CN113810006A

CN113810006A - Bulk acoustic wave resonance device, filtering device and radio frequency front end device

Info

Publication number: CN113810006A
Application number: CN202111053511.6A
Authority: CN
Inventors: 韩兴; 周建
Original assignee: Changzhou Chengxin Semiconductor Co Ltd
Current assignee: Changzhou Chengxin Semiconductor Co Ltd
Priority date: 2021-09-08
Filing date: 2021-09-08
Publication date: 2021-12-17
Also published as: WO2023036025A1

Abstract

The embodiment of the invention provides a bulk acoustic wave resonance device, a filtering device and a radio frequency front end device, wherein the bulk acoustic wave resonance device comprises: a first layer comprising a cavity; at least one end of the first electrode layer is positioned in the cavity; the piezoelectric layer is positioned on the first electrode layer and covers the cavity, the piezoelectric layer comprises a first side and a second side opposite to the first side, and the first electrode layer is positioned on the first side; a second electrode layer on the second side on the piezoelectric layer; and at least one side cavity between the first layer and the piezoelectric layer, embedded in the first layer, and communicating with the cavity, the at least one side cavity having a depth less than the depth of the cavity. And a shallow side cavity is arranged beside at least one side of the cavity, and transverse sound waves are reflected at the junction of the piezoelectric layer or the electrode layer or the edge structure and the side cavity, so that leakage waves propagating towards a supporting layer (such as a substrate and an intermediate layer) in a transverse mode are blocked, and the Q value is improved.

Description

Bulk acoustic wave resonance device, filtering device and radio frequency front end device

Technical Field

The invention relates to the technical field of semiconductors, in particular to a bulk acoustic wave resonance device, a filtering device and a radio frequency front-end device.

Background

A Radio Frequency (RF) front-end chip of a wireless communication device includes a power amplifier, an antenna switch, a Radio Frequency filter, a multiplexer, a low noise amplifier, and the like. The rf filter includes a piezoelectric Acoustic Surface Wave (SAW) filter, a Bulk Acoustic Wave (BAW) filter, a Micro-Electro-Mechanical System (MEMS) filter, an Integrated Passive Devices (IPD) filter, and the like.

The BAW resonator has a high quality factor value (Q value), and is made into a low insertion loss and high out-of-band rejection radio frequency filter, i.e., a BAW filter, which is a mainstream radio frequency filter used in wireless communication devices such as mobile phones and base stations at present. Where the Q value is the quality factor value of the resonator, defined as the center frequency divided by the 3dB bandwidth of the resonator. The higher the Q value, the better the performance of the resonator and the better the performance of the manufactured filter. BAW resonators convert mechanical energy into electrical energy or electrical energy into mechanical energy during vibration, which represents the degree of mutual energy conversion using an electro-mechanical coupling factor (i.e., electro-mechanical coupling factor)

)。

Wherein f is_sIs the resonant frequency, f_pFor anti-resonant frequency, when the resonator is

The larger the bandwidth of the filter the resonator can make. The BAW filter is typically used at a frequency of 0.7GHz to 7 GHz.

As wireless communication technology evolves, more and more frequency bands are used, and meanwhile, with the application of frequency band overlapping use technology such as carrier aggregation, mutual interference among wireless frequency bands becomes more and more serious. The high-performance BAW technology can solve the problem of mutual interference between frequency bands. With the coming of the 5G era, a wireless mobile network introduces a higher communication frequency band and a wider frequency band, and currently, only the BAW technology can solve the problem of filtering in a high frequency band and a high bandwidth.

The BAW filter consists of a BAW resonator, wherein the BAW resonator converts an electric signal into an acoustic signal through a metal-piezoelectric film-metal transducer, and then converts the acoustic signal back into the electric signal through the metal-piezoelectric film-metal transducer. BAW filters filter signals in the acoustic signal interval, and since the acoustic signal velocity is about one hundred thousand times the electrical signal velocity at the same frequency, the BAW filter of the same frequency is much smaller in size than the electrical rf filter. Since the metal-piezoelectric thin film-metal transducer is the most important component of the BAW resonator, whether the acoustic structure of the BAW resonator can effectively limit the energy leakage of the leakage wave directly determines the electromechanical coupling coefficient and the Q value of the BAW resonator. The 5G mobile communication technology puts higher requirements on the passband bandwidth, the insertion loss and the out-of-band rejection of the BAW filter, and the three indexes are related to the electromechanical coupling coefficient and the Q value of the BAW resonator, so the acoustic structure of the BAW resonator needs to be further optimized and improved.

Fig. 1 shows a BAW filter circuit 100 comprising a ladder circuit consisting of a plurality of BAW resonators, wherein f1, f2, f3, f4 represent 4 different frequencies, respectively. In each BAW resonator, metal electrodes on both sides of a piezoelectric layer of the resonator generate alternating positive and negative voltages, and the piezoelectric layer generates an acoustic wave by the alternating positive and negative voltages, and the acoustic wave in the resonator propagates in a direction perpendicular to the piezoelectric layer. In order to form resonance, the acoustic wave needs to generate total reflection on the upper surface of the upper metal electrode and the lower surface of the lower metal electrode to form a standing acoustic wave. The condition for the reflection of the acoustic wave is that the acoustic impedance of the contact area with the upper surface of the upper metal electrode and the lower surface of the lower metal electrode is greatly different from the acoustic impedance of the metal electrode.

A Film Bulk Acoustic wave Resonator (FBAR) is a BAW Resonator that confines Acoustic energy within the device, with air or vacuum above the resonant region and a cavity below. The acoustic impedance of air and vacuum is greatly different from that of the metal electrode, and the sound wave can be totally reflected on the upper surface of the upper metal electrode and the lower surface of the lower metal electrode to form standing waves.

Fig. 2 shows a schematic structure of a cross section a of an FBAR 200. The FBAR 200 includes: a substrate 201, the upper surface side of the substrate 201 comprising a cavity 203; an electrode layer 205 on the substrate 201 and the cavity 203; a piezoelectric layer 207 on the substrate 201 and covering the electrode layer 205, wherein the piezoelectric layer 207 comprises a convex portion 207a and is positioned above the electrode layer 205; an electrode layer 209 located on the piezoelectric layer 207, the electrode layer 209 comprising a protrusion 209a located on the protrusion 207 a; wherein a resonance region 211 (i.e. the coinciding area of the electrode layer 205 and the protrusion 209 a) is located on the cavity 203, having a coinciding contact with the substrate 201. If the acoustic impedance of the substrate 201 is similar to that of the piezoelectric layer 207, the transverse acoustic wave generated by the resonant region 211 will diffuse toward the non-resonant region in the direction of the arrow, and propagate into the substrate 201, thereby decreasing the Q value of the resonator.

Disclosure of Invention

The problem to be solved by the present invention is to provide a bulk acoustic wave resonator device that can block a leakage wave propagating in a transverse mode toward a support layer (e.g., substrate, intermediate layer) to improve a Q value.

To solve the above problems, an embodiment of the present invention provides a bulk acoustic wave resonator device, including a first layer including a cavity; a first electrode layer, at least one end of the first electrode layer being located within the cavity; the piezoelectric layer is positioned on the first electrode layer along the vertical direction and covers the cavity, the piezoelectric layer comprises a first side and a second side opposite to the first side along the vertical direction, the first electrode layer is positioned on the first side, and the overlapped area of the first electrode layer, the second electrode layer and the piezoelectric layer is a first area; a second electrode layer on the second side and on the piezoelectric layer along the vertical direction; and at least one side cavity, located between the first layer and the piezoelectric layer, embedded in the first layer, and communicated with the cavity, wherein the depth of the at least one side cavity is smaller than that of the cavity, and the at least one side cavity is located outside the first area along the horizontal direction.

It should be noted that, a shallow side cavity is disposed outside the resonant region beside at least one side of the cavity, the acoustic impedance of the vacuum or air in the side cavity is not matched with (i.e., different from) the acoustic impedance of the piezoelectric layer or the electrode layer or the edge structure, and the transverse acoustic wave is reflected at the interface between the piezoelectric layer or the electrode layer or the edge structure and the side cavity, so as to block the leakage wave propagating towards the support layer (e.g., the substrate, the intermediate layer) in the transverse mode, and improve the Q value.

In some embodiments, the at least one side cavity comprises: and a first side cavity located outside the first region in the horizontal direction, contacting the piezoelectric layer, and having an overlapping portion with the second electrode layer.

In some embodiments, the at least one side cavity comprises: and a second side cavity located outside the first region in the horizontal direction, located between the first layer and the first electrode layer, contacting the first electrode layer, and having an overlapping portion with the first electrode layer.

In some embodiments, the bulk acoustic wave resonator device further comprises: and at least one edge structure located at an edge of an overlapping portion of the first electrode layer and the second electrode layer.

In some embodiments, the at least one edge structure comprises: and the first edge structure is positioned on the second side and positioned on the second electrode layer, wherein the first edge structure comprises a first peripheral part, and the first peripheral part is positioned on the edge of the second electrode layer, which is overlapped with the first electrode layer.

In some embodiments, the first peripheral portion is annular.

In some embodiments, the material of the first edge structure comprises a metal.

In some embodiments, the at least one edge structure comprises: and the first electrode layer is positioned on the second edge structure, the second edge structure comprises a second peripheral part, and the second peripheral part is positioned in the cavity and positioned on the edge of the superposition part of the first electrode layer and the second electrode layer.

In some embodiments, the second peripheral portion is annular.

In some embodiments, the material of the second edge structure comprises a metal.

In some embodiments, the at least one side cavity comprises: and the third side cavity is positioned outside the first area along the horizontal direction, positioned between the first layer and the second edge structure, contacts the second edge structure and has an overlapped part with the second edge structure.

In some embodiments, the at least one edge structure comprises: and the third edge structure is positioned on the second side and on the second electrode layer, wherein the third edge structure comprises a third surrounding part, and the third surrounding part is positioned on the second electrode layer and on the partial edge of the first electrode layer superposition part.

In some embodiments, the at least one edge structure further comprises: and the first electrode layer is positioned on the fourth edge structure, the fourth edge structure comprises a fourth surrounding part, and the fourth surrounding part is positioned in the cavity and positioned on the first electrode layer and the partial edge of the superposition part of the second electrode layer.

In some embodiments, the third and fourth peripheral portions partially overlap to form an annular peripheral edge.

In some embodiments, the material of the third edge structure comprises a metal and the material of the fourth edge structure comprises a metal.

In some embodiments, the at least one side cavity comprises: and the fourth side cavity is positioned outside the first area along the horizontal direction, positioned between the first layer and the fourth edge structure, contacted with the fourth edge structure and provided with an overlapped part with the fourth edge structure.

In some embodiments, the at least one edge structure comprises: and a fifth edge structure located on the second side and on the piezoelectric layer, wherein the fifth edge structure includes a fifth peripheral portion, the second electrode layer is located inside the fifth peripheral portion, the fifth peripheral portion is overlapped with the first electrode layer, and an overlapped portion of the second electrode layer and the first electrode layer is the second electrode layer.

In some embodiments, the fifth peripheral portion is annular.

In some embodiments, the material of the fifth edge structure comprises a metal.

In some embodiments, the at least one side cavity comprises: a fifth side cavity outside the first area along the horizontal direction, contacting the piezoelectric layer, having an overlap with the fifth edge structure.

In some embodiments, the at least one edge structure includes a sixth edge structure located on the first side, the piezoelectric layer is further located on the sixth edge structure, the sixth edge structure includes a sixth peripheral portion located in the cavity, the first electrode layer is located inside the sixth peripheral portion, and the sixth peripheral portion coincides with the second electrode layer, where a coinciding portion of the first electrode layer with the second electrode layer is the first electrode layer.

In some embodiments, the sixth peripheral portion is annular.

In some embodiments, the material of the sixth edge structure comprises a metal.

In some embodiments, the at least one side cavity comprises: and the sixth side cavity is positioned outside the first area along the horizontal direction, positioned between the first layer and the sixth edge structure, contacted with the sixth edge structure and provided with an overlapped part with the sixth edge structure.

In some embodiments, the at least one edge structure comprises a seventh edge structure on the second side on the piezoelectric layer, the seventh edge structure comprising a seventh peripheral portion at a partial edge of the second electrode layer coinciding with the first electrode layer.

