A sound wave resonator and communication device

Abstract

The present invention relates to the field of microelectronics technology, and in particular to an acoustic wave resonator and a communication device. The acoustic wave resonator includes a supporting substrate and a resonant cavity structure, the resonant cavity structure is located on the supporting substrate, and the resonant cavity structure includes an impedance control region and a forked electrode; by adjusting the structural parameters and performance parameters of the impedance control region, the distribution of the acoustic wave component in the thickness direction of the acoustic wave resonator is adjusted in combination with the mass loading effect, and the leakage of the target high sound velocity mode in the thickness direction is reduced, so that the energy of the target acoustic wave mode can be effectively constrained, and the high sound velocity acoustic wave mode can be excited and utilized to obtain a high-frequency resonant response; the impedance matching between the area covered by the forked electrode and the area not covered by the forked electrode is adjusted, the acoustic wave speed is adjusted, the fusion of the acoustic wave mode is realized, the pseudo-mode spurious response is suppressed, and the electromechanical coupling coefficient is improved.

Description

Technical Field

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

[0002] With the rapid development of mobile communication technology, the communication frequency bands of 3GHz and below are becoming more and more crowded. In order to maintain the stability and fidelity of terminal signal transmission, the out-of-band suppression level and band edge steepness of filter devices are required to be higher and higher. In order to meet this development demand, on the one hand, it is necessary to design a mode without spurious response or eliminate spurious responses falling in the key frequency band, and on the other hand, it is necessary to expand the operating frequency band of mobile devices to a higher frequency band.

[0003] For surface acoustic wave filter devices, their operating frequency depends on the acoustic wave phase velocity (sound velocity) and the finger line width. Since the sound velocity of the target acoustic wave modes such as Rayleigh waves and horizontal shear waves in traditional piezoelectric single crystals does not exceed 4200m / s, in order to expand the operating frequency to 5GHz and achieve high frequency, the finger line width can only be continuously compressed. In the high-frequency and high-power working environment, the narrow metal electrode will be severely cracked and splashed under heavy cycle stress impact, which will lead to the rapid failure of the filter device and reduce the reliability of the device. In order to avoid the above problems, it is possible to consider exciting an acoustic wave mode with a high sound velocity. For example, for a solid-state assembled surface acoustic wave resonator, the longitudinal leakage wave mode is an acoustic wave mode with a high sound velocity, and its sound velocity can reach 5500m / s or more, which is at least 1.3 times the sound velocity of the above-mentioned traditional acoustic waves. Then when this acoustic wave mode is excited and the operating frequency is maintained at the same level as the traditional acoustic wave device, the finger line width can be increased to 1.3 times the original, which is beneficial to improving the temperature stability and power tolerance of the device and reducing the difficulty and cost of the preparation process. However, due to the limited research on the characteristics of high-acoustic-velocity substrate structures and longitudinal leakage wave modes, as well as the existence of stray pseudo-modes, the longitudinal leakage wave resonator structure has not yet been commercialized. There are also other solutions to improve the resonant frequency of solid-state assembled surface acoustic wave devices, and develop new high-acoustic-velocity substrate structures, such as a multilayer substrate structure containing a Bragg reflector. In order to achieve a good acoustic wave reflection effect, the material types and thicknesses of the high and low impedance layers must be precisely designed. In order to reduce the feed-through capacitance, the metal layer as the high impedance layer must also be patterned. However, the design and preparation are relatively complicated. There are also studies that use suspended membrane structures to design and excite high-acoustic-velocity Lamb wave devices, but the stability and mass production yield of suspended membrane devices still need further breakthroughs. Therefore, how to provide a high-frequency longitudinal leakage wave resonator with a simple structure and simple preparation is still a hot topic for continuous research by relevant technical personnel in this field. Summary of the invention

[0004] In order to solve the above technical problems, the present application discloses, on one hand, an acoustic wave resonator, which comprises:

[0005] a supporting substrate;

[0006] A resonant cavity structure, the resonant cavity structure is located on a supporting substrate, and the resonant cavity structure includes an impedance control region and interdigital electrodes; by adjusting the structural parameters and performance parameters of the impedance control region, the distribution of the acoustic wave component in the thickness direction of the acoustic wave resonator can be adjusted, and the impedance matching between the area covered by the interdigital electrodes and the area not covered by the interdigital electrodes can be adjusted; the target mode of the acoustic wave resonator is generated by electric field excitation in the direction of acoustic wave propagation and / or in the thickness direction of the acoustic wave resonator.

