Elastic wave resonator and communication equipment

Abstract

The invention relates to the technical field of microelectronics, in particular to an elastic wave resonator and communication equipment. The elastic wave resonator at least comprises a piezoelectric film. The top electrode is positioned on the piezoelectric film; the top electrode is an interdigital electrode; the interdigital electrode comprises a first bus bar and a second bus bar which are arranged at an interval along a first direction, and a first electrode finger and a second electrode finger which are arranged in a staggered manner along a second direction; the first electrode fingers are connected with the first bus bar, and the second electrode fingers are connected with the second bus bar; the second direction is a sound wave propagation direction of the elastic wave resonator and is perpendicular to the first direction; connecting parts are arranged at the joints of part of electrode fingers in the top electrode and the adjacent bus bars; and a first preset angle is formed between the connecting part and the correspondingly connected electrode finger. Therefore, the electric field distribution and the stress distribution of the transverse high-order mode can be changed, the coupling coefficient of the transverse high-order mode is reduced, and the effect of suppressing the transverse high-order mode is achieved.

Description

Technical Field

[0001] The present invention relates to the field of microelectronic technology, and in particular to an elastic wave resonator and communication equipment. Background Art

[0002] Modern wireless communication systems require filters to have flat passbands, steep skirts, and high out-of-band suppression, and require resonators to have clean spectral responses and high Q values. However, surface acoustic wave (SAW) filter technology and plate wave (Plate Wave) filter technology are usually composed of piezoelectric materials and interdigital electrodes. Their finite apertures will lead to the generation of lateral high-order modes, resulting in ripples in the passband of the corresponding filters. For example, inclined electrode structures and apodization structures usually increase the difficulty of device layout or reduce the Q value of the device. Therefore, how to provide an elastic wave resonator that can weaken lateral high-order modes without sacrificing Q value or changing the shape of the device has become a technical problem that needs to be solved urgently. Summary of the invention

[0003] In order to solve the above technical problems, the present application discloses an elastic wave resonator, which at least comprises:

[0004] Piezoelectric film;

[0005] and a top electrode located on the piezoelectric film; the top electrode is an interdigitated electrode; the interdigitated electrode includes a first bus bar and a second bus bar spaced apart along a first direction, and a first electrode finger and a second electrode finger staggered along a second direction; the first electrode finger is connected to the first bus bar, and the second electrode finger is connected to the second bus bar; the second direction is the direction of propagation of the acoustic wave of the elastic wave resonator, and is perpendicular to the first direction;

[0006] Wherein, a connection portion is provided at a connection point between some electrode fingers in the top electrode and an adjacent bus bar; and a first preset angle exists between the connection portion and the correspondingly connected electrode finger.

[0007] Optionally, corresponding locations of at least (1 / 4)N electrode fingers in the top electrode are provided with connecting portions; N is the total number of electrode fingers included in the top electrode.

[0008] Optionally, angles between the connecting portions in the top electrode and the first direction are not all equal.

[0009] Optionally, the connecting portion includes at least two sub-connecting segments, and a second preset angle exists between adjacent sub-connecting segments.

[0010] Optionally, the length of the connecting portion along the first direction ranges from 0.05λ to 0.2L; λ is the distance between the centers of adjacent electrode fingers on the same bus bar; L is the length of the aperture region of the top electrode along the first direction; the aperture region is the area where the first electrode finger and the second electrode finger overlap.

[0011] Optionally, the top electrode further includes an extension portion;

[0012] At least some of the electrode fingers in the top electrode have extensions at their ends; and a third preset angle exists between the extensions and the corresponding electrode fingers.

[0013] Optionally, angles between the extensions in the top electrode and the first direction are not all equal.

[0014] Optionally, the extension portion includes at least two sub-extension segments, and a fourth preset angle exists between adjacent sub-extension segments.

[0015] Optionally, in the top electrode, the angles between each extension portion and the first direction are all equal, and the angles between each connection portion and the first direction are all equal.

[0016] Optionally, the shape of the connecting portion includes any one of a straight line shape, a broken line shape and an arc shape, or a combination of two thereof;

[0017] The shape of the extension portion includes any one of a straight line shape, a broken line shape and an arc shape, or a combination of two thereof.

[0018] Optionally, the top electrode further includes a dummy finger electrode;

[0019] A dummy finger electrode is provided between the end of at least part of the electrode fingers in the top electrode and the bus bar on the opposite side.

[0020] Optionally, the angles between the pseudo-finger electrodes in the top electrode and the first direction are not all equal;

[0021] The shape of the pseudo-finger electrode includes any one of a straight line shape, a folded line shape and an arc shape, or a combination of two of them.

[0022] Optionally, the direction of propagation of the sound wave does not coincide with the axis at which the in-plane sound velocity of the piezoelectric film takes an extreme value.

[0023] Optionally, the extension portion is located in an air gap region; the air gap region is a region between a free end of an electrode finger and a bus bar on an opposite side of the electrode finger;

[0024] The air gap region includes a first region, a second region and a third region which are distributed and connected in sequence along the second direction;

[0025] The second area is provided with a pseudo-finger electrode and a bridge member;

[0026] A third region is provided between one end of the dummy electrode and an adjacent bus bar;

[0027] A first region is provided between the other end of the dummy electrode and the end of the target first electrode finger or the end of the extension of the target first electrode finger;

[0028] One end of the bridge is connected to one end of the dummy electrode, and the other end of the bridge is connected to a target second electrode finger; the target second electrode finger is a second electrode finger adjacent to the target first electrode finger.

[0029] Optionally, the top electrode further comprises two reflection grids;

[0030] A reflection grid is provided on both sides of the interdigital electrode.

[0031] Optionally, further comprising a bottom electrode;

[0032] The bottom electrode is located below the piezoelectric film.

[0033] Optionally, the bottom electrode is a surface electrode;

[0034] or,

[0035] The bottom electrode is a forked electrode; each electrode finger of the bottom electrode corresponds to each electrode finger of the top electrode one by one, and the offset distance between the electrode fingers in the bottom electrode corresponding to the electrode fingers of the top electrode does not exceed 20% of the width of the electrode fingers of the top electrode.