In some embodiments, the at least one side cavity comprises: a seventh side cavity outside the first region in the horizontal direction, contacting the piezoelectric layer, and having an overlap with the seventh edge structure.

In some embodiments, the at least one edge structure further comprises an eighth edge structure located on the first side, the piezoelectric layer further located on the eighth edge structure, the eighth edge structure comprising an eighth peripheral portion located within the cavity at a partial edge of the first electrode layer that coincides with the second electrode layer.

In some embodiments, the eighth and seventh peripheral portions partially coincide to form an annular peripheral edge.

In some embodiments, the material of the seventh edge structure comprises a metal and the material of the eighth edge structure comprises a metal.

In some embodiments, the at least one side cavity comprises: and the eighth side cavity is positioned outside the first area along the horizontal direction, positioned between the first layer and the eighth edge structure, contacted with the eighth edge structure, and provided with a superposition part with the eighth edge structure.

In some embodiments, the first layer comprises: an intermediate layer comprising the cavity, wherein the material of the intermediate layer includes, but is not limited to, at least one of: polymer, insulating dielectric, polysilicon.

In some embodiments, the at least one side cavity is located between the intermediate layer and the piezoelectric layer, embedding the intermediate layer.

The embodiment of the present invention further provides a filtering apparatus, including but not limited to: at least one of the above embodiments provides a bulk acoustic wave resonator device.

The embodiment of the present invention further provides a radio frequency front end device, including but not limited to: the power amplifying device and at least one filtering device provided by the above embodiment; the power amplifying device is connected with the filtering device.

The embodiment of the present invention further provides a radio frequency front end device, including but not limited to: the low noise amplifying device and at least one filtering device provided by the above embodiment; the low-noise amplifying device is connected with the filtering device.

The embodiment of the present invention further provides a radio frequency front end device, including but not limited to: the multiplexing device comprises at least one filtering device provided by the above embodiment.

Drawings

Fig. 1 is a schematic diagram of a BAW filter circuit 100;

FIG. 2 is a schematic diagram of a cross-section A of an FBAR 200;

FIG. 3a is a schematic structural diagram of a bulk acoustic wave resonator 300 according to an embodiment of the present invention;

FIG. 3b is a schematic diagram of a structure of a hexagonal crystal grain;

FIG. 3c (i) is a schematic diagram of the structure of an orthorhombic crystal grain;

FIG. 3c (ii) is a schematic structural diagram of a tetragonal crystal grain;

FIG. 3c (iii) is a schematic structural diagram of a cubic crystal grain;

FIG. 3d is a schematic diagram of the performance of a bulk acoustic wave resonator device 300 according to an embodiment of the present invention;

fig. 3e is a schematic top view of a bulk acoustic wave resonator device 300 according to an embodiment of the present invention;

FIG. 4a is a schematic structural diagram of a bulk acoustic wave resonator device 400 according to an embodiment of the present invention;

fig. 4b is a schematic top view of a bulk acoustic wave resonator device 400 according to an embodiment of the present invention;

fig. 5a is a schematic structural diagram of a section a of a bulk acoustic wave resonator 500 according to an embodiment of the present invention;

fig. 5b is a schematic top view of a bulk acoustic wave resonator device 500 according to an embodiment of the present invention;

fig. 6a is a schematic structural diagram of a section a of a bulk acoustic wave resonator 600 according to an embodiment of the present invention;

fig. 6b is a schematic top view of a bulk acoustic wave resonator device 600 according to an embodiment of the present invention;

fig. 6c is a schematic structural diagram of a bulk acoustic wave resonator 600 according to an embodiment of the present invention in cross section B;

fig. 7a is a schematic structural diagram of a section a of a bulk acoustic wave resonator device 700 according to an embodiment of the present invention;

fig. 7b is a schematic top view of a bulk acoustic wave resonator device 700 according to an embodiment of the present invention;

fig. 8 is a schematic structural diagram of a bulk acoustic wave resonator 800 according to an embodiment of the present invention;

fig. 9 is a schematic structural diagram of a bulk acoustic wave resonator 900 according to an embodiment of the present invention in a cross section a;

fig. 10a is a schematic structural diagram of a section a of a bulk acoustic wave resonator 1000 according to an embodiment of the present invention;

fig. 10b is a schematic top view of a bulk acoustic wave resonator device 1000 according to an embodiment of the present invention;

fig. 10c is a schematic structural diagram of a section B of the bulk acoustic wave resonator 1000 according to the embodiment of the present invention;

fig. 11 is a schematic structural diagram of a section a of a bulk acoustic wave resonator device 1100 according to an embodiment of the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described herein, and thus the present invention is not limited to the specific embodiments disclosed below.

As described in the background section, if the acoustic impedance of the substrate and the acoustic impedance of the piezoelectric layer are similar, the transverse acoustic wave generated in the resonant region will spread out in the non-resonant region in the direction of the arrow and propagate into the substrate, thereby causing the Q value of the resonator to decrease.

The inventor of the present invention found that by providing a shallow side cavity outside the resonance region beside at least one side of the cavity, the acoustic impedance of the vacuum or air in the side cavity is not matched with (i.e. different from) the acoustic impedance of the piezoelectric layer or the electrode layer or the edge structure, and the transverse acoustic wave is reflected at the interface of the piezoelectric layer or the electrode layer or the edge structure and the side cavity, so that the leakage wave propagating towards the support layer (e.g. the substrate, the intermediate layer) in the transverse mode is blocked, and the Q value is improved.

An embodiment of the present invention provides a bulk acoustic wave resonance device, including: a first layer comprising a cavity; a first electrode layer, at least one end of the first electrode layer being located within the cavity; the piezoelectric layer is positioned on the first electrode layer along the vertical direction and covers the cavity, the piezoelectric layer comprises a first side and a second side opposite to the first side along the vertical direction, and the first electrode layer is positioned on the first side; the second electrode layer is positioned on the second side along the vertical direction and positioned on the piezoelectric layer, and the overlapped area of the first electrode layer, the second electrode layer and the piezoelectric layer is a first area; and at least one side cavity, located between the first layer and the piezoelectric layer, embedded in the first layer, and communicated with the cavity, wherein the depth of the at least one side cavity is smaller than that of the cavity, and the at least one side cavity is located outside the first area along the horizontal direction (i.e., has no overlapping part with the first area).

It should be noted that, besides at least one side of the cavity, outside the resonant region, a shallow side cavity is provided, the acoustic impedance of the vacuum or air in the side cavity is not matched with (i.e., different from) the acoustic impedance of the piezoelectric layer or the electrode layer or the edge structure, and the transverse acoustic wave is reflected at the interface between the piezoelectric layer or the electrode layer or the edge structure and the side cavity, so as to block the leakage wave propagating towards the support layer (e.g., the substrate, the intermediate layer) in the transverse mode, and improve the Q value.

In some embodiments, the at least one edge structure comprises: and the first edge structure is positioned on the second side and positioned on the second electrode layer, wherein the first edge structure comprises a first peripheral part, and the first peripheral part is positioned on the edge of the second electrode layer, which is overlapped with the first electrode layer. In some embodiments, the first peripheral portion is annular. In some embodiments, the material of the first edge structure comprises a metal.

In some embodiments, the at least one edge structure comprises: and the first electrode layer is positioned on the second edge structure, the second edge structure comprises a second peripheral part, and the second peripheral part is positioned in the cavity and positioned on the edge of the superposition part of the first electrode layer and the second electrode layer. In some embodiments, the second peripheral portion is annular. In some embodiments, the material of the second edge structure comprises a metal. In some embodiments, the at least one side cavity comprises: and the third side cavity is positioned outside the first area along the horizontal direction, positioned between the first layer and the second edge structure, contacts the second edge structure and has an overlapped part with the second edge structure.

In some embodiments, the at least one edge structure comprises: and the third edge structure is positioned on the second side and on the second electrode layer, wherein the third edge structure comprises a third surrounding part, and the third surrounding part is positioned on the second electrode layer and on the partial edge of the first electrode layer superposition part. In some embodiments, the at least one edge structure further comprises: and the first electrode layer is positioned on the fourth edge structure, the fourth edge structure comprises a fourth surrounding part, and the fourth surrounding part is positioned in the cavity and positioned on the first electrode layer and the partial edge of the superposition part of the second electrode layer. In some embodiments, the third and fourth peripheral portions partially overlap to form an annular peripheral edge. In some embodiments, the material of the third edge structure comprises a metal and the material of the fourth edge structure comprises a metal. In some embodiments, the at least one side cavity comprises: and the fourth side cavity is positioned outside the first area along the horizontal direction, positioned between the first layer and the fourth edge structure, contacted with the fourth edge structure and provided with an overlapped part with the fourth edge structure.

In some embodiments, the at least one edge structure comprises: and a fifth edge structure located on the second side and on the piezoelectric layer, wherein the fifth edge structure includes a fifth peripheral portion, the second electrode layer is located inside the fifth peripheral portion, the fifth peripheral portion is overlapped with the first electrode layer, and an overlapped portion of the second electrode layer and the first electrode layer is the second electrode layer. In some embodiments, the fifth peripheral portion is annular. In some embodiments, the material of the fifth edge structure comprises a metal. In some embodiments, the at least one side cavity comprises: a fifth side cavity outside the first area along the horizontal direction, contacting the piezoelectric layer, having an overlap with the fifth edge structure.

In some embodiments, the at least one edge structure includes a sixth edge structure located on the first side, the piezoelectric layer is further located on the sixth edge structure, the sixth edge structure includes a sixth peripheral portion located in the cavity, the first electrode layer is located inside the sixth peripheral portion, and the sixth peripheral portion coincides with the second electrode layer, where a coinciding portion of the first electrode layer with the second electrode layer is the first electrode layer. In some embodiments, the sixth peripheral portion is annular. In some embodiments, the material of the sixth edge structure comprises a metal. In some embodiments, the at least one side cavity comprises: and the sixth side cavity is positioned outside the first area along the horizontal direction, positioned between the first layer and the sixth edge structure, contacted with the sixth edge structure and provided with an overlapped part with the sixth edge structure.

In some embodiments, the at least one edge structure comprises a seventh edge structure on the second side on the piezoelectric layer, the seventh edge structure comprising a seventh peripheral portion at a partial edge of the second electrode layer coinciding with the first electrode layer. In some embodiments, the at least one side cavity comprises: a seventh side cavity outside the first region in the horizontal direction, contacting the piezoelectric layer, and having an overlap with the seventh edge structure. In some embodiments, the at least one edge structure further comprises an eighth edge structure located on the first side, the piezoelectric layer further located on the eighth edge structure, the eighth edge structure comprising an eighth peripheral portion located within the cavity at a partial edge of the first electrode layer that coincides with the second electrode layer. In some embodiments, the eighth and seventh peripheral portions partially coincide to form an annular peripheral edge. In some embodiments, the material of the seventh edge structure comprises a metal and the material of the eighth edge structure comprises a metal. In some embodiments, the at least one side cavity comprises: and the eighth side cavity is positioned outside the first area along the horizontal direction, positioned between the first layer and the eighth edge structure, contacted with the eighth edge structure, and provided with a superposition part with the eighth edge structure.

In some embodiments, the first layer comprises: an intermediate layer comprising the cavity, wherein the material of the intermediate layer includes, but is not limited to, at least one of: polymer, insulating dielectric, polysilicon. In some embodiments, the at least one side cavity is located between the intermediate layer and the piezoelectric layer, embedding the intermediate layer.

Fig. 3 to 11 show embodiments of the invention using resonant devices of different structures, but the invention can also be implemented in other ways than those described herein, and therefore the invention is not limited to the embodiments disclosed below.

Fig. 3a is a schematic structural diagram of a section a of a bulk acoustic wave resonator 300 according to an embodiment of the present invention.

