CN115580255A - Bulk acoustic wave resonator device, forming method thereof, filter device and radio frequency front end device - Google Patents
Bulk acoustic wave resonator device, forming method thereof, filter device and radio frequency front end device Download PDFInfo
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- H—ELECTRICITY
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- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
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- H—ELECTRICITY
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- H03H9/02—Details
- H03H9/05—Holders; Supports
- H03H9/0504—Holders; Supports for bulk acoustic wave devices
- H03H9/0514—Holders; Supports for bulk acoustic wave devices consisting of mounting pads or bumps
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
- H03H2003/023—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks the resonators or networks being of the membrane type
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Abstract
A bulk acoustic wave resonator device and a forming method thereof, a filter device and a radio frequency front end device are provided, wherein the bulk acoustic wave resonator device comprises: a cavity; at least one end of the first electrode layer is positioned above or in the cavity; the piezoelectric layer, the cavity and the first electrode layer are positioned on the first side of the piezoelectric layer; the second electrode layer is positioned on the second side; the first passive structure is positioned on the first side and provided with a first superposition part with at least one edge of the first electrode layer; the second passive structure is positioned on the second side and provided with a second overlapping part with at least one edge of the second electrode layer; the first passive structure includes: a first raised part located inside the resonance region; the first extending part is positioned outside the resonance area, and the first lifting part is raised relative to the first extending part; wherein the second passive structure comprises: a second raised part at the harmonicThe inner side of the vibration area; and the second extending part is positioned outside the resonance area, and the second lifting part is raised relative to the second extending part. The invention inhibits the parasitic edge mode and promotes Z p And corresponding Q values.
Description
Technical Field
The invention relates to the technical field of semiconductors, in particular to a bulk acoustic wave resonance device, a forming method thereof, 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 (PA), an antenna switch, an RF filter, a multiplexer (multiplexer) including a duplexer (duplexer), and a Low Noise Amplifier (LNA), etc. 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 SAW resonator and the BAW resonator have high quality factor values (Q values), and are made into RF filters with low insertion loss (insertion loss) and high out-of-band rejection (out-band rejection), namely SAW filters and BAW filters, which are mainstream RF filters used in wireless communication equipment 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 frequency of use of the SAW filter is generally from 0.4GHz to 2.7GHz and the frequency of use of the BAW filter is generally from 0.7GHz to 7GHz.
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 advent of the 5G era, higher communication frequency bands are introduced into wireless mobile networks, and currently, only BAW technology can solve the filtering problem of high frequency bands.
Fig. 1 shows a circuit of a BAW filter, comprising a ladder circuit consisting of a plurality of BAW resonators, a first end of the circuit being connected to a transceiving end and a second end of the circuit being connected to an antenna, wherein f1, f2, f3, f4 respectively represent 4 different frequencies. In each BAW resonator, metal electrodes on two sides of a piezoelectric layer of the resonator generate alternative positive and negative voltages, the piezoelectric layer generates acoustic waves through the alternative positive and negative voltages, and the acoustic waves in the resonator vertically propagate along the thickness direction of 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 of the reflection of the sound wave is that the acoustic impedance of the contact area between the upper surface of the upper metal electrode and the lower surface of the lower metal electrode is different from the acoustic impedance of the metal electrode.
The performance of an RF filter depends on the performance of the resonator, which is determined by the minimum series impedance (Z) of the resonator s Maximum parallel impedance (parallel impedance) Z p And an electromechanical coupling coefficient (Kt) 2 Isoparametric representation in which Z s And Z p Representing electrical losses in the resonator, such as thermal losses, acoustic losses, etc. The resonator operating at the series resonance frequency f s When the input impedance reaches a minimum value of Z s (ii) a The resonator operating at a parallel resonant frequency f p When the input impedance reaches a maximum value of Z p . Electromechanical coupling coefficient Kt 2 Represents Z s And Z p The frequency difference between them, affects the passband (passband) bandwidth of the RF filter. With a higher Kt 2 Or Z p And lower Z s The performance of the resonator of (2) is better. Those skilled in the art will recognize that resonator design requirements at Kt are 2 And Z p By taking a trade-off between, i.e. raising Kt 2 At the same time, Z is reduced p Lifting of Z p While lowering Kt 2 。
A Film Bulk Acoustic Wave Resonator (FBAR) is a BAW Resonator which can confine Acoustic energy in a device, and a resonant area of the BAW Resonator is vacuum or air above the FBAR Resonator, and a cavity exists below the FBAR Resonator.
Fig. 2 shows a schematic structure of an FBAR 200. The FBAR 200 includes:a substrate 201; a cavity 203 embedded in the substrate 201; a first electrode layer 205 (i.e., a lower electrode layer) on the substrate 201 and the cavity 203, covering the cavity 203; a piezoelectric layer 207 on said first electrode layer 205; and a second electrode layer 209 (i.e., an upper electrode layer) on the piezoelectric layer 207; the overlapping region of the first electrode layer 205, the piezoelectric layer 207, and the second electrode layer 209 is a resonance region of the FBAR 200. Two sets of acoustic waves are generated in the resonance region, the first set of acoustic waves includes a compression wave (longitudinal wave) and a shear wave (shear wave) which propagate in a direction perpendicular to the piezoelectric layer 207, the second set of acoustic waves includes an acoustic wave (RL wave) which propagates towards the lateral edge of the piezoelectric layer 207, propagates along the lateral surfaces of the two electrode layers to the lateral edge of the piezoelectric layer 207, and a parasitic edge mode (parasitic resonance) is generated by excitation at the edge, so that the Z resonance is reduced p And the corresponding Q value.
Disclosure of Invention
The invention provides a bulk acoustic wave resonance device, a forming method thereof, a filtering device and a radio frequency front end device, which can attenuate transversely-propagated acoustic waves generated in a resonance area, inhibit parasitic edge modes and improve Z p And corresponding Q value, while for Kt 2 Has a smaller influence.
In order to solve the above problems, a technical solution of the present invention provides a bulk acoustic wave resonator device, including: a cavity; a first electrode layer, at least one end of the first electrode layer being located above the cavity or within the cavity; the piezoelectric layer comprises a first side and a second side opposite to the first side in the vertical direction, the cavity is located on the first side, the first electrode layer is located on the first side, and the first electrode layer is in contact with the piezoelectric layer; the second electrode layer is positioned on the second side and is in contact with the piezoelectric layer, and the overlapped area of the first electrode layer, the second electrode layer and the piezoelectric layer is a resonance area; a first passive structure located on the first side and having a first overlap with at least one edge of the first electrode layer; a second passive structure located on the second side and having a second overlap with at least one edge of the second electrode layer; wherein the first passive structure comprises: a first raised portion located inside the resonance region and having the first overlapping portion with at least one edge of the first electrode layer, the first raised portion being configured to match acoustic impedances of the resonance region and at least one attenuation region outside the resonance region, so that more of the sound waves generated in the resonance region enter the at least one attenuation region; a first dielectric portion between the first raised portion and the first electrode layer for electrically isolating the first electrode layer from the first passive structure; a first extension portion located outside the resonance region and inside the at least one attenuation region for attenuating the sound waves entering the at least one attenuation region, the first raised portion being raised with respect to the first extension portion; the second passive structure includes: a second raised portion located inside the resonance region and having a second overlap portion with at least one edge of the second electrode layer, the second raised portion being configured to match acoustic impedances of the resonance region and the at least one attenuation region, so that more of the sound waves generated in the resonance region enter the at least one attenuation region; a second dielectric portion between the second raised portion and the second electrode layer for electrically isolating the second electrode layer from the second passive structure; the second extending portion is located outside the resonance region and inside the at least one attenuation region and used for attenuating the sound waves entering the at least one attenuation region, and the second lifting portion is convex relative to the second extending portion.
Optionally, the first passive structure and the second passive structure surround the resonance region.
Optionally, a thickness of the first passive structure is equal to or less than a thickness of the first electrode layer, and a thickness of the second passive structure is equal to or less than a thickness of the second electrode layer.
Optionally, at least one of the attenuation regions includes a first attenuation region, a first cutoff frequency of the first attenuation region is equal to or lower than a cutoff frequency of the resonance region, and the first attenuation region corresponds to a region where the first extension portion, the piezoelectric layer and the second extension portion coincide.
Optionally, the method further includes: a first electrode extension layer located at the first side and connected with the first electrode layer; a second electrode extension layer on the second side, connected to the second electrode layer.
Optionally, at least one of the attenuation regions includes a second attenuation region, a second cutoff frequency of the second attenuation region is equal to or lower than a cutoff frequency of the resonance region, and the second attenuation region corresponds to a region where the second electrode extension layer, the piezoelectric layer, and the first extension portion overlap.
Optionally, at least one of the attenuation regions includes a third attenuation region, a third cutoff frequency of the third attenuation region is equal to or lower than a cutoff frequency of the resonance region, and the third attenuation region corresponds to a region where the second extension portion, the piezoelectric layer, and the first electrode extension layer overlap.
Optionally, at least one edge of the first electrode layer is in a downslope shape corresponding to the first passive structure, and at least one edge of the second electrode layer is in a downslope shape corresponding to the second passive structure.
Optionally, the width of the first raised part is an integral multiple of one-half wavelength of the sound wave generated in the resonance region, and the width of the second raised part is an integral multiple of one-half wavelength of the sound wave generated in the resonance region.
Optionally, a thickness of the first extension portion is smaller than a thickness of the first electrode layer, and a thickness of the second extension portion is smaller than a thickness of the second electrode layer.
Optionally, the first extending portion includes a first sub-portion and a second sub-portion, the second sub-portion and the piezoelectric layer are located on two sides of the first sub-portion, and a material of the first sub-portion is different from a material of the second sub-portion.
Optionally, the second extending portion includes a third sub-portion and a fourth sub-portion, the piezoelectric layer and the fourth sub-portion are located on two sides of the third sub-portion, and a material of the third sub-portion is different from a material of the fourth sub-portion.
Optionally, the first extension contacts the piezoelectric layer and the second extension contacts the piezoelectric layer.
Optionally, the first dielectric portion is further located between the piezoelectric layer and the first extension portion, and the second dielectric portion is further located between the piezoelectric layer and the second extension portion.
Optionally, a first empty groove is included between the first extending portion and the piezoelectric layer, and a second empty groove is included between the piezoelectric layer and the second extending portion.
Optionally, the method further includes: a third dielectric portion on the second side and in contact with the second electrode layer; a surrounding type groove located in the third dielectric portion, located inside the resonance region, located inside the second raised portion, and adjacent to the second raised portion.
Optionally, the shape of the surrounding groove includes: circular, elliptical, or polygonal.
Optionally, the method further includes: a third dielectric portion on the first side and in contact with the first electrode layer; a surrounding type groove located in the third dielectric portion, located inside the resonance region, located inside the first raised portion, and adjacent to the first raised portion.
Optionally, the shape of the surrounding groove includes: circular, elliptical, or polygonal.
Correspondingly, the technical solution of the present invention further provides a filtering apparatus, including: at least one bulk acoustic wave resonator device as described in one of the above.
Correspondingly, the technical solution of the present invention further provides a radio frequency front end device, including: a power amplifying device and at least one filtering device as described above; the power amplifying device is connected with the filtering device.
Correspondingly, the technical solution of the present invention further provides a radio frequency front end device, which is characterized by comprising: low noise amplification means and at least one filtering means as described in one of the above; the low-noise amplifying device is connected with the filtering device.
Correspondingly, the technical solution of the present invention further provides a radio frequency front end device, which is characterized by comprising: multiplexing means comprising at least one filtering means as described in one of the above.
Correspondingly, the technical scheme of the invention also provides a method for forming the bulk acoustic wave resonance device, which comprises the following steps: forming a piezoelectric layer including a first side and a second side opposite the first side in a vertical direction; forming a first electrode layer on the first side contacting the piezoelectric layer; forming a second electrode layer, wherein the second electrode layer is positioned on the second side and contacts the piezoelectric layer, and the superposed area of the first electrode layer, the second electrode layer and the piezoelectric layer is a resonance area; forming a first passive structure on the first side, wherein the first passive structure and at least one edge of the first electrode layer have a first superposition part; wherein the first passive structure comprises: the first lifting part is raised relative to the first extending part; the first lifting part is positioned on the inner side of the resonance region, the first lifting part and at least one edge of the first electrode layer are provided with the first superposition part, and the first lifting part is used for matching acoustic impedances of the resonance region and at least one attenuation region on the outer side of the resonance region so that more sound waves generated in the resonance region enter the at least one attenuation region; the first dielectric portion is located between the first raised portion and the first electrode layer for electrically isolating the first electrode layer from the first passive structure; the first extension part is positioned outside the resonance region and in at least one attenuation region and is used for attenuating sound waves entering the at least one attenuation region; forming a second passive structure on the second side having a second overlap with at least one edge of the second electrode layer, wherein the second passive structure comprises: the second lifting part is raised relative to the second extending part; the second uplift part is positioned on the inner side of the resonance region, the second uplift part and at least one edge of the second electrode layer are provided with the second overlapping part, and the second uplift part is used for matching the acoustic impedance of the resonance region and at least one attenuation region so that more sound waves generated in the resonance region enter at least one attenuation region; the second dielectric portion is located between the second raised portion and the second electrode layer for electrically isolating the second electrode layer from the second passive structure; the second extension portion is located outside the resonance region and inside the at least one attenuation region, and is used for attenuating the sound wave entering the at least one attenuation region.
Optionally, the first passive structure and the second passive structure surround the resonance region.
Optionally, a thickness of the first passive structure is equal to or less than a thickness of the first electrode layer, and a thickness of the second passive structure is equal to or less than a thickness of the second electrode layer.
Optionally, forming the first electrode layer includes forming at least one downward-sloping edge corresponding to the first passive structure, and forming the second electrode layer includes forming at least one downward-sloping edge corresponding to the second passive structure.
Optionally, forming the first passive structure includes forming a first passivation layer on the first side to cover the first electrode layer; forming a first lapping layer which contacts the first passivation layer, wherein at least one edge of the first lapping layer and at least one edge of the first electrode layer are provided with the first superposition part; wherein the first passivation layer includes the first dielectric portion; wherein the first lap layer comprises the first raised part and the first extending part.
Optionally, forming the second passive structure includes forming a second passivation layer on the second side to cover the second electrode layer; forming a second overlap layer contacting the second passivation layer, wherein at least one edge of the second overlap layer and the second electrode layer has the second overlapping portion; wherein the second passivation layer comprises the second dielectric portion; wherein the second lap layer includes the second raised portion and the second extending portion.
Optionally, a thickness of the first extension portion is smaller than a thickness of the first electrode layer, and a thickness of the second extension portion is smaller than a thickness of the second electrode layer.
Optionally, at least one of the attenuation regions includes a first attenuation region, a first cutoff frequency of the first attenuation region is equal to or lower than a cutoff frequency of the resonance region, and the first attenuation region corresponds to a region where the first extension portion, the piezoelectric layer and the second extension portion coincide.
Optionally, the method further includes: forming a first electrode extension layer positioned on the first side and connected with the first electrode layer; and forming a second electrode extension layer which is positioned on the second side and is connected with the second electrode layer.
