Bulk acoustic resonators and components, electromechanical coupling coefficient difference adjustment methods, filters, electronic equipment

Abstract

This invention relates to a bulk acoustic wave resonator, comprising: a substrate; an acoustic mirror; a bottom electrode; a piezoelectric layer; and a top electrode, wherein: the piezoelectric layer comprises a first layer and a second layer, an acoustic resistive layer is disposed between the first layer and the second layer, the inner edge of the acoustic resistive layer is located inside the boundary of the acoustic mirror in the horizontal direction, the acoustic resistive layer is different from the acoustic resistive layer; and the material of the first layer is different from the material of the second layer. This invention also relates to a bulk acoustic wave resonator assembly, a method for adjusting the electromechanical coupling coefficient of a bulk acoustic wave resonator, a method for adjusting the difference in electromechanical coupling coefficients of resonators in a bulk acoustic wave resonator assembly, a filter, and an electronic device.

Description

Technical Field

[0001] Embodiments of the present invention relate to the semiconductor field, and more particularly to a bulk acoustic wave resonator and its assembly, a method for adjusting the electromechanical coupling coefficient of the bulk acoustic wave resonator, a method for adjusting the difference in electromechanical coupling coefficients of the resonators in the bulk acoustic wave resonator assembly, as well as a filter and an electronic device. Background Technology

[0002] With the rapid development of 5G communication technology, the requirements for data transmission rates are becoming increasingly stringent. Corresponding to these data transmission rates are the high utilization rate of spectrum resources and the increasing complexity of the spectrum. The increasing complexity of communication protocols places stringent demands on the various performance characteristics of radio frequency (RF) systems. In the RF front-end module, RF filters play a crucial role, filtering out out-of-band interference and noise to meet the signal-to-noise ratio requirements of the RF system and communication protocols.

[0003] Traditional radio frequency filters, limited by their structure and performance, cannot meet the requirements of high-frequency communication. Thin-film bulk acoustic resonators (FBARs), as a novel MEMS device, have advantages such as small size, light weight, low insertion loss, wide bandwidth, and high quality factor, making them well-suited for the upgrading of wireless communication systems and making FBAR technology one of the research hotspots in the field of communication.

[0004] In existing filters, the passband characteristics are formed by the combined action of series and parallel resonators. This is achieved by setting different series resonant frequencies for the series resonators and adjusting the electromechanical coupling coefficient Kt of the series resonators. 2 The change in Kt can effectively improve the roll-off characteristics on the right side of the filter's passband. The filter uses a small Kt. 2 Resonators are easy to achieve good roll-off characteristics, but once the design specifications (bandwidth, insertion loss, out-of-band rejection, etc.) are determined, the Kt of the resonator becomes crucial. 2 This essentially confirms that filter bandwidth and good roll-off characteristics are contradictory. Under conventional architectures, it's difficult to achieve good roll-off characteristics in wide-bandwidth filter designs. Furthermore, given the fixed resonator stack in ordinary filters, modifying the resonator structure can reduce the Kt of a 50 Ohm resonator. 2 The change is only around ±0.5%, which has limited improvement on the filter's roll-off characteristics. Therefore, the Kt values ​​between the various resonators are increased. 2 The restriction of degrees of freedom is beneficial to improving the roll-off performance of the entire filter. Summary of the Invention

[0005] The present invention is proposed to alleviate or solve at least one of the above-mentioned problems in the prior art.

[0006] According to one aspect of an embodiment of the present invention, a bulk acoustic resonator is provided, comprising:

[0007] Base;

[0008] Acoustic mirror;

[0009] Bottom electrode;

[0010] piezoelectric layer; and

[0011] Top electrode,

[0012] in:

[0013] The piezoelectric layer includes a first layer and a second layer, with an acoustic resistive layer disposed between the first and second layers. The inner edge of the acoustic resistive layer is located inside the boundary of the acoustic mirror in the horizontal direction, and the acoustic resistive layer is different from the acoustic resistive layer of the piezoelectric layer.

[0014] The material of the first layer is different from the material of the second layer.

[0015] Embodiments of the present invention also relate to a bulk acoustic wave resonator assembly, comprising at least two bulk acoustic wave resonators, wherein at least one bulk acoustic wave resonator is the resonator described above.

[0016] Embodiments of the present invention also relate to a method for adjusting the electromechanical coupling coefficient of a bulk acoustic resonator, the resonator comprising a substrate, an acoustic mirror, a bottom electrode, a piezoelectric layer, and a top electrode, the piezoelectric layer comprising a first layer and a second layer, an acoustic resistive layer disposed between the first layer and the second layer, the method comprising the step of making the materials of the first layer and the second layer different to adjust the electromechanical coupling coefficient.