As shown in fig. 3a, an embodiment of the present invention provides a bulk acoustic wave resonator device 300 including: a substrate 301; the middle layer 302 is positioned on the substrate 301, the upper surface side of the middle layer 302 comprises a cavity 303 and a groove 304, wherein the groove 304 is positioned on one side of the cavity 303 and is communicated with the cavity 303, and the depth of the groove 304 is smaller than that of the cavity 303; an electrode layer 305, a first end 305a of the electrode layer 305 is located in the cavity 303, and a second end 305b of the electrode layer 305 is located in the groove 304, wherein the depth of the groove 304 is equal to the thickness of the electrode layer 305; a piezoelectric layer 306 disposed on the electrode layer 305 and the intermediate layer 302, covering the cavity 303, wherein the piezoelectric layer 306 includes a first side 306a and a second side 306b opposite to the first side 306a, and the electrode layer 305 and the intermediate layer 302 are disposed on the first side 306 a; an electrode layer 307 on the second side 306b on the piezoelectric layer 306; a side cavity 308, located at said first side 306a, located between said intermediate layer 302 and said piezoelectric layer 306, embedded in said intermediate layer 302, and communicating with said cavity 303, said side cavity 308 contacting said piezoelectric layer 306; and a side cavity 309, located between said intermediate layer 302 and said electrode layer 305, embedded in said intermediate layer 302, communicating with said cavity 303; wherein the depth of the side cavity 308 is less than the depth of the cavity 303, and the depth of the side cavity 309 is less than the depth of the cavity 303.

In this embodiment, the overlapping region of the electrode layer 305, the piezoelectric layer 306, and the electrode layer 307 is a resonance region, and the side cavity 308 and the side cavity 309 are located outside the resonance region in the horizontal direction.

In this embodiment, the material of the substrate 301 includes, but is not limited to, at least one of the following: silicon, silicon carbide, glass, gallium arsenide, gallium nitride, ceramics.

In this embodiment, the material of the intermediate layer 302 includes, but is not limited to, at least one of the following: polymer, insulating dielectric, polysilicon. In this embodiment, the polymer includes, but is not limited to, at least one of: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide. In this embodiment, the insulating dielectric includes, but is not limited to, at least one of: aluminum nitride, silicon dioxide, silicon nitride, titanium oxide.

In this embodiment, the material of the electrode layer 305 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium.

In this embodiment, the piezoelectric layer 306 is a flat layer and also covers the upper surface side of the intermediate layer 302. In this embodiment, the material of the piezoelectric layer 306 includes, but is not limited to, at least one of the following: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

In this embodiment, the piezoelectric layer 306 includes a plurality of grains including a first grain and a second grain, wherein the first grain and the second grain are any two grains of the plurality of grains. Those skilled in the art know that the crystal orientation, crystal plane, etc. of the crystal grain can be expressed based on a coordinate system. As shown in fig. 3b, the hexagonal crystal grains, for example, aluminum nitride crystal grains, are represented by an ac three-dimensional coordinate system (including a-axis and c-axis). As shown in fig. 3c, crystal grains of (i) orthorhombic system (a ≠ b ≠ c), (ii) tetragonal system (a ≠ c), and (iii) cubic system (a ═ b ≠ c) are represented by xyz stereo coordinate system (including x-axis, y-axis, and z-axis). In addition to the above two examples, the die may also be represented based on other coordinate systems known to those skilled in the art, and thus the present invention is not limited by the above two examples.

In this embodiment, the first die may be represented based on a first stereo coordinate system, and the second die may be represented based on a second stereo coordinate system, where the first stereo coordinate system at least includes a first coordinate axis along a first direction and a third coordinate axis along a third direction, and the second stereo coordinate system at least includes a second coordinate axis along a second direction and a fourth coordinate axis along a fourth direction, where the first coordinate axis corresponds to a height of the first die, and the second coordinate axis corresponds to a height of the second die.

In this embodiment, the first direction and the second direction are the same or opposite. It should be noted that the first direction and the second direction are the same: the included angle range of the vector along the first direction and the vector along the second direction comprises 0 degree to 5 degrees; the first direction and the second direction are opposite to each other: an included angle range of a vector along the first direction and a vector along the second direction includes 175 degrees to 180 degrees.

In another embodiment, the first stereo coordinate system is an ac stereo coordinate system, wherein the first coordinate axis is a first c-axis, and the third coordinate axis is a first a-axis; the second three-dimensional coordinate system is an ac three-dimensional coordinate system, the second coordinate axis is a second c-axis, the fourth coordinate axis is a second a-axis, and the first c-axis and the second c-axis are directed in the same direction or in opposite directions.

In another embodiment, the first stereoscopic coordinate system further comprises a fifth coordinate axis along a fifth direction, and the second stereoscopic coordinate system further comprises a sixth coordinate axis along a sixth direction. In another embodiment, the first direction and the second direction are the same or opposite, and the third direction and the fourth direction are the same or opposite. It should be noted that the third direction and the fourth direction are the same: the included angle range of the vector along the third direction and the vector along the fourth direction comprises 0 degree to 5 degrees; the third direction and the fourth direction are opposite to each other: an included angle range of a vector along the third direction and a vector along the fourth direction includes 175 degrees to 180 degrees.

In another embodiment, the first stereo coordinate system is an xyz stereo coordinate system, wherein the first coordinate axis is a first z-axis, the third coordinate axis is a first y-axis, and the fifth coordinate axis is a first x-axis; the second three-dimensional coordinate system is an xyz three-dimensional coordinate system, the second coordinate axis is a second z axis, the fourth coordinate axis is a second y axis, and the sixth coordinate axis is a second x axis. In another embodiment, the first and second z-axes are pointing in the same direction, and the first and second y-axes are pointing in the same direction. In another embodiment, the first and second z-axes are oppositely directed and the first and second y-axes are oppositely directed. In another embodiment, the first and second z-axes are pointing in the same direction, and the first and second y-axes are pointing in opposite directions. In another embodiment, the first and second z-axes are oppositely directed, and the first and second y-axes are identically directed.

In this embodiment, the piezoelectric layer 306 includes a plurality of grains, and the half width of the rocking curve of the crystal formed by the plurality of grains is less than 2.5 degrees. It should be noted that a Rocking curve (Rocking curve) describes the angular divergence size of a specific crystal plane (a crystal plane determined by a diffraction angle) in a sample, and is represented by a planar coordinate system, wherein an abscissa is an included angle between the crystal plane and the sample plane, an ordinate represents the diffraction intensity of the crystal plane at a certain included angle, the Rocking curve is used for representing the crystal quality, and the smaller the half-peak width angle is, the better the crystal quality is. Further, the Full Width at Half Maximum (FWHM) refers to the distance between two points in one peak of the function, the front and rear function values of which are equal to Half of the peak value.

It should be noted that forming the piezoelectric layer 306 on a plane can make the piezoelectric layer 306 not include a crystal grain with obvious turning, so that the electromechanical coupling coefficient of the resonance device and the Q value of the resonance device can be improved.

In this embodiment, the material of the electrode layer 307 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium.

In this embodiment, a portion of the electrode layer 305 overlapping with the electrode layer 307 is located in the cavity 303; the portion of the electrode 307 coinciding with the electrode 305 is located above the cavity 303.

In this embodiment, the cavity 303 is located inside the side cavity 308 (i.e. the side pointing towards the central axis of the filter device 300), and the cavity 303 is also located inside the side cavity 309. In this embodiment, the electrode layer 307 is located above the side cavity 308, and has an overlapping portion with the side cavity 308; the electrode layer 305 is located on the side cavity 309, and has an overlapping portion with the side cavity 309.

It should be noted that the acoustic impedance of the vacuum state or air in the side cavity 308 is smaller than the acoustic impedance of the piezoelectric layer 306, the acoustic impedance of the vacuum state or air in the side cavity 309 is smaller than the acoustic impedance of the electrode layer 305, and the acoustic wave of the transverse mode is reflected at the boundary between the side cavity 308 and the piezoelectric layer 306 and the boundary between the side cavity 309 and the electrode layer 305, so that the leakage wave propagating towards the intermediate layer 302 in the transverse mode is blocked, and the Q value is increased. To more intuitively understand this beneficial effect, please refer to fig. 3d, a figure of merit curve 310 represents the normalized Q value of a BAW resonator device without a side cavity, and a figure of merit curve 311 represents the normalized Q value of a BAW resonator device including a side cavity (e.g., the side cavity 308 or the side cavity 309). It should be noted that fig. 3d is only schematic for more intuitively understanding the beneficial effects of the embodiment of the present invention, but is not equivalent to the actual performance of the BAW resonance device of the embodiment of the present invention.

Fig. 3e is a schematic top view of the bulk acoustic wave resonator device 300 according to the embodiment of the present invention.

As shown in fig. 3e, in the present embodiment, the cavity 303 has an octagonal shape corresponding to the shape of the overlapping portion of the electrode layer 305 and the electrode layer 307. It should be noted that other shapes of cavities, such as hexagons, pentagons, etc., known to those skilled in the art, may also be applied to the embodiments of the present invention. In this embodiment, the side cavity 308 is adjacent to a first side of the cavity 303 and the side cavity 309 is adjacent to a second side of the cavity 303.

Fig. 4a is a schematic structural diagram of a section a of a bulk acoustic wave resonator 400 according to an embodiment of the present invention.

As shown in fig. 4a, an embodiment of the present invention provides a bulk acoustic wave resonator device 400 including: a substrate 401; the middle layer 402 is positioned on the substrate 401, the upper surface side of the middle layer 402 comprises a cavity 403 and a groove 404, wherein the groove 404 is positioned on one side of the cavity 403 and is communicated with the cavity 403, and the depth of the groove 404 is smaller than that of the cavity 403; an electrode layer 405, a first end 405a of the electrode layer 405 being located in the cavity 403, and a second end 405b of the electrode layer 405 being located in the groove 404, wherein the depth of the groove 404 is equal to the thickness of the electrode layer 405; a piezoelectric layer 406 disposed on the electrode layer 405 and the intermediate layer 402, covering the cavity 403, wherein the piezoelectric layer 406 includes a first side 406a and a second side 406b opposite to the first side 406a, and the electrode layer 405 and the intermediate layer 402 are disposed on the first side 406 a; an electrode layer 407 on said second side 406b on said piezoelectric layer 406; an edge structure 408 located on the second side 406b and on the electrode layer 407, wherein the piezoelectric layer 406 and the edge structure 408 are located on two sides of the electrode layer 407, respectively, and the edge structure 408 includes a peripheral portion 408a located on an edge of a portion of the electrode layer 407 coinciding with the electrode layer 405; and a side cavity 409 between the intermediate layer 402 and the electrode layer 405, embedded in the intermediate layer 402, and communicating with the cavity 403; wherein the depth of the side cavity 409 is less than the depth of the cavity 403.

As can be seen from fig. 4a, the resonance region 410 (i.e., the overlapped region of the electrode layer 405 and the electrode layer 407) is suspended with respect to the cavity 403, and has no overlap with the intermediate layer 402, so that the acoustic wave of the transverse mode at the horizontal edge of the resonance region 410 is blocked from leaking into the intermediate layer 402, and the Q value can be improved.

In this embodiment, the side cavity 409 is located at the outer side of the resonance region 410 in the horizontal direction.

In this embodiment, the material of the substrate 401 includes, but is not limited to, at least one of the following: silicon, silicon carbide, glass, gallium arsenide, gallium nitride, ceramics.

In this embodiment, the material of the intermediate layer 402 includes, but is not limited to, at least one of the following: polymer, insulating dielectric, polysilicon. In this embodiment, the polymer includes, but is not limited to, at least one of: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide. In this embodiment, the insulating dielectric includes, but is not limited to, at least one of: aluminum nitride, silicon dioxide, silicon nitride, titanium oxide.

In this embodiment, the material of the electrode layer 405 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium.

In this embodiment, the piezoelectric layer 406 is a flat layer and also covers the upper surface side of the intermediate layer 402. In this embodiment, the material of the piezoelectric layer 406 includes, but is not limited to, at least one of the following: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

In this embodiment, the piezoelectric layer 406 includes a plurality of grains including a first grain and a second grain, wherein the first grain and the second grain are any two grains of the plurality of grains. Those skilled in the art know that the crystal orientation, crystal plane, etc. of the crystal grain can be expressed based on a coordinate system.

In this embodiment, the piezoelectric layer 406 includes a plurality of grains, and the half width of the rocking curve of the crystal formed by the plurality of grains is less than 2.5 degrees.

It should be noted that forming the piezoelectric layer 406 in a plane can make the piezoelectric layer 406 not include a crystal grain with obvious turning, so that the electromechanical coupling coefficient of the resonance device and the Q value of the resonance device can be improved.

In this embodiment, the material of the electrode layer 407 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium.

In this embodiment, a portion of the electrode layer 405 overlapping with the electrode layer 407 is located in the cavity 403; the portion of the electrode 407 that coincides with the electrode 405 is located above the cavity 403.

