Bulk acoustic wave resonator, filter and electronic device with central defect structure

Abstract

The present invention relates to a bulk acoustic wave resonator, comprising: a substrate; an acoustic mirror; a bottom electrode; a top electrode; a piezoelectric layer, wherein: the area where the acoustic mirror, the bottom electrode, the piezoelectric layer, and the top electrode overlap in the thickness direction of the substrate is the effective area of ​​the resonator; and the effective area is formed with a central defect structure, and in the top view of the resonator, at least a part of the central defect structure is located in the high temperature area of ​​the effective area, the high temperature area refers to an area with the center of mass of the effective area as the center of the circle and r as the radius, the radius r is 50% of the radius of the equivalent circle of the effective area where the high temperature area is located, and the equivalent circle is: a circle with the center of mass of the effective area as the center of the circle and the area of ​​the circle equal to the area of ​​the effective area. The present invention also relates to filters and electronic devices.

Description

Technical Field

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

[0002] Film Bulk Acoustic Resonator (FBAR, also known as BAW) plays an important role in the communication field as a MEMS chip. FBAR filter has excellent characteristics such as small size (μm level), high resonance frequency (GHz), high quality factor (1000), large power capacity, and good roll-off effect. It is gradually replacing traditional surface acoustic wave (SAW) filters and ceramic filters, and plays a huge role in the field of wireless communication radio frequency. Its high sensitivity advantage can also be applied to biological, physical, medical and other sensing fields.

[0003] The main structure of the film bulk acoustic wave resonator is a "sandwich" structure consisting of electrode-piezoelectric film-electrode, that is, a layer of piezoelectric film material is sandwiched between two layers of metal electrode layers. By inputting a sinusoidal signal between the two electrodes, the FBAR uses the inverse piezoelectric effect to convert the input electrical signal into mechanical resonance, and then uses the piezoelectric effect to convert the mechanical resonance into an electrical signal output. The film bulk acoustic wave resonator mainly uses the longitudinal piezoelectric coefficient (d33) of the piezoelectric film to produce the piezoelectric effect, so its main working mode is the longitudinal wave mode in the thickness direction (Thickness Extensional Mode, referred to as TE mode).

[0004] Fig. 10A is a top view of a BAW resonator in the prior art, Fig. 10B for Fig. 10A A cross-sectional view along the broken line A1OA2. Figures 10A-10B As shown, by removing the piezoelectric layer 50 above the fold line B10′B2, a portion of the bottom electrode 40, the bottom electrode pin 35 and the substrate 10 can be exposed in the top view, and the details of each portion are described as follows:

[0005] 10: Substrate, usually the materials can be single crystal silicon, gallium arsenide, sapphire, quartz, etc.

[0006] 20: Acoustic mirror, which is an air cavity in the above example, but a Bragg reflection layer or other equivalent acoustic reflection structures may also be used.

[0007] 40(35) / 60(65): Bottom electrode (pin) / top electrode (pin), which can be made of molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite or alloy of the above metals.

[0008] 50: Piezoelectric layer film, which can be made of aluminum nitride, zinc oxide, PZT and other materials and contains rare earth element doping materials with a certain atomic ratio of the above materials.

[0009] Fig. 10C Shows Fig. 10A Schematic diagram of the temperature gradient distribution of the effective area AR of the corresponding resonator (wherein the dark area represents low temperature and the bright area represents high temperature), and the highest temperature point is located at Σ in the figure.

[0010] When the above resonator is working, part of the acoustic vibration energy and electrical energy will inevitably be converted into heat energy. As the power of the resonator increases, the heating problem becomes increasingly significant, resulting in the resonator operating temperature being too high. High temperature not only has an adverse effect on the frequency characteristics of the resonator, but also accelerates the aging and damage of various components of the device. The heating problem is particularly obvious in the central area of ​​the resonator's effective area. Summary of the invention

[0011] The present invention proposes a defective power enhancement structure placed at or near the center of the top view of the effective acoustic area of ​​a bulk wave resonator, which can make the vibration frequency of the highest temperature point in the resonator and its vicinity deviate from the resonance point, thereby achieving the purpose of reducing the resonator temperature.