[0017] Embodiments of the present invention also relate to a method for adjusting the electromechanical coupling coefficient difference of resonators within a bulk acoustic resonator assembly. The assembly includes at least a first resonator and a second resonator. Each resonator includes a substrate, an acoustic mirror, a bottom electrode, a piezoelectric layer, and a top electrode. The piezoelectric layer includes a first layer and a second layer. An acoustic impedance layer is disposed between the first layer and the second layer. The acoustic impedance of the acoustic impedance layer is different from that of the piezoelectric layer. The method includes the steps of: selecting the materials of the first resonator and the first and second layers of the second resonator to adjust the electromechanical coupling coefficient difference between the first resonator and the second resonator.

[0018] Embodiments of the present invention also relate to a filter, including the resonator or component described above.

[0019] Embodiments of the present invention also relate to an electronic device, including the filter described above, the resonator described above, or the component described above. Attached Figure Description

[0020] The following description and accompanying drawings will better aid in understanding these and other features and advantages of the various embodiments disclosed herein, wherein the same reference numerals in the drawings always denote the same parts, wherein:

[0021] Figure 1 This is a top view schematic diagram of a bulk acoustic resonator according to an exemplary embodiment of the present invention;

[0022] Figure 2 For an exemplary embodiment of the present invention, along Figure 1 A schematic diagram of the cross-section of the bulk acoustic resonator of the MOM' line in the diagram;

[0023] Figure 3 An example diagram illustrates the relationship between the width of the AW structure and the electromechanical coupling coefficient;

[0024] Figure 4 Exemplary examples show the relationship between the width of the AW structure and the parallel resonant impedance of the bulk acoustic resonator when the AW structure is disposed in the piezoelectric layer and when the AW structure is disposed between the top electrode and the piezoelectric layer.

[0025] Figure 5A-5G An example is shown Figure 2 A cross-sectional schematic diagram of the fabrication process of a bulk acoustic resonator. Detailed Implementation

[0026] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. In this 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 thereof. These are only some embodiments of the invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0027] First, the reference numerals in the accompanying drawings of this invention are explained as follows:

[0028] 10: Substrate, with optional materials including single-crystal silicon, gallium nitride, gallium arsenide, sapphire, quartz, silicon carbide, diamond, etc.

[0029] 20: Acoustic mirror, which can be a cavity, or it can be a Bragg reflector layer or other equivalent forms. In the embodiments of the present invention, a cavity form is used.

[0030] 20A: Release channel, connecting the release port 90 to the acoustic mirror cavity.

[0031] 21: Sacrificial layer, which is placed in the cavity during the fabrication of the resonator when the acoustic mirror is in the form of a cavity, and is released in the subsequent process to form the acoustic mirror cavity. The sacrificial layer 21 can be made of materials such as silicon dioxide, doped silicon dioxide, polycrystalline silicon, or amorphous silicon.

[0032] 30: Bottom electrode (including bottom electrode pins), the material can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite or alloy of the above metals, etc.

[0033] 41: The first piezoelectric layer can be a single-crystal piezoelectric material, such as single-crystal aluminum nitride, single-crystal gallium nitride, single-crystal lithium niobate, single-crystal lead zirconate titanate (PZT), single-crystal potassium niobate, single-crystal quartz film, or single-crystal lithium tantalate, etc. It can also be a polycrystalline piezoelectric material (as opposed to single-crystal, a non-single-crystal material), such as polycrystalline aluminum nitride, zinc oxide, PZT, etc. It can also be a rare earth element doped with a certain atomic ratio of the above materials. Mixed materials, such as doped aluminum nitride, contain at least one rare earth element, such as scandium (Sc), yttrium (Y), magnesium (Mg), titanium (Ti), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), etc.

[0034] 42: The second piezoelectric layer is made of a different material than the first piezoelectric layer. It can be a monocrystalline piezoelectric material, such as monocrystalline aluminum nitride, monocrystalline gallium nitride, monocrystalline lithium niobate, monocrystalline lead zirconate titanate (PZT), monocrystalline potassium niobate, monocrystalline quartz film, or monocrystalline lithium tantalate, etc. It can also be a polycrystalline piezoelectric material (as opposed to monocrystalline, a non-monocrystalline material), such as polycrystalline aluminum nitride, zinc oxide, PZT, etc., or it can be a material containing certain elements of the above materials. The rare earth element doped material can be, for example, aluminum nitride doped with at least one rare earth element, such as scandium (Sc), yttrium (Y), magnesium (Mg), titanium (Ti), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), etc.

[0035] 50: Top electrode (including top electrode pin), the material can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite or alloy of the above metals, etc.