[0036] Optionally, a dielectric layer is also included;

[0037] The dielectric is located below the piezoelectric film;

[0038] The dielectric layer is a single-layer material or a multi-layer material;

[0039] The dielectric layer includes one or more of silicon oxide, silicon nitride, polysilicon, amorphous silicon, aluminum oxide, and aluminum nitride, or the dielectric layer is one or more of a temperature compensation layer, a heat dissipation layer, a trap-rich layer, a bonding layer, and a low acoustic velocity layer.

[0040] Optionally, it also includes a supporting substrate;

[0041] The supporting substrate is located below the piezoelectric film;

[0042] The supporting substrate includes one of various crystal forms of sapphire, silicon, spinel, silicon carbide, diamond, diamond-like carbon, silicon nitride, boron nitride, boron carbide, quartz, germanium, aluminum nitride, silicon nitride, yttrium aluminum garnet, lithium tantalate, and lithium niobate.

[0043] Optionally, the support substrate includes a stacked support structure and a high acoustic velocity layer;

[0044] The high sound velocity layer is a material that is easy to shape and process;

[0045] The material of the support structure includes any one of quartz, silicon, sapphire, spinel, and yttrium aluminum garnet;

[0046] The material of the high acoustic velocity layer includes any one of silicon carbide, diamond, diamond-like carbon, aluminum oxide, aluminum nitride, boron nitride, boron carbide and silicon nitride in different crystal forms and different cuts.

[0047] Optionally, a Bragg reflection layer is further provided between the piezoelectric film and the supporting substrate.

[0048] Optionally, the material of the top electrode is a conductive material;

[0049] The conductive material includes one or more combinations of copper, aluminum, gold, silver, tungsten, platinum, nickel, chromium, molybdenum, titanium, graphene, copper-aluminum alloy, aluminum-silicon alloy, doped silicon, silicon carbide, and gallium nitride.

[0050] The present application further discloses a communication device in another aspect, which includes the elastic wave resonator mentioned above;

[0051] The communication device includes at least one of a filter, a duplexer, and a multiplexer.

[0052] The embodiment of the present application provides an elastic wave resonator, which at least includes a piezoelectric film; and a top electrode located on the piezoelectric film; the top electrode is a forked electrode; the forked electrode includes a first bus bar and a second bus bar spaced apart along a first direction, and a first electrode finger and a second electrode finger staggered along a second direction; the first electrode finger is connected to the first bus bar, and the second electrode finger is connected to the second bus bar; the second direction is the sound wave propagation direction of the elastic wave resonator, and is perpendicular to the first direction; wherein, a connection portion is provided at the connection between some electrode fingers in the top electrode and the adjacent bus bar; and there is a first preset angle between the connection portion and the corresponding connected electrode finger. By setting the connection between the electrode finger in the top electrode and the adjacent bus bar into a curved structure, the electric field distribution and the stress distribution of the transverse high-order mode can be changed, so that the coupling coefficient of the transverse high-order mode is reduced, thereby achieving the purpose of suppressing the transverse high-order mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0054] Figure 1 is a cross-sectional view of an exemplary first elastic wave resonator of the present application;

[0055] Figure 2 yes Figure 1A top view of the elastic wave resonator shown;

[0056] Figure 3 is a top view of an exemplary first top electrode of the present application;

[0057] Figure 4 is a top view of an exemplary second top electrode of the present application;

[0058] Figure 5 is a cross-sectional view of an exemplary second elastic wave resonator of the present application;

[0059] Figure 6 is a cross-sectional view of a third exemplary elastic wave resonator of the present application;

[0060] Figure 7 is a cross-sectional view of a fourth exemplary elastic wave resonator of the present application;

[0061] Figure 8 is a cross-sectional view of a fifth exemplary elastic wave resonator of the present application;

[0062] Fig. 9 is a cross-sectional view of a sixth exemplary elastic wave resonator of the present application;

[0063] Fig.10 is a cross-sectional view of a seventh exemplary elastic wave resonator of the present application;

[0064] Fig.11 is a cross-sectional view of an eighth exemplary elastic wave resonator of the present application;

[0065] Fig.12 is a cross-sectional view of a ninth exemplary elastic wave resonator of the present application;

[0066] Fig.13 is a cross-sectional view of a tenth exemplary elastic wave resonator of the present application;

[0067] Fig.14 is a cross-sectional view of an eleventh exemplary elastic wave resonator of the present application;

[0068] Fig.15 is a top view of a top electrode of a conventional elastic wave resonator;

[0069] Fig.16 is an admittance / conductance curve corresponding to comparative example 1;

[0070] Fig.17 is the vibration mode diagram corresponding to Example 1;

[0071] Fig.18 is an admittance / conductance curve corresponding to Example 1;

[0072] Fig.19 is a comparison diagram of the Bode-Q curves of Example 1 and Comparative Example 1;

[0073] Fig. 20 is the vibration mode diagram corresponding to Example 1;

[0074] Fig.21 is a top view of a third exemplary top electrode of the present application;

[0075] Fig. 22 is a top view of a fourth exemplary top electrode of the present application;

[0076] Fig.23 is a top view of an exemplary fifth top electrode of the present application;

[0077] Fig.24 is a top view of a sixth exemplary top electrode of the present application;

[0078] Fig.25 is an admittance / conductance curve corresponding to Example 2;

[0079] Fig.26 is a comparison diagram of the Bode-Q curves of Example 1 and Example 2;

[0080] Fig. 27 is a top view of a seventh exemplary top electrode of the present application;

[0081] Fig.28 is a top view of an exemplary eighth top electrode of the present application;

[0082] Fig.29 is an admittance / conductance curve corresponding to Example 3;

[0083] Fig.30 is a comparison diagram of the Bode-Q curves of Example 2 and Example 3;

[0084] Fig.31 is a top view of a ninth exemplary top electrode of the present application;

[0085] Fig.32 is a top view of a tenth exemplary top electrode of the present application;

[0086] Fig.33 is a top view of an eleventh exemplary top electrode of the present application;

[0087] Fig.34 is an admittance / conductance curve corresponding to Example 4;

[0088] Fig.35 is the Bode-Q curve corresponding to Example 4;

[0089] Fig.36is a top view of a twelfth exemplary top electrode of the present application;

[0090] Fig.37 is a top view of a thirteenth exemplary top electrode of the present application;

[0091] Fig.38 is a top view of a fourteenth exemplary top electrode of the present application;

[0092] Fig.39 is a top view of a fifteenth exemplary top electrode of the present application;

[0093] Fig.40 is a top view of a sixteenth exemplary top electrode of the present application;

[0094] Fig.41 4 is a top view of the seventeenth exemplary top electrode of the present application.

