Bulk acoustic wave resonator, filter and electronic device with asymmetric electrode thicknesses

Abstract

The present invention relates to a bulk acoustic wave resonator, comprising: a substrate; an acoustic mirror; a sandwich structure composed of a top electrode, a piezoelectric layer, and a bottom electrode, an overlapping portion of the top electrode, the piezoelectric layer, the bottom electrode, and the acoustic mirror in a thickness direction of the resonator forming an effective area; and a reinforcing structure on one side of the sandwich structure, the reinforcing structure for reflecting acoustic waves to improve a Q value, wherein: a thickness of an electrode on the one side of the sandwich structure is smaller than a thickness of an electrode on the other side of the sandwich structure. The present invention also relates to a filter and an electronic device having the same.

Description

Technical Field

[0001] Embodiments of the present invention relate to the semiconductor field, and more particularly to a bulk acoustic wave resonator, a filter having the resonator, and an electronic device having the resonator or filter. Background Technology

[0002] Thin-film bulk resonators, fabricated using the longitudinal resonance of piezoelectric thin films in the thickness direction, have become a viable alternative to surface acoustic wave (SAW) devices and quartz crystal resonators in mobile communications and high-speed serial data applications. RF front-end bulk wave filters / duplexers offer superior filtering characteristics, such as low insertion loss, a steep transition band, high power capacity, and strong electrostatic discharge (ESD) immunity. High-frequency thin-film bulk resonators with ultra-low frequency temperature drift exhibit low phase noise, low power consumption, and a wide bandwidth modulation range. Furthermore, these miniature thin-film resonators are fabricated on silicon substrates using CMOS-compatible processes, which reduces unit cost and facilitates eventual integration with CMOS circuits.

[0003] Figure 1a and Figure 1b The bulk acoustic resonator structure shown is as follows: It has a substrate P100; an acoustic mirror P200 embedded in the substrate or located on the substrate surface, the acoustic mirror P200 may include a cavity, a Bragg reflector layer, or other equivalent structures capable of reflecting sound waves; a bottom electrode P300 covering the acoustic mirror structure and part of the substrate; a piezoelectric thin film layer P400 covering the bottom electrode and part of the substrate; and a top electrode P500 located on the piezoelectric layer and covering part of the piezoelectric layer. The lateral overlap of the top electrode P500, piezoelectric layer P400, bottom electrode P300, and cavity P200 defines the effective acoustic region AR of the bulk acoustic resonator. Typically, the bottom electrode BE and top electrode TE also have... Figure 1a The electrode pins P301 and P501 shown are... Figure 1b (Not shown in the image).

[0004] The top or bottom electrode surface also has a reinforcing structure P600. Figure 1b (P600 in the diagram is for illustrative purposes only and does not represent the exact structure). The enhancement structure may include a protrusion structure for reflecting sound waves that propagate laterally to the boundary of the effective region, thereby improving the Q value of the resonator.

[0005] also, Figure 1a and Figure 1b The text also omits the adjustment process layer that is usually covered on the functional layers of the resonator, such as P500 and P400. The function of this type of process layer is usually to protect the resonator from external moisture and oxygen corrosion, or to adjust the performance parameters of the resonator (such as frequency).

[0006] However, although the Q value can be improved by setting a reinforcing structure to reflect the laterally propagating acoustic wave, there is a demand for further enhancing the acoustic wave reflection function in reality. SUMMARY

[0007] To alleviate or solve at least one aspect of the above problems using the prior art, the present application is proposed.

[0008] According to an aspect of an embodiment of the present application, a bulk acoustic wave resonator is proposed, comprising: a substrate; an acoustic mirror; a sandwich structure composed of a top electrode, a piezoelectric layer and a bottom electrode, an overlapping portion of the top electrode, the piezoelectric layer and the bottom electrode in a thickness direction of the resonator forming an effective area; a reinforcing structure provided at one side of the sandwich structure, wherein: a thickness of an electrode located at the one side of the sandwich structure is less than a thickness of an electrode located at the other side of the sandwich structure.