In this embodiment, the material of the edge structure 408 includes metal. In this embodiment, the material of the edge structure 408 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium. In this embodiment, the material of the edge structure 408 is the same as the material of the electrode layer 407. In another embodiment, the material of the edge structure above the piezoelectric layer and the material of the upper electrode layer may be different.

In this embodiment, the surrounding portion 408a is located in the resonance region 410 and is a surrounding edge of the resonance region 410. In addition, the acoustic impedance of the edge portion 411 in the resonance region 410 is larger than the acoustic impedance of the intermediate portion 412 in the resonance region 410, and the acoustic impedance of the edge portion 411 is larger than the acoustic impedance of the non-resonance region, so that the acoustic wave of the transverse mode is reflected at the edge of the resonance region 410 in the horizontal direction and remains in the resonance region 410, and the Q value can be increased.

In this embodiment, the inner side of the surrounding portion 408a (i.e., the side facing the central axis of the resonator device 400) is a straight surface. In another embodiment, the inner side of the peripheral edge portion may be a sloping surface.

In this embodiment, the cavity 403 is located inside the side cavity 409. In this embodiment, the electrode layer 405 is located on the side cavity 409, and has an overlapping portion with the side cavity 409.

It should be noted that the acoustic impedance of the vacuum state or air in the side cavity 409 is smaller than the acoustic impedance of the electrode layer 405, and the sound wave of the transverse mode is reflected at the boundary between the side cavity 409 and the electrode layer 405, so that the leakage wave propagating towards the intermediate layer 402 in the transverse mode is blocked, and the Q value is improved.

Fig. 4b is a schematic top view of a bulk acoustic wave resonator device 400 according to an embodiment of the present invention.

As shown in fig. 4b, in the present embodiment, the surrounding portion 408a is ring-shaped. In this embodiment, the surrounding portion 408a is octagonal. It should be noted that the peripheral portion with other shapes known to those skilled in the art, such as a hexagon, a pentagon, etc., can also be applied to the embodiment of the present invention.

In the present embodiment, the cavity 403 has an octagonal shape, as shown in fig. 4 b. It should be noted that other shapes of cavities, such as hexagons, pentagons, etc., known to those skilled in the art, may also be applied to the embodiments of the present invention. In this embodiment, the side cavity 409 is adjacent to a first side of the cavity 403.

Fig. 5a is a schematic structural diagram of a section a of a bulk acoustic wave resonator 500 according to an embodiment of the present invention.

As shown in fig. 5a, an embodiment of the present invention provides a bulk acoustic wave resonator device 500 including: a substrate 501; the middle layer 502 is positioned on the substrate 501, the upper surface side of the middle layer 502 comprises a cavity 503 and a groove 504, wherein the groove 504 is positioned on one side of the cavity 503 and is communicated with the cavity 503, and the depth of the groove 504 is smaller than that of the cavity 503; a rim structure 505, including a peripheral portion 505a, said peripheral portion 505a being located in said cavity 503, and an extension portion 505b, one end of said extension portion 505b being connected to said peripheral portion 505a, and the other end of said extension portion 505b being located in said recess 504; an electrode layer 506 positioned on the edge structure 505, a first end 506a of the electrode layer 506 being positioned in the cavity 503 and a second end 506b of the electrode layer 506 being positioned in the groove 504, wherein the depth of the groove 504 is equal to the sum of the thicknesses of the edge structure 505 and the electrode layer 506; a piezoelectric layer 507 disposed on the electrode layer 506 and the intermediate layer 502 and covering the cavity 503, wherein the piezoelectric layer 507 includes a first side 507a and a second side 507b opposite to the first side 507a, and the electrode layer 506 and the intermediate layer 502 are disposed on the first side 507 a; an electrode layer 508 on said second side 507b on said piezoelectric layer 507; the peripheral edge portion 505a is located at an edge of a portion of the electrode layer 506, which overlaps with the electrode layer 508; and a side cavity 509, located at said first side 507a, between said intermediate layer 502 and said piezoelectric layer 507, embedded in said intermediate layer 502, and communicating with said cavity 503, said side cavity 509 contacting said piezoelectric layer 507; wherein the depth of the side cavity 509 is less than the depth of the cavity 503.

As can be seen from fig. 5a, the resonance region 510 (i.e., the overlapped region of the electrode layer 506 and the electrode layer 508) is suspended with respect to the cavity 503, and has no overlap with the intermediate layer 502, so that the acoustic wave of the transverse mode at the horizontal edge of the resonance region 510 is blocked from leaking into the intermediate layer 502, and the Q value can be improved.

In this embodiment, the side cavity 509 is located at the outer side of the resonance region 510 in the horizontal direction.

In this embodiment, the material of the substrate 501 includes, but is not limited to, at least one of the following: silicon, silicon carbide, glass, gallium arsenide, gallium nitride, ceramics.

In this embodiment, the material of the intermediate layer 502 includes, but is not limited to, at least one of the following: polymer, insulating dielectric, polysilicon. In this embodiment, the polymer includes, but is not limited to, at least one of: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide. In this embodiment, the insulating dielectric includes, but is not limited to, at least one of: aluminum nitride, silicon dioxide, silicon nitride, titanium oxide.

In this embodiment, the material of the edge structure 505 includes metal. In this embodiment, the material of the edge structure 505 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium. In this embodiment, the material of the edge structure 505 is the same as the material of the electrode layer 506. In another embodiment, the material of the edge structure under the piezoelectric layer and the material of the lower electrode layer may be different.

In this embodiment, the surrounding edge 505a is located in the resonance region 510 and is a surrounding edge of the resonance region 510. It should be noted that the acoustic impedance of the edge portion 511 in the resonance region 510 is larger than the acoustic impedance of the intermediate portion 512 in the resonance region 510, and the acoustic impedance of the edge portion 511 is larger than the acoustic impedance of the non-resonance region, so that the acoustic wave of the transverse mode is reflected at the edge of the resonance region 510 in the horizontal direction and remains in the resonance region 510, and the Q value can be increased.

In this embodiment, the inner side of the surrounding portion 505a (i.e., the side facing the central axis of the resonator device 500) is a straight surface. In another embodiment, the inner side of the peripheral edge portion may be a sloping surface.

In this embodiment, the material of the electrode layer 506 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium.

In this embodiment, the piezoelectric layer 507 is a flat layer, and also covers the upper surface side of the intermediate layer 502. In this embodiment, the material of the piezoelectric layer 507 includes but is not limited to at least one of the following: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

In this embodiment, the piezoelectric layer 507 includes a plurality of crystal grains including a first crystal grain and a second crystal grain, wherein the first crystal grain and the second crystal grain are any two crystal grains of the plurality of crystal grains. Those skilled in the art know that the crystal orientation, crystal plane, etc. of the crystal grain can be expressed based on a coordinate system.

In this embodiment, the piezoelectric layer 507 includes a plurality of crystal grains, and a half-width of a rocking curve of a crystal formed by the plurality of crystal grains is less than 2.5 degrees.

It should be noted that forming the piezoelectric layer 507 on a plane can make the piezoelectric layer 507 not include crystal grains with obvious turning, so that the electromechanical coupling coefficient of the resonance device and the Q value of the resonance device can be improved.

In this embodiment, the material of the electrode layer 508 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium.

In this embodiment, a portion of the electrode layer 506 that overlaps with the electrode layer 508 is located in the cavity 503; the portion of the electrode 508 coinciding with the electrode 506 is located above the cavity 503.

In this embodiment, the cavity 503 is located inside the side cavity 509. In this embodiment, the electrode layer 508 is located above the side cavity 509 and has an overlapping portion with the side cavity 509.

It should be noted that the acoustic impedance of the vacuum state or air in the side cavity 509 is smaller than that of the piezoelectric layer 507, and the acoustic wave of the transverse mode is reflected at the boundary between the side cavity 509 and the piezoelectric layer 507, so that the leakage wave propagating towards the intermediate layer 502 in the transverse mode is blocked, and the Q value is improved.

Fig. 5b is a schematic top view of a bulk acoustic wave resonator device 500 according to an embodiment of the present invention.

As shown in fig. 5b, in the present embodiment, the surrounding portion 505a is ring-shaped. In this embodiment, the surrounding portion 505a is octagonal. It should be noted that the peripheral portion with other shapes known to those skilled in the art, such as a hexagon, a pentagon, etc., can also be applied to the embodiment of the present invention.

In the present embodiment, the cavity 503 is octagonal, as shown in fig. 5 b. It should be noted that other shapes of cavities, such as hexagons, pentagons, etc., known to those skilled in the art, may also be applied to the embodiments of the present invention. In this embodiment, the side cavity 509 is adjacent to a first side of the cavity 503.

Fig. 6a is a schematic structural diagram of a section a of a bulk acoustic wave resonator 600 according to an embodiment of the present invention.

As shown in fig. 6a, an embodiment of the present invention provides a bulk acoustic wave resonator device 600 including: a substrate 601; the middle layer 602 is positioned on the substrate 601, the upper surface side of the middle layer 602 comprises a cavity 603 and a groove 604, wherein the groove 604 is positioned on one side of the cavity 603 and is communicated with the cavity 603, and the depth of the groove 604 is smaller than that of the cavity 603; a rim structure 605 comprising a peripheral portion 605a, said peripheral portion 605a being located within said cavity 603, and an extension portion 605b, one end of said extension portion 605b being connected to said peripheral portion 605a, the other end of said extension portion 605b being located within said recess 604; an electrode layer 606 on the edge structure 605, a first end 606a of the electrode layer 606 being located in the cavity 603 and a second end 606b of the electrode layer 606 being located in the recess 604, wherein the depth of the recess 604 is equal to the sum of the thicknesses of the edge structure 605 and the electrode layer 606; a piezoelectric layer 607 disposed on the electrode layer 606 and the intermediate layer 602, covering the cavity 603, wherein the piezoelectric layer 607 includes a first side 607a and a second side 607b opposite to the first side 607a, and the electrode layer 606 and the intermediate layer 602 are disposed on the first side 607 a; an electrode layer 608 located on the second side 607b and located on the piezoelectric layer 607, wherein the peripheral portion 605a is located at a partial edge of a portion overlapping with the electrode layer 608 on the electrode layer 606; an edge structure 609 positioned on the second side 607b and positioned on the electrode layer 608, wherein the piezoelectric layer 607 and the edge structure 609 are positioned on two sides of the electrode layer 608, respectively, and the edge structure 609 comprises a peripheral portion 609a positioned on a partial edge of a portion of the electrode layer 608, which coincides with the electrode layer 606; wherein the peripheral part 605a and the peripheral part 609a are partially overlapped to form a peripheral edge; a side cavity 610 at said first side 607a, between said intermediate layer 602 and said piezoelectric layer 607, embedded in said intermediate layer 602, and communicating with said cavity 603, said side cavity 610 contacting said piezoelectric layer 607; and a side cavity 611, located between the intermediate layer 602 and the edge structure 605, embedded in the intermediate layer 602, communicating with the cavity 603; wherein the depth of the side cavity 610 is less than the depth of the cavity 603, and the depth of the side cavity 611 is less than the depth of the cavity 603.

As can be seen from fig. 6a, the resonance region 612 (i.e., the overlapped region of the electrode layer 606 and the electrode layer 608) is suspended from the cavity 603, and has no overlap with the intermediate layer 602, so that the acoustic wave of the transverse mode at the horizontal edge of the resonance region 612 is blocked from leaking into the intermediate layer 602, and the Q value can be improved.

In this embodiment, the side cavity 610 and the side cavity 611 are located at the outer side of the resonance region 612 in the horizontal direction.

In this embodiment, the material of the substrate 601 includes, but is not limited to, at least one of the following: silicon, silicon carbide, glass, gallium arsenide, gallium nitride, ceramics.

In this embodiment, the material of the intermediate layer 602 includes, but is not limited to, at least one of the following: polymer, insulating dielectric, polysilicon. In this embodiment, the polymer includes, but is not limited to, at least one of: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide. In this embodiment, the insulating dielectric includes, but is not limited to, at least one of: aluminum nitride, silicon dioxide, silicon nitride, titanium oxide.

In this embodiment, the material of the edge structure 605 includes metal. In this embodiment, the material of the edge structure 605 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium. In this embodiment, the material of the edge structure 605 and the material of the electrode layer 606 are the same. In another embodiment, the material of the first edge structure under the piezoelectric layer and the material of the lower electrode layer may be different.