[0012] According to one aspect of an embodiment of the present invention, a bulk acoustic wave resonator is provided, comprising:

[0013] substrate;

[0014] Acoustic mirror;

[0015] bottom electrode;

[0016] Top electrode;

[0017] Piezoelectric layer,

[0018] in:

[0019] The area where the acoustic mirror, the bottom electrode, the piezoelectric layer, and the top electrode overlap in the thickness direction of the substrate is the effective area of ​​the resonator; and

[0020] The effective area is formed with a central defect structure. In the top view of the resonator, at least a portion of the central defect structure is located in the high temperature area of ​​the effective area. The high temperature area refers to an area with the center of mass of the effective area as the center and r as the radius. The radius r is 50% of the radius of the equivalent circle of the effective area where the high temperature area is located, and optionally 20%. The equivalent circle is a circle with the center of mass of the effective area as the center and an area equal to the area of ​​the effective area.

[0021] Optionally, the central defect structure includes an arched structure or a recessed structure formed by the top electrode or the bottom electrode itself. Optionally, the arched structure forms a gap between the top electrode or the bottom electrode and the piezoelectric layer, and the recessed structure forms a concave shape on a side of the top electrode or the bottom electrode away from the piezoelectric layer. Optionally, the thickness of the portion of the top electrode or the bottom electrode forming the arched structure or the recessed structure is the same as the thickness of the other portions.

[0022] Optionally, the thickness of the gap or the depth of the concave shape is within the range.

[0023] Optionally, the gap or the concave shape is filled with air or a dielectric material or a metal oxide.

[0024] Optionally, the gap or the concave shape is filled with a metal having a density greater than that of the electrode material.

[0025] Optionally, the central defect structure is an electrode filling structure disposed in the top electrode or the bottom electrode, and the density of the metal constituting the electrode filling structure is greater than the density of the corresponding electrode material. Optionally, the electrode filling structure is disposed in a through hole of the corresponding electrode, and the electrode filling structure is flush with the electrode where it is located.

[0026] Optionally, the central defect structure is a metal protrusion disposed on the top electrode or the bottom electrode, and the metal protrusion protrudes from one side of the corresponding electrode.

[0027] Optionally, the central defect structure is a piezoelectric layer filling structure disposed in the piezoelectric layer. Optionally, the piezoelectric layer filling structure extends at least partially in the thickness direction of the piezoelectric layer. Optionally, the piezoelectric layer filling structure is disposed in a through hole in the piezoelectric layer and is connected to the top electrode and the bottom electrode.

[0028] Optionally, the material of the piezoelectric layer filling structure is selected from air or a non-piezoelectric non-conductive material. Optionally, the non-piezoelectric non-conductive material includes silicon dioxide, silicon nitride, silicon carbide, aluminum oxide or magnesium oxide.

[0029] Optionally, the resonator further comprises an auxiliary layer disposed on the top electrode; the central defect structure comprises an arched structure, a recessed structure, a convex structure formed by the auxiliary layer itself, or a filling structure disposed in the auxiliary layer.

[0030] Optionally, in the top view of the resonator, the shape of the central defect structure is circular, square or polygonal similar to the shape of the effective area. Optionally, in the top view of the resonator, the maximum size of the central defect structure is in the range of 1-50 μm; or within 20% of the length of the longest side of the effective area of ​​the polygonal resonator. Optionally, in the top view of the resonator, the maximum size of the central defect structure is in the range of 1-10 μm; or within 5% of the length of the longest side of the effective area of ​​the polygonal resonator.