[0009] Optionally, a ratio of the thickness of the electrode located at the other side of the sandwich structure to the thickness of the electrode located at the one side of the sandwich structure is in a range of 1.1-2.5. Further, the ratio of the thickness of the electrode located at the other side of the sandwich structure to the thickness of the electrode located at the one side of the sandwich structure is in a range of 1.5-2.25.

[0010] An embodiment of the present application also relates to a filter comprising the above-mentioned bulk acoustic wave resonator.

[0011] An embodiment of the present application further relates to an electronic device comprising the above-mentioned bulk acoustic wave resonator or the above-mentioned filter. BRIEF DESCRIPTION OF DRAWINGS

[0012] The following description and drawings can better help understand these and other features and advantages of the various embodiments disclosed of the present application, in which the same reference signs always designate the same parts, in which:

[0013] Figure 1a is a schematic top view of a bulk acoustic wave resonator in the prior art;

[0014] Figure 1b is a schematic cross-sectional view taken along the AOA' line in Figure 1a

[0015] Figure 2 is a schematic view of the top electrode and the bottom electrode of the sandwich structure of the resonator in the prior art having the same thickness;

[0016] Figure 3 is a graph of the relationship between the electromechanical coupling coefficient of the sandwich structure of the resonator in the prior art and the ratio of the two electrode thicknesses;

[0017] Figure 4 ​Schematic diagram of a sandwich structure of a resonator according to an exemplary embodiment of the present application;

[0018] Figure 5a Schematic diagram of a resonator according to an exemplary embodiment of the present application;

[0019] Figure 5b Exemplary schematic diagram of a reinforcing structure;

[0020] Figure 5c Exemplary schematic diagram of an alternative reinforcing structure;

[0021] Figure 5d Schematic diagram of simulation results based on the reinforcing structure in Figure 5c

[0022] Figure 5e Schematic diagram of simulation results based on the reinforcing structure in Figure 5c

[0023] Schematic diagram of a resonator according to an exemplary embodiment of the present application; Figure 6

[0024] Schematic diagram of a resonator according to an exemplary embodiment of the present application; Figure 7

[0025] Schematic diagram of a resonator according to an exemplary embodiment of the present application; Figure 8

[0026] Exemplary schematic diagram of a parallel resonant impedance of a resonator versus width of a reinforcing structure; Figure 9

[0027] Schematic diagram of dispersion curve of S1 mode; Figure 10

[0028] Schematic diagram of a resonator according to an exemplary embodiment of the present application, wherein a convex reinforcing structure and a concave structure are shown. Figure 11 DETAILED DESCRIPTION

[0029] The technical solutions of the present application will be further described below in conjunction with the accompanying drawings. In the description, identical or similar reference numerals indicate identical or similar components. The following description of the embodiments of the present application with reference to the accompanying drawings is intended to explain the general inventive concept of the present application, and should not be construed as a limitation of the present application.

[0030] The present application will be described below by way of example with reference to the accompanying drawings.

[0031] Figure 2 Schematic diagram of top and bottom electrodes of a sandwich structure of a resonator in the prior art having equal thicknesses;​​Figure 4 A schematic diagram of a sandwich structure of a resonator according to an exemplary embodiment of the present application.

[0032] As shown in Figure 2 and Figure 4 , the sandwich structure comprises a top electrode E1, a piezoelectric layer E4, a bottom electrode E2, and a reinforcing structure E3 disposed at the end of the top electrode E1. The reinforcing structure is used to reflect acoustic waves propagating laterally to the boundary of the effective area, thereby improving the Q value of the resonator.

[0033] Figure 4 Compared with Figure 2 , the difference is that the thickness of the top electrode E1 is reduced, while the thickness of the bottom electrode E2 is increased. As can also be seen from Figure 4 , the reinforcing structure E3 is disposed at the side of the electrode with reduced thickness.