In this embodiment, the material of the electrode layer 606 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium.

In this embodiment, the piezoelectric layer 607 is a flat layer and also covers the upper surface side of the intermediate layer 602. In this embodiment, the material of the piezoelectric layer 607 includes, but is not limited to, at least one of the following: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

In this embodiment, the piezoelectric layer 607 includes a plurality of grains including a first grain and a second grain, where the first grain and the second grain are any two grains of the plurality of grains. Those skilled in the art know that the crystal orientation, crystal plane, etc. of the crystal grain can be expressed based on a coordinate system.

In this embodiment, the piezoelectric layer 607 includes a plurality of crystal grains, and the half width of the rocking curve of the crystal formed by the plurality of crystal grains is less than 2.5 degrees.

It should be noted that forming the piezoelectric layer 607 on a plane can make the piezoelectric layer 607 not include crystal grains with obvious turning directions, so that the electromechanical coupling coefficient of the resonance device and the Q value of the resonance device can be improved.

In this embodiment, the material of the electrode layer 608 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium.

In this embodiment, a portion of the electrode layer 606 overlapping with the electrode layer 608 is located in the cavity 603; the portion of the electrode layer 608 overlapping the electrode layer 606 is located above the cavity 603.

In this embodiment, the material of the edge structure 609 includes a metal. In this embodiment, the material of the edge structure 609 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium. In this embodiment, the material of the edge structure 609 is the same as the material of the electrode layer 608. In another embodiment, the material of the second edge structure above the piezoelectric layer and the material of the upper electrode layer may be different.

In this embodiment, the peripheral portion 605a is located in the resonance region 612, the peripheral portion 609a is located in the resonance region 612, and the peripheral portion 605a and the peripheral portion 609a partially overlap to form a peripheral edge of the resonance region 612. The acoustic impedance of the edge portion 613 in the resonance region 612 is higher than that of the intermediate portion 614 in the resonance region 612, and the acoustic impedance of the edge portion 613 is higher than that of the non-resonance region, so that the acoustic wave of the transverse mode is reflected at the horizontal edge of the resonance region 612 and remains in the resonance region 612, thereby increasing the Q value.

In this embodiment, the inner side of the surrounding portion 605a (i.e., the side facing the central axis of the resonator device 600) is a straight surface, and the inner side of the surrounding portion 609a is a straight surface. In another embodiment, the inner side of the peripheral edge portion may be a sloping surface.

In this embodiment, the cavity 603 is located inside the side cavity 610, and the cavity 603 is also located inside the side cavity 611. In this embodiment, the electrode layer 608 is located above the side cavity 610, and has an overlapping portion with the side cavity 610; the edge structure 605 is located on the side cavity 611 with an overlap with the side cavity 611.

It should be noted that the acoustic impedance of the vacuum state or air in the side cavity 610 is smaller than the acoustic impedance of the piezoelectric layer 607, the acoustic impedance of the vacuum state or air in the side cavity 611 is smaller than the acoustic impedance of the edge structure 605, and the acoustic wave of the transverse mode is reflected at the boundary between the side cavity 610 and the piezoelectric layer 607 and the boundary between the side cavity 611 and the edge structure 605, so that the leakage wave propagating toward the intermediate layer 602 in the transverse mode is blocked, and the Q value is increased.

Fig. 6b is a schematic top view of a bulk acoustic wave resonator device 600 according to an embodiment of the present invention.

As shown in fig. 6b, in the present embodiment, the peripheral portion 605a and the peripheral portion 609a have a coincidence portion 615, which forms a peripheral edge of the resonance region 612 and blocks lateral wave leakage. In this embodiment, the peripheral portion formed by the peripheral portion 605a and the peripheral portion 609a is annular. In this embodiment, the peripheral edge formed by the peripheral edge portion 605a and the peripheral edge portion 609a is octagonal. It should be noted that other shapes of the surrounding edge, such as a hexagon, a pentagon, etc., known to those skilled in the art, can also be applied to the embodiments of the present invention.

In the present embodiment, the cavity 603 is octagonal, as shown in fig. 6 b. It should be noted that other shapes of cavities, such as hexagons, pentagons, etc., known to those skilled in the art, may also be applied to the embodiments of the present invention. In this embodiment, the side cavity 610 is adjacent to seven sides of the cavity 603, and the side cavity 611 is adjacent to an eighth side of the cavity 603.

Fig. 6c is a schematic structural diagram of a section B of a bulk acoustic wave resonator 600 according to an embodiment of the present invention. Fig. 6c shows a cross-section B of the side cavity 610 and the overlap 615.

Fig. 7 is a schematic structural diagram of a section a of a bulk acoustic wave resonator device 700 according to an embodiment of the present invention.

As shown in fig. 7, an embodiment of the present invention provides a bulk acoustic wave resonator device 700 including: a substrate 701; the middle layer 702 is positioned on the substrate 701, the upper surface side of the middle layer 702 comprises a cavity 703 and a groove 704, wherein the groove 704 is positioned on one side of the cavity 703 and is communicated with the cavity 703, and the depth of the groove 704 is smaller than that of the cavity 703; a rim structure 705 including a peripheral portion 705a, the peripheral portion 705a being located in the cavity 703, and an extension portion 705b, one end of the extension portion 705b being connected to the peripheral portion 705a, and the other end of the extension portion 705b being located in the groove 704; an electrode layer 706 located on the edge structure 705, a first end 706a of the electrode layer 706 being located in the cavity 703 and a second end 706b of the electrode layer 706 being located in the groove 704, wherein the depth of the groove 704 is equal to the sum of the thicknesses of the edge structure 705 and the electrode layer 706; a piezoelectric layer 707 located on the electrode layer 706 and the intermediate layer 702 and covering the cavity 703, wherein the piezoelectric layer 707 includes a first side 707a and a second side 707b opposite to the first side 707a, and the electrode layer 706 and the intermediate layer 702 are located on the first side 707 a; an electrode layer 708 on the second side 707b and on the piezoelectric layer 707, wherein the peripheral portion 705a is located at an edge of a portion of the electrode layer 706 that overlaps the electrode layer 708; an edge structure 709 located on the second side 707b and located on the electrode layer 708, wherein the piezoelectric layer 707 and the edge structure 709 are respectively located on two sides of the electrode layer 708, and the edge structure 709 includes a peripheral portion 709a located on an edge of a portion of the electrode layer 708 coinciding with the electrode layer 706; wherein the surrounding edge part 705a and the surrounding edge part 709a are overlapped to form a surrounding edge; a side cavity 710 located at said first side 707a, between said intermediate layer 702 and said piezoelectric layer 707, embedded in said intermediate layer 702, and communicating with said cavity 703, said side cavity 710 contacting said piezoelectric layer 707; and a side cavity 711, located between said intermediate layer 702 and said edge structure 705, embedded in said intermediate layer 702, communicating with said cavity 703; wherein the depth of the side cavity 710 is smaller than the depth of the cavity 703, and the depth of the side cavity 711 is smaller than the depth of the cavity 703.

As can be seen from fig. 7a, the resonance region 712 (i.e. the overlapping area of the electrode layer 706 and the electrode layer 708) is suspended from the cavity 703 and does not overlap with the intermediate layer 702, so that the acoustic waves of the transverse mode at the horizontal edge of the resonance region 712 are blocked from leaking into the intermediate layer 702, and the Q value can be increased.

In this embodiment, the side cavity 710 and the side cavity 711 are located at the outer side of the resonance region 712 in the horizontal direction.

In this embodiment, the material of the substrate 701 includes, but is not limited to, at least one of the following: silicon, silicon carbide, glass, gallium arsenide, gallium nitride, ceramics.

In this embodiment, the material of the intermediate layer 702 includes, but is not limited to, at least one of the following: polymer, insulating dielectric, polysilicon. In this embodiment, the polymer includes, but is not limited to, at least one of: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide. In this embodiment, the insulating dielectric includes, but is not limited to, at least one of: aluminum nitride, silicon dioxide, silicon nitride, titanium oxide.

In this embodiment, the material of the edge structure 705 includes a metal. In this embodiment, the material of the edge structure 705 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium. In this embodiment, the material of the edge structure 705 is the same as the material of the electrode layer 706. In another embodiment, the material of the first edge structure under the piezoelectric layer and the material of the lower electrode layer may be different.

In this embodiment, the material of the electrode layer 706 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium.

In this embodiment, the piezoelectric layer 707 is a flat layer, and also covers the upper surface side of the intermediate layer 702. In this embodiment, the material of the piezoelectric layer 707 includes, but is not limited to, at least one of: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

In this embodiment, the piezoelectric layer 707 includes a plurality of grains including a first grain and a second grain, where the first grain and the second grain are any two grains of the plurality of grains. Those skilled in the art know that the crystal orientation, crystal plane, etc. of the crystal grain can be expressed based on a coordinate system.

In this embodiment, the piezoelectric layer 707 includes a plurality of crystal grains, and a rocking curve half-width of a crystal formed by the plurality of crystal grains is less than 2.5 degrees.

It should be noted that forming the piezoelectric layer 707 on a plane may enable the piezoelectric layer 707 to include no crystal grains with obvious turning directions, so that the electromechanical coupling coefficient of the resonant device and the Q value of the resonant device may be improved.

In this embodiment, the material of the electrode layer 708 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium.

In this embodiment, a portion of the electrode layer 706 overlapping with the electrode layer 708 is located in the cavity 703; the portion of the electrode 708 coinciding with the electrode 706 is located above the cavity 703.

In this embodiment, the material of the edge structure 709 includes a metal. In this embodiment, the material of the edge structure 709 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium. In this embodiment, the material of the edge structure 709 is the same as the material of the electrode layer 708. In another embodiment, the material of the second edge structure above the piezoelectric layer and the material of the upper electrode layer may be different.

In this embodiment, the peripheral portion 705a is located in the resonance region 712, the peripheral portion 709a is located in the resonance region 712, and the peripheral portion 705a and the peripheral portion 709a are overlapped to form a peripheral edge of the resonance region 712. The acoustic impedance of the edge portion 713 in the resonance region 712 is higher than the acoustic impedance of the intermediate portion 714 in the resonance region 712, and the acoustic impedance of the edge portion 713 is higher than the acoustic impedance of the non-resonance region, so that the acoustic wave of the transverse mode is reflected at the horizontal edge of the resonance region 712 and remains in the resonance region 712, thereby increasing the Q value.

In this embodiment, the inner side of the surrounding portion 705a (i.e., the side facing the central axis of the resonator device 700) is a straight surface, and the inner side of the surrounding portion 709a is a straight surface. In another embodiment, the inner side of the peripheral edge portion may be a sloping surface.

In this embodiment, the cavity 703 is located inside the side cavity 710, and the cavity 703 is also located inside the side cavity 711. In this embodiment, the electrode layer 708 is located above the side cavity 710, and has an overlapping portion with the side cavity 710; the edge structure 705 is located on the side cavity 711, with an overlap with the side cavity 711.

It should be noted that the acoustic impedance of the vacuum state or air in the side cavity 710 is smaller than the acoustic impedance of the piezoelectric layer 707, the acoustic impedance of the vacuum state or air in the side cavity 711 is smaller than the acoustic impedance of the edge structure 705, and the acoustic wave of the transverse mode is reflected at the boundary between the side cavity 710 and the piezoelectric layer 707 and the boundary between the side cavity 711 and the edge structure 705, so that the leakage wave propagating towards the intermediate layer 702 in the transverse mode is blocked, and the Q value is improved.

Fig. 7b is a schematic top view of a bulk acoustic wave resonator device 700 according to an embodiment of the present invention.

As shown in fig. 7b, in the present embodiment, the peripheral portion 705a coincides with the peripheral portion 709a to form a peripheral edge of the resonance region 712, so as to block lateral wave leakage. In this embodiment, the peripheral edge portion 705a and the peripheral edge portion 709a form a peripheral edge in a ring shape. In this embodiment, the surrounding edge formed by the surrounding edge portion 705a and the surrounding edge portion 709a is octagonal. It should be noted that other shapes of the surrounding edge, such as a hexagon, a pentagon, etc., known to those skilled in the art, can also be applied to the embodiments of the present invention.