[0031] An embodiment of the present invention further provides a bulk acoustic wave resonator, comprising:

[0032] substrate;

[0033] Acoustic mirror;

[0034] bottom electrode;

[0035] Top electrode;

[0036] Piezoelectric layer,

[0037] in:

[0038] The area where the acoustic mirror, the bottom electrode, the piezoelectric layer, and the top electrode overlap in the thickness direction of the substrate is the effective area of ​​the resonator; and

[0039] A central defect structure is formed in the effective area. In the top view of the resonator, the central defect structure is located in at least a part of the high-temperature area. The thickness and / or material of the central defect structure is different from the layer where the central defect structure is located. The high-temperature area refers to an area with the center of mass of the effective area as the center and r as the radius. The radius r is 50% of the radius of the equivalent circle of the effective area where the high-temperature area is located, and optionally 20%. The equivalent circle is: a circle with the center of mass of the effective area as the center and an area equal to the area of ​​the effective area.

[0040] Optionally, in the present invention, the central defect area is arranged in the high temperature area.

[0041] According to yet another aspect of the embodiments of the present invention, a filter is provided, comprising the above-mentioned resonator.

[0042] According to another aspect of the embodiments of the present invention, an electronic device is provided, comprising the above-mentioned resonator or the above-mentioned filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] 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:

[0044] Figure 1A is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

[0045] Figure 1B According to an exemplary embodiment of the present invention Figure 1A Schematic diagram of the central defect structure in;

[0046] Figure 1C According to another exemplary embodiment of the present invention Figure 1A Schematic diagram of the central defect structure in;

[0047] Figure 1D According to another exemplary embodiment of the present invention Figure 1A Schematic diagram of the central defect structure and the shape of the effective area;

[0048] Figure 1E According to an exemplary embodiment of the present invention Figure 1A Schematic diagram of the size of the central defect structure in;

[0049] Figure 2 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

[0050] Figure 3 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

[0051] Figure 4 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

[0052] Figure 5 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

[0053] Figure 6 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

[0054] Figure 7 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

[0055] Figure 8 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

[0056] Fig. 9 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

[0057] Fig. 10A is a top view of a bulk acoustic wave resonator in the prior art;

[0058] Fig. 10B for Fig. 10A A cross-sectional view along the fold line A1OA2;

[0059] Fig. 10C for Fig. 10A Schematic diagram of the temperature gradient distribution of the corresponding effective area AR of the resonator, where the dark area represents low temperature and the bright area represents high temperature, and the highest temperature point is located at Σ in the figure. DETAILED DESCRIPTION

[0060] The technical solution of the present invention is further specifically described below by examples and in conjunction with the accompanying drawings. In the specification, the same or similar reference numerals indicate 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 overall inventive concept of the present invention and should not be construed as a limitation of the present invention.

[0061] Figure 1A FIG. 1 is a schematic cross-sectional view of a bulk acoustic wave resonator A100 according to an exemplary embodiment of the present invention.

[0062] The details of each part are as follows:

[0063] 10: Substrate, usually the materials can be single crystal silicon, gallium arsenide, sapphire, quartz, etc.

[0064] 20: Acoustic mirror, which is an air cavity in the above example, but a Bragg reflection layer or other equivalent acoustic reflection structures may also be used.

[0065] 40(35) / 60(65): Bottom electrode (pin) / top electrode (pin), which can be made of molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite or alloy of the above metals.

[0066] 50: Piezoelectric layer film, which can be made of aluminum nitride, zinc oxide, PZT and other materials and contains rare earth element doping materials with a certain atomic ratio of the above materials.

[0067] There is an arched structure 70 near the center of the top electrode of the resonator shown in Example A100, so that the arched structure 70 is separated from the piezoelectric layer 50 therebelow and a gap 71 is formed, wherein the gap 71 can be an air gap, or can be filled with dielectric materials such as silicon dioxide, silicon nitride, silicon carbide, various metal oxides such as aluminum oxide, magnesium oxide, etc., or heavy metal materials such as gold, platinum, iridium, osmium, tungsten, etc., and the density of the heavy metal filled in the gap 71 can be greater than the metal density of the surrounding electrode material.

[0068] When filled with non-metallic substances (including air), the excitation electric field of the aluminum nitride under the arched structure will become weaker, so the vibration of the piezoelectric layer will weaken, and the thermal power of the central area with the highest temperature will also decrease, thereby reducing the center temperature of the resonator.

