Resonator and electronic device with a gap structure arranged inside a protrusion structure

Abstract

The present invention relates to a bulk acoustic wave resonator, comprising: a substrate; an acoustic mirror; a bottom electrode, arranged above the substrate; a top electrode, opposite to the bottom electrode and having an electrode connection portion; and a piezoelectric layer, arranged above the bottom electrode and between the bottom electrode and the top electrode, wherein: the edge of the top electrode is provided with a protrusion structure and a gap structure forming a gap located inside the protrusion structure. The present invention also relates to a filter having the bulk acoustic wave resonator, and an electronic device having the filter. Based on the above scheme, the present invention can reduce the generation of clutter in the resonator while suppressing the energy leakage of the resonator.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of semiconductors, and in particular to a bulk acoustic wave resonator, a filter having the resonator, and an electronic device having the filter. Background Art

[0002] Figure 5A FIG. 2 is a top view of a BAW resonator in the prior art. Figure 5B For along Figure 5A A schematic diagram of the cross-sectional structure taken along the A1-A2 line in FIG. Figure 5A and 5B In the figure, the structure corresponding to the reference numerals is as follows:

[0003] 10: Base

[0004] 20: Acoustic mirror, in this example it is a cavity, but Bragg reflection layer or other equivalent sound wave reflection structure can also be used

[0005] 30: Bottom electrode

[0006] 40: Piezoelectric film (piezoelectric layer)

[0007] 50: Top electrode

[0008] 60: Top electrode pin

[0009] AR: Effective acoustic area (acoustic-electric coupling area)

[0010] Figure 5A and Figure 5B The structure not shown in the figure also includes some auxiliary process layers, protective layers, bottom electrode pins, etc.

[0011] In actual working condition, Figure 5A and Figure 5B The AR region of the resonator shown not only produces useful piston mode vibrations, but also produces unfavorable laterally propagating sound waves. These transverse mode sound waves will propagate outside the AR region, causing energy loss and performance degradation in the resonator, which will further degrade the performance of electronic devices using such resonators, such as deteriorating key performance parameters of the filter, such as insertion loss, roll-off, and bandwidth.

[0012] Figure 5C It is a resonator structure for suppressing sound wave leakage in the prior art. Figure 5BThe improvement of the structure is that a protrusion structure is added to the edge of the top electrode 50, which will form an acoustic impedance mismatch area at the edge of the AR region, so that the sound waves propagating laterally outward from the AR region can be reflected back to the AR region, thereby suppressing energy loss. The advantage of this structure is that it has a significant effect on improving the Q value of the resonator, but the disadvantage is that it will increase the clutter in the resonator because the protrusion structure is still in the acoustic-electric coupling region AR, and the electrical performance will be affected while the protrusion structure reflects the sound waves.

[0013] Figure 5D It is another resonator structure for suppressing acoustic wave leakage in the prior art. Figure 5C The improvement is that in addition to adding a protruding structure to the edge of the top electrode 50, the top electrode 50 is further extended outward to form an air wing (cantilever), and the pin 60 also forms an arched structure (hereinafter collectively referred to as the cantilever structure). Since only acoustic vibration exists in the added cantilever structure, the acoustic-electric coupling effect is much smaller than that of the protruding structure, so the clutter generated by the cantilever structure when reflecting sound waves is significantly less than that of the protruding structure. Figure 5D The disadvantage of the structure is that when the sound wave propagates outward from the AR, it will first interact with the protruding structure, forming a reflection and generating considerable clutter. In addition, the sound wave reflected back by the cantilever structure will also interact with the protruding structure to generate some clutter again. Figure 5D The structure in the circuit will still generate more clutter, thus reducing the performance of the resonator. Summary of the invention

[0014] The present invention is proposed to reduce the generation of spurious waves in a resonator while suppressing the energy leakage of the resonator.