In the present embodiment, the cavity 703 is octagonal, as shown in fig. 7 b. It should be noted that other shapes of cavities, such as hexagons, pentagons, etc., known to those skilled in the art, may also be applied to the embodiments of the present invention. In this embodiment, the side cavity 710 is adjacent to five sides of the cavity 703, and the side cavity 711 is adjacent to a sixth side of the cavity 703.

Fig. 8 is a schematic structural diagram of a section a of a bulk acoustic wave resonator 800 according to an embodiment of the present invention.

As shown in fig. 8, an embodiment of the present invention provides a bulk acoustic wave resonator device 800 including: a substrate 801; the middle layer 802 is positioned on the substrate 801, the upper surface side of the middle layer 802 comprises a cavity 803 and a groove 804, wherein the groove 804 is positioned on one side of the cavity 803 and is communicated with the cavity 803, and the depth of the groove 804 is smaller than that of the cavity 803; an electrode layer 805, a first end 805a of the electrode layer 805 is located in the cavity 803, a second end 805b of the electrode layer 805 is located in the groove 804, wherein the depth of the groove 804 is equal to the thickness of the electrode layer 805; a piezoelectric layer 806 disposed on the electrode layer 805 and the intermediate layer 802 covering the cavity 803, wherein the piezoelectric layer 806 includes a first side 806a and a second side 806b opposite to the first side 806a, and the electrode layer 805 and the intermediate layer 802 are disposed on the first side 806 a; an electrode layer 807 on the second side 806b on the piezoelectric layer 806; an edge structure 808 on the piezoelectric layer 806 at the second side 806b, wherein the edge structure 808 comprises a peripheral portion 808a, the electrode layer 807 is located in the middle of the peripheral portion 808a (i.e. the inner side, the side facing the central axis of the resonator device 800), and the peripheral portion 808a coincides with the electrode layer 805; and a side cavity 809, located between the intermediate layer 802 and the electrode layer 805, embedded in the intermediate layer 802, and communicating with the cavity 803; wherein the depth of the side cavity 809 is less than the depth of the cavity 803.

As can be seen from fig. 8, the resonance region 810 (i.e., the overlapped region of the electrode layer 805, the electrode layer 807 and the surrounding portion 808 a) is suspended from the cavity 803, and has no overlap with the intermediate layer 802, so that the leakage of the acoustic wave of the transverse mode at the horizontal edge of the resonance region 810 into the intermediate layer 802 can be blocked, and the Q value can be improved.

In this embodiment, the side cavity 809 is located at the outer side of the resonance region 810 in the horizontal direction.

In this embodiment, the material of the substrate 801 includes, but is not limited to, at least one of the following: silicon, silicon carbide, glass, gallium arsenide, gallium nitride, ceramics.

In this embodiment, the material of the intermediate layer 802 includes, but is not limited to, at least one of the following: polymer, insulating dielectric, polysilicon. In this embodiment, the polymer includes, but is not limited to, at least one of: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide. In this embodiment, the insulating dielectric includes, but is not limited to, at least one of: aluminum nitride, silicon dioxide, silicon nitride, titanium oxide.

In this embodiment, the material of the electrode layer 805 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium.

In this embodiment, the piezoelectric layer 806 is a flat layer and also covers the upper surface side of the intermediate layer 802. In this embodiment, the material of the piezoelectric layer 806 includes, but is not limited to, at least one of: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

In this embodiment, the piezoelectric layer 806 includes a plurality of grains including a first grain and a second grain, wherein the first grain and the second grain are any two grains of the plurality of grains. Those skilled in the art know that the crystal orientation, crystal plane, etc. of the crystal grain can be expressed based on a coordinate system.

In this embodiment, the piezoelectric layer 806 includes a plurality of grains, and the half width of the rocking curve of the crystal formed by the plurality of grains is less than 2.5 degrees.

It should be noted that forming the piezoelectric layer 806 in a plane can make the piezoelectric layer 806 not include a crystal grain with obvious turning, so as to improve the electromechanical coupling coefficient of the resonance device and the Q value of the resonance device.

In this embodiment, the material of the electrode layer 807 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium.

In this embodiment, the portion of the electrode layer 805 overlapping with the electrode layer 807 is located in the cavity 803; the portion of the electrode 807 that coincides with the electrode 805 is located above the cavity 803.

In this embodiment, the material of the edge structure 808 includes metal. In this embodiment, the material of the edge structure 808 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium. In this embodiment, the material of the edge structure 808 and the material of the electrode layer 807 are the same. In another embodiment, the material of the edge structure on the piezoelectric layer and the material of the upper electrode layer may be different.

In this embodiment, the thickness of the edge structure 808 is greater than the thickness of the electrode layer 807. In another embodiment, the thickness of the edge structure on the piezoelectric layer is less than the thickness of the upper electrode layer. In another embodiment, the thickness of the edge structure on the piezoelectric layer is equal to the thickness of the upper electrode layer.

In this embodiment, the surrounding edge 808a is located in the resonance region 810 and is a surrounding edge of the resonance region 810. In addition, since the acoustic impedance of the edge portion 811 in the resonance region 810 is higher than the acoustic impedance of the intermediate portion 812 in the resonance region 810 and the acoustic impedance of the edge portion 811 is higher than the acoustic impedance of the non-resonance region, the acoustic wave of the transverse mode is reflected at the horizontal edge of the resonance region 810 and remains in the resonance region 810, and the Q value can be increased.

In this embodiment, the inside of the surrounding portion 808a is a straight surface. In another embodiment, the inner side of the peripheral edge portion may be a sloping surface.

In this embodiment, the cavity 803 is located inside the side cavity 809. In this embodiment, the electrode layer 805 is located on the side cavity 809, and has an overlapping portion with the side cavity 809.

It should be noted that the acoustic impedance of the vacuum state or air in the side cavity 809 is smaller than the acoustic impedance of the electrode layer 805, and the acoustic wave of the transverse mode is reflected at the boundary between the side cavity 809 and the electrode layer 805, so that the leakage wave propagating towards the intermediate layer 802 in the transverse mode is blocked, and the Q value is improved.

Fig. 9 is a schematic structural diagram of a section a of a bulk acoustic wave resonator 900 according to an embodiment of the present invention.

As shown in fig. 9, an embodiment of the present invention provides a bulk acoustic wave resonator device 900 including: a substrate 901; the middle layer 902 is positioned on the substrate 901, the upper surface side of the middle layer 902 comprises a cavity 903 and a groove 904, wherein the groove 904 is positioned on one side of the cavity 903 and is communicated with the cavity 903, and the depth of the groove 904 is smaller than that of the cavity 903; an electrode layer 905 positioned within the cavity 903; a rim structure 906 including a peripheral portion 906a, the peripheral portion 906a being located in the cavity 903, the electrode layer 905 being located in the middle of the peripheral portion 906a (i.e. the inner side, the side facing the central axis of the resonator device 900), and an extension portion 906b, one end of the extension portion 906b being connected to the peripheral portion 906a, the other end of the extension portion 906b being located in the recess 904, wherein the depth of the recess 904 is equal to the thickness of the rim structure 906; a piezoelectric layer 907 disposed on the electrode layer 905, the edge structure 906 and the intermediate layer 902 to cover the cavity 903, wherein the piezoelectric layer 907 includes a first side 907a and a second side 907b opposite to the first side 907a, and the electrode layer 905, the edge structure 906 and the intermediate layer 902 are disposed on the first side 907 a; an electrode layer 908 on the second side 907b on the piezoelectric layer 907, the peripheral portion 906a coinciding with the electrode layer 908; and a side cavity 909 located at said first side 907a, located between said intermediate layer 902 and said piezoelectric layer 907, embedded in said intermediate layer 902, and communicating with said cavity 903, said side cavity 909 contacting said piezoelectric layer 907; wherein the depth of the side cavity 909 is less than the depth of the cavity 903.

As can be seen from fig. 9, the resonance region 910 (i.e., the overlapping region of the electrode layer 905 and the peripheral portion 906a with the electrode layer 908) is suspended with respect to the cavity 903 and does not overlap with the intermediate layer 902, so that the acoustic waves of the transverse mode at the horizontal edge of the resonance region 910 are prevented from leaking into the intermediate layer 902, and the Q value can be improved.

In this embodiment, the side cavity 909 is located at the outer side of the resonance region 910 in the horizontal direction.

In this embodiment, the material of the substrate 901 includes, but is not limited to, at least one of the following: silicon, silicon carbide, glass, gallium arsenide, gallium nitride, ceramics.

In this embodiment, the material of the intermediate layer 902 includes, but is not limited to, at least one of the following: polymer, insulating dielectric, polysilicon. In this embodiment, the polymer includes, but is not limited to, at least one of: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide. In this embodiment, the insulating dielectric includes, but is not limited to, at least one of: aluminum nitride, silicon dioxide, silicon nitride, titanium oxide.

In this embodiment, the material of the electrode layer 905 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium.

In this embodiment, the material of the edge structure 906 includes a metal. In this embodiment, the material of the edge structure 906 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium. In this embodiment, the material of the edge structure 906 is the same as the material of the electrode layer 905. In another embodiment, the material of the edge structure under the piezoelectric layer and the material of the lower electrode layer may be different.

In this embodiment, the thickness of the edge structure 906 is greater than the thickness of the electrode layer 905. In another embodiment, the thickness of the edge structure under the piezoelectric layer is less than the thickness of the lower electrode layer. In another embodiment, the thickness of the edge structure under the piezoelectric layer is equal to the thickness of the lower electrode layer.

In this embodiment, the surrounding portion 906a is located in the resonance region 910 and is a surrounding edge of the resonance region 910. In addition, the acoustic impedance of the edge portion 911 in the resonance region 910 is higher than the acoustic impedance of the intermediate portion 912 in the resonance region 910, and the acoustic impedance of the edge portion 911 is higher than the acoustic impedance of the non-resonance region, so that the acoustic wave of the transverse mode is reflected at the horizontal edge of the resonance region 910 and remains in the resonance region 910, and the Q value can be increased.

In this embodiment, the inside of the surrounding portion 906a is a straight surface. In another embodiment, the inner side of the peripheral edge portion may be a sloping surface.

In this embodiment, the piezoelectric layer 907 is a flat layer and also covers the upper surface side of the intermediate layer 902. In this embodiment, the material of the piezoelectric layer 907 includes, but is not limited to, at least one of the following: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

In this embodiment, the piezoelectric layer 907 includes a plurality of grains including a first grain and a second grain, wherein the first grain and the second grain are any two grains of the plurality of grains. Those skilled in the art know that the crystal orientation, crystal plane, etc. of the crystal grain can be expressed based on a coordinate system.

In this embodiment, the piezoelectric layer 907 includes a plurality of crystal grains, and the half width of the rocking curve of the crystal formed by the plurality of crystal grains is less than 2.5 degrees.

It should be noted that forming the piezoelectric layer 907 on a plane may make the piezoelectric layer 907 not include grains with obvious turning, so that the electromechanical coupling coefficient of the resonance device and the Q value of the resonance device may be improved.

In this embodiment, the material of the electrode layer 908 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium.

In this embodiment, a portion of the electrode layer 905 overlapping with the electrode layer 908 is located in the cavity 903; the portion of the electrode 908 that coincides with the electrode 905 is located above the cavity 903.

In this embodiment, the cavity 903 is located inside the side cavity 909. In this embodiment, the electrode layer 908 is located above the side cavity 909, and has an overlapping portion with the side cavity 909.

It should be noted that the acoustic impedance of the vacuum state or air in the side cavity 909 is smaller than that of the piezoelectric layer 907, and the acoustic wave of the transverse mode is reflected at the boundary between the side cavity 909 and the piezoelectric layer 907, so that the leakage wave propagating towards the intermediate layer 902 in the transverse mode is blocked, and the Q value is improved.

Fig. 10a is a schematic structural diagram of a section a of a bulk acoustic wave resonator 1000 according to an embodiment of the present invention.