[0069] When filling with heavy metal, the electric field under the arch structure 70 will not be weakened or eliminated, but because the density of the filling metal is greater than that of the surrounding electrode material, the filling metal will form a more significant mass load on the electrode arch structure 70 and the effective acoustic area covered by the heavy metal filled thereunder. This load will reduce the amplitude of the local area where the arch structure 70 / gap 71 is located and make the frequency of this area deviate from the resonance point of the surrounding acoustic area, thereby also reducing the center temperature of the resonator.

[0070] Figure 1B According to an exemplary embodiment of the present invention Figure 1A Schematic diagram of the central defect structure in . Figure 1C According to another exemplary embodiment of the present invention Figure 1A Schematic diagram of the central defect structure in .

[0071] The central defect structure can be made into a circle as shown in 1B, wherein the diameter D1 of the circle ranges from 1 to 50 μm, preferably from 1 to 10 μm. The defect structure can also be made into Figure 1C The side length a1 of the square shown is in the range of 1-50 μm, preferably in the range of 1-10 μm.

[0072] Figure 1D According to another exemplary embodiment of the present invention Figure 1A Schematic diagram of the central defect structure and the shape of the effective area in FIG. The top view shape of the central defect structure can also be a reduced similar shape of the effective acoustic area of ​​the resonator where it is located. Figure 1D As shown, the effective acoustic area AR of the resonator is an irregular polygon, and its defect structure C1 is a similar shape of the polygon. Its reduction ratio should ensure that the longest side of C1 falls within the length range of 1-50μm. The various top-view shapes and size ranges described above are applicable to all subsequent defect structure embodiments. In the present invention, the maximum size of the central defect structure is Figure 1D where is the length of the longest side of the polygon, Figure 1C where is the side length of the square, Figure 1B The diameter of the center circle.

[0073] Figure 1E According to an exemplary embodiment of the present invention Figure 1A Schematic diagram of the size of the central defect structure in FIG. The air gap / filling portion 71 has the following Figure 1E The thickness shown is h1, which ranges from

[0074] In the present invention, in the top view of the resonator, the maximum size of the central defect structure is in the range of 1-50 μm, or within 20% of the length of the longest side of the effective area of ​​the polygonal resonator; further, in the top view of the resonator, the maximum size of the central defect structure is in the range of 1-10 μm, or within 5% of the length of the longest side of the effective area of ​​the polygonal resonator.

[0075] In the present invention, the value of a numerical range may be, in addition to being an endpoint value (including the endpoint value) or a value adjacent to the endpoint value within the range (excluding the endpoint value), a median value of the range, etc.

[0076] Figure 2 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment A200 of the present invention.

[0077] The details of each part are as follows:

[0078] 10: Substrate, usually the materials can be single crystal silicon, gallium arsenide, sapphire, quartz, etc.

[0079] 20: Acoustic mirror, which is an air cavity in the above example, but a Bragg reflection layer or other equivalent acoustic reflection structures may also be used.

[0080] 40(35) / 60(65): Bottom electrode (pin) / top electrode (pin), which can be made of molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite or alloy of the above metals.

[0081] 50: Piezoelectric layer film, which can be made of aluminum nitride, zinc oxide, PZT and other materials and contains rare earth element doping materials with a certain atomic ratio of the above materials.

[0082] A heavy metal filling part 70 is embedded in the central area of ​​the top electrode 60 of the embodiment A200. The material of the heavy metal filling part 70 is the same as that of the heavy metal filling part in the embodiment A100. The top electrode 60 and the metal filling part 70 form a flat area. The advantage of this structure is that the impedance mismatch effect caused by the central defect can be further reduced compared with the embodiment A100.

[0083] Figure 6 The bottom electrode also has Figure 2 The same setting as the top electrode in is omitted here.

[0084] Figure 3 is a schematic cross-sectional view of a bulk acoustic wave resonator A300 according to an exemplary embodiment of the present invention.

[0085] The details of each part are as follows:

[0086] 10: Substrate, usually the materials can be single crystal silicon, gallium arsenide, sapphire, quartz, etc.

[0087] 20: Acoustic mirror, which is an air cavity in the above example, but a Bragg reflection layer or other equivalent acoustic reflection structures may also be used.