[0036] 70: Passivation layer or process layer, which can be aluminum nitride, silicon nitride or silicon dioxide, etc.

[0037] 80: Acoustic resistive layer, the acoustic resistivity of which differs from that of the first piezoelectric layer 41 and the second piezoelectric layer 42. In the embodiment illustrated in the present invention, it is in the form of an air gap (i.e., AW), but it can also be in the form of a solid dielectric layer, such as silicon dioxide or its dopants, or silicon nitride or its dopants. As will be understood, the acoustic resistive layer can also be greater than that of the first piezoelectric layer and the second piezoelectric layer.

[0038] 81: Sacrificial layer, which is set at the position corresponding to the air gap during the fabrication of the resonator when the acoustic barrier layer is an air gap. It is released in subsequent processes to form the air gap. The sacrificial layer 81 can be made of materials such as silicon dioxide, doped silicon dioxide, polycrystalline silicon, or amorphous silicon.

[0039] 90: Release hole.

[0040] Figure 1 This is a top view schematic diagram of a bulk acoustic resonator according to an exemplary embodiment of the present invention. Figure 2 For an exemplary embodiment of the present invention, along Figure 1 A schematic diagram of the cross-section of the bulk acoustic resonator of the MM' line.

[0041] exist Figure 1-2 The bulk acoustic resonator includes a substrate 10, an acoustic mirror cavity 20 disposed in the substrate 10, a bottom electrode 30, a top electrode 50, and a piezoelectric layer, the piezoelectric layer including a first piezoelectric layer 41 and a second piezoelectric layer 42. An acoustic resistive layer 80, in the form of an air gap, is disposed between the first piezoelectric layer and the second piezoelectric layer. Figure 1-2 The passivation layer 70 is also shown.

[0042] Figure 4 Exemplary examples show the relationship between the width of the AW structure and the parallel resonant impedance of the bulk acoustic wave resonator when the AW structure is disposed within the piezoelectric layer and when the AW structure is disposed between the top electrode and the piezoelectric layer. Figure 4 In the diagram, the horizontal axis represents the width of the AW structure (in μm), and the vertical axis represents the parallel resonant impedance Rp of the resonator (in ohms). Figure 4 In the diagram, the dashed line indicates the AW structure is positioned between the top electrode and the piezoelectric layer, while the solid line indicates the AW structure is positioned within the piezoelectric layer. For example... Figure 4 As shown, the parallel resonant impedance of the AW structure within the piezoelectric layer is significantly higher than that of the AW structure between the piezoelectric layer and the top electrode. Therefore, by placing an acoustic resistive layer 80 between the first piezoelectric layer 41 and the second piezoelectric layer 42, the performance of the resonator can be effectively improved compared to placing the acoustic resistive layer between the top electrode and the piezoelectric layer.

[0043] By providing an acoustic impedance layer 80 between the first piezoelectric layer 41 and the second piezoelectric layer 42, the electromechanical coupling coefficient of the resonator can also be adjusted. Since the first piezoelectric layer 41 and the second piezoelectric layer 42 are fabricated separately, these two piezoelectric layers can be made of different materials, thus allowing for free adjustment of the resonator's electromechanical coupling coefficient. For example, the first piezoelectric layer 41 may be a piezoelectric layer of a certain material (e.g., a piezoelectric layer of aluminum nitride, zinc oxide, lead zirconate titanate, lithium niobate, quartz, potassium niobate, or lithium tantalate), while the second piezoelectric layer 42 may be a doped layer of the same material as the first piezoelectric layer 41, doped with at least one of the rare earth elements mentioned above. In a specific embodiment, both the first piezoelectric layer 41 and the second piezoelectric layer 42 are based on aluminum nitride piezoelectric materials, but one layer is an undoped piezoelectric material, and the other layer is a scandium-doped piezoelectric material. For example, both the first and second piezoelectric layers are doped layers of the same material, only the doping concentration of the first piezoelectric layer differs from that of the second piezoelectric layer. In one specific embodiment, both the first piezoelectric layer 41 and the second piezoelectric layer 42 are based on aluminum nitride piezoelectric materials doped with the rare earth element scandium, only the doping concentrations of the first and second piezoelectric layers differ. Another example is that the material of the first piezoelectric layer 41 is one of aluminum nitride, zinc oxide, lead zirconate titanate, lithium niobate, quartz, potassium niobate, and lithium tantalate, while the material of the second piezoelectric layer 42 is a material different from that of the first piezoelectric layer, among aluminum nitride, zinc oxide, lead zirconate titanate, lithium niobate, quartz, potassium niobate, and lithium tantalate. In one specific embodiment, the first piezoelectric layer is aluminum nitride, and the second piezoelectric layer is zinc oxide.

