High-frequency acoustic resonator and communication device using same

Abstract

The invention relates to the technical field of microelectronic devices, in particular to a high-frequency acoustic resonator and a communication device applying the same. The high-frequency acoustic wave resonator comprises a supporting substrate, a bottom electrode, a piezoelectric layer and an interdigital transducer which are sequentially arranged from bottom to top; the corresponding distances of any two groups of interdigital electrodes in the interdigital transducer are equal; the distance corresponding to each group of interdigital electrodes is the distance between the centers of two adjacent interdigital electrodes in the interdigital transducer; the target mode of the high-frequency acoustic wave resonator is a high-order acoustic wave mode excited by a longitudinal electric field; the product of the period of the interdigital transducer and the resonant frequency of the target mode is smaller than the sound velocity of the supporting substrate; the period of the interdigital transducer is twice the distance corresponding to the interdigital electrode; two sides of the interdigital transducer are respectively provided with an energy processing device; and the energy processing device is used for scattering, transmitting or absorbing the zero-order mode. Therefore, on the premise that the target mode is not influenced, the Q value of the zero-order mode is reduced to the greatest extent, and the influence of related spurious passbands is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of microelectronic devices, and in particular to a high-frequency acoustic wave resonator and a communication device using the same. Background Art

[0002] With the development of 5G wireless communication systems, the newly added frequency bands have the characteristics of higher frequency and larger bandwidth, which puts higher requirements on the electromechanical coupling coefficient and resonant frequency of the resonator. The resonant frequency of the Bulk Acoustic Wave (BAW) resonator is inversely proportional to the thickness of the piezoelectric film. Its resonant frequency can be increased by reducing the thickness of the piezoelectric film. However, BAW devices require cavities or Bragg reflection layers to effectively confine the sound waves. As the frequency increases, the cavity structure poses challenges to the stability and heat dissipation characteristics of the device, while the Bragg reflection layer introduces complex processes and parasitic effects.

[0003] Surface acoustic wave (SAW) resonators based on piezoelectric heterogeneous substrates have great advantages in Q value, volume, temperature stability and power capacity. High-order acoustic wave modes excited by longitudinal electric fields based on high-acoustic-velocity support substrates can achieve higher frequencies than zero-order modes. However, multiple non-zero piezoelectric coefficient components in piezoelectric materials will lead to the generation of parasitic modes (such as zero-order Rayleigh mode, SH0 mode and LL-SAW mode), which will lead to a significant decrease in the out-of-band suppression level of the filter. Therefore, suppressing spurious modes other than the target mode is the key to achieving high-performance high-frequency and large-bandwidth filters. Summary of the invention

[0004] To solve the above technical problems, in one aspect, an embodiment of the present application provides a high-frequency acoustic wave resonator, which includes a supporting substrate, a bottom electrode, a piezoelectric layer and an interdigital transducer arranged in sequence from bottom to top;

[0005] The distances corresponding to any two groups of interdigital electrodes in the interdigital transducer are equal; the distance corresponding to each group of interdigital electrodes is the distance between the centers of two adjacent interdigital electrodes in the interdigital transducer; the target mode of the high-frequency acoustic wave resonator is a high-order acoustic wave mode excited by a longitudinal electric field; the product of the period of the interdigital transducer and the resonant frequency of the target mode is less than the acoustic velocity of the supporting substrate; the period of the interdigital transducer is twice the distance corresponding to the interdigital electrodes;

[0006] The interdigital transducer comprises a first side and a second side arranged along a first direction; the first direction is the width direction of the interdigital electrode; an energy processing device is respectively arranged on the first side and the second side; the energy processing device is used to scatter, transmit or absorb the zero-order mode.

[0007] In an exemplary embodiment, the energy processing device is used to transmit the zero-order mode;

[0008] The energy processing device is a first reflector;

[0009] The distance between the centers of adjacent electrodes in the first reflective grid is not equal to the distance corresponding to the interdigital electrodes;

[0010] At least one of the material of the first reflective grating, the duty cycle of the first reflective grating, the thickness of the first reflective grating, the material of the target layer corresponding to the area of ​​the first reflective grating, and the thickness of the target layer corresponding to the area of ​​the first reflective grating is different from the corresponding area of ​​the interdigital transducer; the target layer includes at least one of a bottom electrode, a piezoelectric layer and a supporting substrate.

[0011] In an exemplary embodiment, the energy processing device is used to absorb the zero-order mode;

[0012] The energy processing device includes a high damping layer;

[0013] The high damping layer includes a polymer material or a damaged layer; the damaged layer is formed by implanting ions into the piezoelectric film.

[0014] In an exemplary embodiment, the energy processing device is used to scatter the zero-order mode;

[0015] The energy handling device includes a load structure, a region of the piezoelectric layer having a through hole, or a region of the bottom electrode having an irregular shape.

[0016] In an exemplary embodiment, a second reflection grating is further provided between the first reflection grating and the interdigital transducer;

[0017] The distance between the centers of adjacent electrodes in the second reflector is equal to the distance corresponding to the interdigital electrodes;

[0018] The second reflector includes no more than 5 electrodes.

[0019] In an exemplary embodiment, a distance between centers of adjacent electrodes in the first reflection grid located on the first side is not equal to a distance between centers of adjacent electrodes in the first reflection grid located on the second side.

[0020] In an exemplary embodiment, a load layer is disposed on the first reflective grating, and / or the two first reflective gratings are of a symmetrical structure or an anti-symmetrical structure.

[0021] In an exemplary embodiment, the energy processing device is used to transmit the zero-order mode;

[0022] The energy processing device includes a region of the piezoelectric layer having a groove structure on its surface.