[0088] 40(35) / 60(65): Bottom electrode (pin) / top electrode (pin), which can be made of molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite or alloy of the above metals.

[0089] 50: Piezoelectric layer film, which can be made of aluminum nitride, zinc oxide, PZT and other materials and contains rare earth element doping materials with a certain atomic ratio of the above materials.

[0090] In the embodiment A300, the heavy metal loading part 70 is located near the center of the upper surface of the upper electrode. This structure can be manufactured by metal deposition and etching processes after the upper electrode is machined and formed, thus significantly simplifying the process. The material of the heavy metal loading part 70 is the same as that of the heavy metal filling part in the embodiment A100. Figure 3 In the figure, the heavy metal load portion corresponds to the protrusion.

[0091] Although in Figure 3 Only the protrusion protruding upward from the upper side of the top electrode is shown in the figure, but the present invention is not limited thereto. For example, the protrusion may protrude from the lower side of the top electrode toward the piezoelectric layer. The bottom electrode may also be provided with a protrusion structure of the same type. Figure 7 As shown, the bottom electrode also has Figure 3 The same setting as the bottom electrode in is omitted here.

[0092] Figure 4 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention.

[0093] The details of each part are as follows:

[0094] 10: Substrate, usually the materials can be single crystal silicon, gallium arsenide, sapphire, quartz, etc.

[0095] 20: Acoustic mirror, which is an air cavity in the above example, but a Bragg reflection layer or other equivalent acoustic reflection structures may also be used.

[0096] 40(35) / 60(65): Bottom electrode (pin) / top electrode (pin), which can be made of molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite or alloy of the above metals.

[0097] 50: Piezoelectric layer film, which can be made of aluminum nitride, zinc oxide, PZT and other materials and contains rare earth element doping materials with a certain atomic ratio of the above materials.

[0098] In the embodiment A400, no heavy metal structure is used, but a defect structure is embedded in the upper surface of the piezoelectric layer 50, and then the upper electrode is directly deposited on the upper surface of the piezoelectric layer. The manufacturing process of this structure is simpler than that of A300, and it also avoids the use of expensive heavy metals, thereby significantly reducing costs.

[0099] Figure 5 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention.

[0100] The details of each part are as follows:

[0101] 10: Substrate, usually the materials can be single crystal silicon, gallium arsenide, sapphire, quartz, etc.

[0102] 20: Acoustic mirror, which is an air cavity in the above example, but a Bragg reflection layer or other equivalent acoustic reflection structures may also be used.

[0103] 40(35) / 60(65): Bottom electrode (pin) / top electrode (pin), which can be made of molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite or alloy of the above metals.

[0104] 50: Piezoelectric layer film, which can be made of aluminum nitride, zinc oxide, PZT and other materials and contains rare earth element doping materials with a certain atomic ratio of the above materials.

[0105] In the embodiment A500, a through hole 70 is formed in the center of the piezoelectric layer. The through hole 70 may be filled with air or other non-piezoelectric non-conductive materials, such as silicon dioxide, silicon nitride, silicon carbide, aluminum oxide, magnesium oxide, etc. Since the piezoelectric material is removed from the central area of ​​the embodiment A500, the heat generation in the area 70 can be completely eliminated.

[0106] It should be pointed out that the central defect structure in the above embodiments A100-400 is not limited to the top electrode, but can also be symmetrically manufactured at the corresponding position of the bottom electrode, so that the above defect structure is present on the top electrode and / or bottom electrode of the derived structure.

[0107] It should be pointed out that in the present invention, "high temperature area" refers to an area with the center of mass of the effective area as the center of the circle and r as the radius, and the radius r is 50% of the radius of the equivalent circle of the effective area, and further 20%. The above-mentioned equivalent circle is: a circle with the center of mass of the effective area as the center of the circle and the area of ​​the circle equal to the area of ​​the effective area. Generally speaking, the energy exchange efficiency of the electric field and the acoustic field in the center of mass area of ​​the resonator is the largest, so the heat generation power is also the largest; at the same time, when the effective area of ​​the resonator is a convex geometric figure, the center of mass area is surrounded by the surrounding material more evenly than other areas, resulting in the lowest heat dissipation efficiency in this area. Therefore, the center of mass of the effective area is used as the heating center of the resonator with a convex geometric effective area.