[0015] According to one aspect of an embodiment of the present invention, a bulk acoustic wave resonator is provided, comprising:

[0016] substrate;

[0017] Acoustic mirror;

[0018] A bottom electrode disposed above the substrate;

[0019] a top electrode, opposite to the bottom electrode and having an electrode connection portion; and

[0020] a piezoelectric layer disposed above the bottom electrode and between the bottom electrode and the top electrode,

[0021] in:

[0022] The edge of the top electrode is provided with a protrusion structure and a gap structure located inside the protrusion structure to form a gap.

[0023] Optionally, the resonator comprises a cantilever forming the gap structure.

[0024] Optionally, the cantilever includes a single cantilever structure.

[0025] Further optionally, the single cantilever structure has a base layer portion and a cantilever portion, the base layer portion is located at the top electrode; at least a portion of the gap formed by the cantilever portion is located between the base layer portion and the protrusion structure. Optionally, the lateral distance between the protrusion structure and the base layer portion is in the range of 0.5-5μm (optionally 1-3μm), which directly plays an important role in the constructive superposition of the sound waves reflected by the BO and the sound waves reflected by the cantilever, and it is necessary to prevent the distance from being too close to cause mutual interference and the distance from being too far to prevent the sound waves from attenuating and causing insignificant interference; and / or the lateral distance between the outer edge of the protrusion structure and the outer edge of the cantilever portion is in the range of 0-±5μm (optionally 0-±3μm); and / or the longitudinal distance between the top of the protrusion structure and the cantilever portion is in the range of 0-5μm (optionally 0.5-3μm). Or optionally, the cantilever portion has a rising portion connected to the base layer portion, and the rising portion is in a stepped shape. Or optionally, the cantilever portion and the protrusion structure at least partially overlap in the thickness direction of the resonator. Alternatively, the cantilever portion has a rising portion connected to the base layer portion, and the angle formed between the rising portion and the top surface of the top electrode ranges from 15° to 90° (optionally 40° to 70°). Alternatively, another cantilever portion is formed at the end of the top electrode.

[0026] Optionally, the single cantilever structure has a base layer portion and a cantilever portion, the base layer portion is located on the top electrode; the base layer portion is located between the cantilever portion and the protrusion structure. Further optionally, the lateral distance between the protrusion structure and the base layer portion is in the range of 0-5μm (optionally 0.5-3μm); and / or the lateral width of the cantilever portion is in the range of 0.5-5μm (optionally 1-3μm); and / or the lateral distance between the protrusion structure and the cantilever portion is in the range of 1-10μm (optionally 3-5μm).

[0027] Optionally, the single cantilever structure comprises a base layer portion and a cantilever portion, wherein the base layer portion is located on the top of the protruding structure. Further optionally, the cantilever portion and the base layer portion are in the same horizontal plane; or the cantilever portion comprises a rising portion connected to the base layer portion.

[0028] Optionally, the cantilever includes a double cantilever structure, and the double cantilever structure includes a base layer portion and a first single cantilever structure and a second single cantilever structure respectively connected to both sides of the base layer portion. Further optionally, the first single cantilever structure and the second single cantilever structure are arranged asymmetrically. Alternatively, the base layer portion is located on the inner side of the protrusion structure and is arranged on the top electrode. Alternatively, the base layer portion is arranged on the top of the protrusion structure, and further optionally, the base layer portion and the top of the protrusion structure are staggered in the lateral direction.

[0029] Optionally, the resonator includes a bridge portion forming the gap structure. Optionally, the bridge portion is entirely located inside the protrusion structure. Or optionally, the protrusion structure is located in a space formed by the bridge portion.

[0030] Optionally, a recessed structure is located in the gap on the inner side of the protruding structure.

[0031] Optionally, the resonator further comprises a covering layer covering the top electrode, and the base layer portion is a component of the covering layer. The covering layer may only cover a portion of the top electrode.

[0032] Optionally, the gap is filled with air.