[0023] In an exemplary embodiment, the distance between the centers of adjacent electrodes in the first reflection grid has different values ​​at different positions in the first direction or the second direction; the second direction is the extension direction of the interdigital electrodes of the IDT.

[0024] In an exemplary embodiment, the bottom electrode and the IDT have no overlapping portion in the ineffective resonance region, or the region of the piezoelectric layer corresponding to the overlapping portion of the bottom electrode and the IDT in the ineffective resonance region is replaced by a dielectric region.

[0025] In an exemplary embodiment, the target mode is one of a high-order Lamb wave and a high-order horizontal shear wave.

[0026] On the other hand, an embodiment of the present application provides a high-frequency acoustic wave resonator, which is formed by cascading at least two of the above-mentioned high-frequency acoustic wave resonators.

[0027] In another aspect, an embodiment of the present application provides a communication device, which includes the above-mentioned acoustic wave resonator;

[0028] The communication device includes at least one of a filter, a duplexer, and a multiplexer.

[0029] By adopting the above technical solution, the high-frequency acoustic wave resonator provided by the present application has the following beneficial effects:

[0030] The high-frequency acoustic wave resonator provided by the present application includes a supporting substrate, a bottom electrode, a piezoelectric layer and an interdigital transducer arranged in sequence from bottom to top; the distances corresponding to any two groups of interdigital electrodes in the interdigital transducer are equal; the distance corresponding to each group of interdigital electrodes is the distance between the centers of two adjacent interdigital electrodes in the interdigital transducer; the target mode of the high-frequency acoustic wave resonator is a high-order acoustic wave mode excited by a longitudinal electric field; the product of the period of the interdigital transducer and the resonant frequency of the target mode is less than the speed of sound of the supporting substrate; the period of the interdigital transducer is twice the distance corresponding to the interdigital electrodes; the interdigital transducer includes a first side and a second side arranged along a first direction; the first direction is the width direction of the interdigital electrodes; an energy processing device is respectively provided on the first side and the second side; the energy processing device is used to scatter, transmit or absorb the zero-order mode. In this way, the Q value of the zero-order mode can be minimized without affecting the target mode, and the influence of the related stray passband can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] 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.

[0032] Figure 1 It is a structural schematic diagram of an existing acoustic wave resonator provided in an embodiment of the present application;

[0033] Figure 2 is a cross-sectional view of a first resonator provided in an embodiment of the present application;

[0034] Figure 3 is a cross-sectional view of a second resonator provided in an embodiment of the present application;

[0035] Figure 4 is a cross-sectional view of a third resonator provided in an embodiment of the present application;

[0036] Figure 5 is a cross-sectional view of a fourth resonator provided in an embodiment of the present application;

[0037] Figure 6 is a cross-sectional view of a fifth resonator provided in an embodiment of the present application;

[0038] Figure 7 is a cross-sectional view of a sixth resonator provided in an embodiment of the present application;

[0039] Figure 8 is a cross-sectional view of a seventh resonator provided in an embodiment of the present application;

[0040] Fig. 9 is a cross-sectional view of an eighth resonator provided in an embodiment of the present application;

[0041] Fig.10 is a cross-sectional view of a ninth resonator provided in an embodiment of the present application;

[0042] Fig.11 is a cross-sectional view of a tenth resonator provided in an embodiment of the present application;

[0043] Fig.12 is a cross-sectional view of an eleventh resonator provided in an embodiment of the present application;

[0044] Fig.13 is a top view of an eleventh resonator provided in an embodiment of the present application;

[0045] Fig.14 is a top view of a twelfth resonator provided in an embodiment of the present application;

[0046] Fig.15 is a top view of a thirteenth resonator provided in an embodiment of the present application;

[0047] Fig.16 is a top view of a fourteenth resonator provided in an embodiment of the present application;

[0048] Fig.17is a top view of a fifteenth resonator provided in an embodiment of the present application;

[0049] Fig.18 It is a structural schematic diagram of a comparative example 1 provided in the embodiments of the present application;

[0050] Fig.19 is an admittance curve of a comparative example 1 provided in an embodiment of the present application;

[0051] Fig. 20 This is a method provided by the embodiment of the present application. Fig.18 The simulated admittance curves corresponding to different numbers of interdigitated electrode groups of the structure shown;

[0052] Fig.21 This is a method provided by the embodiment of the present application. Figure 4 A portion of the simulated admittance curves corresponding to different P2 in the structure shown;

[0053] Fig. 22 This is a method provided by the embodiment of the present application. Figure 4 Another part of the simulated admittance curve corresponding to different P2 in the structure shown;

[0054] Fig.23 This is a method provided by the embodiment of the present application. Fig.21 and Fig. 22 Admittance ratio curve of zero-order mode at different P2 / P1;

[0055] Fig.24 is an admittance curve provided in an embodiment of the present application when P2 is 0.95P1 and P1 respectively;

[0056] Fig.25 This is a method provided by the embodiment of the present application. Fig.24 The corresponding vibration mode diagram of SH1 mode at the anti-resonance frequency point when P2 is equal to P1;

[0057] Fig.26 This is a method provided by the embodiment of the present application. Fig.24 The corresponding vibration mode diagram of SH1 mode at the anti-resonance frequency point when P2 equals 0.95P1;

[0058] Fig. 27 This is a method provided by the embodiment of the present application. Fig.24 The corresponding vibration mode diagram of the zero-order Rayleigh mode at the anti-resonance frequency point when P2 is equal to P1;

[0059] Fig.28 This is a method provided by the embodiment of the present application. Fig.24 The corresponding vibration mode diagram of the zero-order Rayleigh mode at the anti-resonance frequency point when P2 equals 0.95P1;

[0060] Fig.29 This is a method provided by the embodiment of the present application. Fig.24 The corresponding vibration mode diagram of SH0 mode at the anti-resonance frequency point when P2 is equal to P1;