[0108] In the present invention, only a portion of the upper end of the support structure may be located in the high temperature area, or the entire upper end of the support structure may be located in the high temperature area, which is within the protection scope of the present invention.

[0109] Since the working process of the resonator is essentially the interaction between the piezoelectric material and the field, the spatial distribution of the thermal power density of the resonator is directly related to the spatial distribution of the material in the effective area of ​​the resonator, and for the resonator with a convex geometry in the effective area, the position with the highest thermal power density is located near the center (center of mass) of the material distribution. Although the effective area of ​​the resonator is composed of different materials such as the metal electrode layer and the piezoelectric layer in the thickness direction, since the thickness of each material layer is usually uniform (or approximately uniform), the equivalent surface density of the effective area can be considered to be uniform in the top view plane. In the above case, the position of the planar center of mass of the effective area is the planar geometric center of the area.

[0110] In the present invention, on the one hand, the metal electrode is retained in the high-temperature area, which can improve the thermal conductivity from the high-temperature area to the non-high-temperature area, thereby improving the heat dissipation performance of the resonator; on the other hand, since metal or other fillers are used to maintain the continuity of the electrode and the process layers such as the piezoelectric layer and the passivation layer, compared with the method of constructing through holes on the electrode, the structure of the present invention can reduce the formation of the acoustic impedance mismatch area in the center of the resonator, thereby avoiding the generation of parasitic modes to a large extent and preventing the important electrical parameters of the resonator (such as Q value and electromechanical coupling coefficient, etc.) from being greatly deteriorated.

[0111] In the present invention, in addition to being arranged at the top electrode, the piezoelectric layer, and the bottom electrode, the central defect region may also be arranged at other locations, such as being arranged at the passivation layer. Figure 8-9 An alternative embodiment is shown.

[0112] exist Figure 8 In the figure, 80 is a passivation layer or other process layer (ie, an auxiliary layer), and 81 is a protrusion made of the same material as or different from the passivation layer, which functions to change the vibration frequency of the central area of ​​the resonator by increasing the mass load.

[0113] exist Fig. 9 In the figure, 80 is a passivation layer or other process layer (i.e., an auxiliary layer), and 81 is an arched structure with the passivation layer itself, which functions to locally separate the passivation layer from the effective acoustic area to reduce the mass load of the separation area, thereby changing the local resonant frequency.

[0114] exist Figure 8 The central defect structure formed by the auxiliary layer is a protrusion. Fig. 9 In the figure, the central defect structure formed by the auxiliary layer is a convex structure, but although not shown, the central defect structure formed by the auxiliary layer can also be a concave structure or a filling structure arranged in the auxiliary layer. The filling structure here can be similar to the filling method in the bottom electrode, the top electrode or the piezoelectric layer, which will not be repeated here.

[0115] Based on the above, the present invention proposes the following technical solutions:

[0116] 1. A bulk acoustic wave resonator, comprising:

[0117] substrate;

[0118] Acoustic mirror;

[0119] bottom electrode;

[0120] Top electrode;

[0121] Piezoelectric layer,

[0122] in:

[0123] The area where the acoustic mirror, the bottom electrode, the piezoelectric layer, and the top electrode overlap in the thickness direction of the substrate is the effective area of ​​the resonator; and

[0124] The effective area forms a central defect structure. In the top view of the resonator, at least a portion of the central defect structure is located in the high-temperature area of ​​the effective area. The high-temperature area refers to an area with the center of mass of the effective area as the center and r as the radius. The radius r is 50% of the radius of the equivalent circle of the effective area where the high-temperature area is located. The equivalent circle is a circle with the center of mass of the effective area as the center and an area equal to the area of ​​the effective area.

