CN115765675A - Bulk acoustic wave resonator, filter, and electronic device including gap electrode - Google Patents
Bulk acoustic wave resonator, filter, and electronic device including gap electrode Download PDFInfo
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Images
Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/13—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
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- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
The invention relates to a bulk acoustic wave resonator comprising: a substrate; a bottom electrode; a top electrode; an acoustic mirror; and a piezoelectric layer, wherein: the bottom electrode is a gap electrode comprising a gap layer, the gap layer forms the acoustic mirror, and the overlapping area of the top electrode, the bottom electrode, the piezoelectric layer and the acoustic mirror in the thickness direction of the resonator defines the effective area of the resonator; the resonator further includes a first seed layer, at least a portion of the first seed layer defining an upper boundary of the gap layer; at the electrode connecting end of the bottom electrode, a first distance a exists between the edge of the first seed layer and the edge of the effective area in the horizontal direction, at the non-electrode connecting end of the bottom electrode, a second distance b exists between the edge of the first seed layer and the edge of the effective area in the horizontal direction, wherein the value of a and/or b is not less than-2.0 μm. The invention also relates to a filter and an electronic device.
Description
Technical Field
Embodiments of the present invention relate to the field of semiconductors, and more particularly, to a bulk acoustic wave resonator including a gap electrode, a filter having the resonator, and an electronic device.
Background
Electronic devices have been widely used as basic elements of electronic equipment, and their application range includes mobile phones, automobiles, home electric appliances, and the like. In addition, technologies such as artificial intelligence, internet of things, 5G communication and the like which will change the world in the future still need to rely on electronic devices as a foundation.
Film Bulk Acoustic Resonator (FBAR, also called Bulk Acoustic Resonator, BAW for short) is playing an important role in the communication field as an important member of piezoelectric devices, especially FBAR filters have increasingly large market share in the field of radio frequency filters, FBARs have excellent characteristics of small size, high resonance frequency, high quality factor, large power capacity, good roll-off effect and the like, the filters gradually replace traditional Surface Acoustic Wave (SAW) filters and ceramic filters, play a great role in the radio frequency field of wireless communication, and the advantage of high sensitivity can also be applied to the sensing fields of biology, physics, medicine and the like.
The structural main body of the film bulk acoustic resonator is a sandwich structure consisting of an electrode, a piezoelectric film and an electrode, namely a layer of piezoelectric material is sandwiched between two metal electrode layers. By inputting a sinusoidal signal between the two electrodes, the FBAR converts the input electrical signal into mechanical resonance using the inverse piezoelectric effect, and converts the mechanical resonance into an electrical signal to be output using the piezoelectric effect.
For the bulk acoustic wave resonator, a form in which the bottom electrode is provided to include a multilayer electrode may be adopted. Fig. 1 is a schematic top view of a resonator, and fig. 2 is a cross-sectional view of a resonator in the prior art taken along line AOA' in fig. 1. As shown in fig. 2, the resonator comprises a substrate 1, a seed layer 2, a bottom electrode layer 3, a seed layer 4, an acoustic mirror 5, a bottom electrode layer 6, a piezoelectric layer 7, a top electrode 8, a passivation layer or process layer 9. In fig. 2, the bottom electrode is a gap electrode, i.e. a gap layer is included therein, which forms the acoustic mirror 5 of the resonator.
In the manufacture of the resonator shown in fig. 2, the acoustic mirror 5 is typically formed by first forming a sacrificial layer of material and then etching or releasing it to form the acoustic mirror. But usually the sacrificial layer material (e.g. PSG) will significantly affect the lattice structure of the electrode material (e.g. molybdenum) deposited thereon and indirectly the lattice structure of the piezoelectric layer material (e.g. aluminum nitride) deposited on the surface of said electrode, thereby leading first of all to a significant drop-off of the resonator parallel impedance Rp. In the resonator structure shown in fig. 2, that is, when the bottom electrode is a gap electrode, when there is no seed layer on the sacrificial layer, the lattice structures of the electrode above the bottom electrode and the piezoelectric layer are affected by the sacrificial layer, so that the parallel resistance Rp of the resonator structure shown in fig. 2 may drop significantly. Secondly, the change in the lattice structure of the piezoelectric layer, which is affected by the sacrificial layer, affects the resonator electromechanical coupling coefficient kt. Furthermore, it is also desirable in the prior art to provide a solution to prevent a significant drop in the value of Rp during adjustment of the value of Kt, thereby degrading the performance of the resonator.