[0007] In a feasible embodiment, the resonant cavity structure further includes a piezoelectric layer;

[0008] The piezoelectric layer is located on a supporting substrate;

[0009] The interdigitated electrodes are located on the piezoelectric layer;

[0010] The impedance control region is located on the interdigital electrodes, or the impedance control region is located in a blank region of the piezoelectric layer; the blank region includes the spacing region between the electrode fingers of the interdigital electrodes.

[0011] In a feasible embodiment, the material of the impedance control region is a piezoelectric material;

[0012] The interdigitated electrodes are located on a supporting substrate;

[0013] The impedance control region covers the interdigitated electrodes.

[0014] In a feasible embodiment, it further includes a functional layer;

[0015] The functional layer is located on the impedance control region.

[0016] In one feasible embodiment, the performance parameters of the impedance control region include the material of the impedance control region;

[0017] The structural parameters of the impedance control region include the position and size of the impedance control region.

[0018] In a feasible embodiment, the material of the impedance control region includes at least one of aluminum nitride, silicon nitride, gallium nitride, silicon oxide, silicon carbide, diamond, diamond-like carbon, sapphire, magnesium oxide, aluminum oxide, silicon, boron carbide, boron nitride, lithium tantalate, lithium niobate and potassium niobate;

[0019] When the period of the interdigital electrodes is equal to the wavelength λ of the acoustic wave, the thickness range of the impedance control region is 0.01λ to 0.15λ.

[0020] In a feasible embodiment, the slow shear wave speed of the supporting substrate is greater than or equal to 5500 m / s;

[0021] The support substrate material includes at least one of silicon carbide, diamond, diamond-like carbon, silicon, sapphire, gallium nitride, boron carbide, boron nitride and aluminum nitride.

[0022] In a feasible embodiment, the target acoustic wave mode includes a quasi-longitudinal leakage wave, a quasi-high-order shear wave, or a quasi-high-order Lamb wave;

[0023] The product of the wavelength of the acoustic wave and the resonance frequency of the target acoustic wave mode is greater than 65% of the slow shear wave sound velocity of the supporting substrate and less than the slow shear wave sound velocity of the supporting substrate.

[0024] In a feasible embodiment, the piezoelectric layer material includes lithium tantalate, lithium niobate or potassium niobate;

[0025] When the period of the interdigital electrodes is equal to the wavelength λ of the acoustic wave, the thickness of the piezoelectric layer ranges from 0.15λ to 0.4λ.

[0026] In one possible embodiment, the energy of the target mode is concentrated within the resonant cavity structure;

[0027] The thermal conductivity of the functional layer is greater than the thermal conductivity of the piezoelectric layer, and the sound velocity of the functional layer is greater than the body wave sound velocity of the piezoelectric layer;

[0028] The material of the functional layer includes at least one of aluminum nitride, silicon nitride, gallium nitride, silicon carbide, diamond, diamond-like carbon, sapphire, magnesium oxide, aluminum oxide, silicon, boron carbide, boron nitride, lithium tantalate, lithium niobate and potassium niobate;

[0029] When the period of the interdigital electrodes is equal to the wavelength λ of the acoustic wave, the thickness of the functional layer ranges from 0.015λ to 0.15λ.

[0030] In a feasible embodiment, the material of the interdigital electrodes includes an alloy of one or more of copper, silver, gold, aluminum, platinum, nickel, molybdenum, tungsten, chromium, and titanium; or, the interdigital electrodes are electrodes stacked with one or more metals;

[0031] When the interdigital electrodes are single-layer electrodes and the period of the interdigital electrodes is equal to the wavelength λ of the acoustic wave, the thickness range of the interdigital electrodes is 0.02λ to 0.12λ.

[0032] The present application discloses, in another aspect, a communication device, which includes the above-mentioned acoustic wave resonator;

[0033] The communication device includes at least one of a filter, a duplexer, and a multiplexer.