Optionally, at least one of the attenuation regions includes a second attenuation region, a second cutoff frequency of the second attenuation region is equal to or lower than a cutoff frequency of the resonance region, and the second attenuation region corresponds to a region where the second electrode extension layer, the piezoelectric layer, and the first extension portion overlap.
Optionally, at least one of the attenuation regions includes a third attenuation region, a third cutoff frequency of the third attenuation region is equal to or lower than a cutoff frequency of the resonance region, and the third attenuation region corresponds to a region where the second extension portion, the piezoelectric layer, and the first electrode extension layer overlap.
Optionally, the width of the first raised part is an integral multiple of one-half wavelength of the sound wave generated in the resonance region, and the width of the second raised part is an integral multiple of one-half wavelength of the sound wave generated in the resonance region.
Optionally, forming the first overlap layer includes; forming a first butt-strap sublayer and a second butt-strap sublayer, wherein the second butt-strap sublayer and the piezoelectric layer are positioned on two sides of the first butt-strap sublayer, and the material of the first butt-strap sublayer is different from that of the second butt-strap sublayer.
Optionally, forming the second overlap layer includes; and forming a third overlap sub-layer and a fourth overlap sub-layer, wherein the fourth overlap sub-layer and the piezoelectric layer are positioned at two sides of the third overlap sub-layer, and the material of the third overlap sub-layer is different from that of the fourth overlap sub-layer.
Optionally, the method further includes: forming a first sacrificial layer between the first extension and the piezoelectric layer; forming a second sacrificial layer between the second extension and the piezoelectric layer.
Optionally, the method further includes: removing the first sacrificial layer to form a first empty groove located between the first extending portion and the piezoelectric layer; and removing the second sacrificial layer to form a second empty groove which is positioned between the second extending part and the piezoelectric layer.
Optionally, the first dielectric part is further located between the piezoelectric layer and the first extension part, and the second dielectric part is further located between the piezoelectric layer and the second extension part.
Optionally, the method further includes: forming a third dielectric portion on the second side and in contact with the second electrode layer; forming a surrounding type groove in the third dielectric portion, inside the resonance region, inside the second raised portion, and adjacent to the second raised portion.
Optionally, the shape of the surrounding groove includes: circular, elliptical, or polygonal.
Optionally, the method further includes: forming a third dielectric portion on the first side and in contact with the first electrode layer; forming a surrounding type groove in the third dielectric portion, inside the resonance region, inside the first raised portion, and adjacent to the first raised portion.
Optionally, the shape of the surrounding groove includes: circular, elliptical, or polygonal.
Compared with the prior art, the technical scheme of the invention has the following advantages:
in the bulk acoustic wave resonator device according to the aspect of the present invention, the first raised portion of the first passive structure is located inside the resonance region and has an overlapping portion with the first electrode layer, the second raised portion of the second passive structure is located inside the resonance region and has an overlapping portion with the second electrode layer, and acoustic impedances of the resonance region and an attenuation region (evaporative region) outside the resonance region can be matched, so that a large amount of acoustic waves generated in the resonance region are propagated into the resonance regionThe attenuation region. In addition, the cutoff frequency (cutoff frequency) of the attenuation region is matched with (e.g., equal to or less than) the cutoff frequency of the resonance region, so that the sound wave entering the attenuation region can be attenuated, parasitic edge modes can be suppressed, and the Z can be improved p And corresponding Q values. The cutoff frequency is a frequency corresponding to a wave number (wave number) of 0 on a dispersion curve (dispersion curve). Furthermore, the first passive structure is not electrically connected to the first electrode layer and the second passive structure is not electrically connected to the second electrode layer, so that the first passive structure and the second passive structure pair Kt 2 Is small so that the performance of a filtering apparatus comprising the bulk acoustic wave resonator device, e.g. insertion loss, out-of-band rejection, can be improved.
Further, still include: a third dielectric portion in contact with the electrode layer; and a surrounding type groove located in the third dielectric portion, located inside the resonance region, located inside the raised portion, and adjacent to the raised portion. The surrounding groove, a first section area formed by the surrounding groove and a second section area formed by the lifting part are additionally arranged at the inner side of the resonance area. The cutoff frequency of the first section region is set to be higher than the cutoff frequency of the middle part of the resonance region inside the surrounding groove, the cutoff frequency of the second section region is set to be lower than the cutoff frequency of the middle part, a piston mode (piston mode) is formed, the higher order parasitic mode of transverse sound waves is suppressed, and the series resonance frequency (f) is reduced s ) Near and less than f s Clutter of the portion (c).
In the method for forming a bulk acoustic wave resonator device according to the aspect of the present invention, the first raised portion of the first passive structure is formed inside the resonance region, and has an overlap portion with the first electrode layer, the second raised portion of the second passive structure is formed inside the resonance region, and has an overlap portion with the second electrode layer, and the acoustic impedances of the resonance region and an attenuation region (evaporative region) outside the resonance region can be matched, so that a large amount of acoustic waves generated in the resonance region propagate into the attenuation region. Further, a cutoff frequency (cutoff frequency) of the attenuation region matches (e.g., is equal to or less than) the harmonicThe cut-off frequency of the vibration area can attenuate the sound wave entering the attenuation area, inhibit the parasitic edge mode and improve the Z p And corresponding Q values. The cutoff frequency is a frequency corresponding to a wave number (wave number) of 0 on a dispersion curve (dispersion curve). Furthermore, the first passive structure is not electrically connected to the first electrode layer and the second passive structure is not electrically connected to the second electrode layer, so that the first passive structure and the second passive structure pair Kt 2 So that the performance of the filtering means comprising the bulk acoustic wave resonator device, e.g. insertion loss, out-of-band rejection, can be improved.
Further, still include: forming a third dielectric portion in contact with the electrode layer; and forming a surrounding type groove, located in the third dielectric portion, located inside the resonance region, located inside the raised portion, and adjacent to the raised portion. The surrounding groove, a first section area formed by the surrounding groove and a second section area formed by the lifting part are additionally arranged on the inner side of the resonance area. The cutoff frequency of the first section region is set to be higher than the cutoff frequency of the middle part of the resonance region inside the surrounding groove, the cutoff frequency of the second section region is set to be lower than the cutoff frequency of the middle part, a piston mode (piston mode) is formed, the higher order parasitic mode of transverse sound waves is suppressed, and the series resonance frequency (f) is reduced s ) Near and less than f s Clutter of the portion (c).
Drawings
Fig. 1 is a schematic diagram of a bulk acoustic wave filter circuit;
fig. 2 is a schematic structural diagram of an FBAR 200;
fig. 3 to 6 are schematic structural diagrams of a bulk acoustic wave resonator 3000 according to an embodiment of the present invention;
FIG. 7 is a schematic structural diagram of a hexagonal crystal grain;
FIG. 8 (i) is a schematic diagram of an orthorhombic crystal grain structure;
FIG. 8 (ii) is a schematic structural diagram of a tetragonal crystal grain;
FIG. 8 (iii) is a schematic structural view of a cubic crystal grain;
fig. 9 is a schematic view of an acoustic dispersion curve 600 of a bulk acoustic wave resonator device according to an embodiment of the present invention;
FIG. 10 is a schematic diagram of a parallel impedance curve 700 for a bulk acoustic wave resonator device in accordance with an embodiment of the present invention;
fig. 11 to 14 are schematic structural diagrams of a bulk acoustic wave resonator 3000 according to an embodiment of the present invention, where fig. 11 is a schematic structural diagram of a first cross section of the bulk acoustic wave resonator 3000 and a schematic sound velocity distribution diagram of a corresponding region;
fig. 15 is a schematic view of a sound wave dispersion curve of a bulk acoustic wave resonator device according to an embodiment of the present invention;
fig. 16 is a first schematic cross-sectional structure diagram of a bulk acoustic wave resonator device 3000 according to another embodiment of the present invention and a sound velocity distribution diagram of a corresponding region;
fig. 17 to 18 are schematic structural views of a bulk acoustic wave resonator device 8000 according to an embodiment of the present invention;
fig. 19 is a schematic diagram of a wireless communication device 900;
FIG. 20 is a flow chart illustrating a method 1000 of forming a bulk acoustic wave resonator device in accordance with an embodiment of the present invention;
fig. 21 to 24 are schematic structural diagrams of a cross section a of a method for forming a bulk acoustic wave resonator device 1100 according to an embodiment of the present invention;
fig. 25 is a schematic diagram of a structure of a cross section a of a method for forming a bulk acoustic wave resonator device 1100 according to another embodiment of the present invention and a sound velocity distribution diagram of a corresponding region;
fig. 26 and 27 are schematic structural diagrams of a section a of a method for forming a bulk acoustic wave resonator device 1100 according to yet another embodiment of the present invention, where fig. 27 is a schematic structural diagram of a first cross section of the bulk acoustic wave resonator device 1100 and a schematic sound velocity distribution diagram of a corresponding region;
fig. 28 to fig. 31 are schematic structural diagrams of a cross section a of a method for forming a bulk acoustic wave resonator 1200 according to an embodiment of the present invention;
FIG. 32 is a graph comparing two series admittance curves.
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, the acoustic wave generated in the resonance region propagates to the lateral edges of the piezoelectric layer along the side surfaces of the two electrode layers, and excites a parasitic edge mode at the edges to generate a parasitic resonance, thereby lowering Z p And corresponding Q values.
The inventors of the present invention have found that the raised portion of the passive structure is located inside the resonance region and has an overlap with the electrode layer, so that the acoustic impedances of the resonance region and the attenuation region outside the resonance region can be matched, and more of the acoustic waves generated by the resonance region propagate into the attenuation region. In addition, the cutoff frequency of the attenuation region matches (e.g., is equal to or less than) the cutoff frequency of the resonance region, which can attenuate sound waves entering the attenuation region, suppress parasitic edge modes, and raise Z p And the corresponding Q value. Furthermore, the passive structures are not electrically connected to the electrode layers, so that the passive structure pairs Kt 2 Has a smaller influence.
To solve the above problem, an embodiment of the present invention provides a bulk acoustic wave resonator device, including: a cavity; a first electrode layer, at least one end of the first electrode layer being located above the cavity or within the cavity; the piezoelectric layer comprises a first side and a second side opposite to the first side in the vertical direction, the cavity is located on the first side, the first electrode layer is located on the first side, and the first electrode layer is in contact with the piezoelectric layer; the second electrode layer is positioned on the second side and is in contact with the piezoelectric layer, and the overlapped area of the first electrode layer, the second electrode layer and the piezoelectric layer is a resonance area; a first passive structure located on the first side and having a first overlapping portion with at least one edge of the first electrode layer; a second passive structure located on the second side and having a second overlap with at least one edge of the second electrode layer;
wherein the first passive structure comprises: a first raised portion located inside the resonance region and having the first overlapping portion with at least one edge of the first electrode layer, the first raised portion being configured to match acoustic impedances of the resonance region and at least one attenuation region outside the resonance region, so that more of the sound waves generated in the resonance region enter the at least one attenuation region; a first dielectric portion between the first raised portion and the first electrode layer for electrically isolating the first electrode layer from the first passive structure; a first extension located outside the resonance region and within the at least one attenuation region for attenuating sound waves entering the at least one attenuation region, the first lift portion being raised relative to the first extension;
wherein the second passive structure comprises: a second raised portion located inside the resonance region and having a second overlap portion with at least one edge of the second electrode layer, the second raised portion being configured to match acoustic impedances of the resonance region and the at least one attenuation region, so that more of the sound waves generated in the resonance region enter the at least one attenuation region; a second dielectric portion between the second raised portion and the second electrode layer for electrically isolating the second electrode layer from the second passive structure; and the second extension part is positioned outside the resonance region and in the at least one attenuation region and is used for attenuating the sound waves entering the at least one attenuation region, and the second lifting part is raised relative to the second extension part.
In some embodiments, the first passive structure and the second passive structure surround the resonance region.
In some embodiments, the first passive structure has a thickness equal to or less than a thickness of the first electrode layer, and the second passive structure has a thickness equal to or less than a thickness of the second electrode layer.
In some embodiments, the at least one attenuation region includes a first attenuation region having a first cutoff frequency equal to or less than a cutoff frequency of the resonance region, the first attenuation region corresponding to a region where the first extension, the piezoelectric layer, and the second extension coincide.
In some embodiments, the bulk acoustic wave resonator device further comprises: a first electrode extension layer located at the first side and connected with the first electrode layer; a second electrode extension layer on the second side, connected to the second electrode layer.
In some embodiments, the at least one attenuation region includes a second attenuation region having a second cutoff frequency equal to or less than a cutoff frequency of the resonance region, the second attenuation region corresponding to a region where the second electrode extension layer, the piezoelectric layer, and the first extension portion coincide.
In some embodiments, the at least one attenuation region includes a third attenuation region having a third cutoff frequency equal to or less than the cutoff frequency of the resonance region, the third attenuation region corresponding to a region where the second extension portion, the piezoelectric layer, and the first electrode extension layer coincide.
In some embodiments, at least one edge of the first electrode layer is downslope corresponding to the first passive structure and at least one edge of the second electrode layer is downslope corresponding to the second passive structure.
In some embodiments, the width of the first raised portion is an integer multiple of one-half wavelength of the acoustic waves generated within the resonance region, and the width of the second raised portion is an integer multiple of one-half wavelength of the acoustic waves generated within the resonance region.
In some embodiments, the first extension portion has a thickness less than a thickness of the first electrode layer, and the second extension portion has a thickness less than a thickness of the second electrode layer.
In some embodiments, the first extending portion includes a first sub-portion and a second sub-portion, the second sub-portion and the piezoelectric layer are located on two sides of the first sub-portion, and a material of the first sub-portion is different from a material of the second sub-portion.
In some embodiments, the second extending portion includes a third sub-portion and a fourth sub-portion, the piezoelectric layer and the fourth sub-portion are located on two sides of the third sub-portion, and a material of the third sub-portion is different from a material of the fourth sub-portion.
In some embodiments, the first extension contacts the piezoelectric layer and the second extension contacts the piezoelectric layer.
In some embodiments, the first dielectric portion is further located between the piezoelectric layer and the first extension, and the second dielectric portion is further located between the piezoelectric layer and the second extension.
In some embodiments, a first void is included between the first extension and the piezoelectric layer, and a second void is included between the piezoelectric layer and the second extension.
In some embodiments, further comprising: a third dielectric portion on the second side and in contact with the second electrode layer; a surrounding type groove located in the third dielectric portion, located inside the resonance region, located inside the second raised portion, and adjacent to the second raised portion.
In some embodiments, the shape of the circumferential groove comprises: circular, elliptical, or polygonal.
In some embodiments, further comprising: a third dielectric portion on the first side and in contact with the first electrode layer; a surrounding type groove located in the third dielectric portion, located inside the resonance region, located inside the first raised portion, and adjacent to the first raised portion.
In some embodiments, the shape of the encircling groove comprises: circular, elliptical, or polygonal.