[0033] According to another aspect of the embodiments of the present invention, a filter is provided, comprising the above-mentioned BAW resonator.

[0034] According to another aspect of the embodiments of the present invention, an electronic device is provided, comprising the above-mentioned filter or bulk acoustic wave resonator. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The following description and accompanying drawings may better help understand these and other features and advantages of various embodiments disclosed by the present invention, in which the same reference numerals always represent the same components, wherein:

[0036] Figure 1A is a schematic partial cross-sectional view of a thin film bulk acoustic resonator according to an exemplary embodiment of the present invention;

[0037] Figure 1B A schematic diagram exemplarily showing the positional relationship between the protrusion structure and the cantilever structure;

[0038] Figure 1C A schematic partial cross-sectional view of a thin film bulk acoustic resonator exemplarily showing an embodiment of a cantilever structure;

[0039] Figure 1D is a schematic partial cross-sectional view of a thin film bulk acoustic resonator according to an exemplary embodiment of the present invention;

[0040] Figure 2A is a schematic partial cross-sectional view of a thin film bulk acoustic resonator according to an exemplary embodiment of the present invention;

[0041] Figure 2B is a schematic partial cross-sectional view of a thin film bulk acoustic resonator according to an exemplary embodiment of the present invention;

[0042] Figure 2C is a schematic partial cross-sectional view of a thin film bulk acoustic resonator according to an exemplary embodiment of the present invention;

[0043] Figure 2D is a schematic partial cross-sectional view of a thin film bulk acoustic resonator according to an exemplary embodiment of the present invention;

[0044] Figure 2E is a schematic partial cross-sectional view of a thin film bulk acoustic resonator according to an exemplary embodiment of the present invention;

[0045] Figure 3A is a schematic partial cross-sectional view of a thin film bulk acoustic resonator according to an exemplary embodiment of the present invention;

[0046] Figure 3B is a schematic partial cross-sectional view of a thin film bulk acoustic resonator according to an exemplary embodiment of the present invention;

[0047] Figure 3C is a schematic partial cross-sectional view of a thin film bulk acoustic resonator according to an exemplary embodiment of the present invention;

[0048] Figure 3D is a schematic partial cross-sectional view of a thin film bulk acoustic resonator according to an exemplary embodiment of the present invention;

[0049] Figure 4 is a schematic partial cross-sectional view of a thin film bulk acoustic resonator according to an exemplary embodiment of the present invention;

[0050] Figure 5A centered is a top view of a BAW resonator in the prior art;

[0051] Figure 5B For along Figure 5A Schematic diagram of the cross-sectional structure taken along the A1-A2 line;

[0052] Figure 5C It is a resonator structure for suppressing sound wave leakage in the prior art;

[0053] Figure 5D It is another resonator structure for suppressing sound wave leakage in the prior art. DETAILED DESCRIPTION

[0054] The following examples and accompanying drawings further illustrate the technical solution of the present invention. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention, and should not be construed as a limitation of the present invention.

[0055] The following describes a BAW resonator according to an embodiment of the present invention with reference to the drawings. It should be noted that although the FBAW resonator is used as an example in the embodiments of the present invention, the description is applicable to other types of BAW resonators.

[0056] Figure 1A This is an embodiment of the present invention. The figure shows the structure of the edge portion of the top electrode. The improvement is that the cantilever structure is moved to the inside of the protrusion structure. At this time, the material of the cantilever structure can be non-metallic material.

[0057] Specifically, Figure 1A The components and materials are described as follows:

[0058] 50: Top electrode, made of metal material, the material can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or the composite of the above metals or their alloys.

[0059] 51: The protrusion structure may be made of non-metallic materials, such as silicon dioxide, silicon nitride, silicon carbide, aluminum nitride, magnesium oxide, aluminum oxide, or other metal oxides or nitrides or polymers, etc., and may also be made of the same or different metal materials as the top electrode, such as molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite of the above metals or their alloys.