[0061] Fig.30 This is a method provided by the embodiment of the present application. Fig.24 The corresponding vibration mode diagram of SH0 mode at the anti-resonance frequency point when P2 equals 0.95P1;

[0062] Fig.31 This is a method provided by the embodiment of the present application. Fig.24 The vibration mode diagram of the corresponding LL-SAW mode at the anti-resonance frequency point when P2 is equal to P1;

[0063] Fig.32 This is a method provided by the embodiment of the present application. Fig.24 The vibration mode diagram of the corresponding LL-SAW mode at the anti-resonance frequency point when P2 equals 0.95P1;

[0064] Fig.33 The number of electrodes of the first reflective grid provided in the embodiment of the present application corresponds to Fig.18 Simulated admittance curve of the structure shown;

[0065] Fig.34 This is a method provided by the embodiment of the present application. Fig.33 Admittance ratio curves corresponding to different numbers of electrodes of the first reflector;

[0066] Fig.35 is an admittance curve provided in an embodiment of the present application when P2 is 0.9P1 and P1 respectively;

[0067] Fig.36 is an admittance curve corresponding to when P2 is P1 and when there is no first reflection grating, provided in an embodiment of the present application;

[0068] Fig.37 is a cross-sectional view of a sixteenth resonator provided in an embodiment of the present application;

[0069] Fig.38 This is a method provided by the embodiment of the present application. Figure 4 The simulated admittance curves corresponding to different groups of interdigital electrodes when there is no reflective grating in the structure shown;

[0070] Fig.39 This is a method provided by the embodiment of the present application. Fig.37 The simulated admittance curves corresponding to different groups of interdigital electrodes;

[0071] Fig.40 This is a method provided by the embodiment of the present application. Fig.38 and Fig.39 The admittance ratio curves corresponding to different groups of interdigitated electrodes;

[0072] Fig.41 When the number of groups of interdigital electrodes provided in the embodiment of the present application is 20 groups Fig.37 The simulated admittance curves corresponding to the presence or absence of energy absorption devices;

[0073] Fig.42 is a cross-sectional view of a seventeenth resonator provided in an embodiment of the present application;

[0074] Fig.43 is a cross-sectional view of an eighteenth resonator provided in an embodiment of the present application;

[0075] Fig.44 is a cross-sectional view of a nineteenth resonator provided in an embodiment of the present application;

[0076] Fig.45 is a cross-sectional view of the twentieth resonator provided in an embodiment of the present application;

[0077] Fig.46 is a top view of a twenty-first resonator provided in an embodiment of the present application;

[0078] Fig.47 is a top view of the twenty-second resonator provided in an embodiment of the present application;

[0079] Fig.48 It is a top view of the twenty-third resonator provided in the embodiment of the present application.

[0080] The following is a supplementary description of the attached drawings:

[0081] 1-support substrate; 2-bottom electrode; 3-piezoelectric layer; 301-groove structure; 4-interdigital transducer; 401-first bus bar; 402-second bus bar; 403-interdigital electrode; 5-energy processing device; 6-dielectric layer; 7-second reflection grid; 8-high damping layer; 9-load layer; 10-through hole; 11-dielectric area; 12-load structure; 13-first reflection grid. DETAILED DESCRIPTION

[0082] 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.

[0083] 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.

[0084] 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.

[0085] One structure of the existing high-order acoustic wave mode resonator is to include a high-acoustic-velocity support substrate, a bottom electrode, a piezoelectric layer and an interdigital transducer stacked in sequence (see Figure 1 ), which is constrained by a high-acoustic-velocity support substrate. The structure utilizes the high-order acoustic wave mode excited by the longitudinal electric field to achieve high frequency and large electromechanical coupling coefficient. The simultaneous existence of the transverse and longitudinal electric fields and the presence of multiple non-zero piezoelectric coefficient components in the piezoelectric material lead to the generation of parasitic modes. In order to reduce or eliminate parasitic modes, those skilled in the art have proposed to design a series-parallel resonator so that a certain parasitic response in the series-parallel resonator overlaps, thereby reducing or even eliminating the influence of the corresponding parasitic mode in the filter response. However, this solution is only applicable to the case of a single parasitic mode. When there are many parasitic modes, it is difficult to simultaneously achieve frequency overlap of multiple parasitic modes in the series-parallel resonator.

[0086] To this end, by targeting the shortcomings of the above-mentioned existing solutions, the present application proposes a new high-frequency acoustic wave resonator, which includes a supporting substrate, a bottom electrode, a piezoelectric layer and an interdigital transducer arranged in sequence from bottom to top, and an energy processing device located on both sides of the interdigital transducer for scattering, transmitting or absorbing the zero-order mode. Unlike the above-mentioned two existing solutions, the energy processing device can achieve scattering, transmission or absorption of the zero-order mode through the energy processing device, thereby minimizing the Q value of the zero-order mode and reducing the influence of related stray passbands. Since the propagation component of the target mode in the horizontal direction is small, the zero-order mode is the opposite, so that the scheme can reduce the admittance ratio of multiple zero-order modes at the same time without affecting the target mode. The structure is very simple and stable, and is generally applicable to high-order acoustic wave devices. Therefore, it has the potential to be applied to high-performance high-frequency and large-bandwidth filters.