[0034] If it is required to Figure 4 maintain the resonator frequency unchanged, it is also required that the thickness T1+T2+T0 of the sandwich structure in Figure 2 be the same as the thickness T1+T2+T0 of the sandwich structure in Figure 2 . Figure 4

[0035] Figure 3 A graph showing the relationship between the electromechanical coupling coefficient (kt 2 ) of the sandwich structure of the resonator in the prior art and the ratio r of the thickness of the two electrodes. Figure 3 A graph showing the experimental and simulation results of the inventor, under the condition that the thickness of the top electrode and the bottom electrode is the same (i.e. the ratio r of the thickness of the electrodes is 1), the sandwich structure has the maximum electromechanical coupling coefficient (kt 2 max), while the electrodes with unequal thicknesses will result in a decrease in the electromechanical coupling coefficient.

[0036] Figure 5a A schematic diagram of a resonator according to an exemplary embodiment A100 of the present application; Figure 5b is an enlarged schematic diagram of the reinforcing structure used in Figure 5a .

[0037] The resonator structure of the embodiment A100 comprises a substrate 100, an acoustic mirror (cavity) 110, a bottom electrode 120, a piezoelectric layer 130, a top electrode 140, and a reinforcing structure 150 at the edge of the top electrode.

[0038] Optionally, the resonator surface can also be covered with other process layers 160 according to specific needs, such as a passivation layer for preventing moisture and suppressing oxidation, etc. (the process layers are also applicable to subsequent embodiments, and are not shown in subsequent diagrams).

[0039] ​In embodiment A100, the thickness of the bottom electrode is greater than the thickness of the top electrode, and the ratio of the bottom electrode thickness to the top electrode thickness ranges from 1.1 to 2.5, with a further range of 1.5 to 2.25. It should be noted that this requirement includes the case where the process layer 160 is taken into consideration. Subsequent embodiments follow a similar approach; that is, when a process layer is provided, the thickness ratio of the electrode on the un-thickened side to the electrode on the thickened side still satisfies the aforementioned ratio range even when the thickness of the process layer is taken into account. The ratio of the electrode thickness on the other side of the sandwich structure to the electrode thickness on one side of the sandwich structure can be 1.1, 1.3, 2.0, 2.25, 2.5, etc.

[0040] The bottom electrode 120 can be made of a single-layer metal material or alloy, or a multi-layer composite material.

[0041] When both the top electrode and the bottom electrode are single-layer materials, the metal materials used for the top electrode and the bottom electrode can be the same or different.

[0042] Figure 5a The reinforcement structure 150 is only illustrative and does not represent a specific structure, as will be the case in subsequent embodiments.

[0043] Figure 5b One type of reinforcement structure shown includes a blocky protrusion B0 located on electrode E099, wherein the material of the blocky protrusion B0 may be the same as or different from that of electrode E099. Figure 5b In the figure, the thickness is HB0, the width is DB0, and the thickness of electrode E099 is HE0. In optional embodiments, the width DB0 of the block protrusion B0 is in the range of 0.5 micrometers to 7 micrometers, for example, 0.5 micrometers, 1 micrometer, 2 micrometers, 5 micrometers, 7 micrometers, etc.; optionally, DB0 is in the range of 0.5 micrometers to 2 micrometers, and may also be 1 / 4 of the transverse Lamb wave wavelength λ of S1 mode, or an odd multiple of 1 / 4 of the Lamb wave wavelength λ.