[0034] By adopting the above technical solution, the acoustic wave resonator provided by the present application has the following beneficial effects:

[0035] The acoustic wave resonator includes a supporting substrate and a resonant cavity structure, the resonant cavity structure is located on the supporting substrate, and the resonant cavity structure includes an impedance control region and a forked electrode; by adjusting the structural parameters and performance parameters of the impedance control region, the distribution of the acoustic wave component in the thickness direction of the acoustic wave resonator is adjusted in combination with the mass loading effect, and the leakage of the target high sound velocity mode in the thickness direction is reduced, so that the energy of the target acoustic wave mode can be effectively constrained, and the high sound velocity acoustic wave mode can be excited and utilized to obtain a high-frequency resonant response; the impedance matching between the area covered by the forked electrode and the area not covered by the forked electrode is adjusted, the sound velocity of the acoustic wave is adjusted, the fusion of the acoustic wave mode is realized, the pseudo-mode spurious response is suppressed, and the electromechanical coupling coefficient is improved. The acoustic wave resonator proposed in the present application can effectively excite the high sound velocity acoustic wave mode and eliminate the pseudo-mode spurious response, so that a high-frequency device without spurious response can be obtained while maintaining the line width of the forked electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] 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.

[0037] Figure 1 It is a structural schematic diagram of an existing acoustic wave resonator;

[0038] Figure 2 is a simulated admittance curve corresponding to comparative example 1;

[0039] Figure 3 yes Figure 2 Mode shape diagram corresponding to the resonance peak (i);

[0040] Figure 4 yes Figure 2 Mode shape diagram corresponding to the resonance peak (ii);

[0041] Figure 5 is a simulated admittance curve diagram of the resonator in the filter constructed based on Comparative Example 1;

[0042] Figure 6 This is a frequency-scattering parameter diagram of the filter built based on Comparative Example 1;

[0043] Figure 7 1 is a simulated admittance curve diagram of comparative example 1 under different acoustic wave wavelengths;

[0044] Figure 8 is a schematic structural diagram of a first exemplary acoustic wave resonator of the present application;

[0045] Fig. 9is an exemplary comparison diagram of the admittance response of Comparative Example 1 and Example 1 of the present application;

[0046] Fig.10 This is an example of an Fig. 9 The vibration mode diagram of the acoustic wave mode corresponding to the main resonance peak of Example 1;

[0047] Fig.11 is a distribution diagram of the x, y and z components of the acoustic wave mode of an exemplary embodiment 1 of the present application in the thickness direction;

[0048] Fig.12 This is an exemplary simulated admittance curve of a resonator in a filter constructed based on Example 1 of the present application;

[0049] Fig.13 This is an exemplary frequency-scattering parameter diagram of a filter constructed based on Example 1 of the present application;

[0050] Figure 14-16 They are the existing structure and Figure 8 Simulated admittance curve of the structure;

[0051] Figure 17-19 They are the existing structures and Figure 8 Simulated admittance curve of the structure;

[0052] Fig. 20 This is an example of an Figure 17-19 The vibration mode diagrams corresponding to Examples 5, 6 and 7 respectively;

[0053] Figure 21-22 They are the existing structures and Figure 8 Simulated admittance curve of the structure;

[0054] Fig.23 is a comparison diagram of the admittance response of a comparative example 10 and an example 10 of the present application;

[0055] Fig.24 is a comparison diagram of the admittance response of a comparative example 11 and an example 11 of the present application;

[0056] Fig.25 is a schematic structural diagram of a second exemplary acoustic wave resonator of the present application;

[0057] Fig.26 is a schematic structural diagram of a third exemplary acoustic wave resonator of the present application;

[0058] Fig. 27 is an exemplary comparison diagram of the admittance response of Comparative Example 1 and Example 12 of the present application;

[0059] Fig.28 This is an example of an Fig. 27 The vibration mode diagram of the acoustic wave mode corresponding to the main resonance peak of Example 12;

[0060] Fig.29 is a distribution diagram of x, y and z components of the acoustic wave mode of an exemplary embodiment 12 of the present application in the thickness direction;

[0061] Fig.30 is an exemplary comparison diagram of the admittance response of Comparative Example 1 and Example 13 of the present application;

[0062] Fig.31 is an exemplary comparison diagram of the admittance response of Comparative Example 1 and Example 14 of the present application;

[0063] Fig.32 is a vibration mode diagram of a sound wave mode corresponding to a main resonance peak of an exemplary embodiment 13 of the present application;

[0064] Fig.33 is a distribution diagram of x, y and z components of the acoustic wave mode of an exemplary embodiment 13 of the present application in the thickness direction;