[0087] See also Figure 2 , Figure 2 It is a cross-sectional view of the first resonator provided by the embodiment of the present application. The high-frequency acoustic wave resonator includes a supporting substrate 1, a bottom electrode 2, a piezoelectric layer 3 and an interdigital transducer 4 arranged in sequence from bottom to top; the distances corresponding to any two groups of interdigital electrodes 403 in the interdigital transducer 4 are equal; the distance corresponding to each group of interdigital electrodes 403 is the distance P1 between the centers of two adjacent interdigital electrodes 403 in the interdigital transducer 4; the target mode of the high-frequency acoustic wave resonator is a high-order acoustic wave mode excited by a longitudinal electric field; the product of the period of the interdigital transducer 4 and the resonant frequency of the target mode is less than the sound velocity of the supporting substrate 1; the period of the interdigital transducer 4 is twice the distance P1 corresponding to the interdigital electrodes 403; the interdigital transducer 4 includes a first side and a second side arranged along a first direction; the first direction is the width direction of the interdigital electrodes 403; an energy processing device 5 is respectively provided on the first side and the second side; the energy processing device 5 is used to scatter, transmit or absorb the zero-order mode. Therefore, the Q value of the zero-order mode can be minimized without affecting the target mode, thereby reducing the impact of related spurious passbands.

[0088] In an exemplary embodiment, the target mode is one of a high-order Lamb wave and a high-order horizontal shear wave. The parasitic mode is a zero-order mode, which may include a zero-order Rayleigh mode, a zero-order horizontal shear mode (Fundamental shearhorizontal mode, SH0) mode, and a longitudinal leakage surface acoustic wave (Longitudinal Leaky Surface Acoustic Wave, LL-SAW) mode.

[0089] In the embodiment of the present disclosure, the material of the piezoelectric layer 3 can be one of lithium tantalate, lithium niobate, lead zirconate titanate or lead magnesium niobate-lead titanate; Figure 3A dielectric layer 6 is provided between the support substrate 1 and the bottom electrode 2. The dielectric layer 6 may be a single layer or a multilayer. The material of the dielectric layer 6 includes but is not limited to silicon oxide, silicon nitride, aluminum nitride, polycrystalline silicon, and aluminum oxide. Optionally, the support substrate 1 is one of silicon carbide, diamond, diamond-like carbon, sapphire, aluminum nitride, boron nitride, boron carbide, and silicon nitride of different crystal forms and different cuts. Optionally, the support substrate 1 includes a stacked substrate and a high acoustic velocity layer; the substrate is one of quartz, silicon, and sapphire; the material of the high acoustic velocity layer is one of silicon carbide, diamond, diamond-like carbon, aluminum oxide, aluminum nitride, boron nitride, boron carbide, and silicon nitride.

[0090] Optionally, the material of the interdigital transducer 4 and the first reflection grating 13 and the second reflection grating 7 includes a combination of one or more of copper, aluminum, gold, silver, tungsten, platinum, nickel, chromium, molybdenum, titanium, graphene, copper-aluminum alloy, and aluminum-silicon alloy; the material of the bottom electrode 2 includes a combination of one or more 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.

[0091] In the embodiment of the present application, the energy processing device 5 can be located on the piezoelectric layer 3 and on both sides of the interdigital transducer 4; it can also be located on the bottom electrode 2 and in the same layer as the piezoelectric layer 3, or it can be a part of the piezoelectric layer 3 or the bottom electrode 2 layer. According to the function of the energy processing device 5, it can be divided into three categories. When the energy processing device 5 is used to transmit the zero-order mode, it can be called an energy transmission device; when the energy processing device 5 is used to absorb the zero-order mode, it can be called an energy absorption device; when the energy processing device 5 is used to scatter the zero-order mode, it can be called an energy scattering device. The structures of the above three types of energy processing devices 5 will be described in detail below:

[0092] As for the energy transmission device, it can be the first reflector 13, that is, a non-standard reflector, see Figure 4 , assuming that the distance between the centers of adjacent interdigital electrodes 403 in the IDT 4 is P1, and the distance between the centers of adjacent electrodes in the first reflective grating 13 is set to P2, then P1 is not equal to P2.

[0093] Optionally, at least one of the material of the first reflection grating 13, the duty cycle of the first reflection grating 13, the thickness of the first reflection grating 13, the material of the target layer corresponding to the region of the first reflection grating 13, and the thickness of the target layer corresponding to the region of the first reflection grating 13 is different from the region of the corresponding IDT 4; the target layer includes at least one of the bottom electrode 2, the piezoelectric layer 3, and the supporting substrate 1. Optionally, the entire acoustic wave resonator can be divided into three regions along the first direction, the region of the two energy processing devices 5, and the region of the IDT 4 located between the regions of the two energy processing devices 5 (also referred to as the effective resonance region), so the region of the IDT 4 can refer to the region including the IDT 4, the piezoelectric layer 3 corresponding to the IDT 4, the region of the bottom electrode 2, and the region of the supporting substrate 1. Since the first reflection grating 13 is the energy processing device 5, the region of the first reflection grating 13 can refer to the region of the energy processing device 5, that is, the region including the first reflection grating 13, the piezoelectric layer 3 corresponding to the first reflection grating 13, the region of the bottom electrode 2, and the region of the supporting substrate 1. It can be understood that since the energy processing device 5 is not necessarily composed of the first reflection grating 13, when the energy processing device 5 does not contain the first reflection grating 13, the area of ​​the energy processing device 5 includes the energy processing device 5, the area of ​​the corresponding piezoelectric layer 3, the area of ​​the bottom electrode 2 and the area of ​​the supporting substrate 1.

[0094] In an exemplary embodiment, the bottom electrode 2 and the IDT 4 have no overlapping portion in the non-effective resonance region. Figure 5 The bottom electrode 2 is only distributed in the region of the IDT 4 , so that a dielectric region 11 is provided on both sides of the bottom electrode 2 , respectively, and the dielectric region 11 is located in the region of the first reflective grating 13 .

