向的压电系数，所述纵向非压电膜沿所述第一方向的压电系数为零或小于所述纵向压电膜沿所述第一方向的压电系数。
PCT/CN2020/122195 2020-07-10 2020-10-20 谐振器 WO2022007234A1 (zh)

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Publication number Priority date Publication date Assignee Title
CN101924529A (zh) * 2010-08-31 2010-12-22 庞慰 压电谐振器结构
US20140354115A1 (en) * 2011-09-14 2014-12-04 Avago Technologies General Ip (Singapore) Pte. Ltd. Solidly mounted acoustic resonator having multiple lateral features
CN107592090A (zh) * 2016-07-07 2018-01-16 三星电机株式会社 声波谐振器及其制造方法
CN108233889A (zh) * 2018-01-31 2018-06-29 湖北宙讯科技有限公司 谐振器

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101924529A (zh) * 2010-08-31 2010-12-22 庞慰 压电谐振器结构
US20140354115A1 (en) * 2011-09-14 2014-12-04 Avago Technologies General Ip (Singapore) Pte. Ltd. Solidly mounted acoustic resonator having multiple lateral features
CN107592090A (zh) * 2016-07-07 2018-01-16 三星电机株式会社 声波谐振器及其制造方法
CN108233889A (zh) * 2018-01-31 2018-06-29 湖北宙讯科技有限公司 谐振器

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