The first raised portion of the first passive structure may be located inside the resonance region and may overlap the first electrode layer, the second raised portion of the second passive structure may be located inside the resonance region and may overlap the second electrode layer, and the attenuation region (evaporative region) may be located outside the resonance region and the resonance regionAcoustic impedance, such that more of the sound waves generated by the resonance region propagate into the attenuation region. In addition, the cutoff frequency (cutoff frequency) of the attenuation region is matched with (e.g., equal to or less than) the cutoff frequency of the resonance region, so that the sound wave entering the attenuation region can be attenuated, parasitic edge modes can be suppressed, and the Z can be improved p And corresponding Q values. The cutoff frequency is a frequency corresponding to a wave number (wave number) of 0 on a dispersion curve (dispersion curve). Furthermore, the first passive structure and the first electrode layer and the second passive structure and the second electrode layer are not electrically connected, so that the first passive structure and the second passive structure pair Kt 2 Is small so that the performance of a filtering apparatus comprising the bulk acoustic wave resonator device, e.g. insertion loss, out-of-band rejection, can be improved.
Fig. 3 through 6 illustrate one embodiment of the bulk acoustic wave resonator device of the present invention, but the present invention may be practiced in other ways than those described herein, and thus the present invention is not limited to the embodiments disclosed below. Wherein, fig. 3 is a first cross-sectional structure diagram of the bulk acoustic wave resonator device, fig. 4 is a second cross-sectional structure diagram of the bulk acoustic wave resonator device, fig. 5 is a first top view structure diagram of the first electrode layer of the bulk acoustic wave resonator device relative to the first cross-section, and fig. 6 is a second top view structure diagram of the second electrode layer of the bulk acoustic wave resonator device relative to the first cross-section.
Fig. 3 is a schematic structural diagram of a cross section a of a bulk acoustic wave resonator 3000 according to an embodiment of the present invention.
As shown in fig. 3, the bulk acoustic wave resonator device 3000 includes: a piezoelectric layer 3001, the piezoelectric layer 3001 including a first side 3002 and a second side 3003 opposite the first side 3002 in a vertical direction; a first electrode layer 3004 on the first side 3002 and contacting the piezoelectric layer 3001, wherein the first electrode layer 3004 includes a first edge and a second edge opposite to the first edge in a horizontal direction, and the first edge is in a down slope shape; a first electrode extension 3005 on the first side 3002, contacting the piezoelectric layer 3001, and connected to the second edge; a second electrode layer 3006 on the second side 3003 and contacting the piezoelectric layer 3001, wherein the second electrode layer 3006 includes a third edge and a fourth edge opposite to the third edge in a horizontal direction, and the fourth edge is in a down slope shape; a second electrode extension layer 3007 on said second side 3003, contacting said piezoelectric layer 3001, connected to said third edge; an overlapping area of the first electrode layer 3004, the second electrode layer 3006, and the piezoelectric layer 3001 is a resonance area 3100, wherein the first edge corresponds to the third edge in a vertical direction, and the second edge corresponds to the fourth edge in the vertical direction; the first electrode extension layer 3005 and the second electrode extension layer 3007 are located outside the resonance region 3100 without an overlapping portion; a first passivation layer 3008 on the first side 3002, the first passivation layer 3008 inside the resonance region 3100 covering the first electrode layer 3004, the first passivation layer 3008 outside the resonance region 3100 covering the piezoelectric layer 3001 outside the first edge and the first electrode extension layer 3005 outside the second edge; a second passivation layer 3009 on the second side 3003, the second passivation layer 3009 on the inner side of the resonance region 3100 covering the second electrode layer 3006, the second passivation layer 3009 on the outer side of the resonance region 3100 covering the second electrode extension layer 3007 on the outer side of the third edge and the piezoelectric layer 3001 on the outer side of the fourth edge; a first overlap layer 3010 on the first side 3002 and contacting the first passivation layer 3008, where the first overlap layer 3010 includes a first raised portion (not labeled) and a first extended portion (not labeled), the first raised portion is raised relative to the first extended portion, the first raised portion is located inside the resonance area 3100 and has an overlap with the first electrode layer 3004 on the first edge side, the first raised portion and the first electrode layer 3004 are located on both sides of the first passivation layer 3008, the first extended portion is located outside the resonance area 3100 and located outside the first edge and has no overlap with the first electrode layer 3004, and the first extended portion and the piezoelectric layer 3001 are located on both sides of the first passivation layer 3008 in a vertical direction; the second overlap layer 3011 is located on the second side 3003 and contacts the second passivation layer 3009, the second overlap layer 3011 includes a second raised portion (not labeled) and a second extended portion (not labeled), the second raised portion is raised relative to the second extended portion, the second raised portion is located inside the resonance area 3100 and has an overlapping portion with the second electrode layer 3006 on the fourth edge side, the second raised portion and the second electrode layer 3006 are located on both sides of the second passivation layer 3009, the second extended portion is located outside the resonance area 3100 and located outside the fourth edge and has no overlapping portion with the second electrode layer 3006, and the second extended portion and the piezoelectric layer 3001 are located on both sides of the second passivation layer 3009 in the vertical direction.
In this embodiment, the material of the piezoelectric layer 3001 includes, but is not limited to, one of the following: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate (PZT), lead magnesium niobate-lead titanate.
In this embodiment, the piezoelectric layer 3001 is a flat layer, and the piezoelectric layer 3001 includes a plurality of crystal grains including a first crystal grain and a second crystal grain, where 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. As shown in fig. 7, 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. 8, crystal grains of (i) orthorhombic system (a ≠ b ≠ c), (ii) tetragonal system (a = b ≠ c), and (iii) cubic system (a = b = c) are expressed by an 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 includes at least a first coordinate axis along a first direction and a third coordinate axis along a third direction, and the second stereo coordinate system includes at least 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, where 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 equally directed.
In this embodiment, the piezoelectric layer 3001 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 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.
In this embodiment, the material of the first electrode layer 3004 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium, and the material of the first electrode extension layer 3005 includes but is not limited to at least one of: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium, copper and gold. In this embodiment, the material of the first electrode layer 3004 is the same as the material of the first electrode extension layer 3005.
In this embodiment, the material of the second electrode layer 3006 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium, and the material of the second electrode extension layer 3007 includes but is not limited to at least one of: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium, copper, gold. In this embodiment, the material of the second electrode layer 3006 is the same as the material of the second electrode extension layer 3007.
In another embodiment, the material of the electrode layer and the material of the electrode extension layer may be different.
In this embodiment, the material of the first passivation layer 3008 includes, but is not limited to, one of the following: silicon dioxide, silicon oxynitride, silicon oxycarbide, silicon nitride, titanium oxide, aluminum oxide, hafnium silicate, zirconium silicate, hafnium dioxide, zirconium dioxide. In this embodiment, the material of the second passivation layer 3009 includes, but is not limited to, one of the following: silicon dioxide, silicon oxynitride, silicon oxycarbide, silicon nitride, titanium oxide, aluminum oxide, hafnium silicate, zirconium silicate, hafnium dioxide, zirconium dioxide. In this embodiment, the material of the first passivation layer 3008 is the same as the material of the second passivation layer 3009. In another embodiment, the material of the first passivation layer (e.g., the first passivation layer 3008) and the material of the second passivation layer (e.g., the second passivation layer 3009) may be different.
In this embodiment, the material of the first lap layer 3010 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 first strap layer 3010 is the same as that of the electrode 3004.
In this embodiment, the material of the second lap layer 3011 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 second strap layer 3011 is the same as the material of the electrode 3006.
In another embodiment, the material of the overlap layer may be different from the material of the electrode layer, for example, the material of the overlap layer is tungsten or platinum, and the material of the electrode layer is molybdenum.
In another embodiment, the bead layer includes a first bead layer and a second bead layer, the first bead layer contacts the passivation layer, the second bead layer contacts the first bead layer, the second bead layer and the passivation layer are located on two sides of the first bead layer, the first bead layer is made of a material different from that of the second bead layer, for example, the first bead layer is made of molybdenum, and the second bead layer is made of platinum or tungsten.
In this embodiment, the bulk acoustic wave resonator 3000 further includes: a first passive structure 3012 on the first side 3002 and contacting the first electrode layer 3004 at a first edge and the piezoelectric layer 3001 outside the first edge, the first passive structure 3012 comprising the first overlap layer 3010 and a first dielectric portion (not labeled) on the first passivation layer 3008 coincident with the first overlap layer 3010; and a second passive structure 3013 on the second side 3003 and contacting the fourth edge of the second electrode layer 3006 and the piezoelectric layer 3001 outside the fourth edge, wherein the second passive structure 3013 includes a second dielectric portion (not labeled) on the second tab layer 3011 and the second passivation layer 3009 and overlapping with the second tab layer 3011. The dielectric portion may electrically isolate the electrode layer and the overlap layer from each other to prevent conduction therebetween, so that the overlap layer is passive, and a combined structure of the dielectric portion and the overlap layer is also passive.
In this embodiment, a first thickness of the first passive structure 3012 is smaller than a thickness of the first electrode layer 3004, a second thickness of the second passive structure 3013 is smaller than a thickness of the second electrode layer 3006, and the first thickness is equal to or approximate to the second thickness.
In this embodiment, the first width of the first raised portion matches a primary mode of transverse acoustic waves generated by the resonance region 3100, such as the rayleigh S1 mode (1) st order systematic mode), or TE1 mode (1) st order Thickness Extension mode), the second width of the second raised portion matching the acoustic wavelength of the fundamental mode of transverse acoustic waves generated by the resonant region 3100 (e.g., the second width equals an integer multiple of one-half wavelength), the first width being equal to or approximately equal to the second width. The first raised portion and the second raised portion are used to match acoustic impedances of the resonance region and the attenuation region, so that more of the sound waves generated by the resonance region propagate into the attenuation region.
In this embodiment, a third thickness of the first extension portion is smaller than a thickness of the first electrode layer 3004, a fourth thickness of the second extension portion is smaller than a thickness of the second electrode layer 3006, and the third thickness is equal to or approximately equal to the fourth thickness.
In this embodiment, an overlapping region of the first extension portion, the second electrode extension layer 3007 and the piezoelectric layer 3001 is an attenuation region 3200; the overlapped area of the second extension portion, the first electrode extension layer 3005 and the piezoelectric layer 3001 is an attenuation region 3300; a first cutoff frequency of the attenuation region 3200 matches (e.g., is equal to or less than) a cutoff frequency of the resonance region 3100, a second cutoff frequency of the attenuation region 3300 matches (e.g., is equal to or less than) the cutoff frequency of the resonance region 3100, and the first cutoff frequency is equal to or approximately the second cutoff frequency.
It should be noted that the cut-off frequency of the attenuation region is matched with (e.g., equal to or less than) the cut-off frequency of the resonance region, so that the sound wave entering the attenuation region is in an attenuation mode (evanescent mode), that is, the wave number (wave number) in the attenuation region only contains an imaginary part, so that the sound wave is exponentially attenuated. To more clearly illustrate the benefits of embodiments of the present invention, referring to FIG. 9, two exemplary second Type (Type II) sonic dispersion curves 600 are shown. The horizontal axis of the dispersion curve coordinate system represents the wave number, the vertical axis represents the frequency, the origin of the coordinate system represents the wave number as 0, the left side of the origin represents that the wave number only contains an imaginary part, and the right side of the origin represents that the wave number only contains a real part. As shown in fig. 9, a first dispersion curve 601 represents a dispersion relation (dispersion relation) of a resonance region, and an intersection of the first dispersion curve 601 and a vertical axis represents a first cut-off frequency 602 of the resonance region; a second dispersion curve 603 represents the dispersion relation of the attenuation region, the intersection of the second dispersion curve 603 and the vertical axis represents a second cut-off frequency 604 of the attenuation region, and the second cut-off frequency 604 is smaller than the first cut-off frequency 602. Referring again to FIG. 9, for the parallel resonant frequency f p The wave number of the first dispersion curve 601 only includes a real part, and the wave number of the second dispersion curve 603 only includes an imaginary part, so that the sound wave is in an attenuation mode after propagating from the resonance region to the attenuation region, and the sound wave is in an attenuation modeThe wave decays exponentially, and in particular, the expression for the displacement of the acoustic wave includes exp (-jkx), where the wavenumber k contains only imaginary parts. It should be noted that the first Type (Type I) sound wave dispersion curve also has similar dispersion characteristics.
Fig. 10 shows two parallel impedance curves, wherein the abscissa represents frequency and the ordinate represents relative parallel impedance values representing the ratio of the absolute parallel impedance value to a specific parallel impedance value, e.g. 300 ohms for an absolute parallel impedance value and 500 ohms for a specific parallel impedance value, 0.6 (300/500) for a relative parallel impedance value. Referring to fig. 10, a first parallel impedance curve 701 represents a relative parallel impedance curve of a bulk acoustic wave resonator device that does not include a passive structure, and a second parallel impedance curve 703 represents a relative parallel impedance curve of a bulk acoustic wave resonator device that does include a passive structure. As shown in fig. 10, for the parallel resonance frequency f p The corresponding value on the second parallel impedance curve 703 is greater than the corresponding value on the first parallel impedance curve 701. It should be noted that the passive structure can attenuate the laterally propagated sound waves generated in the resonance region, suppress the parasitic edge modes, and increase the Z-dimension p And corresponding Q values. Furthermore, the passive structures are not electrically connected to the electrode layers, so that the passive structure pairs Kt 2 The influence of (c) is small.
In this embodiment, the bulk acoustic wave resonator 3000 further includes: a cavity 3014, the first electrode layer 3004 being located in the cavity 3014, one end of the first electrode extension layer 3005 being located in the cavity 3014, and the first passive structure 3012 being located in the cavity 3014. In another embodiment, a lower electrode layer (e.g., the first electrode layer 3004) may be located over a cavity, covering the cavity; and the passive structure corresponding to the lower electrode layer is positioned outside the cavity.
Fig. 4 is a schematic structural diagram of a section B of a bulk acoustic wave resonator 3000 according to an embodiment of the present invention.
As shown in fig. 4, the bulk acoustic wave resonator device 3000 includes: the piezoelectric layer 3001, the piezoelectric layer 3001 comprising the first side 3002 and the second side 3003; the first electrode layer 3004 is located on the first side 3002 and contacts the piezoelectric layer 3001, the first electrode layer 3004 further includes a fifth edge and a sixth edge opposite to the fifth edge in the horizontal direction, the fifth edge is in a down slope shape, and the sixth edge is in a down slope shape; the second electrode layer 3006 is located on the second side 3003 and contacts the piezoelectric layer 3001, the second electrode layer 3006 further includes a seventh edge and an eighth edge opposite to the seventh edge in the horizontal direction, the seventh edge is in a down slope shape, and the eighth edge is in a down slope shape; in the resonance region 3100, the fifth edge corresponds to the seventh edge in the vertical direction, and the sixth edge corresponds to the eighth edge in the vertical direction; the first passivation layer 3008 on the first side 3002, the first passivation layer 3008 inside the resonance region 3100 covering the first electrode layer 3004, the first passivation layer 3008 outside the resonance region 3100 further covering the piezoelectric layer 3001 outside the fifth edge and the piezoelectric layer 3001 outside the sixth edge; the second passivation layer 3009 on the second side 3003, the second passivation layer 3009 inside the resonant region 3100 covering the second electrode layer 3006, the second passivation layer 3009 outside the resonant region 3100 further covering the piezoelectric layer 3001 outside the seventh edge and the piezoelectric layer 3001 outside the eighth edge; the first overlap layer 3010 is located on the first side 3002 and contacts the first passivation layer 3008, the first overlap layer 3010 includes the first raised portion and the first extended portion, the first raised portion is raised relative to the first extended portion, the first raised portion is located inside the resonance area 3100, and further has an overlapping portion with the first electrode layer 3004 on the fifth edge side and the sixth edge side, the first raised portion and the first electrode layer 3004 are located on both sides of the first passivation layer 3008, the first extended portion is located outside the resonance area 3100, and is also located outside the fifth edge and the sixth edge, and has no overlapping portion with the first electrode layer 3004, and the first extended portion and the piezoelectric layer 3001 are located on both sides of the first passivation layer 3008 in the vertical direction; the second overlap layer 3011 is located on the second side 3003 and contacts the second passivation layer 3009, the second overlap layer 3011 includes the second raised portion and the second extended portion, the second raised portion is raised relative to the second extended portion, the second raised portion is located inside the resonance area 3100, and further has an overlapping portion with the second electrode layer 3006 on the seventh edge side and the eighth edge side, the second raised portion and the second electrode layer 3006 are located on both sides of the second passivation layer 3009, the second extended portion is located outside the resonance area 3100, and is also located outside the seventh edge and the eighth edge, and has no overlapping portion with the second electrode layer 3006, and the second extended portion and the piezoelectric layer 3001 are located on both sides of the second passivation layer 3009 in the vertical direction.