[0044] The following is a reference to the appendix. Figure 10 Describe the S1 mode. For example... Figure 10 As shown, when the bulk acoustic resonator is working, a large number of vibrations are generated in the sandwich structure. If these vibrations are plotted as dispersion curves according to the relationship between their frequency (f) and wavenumber (k), curves for multiple modes can be obtained. The curve for one mode is called the S1 mode (the curves for the other modes are not shown in the diagram). Figure 10 (as shown in the image), it has Figure 10 The dispersion curve shown is shaped as follows, where the horizontal axis represents the wave number and the vertical axis represents the vibrational frequency. The vibrational frequency is the parallel resonant frequency f. p When the wave number is k, p The wavelength λ of the S1 mode is defined by the following equation:

[0045]

[0046] In an optional embodiment, the thickness HE0 of the block protrusion B0 is [missing information]. Within a range, for example, it can be and wait.

[0047] like Figure 5c As shown, the electrode E300 of the airfoil structure has a protruding portion, defined as the area within the dashed region B2, with a width defined as DG3. The width of the airfoil portion is defined as AW2, and its thickness as HG3. The thickness of electrode E300 is HE3, and there is a gap G4 below the airfoil structure. The specific reinforcing structure 150 is not limited to... Figure 5b-5c The form in the diagram can also be any other enhancement structure that is readily conceived by those skilled in the art.

[0048] Figure 9 This is a schematic diagram illustrating an exemplary embodiment of the relationship between the parallel resonant impedance of a resonator and the width of the reinforcement structure, where: the vertical axis represents the parallel resonant impedance of the resonator, the horizontal axis represents the width of the reinforcement structure, the triangular broken line shows the parallel resonant impedance after the electrode thickness is reduced (i.e., the thicknesses of the top electrode and the bottom electrode are different), and the circular broken line shows the parallel resonant impedance when the ratio of the electrode thicknesses is 1.

[0049] from Figure 9 The graph showing the relationship between the parallel resonant impedance and the width of the reinforcement structure reveals that the parallel resonant impedance using an asymmetrical structure (i.e., two electrodes of different thicknesses) is significantly higher than that of a symmetrical structure (i.e., two electrodes of the same thickness) over the range of reinforcement structure width variation (where the two curves only overlap in a small range). Figure 9 As shown, when the width of the reinforcement structure is in the range of 0.5 micrometers to 1.25 micrometers, or not less than 1.5 micrometers, the parallel resonant impedance is significantly improved compared to a symmetrical arrangement structure with the same electrode thickness.

[0050] Figure 5d For Figure 5c The first simulation result diagram of the enhanced structure is shown, where: the simulation conditions are set as follows: DG3 = 1 μm, AW2 = 1 μm. The horizontal axis represents the ratio of the thickness of the non-reinforced side electrode to the thickness of the reinforced side electrode, and the vertical axis represents the parallel resonant impedance.

[0051] Figure 5e For Figure 5c The second simulation result diagram of the enhanced structure is shown, where: the simulation conditions are set as follows: DG3 = 1 μm, AW2 = 1 μm. The abscissa is the ratio of the thickness of the electrode on the non-enhanced structure side to the thickness of the electrode on the enhanced structure side, and the ordinate is the parallel resonant impedance.

[0052] Figure 5d With Figure 5e the example, when the width of the enhanced structure is constant, the curves of the change of the parallel resonant impedance are shown when the ratio of the electrode thickness is different.

[0053] Based on Figure 5d and 5e , it can be seen that the trend of the change of the curves is approximately the same only when the thickness of the enhanced structure changes from to .

[0054] The above exemplary description of the enhanced structure is also applicable to other embodiments of the present application.

[0055] Figure 6 is a schematic diagram of a resonator according to another exemplary embodiment A200 of the present application. In Figure 6 , the thickness of the bottom electrode is greater than that of the top electrode. Embodiment A200 differs from embodiment AlOO in that the enhanced structure in embodiment A200 is located on the lower surface of the top electrode. As shown in Figure 6 , the enhanced structure is a protrusion embedded in the piezoelectric layer 230. The enhanced structure can also be a cavity provided in the upper surface of the piezoelectric layer 230 or the lower surface or upper surface of the top electrode 240 (which can or can not be filled with a solid material), or a combination of protrusions and cavities, or other forms.