[0065] Figure 34-35 They are Figure 1 Structure and Fig.25 Impedance analysis diagram corresponding to the structure;

[0066] Fig.36 is a schematic structural diagram of a fourth exemplary acoustic wave resonator of the present application;

[0067] Fig.37 is a schematic structural diagram of a fifth exemplary acoustic wave resonator of the present application;

[0068] Fig.38 is an exemplary comparison diagram of the admittance response of Comparative Example 1 and Example 15 of the present application;

[0069] Fig.39 is an exemplary comparison diagram of the admittance response of Comparative Example 1 and Example 16 of the present application;

[0070] Fig.40 is an exemplary comparison diagram of the admittance response of Comparative Example 1 and Example 17 of the present application;

[0071] Fig.41 This is an example of an Figure 38-40 The vibration mode diagrams of the acoustic wave modes of the main resonance peaks corresponding to Examples 15, 16 and 17 respectively;

[0072] Fig.42 is a schematic structural diagram of a sixth exemplary acoustic wave resonator of the present application;

[0073] Fig.43 is a schematic structural diagram of a seventh exemplary acoustic wave resonator of the present application;

[0074] Fig.44 It is a comparison diagram of the admittance response of a comparative example 1 and an example 18 of the present application;

[0075] Fig.45 This is an example of an Fig.44 The vibration mode diagram of the acoustic wave mode corresponding to the main resonance peak of Example 18;

[0076] Fig.46 is a distribution diagram of x, y and z components of the acoustic wave mode of an exemplary embodiment 18 of the present application in the thickness direction;

[0077] Figures 47-49 The existing structure and the impedance control zone materials are shown in Figure 2. Fig.43 Comparison of the structure's admittance response;

[0078] Fig.50 is a vibration mode diagram of the acoustic wave mode corresponding to the main resonance peak of Examples 19, 20 and 21 of the present application;

[0079] Fig.51 This is an example of an Fig.43 Distribution of the x, y and z components of the acoustic wave mode corresponding to the structure in the thickness direction;

[0080] Figure 52-53 They are Fig.42 Structure and Fig.43 Impedance analysis diagram corresponding to the structure.

[0081] The following is a supplementary description of the attached drawings:

[0082] 1-support substrate; 2-resonant cavity structure; 21-impedance control region; 22-interdigitated electrodes; 23-piezoelectric layer; 3-functional layer. DETAILED DESCRIPTION

[0083] 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.

[0084] 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.

[0085] 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.

[0086] See also Figure 1 , which shows a schematic diagram of the structure of an existing acoustic wave resonator, i.e., a schematic diagram of the structure of comparative example 1, which includes a supporting substrate 1, a piezoelectric layer 23, and a forked electrode 22 arranged in sequence from bottom to top. The material of the piezoelectric layer 23 is a rotated YX-cut lithium tantalate LiTaO3, and the material of the supporting substrate 1 is silicon carbide (4H-SiC); the forked electrode 22 is an aluminum electrode with a thickness of 100nm; the piezoelectric layer 23 is a lithium tantalate single crystal film with an Euler angle of (46, 48, 0), which can also be called a rotated YX42°LiTaO3, with a thickness of 400nm; the supporting substrate 1 is a 4H-SiC high-acoustic-velocity supporting substrate, and the acoustic wave wavelength λ of comparative example 1 is equal to the period of the forked electrode 22 (which can refer to the distance between the centers of adjacent electrode fingers on the same bus bar in the forked electrode 22), and the wavelength λ is 1.4μm.