[0095] The following is a supplementary description of the attached drawings:

[0096] 1-piezoelectric film; 2-top electrode; 201-first bus bar; 202-second bus bar; 203-first electrode finger; 204-second electrode finger; 205-bridging member; 206-connecting portion; 2061-sub-connecting section; 207-extension portion; 2071-sub-extension section; 208-dummy electrode; 209-aperture region; 210-air gap region; 2101-first region; 2102-second region; 2103-third region; 211-interdigitated electrode; 3-reflection grid; 301-reflection bar; 302-third bus bar; 303-fourth bus bar; 4-support substrate; 5-dielectric layer; 6-Bragg reflection layer; 7-bottom electrode. DETAILED DESCRIPTION

[0097] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0098] The term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present application. In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may include one or more of the features explicitly or implicitly. Moreover, the terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here.

[0099] When a numerical range is disclosed herein, the above range is deemed to be continuous and includes the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all sub-ranges included therein. For example, a specified range from "1 to 10" should be deemed to include any and all sub-ranges between a minimum of 1 and a maximum of 10. Exemplary sub-ranges of ranges 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, etc.

[0100] See also Figure 1 and Figure 2 , Figure 1 is a cross-sectional view of an exemplary first elastic wave resonator of the present application; Figure 2 yes Figure 1A top view of the corresponding top electrode. The embodiment of the present application discloses an elastic wave resonator, which at least includes: a piezoelectric film 1; and a top electrode 2 located on the piezoelectric film 1; the top electrode 2 is a forked electrode 211; the forked electrode 211 includes a first bus bar 201 and a second bus bar 202 spaced apart along a first direction, and a first electrode finger 203 and a second electrode finger 204 staggered along a second direction; the first electrode finger 203 is connected to the first bus bar 201, and the second electrode finger 204 is connected to the second bus bar 202; the second direction is the direction of propagation of sound waves of the elastic wave resonator, and is perpendicular to the first direction; wherein, a connection portion 206 is provided at the connection between some electrode fingers in the top electrode 2 and the adjacent bus bar; and the connection portion 206 has a first preset angle with the correspondingly connected electrode finger.

[0101] In the embodiment of the present application, the preset angles mentioned, such as the first preset angle, and the second preset angle, the third preset angle, and the fourth preset angle mentioned below are all non-zero angles. Adjacent electrode fingers may be arranged in parallel, and the electrode fingers and the bus bar may be arranged vertically. The first direction may specifically refer to the length extension direction of the electrode fingers (such as Figure 2 The y direction in the resonator is shaped close to a rectangle, and the setting of the connection portion 206 can change the electric field distribution and the stress distribution of the lateral high-order mode, so that the coupling coefficient of the lateral high-order mode decreases or even becomes zero. Therefore, the lateral high-order mode can be greatly weakened without almost changing the shape of the resonator and without sacrificing the Q value of the resonator. In addition, the solution can also increase the static capacitance of the resonator without sacrificing the Q value, and adjust the electromechanical coupling coefficient of the resonator by setting a suitable angle and length of the bending area (such as the connection portion 206), thereby adjusting the bandwidth.

[0102] In the embodiment of the present application, the distance between adjacent first electrode fingers 203 and the distance between adjacent second electrode fingers 204 can be equal. Therefore, the electrode spacing of the elastic wave resonator can refer to the spacing between adjacent electrode fingers in the same bus bar, which can be denoted as λ. Specifically, the spacing between the centers of adjacent first electrode fingers 203 and the centers of second electrode fingers 204 is λ / 2, the spacing between the centers of adjacent first electrode fingers 203 is λ, and the spacing between the centers of adjacent second electrode fingers 204 is λ.

[0103] In the present application, please refer to Figure 3, the aperture region 209 is the region where the plurality of first electrode fingers 203 and the plurality of second electrode fingers 204 overlap; the air gap region 210 is the region between the free end of the second electrode finger 204 and the first bus bar 201, and the region between the free end of the first electrode finger 203 and the second bus bar 202. In other words, the aperture region 209 is the region where the plurality of electrode fingers overlap; the air gap region 210 is the region between the free end of the electrode finger and the bus bar on the opposite side of the electrode finger.

[0104] For a feasible implementation, please continue to refer to Figure 2 The length d of the connecting portion 206 along the first direction ranges from 0.05λ to 0.2L. In this embodiment, λ is the above-mentioned electrode spacing; L is the length of the aperture region 209 of the top electrode 2 along the first direction (the aperture region 209 along the first direction). Figure 3 The length in the y direction); the aperture region 209 is the region where the first electrode finger 203 and the second electrode finger 204 overlap. Usually, the electrode spacing and in-plane orientation of the bending region (specifically, the connecting portion 206 and the extension portion 207 described below) are different from those of the aperture region 209, and the bending region is too short to excite effective resonance. Therefore, the capacitance generated in the bending region will contribute to the total capacitance as redundant capacitance. The capacitance of the bending region is proportional to the length of the bending region, and due to the electromechanical coupling coefficient k2 = (π^2 / 8) × (Cm / C0), where Cm represents dynamic capacitance and C0 represents static capacitance. The bending region does not change Cm, but increases C0. The more C0 is increased, the smaller the electromechanical coupling coefficient. Therefore, the electromechanical coupling coefficient can be adjusted by adjusting the length of the bending region.