[0095] In an exemplary embodiment, see Figure 6 , the distance between the centers of adjacent electrodes in the first reflection grid 13 located on the first side is not equal to the distance between the centers of adjacent electrodes in the first reflection grid 13 located on the second side. Specifically, the distance between the centers of adjacent electrodes in the first reflection grid 13 located on the first side may be greater than the distance between the centers of adjacent electrodes in the first reflection grid 13 located on the second side, or the distance between the centers of adjacent electrodes in the first reflection grid 13 located on the first side may be less than the distance between the centers of adjacent electrodes in the first reflection grid 13 located on the second side. Please refer to Figure 7 The distances between the centers of multiple groups of adjacent electrodes in each first reflection grating 13 are not equal. Optionally, the distances between the centers of multiple groups of adjacent electrodes along the first direction may gradually increase or decrease, and the changes in the distances between the centers of the adjacent electrodes of the two first reflection gratings 13 may be different.

[0096] In another exemplary embodiment, see Figure 8 The material of the first reflection grating 13 and the material of the IDT 4 may be different.

[0097] In another exemplary embodiment, see Fig. 9 , a load layer 9 is provided on the first reflective grid 13 .

[0098] In another exemplary embodiment, see Fig.10 The energy processing device 5 is composed of a region of the piezoelectric layer 3 having a groove structure 301 on the surface. The energy processing device 5 can be formed by designing the piezoelectric layer 3 located in the region of the energy processing device 5 to have a groove structure on the surface. Optionally, the groove structure 301 can be formed on the piezoelectric layer 3 by an etching process.

[0099] In another exemplary embodiment, see Fig.11 A second reflection grating 7 is further provided between the first reflection grating 13 and the interdigital transducer 4; the second reflection grating 7 can be called a standard reflection grating; the distance between the centers of adjacent electrodes in the second reflection grating 7 is equal to the distance corresponding to the interdigital electrodes 403. Optionally, the second reflection grating 7 includes no more than 5 electrodes, such as the second reflection grating 7 includes 0, 1, 2, 3, 4 or 5 electrodes.

[0100] In another exemplary embodiment, see Figure 12-13 , the distances between the centers of adjacent electrodes in the two first reflection gratings 13 are equal. Optionally, the two first reflection gratings 13 are symmetrical structures.

[0101] In this disclosure, please continue to refer to Fig.13 The interdigital transducer 4 includes a first bus bar 401 and a second bus bar 402 that are relatively arranged, and a plurality of interdigital electrodes 403 are respectively provided on the first bus bar 401 and the second bus bar 402. The plurality of interdigital electrodes 403 on the first bus bar 401 and the plurality of interdigital electrodes 403 on the second bus bar 402 are arranged alternately along a first direction. Optionally, the period of the interdigital transducer 4 is the distance between the centers of adjacent interdigital electrodes 403 connected to the first bus bar 401, or the distance between the centers of adjacent interdigital electrodes 403 connected to the second bus bar 402.

[0102] In the embodiment of the present application, each group of interdigital electrodes 403 is two adjacent interdigital electrodes 403 connected to the first bus bar 401 and the second bus bar 402 respectively.

[0103] In another exemplary embodiment, the distance between the centers of adjacent electrodes in the first reflective grid 13 varies along the second direction, which is the extension direction of the interdigital electrodes 403 of the interdigital transducer 4. Fig.14 The distance between the centers of adjacent electrodes in the first reflection grid 13 may be gradually increased along the second direction. Optionally, the distance between the centers of adjacent electrodes in the first reflection grid 13 may be gradually decreased along the second direction. Optionally, the two first reflection grids 13 are symmetrical structures. Fig.15 Specifically, the distance between the centers of adjacent electrodes in one first reflective grating 13 may gradually increase along the second direction, and the distance between the centers of adjacent electrodes in the other first reflective grating 13 may gradually decrease along the second direction. Optionally, the two first reflective gratings 13 are anti-symmetric structures. Fig.16 The distance between the centers of adjacent electrodes in the first reflective grating 13 does not change monotonically along the second direction. Optionally, the two first reflective gratings 13 are symmetrical structures or anti-symmetrical structures. Figure 14-16 In the structure shown, the distance between the centers of adjacent electrodes in the first reflective grating 13 has different values ​​at different positions in the second direction. Optionally, the distance between the centers of adjacent electrodes in the first reflective grating 13 may also have different values ​​at different positions in the first direction.

[0104] In another exemplary embodiment, the area of ​​the piezoelectric layer 3 corresponding to the overlapping portion of the bottom electrode 2 and the interdigital transducer 4 in the non-effective resonance area is replaced by the dielectric area 11. Fig.17 The piezoelectric layer 3 is only located in the effective resonance area and the area corresponding to the first reflection grating 13 , while the remaining area is filled with the dielectric area 11 .

[0105] See also Fig.18 , which is a schematic diagram of the structure of a comparative example 1 provided in the embodiment of the present application. Provide structure 1 (i.e. Figure 4 The structure shown), Comparative Example 1 and Figure 4 The difference between the structures shown is that Figure 4 The two sides of the interdigital transducer 4 of the structure shown are respectively provided with a first reflection grating 13, while the two sides of the interdigital transducer 4 in comparative example 1 are respectively provided with a second reflection grating 7, and the distance between the centers of adjacent electrodes of the second reflection grating 7 is equal to the distance between the centers of adjacent interdigital electrodes 403 of the interdigital transducer 4. Among them, the specific structural parameters that are the same as those of comparative example 1 and structure 1 are as follows: the material of the supporting substrate 1 is 4H-SiC; the material of the bottom electrode 2 is platinum, with a thickness of 50nm; the material of the piezoelectric layer 3 is X-cut lithium niobate, with a thickness of 325nm; the material of the interdigital transducer 4 is aluminum / tungsten, with a thickness of 65 / 35nm, and the P1 of the interdigital transducer 4 is 1.65μm. A dielectric layer 6 is also provided between the supporting substrate 1 and the bottom electrode 2, and the material of the dielectric layer 6 is silicon oxide, and has a thickness of 200nm; the target mode is the SH1 mode. The interdigital transducer 4 includes 60 groups of interdigital electrodes 403, and the reflection gratings on both sides include 20 electrodes. Please refer to Fig.19, which shows the admittance curve of a Comparative Example 1 provided by an embodiment of the present application. It can be seen that the SH1 mode can achieve high frequency and large electromechanical coupling coefficient. However, due to the simultaneous presence of transverse and longitudinal electric fields, and the piezoelectric coefficient components unrelated to the main mode in the piezoelectric layer 3, a large number of parasitic modes exist, including the zero-order Rayleigh mode, SH0 mode, and LL-SAW mode. Among them, the sound velocity of the LL-SAW mode is closest to that of the SH1 mode. Therefore, it appears near the resonance frequency of the SH1 mode.