Disclosure of Invention
The present invention is proposed to solve at least one aspect of the above technical problems.
According to an aspect of an embodiment of the present invention, there is provided a bulk acoustic wave resonator including:
a substrate;
a bottom electrode;
a top electrode;
an acoustic mirror; and
a piezoelectric layer is provided on the substrate,
wherein:
the bottom electrode is a gap electrode comprising a gap layer, the gap layer forms the acoustic mirror, and the overlapping area of the top electrode, the bottom electrode, the piezoelectric layer and the acoustic mirror in the thickness direction of the resonator defines the effective area of the resonator;
the resonator further includes a first seed layer, at least a portion of the first seed layer defining an upper boundary of the gap layer;
and at the electrode connecting end of the bottom electrode, a first distance a exists between the edge of the first seed layer and the edge of the active area in the horizontal direction, and at the non-electrode connecting end of the bottom electrode, a second distance b exists between the edge of the first seed layer and the edge of the active area in the horizontal direction, wherein the value of a and/or b is not less than-2.0 μm.
Embodiments of the present invention also relate to a filter comprising the above bulk acoustic wave resonator.
Embodiments of the invention also relate to an electronic device comprising a filter or resonator as described above.
Drawings
These and other features and advantages of the various embodiments of the disclosed invention will be better understood from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate like parts throughout, and in which:
FIG. 1 is a schematic top view of a bulk acoustic wave resonator;
FIG. 2 is a schematic cross-sectional view of a known bulk acoustic wave resonator taken along line AOA' of FIG. 1;
fig. 3 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention along the line AOA' in fig. 1;
fig. 4 is a schematic cross-sectional view of a bulk acoustic wave resonator according to yet another exemplary embodiment of the present invention along the line AOA' in fig. 1;
FIG. 5 is a schematic diagram of the ratio of the effective area occupied by the seed layer on the upper side of the acoustic mirror to the effective area and the electromechanical coupling coefficient kt of the resonator, where the abscissa is the ratio P of B/A and the ordinate is the corresponding electromechanical coupling coefficient kt, where A is the area of the effective area and B is the area of the effective area occupied by the seed layer on the upper side of the acoustic mirror;
fig. 6 is a schematic diagram of the effect of the dimensions a and b in fig. 3 and 4 on the performance of the resonator under the same conditions, with the abscissa being a (default a = b) and the ordinate being the proportion of the parallel impedance Rp of the resonator at a =2 μm for a being the other value;
fig. 7 is a schematic cross-sectional view of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention, along the line AOA' in fig. 1, wherein the resonator is provided with an acoustic mismatch structure.
Detailed Description
The technical scheme of the invention is further specifically described by the following embodiments and the accompanying drawings. In the specification, the same or similar reference numerals denote the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the general inventive concept of the present invention and should not be construed as limiting the invention. Some, but not all embodiments of the invention are described. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.
First, the reference numerals in FIGS. 1 to 7 of the present invention are explained as follows:
1: substrate, and the optional material is monocrystalline silicon, gallium nitride, gallium arsenide, sapphire, quartz, silicon carbide, diamond and the like.
2: the seed layer is made of materials such as aluminum nitride, zinc oxide, PZT and the like and contains rare earth element doping materials with certain atomic ratios of the materials. In the present invention, the seed layer 2 may not be provided.
3: the bottom electrode layer is made of molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or their alloys.
4: the seed layer is made of materials such as aluminum nitride, zinc oxide, PZT and the like and contains rare earth element doping materials with certain atomic ratios of the materials. In the present invention, the seed layer 4 may not be provided.
5: the acoustic mirror can be a cavity, and a Bragg reflection layer and other equivalent forms can also be adopted. The embodiment of the present invention shown employs a void layer disposed in the bottom electrode.
6: the bottom electrode layer (including electrode pins) is made of molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium, or a combination or alloy thereof.