As shown in fig. 10a, an embodiment of the present invention provides a bulk acoustic wave resonator 1000 including: a substrate 1001; the middle layer 1002 is positioned on the substrate 1001, the upper surface side of the middle layer 1002 comprises a cavity 1003 and a groove 1004, wherein the groove 1004 is positioned on one side of the cavity 1003 and is communicated with the cavity 1003, and the depth of the groove 1004 is smaller than that of the cavity 1003; an electrode layer 1005 located within the cavity 1003; an edge structure 1006, including a peripheral portion 1006a, the peripheral portion 1006a being located in the cavity 1003 and beside a part of an edge of the electrode layer 1005, the electrode layer 1005 being located inside the peripheral portion 1006a (i.e. towards a side of a central axis of the resonator device 1000), and an extension portion 1006b, one end of the extension portion 1006b being connected to the peripheral portion 1006a, and the other end of the extension portion 1006b being located in the groove 1004, wherein a depth of the groove 1004 is equal to a thickness of the edge structure 1006; a piezoelectric layer 1007 positioned on the electrode layer 1005, the edge structure 1006, and the intermediate layer 1002, covering the cavity 1003, wherein the piezoelectric layer 1007 comprises a first side 1007a and a second side 1007b opposite to the first side 1007a, and the electrode layer 1005, the edge structure 1006, and the intermediate layer 1002 are positioned on the first side 1007 a; an electrode layer 1008 on the second side 1007b and on the piezoelectric layer 1007, the peripheral portion 1006a coinciding with the electrode layer 1008; an edge structure 1009 located on the second side 1007b and on the piezoelectric layer 1007, wherein the edge structure 1009 includes a peripheral portion 1009a located beside a partial edge of the electrode layer 1008, the electrode layer 1008 is located inside the peripheral portion 1009a, and the peripheral portion 1009a coincides with the electrode layer 1005; the surrounding edge part 1006a and the surrounding edge part 1009a are partially overlapped to form a surrounding edge; a side cavity 1010 located on said first side 1007a, between said intermediate layer 1002 and said piezoelectric layer 1007, embedded in said intermediate layer 1002, and communicating with said cavity 1003, said side cavity 1010 contacting said piezoelectric layer 1007; and a side cavity 1011 located between said middle layer 1002 and said edge structure 1006, embedded in said middle layer 1002, and communicating with said cavity 1003; wherein the depth of the side cavity 1010 is less than the depth of the cavity 1003, and the depth of the side cavity 1011 is less than the depth of the cavity 1003.

As can be seen from fig. 10a, the resonant region 1012 (i.e., the overlapping region between the electrode layer 1005 and the peripheral portion 1006a and the electrode layer 1008 and the peripheral portion 1009 a) is suspended from the cavity 1003, and does not overlap with the intermediate layer 1002, so that the leakage of the acoustic wave of the lateral mode at the edge side of the resonant region 1012 in the horizontal direction into the intermediate layer 1002 can be blocked, and the Q value can be improved.

In this embodiment, the side cavity 1010 and the side cavity 1011 are located at the outer side of the resonant region 1012 in the horizontal direction.

In this embodiment, the material of the substrate 1001 includes, but is not limited to, at least one of the following: silicon, silicon carbide, glass, gallium arsenide, gallium nitride, ceramics.

In this embodiment, the material of the intermediate layer 1002 includes, but is not limited to, at least one of the following: polymer, insulating dielectric, polysilicon. In this embodiment, the polymer includes, but is not limited to, at least one of: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide. In this embodiment, the insulating dielectric includes, but is not limited to, at least one of: aluminum nitride, silicon dioxide, silicon nitride, titanium oxide.

In this embodiment, the material of the electrode layer 1005 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium.

In this embodiment, the material of the edge structure 1006 includes a metal. In this embodiment, the material of the edge structure 1006 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium. In this embodiment, the material of the edge structure 1006 is the same as the material of the electrode layer 1005. In another embodiment, the material of the first edge structure under the piezoelectric layer and the material of the lower electrode layer may be different.

In this embodiment, the thickness of the edge structure 1006 is greater than the thickness of the electrode layer 1005. In another embodiment, a thickness of the first edge structure under the piezoelectric layer is less than a thickness of the lower electrode layer. In another embodiment, a thickness of the first edge structure under the piezoelectric layer is equal to a thickness of the lower electrode layer.

In this embodiment, the piezoelectric layer 1007 is a flat layer and also covers the upper surface side of the intermediate layer 1002. In this embodiment, the material of the piezoelectric layer 1007 includes, but is not limited to, at least one of the following: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

In this embodiment, the piezoelectric layer 1007 includes a plurality of grains including a first grain and a second grain, where the first grain and the second grain are any two grains of the plurality of grains. Those skilled in the art know that the crystal orientation, crystal plane, etc. of the crystal grain can be expressed based on a coordinate system.

In this embodiment, the piezoelectric layer 1007 includes a plurality of crystal grains, and a half-peak width of a rocking curve of a crystal formed by the plurality of crystal grains is less than 2.5 degrees.

It should be noted that forming the piezoelectric layer 1007 in a plane may make the piezoelectric layer 1007 not include a crystal grain with obvious turning, so that the electromechanical coupling coefficient of the resonance device and the Q value of the resonance device may be improved.

In this embodiment, the material of the electrode layer 1008 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium.

In this embodiment, a portion of the electrode layer 1005, which overlaps with the electrode layer 1008, is located in the cavity 1003; the portion of the electrode 1008 coinciding with the electrode 1005 is located above the cavity 1003.

In this embodiment, the material of the edge structure 1009 includes metal. In this embodiment, the material of the edge structure 1009 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium. In this embodiment, the material of the edge structure 1009 is the same as the material of the electrode layer 1008. In another embodiment, the material of the second edge structure on the piezoelectric layer and the material of the upper electrode layer may be different.

In this embodiment, the thickness of the edge structure 1009 is greater than the thickness of the electrode layer 1008. In another embodiment, a thickness of the second edge structure on the piezoelectric layer is less than a thickness of the upper electrode layer. In another embodiment, a thickness of the second edge structure on the piezoelectric layer is equal to a thickness of the upper electrode layer.

In this embodiment, the surrounding edge portion 1006a is located in the resonance region 1012, the surrounding edge portion 1009a is located in the resonance region 1012, and the surrounding edge portion 1006a and the surrounding edge portion 1009a partially overlap to form a surrounding edge of the resonance region 1012. The acoustic impedance of the edge portion 1013 of the resonance region 1012 is higher than the acoustic impedance of the intermediate portion 1014 of the resonance region 1012, and the acoustic impedance of the edge portion 1013 is higher than the acoustic impedance of the non-resonance region, so that the acoustic wave of the transverse mode is reflected at the horizontal edge of the resonance region 1012 and remains in the resonance region 1012, and the Q value can be increased.

In this embodiment, the inside of the surrounding portion 1006a is a straight surface, and the inside of the surrounding portion 1009a is a straight surface. In another embodiment, the inner side of the peripheral edge portion may be a sloping surface.

In this embodiment, the cavity 1003 is located inside the side cavity 1010, and the cavity 1003 is also located inside the side cavity 1011. In this embodiment, the edge structure 1009 is located above the side cavity 1010, and has an overlapping portion with the side cavity 1010; the edge structure 1006 is located on the side cavity 1011, with an overlap with the side cavity 1011.

It should be noted that the acoustic impedance of the vacuum state or air in the side cavity 1010 is smaller than the acoustic impedance of the piezoelectric layer 1007, the acoustic impedance of the vacuum state or air in the side cavity 1011 is smaller than the acoustic impedance of the edge structure 1006, and the acoustic wave of the transverse mode is reflected at the boundary between the side cavity 1010 and the piezoelectric layer 1007 and the boundary between the side cavity 1011 and the edge structure 1006, so that the leakage wave propagating towards the middle layer 1002 in the transverse mode is blocked, and the Q value is improved.

Fig. 10b is a schematic top view of the bulk acoustic wave resonator 1000 according to the embodiment of the present invention.

As shown in fig. 10b, in the present embodiment, the peripheral portion 1006a and the peripheral portion 1009a have an overlapping portion 1015, which forms a peripheral edge of the resonance region 1012 to block lateral wave leakage. In this embodiment, the surrounding edge formed by the surrounding edge portion 1006a and the surrounding edge portion 1009a is annular. In this embodiment, the surrounding edge formed by the surrounding edge portion 1006a and the surrounding edge portion 1009a is octagonal. It should be noted that other shapes of the surrounding edge, such as a hexagon, a pentagon, etc., known to those skilled in the art, can also be applied to the embodiments of the present invention.

As shown in fig. 10b, in the present embodiment, the cavity 1003 is octagonal. It should be noted that other shapes of cavities, such as hexagons, pentagons, etc., known to those skilled in the art, may also be applied to the embodiments of the present invention. In this embodiment, the side cavity 1010 is adjacent to a first side of the cavity 1003, and the side cavity 1011 is adjacent to a second side of the cavity 1003.

Fig. 10c is a schematic structural diagram of a section B of the bulk acoustic wave resonator 1000 according to the embodiment of the present invention. Fig. 10c shows a cross-sectional B structure of the side cavity 1010 and the overlapping portion 1015.

As shown in fig. 11, the bulk acoustic wave resonator device 1100 according to the embodiment of the present invention includes: a substrate 1101; an intermediate layer 1102 positioned on the substrate 1101, wherein the upper surface side of the intermediate layer 1102 comprises a cavity 1103 and a groove 1104, the groove 1104 is positioned on one side of the cavity 1103 and is communicated with the cavity 1103, and the depth of the groove 1104 is smaller than that of the cavity 1103; an electrode layer 1105 located within the cavity 1103; an edge structure 1106 comprising a peripheral portion 1106a, wherein the peripheral portion 1106a is located in the cavity 1103 and beside the edge of the electrode layer 1105, wherein the electrode layer 1105 is located in the middle of the peripheral portion 1106a (i.e. the inner side, the side facing the central axis of the resonator device 1100), and an extension portion 1106b, wherein one end of the extension portion 1106b is connected to the peripheral portion 1106a, and the other end of the extension portion 1106b is located in the groove 1104, wherein the depth of the groove 1104 is equal to the thickness of the edge structure 1106; a piezoelectric layer 1107 located on the electrode layer 1105, the edge structure 1106, and the middle layer 1102 to cover the cavity 1103, wherein the piezoelectric layer 1107 comprises a first side 1107a and a second side 1107b opposite to the first side 1107a, and the electrode layer 1105, the edge structure 1106, and the middle layer 1102 are located on the first side 1107 a; an electrode layer 1108 on the second side 1107b, on the piezoelectric layer 1107; a rim structure 1109 located at the second side 1107b and located on the piezoelectric layer 1107, wherein the rim structure 1109 includes a peripheral portion 1109a located beside the edge of the electrode layer 1108, the electrode layer 1108 is located in the middle of the peripheral portion 1109a, and the peripheral portion 1109a is overlapped with the peripheral portion 1106a to form a peripheral edge; a side cavity 1110 located at said first side 1107a, located between said middle layer 1102 and said piezoelectric layer 1107, embedded in said middle layer 1102, and communicating with said cavity 1103, said side cavity 1110 contacting said piezoelectric layer 1107; and side cavity 1111, located between said middle layer 1102 and said edge structure 1106, embedded in said middle layer 1102, and in communication with said cavity 1103; wherein the depth of side cavity 1110 is less than the depth of cavity 1103 and the depth of side cavity 1111 is less than the depth of cavity 1103.

As shown in fig. 11, the resonance region 1112 (i.e., the overlapping regions of the electrode layer 1105 and the peripheral portion 1106a, the electrode layer 1108 and the peripheral portion 1109 a) is suspended in the air with respect to the cavity 1103, and does not overlap with the intermediate layer 1102, so that the leakage of the acoustic wave of the transverse mode at the horizontal edge of the resonance region 1112 into the intermediate layer 1102 is blocked, and the Q value can be improved.

In this embodiment, the side cavity 1110 and the side cavity 1111 are located at the outer side of the resonance region 1112 in the horizontal direction.

In this embodiment, the material of the substrate 1101 includes, but is not limited to, at least one of the following: silicon, silicon carbide, glass, gallium arsenide, gallium nitride, ceramics.

In this embodiment, the material of the intermediate layer 1102 includes, but is not limited to, at least one of the following: polymer, insulating dielectric, polysilicon. In this embodiment, the polymer includes, but is not limited to, at least one of: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide. In this embodiment, the insulating dielectric includes, but is not limited to, at least one of: aluminum nitride, silicon dioxide, silicon nitride, titanium oxide.

In this embodiment, the material of the electrode layer 1105 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium.

In this embodiment, the material of the edge structure 1106 includes a metal. In this embodiment, the material of the edge structure 1106 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium. In this embodiment, the material of the edge structure 1106 is the same as the material of the electrode layer 1105. In another embodiment, the material of the first edge structure under the piezoelectric layer and the material of the lower electrode layer may be different.