[0044] Therefore, in this invention, while improving the resonator performance by setting an AW structure in the piezoelectric layer, different piezoelectric layers can be prepared on the upper and lower sides of the AW structure to achieve free setting of the electromechanical coupling coefficient of the resonator.

[0045] The use of piezoelectric layers 41 and 42 with different doping can significantly adjust the electromechanical coupling coefficient of the resonator. For example, when fabricating a duplexer within the same die, a large difference (greater than 1%) in the electromechanical coupling coefficient of the resonator in the transmit filter Tx and the receive filter Rx is required. However, within either the transmit filter Tx or the receive filter Rx, a smaller difference (less than 1%) in the electromechanical coupling coefficients between different resonators is needed. In this case, the width of the AW structure within the effective region of the resonator can be adjusted, i.e., by adjusting... Figure 2 The widths L1 and L2 of the AW structure in the filter are used to adjust the electromechanical coupling coefficient of the resonator inside the filter. For example... Figure 2As shown, L1 is the width of the AW structure at the non-electrode connection end of the top electrode, which is the horizontal distance between the non-electrode connection end of the top electrode and the inner edge of the AW structure; L2 is the width of the AW structure at the electrode connection end of the top electrode, which is the horizontal distance between the acoustic mirror boundary and the inner edge of the AW structure at the connection end of the top electrode. In one embodiment of the present invention, L1 and L2 may be the same or different, but both are within the range of 0.25-10 μm.

[0046] Figure 3 An exemplary diagram illustrates the relationship between the width of the AW structure or air gap and the electromechanical coupling coefficient. In Figure 3 In the figure, the horizontal axis represents the width of the AW structure (in μm), and the vertical axis represents the electromechanical coupling coefficient. Figure 3 This indicates the effect of the width of the AW structure of the resonator on the electromechanical coupling coefficient when the width of the AW structure on each side of the effective region of the resonator is the same. Figure 3 As shown, the electromechanical coupling coefficient gradually decreases with the increase of the AW width. Therefore, the electromechanical coupling coefficient of the resonator can be adjusted by regulating the width of the AW structure.

[0047] For a resonator whose effective region is a polygon, the width of the AW structure on each side can be the same or different.

[0048] In this invention, the AW structure, acoustic resistive layer, or air gap is disposed at the non-electrode connection end of the top electrode. When the effective region of the resonator is polygonal, this can include the AW structure, acoustic resistive layer, or air gap being disposed on only one or more sides of the non-electrode connection end, or it can include the AW structure, acoustic resistive layer, or air gap being disposed on all sides of the non-electrode connection end. In this invention, the AW structure, acoustic resistive layer, or air gap being disposed at the electrode connection end of the top electrode, when the effective region of the resonator is polygonal, indicates that the AW structure, acoustic resistive layer, or air gap is disposed on the side where the electrode connection end of the top electrode is located. The AW structure, acoustic resistive layer, or air gap can also be disposed around the entire effective region of the resonator.

[0049] When the thickness of the piezoelectric layer is constant, and the same piezoelectric material is used on both the top and bottom sides of the AW structure, the electromechanical coupling coefficient of the resonator is a fixed value under the same conditions, regardless of the location of the AW structure within the piezoelectric layer. However, using different piezoelectric layer materials on the top and bottom sides of the AW structure increases the design freedom of the resonator's electromechanical coupling coefficient. For example, the first piezoelectric layer 41 uses undoped aluminum nitride, and the second piezoelectric layer 42 uses scandium-doped aluminum nitride. When the piezoelectric layer thickness is fixed, for example, when only undoped aluminum nitride is used, the electromechanical coupling coefficient is 6%, while when only doped aluminum nitride is used, the electromechanical coupling coefficient is 10%. Therefore, with a constant piezoelectric layer thickness, the electromechanical coupling coefficient of the resonator can be freely varied between 6% and 10% by controlling the doping concentration of the first piezoelectric layer 41 and the second piezoelectric layer 42. Once the thicknesses of the two piezoelectric layers are determined, the electromechanical coupling coefficients of different resonators within the filter can be fine-tuned by controlling the change in the width of the AW structure. Therefore, this scheme can maximize the design freedom of the electromechanical coupling coefficients of the resonators within the filter.

[0050] In this invention, the electromechanical coupling coefficient of the resonator can be adjusted by selecting the materials of the first piezoelectric layer and the second piezoelectric layer. For two resonators, the difference between their electromechanical coupling coefficients can be varied between 0% and 10% in the manner described above.