[0125] 2. A bulk acoustic wave resonator, comprising:

[0126] substrate;

[0127] Acoustic mirror;

[0128] bottom electrode;

[0129] Top electrode;

[0130] Piezoelectric layer,

[0131] in:

[0132] The area where the acoustic mirror, the bottom electrode, the piezoelectric layer, and the top electrode overlap in the thickness direction of the substrate is the effective area of ​​the resonator; and

[0133] A central defect structure is formed in the effective area. In the top view of the resonator, the central defect structure is located in at least a part of the high-temperature area. The thickness and / or material of the central defect structure is different from the layer where the central defect structure is located. The high-temperature area refers to an area with the center of mass of the effective area as the center and r as the radius, and the radius r is 50% of the radius of the equivalent circle of the effective area where the high-temperature area is located. The equivalent circle is: a circle with the center of mass of the effective area as the center and the area of ​​the circle equal to the area of ​​the effective area.

[0134] 3. A filter comprising the above resonator.

[0135] 4. An electronic device, comprising the above-mentioned resonator or the above-mentioned filter. It should be noted that the electronic devices here include but are not limited to intermediate products such as RF front-ends and filter amplifier modules, as well as terminal products such as mobile phones, WIFI, and drones.

[0136] 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, comprising: substrate; Acoustic mirror; bottom electrode; Top electrode; Piezoelectric layer, in: The area where the acoustic mirror, the bottom electrode, the piezoelectric layer, and the top electrode overlap in the thickness direction of the substrate is the effective area of ​​the resonator; and The effective area is formed with a central defect structure, and the central defect structure includes a bulge structure or a concave structure formed by the top electrode or the bottom electrode itself; In the top view of the resonator, the central defect structure is located in the high temperature area of ​​the effective area, and the high temperature area refers to an area with the center of mass of the effective area as the center and r as the radius, and the radius r is 20% of the radius of the equivalent circle of the effective area where the high temperature area is located. The equivalent circle is: a circle with the center of mass of the effective area as the center and the area of ​​the circle is equal to the area of ​​the effective area, wherein: the central defect structure is set to reduce the temperature of the high temperature area of ​​the resonator.

2. The resonator according to claim 1, wherein: The arch structure forms a gap between the top electrode or the bottom electrode and the piezoelectric layer, and the recessed structure forms a concave shape on a side of the top electrode or the bottom electrode away from the piezoelectric layer.

3. The resonator of claim 2, wherein: The thickness of the portion of the top electrode or the bottom electrode forming the arch structure or the recessed structure is the same as the thickness of the other portions.

4. The resonator of claim 2, wherein: The thickness of the gap or the depth of the concave shape is within the range.

5. The resonator of claim 2, wherein: The gap or the concave shape is filled with air or a dielectric material or a metal oxide.

6. The resonator of claim 2, wherein: The gap or the concave shape is filled with a metal having a density greater than that of the electrode material.

7. A bulk acoustic wave resonator, comprising: substrate; Acoustic mirror; bottom electrode; Top electrode; Piezoelectric layer, in: The area where the acoustic mirror, the bottom electrode, the piezoelectric layer, and the top electrode overlap in the thickness direction of the substrate is the effective area of ​​the resonator; and The effective area is formed with a central defect structure, the central defect structure is an electrode filling structure arranged in the top electrode or the bottom electrode, and the density of the metal constituting the electrode filling structure is greater than the density of the corresponding electrode material; The electrode filling structure is arranged in the through hole of the corresponding electrode, and the electrode filling structure is flush with the electrode where it is located; In the top view of the resonator, the central defect structure is located in the high temperature area of ​​the effective area, and the high temperature area refers to an area with the center of mass of the effective area as the center and r as the radius, and the radius r is 20% of the radius of the equivalent circle of the effective area where the high temperature area is located. The equivalent circle is: a circle with the center of mass of the effective area as the center and the area of ​​the circle is equal to the area of ​​the effective area, wherein: the central defect structure is set to reduce the temperature of the high temperature area of ​​the resonator.