[0056] Figure 7 is a schematic diagram of a resonator according to another exemplary embodiment A300 of the present application. Embodiment A300 differs from embodiments AlOO and A200 in that in embodiment A300, the bottom electrode is thinner and the enhanced structure is located on the upper surface of the bottom electrode. As shown in Figure 7 , the enhanced structure is a protrusion embedded in the piezoelectric layer 330.

[0057] Figure 8 is a schematic diagram of a resonator according to another exemplary embodiment A400 of the present application. In embodiment A400, the bottom electrode is thinner and the enhanced structure is located on the lower surface of the bottom electrode. As shown in Figure 8 , the enhanced structure is a protrusion protruding into the cavity or the mirror 410.

[0058] Although in the present application, the enhanced structure is provided on the top electrode, the bottom electrode or the piezoelectric layer, for different mirror structures, the enhanced structure can also be provided at other positions in the resonator.

[0059] In the present application, if the thickness of the electrode on one side of the enhancement structure is reduced while the thickness of the electrode on the other side is increased, the reflection performance of the enhancement structure for the transverse propagating acoustic wave can be effectively improved. The reflection performance is mainly reflected in the improvement of the parallel resonance impedance of the resonator by the asymmetric structure, and the larger the parallel resonance impedance, the better the performance of the bulk acoustic wave resonator.

[0060] Based on Figure 3 It can be seen that the use of two electrodes with different thicknesses will result in a decrease in the electromechanical coupling coefficient of the resonator. In order to keep the electromechanical coupling coefficient unchanged, the present application also proposes to dope the piezoelectric layer with elements to compensate for the loss of electromechanical coupling coefficient caused thereby.

[0061] Figure 11 A schematic diagram of a resonator according to an exemplary embodiment A500 of the present application is shown, in which a convex enhancement structure and a recessed structure are shown.

[0062] Based on the asymmetric structure of the electrode thickness, the acoustic wave reflection performance of the convex enhancement structure can be improved, and the Q value of the resonator can be improved, but at the same time the spurious mode noise can also be enhanced. To overcome the above problems, on the basis of the previous embodiment, a'recessed' suppression structure (i.e. a recessed structure) can be added to suppress the above-mentioned spurious mode acoustic waves.

[0063] The depth of the recessed structure can be the same as the thickness of the convex enhancement structure, and the width of the recessed structure can be the same as the width of the convex enhancement structure.

[0064] As Figure 11 shown, the recessed structure 150 is arranged on the inner side of the convex enhancement structure adjacent to the convex enhancement structure.

[0065] Correspondingly, the piezoelectric layer material can be selected from, but is not limited to, aluminum nitride, wherein the doping elements include scandium (preferably), yttrium, magnesium, titanium, or other rare earth elements. The doping atomic fraction ranges from 1% to 40%, and the preferred range is 3% to 20%. The specific atomic fraction can be 1%, 3%, 6%, 20%, 30%, 40%, etc. In addition, zinc oxide, lithium niobate or lead titanate zirconate (PZT) can also be used as the main material of the piezoelectric layer and be doped with the above elements. The above piezoelectric materials are thin films with a thickness of less than 10 microns. The aluminum nitride thin film is in a polycrystalline or single crystal form, and the growth method is thin film sputtering or metal organic chemical vapor deposition (MOCVD).

[0066] The substrate material can be selected from, but is not limited to, single crystal silicon, quartz, gallium arsenide or sapphire, etc.

[0067] Electrode materials include, but are not limited to, molybdenum, ruthenium, gold, magnesium, aluminum, tungsten, titanium, chromium, iridium, osmium, etc., and multi-layered composite materials or alloys of the above metals can also be used.