In this embodiment, a region where the first extension portion, the second extension portion, and the piezoelectric layer 3001 overlap is an attenuation region 3400; the third cutoff frequency of the attenuation region 3400 matches (e.g., is equal to or less than) the cutoff frequency of the resonant region 3100.
Fig. 5 is a schematic diagram of a first top-view structure of the bulk acoustic wave resonator 3000 based on the first electrode layer 3004 relative to the cross-section a according to the embodiment of the present invention.
As shown in fig. 5, the bulk acoustic wave resonator device 3000 includes: the first electrode layer 3004 (indicated by a dotted line), the first electrode layer 3004 having a hexagonal shape including the first edge, the second edge, the fifth edge, the sixth edge, the ninth edge, and the tenth edge; the first electrode extension layer 3005 connected to the second edge; the first lap layer 3010 has overlapping portions on a plurality of edge sides of the first electrode layer 3004, is adjacent to the first electrode extension layer 3005, and the first lap layer 3010 includes the first raised portion 3015 and the first extension portion 3016; wherein the first raised part 3015 is located inside an edge of the first electrode layer 3004, and has an overlapping portion with the fifth edge side, the ninth edge side, the first edge side, the sixth edge side, and the tenth edge side; the first extending portion 3016 is located outside the fifth edge, the ninth edge, the first edge, the sixth edge, and the tenth edge, and has no overlapping portion with the first electrode layer 3004.
In this embodiment, the width w of the first butt strap layer 3010 is the same for each edge, accordingly, the width of the first raised portion 3015 is the same for each edge, and the width of the first extending portion 3016 is the same for each edge.
In this embodiment, the first passive structure 3012 includes the first lap layer 3010 adjacent to the first electrode extension layer 3005. In this embodiment, the first passive structure 3012 includes the first raised portion 3015 and has an overlapping portion with the fifth edge side, the ninth edge side, the first edge side, the sixth edge side, and the tenth edge side. In this embodiment, the first passive structure 3012 further includes the first extending portion 3016 located outside the fifth edge, the ninth edge, the first edge, the sixth edge, and the tenth edge and having no overlapping portion with the first electrode layer 3004.
In this embodiment, the width w of each edge of the first passive structure 3012 is the same.
Fig. 6 is a second top view structural diagram of the bulk acoustic wave resonator 3000 according to the embodiment of the present invention, based on the second electrode layer 3006, with respect to the cross section a.
As shown in fig. 6, the bulk acoustic wave resonator device 3000 includes: the second electrode layer 3006 (shown by dotted lines), the second electrode layer 3006 having a hexagonal shape including the third edge, the fourth edge, the seventh edge, the eighth edge, the eleventh edge, and the twelfth edge; the second electrode extension layer 3007 connected to the third edge; the second tab layer 3011 having overlapping portions with a plurality of edge sides of the second electrode layer 3006 and being adjacent to the second electrode extension layer 3007, the second tab layer 3011 including the second raised portion 3017 and the second extension portion 3018; wherein the second raised portion 3017 is located inside an edge of the second electrode layer 3006, and has an overlapping portion with the seventh edge side, the eleventh edge side, the fourth edge side, the eighth edge side, and the twelfth edge side; the second extending portion 3018 is located at the outer side of the seventh edge, the eleventh edge, the fourth edge, the eighth edge, and the twelfth edge, and has no overlapping portion with the second electrode layer 3006.
In this embodiment, the width w of the second butt strap layer 3011 is the same for each edge, accordingly, the width of the second raised portion 3017 is the same for each edge, and the width of the second extending portion 3018 is the same for each edge.
In this embodiment, the second passive structure 3013 includes the second strap layer 3011 adjacent to the second electrode extension layer 3007. In this embodiment, the second passive structure 3013 includes the second raised portion 3017 and has an overlapping portion with the seventh edge side, the eleventh edge side, the fourth edge side, the eighth edge side, and the twelfth edge side. In this embodiment, the second passive structure 3013 further includes a second extending portion 3018 located outside the seventh edge, the eleventh edge, the fourth edge, the eighth edge, and the twelfth edge and having no overlapping portion with the second electrode layer 3006.
In this embodiment, the width w of the second passive structure 3013 is the same for each edge.
In this embodiment, the first passive structure 3012 and the second passive structure 3013 surround the first electrode layer 3004 and the second electrode layer 3006, that is, surround the resonant region 3100.
It should be noted that, in the embodiment of the present invention, the top view of the electrode layer is a hexagon, so the present invention is not limited by the disclosed embodiment, and the top view of the electrode layer may also be other polygons (for example, pentagon, heptagon), ellipse, and the like.
In another embodiment, the bulk acoustic wave resonator includes a plurality of electrode extension layers respectively connected to a plurality of edges of the electrode layer, and the passive structure corresponding to the electrode layer is adjacent to the plurality of electrode extension layers and has a passive overlap with other edges than the plurality of edges, and the passive structure further includes a passive extension portion located outside the other edges.
In another embodiment, a bulk acoustic wave resonating device includes three or more passive structures surrounding a resonating region of the bulk acoustic wave resonating device.
Fig. 11 through 14 show one embodiment of the bulk acoustic wave resonator device of the present invention, but the present invention may be practiced in other ways than those described herein, and thus the present invention is not limited to the embodiments disclosed below. Fig. 11 is a schematic diagram of a first cross-sectional structure of the bulk acoustic wave resonator device and a sound velocity distribution of a corresponding region, fig. 12 is a schematic diagram of a second cross-sectional structure of the bulk acoustic wave resonator device, fig. 13 is a schematic diagram of a first top-view structure of a first electrode layer of the bulk acoustic wave resonator device with respect to the first cross-section, and fig. 14 is a schematic diagram of a second top-view structure of a second electrode layer of the bulk acoustic wave resonator device with respect to the first cross-section.
In this embodiment, the bulk acoustic wave resonator device 3000 is explained in addition to the cross-sectional a structure (fig. 3) of the bulk acoustic wave resonator device in the above-described embodiment, and the difference between this embodiment and the above-described embodiment is that: the bulk acoustic wave resonator device 3000 further includes: a third dielectric portion and a surrounding type groove in the third dielectric portion. The following detailed description will be made in conjunction with the accompanying drawings.
As shown in fig. 11 to 14, the bulk acoustic wave resonator device 3000 further includes: a third dielectric portion (not labeled) on the second side 3003 and contacting the second electrode layer 3006; a surrounding groove 3019 in the third dielectric portion, inside the resonance region 3100, inside the second raised portion, and adjacent to the second raised portion.
In this embodiment, the surrounding type recess 3019 has a polygonal shape. In other embodiments, the circumferential groove may also be circular or oval.
Note that the second passivation layer 3009 includes the third dielectric portion and the second dielectric portion.
In the present embodiment, it is preferred that,by adding the circular groove 3019 inside the resonance region 3100, a first section I formed by the circular groove 3019, and a second section II formed by the first raised portion 3015 and the second raised portion 3017, respectively. By setting the cutoff frequency of the first section region I to be higher than the cutoff frequency of the middle portion (not labeled) of the resonance region 3100 inside the surrounding groove 3019 and setting the cutoff frequency of the second section region II to be lower than the cutoff frequency of the middle portion, a piston mode (piston mode) is formed, see fig. 11, which shows a sound velocity distribution diagram in the piston mode, where the sound velocity is proportional to the cutoff frequency, and the piston mode is excited to suppress the higher-order parasitic mode of the transverse sound wave, as shown in fig. 32, and the series resonance frequency (f) is reduced s ) Near and less than f s Of the portion (c).
To more clearly illustrate the benefits of embodiments of the present invention, referring to FIG. 15, three exemplary second Type (Type II) sonic dispersion curves (Curve 1, curve 2, and Curve 3 in FIG. 15) are shown. The horizontal axis of the dispersion curve coordinate system represents the wave number, the vertical axis represents the frequency, the origin of the coordinate system represents the wave number as 0, the left side of the origin represents that the wave number only contains an imaginary part, and the right side of the origin represents that the wave number only contains a real part. As shown in fig. 15, a first dispersion curve (curve 1 in fig. 15) represents a dispersion relation (dispersion relation) of the middle portion of the resonance region, and an intersection of the first dispersion curve and the vertical axis represents a first cut-off frequency (a in fig. 15) of the resonance region; a second dispersion curve (curve 2 in fig. 15) represents the dispersion relation of the first section I, and the intersection point of the second dispersion curve and the vertical axis represents a second cut-off frequency (b in fig. 15) of the first section I, which is greater than the first cut-off frequency; a third dispersion curve (curve 3 in fig. 15) represents the dispersion relation of the second segment region II, and an intersection of the third dispersion curve and the vertical axis represents a third cut-off frequency (c in fig. 15) of the second segment region II, which is smaller than the first cut-off frequency. Referring again to FIG. 15, for the series resonant frequency (straight line f in FIG. 15) s ) The wavenumber of the first dispersion curve is 0 and is in a resonance mode, and the wavenumber of the second dispersion curve only comprises a real part, so thatThe high-order parasitic mode of the transverse sound wave forms standing wave in the first section area I, the propagation of the sound wave in the resonance area and the second section area II can be transited, and the wave number of the third dispersion curve only comprises an imaginary part, so that the high-order parasitic mode of the transverse sound wave is in an attenuation mode after propagating from the first section area I to the second section area II, specifically, the expression of the displacement of the transverse sound wave comprises exp (-jkx), wherein the wave number k only comprises the imaginary part.
Fig. 32 shows two series admittance curves, where the abscissa represents frequency, the ordinate represents relative series admittance values, and the relative series admittance values represent the ratio of the absolute series admittance value to a specific series admittance value, e.g., 1 siemens for the absolute series admittance value, 2 siemens for the specific series admittance value, and 0.5 (1/2) for the relative series admittance value. Referring to fig. 32, a first series admittance curve (curve 1 in fig. 32) represents a relative series admittance curve of the bulk acoustic wave resonator device excluding the surrounding-type groove 3019 and the passive structure, and a second series admittance curve (curve 2 in fig. 32) represents a relative series admittance curve of the bulk acoustic wave resonator device including the surrounding-type groove 3019 and the passive structure. As shown in fig. 32, for the series resonance frequency f s Near and less than f s The corresponding ripple on the second series admittance curve is smaller than the corresponding ripple on the first series admittance curve. It should be noted that the surrounding-type groove 3019 and the passive structure can form a piston mode in the resonance region 3100, suppress the higher-order parasitic mode of the transverse sound wave, improve the resonator performance, and reduce the series resonance frequency f s Near and less than f s Clutter of the portion (c).
Fig. 16 shows one embodiment of the bulk acoustic wave resonator device of the present invention, but the present invention may be practiced in other ways than those described herein, and thus the present invention is not limited to the embodiments disclosed below. Fig. 16 is a first cross-sectional structural diagram of the bulk acoustic wave resonator device and a sound velocity distribution diagram of a corresponding region.
In this embodiment, the bulk acoustic wave resonator device 3000 is explained in addition to the cross-sectional a structure (fig. 3) of the bulk acoustic wave resonator device in the above-described embodiment, and the difference between this embodiment and the above-described embodiment is that: the bulk acoustic wave resonator device 3000 further includes: a third dielectric portion and a surrounding type groove in the third dielectric portion. The following detailed description will be made in conjunction with the accompanying drawings.
As shown in fig. 16, the bulk acoustic wave resonator device 3000 further includes: a third dielectric portion (not labeled) on the first side 3002 and in contact with the first electrode layer 3004; a surrounding type groove 3019 in the third dielectric portion, inside the resonance region 3100, inside the first raised portion, and adjacent to the first raised portion.
In this embodiment, the surrounding type recess 3019 has a polygonal shape. In other embodiments, the circumferential groove may also be circular or elliptical.
Note that the first passivation layer 3008 includes the third dielectric portion and the first dielectric portion.
In this embodiment, the surrounding groove 3019 is added to the inner side of the resonance region 3100, and a first section I including the surrounding groove 3019 and a second section II including the first raised portion 3015 and the second raised portion 3017 are added. By setting the cutoff frequency of the first section region I to be higher than the cutoff frequency of the middle portion (not labeled) of the resonance region 3100 inside the surrounding groove 3019 and setting the cutoff frequency of the second section region II to be lower than the cutoff frequency of the middle portion, a piston mode (piston mode) is formed, see fig. 16, which shows a sound velocity distribution diagram in the piston mode, where the sound velocity is proportional to the cutoff frequency, and the piston mode is excited to suppress the higher-order parasitic mode of the transverse sound wave, as shown in fig. 32, and the series resonance frequency (f) is reduced s ) Near and less than f s Clutter of the portion (c).
Fig. 17 and 18 show an embodiment of the bulk acoustic wave resonator device of the present invention, but the present invention can be implemented in other ways than those described herein, and thus the present invention is not limited to the embodiments disclosed below. Wherein, fig. 17 is a schematic diagram of a first cross-sectional structure of the bulk acoustic wave resonator device, and fig. 18 is a schematic diagram of a second cross-sectional structure of the bulk acoustic wave resonator device.
Fig. 17 is a schematic structural diagram of a section a of a bulk acoustic wave resonator 8000 according to an embodiment of the present invention.