8. A bulk acoustic wave resonator, comprising: substrate; Acoustic mirror; bottom electrode; Top electrode; Piezoelectric layer, in: The area where the acoustic mirror, the bottom electrode, the piezoelectric layer, and the top electrode overlap in the thickness direction of the substrate is the effective area of ​​the resonator; and The effective area is formed with a central defect structure, the central defect structure is a piezoelectric layer filling structure arranged in the piezoelectric layer, the piezoelectric layer filling structure at least extends a portion in the thickness direction of the piezoelectric layer, the piezoelectric layer filling structure is arranged in a through hole in the piezoelectric layer and connected to the top electrode and the bottom electrode, and the material of the piezoelectric layer filling structure is selected from air or a non-piezoelectric non-conductive material; In the top view of the resonator, the central defect structure is located in the high temperature area of ​​the effective area, and the high temperature area refers to an area with the center of mass of the effective area as the center and r as the radius, and the radius r is 20% of the radius of the equivalent circle of the effective area where the high temperature area is located. The equivalent circle is: a circle with the center of mass of the effective area as the center and the area of ​​the circle is equal to the area of ​​the effective area, wherein: the central defect structure is set to reduce the temperature of the high temperature area of ​​the resonator.

9. The resonator of claim 8, wherein: The non-piezoelectric non-conductive material includes silicon dioxide, silicon nitride, silicon carbide, aluminum oxide or magnesium oxide.

10. A bulk acoustic wave resonator, comprising: substrate; Acoustic mirror; bottom electrode; Top electrode; Piezoelectric layer, in: The area where the acoustic mirror, the bottom electrode, the piezoelectric layer, and the top electrode overlap in the thickness direction of the substrate is the effective area of ​​the resonator; and The effective region is formed with a central defect structure, and the resonator further comprises an auxiliary layer disposed on the top electrode; The central defect structure includes an arched structure, a concave structure, a convex structure formed by the auxiliary layer itself, or a filling structure arranged in the auxiliary layer; In the top view of the resonator, the central defect structure is located in the high temperature area of ​​the effective area, and the high temperature area refers to an area with the center of mass of the effective area as the center and r as the radius, and the radius r is 20% of the radius of the equivalent circle of the effective area where the high temperature area is located. The equivalent circle is: a circle with the center of mass of the effective area as the center and the area of ​​the circle is equal to the area of ​​the effective area, wherein: the central defect structure is set to reduce the temperature of the high temperature area of ​​the resonator.

11. The resonator according to any one of claims 1 to 10, wherein: In the top view of the resonator, the shape of the central defect structure is circular, square, or polygonal similar to the shape of the effective area.

12. The resonator of claim 11, wherein: In the top view of the resonator, the maximum size of the central defect structure is within the range of 1-50 μm; or within 20% of the length of the longest side of the effective area of ​​the polygonal resonator.

13. The resonator of claim 12, wherein: In the top view of the resonator, the maximum size of the central defect structure is within the range of 1-10 μm; or within 5% of the length of the longest side of the effective area of ​​the polygonal resonator.

14. A bulk acoustic wave resonator, comprising: substrate; Acoustic mirror; bottom electrode; Top electrode; Piezoelectric layer, in: The area where the acoustic mirror, the bottom electrode, the piezoelectric layer, and the top electrode overlap in the thickness direction of the substrate is the effective area of ​​the resonator; and The effective area is formed with a central defect structure, and the central defect structure includes a bulge structure or a concave structure formed by the top electrode or the bottom electrode itself; In the top view of the resonator, the central defect structure is located in the high temperature area, the thickness and / or material of the central defect structure is different from the layer where the central defect structure is located, the high temperature area refers to an area with the center of mass of the effective area as the center and r as the radius, the radius r is 20% of the radius of the equivalent circle of the effective area where the high temperature area is located, and the equivalent circle is: a circle with the center of mass of the effective area as the center and the area of ​​the circle equal to the area of ​​the effective area, wherein: the central defect structure is set to reduce the temperature of the high temperature area of ​​the resonator.

15. A filter comprising: A bulk acoustic wave resonator according to any one of claims 1 to 14. 16 . An electronic device comprising the BAW resonator according to claim 1 , or the filter according to claim 15 .

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