[0051] exist Figure 2 In this design, the first piezoelectric layer 41 and the second piezoelectric layer 42 are made of different materials. When the thicknesses of the first piezoelectric layer 41 and the second piezoelectric layer 42 are fixed, for a certain electromechanical coupling coefficient of the resonator, the required electromechanical coupling coefficient can be achieved by changing the materials of the piezoelectric layers. Once the doping or materials of the first piezoelectric layer 41 and the second piezoelectric layer 42 are determined, the desired electromechanical coupling coefficient can be achieved by changing... Figure 2 The widths L1 and L2 in the diagram are used to further adjust the electromechanical coupling coefficient of the resonator.

[0052] Figure 2 The diagram also shows the thicknesses of the first piezoelectric layer 41 and the second piezoelectric layer 42, which are H1 and H2, respectively. The proportions of the two different piezoelectric materials can be adjusted by regulating the ratio of H1 to H2, thereby adjusting the electromechanical coupling coefficient of the resonator. Similarly, once H2 and H1 are determined, the electromechanical coupling coefficient can be adjusted by changing... Figure 2 The widths L1 and L2 in the diagram are used to further adjust the electromechanical coupling coefficient of the resonator.

[0053] like Figure 2 As shown, the position of the AW structure sandwiched between the first piezoelectric layer 41 and the second piezoelectric layer 42 is not fixed. In one embodiment of the invention, the distance between the lower surface of the AW structure and the lower surface of the first piezoelectric layer 41 is greater than... The distance between the upper surface of the AW structure and the second piezoelectric layer 42 is also greater than... The thickness range of AW structure is

[0054] The following reference Figure 5A-5G Exemplary Description Figure 2 The fabrication process of a bulk acoustic resonator.

[0055] First, such as Figure 5A As shown, a cavity serving as an acoustic mirror 20 is formed on the upper surface of the substrate 10. Then, a sacrificial material is placed on the upper surface of the substrate 10 to fill the cavity. Then, the sacrificial material on the upper surface of the substrate 10 is removed by a CMP (chemical mechanical polishing) process, and the upper surface of the sacrificial material in the cavity is flush with the upper surface of the substrate 10 to form a sacrificial layer 21.

[0056] Second, such as Figure 5B As shown, in Figure 5A The electrode material layer is deposited and patterned on the structure to form the bottom electrode 30.

[0057] Third, such as Figure 5C As shown, in Figure 5B A first piezoelectric layer 41 is deposited on the structure, which may be, for example, an undoped piezoelectric layer.

[0058] Fourth, such as Figure 5D As shown, in Figure 5C A sacrificial material is deposited and patterned on the upper surface of the first piezoelectric layer 41 to form a sacrificial layer 81. This sacrificial layer 81 will be released later to form the AW structure 80.

[0059] Fifth, such as Figure 5E As shown, in Figure 5D A second piezoelectric layer 42 is deposited on the upper surface of the structure, which may be, for example, a doped piezoelectric layer.

[0060] Sixth, such as Figure 5F As shown, in Figure 5E A top electrode 50 and a protective layer or passivation layer 70 are prepared on the upper surface of the structure.

[0061] Seventh, release sacrificial layer 21 and sacrificial layer 81 to form acoustic mirror 20 and AW structure 80 respectively, as shown. Figure 5G As shown.

[0062] It should be noted that, in this invention, each numerical range, except where explicitly stated not to include endpoint values, can be either an endpoint value or the median of each numerical range, and all of these are within the protection scope of this invention.

[0063] In this invention, "upper" and "lower" are relative to the bottom surface of the base. For a component, the side closer to the bottom surface is the lower side, and the side farther from the bottom surface is the upper side.

[0064] In this invention, "inner" and "outer" refer to the center of the effective region of the resonator (the overlapping area of ​​the piezoelectric layer, top electrode, bottom electrode, and acoustic mirror in the thickness direction of the resonator constitutes the effective region) in the lateral or radial direction. A side or end of a component closer to the center of the effective region is called the inner side or inner end, while a side or end of the component farther from the center of the effective region is called the outer side or outer end. For a reference position, being inside the position means being between that position and the center of the effective region in the lateral or radial direction, while being outside the position means being farther from the center of the effective region in the lateral or radial direction than that position.

[0065] As will be understood by those skilled in the art, bulk acoustic resonators can be used to form filters or other semiconductor devices.

[0066] Based on the above, the present invention proposes the following technical solution:

[0067] 1. A bulk acoustic resonator, comprising:

[0068] Base;

[0069] Acoustic mirror;

[0070] Bottom electrode;

[0071] piezoelectric layer; and

[0072] Top electrode,

[0073] in:

[0074] The piezoelectric layer includes a first layer and a second layer, with an acoustic resistive layer disposed between the first and second layers. The inner edge of the acoustic resistive layer is located inside the boundary of the acoustic mirror in the horizontal direction, and the acoustic resistive layer is different from the acoustic resistive layer of the piezoelectric layer.