[0106] Please refer to Fig. 20 , which shows a Fig.18 simulation admittance curve corresponding to different numbers of interdigital electrode groups of the shown structure. Except for the number of interdigital electrode groups of the interdigital electrode 403, other parameters are the same as those of Structure 1. It can be seen that increasing or decreasing the number of interdigital electrode groups of the interdigital transducer 4 does not significantly reduce the admittance ratio of the target mode.

[0107] Please refer to Figure 21-22 , which respectively shows the simulation admittance curves corresponding to different P2 provided by an embodiment of the present application. Among them, the number of interdigital electrode groups of the interdigital transducer 4 is 20 groups, the number of electrodes of the first reflection grating 13 is 20, and P2 is 0.9 - 1.1P1 respectively. Other parameters are the same as those of Structure 1 above. It can be seen that the resonance responses of the zero-order Rayleigh mode, SH0 mode, and LL-SAW mode all change with the change of P2. Further, by extracting Fig.21 and Fig. 22 the admittance ratios corresponding to the zero-order Rayleigh mode, SH0 mode, and LL-SAW mode in the results when P2 takes different values, the curve shown in Fig.23 can be obtained. It can be seen that for the SH0 and LL-SAW modes, when P2 > P1, the admittance ratio increases, and when P2 < P1, the admittance ratio significantly decreases. For the zero-order Rayleigh mode, the admittance ratio significantly decreases when P2 is larger or smaller.

[0108] Please refer to Fig.24 , which corresponds to the admittance curves when P2 = 0.95P1 and P2 = P1. The number of interdigital electrode groups of the interdigital transducer 4 is 20 groups, and the other structural parameters are the same as those of Structure 1. It can be seen that the admittance responses of the target mode SH1 in these two cases hardly change, and compared with P2 = P1, the admittance ratios of the zero-order Rayleigh mode, SH0 mode, and LL-SAW mode corresponding to P2 = 0.95P1 all significantly decrease.

[0109] Please refer to Figure 25-26 , which respectively shows Fig.24The corresponding vibration mode diagrams of the SH1 mode at the anti-resonance frequency point when P2=P1 and P2=0.95P1. It can be seen that the vibration of the SH1 mode is concentrated on the IDT 4 in both cases.

[0110] See also Figure 27-28 , which are shown as follows: Fig.24 The vibration mode diagram of the corresponding zero-order Rayleigh mode at the anti-resonance frequency point when P2 = P1 and P2 = 0.95P1. It can be seen that when P2 = P1, the Rayleigh mode has already leaked to both sides. This is because the electromechanical coupling coefficient of this mode is small and more reflection gratings are needed to constrain it. When P2 = 0.95P1, the leakage of the Rayleigh mode to both sides is further enhanced.

[0111] See also Figure 29-30 , which are shown as follows: Fig.24 The vibration mode diagram of the corresponding SH0 mode at the anti-resonance frequency point when P2 = P1 and P2 = 0.95P1. It can be seen that when P2 = P1, the vibration of the SH0 mode is basically concentrated in the area of ​​the interdigital transducer 4. When P2 = 0.95P1, the SH0 mode leaks a lot to both sides.

[0112] See also Figure 31-32 , which are shown as follows: Fig.24 The vibration mode diagrams of the corresponding LL-SAW mode at the anti-resonance frequency point when P2 = P1 and P2 = 0.95P1. It can be seen that when P2 = P1, the vibration of the LL-SAW mode is basically concentrated in the interdigital transducer 4 area. When P2 = 0.95P1, the LL-SAW mode leaks a lot to both sides.

[0113] See also Fig.33 , which shows the corresponding number of electrodes of a different second reflective grating provided in an embodiment of the present application Fig.18 The simulated admittance curve of the structure shown in FIG. Among them, the number of groups of the interdigital electrodes 403 of the interdigital transducer 4 is 20, P2=P1, the number of electrodes of the first reflective grating 13 is 0 to 20, and the other structural parameters are the same as those of structure 1. It can be seen that when the number of electrodes in the first reflective grating 13 is smaller, the admittance ratio of the zero-order mode is smaller. Further, by extracting Fig.33 The admittance ratios corresponding to the zero-order Rayleigh mode, SH0 mode, and LL-SAW mode when P2 takes different values ​​can be obtained as follows: Fig.34 From the curve shown, it can be seen that as the number of electrodes in the first reflector 13 decreases, the admittance ratio of the SH1 mode remains almost unchanged, while the admittance ratios of the zero-order Rayleigh mode, the SH0 mode, and the LL-SAW mode all decrease significantly.

[0114] See also Fig.35, which corresponds to the admittance curve of P2=0.9P1, P2=P1. When P2=0.9P1, the number of electrodes of the first reflector 13 is 4, and when P2=P1, the number of electrodes of the first reflector 13 is 20. The other parameters are the same as those of structure 1. It can be seen that the admittance response of the target mode has almost no change, while the admittance ratios of the zero-order Rayleigh mode, SH0 mode, and LL-SAW mode are greatly reduced, especially for the SH0 mode, whose admittance ratio is compared with Fig.24 The results shown have further decreased.