In this embodiment, the thickness of the edge structure 1106 is greater than the thickness of the electrode layer 1105. In another embodiment, a thickness of the first edge structure under the piezoelectric layer is less than a thickness of the lower electrode layer. In another embodiment, a thickness of the first edge structure under the piezoelectric layer is equal to a thickness of the lower electrode layer.

In this embodiment, the piezoelectric layer 1107 is a planar layer and also covers the top surface side of the middle layer 1102. In this embodiment, the material of the piezoelectric layer 1107 includes, but is not limited to, at least one of: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

In this embodiment, the piezoelectric layer 1107 comprises a plurality of grains including a first grain and a second grain, wherein the first grain and the second grain are any two grains of the plurality of grains. Those skilled in the art know that the crystal orientation, crystal plane, etc. of the crystal grain can be expressed based on a coordinate system.

In this embodiment, the piezoelectric layer 1107 comprises a plurality of grains that form crystals with a rocking curve half-width below 2.5 degrees.

It should be noted that forming the piezoelectric layer 1107 in a plane may result in the piezoelectric layer 1107 not including a significantly turned crystal grain, which may improve the electromechanical coupling coefficient of the resonant device and the Q value of the resonant device.

In this embodiment, the material of the electrode layer 1108 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium.

In this embodiment, a portion of the electrode layer 1105, which overlaps with the electrode layer 1108, is located in the cavity 1103; the portion of the electrode 1108 that coincides with the electrode 1105 is located above the cavity 1103.

In this embodiment, the material of the rim structure 1109 includes metal. In this embodiment, the material of the rim structure 1109 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium. In this embodiment, the material of the edge structure 1109 is the same as the material of the electrode layer 1108. In another embodiment, the material of the second edge structure on the piezoelectric layer and the material of the upper electrode layer may be different.

In this embodiment, the thickness of the edge structure 1109 is greater than the thickness of the electrode layer 1108. In another embodiment, a thickness of the second edge structure on the piezoelectric layer is less than a thickness of the upper electrode layer. In another embodiment, a thickness of the second edge structure on the piezoelectric layer is equal to a thickness of the upper electrode layer.

In this embodiment, the peripheral portion 1106a is located in the resonant region 1112, the peripheral portion 1109a is located in the resonant region 1112, and the peripheral portion 1106a and the peripheral portion 1109a are overlapped to form a peripheral edge of the resonant region 1112. The acoustic impedance of the edge portion 1113 in the resonance region 1112 is higher than that of the intermediate portion 1114 in the resonance region 1112, and the acoustic impedance of the edge portion 1113 is higher than that of the non-resonance region, so that the acoustic wave of the transverse mode is reflected at the horizontal edge of the resonance region 1112 and remains in the resonance region 1112, thereby increasing the Q value.

In this embodiment, the inner side of the peripheral portion 1106a is a straight surface, and the inner side of the peripheral portion 1109a is a straight surface. In another embodiment, the inner side of the peripheral edge portion may be a sloping surface.

In this embodiment, the cavity 1103 is located inside the side cavity 1110, and the cavity 1103 is also located inside the side cavity 1111. In this embodiment, the rim structure 1109 is located above the side cavity 1110, and has an overlapping portion with the side cavity 1110; the edge structure 1106 is located on the side cavity 1111 with an overlap with the side cavity 1111.

It should be noted that the acoustic impedance of the vacuum state or air in the side cavity 1110 is smaller than that of the piezoelectric layer 1107, the acoustic impedance of the vacuum state or air in the side cavity 1111 is smaller than that of the edge structure 1106, and the acoustic wave of the transverse mode is reflected at the boundary between the side cavity 1110 and the piezoelectric layer 1107 and the boundary between the side cavity 1111 and the edge structure 1106, so that the leakage wave propagating towards the middle layer 1102 in the transverse mode is blocked, and the Q value is raised.

In summary, in the bulk acoustic wave resonator device provided in the embodiments of the present invention, a shallow side cavity is disposed beside at least one side of the cavity, an acoustic impedance of vacuum or air in the side cavity is not matched with an acoustic impedance of the piezoelectric layer, the electrode layer, or the edge structure (i.e., an acoustic impedance is different), and a transverse acoustic wave is reflected at a boundary between the piezoelectric layer, the electrode layer, or the edge structure and the side cavity, so as to block a leakage wave propagating in a transverse mode toward the support layer (e.g., the substrate, the intermediate layer), and improve the Q value.

It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims.

Claims

1. A bulk acoustic wave resonator device, comprising:

a first layer comprising a cavity;

a first electrode layer, at least one end of the first electrode layer being located within the cavity;

the piezoelectric layer is positioned on the first electrode layer along the vertical direction and covers the cavity, the piezoelectric layer comprises a first side and a second side opposite to the first side along the vertical direction, and the first electrode layer is positioned on the first side;

the second electrode layer is positioned on the second side and positioned on the piezoelectric layer along the vertical direction, and the overlapped area of the first electrode layer, the second electrode layer and the piezoelectric layer is a first area; and

at least one side cavity is positioned between the first layer and the piezoelectric layer, embedded in the first layer and communicated with the cavity, the depth of the at least one side cavity is smaller than that of the cavity, and the at least one side cavity is positioned outside the first area along the horizontal direction.

2. The bulk acoustic wave resonator device of claim 1, wherein the at least one side cavity comprises: and a first side cavity located outside the first region in the horizontal direction, contacting the piezoelectric layer, and having an overlapping portion with the second electrode layer.

3. The bulk acoustic wave resonator device of claim 1, wherein the at least one side cavity comprises: and a second side cavity located outside the first region in the horizontal direction, located between the first layer and the first electrode layer, contacting the first electrode layer, and having an overlapping portion with the first electrode layer.

4. The bulk acoustic wave resonator device of claim 1, further comprising: and at least one edge structure located at an edge of an overlapping portion of the first electrode layer and the second electrode layer.

5. The bulk acoustic wave resonator device of claim 4, wherein the at least one edge structure comprises: and the first edge structure is positioned on the second side and positioned on the second electrode layer, wherein the first edge structure comprises a first peripheral part, and the first peripheral part is positioned on the edge of the second electrode layer, which is overlapped with the first electrode layer.

6. The bulk acoustic wave resonator device of claim 5, wherein the first peripheral portion is annular.

7. The bulk acoustic wave resonator device of claim 5, wherein the material of the first edge structure comprises a metal.

8. The bulk acoustic wave resonator device of claim 4, wherein the at least one edge structure comprises: and the first electrode layer is positioned on the second edge structure, the second edge structure comprises a second peripheral part, and the second peripheral part is positioned in the cavity and positioned on the edge of the superposition part of the first electrode layer and the second electrode layer.

9. The bulk acoustic wave resonator device of claim 8, wherein the second peripheral portion is annular.

10. The bulk acoustic wave resonator device of claim 8, wherein the material of the second edge structure comprises a metal.

11. The bulk acoustic wave resonator device of claim 8, wherein the at least one side cavity comprises: and the third side cavity is positioned outside the first area along the horizontal direction, positioned between the first layer and the second edge structure, contacts the second edge structure and has an overlapped part with the second edge structure.

12. The bulk acoustic wave resonator device of claim 4, wherein the at least one edge structure comprises: and the third edge structure is positioned on the second side and on the second electrode layer, wherein the third edge structure comprises a third surrounding part, and the third surrounding part is positioned on the second electrode layer and on the partial edge of the first electrode layer superposition part.

13. The bulk acoustic wave resonator device of claim 12, wherein the at least one edge structure further comprises: and the first electrode layer is positioned on the fourth edge structure, the fourth edge structure comprises a fourth surrounding part, and the fourth surrounding part is positioned in the cavity and positioned on the first electrode layer and the partial edge of the superposition part of the second electrode layer.

14. The bulk acoustic wave resonator device of claim 13, wherein the third peripheral portion and the fourth peripheral portion partially overlap to form an annular peripheral edge.

15. The bulk acoustic wave resonator device of claim 13, wherein the material of the third edge structure comprises a metal and the material of the fourth edge structure comprises a metal.

16. The bulk acoustic wave resonator device of claim 13, wherein the at least one side cavity comprises: and the fourth side cavity is positioned outside the first area along the horizontal direction, positioned between the first layer and the fourth edge structure, contacted with the fourth edge structure and provided with an overlapped part with the fourth edge structure.

17. The bulk acoustic wave resonator device of claim 4, wherein the at least one edge structure comprises: and a fifth edge structure located on the second side and on the piezoelectric layer, wherein the fifth edge structure includes a fifth peripheral portion, the second electrode layer is located inside the fifth peripheral portion, the fifth peripheral portion is overlapped with the first electrode layer, and an overlapped portion of the second electrode layer and the first electrode layer is the second electrode layer.

18. The bulk acoustic wave resonator device of claim 17, wherein the fifth peripheral portion is annular.

19. The bulk acoustic wave resonator device of claim 17, wherein the material of the fifth edge structure comprises a metal.

20. The bulk acoustic wave resonator device of claim 17, wherein the at least one side cavity comprises: a fifth side cavity outside the first area along the horizontal direction, contacting the piezoelectric layer, having an overlap with the fifth edge structure.

21. The bulk acoustic wave resonator device of claim 4, wherein the at least one edge structure comprises a sixth edge structure located on the first side, the piezoelectric layer further located on the sixth edge structure, the sixth edge structure comprising a sixth peripheral portion located within the cavity, the first electrode layer located inside the sixth peripheral portion, the sixth peripheral portion coinciding with the second electrode layer, wherein the first electrode layer is located on the first electrode layer at the intersection with the second electrode layer.

22. The bulk acoustic wave resonator device of claim 21, wherein the sixth peripheral portion is annular.

23. The bulk acoustic wave resonator device of claim 21, wherein the material of the sixth edge structure comprises a metal.

24. The bulk acoustic wave resonator device of claim 21, wherein the at least one side cavity comprises: and the sixth side cavity is positioned outside the first area along the horizontal direction, positioned between the first layer and the sixth edge structure, contacted with the sixth edge structure and provided with an overlapped part with the sixth edge structure.

25. The bulk acoustic wave resonator device of claim 4, wherein the at least one edge structure comprises a seventh edge structure on the second side on the piezoelectric layer, the seventh edge structure comprising a seventh peripheral portion at a partial edge of the second electrode layer that coincides with the first electrode layer.

26. The bulk acoustic wave resonator device of claim 25, wherein the at least one side cavity comprises: a seventh side cavity outside the first region in the horizontal direction, contacting the piezoelectric layer, and having an overlap with the seventh edge structure.

27. The bulk acoustic wave resonator device of claim 25, wherein the at least one edge structure further comprises an eighth edge structure located on the first side, the piezoelectric layer further located on the eighth edge structure, the eighth edge structure comprising an eighth peripheral portion located within the cavity at a portion of an edge of the first electrode layer that coincides with the second electrode layer.

28. The bulk acoustic wave resonator device of claim 27, wherein the eighth peripheral portion and the seventh peripheral portion partially overlap to form an annular peripheral edge.

29. The bulk acoustic wave resonator device of claim 27, wherein the material of the seventh edge structure comprises a metal and the material of the eighth edge structure comprises a metal.

30. The bulk acoustic wave resonator device of claim 27, wherein the at least one side cavity comprises: and the eighth side cavity is positioned outside the first area along the horizontal direction, positioned between the first layer and the eighth edge structure, contacted with the eighth edge structure, and provided with a superposition part with the eighth edge structure.

31. The bulk acoustic wave resonator device of claim 1, wherein the first layer comprises: an intermediate layer comprising the cavity, wherein a material of the intermediate layer comprises at least one of: polymer, insulating dielectric, polysilicon.

32. The bulk acoustic wave resonator device of claim 31, wherein the at least one side cavity is located between the intermediate layer and the piezoelectric layer, embedded in the intermediate layer.

33. A filtering apparatus, comprising: at least one bulk acoustic wave resonator device as claimed in any one of claims 1 to 32.

34. A radio frequency front end device, comprising: power amplifying means and at least one filtering means according to claim 33; the power amplifying device is connected with the filtering device.

35. A radio frequency front end device, comprising: low noise amplifying means and at least one filtering means according to claim 33; the low-noise amplifying device is connected with the filtering device.

36. A radio frequency front end device, comprising: multiplexing device comprising at least one filtering device according to claim 33.