[0075] The material of the first layer is different from the material of the second layer.

[0076] 2. The resonator according to 1, wherein:

[0077] The acoustic resistive layer includes a non-connection end acoustic resistive layer at the non-electrode connection end of the top electrode, and the inner edge of the non-connection end acoustic resistive layer is located inside the non-electrode connection end of the top electrode in the horizontal direction.

[0078] 3. The resonator according to 2, wherein:

[0079] The non-electrode connection end of the top electrode is located inside the boundary of the acoustic mirror or flush with the boundary of the acoustic mirror in the horizontal direction;

[0080] In the horizontal direction, there is a first distance between the non-electrode connection end of the top electrode and the inner edge of the acoustic resist layer of the non-connection end, the first distance being in the range of 0.25-10μm.

[0081] 4. The resonator according to any one of 1-3, wherein:

[0082] The acoustic resist layer includes a connection end acoustic resist layer at the electrode connection end of the top electrode.

[0083] 5. The resonator according to 4, wherein:

[0084] In the horizontal direction, there is a second distance between the boundary of the acoustic mirror and the inner edge of the acoustic resist layer at the connection end, and the second distance is in the range of 0.25-10μm.

[0085] 6. The resonator according to claim 1, wherein:

[0086] The thickness of the first layer is different from the thickness of the second layer.

[0087] 7. The resonator according to claim 1, wherein:

[0088] The acoustic resistive layer is a void layer or a solid dielectric layer.

[0089] 8. The resonator according to any one of 1-7, wherein:

[0090] One of the first and second layers is a doped layer of the other; or

[0091] The first and second layers are both doped layers of the same material, but the doping concentration of the first layer is different from that of the second layer.

[0092] 9. The resonator according to any one of 1-7, wherein:

[0093] The first layer is made of one of the following materials: aluminum nitride, zinc oxide, lead zirconate titanate, lithium niobate, quartz, potassium niobate, and lithium tantalate. The second layer is made of a different material from the first layer among aluminum nitride, zinc oxide, lead zirconate titanate, lithium niobate, quartz, potassium niobate, and lithium tantalate.

[0094] 10. A bulk acoustic resonator assembly, comprising:

[0095] At least two bulk acoustic resonators, wherein at least one bulk acoustic resonator is a resonator according to any one of 1-9.

[0096] 11. The component according to 10, wherein:

[0097] The at least two bulk acoustic resonators include a first resonator and a second resonator.

[0098] Both the first resonator and the second resonator are resonators according to any one of 1-9.

[0099] 12. The component according to 11, wherein:

[0100] The first and second resonators are resonators as described in 8 or 9.

[0101] 13. The component according to 12, wherein:

[0102] The difference between the electromechanical coupling coefficient of the first resonator and the electromechanical coupling coefficient of the second resonator is in the range of 0%-10%.

[0103] 14. The component according to any one of 10-13, wherein:

[0104] Both the first and second resonators are resonators based on 3 or 5.

[0105] The widths of the acoustic resist layer of the first resonator and the corresponding acoustic resist layer of the second resonator are different.

[0106] 15. A method for adjusting the electromechanical coupling coefficient of a bulk acoustic resonator, the resonator comprising a substrate, an acoustic mirror, a bottom electrode, a piezoelectric layer, and a top electrode, the piezoelectric layer comprising a first layer and a second layer, wherein an acoustic resistive layer is disposed between the first layer and the second layer, the method comprising the steps of:

[0107] The materials of the first and second layers are different to adjust the electromechanical coupling coefficient.

[0108] 16. The method according to 15 further includes the step of:

[0109] Adjust the height of the first and second layers to adjust the electromechanical coupling coefficient.

[0110] 17. The method according to 15 or 16 further includes the step of:

[0111] Adjust the width of the acoustic resist layer to further adjust the electromechanical coupling coefficient, wherein: the width of the acoustic resist layer, if at the non-electrode connection end of the top electrode, is the horizontal distance between the non-electrode connection end of the top electrode and the inner edge of the acoustic resist layer, and if at the electrode connection end of the top electrode, is the horizontal distance between the boundary of the acoustic mirror and the inner edge of the acoustic resist layer.