[0087] When a voltage signal is applied to the device, the interdigital electrodes 22 generate an excitation electric field. The simulated admittance curve of the corresponding resonator is as follows: Figure 2 As shown in the figure, it can be seen that this device structure excites two split resonance peaks (i) and (ii), and the corresponding mode vibration shapes are as follows: Figure 3 and 4 As shown in the vibration diagram (the lighter the color in the vibration diagram, the larger the deformation or the more intense the vibration), the two sound wave modes are longitudinal leakage wave modes with different phases. When one of the modes resonates more strongly, it can be called the main mode. In this way, the sound speed of mode (i) is about 6000m / s, and the electromechanical coupling coefficient is 7.22%; the other is called a pseudo mode, so the sound speed of mode (ii) is about 6300m / s, and the electromechanical coupling coefficient When the longitudinal leakage wave main mode is used as the target mode to build a filter, Figure 5-6 As shown, due to the pseudo-mode response of the series and parallel resonators ( Figure 5 and Figure 6 Marked (ii) and (ii')) will cause serious passband collapse and band edge loss in the filter response, and will also introduce out-of-band spurious responses, affecting the out-of-band suppression level. In the embodiment of the present application, S21 represents the transmission coefficient and S11 represents the reflection coefficient. Figure 7 The simulated admittance curves of the corresponding resonators are shown when the thickness of the LiTaO3 film is kept constant and the wavelength of the acoustic wave is adjusted continuously, such as λ is 1.2μm, 1.4μm, 1.6μm, and 1.8μm, respectively. At this time, the thickness of YX42° LiTaO3 is 400nm. Obviously, no matter how the ratio of the acoustic wave wavelength and the thickness of the piezoelectric film is adjusted, the pseudo mode always exists with the main mode, which will seriously affect the passband response and filtering performance of the device.

[0088] To do this, see Figure 8, which is a schematic diagram of the structure of the first acoustic wave resonator exemplified in the present application. The acoustic wave resonator includes a supporting substrate 1 and a resonant cavity structure 2, the resonant cavity structure 2 is located on the supporting substrate 1, and the resonant cavity structure 2 includes an impedance control region 21 and a forked electrode 22; by adjusting the structural parameters and performance parameters of the impedance control region 21, the distribution of the acoustic wave component in the thickness direction of the acoustic wave resonator is adjusted in combination with the mass loading effect, and the leakage of the target high sound velocity mode in the thickness direction is reduced, so that the energy of the target acoustic wave mode can be effectively constrained, and the high sound velocity acoustic wave mode is excited and utilized to obtain a high-frequency resonant response. The acoustic wave resonator proposed in the present application can effectively excite the high sound velocity acoustic wave mode and eliminate the pseudo-mode spurious response, so that a high-frequency device without spurious response can be obtained while maintaining the line width of the forked electrode 22. It is also possible to adjust the impedance matching between the area covered by the forked electrode 22 and the area not covered by the forked electrode 22, adjust the acoustic wave speed, realize the fusion of the acoustic wave mode, suppress the pseudo-mode spurious response, and improve the electromechanical coupling coefficient. Optionally, the target mode of the acoustic wave resonator is generated by electric field excitation in the direction of acoustic wave propagation and in the thickness direction of the acoustic wave resonator; Optionally, the target mode of the acoustic wave resonator is generated by electric field excitation in the direction of acoustic wave propagation. Optionally, the target mode of the acoustic wave resonator is generated by electric field excitation in the thickness direction of the acoustic wave resonator.

[0089] The rotated Y-cut piezoelectric single crystal, due to its strong anisotropy, will simultaneously excite a pseudo-mode excited by the longitudinal electric field component when exciting the longitudinal leakage wave mode. The vibration shape and frequency of the pseudo-mode are very close to the target main mode, so a spurious response will be introduced at the filter passband response, band edge or out-of-band position. The above-mentioned acoustic wave resonator provided in the present application can excite a high-speed sound mode without clutter, solving the above-mentioned problem.

[0090] In a feasible embodiment, the performance parameters of the impedance control region 21 include the material of the impedance control region 21 ; the structural parameters of the impedance control region 21 include the position and size of the impedance control region 21 .

[0091] In a feasible embodiment, the material of the impedance control zone 21 includes at least one of aluminum nitride, silicon nitride, gallium nitride, silicon oxide, silicon carbide, diamond, diamond-like carbon, sapphire, magnesium oxide, aluminum oxide, silicon, boron carbide, boron nitride, lithium tantalate, lithium niobate and potassium niobate; when the period of the interdigitated electrode 22 is equal to the wavelength λ of the sound wave, the thickness range of the impedance control zone 21 is 0.01λ~0.15λ.

[0092] In a feasible embodiment, the slow shear wave velocity of the support substrate 1 is greater than or equal to 5500 m / s; the material of the support substrate 1 includes at least one of silicon carbide, diamond, diamond-like carbon, silicon, sapphire, gallium nitride, boron carbide, boron nitride and aluminum nitride.