[0115] See also Fig.36 , which corresponds to P2=0.9P1 and the admittance curve without the first reflector, wherein when P2=0.9P1, the number of electrodes of the first reflector 13 is 4, and the other parameters are the same as those of structure 1. It can be seen that the admittance of the SH0 mode and the LL-SAW mode is lower than that without the first reflector 13. Therefore, the use of a non-standard reflector (i.e., the first reflector 13) is a very simple and effective solution to suppress the zero-order mode.

[0116] Based on the above analysis, it can be seen that by arranging a first reflection grating 13 on both sides of the IDT 4, the distance (P2) of the first reflection grating 13 is not equal to the distance (P1) of the IDT 4, so that the admittance ratios of the zero-order Rayleigh mode, SH0 mode, and LL-SAW mode are significantly reduced, but the admittance response to the target mode SH1 is almost unchanged (see Figure 24-32 ), and further, as the number of electrodes in the first reflector 13 decreases, the admittance ratio of the SH1 mode remains almost unchanged, while the admittance ratios of the zero-order Rayleigh mode, the SH0 mode, and the LL-SAW mode all decrease significantly (see Figure 33-36 ), which shows that the use of a non-standard reflection grating (i.e., the first reflection grating 13) is a very simple and effective solution for suppressing the zero-order mode. In addition, as the number of groups of the interdigital electrodes 403 of the interdigital transducer 4 increases or decreases, the admittance ratio of the target mode will not be significantly reduced, so the number of groups of the interdigital electrodes 403 of the interdigital transducer 4 can be designed according to requirements, including at least one group of interdigital electrodes 403.

[0117] The above is a description of the energy transmission device. The following will describe the energy absorption device. The energy absorption device can be a structure including a high damping layer 8; the high damping layer 8 includes a polymer material or a damaged layer; the damaged layer is formed by ion implantation into the piezoelectric film. Fig.37 ,and Figure 4 Compared with the structure shown in FIG. 1 , the two sides of the IDT 4 are structures made of high damping materials. Specifically, the piezoelectric layer 3 may be located only below the IDT 4, and the high damping layer 8 is provided in the remaining area.

[0118] See also Fig.38 , which is shown in the embodiment of the present application Figure 4 The simulated admittance curves corresponding to different numbers of interdigital electrodes when the structure shown has no reflection grating, wherein the number of groups of interdigital electrodes 403 in the interdigital transducer 4 can be set to 15 groups, 20 groups, 40 groups, and 60 groups respectively, and the number of electrodes of the first reflection grating 13 is 0, that is, there is no first reflection grating 13, and the other structural parameters are the same as those of the structure 1. Please refer to Fig.39 , which is shown as a method provided by the embodiment of the present application Fig.37 The simulated admittance curves corresponding to different groups of interdigital electrodes, other parameters are the same as above Fig.38 The same. Further, from Fig.38 and Fig.39 The admittance ratios corresponding to the zero-order Rayleigh mode, SH0 mode, LL-SAW mode and SH1 mode extracted from the IDT 4 when the number of groups is different can be obtained as follows: Fig.40 The curve shown in Figure 2, where the solid line corresponds to Fig.39 , that is, there is an energy absorption device in the structure, and the dotted line corresponds to Fig.38 . It can be seen that as the number of groups of the interdigital electrodes 403 of the interdigital transducer 4 decreases, the admittance ratios of all modes decrease to varying degrees, among which the decrease in the SH1 mode is much smaller than that of other modes. For the SH1 mode, the change with or without the energy absorption device is small, and the effect of the energy absorption device on the Rayleigh mode is also small, because the energy of the Rayleigh mode has been leaked to both sides in large quantities. For the SH0 and LL-SAW modes, when the energy absorption device is present, the admittance ratio drops significantly. Therefore, adding an energy absorption device is an effective means to suppress the zero-order mode.

[0119] See also Fig.41 , which is shown in the embodiment of the present application Fig.37 The simulated admittance curves corresponding to the structures with and without the energy absorption device are shown, wherein the number of groups of the interdigital electrodes 403 is 20, there is no first reflector 13, and the other structural parameters are the same as those of structure 1. It can be seen that after adding the energy absorption device, the admittance response of the SH1 mode has almost no change, while the admittance ratio of the SH0 and LL-SAW modes has dropped significantly.

[0120] In another exemplary embodiment, see Fig.42 The high damping layer 8 can also be arranged on the piezoelectric layer 3 and located on both sides of the interdigital transducer 4 .

[0121] In another exemplary embodiment, see Fig.43 ,and Figure 3 Compared with the structure shown in the figure, the first reflection grating 13 may also be covered with a high damping layer 8 .

[0122] In another exemplary embodiment, it is also possible to Fig.37 On the basis of the structure, a reflection grating is provided on both sides of the interdigital transducer 4, and the reflection grating is located on the piezoelectric layer 3. Optionally, please refer to Fig.44 The reflective grating may specifically be the second reflective grating 7, or may be Fig.45 The first reflective grating 13 shown is not limited here.

[0123] The above is a description of the energy absorption device. The energy scattering device will be described below. The energy scattering device can be a load structure 12, a region of the piezoelectric layer 3 having a through hole 10, or a region of the bottom electrode 2 with an irregular shape.

[0124] In an exemplary embodiment, see Fig.46 , irregular load structures 12 can be respectively arranged on both sides of the interdigital transducer 4, and the load structures 12 are located on the piezoelectric layer 3, and these irregular load structures 12 can constitute energy scattering devices. Optionally, the top view of the load structure 12 can be a triangle, a rectangle, a rhombus, a pentagon or a combination thereof, which is not limited here.