[0112] 18. A method for adjusting the electromechanical coupling coefficient difference of resonators within a bulk acoustic wave resonator assembly, the assembly comprising at least a first resonator and a second resonator, each resonator comprising a substrate, an acoustic mirror, a bottom electrode, a piezoelectric layer, and a top electrode, the piezoelectric layer comprising a first layer and a second layer, an acoustic resistive layer disposed between the first layer and the second layer, the acoustic resistive layer being different from the acoustic resistive layer of the corresponding piezoelectric layer, the method comprising the steps of:

[0113] The materials of the first layer and the second layer of the first resonator and the second resonator are selected to adjust the difference in electromechanical coupling coefficient between the first resonator and the second resonator.

[0114] 19. The method according to 18 further includes the step of:

[0115] Adjust the height of the first and / or second layers of the first and / or second resonator to adjust the difference in electromechanical coupling coefficient between the first and second resonators.

[0116] 20. The method according to 18 or 19, wherein:

[0117] The component includes a first filter and a second filter, the first filter including a first resonator and the second filter including a second resonator;

[0118] The method includes the steps of: selecting the materials of the first and second layers of the resonator in the first filter, and selecting the materials of the first and second layers of the resonator in the second filter, so as to adjust the difference between the electromechanical coupling coefficient of the resonator in the first filter and the electromechanical coupling coefficient of the resonator in the second filter.

[0119] 21. The method according to 20 further includes the step of:

[0120] Adjusting the width of the acoustic resist layer in the first filter to further adjust the difference in electromechanical coupling coefficients between different resonators within the first filter, and / or adjusting the width of the acoustic resist layer in the second filter to further adjust the difference in electromechanical coupling coefficients between different resonators within the second filter.

[0121] Wherein: the width of the acoustic resist layer, if at the non-electrode connection end of the top electrode, is the horizontal distance between the non-electrode connection end of the top electrode and the inner edge of the acoustic resist layer; if at the electrode connection end of the top electrode, it is the horizontal distance between the boundary of the acoustic mirror and the inner edge of the acoustic resist layer.

[0122] 22. A filter comprising a bulk acoustic resonator according to any one of 1-9, or a bulk acoustic resonator assembly according to any one of 10-14.

[0123] 23. An electronic device comprising the filter according to claim 22, or the bulk acoustic resonator according to any one of claims 1-9, or the bulk acoustic resonator assembly according to any one of claims 10-14.

[0124] The electronic devices mentioned here include, but are not limited to, intermediate products such as radio frequency front-ends and filtering and amplification modules, as well as terminal products such as mobile phones, WIFI, and drones.

[0125] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that variations 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 resonator, comprising: Base; Acoustic mirror; Bottom electrode; piezoelectric layer; and Top electrode, in: The piezoelectric layer includes a first layer and a second layer, with an acoustic resistive layer disposed between the first and second layers. The inner edge of the acoustic resistive layer is located inside the boundary of the acoustic mirror in the horizontal direction, and the acoustic resistive layer is different from the acoustic resistive layer of the piezoelectric layer. The width of the acoustic resistive layer is negatively correlated with the electromechanical coupling coefficient of the resonator. Since the material of the first layer is different from that of the second layer, the electromechanical coupling coefficient of the bulk acoustic resonator can be adjusted by adjusting the width of the acoustic resistive layer.

2. The resonator according to claim 1, wherein: The acoustic resistive layer includes a non-connection end acoustic resistive layer at the non-electrode connection end of the top electrode, and the inner edge of the non-connection end acoustic resistive layer is located inside the non-electrode connection end of the top electrode in the horizontal direction.

3. The resonator according to claim 2, wherein: The non-electrode connection end of the top electrode is located inside the boundary of the acoustic mirror or flush with the boundary of the acoustic mirror in the horizontal direction; In the horizontal direction, there is a first distance between the non-electrode connection end of the top electrode and the inner edge of the acoustic resist layer of the non-connection end, the first distance being in the range of 0.25-10μm.

4. The resonator according to any one of claims 1-3, wherein: The acoustic resistive layer includes a connection end acoustic resistive layer at the electrode connection end of the top electrode.

5. The resonator according to claim 4, wherein: In the horizontal direction, there is a second distance between the boundary of the acoustic mirror and the inner edge of the acoustic resist layer at the connection end, and the second distance is in the range of 0.25-10μm.

6. The resonator according to claim 1, wherein: The thickness of the first layer is different from the thickness of the second layer.

7. The resonator according to claim 1, wherein: The acoustic resistive layer is a void layer or a solid dielectric layer.

8. The resonator according to any one of claims 1-3 and 5-7, wherein: One of the first and second layers is a doped layer of the other; or The first and second layers are both doped layers of the same material, but the doping concentration of the first layer is different from that of the second layer.