[0060] 80 and 81: Passivation layer: This layer is an optional protective layer that can prevent water vapor, oxygen or other external substances from corroding the resonator (this layer is omitted in subsequent embodiments and is not shown). The protective layer can be made of non-metallic materials such as silicon dioxide, silicon nitride, silicon carbide, aluminum nitride, magnesium oxide, aluminum oxide, or other metal oxides or nitrides or polymers.

[0061] The cantilever structure comprises a base layer 70 and a structural layer 72, wherein:

[0062] 70 : a cantilever base layer, located on the passivation layer 80 or the top electrode 50 , and in contact with the passivation layer 80 or the top electrode 50 .

[0063] 72: Cantilever structure layer, which is divided into an inclined rising portion and a horizontal portion, with an air gap left below the rising portion and the horizontal portion, which can also be filled with other dielectric materials or polymers.

[0064] 70 and 72 may be made of non-metallic materials, such as silicon dioxide, silicon nitride, silicon carbide, aluminum nitride, magnesium oxide, aluminum oxide, or other metal oxides or nitrides or polymers, etc., and may also be made of metal materials such as molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite or alloy of the above metals.

[0065] The overall thickness range of the cantilever structure layer can be (Optional )

[0066] In addition, the piezoelectric layer of the bulk wave resonator in the present invention can be made of materials such as aluminum nitride and zinc oxide, and the materials can be doped with rare earth elements, and the piezoelectric layer and the electrode layer both have a thin film structure.

[0067] Figure 1A The structure in can produce at least one of the following technical effects:

[0068] 1) The combination of the cantilever and the protrusion structure can significantly improve the sound wave reflection performance, thereby improving the Q value of the resonator.

[0069] 2) The cantilever structure is located on the inner side of the protrusion structure. In this way, when the sound wave propagates outward from the AR, it will first be reflected by the cantilever structure, thereby reducing the sound wave energy transmitted to the protrusion structure, thereby reducing the generation of parasitic mode clutter.

[0070] 3) The cantilever structure in the traditional structure is usually an extension of the top electrode, and the material is generally metal. When the cantilever structure is close to the piezoelectric layer in the longitudinal direction, a certain acoustic-electric coupling phenomenon will still occur, which limits the size design of the cantilever structure. The cantilever structure in this embodiment can be made of non-metallic materials, so the acoustic-electric coupling phenomenon can be avoided, thereby giving greater freedom to size design.

[0071] 4) In this structure, the protrusion structure can be located in the gap between the cantilever structure and the piezoelectric layer, thereby changing the shape of the gap formed by the cantilever structure. The protrusion structure and the cantilever structure can form a certain matching relationship to adjust the sound wave reflection performance of the cantilever structure, which does not exist in the traditional structure.

[0072] The above description of the technical effects is also applicable when similar structures exist in other embodiments of the present invention.

[0073] for Figure 1A The size of the cantilever structure and its positional relationship with the protrusion structure are Figure 1BThe constraint relationship between them (the passivation layer 80 has been omitted). Where D1 is the distance from the edge of the cantilever structure to the outer edge of the protruding structure, and its range is +5--5μm, and it can be selected from +3--3μm, such as 2μm. A positive value indicates that the edge of the cantilever structure is on the right side of the outer edge of the protruding structure, and a negative value indicates that it is on the left side; D2 represents the distance between the starting point of the rising part of the cantilever structure and the inner edge of the protruding structure, and its range is 0.5-5μm, and it can be selected from 1-3μm; H1 represents the distance between the lower surface of the horizontal part of the cantilever structure and the upper surface of the protruding structure, and its range is 0-5μm, and it can be selected from 0.5-3μm, such as 2μm; θ represents the acute angle formed by the rising part of the cantilever structure and the horizontal direction, and its range is 15°-90°, and it can be selected from 40°-70°, such as 50°. The above parameters can be adjusted or selected at the same time, or only one, two or three of the above parameters can be adjusted.