As shown in fig. 17, the bulk acoustic wave resonator device 8000 includes: a piezoelectric layer 8001, the piezoelectric layer 8001 including a first side 8002 and a second side 8003 opposite the first side 8002 in a vertical direction; a first electrode layer 8004 on the first side 8002 and contacting the piezoelectric layer 8001, wherein the first electrode layer 8004 includes a first edge and a second edge opposite to the first edge in a horizontal direction, and the first edge is in a downward slope shape; a first electrode extension layer 8005, located on the first side 8002, contacting the piezoelectric layer 8001, connecting to the second edge; a second electrode layer 8006 on the second side 8003, contacting the piezoelectric layer 8001, the second electrode layer 8006 including a third edge and a fourth edge opposite to the third edge in a horizontal direction, the fourth edge having a downhill shape; a second electrode extension layer 8007 located at the second side 8003, contacting the piezoelectric layer 8001, and connected to the third edge; an overlapping region of the first electrode layer 8004, the second electrode layer 8006 and the piezoelectric layer 8001 is a resonance region 8100, wherein the first edge vertically corresponds to the third edge, and the second edge vertically corresponds to the fourth edge; the first electrode extension layer 8005 and the second electrode extension layer 8007 are located outside the resonance region 8100 without an overlapping portion; a first passivation layer 8008 on the first side 8002, the first passivation layer 8008 on the inner side of the resonance region 8100 covering the first electrode layer 8004, the first passivation layer 8008 on the outer side of the resonance region 8100 covering the first electrode extension layer 8005 on the outer side of the second edge; a second passivation layer 8009 at the second side 8003, the second passivation layer 8009 located inside the resonance region 8100 covers the second electrode layer 8006, and the second passivation layer 8009 located outside the resonance region 8100 covers the second electrode extension layer 8007 outside the third edge; a first strap layer 8010 on the first side 8002, contacting the first passivation layer 8008, the first strap layer 8010 comprising a first raised portion (not labeled) and a first extended portion (not labeled), the first raised portion being convex with respect to the first extended portion, the first raised portion being located inside the resonance region 8100, and having an overlap with the first electrode layer 8004 on the first edge side, the first raised portion and the first electrode layer 8004 being located on both sides of the first passivation layer 8008, the first extended portion being located outside the resonance region 8100, being located outside the first edge, and having no overlap with the first electrode layer 8004, the first extended portion and the piezoelectric layer 8001 comprising a first empty groove 8015 therebetween; a second overlap layer 8011 on the second side 8003, contacting the second passivation layer 8009, wherein the second overlap layer 8011 includes a second raised portion (not labeled) and a second extended portion (not labeled), the second raised portion is raised with respect to the second extended portion, the second raised portion is located inside the resonance area 8100, and has an overlapping portion with the second electrode layer 8006 on the fourth edge side, the second raised portion and the second electrode layer 8006 are located on both sides of the second passivation layer 8009, the second extended portion is located outside the resonance area 8100, is located outside the fourth edge, and has no overlapping portion with the second electrode layer 8006, and a second empty groove 8016 is included between the second extended portion and the piezoelectric layer 8001.
In this embodiment, the material of the piezoelectric layer 8001 includes but is not limited to 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 8001 is a flat layer, and the piezoelectric layer 8001 includes a plurality of crystal grains, where the plurality of crystal grains includes a first crystal grain and a second crystal grain, where 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 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 includes at least a first coordinate axis along a first direction and a third coordinate axis along a third direction, and the second stereo coordinate system includes at least 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 8001 includes a plurality of grains, and a rocking curve half-width of a crystal formed by the plurality of grains is lower than 2.5 degrees.
In this embodiment, the material of the first electrode layer 8004 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium, and the material of the first electrode extension layer 8005 includes but is not limited to at least one of: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium, copper and gold. In this embodiment, the material of the first electrode layer 8004 is the same as that of the first electrode extension layer 8005.
In this embodiment, the material of the second electrode layer 8006 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium, and the material of the second electrode extension layer 8007 includes, but is not limited to, at least one of: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium, copper and gold. In this embodiment, the material of the second electrode layer 8006 is the same as that of the second electrode extension layer 8007.
In another embodiment, the material of the electrode layer and the material of the electrode extension layer may be different.
In this embodiment, the material of the first passivation layer 8008 includes, but is not limited to, one of the following: silicon dioxide, silicon oxynitride, silicon oxycarbide, silicon nitride, titanium oxide, aluminum oxide, hafnium silicate, zirconium silicate, hafnium dioxide, zirconium dioxide. In this embodiment, the material of the second passivation layer 8009 includes, but is not limited to, one of the following: silicon dioxide, silicon oxynitride, silicon oxycarbide, silicon nitride, titanium oxide, aluminum oxide, hafnium silicate, zirconium silicate, hafnium dioxide, zirconium dioxide. In this embodiment, the first passivation layer 8008 is made of the same material as the second passivation layer 8009. In another embodiment, the material of the first passivation layer (e.g., the first passivation layer 8008) and the material of the second passivation layer (e.g., the second passivation layer 8009) may be different.
In this embodiment, the material of the first strap layer 8010 includes, but is not limited to, at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, aluminum, beryllium. In this embodiment, the first tap layer 8010 is made of the same material as the electrode 8004.
In this embodiment, the material of the second strap layer 8011 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 second tap layer 8011 is the same as that of the electrode 8006.
In another embodiment, the material of the overlap layer and the electrode layer may be different, for example, the material of the overlap layer is tungsten or platinum, and the material of the electrode layer is molybdenum.
In another embodiment, the bead layer includes a first bead layer and a second bead layer, the first bead layer contacts the passivation layer, the second bead layer contacts the first bead layer, the second bead layer and the passivation layer are located on two sides of the first bead layer, the first bead layer is made of a material different from that of the second bead layer, for example, the first bead layer is made of molybdenum, and the second bead layer is made of platinum or tungsten.
In this embodiment, the bulk acoustic wave resonator device 8000 further includes: a first passive structure 8012 on the first side 8002, contacting a first edge of the first electrode layer 8004, the first passive structure 8012 comprising the first ledge layer 8010, a first dielectric portion (not labeled) on the first passivation layer 8008, which overlaps with the first ledge layer 8010, and the first empty groove 8015; and a second passive structure 8013 on the second side 8003 contacting a fourth edge of the second electrode layer 8006, the second passive structure 8013 comprising the second ledge layer 8011, a second dielectric portion (not labeled) on the second passivation layer 8009 coincident with the second ledge layer 8011, and the second empty groove 8016. The dielectric portion may electrically isolate the electrode layer and the overlap layer from each other, and the overlap layer is passive, and a combined structure of the dielectric portion and the overlap layer is also passive.
In this embodiment, the first thickness of the first passive structure 8012 is smaller than the thickness of the first electrode layer 8004, the second thickness of the second passive structure 8013 is smaller than the thickness of the second electrode layer 8006, and the first thickness is equal to or approximately equal to the second thickness.
In this embodiment, a first width of the first raised portion matches an acoustic wavelength of a fundamental mode of transverse acoustic waves generated by the resonating region 8100 (e.g., the first width is equal to an integer multiple of one-half wavelength), a second width of the second raised portion matches an acoustic wavelength of a fundamental mode of transverse acoustic waves generated by the resonating region 8100 (e.g., the second width is equal to an integer multiple of one-half wavelength), and the first width is equal to or approximately equal to the second width. The first raised portion and the second raised portion are used to match acoustic impedances of the resonance region and the attenuation region, so that more of the sound waves generated by the resonance region propagate into the attenuation region.
In this embodiment, a third thickness of the first extending portion is smaller than a thickness of the first electrode layer 8004, a fourth thickness of the second extending portion is smaller than a thickness of the second electrode layer 8006, and the third thickness is equal to or approximately equal to the fourth thickness.
In this embodiment, an overlapping region of the first extending portion, the second electrode extending layer 8007 and the piezoelectric layer 8001 is an attenuation region 8200; the area where the second extending portion, the first electrode extending layer 8005 and the piezoelectric layer 8001 overlap is an attenuation region 8300; a first cutoff frequency of the attenuation region 8200 matches (e.g., is equal to or less than) a cutoff frequency of the resonance region 8100, a second cutoff frequency of the attenuation region 8300 matches (e.g., is equal to or less than) the cutoff frequency of the resonance region 8100, and the first cutoff frequency is equal to or approximately the second cutoff frequency.
It should be noted that, the cut-off frequency of the attenuation region matching the cut-off frequency of the resonance region may make the sound wave entering the attenuation region in an attenuation mode, that is, the wave number in the attenuation region only includes an imaginary part, so that the sound wave is exponentially attenuated. Therefore, the passive structure can attenuate the transversely-propagated sound waves generated in the resonance region, inhibit parasitic edge modes and improve Z p And corresponding Q values. Furthermore, the passive structures are not electrically connected to the electrode layers, so that the passive structures are paired with Kt 2 The influence of (c) is small.
In this embodiment, the bulk acoustic wave resonator 8000 further includes: a cavity 8014, the first electrode layer 8004 is located in the cavity 8014, an end of the first electrode extension layer 8005 is located in the cavity 8014, and the first passive structure 8012 is located in the cavity 8014. In another embodiment, a lower electrode layer (e.g., the first electrode layer 8004) may be located over the cavity, covering the cavity; and the passive structure corresponding to the lower electrode is positioned outside the cavity.
Fig. 18 is a schematic structural diagram of a bulk acoustic wave resonator 8000 according to an embodiment of the present invention in a cross-section B.
As shown in fig. 18, the bulk acoustic wave resonator device 8000 includes: the piezoelectric layer 8001, the piezoelectric layer 8001 including the first side 8002 and the second side 8003; the first electrode layer 8004 is located on the first side 8002 and contacts the piezoelectric layer 8001, the first electrode layer 8004 further includes a fifth edge and a sixth edge opposite to the fifth edge in a horizontal direction, the fifth edge is in a downward slope shape, and the sixth edge is in a downward slope shape; the second electrode layer 8006 is located on the second side 8003 and contacts the piezoelectric layer 8001, the second electrode layer 8006 further includes a seventh edge and an eighth edge opposite to the seventh edge in a horizontal direction, the seventh edge is in a downward slope shape, and the eighth edge is in a downward slope shape; in the resonance area 8100, the fifth edge vertically corresponds to the seventh edge, and the sixth edge vertically corresponds to the eighth edge; the first passivation layer 8008 is positioned at the first side 8002, the first passivation layer 8008 positioned inside the resonance region 8100 covers the first electrode layer 8004; the second passivation layer 8009 on the second side 8003, the second passivation layer 8009 inside the resonance region 8100 covers the second electrode layer 8006; the first ledge layer 8010, located at the first side 8002, contacting the first passivation layer 8008, the first ledge layer 8010 comprising the first raised portion (not labeled) and the first extended portion (not labeled), the first raised portion being raised with respect to the first extended portion, the first raised portion being located inside the resonance region 8100, further having an overlap with the first electrode layer 8004 at the fifth edge side and the sixth edge side, the first raised portion being located with the first electrode layer 8004 on both sides of the first passivation layer 8008, the first extended portion being located outside the resonance region 8100, further being located outside the fifth edge and the sixth edge, having no overlap with the first electrode layer 8004, the first extended portion comprising the first empty groove 8015 between the first extended portion and the piezoelectric layer 8001; the second overlap layer 8011 is located on the second side 8003, and contacts the second passivation layer 8009, the second overlap layer 8011 includes the second raised portion (not labeled) and the second extending portion (not labeled), the second raised portion is raised with respect to the second extending portion, the second raised portion is located inside the resonance region 8100, and further has an overlapping portion with the second electrode layer 8006 on the seventh edge side and the eighth edge side, the second raised portion and the second electrode layer 8006 are located on both sides of the second passivation layer 8009, the second extending portion is located outside the resonance region 8100, and is located outside the seventh edge and the eighth edge, and has no overlapping portion with the second electrode layer 8006, and the second extending portion and the piezoelectric layer 8001 include the second empty groove 8016 therebetween.
In this embodiment, a region where the first extending portion, the second extending portion and the piezoelectric layer 8001 coincide is an attenuation region 8400; a third cutoff frequency of the attenuation region 8400 matches (e.g., is equal to or less than) the cutoff frequency of the resonance region 8100.
In another embodiment, a bulk acoustic wave resonator device includes: a piezoelectric layer including a first side and a second side opposite the first side in a vertical direction; the first electrode layer is positioned on the first side and contacts the piezoelectric layer, the first electrode layer comprises a first edge and a second edge opposite to the first edge in the horizontal direction, and the first edge is in a downhill shape; a first electrode extension layer on the first side, contacting the piezoelectric layer, and connected to the second edge; the second electrode layer is positioned on the second side and contacts the piezoelectric layer, the second electrode layer comprises a third edge and a fourth edge opposite to the third edge in the horizontal direction, and the fourth edge is in a downhill shape; a second electrode extension layer on the second side, contacting the piezoelectric layer, and connected to the third edge; the overlapped area of the first electrode layer, the second electrode layer and the piezoelectric layer is a resonance area, wherein the first edge corresponds to the third edge in the vertical direction, and the second edge corresponds to the fourth edge in the vertical direction; the first electrode extension layer and the second electrode extension layer are positioned outside the resonance area and have no overlapped part; a first overlap layer located on the first side and contacting the piezoelectric layer, the first overlap layer including a first raised portion and a first extended portion, the first raised portion being raised with respect to the first extended portion, the first raised portion being located inside the resonance region, the first raised portion having an overlap with the first electrode layer on the first edge side, a first dielectric portion (e.g., vacuum, air, helium gas) being included between the first raised portion and the first electrode layer, the first extended portion being located outside the resonance region, located outside the first edge, having no overlap with the first electrode layer, the first extended portion contacting the piezoelectric layer; the second overlap layer is located on the second side and contacts the piezoelectric layer, the second overlap layer comprises a second raised portion and a second extending portion, the second raised portion is raised relative to the second extending portion, the second raised portion is located on the inner side of the resonance area, an overlapping portion is formed on the fourth edge side of the second overlap layer and the second electrode layer, a second dielectric portion (for example, vacuum, air or helium) is arranged between the second raised portion and the second electrode layer, the second extending portion is located on the outer side of the resonance area, located on the outer side of the fourth edge and free of overlapping portion with the second electrode layer, and the second extending portion contacts the piezoelectric layer.
In the above another embodiment, the bulk acoustic wave resonator further includes: a first passive structure on the first side contacting the piezoelectric layer, the first passive structure including the first border layer and a first dielectric portion; and a second passive structure on the second side contacting the piezoelectric layer, the second passive structure including the second overlap layer and the second dielectric portion. The dielectric portion may electrically isolate the electrode layer and the overlap layer from each other, so that the overlap layer is passive.
In another embodiment of the foregoing, a region where the first extending portion, the second electrode extending layer and the piezoelectric layer overlap is a first attenuation region; the overlapped area of the second extension part, the first electrode extension layer and the piezoelectric layer is a second attenuation area; a first cutoff frequency of the first attenuation region matches (e.g., is equal to or less than) a cutoff frequency of the resonance region, a second cutoff frequency of the second attenuation region matches (e.g., is equal to or less than) the cutoff frequency of the resonance region, and the first cutoff frequency is equal to or approximately equal to the second cutoff frequency.
It should be noted that, the cut-off frequency of the attenuation region matching the cut-off frequency of the resonance region may make the sound wave entering the attenuation region in an attenuation mode, that is, the wave number in the attenuation region only includes an imaginary part, so that the sound wave is exponentially attenuated. Therefore, the passive structure can attenuate the transversely-propagated sound waves generated in the resonance region, inhibit the parasitic edge mode and improve the Z p And the corresponding Q value. Furthermore, the passive structures are not electrically connected to the electrode layers, so that the passive structures are paired with Kt 2 Has a smaller influence.