[0093] In a feasible embodiment, the target acoustic wave mode includes a quasi-longitudinal leakage wave, a quasi-high-order shear wave or a quasi-high-order Lamb wave; the product of the wavelength of the acoustic wave and the resonant frequency of the target acoustic wave mode is greater than 65% of the slow shear wave velocity of the supporting substrate 1, and is less than the slow shear wave velocity of the supporting substrate 1.

[0094] In a feasible embodiment, the material of the piezoelectric layer 23 includes lithium tantalate, lithium niobate or potassium niobate; when the period of the interdigital electrodes 22 is equal to the wavelength λ of the sound wave, the thickness of the piezoelectric layer 23 ranges from 0.15λ to 0.4λ.

[0095] In a feasible embodiment, the energy of the target mode is concentrated in the resonant cavity structure 2 .

[0096] In a feasible embodiment, the thermal conductivity of the functional layer 3 is greater than the thermal conductivity of the piezoelectric layer 23 , and the acoustic velocity of the functional layer 3 is greater than the body wave acoustic velocity of the piezoelectric layer 23 .

[0097] In a feasible embodiment, the material of the functional layer 3 includes at least one of aluminum nitride, silicon nitride, gallium nitride, silicon oxide, silicon carbide, diamond, diamond-like carbon, sapphire, magnesium oxide, aluminum oxide, silicon, boron carbide, boron nitride, lithium tantalate, lithium niobate and potassium niobate; when the period of the interdigitated electrode 22 is equal to the wavelength λ of the sound wave, the thickness of the functional layer 3 ranges from 0.015λ to 0.15λ.

[0098] In a feasible embodiment, the material of the interdigitated electrode 22 includes an alloy composed of one or more of copper, silver, gold, aluminum, platinum, nickel, molybdenum, tungsten, chromium, and titanium; or, the interdigitated electrode 22 is an electrode of one or more metal stacks; when the interdigitated electrode 22 is a single-layer electrode and the period of the interdigitated electrode 22 is equal to the wavelength λ of the sound wave, the thickness range of the interdigitated electrode 22 is 0.02λ~0.12λ.

[0099] By adjusting the material, position and size of the impedance control area 21, the acoustic impedance of the acoustic resonator and the distribution of the acoustic wave components in the thickness direction of the structure can be adjusted, so as to effectively excite the acoustic wave mode with high acoustic velocity and obtain a high-frequency resonant response; and by adjusting the impedance matching between the covered area and the uncovered area of ​​the forked electrode 22, the acoustic wave velocity can be adjusted to achieve the fusion of the acoustic wave mode, suppress the pseudo-mode spurious response, and improve the electromechanical coupling coefficient. Specifically, according to the upper and lower positional relationship between the impedance control area 21 and the forked electrode 22, it can be classified into two categories, one is that the impedance control area 21 covers the forked electrode 22, and the other is that the impedance control area 21 is located in the blank area of ​​the layer where the forked electrode 22 is located, and the blank area includes the spacing area between the electrode fingers of the forked electrode 22.

[0100] In the case where the impedance control region 21 covers the interdigital electrodes 22, the following acoustic wave resonators may be included, as shown in the following examples for details.