[0105] In a feasible implementation, there are at least (1 / 4)N electrode fingers in the top electrode 2, and the corresponding positions are provided with connecting portions 206; N is the total number of electrode fingers included in the top electrode 2, so as to achieve a better effect of suppressing lateral high-order modes. Optionally, these connecting portions 206 can be relatively evenly distributed in the entire interdigitated electrode 211, for example, the electrode fingers provided with connecting portions 206 can be spaced 3 to 4 electrode fingers apart, or 1 to 2 in some areas, 4 to 5 in some areas, etc., without limitation here, and it should be ensured that the connecting portions 206 in the top electrode 2 are generally evenly distributed overall.

[0106] For another possible implementation, please continue to refer to Figure 3 , the top electrode 2 also includes an extension 207; at least some of the electrode fingers in the top electrode 2 have an extension 207 at their ends; the extension 207 and the corresponding electrode finger have a third preset angle, and the extension 207 is located in the air gap region 210. This further improves the effect of suppressing the lateral high-order mode of the resonator. In the embodiment of the present application, the region where the extension 207 and the connection portion 206 are located can be collectively referred to as a bending region.

[0107] In another possible implementation, see Figure 4 The top electrode 2 also includes two reflective grids 3; a reflective grid 3 is provided on both sides of the interdigitated electrode 211. Optionally, each reflective grid 3 specifically includes a third bus bar 302, a fourth bus bar 303 and a plurality of reflective bars 301; the third bus bar 302 and the fourth bus bar are connected along the length direction of the electrode finger (specifically, it can be as follows Figure 2 The two reflective gratings 3 are arranged at intervals along the y direction shown in the figure, and a plurality of reflective strips 301 are arranged at intervals along the second direction, and one end of each reflective strip 301 is connected to the third bus bar 302, and the other end of the reflective strip 301 is connected to the fourth bus bar 303. Optionally, the two reflective gratings 3 can be in a centrally symmetrical structure. Optionally, the shapes of the reflective strips 301 in each reflective grating 3 can be the same or different, which is not limited here. Optionally, in order to further improve the suppression effect of the lateral high-order mode, a connecting portion 206 can also be provided between the reflective strip 301 and the connected bus bar, and the shape and size of the connecting portion 206 can be the same as those in the interdigitated electrode 211, which can also be different, which is not limited here.

[0108] In a feasible implementation, the material of the piezoelectric film 1 is lithium tantalate or lithium niobate.

[0109] In one possible implementation, see Figure 5 The elastic wave resonator further includes a bottom electrode 7; the bottom electrode 7 is located below the piezoelectric film 1. In a feasible embodiment, the bottom electrode 7 is a surface electrode. In another feasible embodiment, please refer to Figure 6 , the bottom electrode 7 is an interdigitated electrode 211; each electrode finger of the bottom electrode 7 corresponds to each electrode finger of the top electrode 2 one by one, and the misalignment distance between the electrode fingers in the bottom electrode 7 corresponding to the electrode fingers of the top electrode 2 does not exceed 20% of the width of the electrode fingers of the top electrode 2. Specifically, the interdigitated electrodes 211 of the top electrode 2 and the interdigitated electrodes 211 of the bottom electrode 7 can be the same, such as the width of the electrode fingers of the top electrode 2 is the same as the width of the electrode fingers of the bottom electrode 7, and the number is also the same. Optionally, the central axis of the corresponding electrode fingers in the top electrode 2 and the bottom electrode 7 can be coincident (such as Figure 6 The central axes of the two electrodes may also be misaligned by a certain distance, and optionally, the misalignment distance does not exceed 20% of the width of the electrode finger of the top electrode 2. Optionally, a reflective grid 3 may also be provided on both sides of the bottom electrode 7. The material of the top electrode 2 and the bottom electrode 7 is a conductive material; the conductive material includes one or more combinations of copper, aluminum, gold, silver, tungsten, platinum, nickel, chromium, molybdenum, titanium, graphene, copper-aluminum alloy, aluminum-silicon alloy, doped silicon, silicon carbide, and gallium nitride.

[0110] In one possible implementation, see Figure 7The elastic wave resonator also includes a dielectric layer 5; the dielectric is located below the piezoelectric film 1; optionally, the dielectric layer 5 is a single-layer material or a multi-layer material; the dielectric layer 5 includes one or more of silicon oxide, silicon nitride, polycrystalline silicon, amorphous silicon, aluminum oxide, and aluminum nitride, or the dielectric layer 5 is one or more of a temperature compensation layer, a heat dissipation layer, a trap-rich layer, a bonding layer, and a low sound velocity layer.

[0111] In one possible implementation, see Figure 8 The elastic wave resonator also includes a supporting substrate 4; the supporting substrate 4 is located below the piezoelectric film 1; optionally, the supporting substrate 4 includes one of various crystal forms of sapphire, silicon, spinel, silicon carbide, diamond, diamond-like carbon, silicon nitride, boron nitride, boron carbide, quartz, germanium, aluminum nitride, silicon nitride, yttrium aluminum garnet, lithium tantalate, and lithium niobate.

[0112] In a feasible embodiment, the supporting substrate 4 includes a stacked supporting structure and a high acoustic velocity layer; the high acoustic velocity layer is a material that is easy to form and process; the material of the supporting structure includes any one of quartz, silicon, sapphire, spinel, and yttrium aluminum garnet; the material of the high acoustic velocity layer includes any one of silicon carbide, diamond, diamond-like carbon, aluminum oxide, aluminum nitride, boron nitride, boron carbide and silicon nitride of different crystal forms and different cuts.

[0113] In one possible implementation, see Fig. 9 A Bragg reflection layer 6 is also provided between the piezoelectric film 1 and the supporting substrate 4 .