Fig. 19 is a schematic structural diagram of a wireless communication apparatus 900. As shown in fig. 19, the wireless communication apparatus 900 includes: the apparatus comprises an rf front-end device 910, a baseband processing device 930, and an antenna 950, wherein a first end of the rf front-end device 910 is connected to the baseband processing device 930, and a second end of the rf front-end device 910 is connected to the antenna 950. Wherein the rf front-end apparatus 910 includes: a first filtering device 911, a second filtering device 913, a multiplexing device 915, a power amplifying device 917 and a low noise amplifying device 919; wherein, the first filtering device 911 is connected to the power amplifying device 917; wherein, the second filtering device 913 is electrically connected to the low noise amplifying device 919; the multiplexing device 915 includes at least one transmitting filter device (not shown) and at least one receiving filter device (not shown). Wherein the first filtering device 911 comprises at least one bulk acoustic wave resonator device provided in one of the above embodiments, and the second filtering device 913 comprises at least one bulk acoustic wave resonator device provided in one of the above embodiments. Wherein the at least one transmitting filter device comprises at least one bulk acoustic wave resonator device as provided in one of the above embodiments, or the at least one receiving filter device comprises at least one bulk acoustic wave resonator device as provided in one of the above embodiments.
Fig. 20 shows one embodiment of a method of forming the bulk acoustic wave resonator device of the present invention, but the present invention can be implemented in other ways than those described herein, and thus the present invention is not limited to the embodiments disclosed below.
Fig. 20 is a flow chart illustrating a method 1000 for forming a bulk acoustic wave resonator device according to an embodiment of the present invention.
An embodiment of the present invention further provides a method 1000 for forming a bulk acoustic wave resonator, including:
s1001, forming a piezoelectric layer, wherein the piezoelectric layer comprises a first side and a second side opposite to the first side in the vertical direction; forming a first electrode layer on the first side contacting the piezoelectric layer; forming a second electrode layer on the second side contacting the piezoelectric layer; the overlapped area of the first electrode layer, the second electrode layer and the piezoelectric layer is a resonance area;
s1003, forming a first passive structure located on the first side and having a first overlapping portion with at least one edge of the first electrode layer, where the first passive structure includes: the first lifting part is raised relative to the first extending part; the first lifting part is positioned on the inner side of the resonance region, the first lifting part and at least one edge of the first electrode layer are provided with the first superposition part, and the first lifting part is used for matching acoustic impedances of the resonance region and at least one attenuation region on the outer side of the resonance region so that more sound waves generated in the resonance region enter the at least one attenuation region; the first dielectric portion is located between the first raised portion and the first electrode layer for electrically isolating the first electrode layer from the first passive structure; the first extension part is positioned outside the resonance region and inside the at least one attenuation region and is used for attenuating the sound waves entering the at least one attenuation region;
s1005, forming a second passive structure on the second side, where the second passive structure has a second overlapping portion with at least one edge of the second electrode layer, and the second passive structure includes: the second lifting part is raised relative to the second extending part; the second lifting part is positioned inside the resonance region, and has a second overlapping part with at least one edge of the second electrode layer, and the second lifting part is used for matching acoustic impedances of the resonance region and the at least one attenuation region so that more sound waves generated in the resonance region enter the at least one attenuation region; the second dielectric portion is located between the second raised portion and the second electrode layer for electrically isolating the second electrode layer from the second passive structure; the second extension is located outside the resonance region, within the at least one attenuation region, and is configured to attenuate sound waves entering the at least one attenuation region.
In some embodiments, the first passive structure and the second passive structure surround the resonance region.
In some embodiments, the first passive structure has a thickness equal to or less than a thickness of the first electrode layer, and the second passive structure has a thickness equal to or less than a thickness of the second electrode layer.
In some embodiments, forming the first electrode layer includes forming at least one tapered edge corresponding to the first passive structure, and forming the second electrode layer includes forming at least one tapered edge corresponding to the second passive structure.
In some embodiments, forming the first passive structure comprises: forming a first passivation layer on the first side to cover the first electrode layer; forming a first lapping layer which contacts the first passivation layer, wherein at least one edge of the first lapping layer and at least one edge of the first electrode layer are provided with the first superposition part; wherein the first passivation layer includes the first dielectric portion; wherein the first lap layer comprises the first raised part and the first extending part.
In some embodiments, forming the second passive structure comprises: forming a second passivation layer on the second side and covering the second electrode layer; forming a second overlap layer contacting the second passivation layer, wherein at least one edge of the second overlap layer and the second electrode layer has the second overlapping portion; wherein the second passivation layer comprises the second dielectric portion; wherein the second lap layer includes the second raised portion and the second extending portion.
In some embodiments, the first extension portion has a thickness less than a thickness of the first electrode layer, and the second extension portion has a thickness less than a thickness of the second electrode layer.
In some embodiments, the at least one attenuation region includes a first attenuation region having a first cutoff frequency equal to or less than a cutoff frequency of the resonance region, the first attenuation region corresponding to a region where the first extension, the piezoelectric layer, and the second extension coincide.
In some embodiments, the method of forming the bulk acoustic wave resonator device further comprises: forming a first electrode extension layer positioned on the first side and connected with the first electrode layer; and forming a second electrode extension layer which is positioned on the second side and is connected with the second electrode layer.
In some embodiments, the at least one attenuation region includes a second attenuation region having a second cutoff frequency equal to or less than a cutoff frequency of the resonance region, the second attenuation region corresponding to a region where the second electrode extension layer, the piezoelectric layer, and the first extension portion coincide.
In some embodiments, the at least one attenuation region includes a third attenuation region having a third cutoff frequency equal to or less than the cutoff frequency of the resonance region, the third attenuation region corresponding to a region where the second extension portion, the piezoelectric layer, and the first electrode extension layer coincide.
In some embodiments, the width of the first raised portion is an integer multiple of one-half wavelength of the acoustic wave generated within the resonance region, and the width of the second raised portion is an integer multiple of one-half wavelength of the acoustic wave generated within the resonance region.
In some embodiments, forming the first bead layer comprises; and forming a first overlap sub-layer and a second overlap sub-layer, wherein the second overlap sub-layer and the piezoelectric layer are positioned at two sides of the first overlap sub-layer, and the material of the first overlap sub-layer is different from that of the second overlap sub-layer.
In some embodiments, forming the second bead layer comprises; and forming a third overlap sub-layer and a fourth overlap sub-layer, wherein the fourth overlap sub-layer and the piezoelectric layer are positioned at two sides of the third overlap sub-layer, and the material of the third overlap sub-layer is different from that of the fourth overlap sub-layer.
In some embodiments, the method of forming the bulk acoustic wave resonator device further comprises: forming a first sacrificial layer between the first extension and the piezoelectric layer; forming a second sacrificial layer between the second extension and the piezoelectric layer.
In some embodiments, the method of forming a bulk acoustic wave resonator device further comprises: removing the first sacrificial layer to form a first empty groove which is positioned between the first extension part and the piezoelectric layer; and removing the second sacrificial layer to form a second empty groove which is positioned between the second extending part and the piezoelectric layer.
In some embodiments, the first dielectric portion is also located between the piezoelectric layer and the first extension, and the second dielectric portion is also located between the piezoelectric layer and the second extension.
In some embodiments, further comprising: forming a third dielectric portion on the second side and in contact with the second electrode layer; forming a surrounding type groove in the third dielectric portion, inside the resonance region, inside the second raised portion, and adjacent to the second raised portion.
In some embodiments, the shape of the encircling groove comprises: circular, elliptical, or polygonal.
In some embodiments, further comprising: forming a third dielectric portion on the first side and in contact with the first electrode layer; forming a surrounding type groove in the third dielectric portion, inside the resonance region, inside the first raised portion, and adjacent to the first raised portion.
In some embodiments, the shape of the circumferential groove comprises: circular, elliptical, or polygonal.
It should be noted that the raised portion of the passive structure is located inside the resonance region, and has a superposition portion with the electrode layer, so that acoustic impedances of the resonance region and the attenuation region outside the resonance region can be matched, and thus more acoustic waves generated by the resonance region propagate into the attenuation region. In addition, the cut-off frequency of the attenuation region is matched with (e.g., equal to or less than) the cut-off frequency of the resonance region, so that the sound wave entering the attenuation region can be attenuated, parasitic edge modes can be suppressed, and the Z can be increased p And corresponding Q values. Wherein, the cut-off frequency is the frequency corresponding to the wave number of 0 on the dispersion curve. Furthermore, the passive structure is not electrically connected to the electrode layers, so that the passive structure pair Kt 2 The influence of (c) is small.
Fig. 21 to 24 show one specific embodiment of the method of forming the bulk acoustic wave resonator device of the present invention, but the present invention may be implemented in other ways than described herein, and thus the present invention is not limited to the specific embodiments disclosed below.
Fig. 21 to 24 are schematic structural diagrams of a cross section a of a method for forming a bulk acoustic wave resonator device 1100 according to an embodiment of the present invention.
As shown in fig. 21, the method of forming the bulk acoustic wave resonator device 1100 includes: forming a piezoelectric layer 1101, the piezoelectric layer 1101 including a first side 1102 and a second side 1103 opposite to the first side 1102 in a vertical direction; forming a first electrode layer 1104 on the first side 1102 and contacting the piezoelectric layer 1101, the first electrode layer 1104 including a first edge and a second edge opposite the first edge in a horizontal direction; a first electrode extension 1105 is formed on said first side 1102 contacting said piezoelectric layer 1101, said first electrode extension 1105 being connected to said second edge.
In this embodiment, the method for forming the bulk acoustic wave resonator device 1100 further includes: prior to forming the piezoelectric layer 1101, a first substrate (not shown) is provided. In this embodiment, the piezoelectric layer 1101 is formed on one side of the first substrate, and the first substrate is located on the second side 1103.
In this embodiment, forming the first electrode layer 1104 includes: forming a first, downwardly sloping edge at said first edge.
As shown in fig. 22, the method of forming the bulk acoustic wave resonator device 1100 further includes: forming a first passivation layer 1106 on the first side 1102, the first passivation layer 1106 covering the first electrode layer 1104, the first passivation layer 1106 further covering the piezoelectric layer 1101 outside the first edge, the first passivation layer 1106 further covering the first electrode extension layer 1105 outside the second edge; forming a first overlap layer 1107 on the first side 1102 to contact the first passivation layer 1106, wherein the first overlap layer 1107 includes a first raised portion (not labeled) and a first extending portion (not labeled), the first raised portion is raised relative to the first extending portion, the first raised portion is located inside the first edge and has an overlapping portion with the first electrode layer 1104 on the first edge side, the first raised portion and the first electrode layer 1104 are located on two sides of the first passivation layer 1106, the first extending portion is located outside the first edge and has no overlapping portion with the first electrode layer 1104, and the first extending portion and the piezoelectric layer 1101 are located on two sides of the first passivation layer 1106 in a vertical direction.
In this embodiment, the method for forming the bulk acoustic wave resonator device 1100 further includes: forming a sacrificial layer 1108 on the first side 1102 covering the first electrode layer 1104, the end of the first electrode extension layer 1105 connected to the second edge, and the first edge layer 1107, wherein the first passivation layer 1106 is included between the sacrificial layer 1108 and the first electrode layer 1104 and the first electrode extension layer 1105.
In this embodiment, the method for forming the bulk acoustic wave resonator device 1100 further includes: a first connection layer (not shown) is formed on the first side 1102, covering the sacrificial layer 1108 and the first passivation layer 1106.
In another embodiment, the method of forming a bulk acoustic wave resonator device further includes: forming a sacrificial layer, wherein the sacrificial layer and a first electrode layer have a superposition part, a first passivation layer is arranged between the sacrificial layer and the first electrode layer, a first lapping layer corresponding to the first electrode layer is positioned on a first side of the sacrificial layer in the horizontal direction, and a first electrode extension layer is positioned on a second side of the sacrificial layer in the horizontal direction; and forming a connecting layer to cover the sacrificial layer and the first passivation layer.
In this embodiment, the method for forming the bulk acoustic wave resonator device 1100 further includes: providing a second substrate (not shown); forming a second connection layer (not shown) on one side of the second substrate to cover the second substrate; bonding the first and second tie layers to form an intermediate layer (not shown), the second substrate and the intermediate layer being on the first side 1102; and removing the first substrate. In this embodiment, bonding the first connection layer and the second connection layer includes: bonding the first and second connection layers or adhering the first and second connection layers.
As shown in fig. 23, the method of forming the bulk acoustic wave resonator device 1100 further includes: forming a second electrode layer 1109 on the second side 1103 and contacting the piezoelectric layer 1101, wherein the second electrode layer 1109 includes a third edge and a fourth edge opposite to the third edge in a horizontal direction; forming a second electrode extension layer 1110 located on the second side 1103 and contacting the piezoelectric layer 1101, wherein the second electrode extension layer 1110 is connected to a third edge of the second electrode layer 1109, the third edge corresponds to the first edge in a vertical direction, and the fourth edge corresponds to the second edge in a vertical direction.
In this embodiment, forming the second electrode layer 1109 includes: forming a second downhill edge, located at said fourth edge.
As shown in fig. 24, the method of forming the bulk acoustic wave resonator device 1100 further includes: forming a second passivation layer 1111 on the second side 1103, the second passivation layer 1111 covering the second electrode layer 1109, the second passivation layer 1111 further covering the piezoelectric layer 1101 outside the fourth edge, the second passivation layer 1111 further covering the second electrode extension layer 1110 outside the third edge; forming a second overlap layer 1112 located at the second side 1103 contacting the second passivation layer 1111, the second overlap layer 1112 including a second raised portion (not labeled) and a second extension portion (not labeled), the second raised portion being raised with respect to the second extension portion, the second raised portion being located at the inner side of the fourth edge, having an overlap with the second electrode layer 1109 at the fourth edge side, the second raised portion and the second electrode layer 1109 being located at both sides of the second passivation layer 1111, the second extension portion being located at the outer side of the fourth edge, having no overlap with the second electrode layer 1109, the second extension portion and the piezoelectric layer 1101 being located at both sides of the second passivation layer 1111 in the vertical direction.
In this embodiment, the method for forming the bulk acoustic wave resonator device 1100 further includes: and removing the sacrificial layer 1108 to form a cavity 1113, wherein the first electrode layer 1104, the end of the first electrode extension layer 1105 connected to the second edge, and the first edge covering layer 1107 are located in the cavity 1113.
In this embodiment, a first passive structure 1114 is formed on the first capping layer 1107 and a first dielectric portion (not labeled) of the first passivation layer 1106 that overlaps with the first capping layer 1107, and is located on the first side 1102 and contacts a first edge of the first electrode layer 1104 and the piezoelectric layer 1101 outside the first edge; second dielectric portions (not labeled) on the second landing leg layer 1112 and the second passivation layer 1111 coincident with the second landing leg layer 1112 form second passive structures 1115 on the second side 1103 contacting the piezoelectric layer 1101 at fourth and outside of the fourth edge of the second electrode layer 1109. The dielectric portion may electrically isolate the electrode layer and the overlap layer from each other, and the overlap layer is passive, and a combined structure of the dielectric portion and the overlap layer is also passive.