[0068] Based on the above, the present application proposes the following technical solutions:

[0069] 1. A bulk acoustic wave resonator comprising: a substrate; an acoustic mirror; a sandwich structure composed of a top electrode, a piezoelectric layer, and a bottom electrode, an overlapping portion of the top electrode, the piezoelectric layer, and the bottom electrode in a thickness direction of the resonator forming an effective area; and a reinforcing structure provided on one side of the sandwich structure, wherein a thickness of an electrode located on the one side of the sandwich structure is smaller than a thickness of an electrode located on the other side of the sandwich structure.

[0070] 2. The resonator according to claim 1, wherein the top electrode includes a metal layer and a process layer provided on the metal layer, and a sum of thicknesses of the metal layer and the process layer is the thickness of the top electrode.

[0071] 3. The resonator according to claim 1, wherein the thickness of the top electrode is greater than the thickness of the bottom electrode.

[0072] 4. The resonator according to claim 1, wherein the thickness of the top electrode is smaller than the thickness of the bottom electrode.

[0073] 5. The resonator according to claim 1, wherein a ratio of the thickness of the electrode located on the other side of the sandwich structure to the thickness of the electrode located on the one side of the sandwich structure is in a range of 1.1 to 2.5.

[0074] 6. The resonator according to claim 5, wherein the ratio of the thickness of the electrode located on the other side of the sandwich structure to the thickness of the electrode located on the one side of the sandwich structure is in a range of 1.5 to 2.25.

[0075] 7. The resonator according to claim 1, wherein the reinforcing structure includes a protrusion-type reinforcing structure.

[0076] 8. The resonator according to claim 7, wherein a width of the protrusion-type reinforcing structure is in a range of 0.5 μm to 7 μm.

[0077] 9. The resonator according to claim 8, wherein the width of the protrusion-type reinforcing structure is in a range of 0.5 μm to 2 μm.

[0078] 10. The resonator according to claim 7, wherein the width of the protrusion-type reinforcing structure is 1 / 4 of a S1 mode transverse Lamb wave wavelength, or an odd multiple of 1 / 4 of the Lamb wave wavelength.

[0079] 11. The resonator according to any one of claims 7 to 10, wherein a protrusion thickness of the protrusion-type reinforcing structure is in a range of 0.1 μm to 1 μm.

[0080] 12. The resonator according to claim 11, wherein: the protrusion thickness of the protrusion type reinforcing structure is in a range of

[0081] 13. The resonator according to claim 7, wherein:

[0082] the resonator further comprises a recess structure, the recess structure being disposed adjacent to the protrusion type reinforcing structure on an inner side of the protrusion type reinforcing structure.

[0083] 14. The resonator according to claim 13, wherein:

[0084] the width of the recess structure is in a range of 0.5 micrometers to 7 micrometers; or the width of the recess structure is 1 / 4 of a S1 mode lateral Lamb wave wavelength, or an odd multiple of 1 / 4 of the Lamb wave wavelength.

[0085] 15. The resonator according to claim 14, wherein:

[0086] the width of the recess structure is in a range of 0.5 micrometers to 2 micrometers.

[0087] 16. The resonator according to claim 13 or 14, wherein:

[0088] the depth of the recess structure is in a range of

[0089] 17. The resonator according to claim 16, wherein:

[0090] the depth of the recess structure is in a range of

[0091] 18. The resonator according to any one of claims 1 to 17, wherein: the piezoelectric layer is doped with one or more of the following elements: scandium, yttrium, magnesium, titanium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium; and the atomic fraction of the doping element is in a range of 1% to 40%.

[0092] 19. The resonator according to claim 18, wherein: the atomic fraction of the doping element is in a range of 3% to 20%.

[0093] 20. The resonator according to claim 18 or 19, wherein: the piezoelectric layer is an aluminum nitride piezoelectric layer, a zinc oxide piezoelectric layer, a lithium niobate piezoelectric layer, or a lead zirconate titanate piezoelectric layer.

[0094] Accordingly, the present application also relates to a filter comprising the above-mentioned resonator.