9. The resonator according to any one of claims 1-3 and 5-7, wherein: The first layer is made of one of the following materials: aluminum nitride, zinc oxide, lead zirconate titanate, lithium niobate, quartz, potassium niobate, and lithium tantalate. The second layer is made of a different material from the first layer among aluminum nitride, zinc oxide, lead zirconate titanate, lithium niobate, quartz, potassium niobate, and lithium tantalate.

10. A bulk acoustic resonator assembly, comprising: At least two bulk acoustic resonators, wherein at least one bulk acoustic resonator is a resonator according to any one of claims 1-9.

11. The component of claim 10, wherein: The at least two bulk acoustic resonators include a first resonator and a second resonator. Both the first resonator and the second resonator are resonators according to any one of claims 1-9.

12. The component of claim 11, wherein: The first resonator and the second resonator are the resonators according to claim 8 or 9.

13. The component of claim 12, wherein: The difference between the electromechanical coupling coefficient of the first resonator and the electromechanical coupling coefficient of the second resonator is in the range of 0%-10%.

14. The component according to any one of claims 11-13, wherein: Both the first resonator and the second resonator are resonators according to claim 3 or 5. The widths of the acoustic resist layer of the first resonator and the corresponding acoustic resist layer of the second resonator are different.

15. A method for adjusting the electromechanical coupling coefficient of a bulk acoustic resonator, the resonator comprising a substrate, an acoustic mirror, a bottom electrode, a piezoelectric layer, and a top electrode, the piezoelectric layer comprising a first layer and a second layer, an acoustic resistive layer disposed between the first layer and the second layer, the width of the acoustic resistive layer being negatively correlated with the electromechanical coupling coefficient of the resonator, the method comprising the steps of: The materials of the first and second layers are different to adjust the electromechanical coupling coefficient; Adjust the width of the acoustic barrier layer to further adjust the electromechanical coupling coefficient.

16. The method of claim 15, further comprising the step of: Adjust the height of the first and second layers to adjust the electromechanical coupling coefficient.

17. The method according to claim 15 or 16, wherein the width of the acoustic resist layer, if at the non-electrode connection end of the top electrode, is the horizontal distance between the non-electrode connection end of the top electrode and the inner edge of the acoustic resist layer, and if at the electrode connection end of the top electrode, is the horizontal distance between the boundary of the acoustic mirror and the inner edge of the acoustic resist layer.

18. A method for adjusting the electromechanical coupling coefficient difference of resonators within a bulk acoustic resonator assembly, the assembly comprising at least a first resonator and a second resonator, each resonator comprising a substrate, an acoustic mirror, a bottom electrode, a piezoelectric layer, and a top electrode, the piezoelectric layer comprising a first layer and a second layer, an acoustic resistive layer disposed between the first layer and the second layer, the acoustic resistive layer having an acoustic resistive different from that of the corresponding piezoelectric layer, the width of the acoustic resistive layer being negatively correlated with the electromechanical coupling coefficient of the resonator, the method comprising the steps of: The materials of the first layer and the second layer of the first resonator and the second resonator are selected to adjust the difference in electromechanical coupling coefficient between the first resonator and the second resonator. Adjust the width of the acoustic resist layer to further adjust the electromechanical coupling coefficient of the first resonator and / or the second resonator.

19. The method of claim 18, further comprising the step of: Adjust the height of the first and / or second layers of the first and / or second resonator to adjust the difference in electromechanical coupling coefficient between the first and second resonators.

20. The method according to claim 18 or 19, wherein: The component includes a first filter and a second filter, wherein the first filter includes a first resonator and the second filter includes a second resonator; The method includes the steps of: selecting the materials of the first and second layers of the resonator in the first filter, and selecting the materials of the first and second layers of the resonator in the second filter, so as to adjust the difference between the electromechanical coupling coefficient of the resonator in the first filter and the electromechanical coupling coefficient of the resonator in the second filter.

21. The method of claim 20, further comprising the step of: Adjusting the width of the acoustic resist layer in the first filter to further adjust the difference in electromechanical coupling coefficients between different resonators within the first filter, and / or adjusting the width of the acoustic resist layer in the second filter to further adjust the difference in electromechanical coupling coefficients between different resonators within the second filter. in: The width of the acoustic resist layer, if at the non-electrode connection end of the top electrode, is the horizontal distance between the non-electrode connection end of the top electrode and the inner edge of the acoustic resist layer; if at the electrode connection end of the top electrode, it is the horizontal distance between the boundary of the acoustic mirror and the inner edge of the acoustic resist layer.

22. A filter comprising a bulk acoustic resonator according to any one of claims 1-9, or a bulk acoustic resonator assembly according to any one of claims 10-14.

23. An electronic device comprising the filter of claim 22, or the bulk acoustic resonator of any one of claims 1-9, or the bulk acoustic resonator assembly of any one of claims 10-14.

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