In this embodiment, a first thickness of the first passive structure 1114 is smaller than a thickness of the first electrode layer 1104, a second thickness of the second passive structure 1115 is smaller than a thickness of the second electrode layer 1109, and the first thickness is equal to or approximately equal to the second thickness.
In this embodiment, an overlapping region of the first electrode layer 1104, the second electrode layer 1109, and the piezoelectric layer 1101 is a resonance region 1120, and an overlapping region of the first extension portion, the second electrode extension layer 1110, and the piezoelectric layer 1101 is an attenuation region 1130; the overlapped area of the second extension portion, the first electrode extension layer 1105 and the piezoelectric layer 1101 is an attenuation region 1140; a first cutoff frequency of the attenuation region 1130 matches (e.g., is equal to or less than) a cutoff frequency of the resonance region 1120, a second cutoff frequency of the attenuation region 1140 matches (e.g., is equal to or less than) the cutoff frequency of the resonance region 1120, and the first cutoff frequency is equal to or approximately the second cutoff frequency.
In this embodiment, a first width of the first raised portion matches an acoustic wavelength of a fundamental mode of a transverse acoustic wave generated by the resonance region (e.g., a rayleigh S1 mode, or a TE1 mode) (e.g., the first width is equal to an integer multiple of one-half wavelength), a second width of the second raised portion matches an acoustic wavelength of a fundamental mode of a transverse acoustic wave generated by the resonance region (e.g., the second width is equal to an integer multiple of one-half wavelength), and the first width is equal to or approximately equal to the second width. The first raised portion and the second raised portion are used to match acoustic impedances of the resonance region and the attenuation region, so that more of the sound waves generated by the resonance region propagate into the attenuation region.
In this embodiment, a third thickness of the first extension portion is smaller than a thickness of the first electrode layer 1104, a fourth thickness of the second extension portion is smaller than a thickness of the second electrode layer 1109, and the third thickness is equal to or approximately equal to the fourth thickness.
It should be noted that the cutoff frequency of the attenuation region is matched with the cutoff frequency of the resonance region, so that the sound wave entering the attenuation region is in an attenuation mode, that is, the wave number in the attenuation region only includes an imaginary part, and the sound wave is exponentially attenuated, so that the transversely-propagated sound wave generated in the resonance region can be attenuated, the parasitic edge mode is suppressed, and the Z-dimension is increased p And the corresponding Q value. Furthermore, the passive structures are not electrically connected to the electrode layers, so that the passive structures are paired with Kt 2 Has a smaller influence.
In another embodiment, forming the bead layer includes: forming a first overlap sub-layer contacting the passivation layer; forming a second overlap sub-layer in contact with the first overlap sub-layer, where the passivation layer and the second overlap sub-layer are located on two sides of the first overlap sub-layer, where a material of the first overlap sub-layer is different from a material of the second overlap sub-layer, for example, the first overlap sub-layer is made of molybdenum, and the second overlap sub-layer is made of platinum or tungsten.
Fig. 25 shows one specific embodiment of the method of forming the bulk acoustic wave resonator device of the present invention, but the present invention may be implemented in other ways than those described herein, and thus the present invention is not limited to the specific embodiments disclosed below.
In the present embodiment, the description of the bulk acoustic wave resonator device is continued on the basis of the method for forming the bulk acoustic wave resonator device 1100 in the above-described embodiment, and the difference between the present embodiment and the above-described embodiment is that: the bulk acoustic wave resonator device 1100 also includes a third dielectric portion and a surrounding type recess. The following detailed description will be made in conjunction with the accompanying drawings.
As shown in fig. 25, the method for forming the bulk acoustic wave resonator device 1100 described above further includes, in addition to fig. 24, the following steps in fig. 25: forming a third dielectric portion (not labeled) on the second side 1103 and in contact with the second electrode layer 1109; a wrap-around groove 1116 in the third dielectric portion, inside the resonance region 1120, inside the second raised portion, and adjacent to the second raised portion.
In this embodiment, the circumferential groove 1116 has a polygonal shape. In other embodiments, the circumferential groove may also be circular or elliptical.
Note that the second passivation layer 1111 includes the third dielectric portion and the second dielectric portion.
In this embodiment, the surrounding groove 1116, the first section region I formed by the surrounding groove 1116, and the second section region II formed by the first raised portion and the second raised portion are added inside the resonance region 1120. By setting the cutoff frequency of the first section region I to be higher than the cutoff frequency of the middle portion (not labeled) of the resonance region 1120 inside the surrounding-type groove 1116 and setting the cutoff frequency of the second section region II to be lower than the cutoff frequency of the middle portion, a piston mode (piston mode) is formed, see fig. 25, which shows a sound velocity distribution diagram in the piston mode, where the sound velocity is proportional to the cutoff frequency, and the piston mode is excited to suppress the higher-order parasitic mode of the transverse sound wave, as shown in fig. 32, and the series resonance frequency (f) is reduced s ) Near and less than f s Clutter of the portion (c).
Fig. 26 and 27 show one embodiment of a method of forming the bulk acoustic wave resonator device of the present invention, but the present invention can be implemented in other ways than those described herein, and thus the present invention is not limited to the embodiments disclosed below.
In the present embodiment, the description of the bulk acoustic wave resonator device is continued on the basis of the method for forming the bulk acoustic wave resonator device 1100 in the above-described embodiment, and the difference between the present embodiment and the above-described embodiment is that: the bulk acoustic wave resonator device 1100 further includes a third dielectric portion and a surrounding type groove therein. The following detailed description will be made in conjunction with the accompanying drawings.
As shown in fig. 26, it should be noted that fig. 26 is continued on the basis of fig. 22, and the method for forming the bulk acoustic wave resonator device 1100 further includes: forming a third dielectric portion (not labeled) on the first side 1102 and in contact with the first electrode layer 1104; a wrap-around groove 1116 in the third dielectric portion, inside the resonance region 1120, inside the first raised portion, and adjacent to the first raised portion.
In this embodiment, the circumferential groove 1116 has a polygonal shape. In other embodiments, the circumferential groove may also be circular or oval.
Note that the first passivation layer 1106 includes the third dielectric portion and the first dielectric portion.
It should be noted that after the surrounding type groove is formed, the subsequent processes are consistent with fig. 23 and fig. 24 and the corresponding description until the bulk acoustic wave resonator device 1100 is formed (as shown in fig. 27).
In this embodiment, the surrounding groove 1116, the first section region I formed by the surrounding groove 1116, and the second section region II formed by the first raised portion and the second raised portion are added inside the resonance region 1120. By setting the cutoff frequency of the first section region I to be higher than the cutoff frequency of the intermediate portion (not labeled) of the resonance region 1120 inside the surrounding-type groove 1116 and setting the cutoff frequency of the second section region II to be lower than the cutoff frequency of the intermediate portion, a piston mode (piston mode) is formed, see fig. 11, which shows a sound velocity distribution diagram in a piston mode where the sound velocity is proportional to the cutoff frequency, and the piston mode is excited to suppress higher-order spurious modes of transverse sound waves, as shown in fig. 32, and the series resonance frequency is reduced(f s ) Near and less than f s Of the portion (c).
Fig. 28 to 31 show one specific embodiment of the method of forming the bulk acoustic wave resonator device of the present invention, but the present invention may be implemented in other ways than those described herein, and thus the present invention is not limited to the specific embodiment disclosed below.
Fig. 28 to 31 are schematic structural diagrams of a cross section a of a method for forming a bulk acoustic wave resonator 1200 according to an embodiment of the present invention.
As shown in fig. 28, the method of forming the bulk acoustic wave resonator device 1200 includes: forming a piezoelectric layer 1201, the piezoelectric layer 1201 including a first side 1202 and a second side 1203 vertically opposing the first side 1202; forming a first electrode layer 1204 on the first side 1202 contacting the piezoelectric layer 1201, the first electrode layer 1204 comprising a first edge and a second edge opposite to the first edge in a horizontal direction; a first electrode extension 1205 is formed on the first side 1202 contacting the piezoelectric layer 1201, the first electrode extension 1205 being connected to the second edge.
In this embodiment, the method for forming the bulk acoustic wave resonator 1200 further includes: before forming the piezoelectric layer 1201, a first substrate (not shown) is provided. In this embodiment, the piezoelectric layer 1201 is formed on one side of the first substrate, and the first substrate is located on the second side 1203.
In this embodiment, forming the first electrode layer 1204 includes: forming a first, downwardly sloping edge at said first edge.
As shown in fig. 29, the method of forming the bulk acoustic wave resonator device 1200 further includes: forming a first passivation layer 1206 on the first side 1202, the first passivation layer 1206 covering the first electrode layer 1204 and also covering the first electrode extension layer 1205 outside the second edge; forming a first sacrificial layer 1207 on the first side 1202, outside the first edge, contacting the piezoelectric layer 1201 and the first passivation layer 1206; forming a first overlap layer 1208 on the first side 1202 to contact the first passivation layer 1206 and the first sacrificial layer 1207, where the first overlap layer 1208 includes a first raised portion (not labeled) and a first extending portion (not labeled), the first raised portion is raised relative to the first extending portion, the first raised portion is located inside the first edge and has an overlap with the first electrode layer 1204 on the first edge side, the first raised portion and the first electrode layer 1204 are located on two sides of the first passivation layer 1206, the first extending portion is located outside the first edge and has no overlap with the first electrode layer 1204, and the first extending portion and the piezoelectric layer 1201 are located on two sides of the first sacrificial layer 1207 in a vertical direction.
In this embodiment, the method for forming the bulk acoustic wave resonator 1200 further includes: forming a second sacrificial layer 1209 on the first side 1202, covering the first electrode layer 1204, an end of the first electrode extension layer 1205 connected to the second edge, the first lap layer 1208, and the first sacrificial layer 1207, wherein the first passivation layer 1206 is included between the second sacrificial layer 1209 and the first electrode layer 1204 and the first electrode extension layer 1205.
In this embodiment, the method for forming the bulk acoustic wave resonator 1200 further includes: a first connection layer (not shown) is formed on the first side 1202 covering the second sacrificial layer 1209 and the piezoelectric layer 1201.
In this embodiment, the method for forming the bulk acoustic wave resonator 1200 further includes: providing a second substrate (not shown); forming a second connection layer (not shown) on one side of the second substrate to cover the second substrate; bonding the first and second tie layers to form an intermediate layer (not shown), the second substrate and the intermediate layer being located on the first side 1202; and removing the first substrate. In this embodiment, bonding the first connection layer and the second connection layer includes: bonding the first and second connection layers or adhering the first and second connection layers.
As shown in fig. 30, the method of forming the bulk acoustic wave resonator device 1200 further includes: forming a second electrode layer 1210 on the second side 1203, contacting the piezoelectric layer 1201, the second electrode layer 1210 including a third edge and a fourth edge opposite to the third edge in a horizontal direction; forming a second electrode extension 1211 located on the second side 1203 and contacting the piezoelectric layer 1201, wherein the second electrode extension 1211 is connected to a third edge of the second electrode layer 1210, wherein the third edge vertically corresponds to the first edge, and the fourth edge vertically corresponds to the second edge.
In this embodiment, forming the second electrode layer 1210 includes: forming a second downhill edge located at said fourth edge.
As shown in fig. 31, the method for forming the bulk acoustic wave resonator device 1200 further includes: forming a second passivation layer 1212 at the second side 1203, wherein the second passivation layer 1212 covers the second electrode layer 1210 and also covers the second electrode extension 1211 outside the third edge; forming a dummy sacrificial layer (not shown), for example, the first sacrificial layer 1207, on the second side 1203, outside the fourth edge, contacting the piezoelectric layer 1201 and the second passivation layer 1212; forming a second overlap layer 1213 on the second side 1203 to contact the second passivation layer 1212 and the empty trench sacrificial layer, where the second overlap layer 1213 includes a second raised portion (not labeled) and a second extending portion (not labeled), the second raised portion is raised relative to the second extending portion, the second raised portion is located inside the fourth edge, the second raised portion and the second electrode layer 1210 have an overlapping portion on the fourth edge side, the second raised portion and the second electrode layer 1210 are located on two sides of the second passivation layer 1212, the second extending portion is located outside the fourth edge, the second extending portion and the piezoelectric layer 1201 are located on two sides of the empty trench sacrificial layer in the vertical direction.
In this embodiment, the method for forming the bulk acoustic wave resonator 1200 further includes: the second sacrificial layer 1209 is removed to form a cavity 1214, and the first electrode layer 1204, the end of the first electrode extension layer 1205 connected to the second edge, and the first bonding edge layer 1208 are located in the cavity 1214.
In this embodiment, the method for forming the bulk acoustic wave resonator 1200 further includes: the first sacrificial layer 1207 and the empty slot sacrificial layer are removed, forming a first empty slot 1215 and a second empty slot 1216, respectively.
In this embodiment, the first ledge layer 1208, a first dielectric portion (not labeled) of the first passivation layer 1206 that coincides with the first ledge layer 1208, and the first empty slot 1215 form a first passive structure 1217 on the first side 1202 contacting a first edge of the first electrode layer 1204; the second ledge layer 1213, a second dielectric portion (not labeled) on the second passivation layer 1212 that coincides with the second ledge layer 1213, and the second empty trench 1216 form a second passive structure 1218 on the second side 1203, contacting a fourth edge of the second electrode layer 1210. The dielectric portion may electrically isolate the electrode layer and the overlap layer from each other to prevent conduction therebetween, so that the overlap layer is passive, and a combined structure of the dielectric portion and the overlap layer is also passive.
In this embodiment, a first thickness of the first passive structure 1217 is smaller than a thickness of the first electrode layer 1204, a second thickness of the second passive structure 1218 is smaller than a thickness of the second electrode layer 1210, and the first thickness is equal to or approximately equal to the second thickness.
In this embodiment, a region where the first electrode layer 1204, the second electrode layer 1210, and the piezoelectric layer 1201 overlap is a resonance region 1220, and a region where the first extension portion, the second electrode extension layer 1211, and the piezoelectric layer 1201 overlap is a first attenuation region 1230; a region where the second extension portion, the first electrode extension layer 1205 and the piezoelectric layer 1201 are overlapped is a second attenuation region 1240; a first cutoff frequency of the first attenuation region 1230 matches (e.g., is equal to or less than) a cutoff frequency of the resonance region 1220, a second cutoff frequency of the second attenuation region 1240 matches (e.g., is equal to or less than) the cutoff frequency of the resonance region 1220, and the first cutoff frequency is equal to or approximately the second cutoff frequency.
In this embodiment, a first width of the first raised portion matches an acoustic wavelength of a fundamental mode of transverse acoustic waves generated by the resonance region 1220 (e.g., the first width is equal to an integer multiple of one-half wavelength), a second width of the second raised portion matches an acoustic wavelength of a fundamental mode of transverse acoustic waves generated by the resonance region 1220 (e.g., the second width is equal to an integer multiple of one-half wavelength), and the first width is equal to or approximately equal to the second width. It should be noted that the first raised portion and the second raised portion are used for matching acoustic impedances of the resonance region and the attenuation region, so that more sound waves generated by the resonance region propagate into the attenuation region.
In this embodiment, a third thickness of the first extension portion is smaller than a thickness of the first electrode layer 1204, a fourth thickness of the second extension portion is smaller than a thickness of the second electrode layer 1210, and the third thickness is equal to or approximately equal to the fourth thickness.