[0114] The above mainly illustrates the elastic wave resonator along the height direction of the elastic wave resonator (such as Figure 1 In the z direction as shown in the figure, the structure of each layer can be distributed in the viable solution, and in fact, it can also be a combination of the above-mentioned layer solutions. For example, when the elastic wave resonator is provided with a bottom electrode 7, a dielectric layer 5, a Bragg reflection layer 6, a support substrate 4, etc. can also be provided thereunder, that is, a top electrode 2+piezoelectric film 1+bottom electrode 7+support substrate 4 (such as Fig.10 Structure shown), or, top electrode 2+piezoelectric film 1+bottom electrode 7+dielectric layer 5+support substrate 4 (such as Fig.11 Alternatively, a top electrode 2+piezoelectric film 1+bottom electrode 7+Bragg reflection layer 6+support substrate 4 solution (such as Fig.12 Similarly, if the elastic wave resonator does not include the bottom electrode 7, a dielectric layer 5 and a supporting substrate 4 are provided below the bottom electrode 7, that is, a structure of a top electrode 2 + a piezoelectric film 1 + a dielectric layer 5 + a supporting substrate 4 can be formed, and the structure shown in FIG. Fig.13 The elastic wave resonator shown in FIG. 1 and FIG. 2 can also be formed as shown in FIG. 3 , because the dielectric layer 56 can be a multilayer material structure. Fig.14 The elastic wave resonator shown.

[0115] In addition to solutions with different layer structures, the embodiments of the present application can also be classified according to the structure of the top electrode 2, such as the shape of the busbar in the interdigital electrode 211, the shape, size, and number of the connecting portion 206, the shape, size, and number of the extending portion 207, the shape, size, and number of the dummy electrode 208, and the shape of the reflector 3, etc. This will be described in detail below.

[0116] A conventional structure, namely comparative example 1, is provided, which includes a piezoelectric film 1 and a top electrode 2 located on the piezoelectric film 1. The structure of the top electrode 2 can be as follows: Fig.15 The structure shown, i.e., including the interdigitated electrode 211 and a reflective structure on both sides, is mainly different from the structure of the present application in that the top electrode 2 is not provided with a connecting portion 206, i.e., no bending structure is provided.

[0117] Specifically, in the comparative example 1, the material of the piezoelectric film 11 is Y42-cut lithium tantalate with a thickness of 600 nm; the material of the top electrode 2 is aluminum with a thickness of 160 nm; λ is 2.0 μm; and the interdigitated electrode 211 includes 60 pairs of electrode fingers, and the reflective grating 32 includes 20 reflective strips 301. The target mode of the elastic wave resonator is the SH0 mode. Fig.16 From the admittance / conductance curve shown, it can be seen that there are very strong transverse high-order modes between the resonant frequency and the anti-resonant frequency of the main mode and near the anti-resonant frequency. These parasitic modes will cause fluctuations in the filter passband. Further, by comparing the vibration mode diagram corresponding to Example 1 (see Fig.17 ) It can be seen that the parasitic lateral high-order modes leak toward the bus bar area, which also leads to a lower Q value.

[0118] Another embodiment 1 is provided, and its structure can be as follows Figure 1 and Figure 3 In the elastic wave resonator shown in the figure, specifically, the material of the piezoelectric film 1 is Y42-cut lithium tantalate with a thickness of 600 nm; the material of the top electrode 2 is aluminum with a thickness of 160 nm; λ is 2.0 μm; and the interdigital electrode 211 includes 60 pairs of electrode fingers, and a reflection grating 3 is respectively provided on both sides of the interdigital electrode 211, and the reflection grating 3 can be specifically as follows Figure 4 In the structure shown in FIG. 1 , the reflector 3 includes 20 reflective strips 301, the length d of the connecting portion 206 is 0.25λ, and the angles between the extending portion 207, the connecting portion 206 and the extending direction (i.e., the first direction) of the electrode finger are all 70°. Fig.18 The admittance / conductance curve shown is compared with that of Comparative Example 1. Fig.16By comparison, it can be seen that the lateral high-order modes between the resonant frequency and the anti-resonant frequency, as well as near the anti-resonant frequency, have been greatly weakened. This is because the bending area (including the connecting portion 206 and the extension portion 207) causes a change in the electric field distribution, and the changes in the sound wave propagation direction, thickness-to-wavelength ratio, etc. in the bending area cause the sound velocity in this area to be lower than that in the aperture area 209 of the interdigital electrode 211, thus causing a change in the stress distribution of the lateral high-order mode. Therefore, by setting the bending area, the coupling coefficient of some lateral high-order modes can be greatly reduced, thereby achieving the purpose of suppression. Please refer to Fig.19 , which shows the Bode-Q curve comparison of Example 1 and Comparative Example 1. It can be seen that compared with Comparative Example 1, in Example 1, not only the parasitic mode is suppressed, the Bode-Q curve is smoother, and the Q value near the anti-resonance frequency is greatly improved. Further, through the vibration mode diagram corresponding to Comparative Example 1 (see Fig. 20 ) It can be seen that the lateral high-order modes are suppressed and the corresponding energy leakage is also significantly reduced.

[0119] In the present application, please refer to Figure 2 , it can be that each electrode finger is provided with a connection portion 206, and the first preset angle between the connection portion 206 and the first direction is equal. Optionally, the angles between each connection portion 206 in the top electrode 2 and the first direction may not be all equal, and the connection portion 206 may be provided only on some electrode fingers, which is not limited here. Please refer to Figure 3 , each electrode finger may be provided with an extension portion 207, and the angles between these extension portions 207 and the first direction may be equal, or not all equal, or the angles between the extension portions 207 on the same side (such as the side close to the first bus bar 201) and the first direction may be equal, and the angles between the extension portions 207 on the other side (such as the side close to the second bus bar 202) and the first direction may be equal, but the angles on both sides may be unequal. For the convenience of photolithography, the third preset angle between the extension portions 207 on the same side and the first direction may be equal to the first preset angle mentioned above. Optionally, all electrode fingers may be provided with a connection portion 206, and only some electrode fingers may be provided with an extension portion 207 (see Fig.21 ). Optional, see Fig. 22 Alternatively, the connecting portion 206 may be provided on some of the electrode fingers, the extending portion 207 may be provided on some of the electrode fingers, or the connecting portion 206 and the extending portion 207 may not be provided on one electrode finger at the same time. Fig.23, and a connection portion 206 and an extension portion 207 may be provided on each electrode finger, and the third preset angle is equal to the first preset angle. Optionally, when the top electrode 2 includes a reflector 3, a connection portion 206 may be provided at the connection between each reflective bar 301 and each bus bar, or a connection portion 206 may be provided only at the connection between one bus bar and all reflective bars 301, or a connection portion 206 may be provided at the connection between some reflective bars 301 and the bus bar, and the positions, quantities and shapes of the connection portions 206 provided in the two reflector gratings 3 may be different, and the shape, size and position (i.e., the angle with the first direction) of the connection portion 206 provided in the reflector grating 3 may also be different from those in the interdigitated electrode 211. The present application does not limit the specific number of the extension portions 207 and the connection portions 206 and the angles between the corresponding electrode fingers.