[0074] Based on certain process conditions, the shape of the rising portion of the cantilever part of the structure proposed by the present invention can also be Figure 1C In addition, the base layer portion 70 of the cantilever structure may also only cover part of the top electrode. Optionally, the resonator further includes a covering layer covering the top electrode; the base layer portion is a component of the covering layer. The covering layer here may be a passivation layer or other metal material layer. The covering layer may only cover a part of the top electrode.

[0075] In addition, in order to simplify the process and enhance the structural stability of the cantilever structure, the Figure 1A The air gap between the mid-hanging wing structure and the protruding structure forms Figure 1D The cantilever-protrusion fitting structure in the embodiment. At this time, the H1 mentioned above is zero.

[0076] In addition, the extension direction of the cantilever structure can be changed from extending toward the protrusion structure side to extending toward the inner side, thereby forming a Figure 2A Structural changes in. There is a gap D5 between the edge of the base structure layer of the cantilever structure and the inner edge of the protruding structure, which ranges from 0-5μm, and can be selected from 0.5-3μm, such as 2μm; the distance between the starting point of the rising part of the cantilever structure and the inner edge of the protruding structure is D6, which ranges from 1-10μm, and can be selected from 3-5μm, such as 2μm; the width D7 of the structural layer of the cantilever structure ranges from 0.5-5μm, and can be selected from 1-3μm, such as 2μm; the angle between the rising part of the cantilever structure and the horizontal direction and the distance between the lower surface of the horizontal part of the structural layer of the cantilever structure and the upper surface of the protruding structure can be referred to Figure 1B Instance of size range in .

[0077] In the present invention, the distance between two components refers to the shortest straight line (longitudinal or transverse) distance between the two.

[0078] Also available in Figure 2AAdd a descending part to the right side of the cantilever structure to form Figure 2B The cantilever-protrusion structure in the cantilever structure. The distance between the starting point of the rising part and the end point of the descending part of the cantilever structure is D8, ranging from 0.5-5μm, and optionally 1-3μm. In addition, the distance between the lower surface of the horizontal part of the cantilever structure and the protrusion structure, and the angle between the rising part and the descending part and the horizontal direction can be referred to Figure 1B The H1 and θ of the rising part, the distance from the starting point of the rising part to the inner edge of the protruding structure, and the distance from the edge of the base layer of the cantilever structure to the inner edge of the protruding structure can be referred to Figure 2A D6 and D5.

[0079] If you will Figure 2B The starting point of the rising part of the middle suspension wing structure and the base layer of the left suspension wing structure are moved to the outside of the protruding structure, so that Figure 2C The distance between the starting point of the left rising part and the outer edge of the protruding structure is D10, ranging from 0.5-5μm, and can be 1-3μm, such as 2μm; the distance between the end point of the right descending part and the inner edge of the protruding structure is D9, ranging from 0.5-5μm, and can be 1-3μm, such as 2μm. In addition, the angle between the rising part and the descending part and the horizontal direction can be referred to Figure 1B The distance between the lower surface of the horizontal part of the cantilever structure and the upper surface of the protrusion structure can be referred to as Figure 1B H1.

[0080] You can also Figure 2A The cantilever structure in the middle moves to the upper surface of the protruding structure to form Figure 2D The horizontal distance between the lower surface of the horizontal part of the cantilever structure and the upper surface of the protruding structure is H3, ranging from 0-5 μm, and optionally 0.5-2 μm; the width of the cantilever structure is D11, ranging from 0.5-5 μm, and optionally 1-3 μm.

[0081] Based on specific process conditions, it can also be omitted Figure 2D The rising part of the cantilever structure becomes Figure 2E The straight style in .