7: a piezoelectric layer, which may be a single crystal piezoelectric material, optionally, such as: materials such as single crystal aluminum nitride, single crystal gallium nitride, single crystal lithium niobate, single crystal lead zirconate titanate (PZT), single crystal potassium niobate, single crystal quartz film, or single crystal lithium tantalate; it may also be a polycrystalline piezoelectric material (corresponding to a single crystal, a non-single crystal material), optionally, a polycrystalline aluminum nitride, zinc oxide, PZT, etc., and may also be a rare earth element doped material containing a certain atomic ratio of the above materials, for example, a doped aluminum nitride containing at least one rare earth element, such as scandium (Sc), yttrium (Y), magnesium (Mg), titanium (Ti), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), etc.
8: the top electrode (including electrode pin) is made of molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or their alloys. The top and bottom electrode materials are typically the same, but may be different.
9: and the passivation layer or the process layer is arranged on the top electrode of the resonator, the process layer can be used as a mass adjusting load or the passivation layer, and the material of the process layer can be dielectric material such as silicon dioxide, aluminum nitride, silicon nitride and the like. In the present invention, the passivation layer or the process layer 9 may not be provided.
10: the seed layer can be selected from materials such as aluminum nitride, zinc oxide, PZT and the like and contains rare earth element doping materials with certain atomic ratios of the materials.
11: bump layer above piezoelectric layer: the material can be selected from molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or the composition or alloy of the above metals. Alternatively, the bump layer 11 may be non-metallic.
12: and the recess forming structure layer is used for forming a recess structure serving as an acoustic impedance unmatched structure, and the material of the recess forming structure layer can be selected from molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composition of the metals or an alloy thereof and the like. Alternatively, the recess-forming structural layer 12 may be made of a non-metal.
13: a cantilever cavity or a bridge cavity.
In the present invention, a seed layer 10 is provided over the acoustic mirror 5, the seed layer 10 defining at least a portion of the upper boundary of the acoustic mirror, and the position of the edge of the seed layer 10 is selected to reduce the adverse effect of the sacrificial layer on the crystal orientation of the structure above it. A bulk acoustic wave resonator according to the present invention is exemplarily described below with reference to fig. 3 to 7.
Fig. 3 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention, taken along line AOA' in fig. 1. As shown in fig. 3, the resonator according to an exemplary embodiment of the present invention comprises a substrate 1, a seed layer 2, a bottom electrode layer 3, a seed layer 4, an acoustic mirror 5, a bottom electrode layer 6, a piezoelectric layer 7, a top electrode 8, a passivation layer or process layer 9. In fig. 3, the bottom electrode is a gap electrode, i.e. a gap layer is included therein, which forms the acoustic mirror 5 of the resonator. More specifically, in fig. 3, a seed layer 10 is provided between the acoustic mirror 5 (sacrificial layer) and the bottom electrode layer 6. In fig. 3, the edge of the seed layer 10 in the horizontal direction is outside the active area of the resonator, and specifically, in the cross section shown in fig. 3, a first distance a exists between the edge of the seed layer 10 and the edge of the active area in the horizontal direction at the electrode connection end of the bottom electrode, and a second distance b exists between the edge of the seed layer 10 and the edge of the active area in the horizontal direction at the non-electrode connection end of the bottom electrode. In fig. 3, the values of a and b are both greater than 0.
In the embodiment shown in fig. 3, the adverse effect of the sacrificial layer on the crystal orientation of the structure above the sacrificial layer can be effectively reduced or even isolated based on the edge of the seed layer 10 being outside the effective area.
In the embodiment shown in fig. 3, the lower boundary of the acoustic mirror 5 is defined by the seed layer 4, while the edge of the seed layer 10 is located outside the edge of the seed layer 4 in the horizontal direction. As mentioned before, the seed layer 4 may also not be provided.
Fig. 4 is a schematic cross-sectional view of a bulk acoustic wave resonator according to yet another embodiment of the present invention, taken along the line AOA' in fig. 1. As shown in fig. 4, the seed layer 10 is in the horizontal direction, and the edge thereof is inside the effective area. At this time, the values of a and b in fig. 4 are negative values. In the present invention, when the edge of the seed layer 10 exceeds the effective area in the horizontal direction, the corresponding values of a and b are positive, and vice versa.