[0120] In another possible implementation, see Fig.24 , the top electrode 2 also includes a dummy electrode 208; a dummy electrode 208 is provided between the ends of at least some of the electrode fingers in the top electrode 2 and the bus bar on the opposite side. Optionally, the ends of all electrode fingers may be provided with dummy electrodes 208, or the ends of some electrode fingers may be provided with dummy electrodes 208. In a feasible implementation, the angles between the dummy electrodes 208 in the top electrode 2 and the first direction are not all equal. Optionally, the angles between the dummy electrodes 208 in the top electrode 2 and the first direction may also all be equal.

[0121] Another embodiment 2 is provided. The top electrode 2 in the embodiment 2 is as follows Fig.24 The structure shown in the figure, specifically, embodiment 2 includes a piezoelectric film 1 and a top electrode 2 thereon, the material of the piezoelectric film 1 is Y42-cut lithium tantalate, with a thickness of 600nm; the material of the top electrode 2 is aluminum, with a thickness of 160nm; λ is 2.0μm; and the interdigitated electrode 211 includes 60 pairs of electrode fingers, the reflective grid 32 includes 20 reflective strips 301, the length d of the bending region is 0.25λ, the angles between the extension portion 207 and the connection portion 206 and the first direction are both 70°, and the length of the dummy electrode 208 is λ. Subsequent relevant calculations can be performed to obtain the following: Fig.25 The admittance / conductance curve shown in the figure shows that it has a good suppression effect on the lateral high-order mode. Fig.26 , which shows a comparison of the Bode-Q curves of Example 1 and Example 2. It can be seen that, compared with Example 1, the Q value of Example 2 near the anti-resonance frequency is further improved. This is because the pseudo-finger electrode 208 prevents the leakage of sound waves to the bus bar area.

[0122] In another possible implementation, see Fig. 27 , the acoustic wave propagation direction of the elastic wave resonator (i.e. Fig. 27The second direction in the plane of the piezoelectric film 1) and the axis where the in-plane sound velocity of the piezoelectric film 1 takes an extreme value (i.e. Fig. 27 The third direction in the second direction does not overlap, that is, the second direction and the third direction have a non-zero angle, and the third direction can specifically refer to Fig. 27 Optionally, the acoustic wave propagation direction of the elastic wave resonator may be consistent with the axis where the in-plane acoustic velocity of the piezoelectric film 1 takes an extreme value, as described above. Figures 21 to 24 The structure shown.

[0123] In another possible implementation, see Fig.28 , the angles between the connecting portion 206 and the extending portion 207 provided on the electrode finger and the first direction are different.

[0124] Another embodiment 3 is provided. The top electrode 2 in the embodiment 3 is as follows Fig.28 The structure shown in the figure, specifically, embodiment 3 includes a piezoelectric film 1 and a top electrode 2 thereon, the material of the piezoelectric film 1 is Y42-cut lithium tantalate, with a thickness of 600nm; the material of the top electrode 2 is aluminum, with a thickness of 160nm; λ is 2.0μm; and the interdigitated electrode 211 includes 60 pairs of electrode fingers, the reflective grid 32 includes 20 reflective strips 301, the length d of the bending region is 0.25λ, the angles between the upper extension 207 and the connecting portion 206 and the first direction are both 70°, the angles between the lower extension 207 and the connecting portion 206 and the first direction are both 72°, and the length of the pseudo-finger electrode 208 is λ. Subsequent relevant calculations can be performed to obtain the following: Fig.29 The admittance / conductance curve shown is compared with Example 2 (see Fig.25 ), the transverse high-order modes near the antiresonance are further suppressed, and the conductivity curve is smoother. Fig.30 , which shows a comparison diagram of the Bode-Q curves of Example 2 and Example 3. It can be seen that compared with Example 2, Example 3 is smoother near the anti-resonance and the Q value is also improved.

[0125] By setting the angles between the connecting portion 206 and the extension portion 207 connecting the upper and lower electrode fingers and the first direction to be different, the forked electrode 211 forms an asymmetric structure. Since the vibration of the main mode of the elastic wave resonator is concentrated in the aperture area 209, the higher the order of the lateral high-order mode, the more energy is distributed in the connecting portion 206, the extension portion 207 and the air gap area 210. At this time, the asymmetric connecting portion 206 and the extension portion 207 are conducive to destroying the resonance of the higher-order lateral high-order mode, thereby achieving the purpose of further suppression. The higher-order lateral high-order mode usually appears near the anti-resonance frequency. Therefore, Fig.30 The conductance curve near the mid-antiresonance frequency is smoother.

[0126] In another possible implementation, see Fig.31 The connecting portion 206 includes at least two sub-connecting segments 2061, and there is a second preset angle between adjacent sub-connecting segments 2061, and both of them have a non-zero angle with the first direction. Fig.32 When the top electrode 2 is provided with a dummy electrode 208, the dummy electrode 208 may not be perpendicular to the bus bar. Specifically, the dummy electrode 208 may be parallel to the sub-connection section 2061 closest to the bus bar. In fact, there is no restriction on whether the deflection angles of the dummy electrode 208 and the sub-connection portion 206 relative to the first direction are consistent, as long as the lateral high-order mode can be suppressed. However, if molding processing is taken into consideration, setting the angles of the dummy electrode 208, the connection portion 206 and the extension portion 207 with the first direction to be consistent is more convenient for molding processing.