[0082] In addition, you can Figure 1A and Figure 2A The cantilever structure is combined to form Figure 3A The double cantilever-protrusion structure in the left cantilever structure 72 can be referred to as Figure 1B The base layer width of the cantilever structure is D3, ranging from 1 to 10 μm, and can be 3 to 5 μm, such as 2 μm, and the right cantilever structure 73 and the left cantilever structure 72 are kept symmetrical. By adopting a double cantilever structure, the ability to reflect sound waves can be further enhanced.

[0083] Since there is a protruding structure under the left cantilever structure 72, but there is no protruding structure under the right cantilever structure 73, the two cantilever structures have an asymmetric effect on the sound wave reflection. In order to optimize the reflection effect, an asymmetric double cantilever structure can be used, for example Figure 3B The horizontal parts of the cantilever structures on both sides are shown to be of unequal length. The length of the horizontal part of the right cantilever structure is D4, and the difference between this length and the horizontal part of the left cantilever structure is in the range of +5--5μm, and can be +3--3μm, such as 2μm, where a positive value means that the right side is longer than the left side, and a negative value means that it is shorter than the left side.

[0084] In addition to the asymmetric strategy of using the double-hanging wing structure with unequal horizontal lengths, Figure 3C Asymmetric arrangement with unequal heights in the middle horizontal part. There is a height difference H2 between the two cantilever structures 73 and 72 (based on the lower surface), ranging from +5 to 5μm, optionally +3 to 3μm, such as 2μm, a positive value means that the right cantilever structure 73 is higher than the left cantilever structure 72, and a negative value means the opposite.

[0085] In addition, the base layer 70 of the double-wing cantilever structure can also be moved to the upper surface of the protruding structure 51, thereby forming Figure 3D The right cantilever structure 73 and the left cantilever structure 72 can be adopted Figure 3A The symmetrical size relationship can also be used Figure 3B and 3C In addition, the two endpoints of the base layer 70 of the cantilever structure are not necessarily aligned with the two side edges of the protrusion structure, and can be kept at distances D12 and D13 therefrom respectively, with the range of D12 being +0.5-+3μm or -0.5-3μm, optionally +1-+2μm or optionally -1--2μm, such as 1μm, where a positive value indicates that the base layer endpoint is outside the upper surface of the protrusion, and a negative value indicates that it is inside the upper surface of the protrusion, the range of D13 refers to D12, and the meanings of positive and negative values ​​are the same as those of D12.

[0086] In addition, the positional characteristics of the cantilever structure in the present invention can be combined with the traditional cantilever-protrusion to obtain Figure 4 The embodiment shown in the figure, wherein the structures corresponding to reference numerals 51 and 52 constitute a conventional cantilever-protrusion structure; reference numeral 53 is an optional recessed structure.

[0087] Based on the above, the present invention proposes a bulk acoustic wave resonator, comprising:

[0088] substrate;

[0089] Acoustic mirror;

[0090] A bottom electrode disposed above the substrate;

[0091] a top electrode, opposite to the bottom electrode and having an electrode connection portion; and

[0092] a piezoelectric layer disposed above the bottom electrode and between the bottom electrode and the top electrode,

[0093] in:

[0094] The edge of the top electrode is provided with a protrusion structure and a gap structure located inside the protrusion structure to form a gap.

[0095] As mentioned above, the gap may be an air gap, or a filled gap filled with a dielectric material or a polymer or the like.

[0096] In the present invention, when the sound wave propagates laterally outward from the AR, the inner side of the component reflects the sound wave first, and the outer side of the component reflects the sound wave later. In other words, the inner side and the outer side are determined by the order in the direction of sound wave propagation.

[0097] The gap structure may be formed by a cantilever (single cantilever or double cantilever) or a bridge structure. In the case of a double cantilever, the two cantilever may be arranged asymmetrically.

[0098] Based on the above, the present invention further proposes a filter, comprising a plurality of the above-mentioned BAW resonators. The present invention further proposes an electronic device, comprising the above-mentioned filter or the above-mentioned BAW resonator.