[0125] In another exemplary embodiment, see Fig.47 The energy scattering device located on both sides of the IDT 4 may be composed of a plurality of through holes 10 of the piezoelectric layer 3 located on both sides of the IDT 4. The structure of the through holes 10 is not limited to circular, rectangular, diamond, etc., that is, the structure of the through holes 10 may be irregular, as long as the through holes 10 are distributed on both sides of the IDT 4.

[0126] In another exemplary embodiment, see Fig.48 The bottom electrode 2 includes a first region, a second region and a third region sequentially arranged along a first direction, wherein the second region is located in the region of the interdigital transducer 4 and may be a rectangle, the first region and the third region are respectively located below a first reflection grating 13, i.e., the region of the first reflection grating 13, and the first region and the second region may be irregular shapes, so that the first region and the second region respectively constitute an energy scattering device.

[0127] The high-frequency acoustic wave resonator provided in the embodiment of the present application can achieve scattering, transmission or absorption of the zero-order mode by respectively arranging an energy processing device 5 on both sides of the interdigital transducer 4, thereby minimizing the Q value of the zero-order mode and reducing the influence of related stray passbands without affecting the target mode.

[0128] On the other hand, an embodiment of the present application provides a high-frequency acoustic wave resonator, which is formed by cascading at least two of the above-mentioned high-frequency acoustic wave resonators.

[0129] On the other hand, an embodiment of the present application provides a communication device, which includes the above-mentioned acoustic wave resonator; the communication device includes at least one of a filter, a duplexer and a multiplexer.

[0130] The above are only optional embodiments of the present application and are 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. A high-frequency acoustic wave resonator, characterized in that: It includes a supporting substrate, a bottom electrode, a piezoelectric layer and an interdigital transducer arranged in sequence from bottom to top; The distances corresponding to any two groups of interdigital electrodes in the IDT are equal; the distance corresponding to each group of the interdigital electrodes is the distance between the centers of two adjacent interdigital electrodes in the IDT; the target mode of the high-frequency acoustic wave resonator is a high-order acoustic wave mode excited by a longitudinal electric field; the product of the period of the IDT and the resonant frequency of the target mode is less than the acoustic velocity of the supporting substrate; the period of the IDT is twice the distance corresponding to the interdigital electrodes; The interdigital transducer includes a first side and a second side arranged along a first direction; the first direction is the width direction of the interdigital electrode; an energy processing device is respectively provided on the first side and the second side; the energy processing device is used to scatter, transmit or absorb the zero-order mode.

2. The high-frequency acoustic wave resonator according to claim 1, characterized in that: The energy processing device is used to transmit the zero-order mode; When the energy processing device is a first reflective grid, the distance between the centers of adjacent electrodes in the first reflective grid is not equal to the distance corresponding to the interdigitated electrodes; At least one of the material of the first reflection grating, the duty cycle of the first reflection grating, the thickness of the first reflection grating, the material of the target layer corresponding to the area of ​​the first reflection grating, and the thickness of the target layer corresponding to the area of ​​the first reflection grating is different from the corresponding area of ​​the interdigital transducer; the target layer includes at least one of the bottom electrode, the piezoelectric layer and the supporting substrate.

3. The high-frequency acoustic wave resonator according to claim 1, characterized in that: The energy processing device is used to absorb the zero-order mode; The energy processing device includes a high damping layer; The high damping layer includes a polymer material or a damaged layer; the damaged layer is formed by implanting ions into the piezoelectric film.

4. The high-frequency acoustic wave resonator according to claim 1, characterized in that: The energy processing device is used to scatter the zero-order mode; The energy processing device includes a load structure, a region of the piezoelectric layer having a through hole, or a region of an irregularly shaped bottom electrode.

5. The high-frequency acoustic wave resonator according to claim 2, characterized in that: A second reflection grating is further provided between the first reflection grating and the interdigital transducer; The distance between the centers of adjacent electrodes in the second reflective grid is equal to the distance corresponding to the interdigital electrodes; The second reflector includes no more than five electrodes.

6. The high-frequency acoustic wave resonator according to claim 2, characterized in that: The distance between the centers of adjacent electrodes in the first reflection grid located on the first side is not equal to the distance between the centers of adjacent electrodes in the first reflection grid located on the second side.

7. The high-frequency acoustic wave resonator according to claim 2, characterized in that: A load layer is provided on the first reflective grating, and / or the two first reflective gratings are of symmetrical structure or anti-symmetrical structure.

8. The high-frequency acoustic wave resonator according to claim 2, characterized in that: The energy processing device includes a region of a piezoelectric layer having a groove structure on its surface.

9. The high-frequency acoustic wave resonator according to claim 2, characterized in that: The distance between the centers of adjacent electrodes in the first reflection grid has different values ​​at different positions in the first direction or the second direction; The second direction is an extending direction of the interdigital electrodes of the IDT.

10. The high-frequency acoustic wave resonator according to claim 1, characterized in that: There is no overlapping portion between the bottom electrode and the IDT in the ineffective resonance region, or the region of the piezoelectric layer corresponding to the overlapping portion between the bottom electrode and the IDT in the ineffective resonance region is replaced by a dielectric region.

11. The high-frequency acoustic wave resonator according to claim 1, characterized in that: The target mode is one of a high-order Lamb wave and a high-order horizontal shear wave.

12. A high-frequency acoustic wave resonator, characterized in that: It is formed by cascading at least two of the high-frequency acoustic wave resonators described in any one of claims 1 to 11.

13. A communication device, characterized in that: comprising an acoustic wave resonator as claimed in any one of claims 1 to 11; The communication device includes at least one of a filter, a duplexer and a multiplexer.

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