As is clear from fig. 3 and 4, in the present invention, the values of a and b may be positive or negative. However, in the structure shown in fig. 4, i.e., when a or b is smaller than 0, i.e., when the boundary of the seed layer 10 is inside the active region, the acoustic impedance of the region corresponding to a or b is smaller than that of the main resonator region d. Therefore, the region corresponding to a or b becomes a buffer region for energy leakage from the main resonator region d, so that energy leakage from the main resonator region d is facilitated, and the Q value of the resonator in the structure shown in fig. 4 is lowered as compared with the structure shown in fig. 3. Therefore, in order to prevent the Q value of the resonator from being unnecessarily lowered too much, it is necessary to limit the values of a and b in the structure shown in fig. 4 to a suitable range.
Fig. 6 is a schematic diagram showing the influence of the dimensions a and b on the performance of the resonator in fig. 3 and 4 under the same conditions, wherein the abscissa is a (default a = b), the ordinate is the proportion of the parallel impedance Rp of the resonator when a is a =2 μm when a is other values, and in fig. 6, none of the abscissa indicates that the seed layer 10 is not provided, and the other values are values of a (in μm). As can be seen from fig. 6, the parallel resonance impedance Rp for the resonator where the seed layer 10 is not provided is 59% of the parallel resonance impedance Rp of the resonator where the seed layer 10 is provided, and Rp also decreases stepwise as the value of a becomes smaller.
Although the relationship between the value a and Rp shown in fig. 6 is based on the structures shown in fig. 3 and fig. 4, and the values of a and b are equal, the values of a and b may also be different, for example, one of a and b may be a negative value, the other may be a positive value, or a and b may be other values, and a relationship similar to that shown in fig. 6 may also be obtained.
In order to ensure the performance of the resonator, the values of a and b corresponding to the seed layer 10 may be limited, for example, the values of a and b may be not less than-1.5 μm, and in this case, the Rp of the corresponding resonator is at least about 80% of the Rp when the values of a and b are not less than 0.
Specifically, as shown in fig. 5, as the values of a and b increase, the Kt value of the resonator increases, and thus, in practical applications, the Kt value of the resonator can be adjusted by selecting the values of a and b. However, the values of a and b cannot be too small, and as shown in fig. 6, it can be seen that as the value of a becomes smaller, the value of Rp gradually decreases, which can significantly degrade the performance of the resonator. Therefore, in the case where the Kt value of the resonator can be adjusted by the values of a and b, it is also desirable that the values of a and b be selected to have an effect on the performance of the resonator within a reasonable range. Based on the above, in one embodiment of the invention, the value of a and/or b may be not less than-2.0 μm, see fig. 6, which is advantageous for the resonator to obtain a higher Rp value.
In one embodiment of the invention, the values of a and b may be less than 1.0 μm. This is advantageous both for obtaining the advantages of a structure such as that shown in fig. 3 and for reducing the adverse effect of the seed layer 10 on the electrical connection performance between the two bottom electrode layers, i.e. for increasing the conductivity of the bottom electrode.
Fig. 5 is a schematic relationship diagram of the ratio of the effective area occupied by the seed layer on the upper side of the acoustic mirror to the effective area and the electromechanical coupling coefficient kt of the resonator, where the abscissa is the ratio P of B/a and the ordinate is the corresponding electromechanical coupling coefficient kt, where a is the area of the effective area and B is the area of the effective area occupied by the seed layer on the upper side of the acoustic mirror. As can be seen from fig. 5, as the P value increases, the electromechanical coupling coefficient kt increases.
Although the relationship diagram between the ratio P and Kt shown in fig. 5 is based on the structure of fig. 4 in which the values of a and b are negative values, one of a and b may be negative, and a relationship diagram similar to that shown in fig. 5 may also be obtained.
In fig. 5, a ratio P of 1 may correspond to the structure shown in fig. 3, or other structures where the seed layer 10 occupies the entire area of the active area.
In one embodiment of the invention, the ratio P is chosen to be not less than 0.5, and in a further embodiment not less than 0.8.