[0099] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A bulk acoustic wave resonator, include: substrate; Acoustic mirror; A bottom electrode disposed above the substrate; A top electrode, opposite to the bottom electrode and having an electrode connecting portion; and a piezoelectric layer disposed above the bottom electrode and between the bottom electrode and the top electrode, in: The edge of the top electrode is provided with a protrusion structure and a gap structure located inside the protrusion structure to form a gap; The protrusion structures are all located in the gap structure.

2. The resonator according to claim 1, in: The resonator includes a cantilever forming the air gap structure.

3. The resonator according to claim 2, in: The cantilever wing comprises a single cantilever wing structure.

4. The resonator according to claim 3, in: The single cantilever wing structure comprises a base layer portion and a cantilever wing portion, wherein the base layer portion is located at the top electrode; At least a portion of the gap formed by the cantilever portion is located between the base layer portion and the protrusion structure.

5. The resonator according to claim 4, in: The lateral distance (D2) between the protrusion structure and the base layer portion is in the range of 0.5-5μm; and / or the lateral distance (D1) between the outer edge of the protrusion structure and the outer edge of the cantilever portion is in the range of 0-±5μm; and / or the longitudinal distance (H1) between the top of the protrusion structure and the cantilever portion is in the range of 0-5μm.

6. The resonator according to claim 5, in: The lateral distance (D2) between the protrusion structure and the base layer portion is in the range of 1-3μm; and / or the lateral distance (D1) between the outer edge of the protrusion structure and the outer edge of the cantilever portion is in the range of 0-±3μm; and / or the longitudinal distance (H1) between the top of the protrusion structure and the cantilever portion is in the range of 0.5-3μm.

7. The resonator according to claim 4, in: The cantilever portion has a rising portion connected to the base layer portion, and the rising portion is in a step shape.

8. The resonator according to claim 4, in: The cantilever portion and the protrusion structure at least partially overlap in the thickness direction of the resonator.

9. The resonator according to claim 4, in: The cantilever portion has a rising portion connected to the base layer portion, and an angle formed between the rising portion and a top surface of the top electrode is in a range of 15-90 degrees.

10. The resonator according to claim 9, in: The angle formed between the rising portion and the top surface of the top electrode is in the range of 40-70°.

11. The resonator according to claim 4, in: The cantilever wing portion is a first cantilever wing portion; A second cantilever portion is formed at an end of the top electrode.

12. The resonator according to claim 2, in: The cantilever wing comprises a double cantilever wing structure, and the double cantilever wing structure comprises a base layer portion and a first single cantilever wing structure and a second single cantilever wing structure respectively connected to two sides of the base layer portion.

13. The resonator according to claim 12, in: The first single-cantilever wing structure and the second single-cantilever wing structure are arranged asymmetrically.

14. The resonator according to claim 12, in: The base layer portion is located inside the protrusion structure and is disposed on the top electrode.

15. The resonator according to claim 1, in: The resonator includes a bridge portion forming the air-gap structure.

16. The resonator according to claim 15, in: The protrusion structure is located in a space formed by the bridge portion.

17. The resonator according to claim 1, in: A recessed structure is located in the gap on the inner side of the protruding structure.

18. The resonator according to claim 4, in: The resonator further includes a cover layer covering the top electrode; The base layer portion is a component of the cover layer.

19. The resonator according to claim 12, in: The resonator further includes a cover layer covering the top electrode; The base layer portion is a component of the cover layer.

20. The resonator according to claim 18, in: The capping layer covers only a portion of the top electrode.

21. The resonator according to claim 19, in: The capping layer covers only a portion of the top electrode.

22. The resonator according to any one of claims 1 to 21, in: The gap is filled with air.

23. A filter comprising the BAW resonator according to any one of claims 1 to 22.

24. An electronic device comprising the filter according to claim 23 or the BAW resonator according to any one of claims 1 to 22.

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