[0095] The application also relates to an electronic device comprising the resonator or filter described above. It should be pointed out that the electronic device herein includes but is not limited to intermediate products such as radio frequency front ends, filter amplification modules, and terminal products such as mobile phones, WIFI, and unmanned aerial vehicles.

[0096] Although the embodiments of the present application have been shown and described, it is to be understood that the embodiments are not limiting and that changes can be made to these embodiments without departing from the principles and spirit of the application, the scope of which is defined by the following claims and their equivalents.

Claims

1. A bulk acoustic resonator, comprising: a substrate; an acoustic mirror; a sandwich structure consisting of a top electrode, a piezoelectric layer and a bottom electrode, an overlapping portion of the top electrode, the piezoelectric layer, the bottom electrode and the acoustic mirror in a thickness direction of the resonator forming an effective area; a reinforcing structure disposed on one side of the sandwich structure, wherein: the top electrode comprises a metal layer and a process layer disposed on the metal layer, a sum of thicknesses of the metal layer and the process layer being a thickness of the top electrode; a thickness of an electrode on the one side of the sandwich structure where the reinforcing structure is disposed is half of a thickness of an electrode on the other side of the sandwich structure in the entire effective area of the resonator, resulting in a decrease of an electromechanical coupling coefficient of the resonator; to avoid the aforementioned decrease of the electromechanical coupling coefficient, the piezoelectric layer is doped with one or more of the following elements: scandium, yttrium, magnesium, titanium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and an atomic fraction of the doping element ranges from 1% to 40%, so that the electromechanical coupling coefficient of the bulk acoustic resonator is unchanged relative to an electromechanical coupling coefficient of a comparative structure with the same thickness of the two electrodes. 2.The resonator of claim 1, wherein: the thickness of the top electrode is greater than the thickness of the bottom electrode. 3.The resonator of claim 1, wherein: the thickness of the top electrode is less than the thickness of the bottom electrode. 4.The resonator of claim 1, wherein: the reinforcing structure comprises a protruding reinforcing structure. 5.The resonator of claim 4, wherein: a width of the protruding reinforcing structure ranges from 0.5 micrometers to 7 micrometers. 6.The resonator of claim 5, wherein: a width of the protruding reinforcing structure ranges from 0.5 micrometers to 2 micrometers. 7.The resonator of claim 4, wherein: the width of the protruding reinforcing structure is 1 / 4 of a S1 mode transverse Lamb wave wavelength, or an odd multiple of 1 / 4 of the Lamb wave wavelength. 8.The resonator of any one of claims 4-7, wherein: The raised thickness of the raised reinforcing structure ranges from 9.The resonator of claim 8, wherein: The convex thickness of the convex type reinforcing structure ranges from 0.1 to 1.5 mm 10.The resonator of claim 4, wherein: the resonator further comprises a recessed structure disposed on an inner side of the protruding reinforcing structure adjacent to the protruding reinforcing structure. 11.The resonator of claim 10, wherein: a width of the recessed structure ranges from 0.5 micrometers to 7 micrometers; or the width of the recessed structure is 1 / 4 of a S1 mode transverse Lamb wave wavelength, or an odd multiple of 1 / 4 of the Lamb wave wavelength. 12.The resonator of claim 11, wherein: a width of the recessed structure ranges from 0.5 micrometers to 2 micrometers. 13.The resonator of claim 10 or 11, wherein: The depth of the recessed structure ranges from 14.The resonator of claim 13, wherein: The depth of the recessed structure ranges from 15.The resonator of claim 1, wherein: the atomic fraction of the doping element ranges from 3% to 20%. 16.The resonator of claim 1, wherein: The piezoelectric layer is an aluminum nitride piezoelectric layer, a zinc oxide piezoelectric layer, a lithium niobate piezoelectric layer, or a lead titanate zirconate piezoelectric layer.

17. A filter comprising: The bulk acoustic wave resonator according to any one of claims 1-16.

18. An electronic device comprising the bulk acoustic wave resonator according to any one of claims 1-16 or the filter according to claim 17.

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