In the embodiments shown in fig. 3 and 4, the resonators are not provided with acoustic impedance mismatches along the active area. However, as shown in FIG. 7, an acoustic impedance mismatch structure may also be provided. Fig. 7 is a schematic sectional view of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention, taken along line AOA' in fig. 1, in which the resonator is provided with an acoustic mismatched structure, specifically, a void or cavity 13 under a suspended wing structure of a top electrode non-electrode connection end and a void or cavity 13 under a bridge portion of an electrode connection end of a top electrode, a recessed structure formed by a recess-forming structural layer 12, and the like. It should be noted that the acoustic impedance mismatch structure shown in fig. 7 is merely exemplary, and other forms of acoustic impedance mismatch structures, such as the raised structure 11 shown in fig. 7, may be provided, and still fall within the scope of the present invention.
Referring to fig. 7, a, b are shown. The selection of the values of a and b shown in fig. 7 and the ratio of the area of the active area occupied by the seed layer 10 to the area of the active area are also applicable to the above description with reference to fig. 3 to 6, and will not be described herein again.
It is to be noted that, in the present invention, each numerical range, except when explicitly indicated as not including the end points, can be either the end points or the median of each numerical range, and all fall within the scope of the present invention.
In the present invention, the upper and lower are with respect to the bottom surface of the base of the resonator, and with respect to one component, the side thereof close to the bottom surface is the lower side, and the side thereof far from the bottom surface is the upper side.
In the present invention, the inner and outer are in the horizontal direction or the radial direction with respect to the center of the effective area (i.e., the effective area center) of the resonator (the overlapping area of the piezoelectric layer, the top electrode, the bottom electrode, and the acoustic mirror in the thickness direction of the resonator constitutes the effective area), the side or end of a member close to the center is the inner side or the inner end, and the side or end of the member away from the center is the outer side or the outer end. For a reference position, being inside of the position means being between the position and the center in a horizontal or radial direction, and being outside of the position means being further away from the center in a horizontal or radial direction than the position.
As can be appreciated by those skilled in the art, the bulk acoustic wave resonator according to the present invention may be used to form a filter or an electronic device.
The electronic device includes, but is not limited to, intermediate products such as a radio frequency front end and a filtering and amplifying module, and terminal products such as a mobile phone, WIFI and an unmanned aerial vehicle.
Based on the above, the invention provides the following technical scheme:
1. a bulk acoustic wave resonator comprising:
a substrate;
a bottom electrode;
a top electrode;
an acoustic mirror; and
a piezoelectric layer is formed on the substrate,
wherein:
the bottom electrode is a gap electrode comprising a gap layer, the gap layer forms the acoustic mirror, and the overlapping area of the top electrode, the bottom electrode, the piezoelectric layer and the acoustic mirror in the thickness direction of the resonator defines the effective area of the resonator;
the resonator further includes a first seed layer, at least a portion of the first seed layer defining an upper boundary of the gap layer;
and at the electrode connecting end of the bottom electrode, a first distance a exists between the edge of the first seed layer and the edge of the active area in the horizontal direction, and at the non-electrode connecting end of the bottom electrode, a second distance b exists between the edge of the first seed layer and the edge of the active area in the horizontal direction, wherein the value of a and/or b is not less than-2.0 μm.
2. The resonator of claim 1, wherein:
the value of a and/or b is not less than-1.5. Mu.m.
3. The resonator of claim 2, wherein:
the value of a and/or b is less than 1.0. Mu.m.
4. The resonator of claim 3, wherein:
in the horizontal direction, the edges of the first seed layer are all positioned outside the effective area.
5. The resonator of claim 1, wherein:
the edge of the first seed layer is located outside the acoustic mirror in the horizontal direction.
6. The resonator of claim 1, wherein:
the resonator is also provided with an acoustic impedance mismatch structure disposed along the active area of the resonator.
7. The resonator of claim 1, wherein:
the resonator also includes a second seed layer defining a lower boundary of the acoustic mirror.
8. The resonator of claim 7, wherein:
in the horizontal direction, at the non-electrode connecting end and/or the electrode connecting end of the bottom electrode, the edge of the first seed layer is positioned outside the edge of the second seed layer.
9. The resonator of any one of claims 1-8, wherein:
the area of the effective region is A, the overlapping area of the first seed layer and the effective region is B, and the ratio P of B/A is not less than 0.5.