[0127] In another possible implementation, see Fig.33 The extension portion 207 includes at least two sub-extension segments 2071, a fourth preset angle exists between adjacent sub-extension segments 2071, and both have a non-zero angle with the first direction. For example, the extension portion 207 may include two sub-extension segments 2071, and the connection portion 206 includes two sub-connection portions 2061.

[0128] Another embodiment 4 is provided. The top electrode 2 in the embodiment 4 is as follows Fig.33 The structure shown in the figure, specifically, embodiment 4 includes a piezoelectric film 1 and a top electrode 2 thereon, the material of the piezoelectric film 1 is Y42-cut lithium tantalate, with a thickness of 600nm; the material of the top electrode 2 is aluminum, with a thickness of 160nm; λ is 2.0μm; and the interdigitated electrode 211 includes 60 pairs of electrode fingers, the reflective grid 32 includes 20 reflective strips 301, the length d of the bending region is 0.6λ, the angle between each sub-extension segment 2071 and the sub-connection segment 2061 and the first direction is 70°, and the length of the pseudo-finger electrode 208 is λ. Subsequent relevant calculations can be performed to obtain the following: Fig.34 The admittance / conductance curve shown is compared with that of Comparative Example 1 (see Fig.16 ), the lateral high-order modes are greatly weakened. Fig.35 , which shows a Bode-Q curve comparison diagram of Example 4. It can be seen that compared with Example 2, Example 3 has a further improved Q value. In addition, the electromechanical coupling coefficient of Comparative Example 1 is 12.4%, the electromechanical coupling coefficient of Example 2 is 11.2%, and the electromechanical coupling coefficient of Example 4 is 10.1%. Therefore, by setting the length of the bending area and the degree of bending, the electromechanical coupling coefficient can be regulated, thereby achieving the regulation of the filter bandwidth, and in this process, the Q value of the resonator does not decrease, and the area does not increase significantly.

[0129] In another possible implementation, see Fig.36, the angles between each sub-connecting segment 2061 or sub-extending segment 2071 and the first direction may be different.

[0130] In another possible implementation, see Fig.37 The connecting portion 206 may include more than two sub-connecting segments 2061, and the extending portion 207 may also include more than two sub-extension segments 2071, that is, the specific number of sub-connecting segments 2061 and sub-extension segments 2071 is not limited herein.

[0131] In another possible implementation, see Fig.38 , the air gap region 210 includes a first region 2101, a second region 2102 and a third region 2103 which are sequentially connected and distributed along the second direction; the second region 2102 is provided with a dummy electrode 208 and a bridge 205; the third region 2103 is provided between one end of the dummy electrode 208 and the adjacent bus bar; the first region 2101 is provided between the other end of the dummy electrode 208 and the end of the extension 207 of the target first electrode finger 203 and / or the target second electrode finger 204; one end of the bridge 205 is connected to one end of the dummy electrode 208, and the other end of the bridge 205 is connected to the connection portion 206 of the target second electrode finger 204 and / or the target first electrode finger 203; the target second electrode finger 204 is adjacent to the target first electrode finger 203. Optionally, in the case where the extension 207 is not provided at the end of the target electrode finger, the first region 2101 may also be provided between the other end of the dummy electrode 208 and the end of the target first electrode finger 203. Optional, see Fig.39 , the bridge 205 may also penetrate the dummy electrode 208 and be connected to the connecting portion 206 of another adjacent electrode finger. Optionally, if the target first electrode finger 203 or the target second electrode finger 204 is not provided with the connecting portion 206, the bridge 205 may also be connected to the target first electrode finger 203 and / or the target second electrode finger 204. For example, for Fig.38 In the middle top electrode 2, all electrode fingers are provided with a connecting portion 206 and an extending portion 207. For the dummy electrode 208 arranged on the upper side of the top electrode 2, it is close to the first bus bar 201, so one end of the dummy electrode 208 is provided with a first area 2101 at the end of the extending portion 207 of the target second electrode finger 204, and the other end of the connector is connected to the connecting portion 206 of the target first electrode finger 203; for the dummy electrode 208 arranged on the lower side of the top electrode 2, it is close to the second bus bar 202, so one end of the dummy electrode 208 is provided with a first area 2101 at the end of the extending portion 207 of the target first electrode finger 203, and the other end of the connector is connected to the connecting portion 206 of the target second electrode finger 204.

[0132] In another possible implementation, see Fig.40By designing the shape of the bus bar, the lengths of the pseudo-finger electrodes 208 in the interdigitated electrodes 211 can be made different.

[0133] In a feasible embodiment, the shape of the connecting portion 206 includes a straight line (such as Fig.28 Shape shown), broken line shape (such as Fig.36 Shapes shown) and arcs (such as Fig.41 The shape of the extension portion 207 includes a straight line shape (such as Fig.28 Shape shown), broken line shape (such as Fig.36 Shapes shown) and arcs (such as Fig.41 The shape of the pseudo-finger electrode 208 includes any one of a straight line shape, a folded line shape and an arc shape or a combination of two. When the connecting portion 206 and the extending portion 207 are straight lines or folded lines, the angle between them and the first direction can range from 0 to 85 degrees to achieve better suppression of lateral high-order modes.

[0134] On the other hand, the present application further discloses a communication device, which includes the elastic wave resonator mentioned above; the communication device includes at least one of a filter, a duplexer and a multiplexer.

[0135] The above description is only an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. An elastic wave resonator, characterized in that: At least: Piezoelectric film; and a top electrode located on the piezoelectric film; The top electrode is an interdigitated electrode; The interdigitated electrodes include a first bus bar and a second bus bar spaced apart along a first direction, and first electrode fingers and second electrode fingers staggered along a second direction; the first electrode fingers are connected to the first bus bar, and the second electrode fingers are connected to the second bus bar; the second direction is the sound wave propagation direction of the elastic wave resonator, and is perpendicular to the first direction; Wherein, a connection portion is provided at a connection point between some electrode fingers in the top electrode and an adjacent bus bar; and a first preset angle exists between the connection portion and the correspondingly connected electrode finger.