It should be noted that the cutoff frequency of the attenuation region is matched with the cutoff frequency of the resonance region, so that the sound wave entering the attenuation region is in an attenuation mode, that is, the wave number in the attenuation region only includes an imaginary part, and the sound wave is exponentially attenuated, so that the transversely-propagated sound wave generated in the resonance region can be attenuated, the parasitic edge mode is suppressed, and the Z-dimension is increased p And corresponding Q values. Furthermore, the passive structures are not electrically connected to the electrode layers, so that the passive structures are paired with Kt 2 Has a smaller influence.
In another embodiment, forming the bead layer includes: forming a first overlap sub-layer contacting the passivation layer; and forming a second overlap sub-layer to contact the first overlap sub-layer, wherein the passivation layer and the second overlap sub-layer are located on two sides of the first overlap sub-layer, the material of the first overlap sub-layer is different from that of the second overlap sub-layer, for example, the material of the first overlap sub-layer is molybdenum, and the material of the second overlap sub-layer is platinum or tungsten.
In summary, the passive structure includes a raised portion located inside the resonance region and having an overlap with the electrode layer, and the acoustic impedances of the resonance region and the attenuation region can be matched, so that more sound waves generated by the resonance region are propagated into the attenuation region. In addition, of said attenuation zoneThe cutoff frequency matches (e.g., is equal to or less than) the cutoff frequency of the resonance region, thereby attenuating sound waves entering the attenuation region, suppressing parasitic edge modes, and raising Z p And corresponding Q values. Furthermore, the passive structures are not electrically connected to the electrode layers, so that the passive structure pairs Kt 2 The influence of (c) is small.
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 (44)
1. A bulk acoustic wave resonator device, comprising:
a cavity;
a first electrode layer, at least one end of the first electrode layer being located above the cavity or within the cavity;
the piezoelectric layer comprises a first side and a second side opposite to the first side in the vertical direction, the cavity is located on the first side, the first electrode layer is located on the first side, and the first electrode layer is in contact with the piezoelectric layer;
the second electrode layer is positioned on the second side and contacts the piezoelectric layer, and the superposed area of the first electrode layer, the second electrode layer and the piezoelectric layer is a resonance area;
a first passive structure located on the first side and having a first overlap with at least one edge of the first electrode layer;
a second passive structure located on the second side and having a second overlap with at least one edge of the second electrode layer;
wherein the first passive structure comprises:
a first raised portion located inside the resonance region and having the first overlapping portion with at least one edge of the first electrode layer, the first raised portion being configured to match acoustic impedances of the resonance region and at least one attenuation region outside the resonance region, so that more of the sound waves generated in the resonance region enter the at least one attenuation region;
a first dielectric portion between the first raised portion and the first electrode layer for electrically isolating the first electrode layer from the first passive structure;
a first extension portion located outside the resonance region and inside the at least one attenuation region for attenuating the sound waves entering the at least one attenuation region, the first raised portion being raised with respect to the first extension portion;
the second passive structure includes:
a second raised portion located inside the resonance region and having a second overlap portion with at least one edge of the second electrode layer, the second raised portion being configured to match acoustic impedances of the resonance region and the at least one attenuation region, so that more of the sound waves generated in the resonance region enter the at least one attenuation region;
a second dielectric portion between the second raised portion and the second electrode layer for electrically isolating the second electrode layer from the second passive structure;
the second extending portion is located outside the resonance region and inside the at least one attenuation region and used for attenuating the sound waves entering the at least one attenuation region, and the second lifting portion is convex relative to the second extending portion.
2. The bulk acoustic wave resonator device of claim 1, wherein the first passive structure and the second passive structure surround the resonance region.
3. The bulk acoustic wave resonator device according to claim 1, wherein a thickness of the first passive structure is equal to or less than a thickness of the first electrode layer, and a thickness of the second passive structure is equal to or less than a thickness of the second electrode layer.
4. The bulk acoustic wave resonator device according to claim 1, wherein at least one of the attenuation regions comprises a first attenuation region having a first cutoff frequency equal to or lower than a cutoff frequency of the resonance region, the first attenuation region corresponding to a region where the first extension, the piezoelectric layer, and the second extension coincide.
5. The bulk acoustic wave resonator device of claim 1, further comprising: a first electrode extension layer located at the first side and connected with the first electrode layer; a second electrode extension layer on the second side, connected to the second electrode layer.
6. The bulk acoustic wave resonator device according to claim 5, wherein at least one of the attenuation regions includes a second attenuation region having a second cutoff frequency equal to or lower than a cutoff frequency of the resonance region, the second attenuation region corresponding to a region where the second electrode extension layer, the piezoelectric layer, and the first extension portion coincide with each other.
7. The bulk acoustic wave resonator device according to claim 5, wherein at least one of the attenuation regions comprises a third attenuation region having a third cutoff frequency equal to or lower than a cutoff frequency of the resonance region, the third attenuation region corresponding to a region where the second extension portion, the piezoelectric layer, and the first electrode extension layer coincide.
8. The bulk acoustic wave resonator device according to claim 1, wherein at least one edge of the first electrode layer is downsloped corresponding to the first passive structure and at least one edge of the second electrode layer is downsloped corresponding to the second passive structure.
9. The bulk acoustic wave resonator device according to claim 1, wherein the width of the first raised portion is an integral multiple of one-half wavelength of the acoustic wave generated in the resonance region, and the width of the second raised portion is an integral multiple of one-half wavelength of the acoustic wave generated in the resonance region.
10. The bulk acoustic wave resonator device according to claim 1, wherein a thickness of the first extension portion is smaller than a thickness of the first electrode layer, and a thickness of the second extension portion is smaller than a thickness of the second electrode layer.
11. The bulk acoustic wave resonator device according to claim 1, wherein the first extension portion includes a first sub-portion and a second sub-portion, the second sub-portion and the piezoelectric layer are located on both sides of the first sub-portion, and a material of the first sub-portion is different from a material of the second sub-portion.
12. The bulk acoustic wave resonator device according to claim 1, wherein the second extension portion includes a third sub-portion and a fourth sub-portion, the piezoelectric layer and the fourth sub-portion are located on both sides of the third sub-portion, and a material of the third sub-portion is different from a material of the fourth sub-portion.
13. The bulk acoustic wave resonator device of claim 1, wherein the first extension contacts the piezoelectric layer and the second extension contacts the piezoelectric layer.
14. The bulk acoustic wave resonator device of claim 1, wherein the first dielectric portion is further located between the piezoelectric layer and the first extension, and the second dielectric portion is further located between the piezoelectric layer and the second extension.
15. The bulk acoustic wave resonator device of claim 1, wherein a first void is included between the first extension and the piezoelectric layer, and a second void is included between the piezoelectric layer and the second extension.
16. The bulk acoustic wave resonator device of claim 1, further comprising: a third dielectric portion on the second side and in contact with the second electrode layer; a surrounding type groove located in the third dielectric portion, located inside the resonance region, located inside the second raised portion, and adjacent to the second raised portion.
17. The bulk acoustic wave resonator device of claim 16, wherein the shape of the surround-type groove comprises: circular, elliptical, or polygonal.
18. The bulk acoustic wave resonator device of claim 1, further comprising: a third dielectric portion on the first side and in contact with the first electrode layer; a surrounding type groove located in the third dielectric portion, located inside the resonance region, located inside the first raised portion, and adjacent to the first raised portion.
19. The bulk acoustic wave resonator device of claim 18, wherein the shape of the surround-type groove comprises: circular, elliptical, or polygonal.
20. A filtering apparatus, comprising: at least one bulk acoustic wave resonator device as claimed in any one of claims 1 to 19.
21. A radio frequency front end device, comprising: power amplifying means and at least one filtering means according to claim 20; the power amplifying device is connected with the filtering device.
22. A radio frequency front end device, comprising: low noise amplifying means associated with at least one filtering means according to claim 20; the low-noise amplifying device is connected with the filtering device.
23. A radio frequency front end device, comprising: multiplexing device comprising at least one filtering device according to claim 20.
24. A method of forming a bulk acoustic wave resonator device, comprising:
forming a piezoelectric layer including a first side and a second side opposite the first side in a vertical direction;
forming a first electrode layer on the first side contacting the piezoelectric layer;
forming a second electrode layer, which is positioned on the second side and contacts the piezoelectric layer, wherein the overlapped area of the first electrode layer, the second electrode layer and the piezoelectric layer is a resonance area;
forming a first passive structure, located on the first side, having a first overlap with at least one edge of the first electrode layer;
wherein the first passive structure comprises:
the first lifting part is raised relative to the first extending part; the first lifting part is positioned on the inner side of the resonance region, the first lifting part is provided with a first superposition part with at least one edge of the first electrode layer, and the first lifting part is used for matching acoustic impedances of the resonance region and at least one attenuation region on the outer side of the resonance region so that more sound waves generated in the resonance region enter the at least one attenuation region; the first dielectric portion is located between the first raised portion and the first electrode layer for electrically isolating the first electrode layer from the first passive structure; the first extension part is positioned outside the resonance region and in at least one attenuation region and is used for attenuating sound waves entering the at least one attenuation region;
forming a second passive structure on the second side having a second overlap with at least one edge of the second electrode layer,
wherein the second passive structure comprises:
the second lifting part is raised relative to the second extension part; the second lifting part is positioned inside the resonance region, and has a second overlapping part with at least one edge of the second electrode layer, and the second lifting part is used for matching acoustic impedances of the resonance region and at least one attenuation region so that more sound waves generated in the resonance region enter at least one attenuation region; the second dielectric portion is located between the second raised portion and the second electrode layer for electrically isolating the second electrode layer from the second passive structure; the second extension portion is located outside the resonance region and inside the at least one attenuation region, and is used for attenuating the sound wave entering the at least one attenuation region.
25. The method of forming a bulk acoustic wave resonator device of claim 24, wherein the first passive structure and the second passive structure surround the resonance region.
26. The method of forming a bulk acoustic wave resonator device according to claim 24, wherein the first passive structure has a thickness equal to or less than a thickness of the first electrode layer, and the second passive structure has a thickness equal to or less than a thickness of the second electrode layer.
27. The method of forming a bulk acoustic wave resonator device according to claim 24, wherein forming the first electrode layer includes forming at least one tapered edge corresponding to the first passive structure, and forming the second electrode layer includes forming at least one tapered edge corresponding to the second passive structure.
28. The method of forming a bulk acoustic wave resonator device according to claim 24, wherein forming the first passive structure comprises forming a first passivation layer on the first side covering the first electrode layer; forming a first overlap layer in contact with the first passivation layer, wherein at least one edge of the first overlap layer and at least one edge of the first electrode layer have the first overlapping portion; wherein the first passivation layer includes the first dielectric portion; wherein the first lap layer comprises the first raised part and the first extending part.
29. The method of forming a bulk acoustic wave resonator device according to claim 24, wherein forming the second passive structure comprises forming a second passivation layer on the second side overlying the second electrode layer; forming a second overlap layer contacting the second passivation layer, wherein at least one edge of the second overlap layer and the second electrode layer has the second overlapping portion; wherein the second passivation layer comprises the second dielectric portion; wherein the second lap layer includes the second raised portion and the second extending portion.
30. The method of forming a bulk acoustic wave resonator device according to claim 24, wherein a thickness of the first extension portion is smaller than a thickness of the first electrode layer, and a thickness of the second extension portion is smaller than a thickness of the second electrode layer.
31. The method of forming a bulk acoustic wave resonator device according to claim 24, wherein at least one of the attenuation regions includes a first attenuation region having a first cutoff frequency equal to or lower than a cutoff frequency of the resonator region, the first attenuation region corresponding to a region where the first extension portion, the piezoelectric layer, and the second extension portion overlap.
32. The method of forming a bulk acoustic wave resonator device according to claim 24, further comprising: forming a first electrode extension layer positioned on the first side and connected with the first electrode layer; and forming a second electrode extension layer which is positioned on the second side and is connected with the second electrode layer.
33. The method of forming a bulk acoustic wave resonator device according to claim 32, wherein at least one of the attenuation regions includes a second attenuation region having a second cutoff frequency equal to or lower than a cutoff frequency of the resonance region, the second attenuation region corresponding to an overlapping area of the second electrode extension layer, the piezoelectric layer, and the first extension portion.
34. The method of forming a bulk acoustic wave resonator device according to claim 32, wherein at least one of the attenuation regions includes a third attenuation region having a third cutoff frequency equal to or lower than a cutoff frequency of the resonance region, the third attenuation region corresponding to a region where the second extension portion, the piezoelectric layer, and the first electrode extension layer coincide.
35. The method of forming a bulk acoustic wave resonator device according to claim 24, wherein the width of the first raised portion is an integral multiple of one-half wavelength of the acoustic wave generated in the resonance region, and the width of the second raised portion is an integral multiple of one-half wavelength of the acoustic wave generated in the resonance region.
36. The method of forming a bulk acoustic wave resonator device according to claim 28, wherein forming the first overlap layer comprises; forming a first butt-strap sublayer and a second butt-strap sublayer, wherein the second butt-strap sublayer and the piezoelectric layer are positioned on two sides of the first butt-strap sublayer, and the material of the first butt-strap sublayer is different from that of the second butt-strap sublayer.
37. The method of forming a bulk acoustic wave resonator device according to claim 29, wherein forming the second fillet layer comprises; and forming a third overlap sub-layer and a fourth overlap sub-layer, wherein the fourth overlap sub-layer and the piezoelectric layer are positioned at two sides of the third overlap sub-layer, and the material of the third overlap sub-layer is different from that of the fourth overlap sub-layer.
38. The method of forming a bulk acoustic wave resonator device according to claim 24, further comprising: forming a first sacrificial layer between the first extension and the piezoelectric layer; forming a second sacrificial layer between the second extension and the piezoelectric layer.
39. The method of forming a bulk acoustic wave resonator device according to claim 38, further comprising: removing the first sacrificial layer to form a first empty groove located between the first extending portion and the piezoelectric layer; and removing the second sacrificial layer to form a second empty groove which is positioned between the second extending part and the piezoelectric layer.
40. The method of forming a bulk acoustic wave resonator device according to claim 24, wherein the first dielectric portion is further located between the piezoelectric layer and the first extension, and the second dielectric portion is further located between the piezoelectric layer and the second extension.
41. The method of forming a bulk acoustic wave resonator device according to claim 24, further comprising: forming a third dielectric portion on the second side and in contact with the second electrode layer; forming a surrounding type groove in the third dielectric portion, inside the resonance region, inside the second raised portion, and adjacent to the second raised portion.
42. The method of forming a bulk acoustic wave resonator device according to claim 41, wherein the shape of the surround type groove comprises: circular, elliptical, or polygonal.
43. The method of forming a bulk acoustic wave resonator device according to claim 24, further comprising: forming a third dielectric portion on the first side and in contact with the first electrode layer; forming a surrounding type groove in the third dielectric portion, inside the resonance region, inside the first raised portion, and adjacent to the first raised portion.
44. The method of forming a bulk acoustic wave resonator device according to claim 43, wherein the shape of the surround-type groove comprises: circular, elliptical, or polygonal.
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