10. The resonator of claim 9, wherein:
the value of P is not less than 0.8.
11. A filter comprising a resonator according to any of claims 1-10.
12. An electronic device comprising a filter according to 11 or a resonator according to any of claims 1-10.
Although embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.
Claims (12)
1. A bulk acoustic wave resonator comprising:
a substrate;
a bottom electrode;
a top electrode;
an acoustic mirror; and
a piezoelectric layer is formed on the substrate,
wherein:
the bottom electrode is a gap electrode comprising a gap layer, the gap layer forms the acoustic mirror, and the overlapping area of the top electrode, the bottom electrode, the piezoelectric layer and the acoustic mirror in the thickness direction of the resonator defines the effective area of the resonator;
the resonator further includes a first seed layer, at least a portion of the first seed layer defining an upper boundary of the gap layer;
and at the electrode connecting end of the bottom electrode, a first distance a exists between the edge of the first seed layer and the edge of the active area in the horizontal direction, and at the non-electrode connecting end of the bottom electrode, a second distance b exists between the edge of the first seed layer and the edge of the active area in the horizontal direction, wherein the value of a and/or b is not less than-2.0 μm.
2. The resonator of claim 1, wherein:
the value of a and/or b is not less than-1.5 μm.
3. The resonator of claim 2, wherein:
the value of a and/or b is less than 1.0. Mu.m.
4. The resonator of claim 3, wherein:
in the horizontal direction, the edges of the first seed layer are positioned outside the effective area.
5. The resonator of claim 1, wherein:
the edge of the first seed layer is located outside the acoustic mirror in the horizontal direction.
6. The resonator of claim 1, wherein:
the resonator is also provided with an acoustic impedance mismatch structure disposed along the active area of the resonator.
7. The resonator of claim 1, wherein:
the resonator also includes a second seed layer defining a lower boundary of the acoustic mirror.
8. The resonator of claim 7, wherein:
in the horizontal direction, at the non-electrode connecting end and/or the electrode connecting end of the bottom electrode, the edge of the first seed layer is positioned outside the edge of the second seed layer.
9. The resonator of any of claims 1-8, wherein:
the area of the effective area is A, the overlapping area of the first seed layer and the effective area is B, and the ratio P of B/A is not less than 0.5.
10. The resonator of claim 9, wherein:
the value of P is not less than 0.8.
11. A filter comprising a resonator according to any of claims 1-10.
12. An electronic device comprising a filter according to claim 11 or a resonator according to any of claims 1-10.
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| CN202111034257.5A CN115765675A (en) | 2021-09-03 | 2021-09-03 | Bulk acoustic wave resonator, filter, and electronic device including gap electrode |
| PCT/CN2022/116049 WO2023030359A1 (en) | 2021-09-03 | 2022-08-31 | Bulk acoustic resonator comprising gap electrode, filter and electronic device |
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| CN202111034257.5A CN115765675A (en) | 2021-09-03 | 2021-09-03 | Bulk acoustic wave resonator, filter, and electronic device including gap electrode |
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| WO2024021844A1 (en) * | 2022-07-28 | 2024-02-01 | 诺思(天津)微系统有限责任公司 | Bulk acoustic resonator and manufacturing method therefor, filter, and electronic device |
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| KR101598294B1 (en) * | 2014-09-15 | 2016-02-26 | 삼성전기주식회사 | Acoustic resonator and manufacturing method thereof |
| CN111245393B (en) * | 2019-12-04 | 2021-08-10 | 诺思(天津)微系统有限责任公司 | Bulk acoustic wave resonator, method of manufacturing the same, filter, and electronic apparatus |
| CN111262540A (en) * | 2019-12-31 | 2020-06-09 | 诺思(天津)微系统有限责任公司 | Bulk acoustic wave resonator, method of manufacturing the same, filter, and electronic apparatus |
| CN111082777B (en) * | 2019-12-31 | 2021-03-12 | 诺思(天津)微系统有限责任公司 | Bulk acoustic wave resonator with gap electrode as bottom electrode, filter and electronic device |
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| WO2024021844A1 (en) * | 2022-07-28 | 2024-02-01 | 诺思(天津)微系统有限责任公司 | Bulk acoustic resonator and manufacturing method therefor, filter, and electronic device |
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