2. The elastic wave resonator according to claim 1, characterized in that: The connecting portion is provided at the corresponding position of at least (1 / 4)N electrode fingers in the top electrode; N is the total number of electrode fingers included in the top electrode.

3. The elastic wave resonator according to claim 1, characterized in that: The angles between the connecting portions in the top electrode and the first direction are not all equal.

4. The elastic wave resonator according to claim 1, characterized in that: The connecting portion includes at least two sub-connecting segments, and a second preset angle exists between adjacent sub-connecting segments.

5. The elastic wave resonator according to claim 1, characterized in that: The length of the connecting portion along the first direction ranges from 0.05λ to 0.2L; λ is the distance between the centers of adjacent electrode fingers on the same bus bar; L is the length of the aperture area of ​​the top electrode along the first direction; the aperture area is the area where the first electrode finger and the second electrode finger overlap.

6. The elastic wave resonator according to claim 1, characterized in that: The top electrode further includes an extension portion; The extension portion is disposed at the end of at least some of the electrode fingers in the top electrode; and a third preset angle exists between the extension portion and the corresponding electrode finger.

7. The elastic wave resonator according to claim 6, characterized in that: The included angles between the extension portions of the top electrode and the first direction are not all equal.

8. The elastic wave resonator according to claim 6, characterized in that: The extension portion includes at least two sub-extension segments, and a fourth preset angle exists between adjacent sub-extension segments.

9. The elastic wave resonator according to claim 6, characterized in that: In the top electrode, the angles between the extension portions and the first direction are all equal, and the angles between the connection portions and the first direction are all equal.

10. The elastic wave resonator according to claim 6, characterized in that: The shape of the connecting portion includes any one of a straight line shape, a broken line shape and an arc shape, or a combination of two; The shape of the extension portion includes any one of a straight line shape, a broken line shape and an arc shape, or a combination of two of the two.

11. The elastic wave resonator according to claim 1, characterized in that: The top electrode also includes a dummy finger electrode; The dummy finger electrode is arranged between the end of at least part of the electrode fingers in the top electrode and the bus bar on the opposite side.

12. The elastic wave resonator according to claim 11, characterized in that The included angles between the pseudo-finger electrodes in the top electrode and the first direction are not all equal.

13. The elastic wave resonator according to claim 1, characterized in that: The propagation direction of the sound wave does not coincide with the axis at which the in-plane sound velocity of the piezoelectric film takes an extreme value.

14. The elastic wave resonator according to claim 1, characterized in that The extension portion is located in an air gap region; the air gap region is a region between a free end of the electrode finger and a bus bar on an opposite side of the electrode finger; The air gap area includes a first area, a second area and a third area which are distributed and connected in sequence along the second direction; The second area is provided with a dummy electrode and a bridge member; A third region is provided between one end of the dummy electrode and an adjacent bus bar; The first region is provided between the other end of the dummy electrode and the end of the target first electrode finger or the end of the extension portion of the target first electrode finger; One end of the bridge is connected to one end of the dummy electrode, and the other end of the bridge is connected to a target second electrode finger; the target second electrode finger is a second electrode finger adjacent to the target first electrode finger.

15. The elastic wave resonator according to claim 1, characterized in that The top electrode also includes two reflective grids; A reflection grid is respectively provided on both sides of the interdigital electrode.

16. The elastic wave resonator according to claim 1, characterized in that Also included is a bottom electrode; The bottom electrode is located below the piezoelectric film.

17. The elastic wave resonator according to claim 16, characterized in that: The bottom electrode is a surface electrode; or, The bottom electrode is a forked electrode; each electrode finger of the bottom electrode corresponds to each electrode finger of the top electrode one by one, and the misalignment distance between the electrode fingers in the bottom electrode corresponding to the electrode fingers of the top electrode does not exceed 20% of the width of the electrode fingers of the top electrode.

18. The elastic wave resonator according to claim 1, wherein: Also includes a dielectric layer; The medium is located below the piezoelectric film; The dielectric layer is a single-layer material or a multi-layer material; The dielectric layer includes one or more of silicon oxide, silicon nitride, polysilicon, amorphous silicon, aluminum oxide, and aluminum nitride, or the dielectric layer is one or more of a temperature compensation layer, a heat dissipation layer, a trap-rich layer, a bonding layer, and a low acoustic velocity layer.

19. The elastic wave resonator according to claim 1, characterized in that Also included is a supporting substrate; The supporting substrate is located below the piezoelectric film; The support substrate includes one of sapphire, silicon, spinel, silicon carbide, diamond, diamond-like carbon, silicon nitride, boron nitride, boron carbide, quartz, germanium, aluminum nitride, silicon nitride, yttrium aluminum garnet, lithium tantalate, and lithium niobate in various crystal forms.

20. The elastic wave resonator according to claim 19, characterized in that The support substrate comprises a stacked support structure and a high acoustic velocity layer; The high sound velocity layer is made of a material that is easy to shape and process; The material of the support structure includes any one of quartz, silicon, sapphire, spinel, and yttrium aluminum garnet; The material of the high acoustic velocity layer includes any one of silicon carbide, diamond, diamond-like carbon, aluminum oxide, aluminum nitride, boron nitride, boron carbide and silicon nitride in different crystal forms and different cut shapes.

21. The elastic wave resonator according to claim 19, characterized in that A Bragg reflection layer is also provided between the piezoelectric film and the supporting substrate.

22. The elastic wave resonator according to claim 1, characterized in that The material of the top electrode is a conductive material; The conductive material includes one or more combinations of copper, aluminum, gold, silver, tungsten, platinum, nickel, chromium, molybdenum, titanium, graphene, copper-aluminum alloy, aluminum-silicon alloy, doped silicon, silicon carbide, and gallium nitride.

23. A communication device, characterized in that: comprising an elastic wave resonator as claimed in any one of claims 1 to 22; The communication device includes at least one of a filter, a duplexer and a multiplexer.

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