[0101] Please continue reading Figure 8 , the first acoustic wave resonator includes a supporting substrate 1, a piezoelectric layer 23, a forked electrode 22 and an impedance control region 21 covering only the forked electrode 22, which are arranged in sequence from bottom to top. The impedance control region 21 is not arranged in the blank area of ​​the layer where the forked electrode 22 is located, and the blank area may include the spacing area between the electrode fingers of the forked electrode 22. Exemplarily, the forked electrode 22 is a metal aluminum electrode with a thickness of 100nm; the piezoelectric layer 23 is LiTaO3 rotated YX42° with a thickness of 400nm; the supporting substrate 1 is 4H-SiC, and the acoustic wave wavelength of the device is 1.4μm. When the material of the impedance control region 21 is aluminum nitride AlN with a thickness of 96.5nm, the simulation admittance curve results of the corresponding resonator (which can be called Example 1) and the comparison with the resonator response of Comparative Example 1 are detailed in FIG. Fig. 9 ,in, Fig. 9 The acoustic mode vibration shape corresponding to the main resonance peak of Example 1 is as follows Fig.10 As shown, the distribution of the x, y and z components of the acoustic mode in the thickness direction is shown in Fig.11 As shown. Fig. 9 It can be seen that when using Example 1, only one main resonance peak is excited, the pseudo mode no longer exists, and pure mode excitation can be obtained. Fig.10 and Fig.11 According to the vibration mode and the distribution of the acoustic wave components in the thickness direction, it can be judged that the acoustic wave mode corresponding to the main resonance peak is a quasi-high-order Lamb wave mode, and its sound velocity is about 6100m / s. Under this structural parameter, it can reach up to 6300m / s, which is slightly higher than the main mode sound velocity excited in the traditional structure; in addition, the electromechanical coupling coefficient of this quasi-high-order Lamb wave mode is is 7.94%, slightly larger than the main mode excited in the traditional structure This is conducive to obtaining higher frequency and wider bandwidth applications. On the other hand, AlN has high thermal conductivity and a large elastic coefficient, which can effectively improve the heat dissipation performance and inhibit deformation, which is conducive to improving the heat dissipation performance of the device, reducing the operating temperature and frequency temperature drift of the device, and improving the temperature stability of the device. When the mode excitation is pure, the admittance response of the filter built with this new resonator and the simulated scattering parameter response are as follows Fig.12 and 13As shown, the passband is flat, the band edge is steep, and the out-of-band suppression is high, which is an ideal filter response. This example shows that by using AlN as the impedance control area 21, the impedance of the area covered by the interdigital electrode 22 is controlled, and the distribution of the acoustic wave component in the thickness is mainly x-component, the acoustic wave energy of the high-speed quasi-high-order Lamb wave mode is effectively confined in the resonant cavity, achieving effective excitation of the acoustic wave mode that cannot be excited in the traditional structure.

[0102] Figure 14-16 The following are the comparison diagrams of the admittance response of the prior art structure and the structure of the present application when the wavelength of the sound wave is adjusted to 1.2 μm, 1.6 μm and 1.8 μm respectively, and the thickness of the piezoelectric layer 23 remains unchanged. Figure 1 The structure corresponds to the structure. The difference between comparative examples 2, 3 and 4 and comparative example 1 is only the period of the interdigital electrode 22. Similarly, the difference between examples 2, 3 and 4 and example 1 is only the period of the interdigital electrode 22 and the material of the impedance control region 21. The acoustic wavelengths of examples 2, 3 and 4 are 1.2 μm, 1.6 μm and 1.8 μm respectively, and the material of the impedance control region 21 is SiO2. Figure 8 The structure corresponds to the structure. Obviously, through Figure 14-16 It can be seen that when the wavelength of the acoustic wave changes, by adjusting the thickness of the impedance control region 21, the pseudo mode can still be effectively eliminated, and a pure main mode resonance response can be obtained. The corresponding filter can obtain an ideal response with flat passband, steep band edge and high out-of-band suppression, showing strong applicability and practicality. When λ is 1.2μm, the resonant frequency can reach above 5.0GHz, which helps to increase the operating frequency while maintaining the interdigital line width and expand the application of high frequency.

[0103] In Example 1, the material of the impedance control region 21 can be aluminum nitride AlN, silicon nitride Si3N4, gallium nitride GaN and other materials, all of which have high thermal conductivity and large elastic coefficient, which help to improve the temperature stability of the device; the material of the impedance control region 21 can also be silicon oxide SiO2, which has a positive frequency temperature coefficient and can thus bring about a significant frequency temperature compensation effect. Figure 17-19 They are the simulated admittance curves of the structure of Example 1 under different impedance control zone materials. Fig. 20 Figures (a)-(c) in the figure are Figure 17-19 Among them, comparative examples 5, 6 and 7 are no different from comparative example 1, that is, the structures of comparative examples 5, 6 and 7 are the same as Figure 1As shown, the period of the interdigitated electrodes 22 is 1.4 μm. Similarly, the period of the interdigitated electrodes 22 of Examples 5, 6 and 7 is 1.4 μm. The difference between Examples 5, 6 and 7 and Example 1 is only the material of the impedance control region 21, wherein the material of the impedance control region 21 corresponding to Example 5 is Si3N4, the material of the impedance control region 21 corresponding to Example 6 is GaN, and the material of the impedance control region 21 corresponding to Example 7 is SiO2. Figure 17-20 It can be seen that examples 5-7 all exhibit the same vibration mode as example 1 (see Fig.10 ), indicating that the acoustic wave modes at this time are all quasi-high-order Lamb wave modes. Compared with the main mode excited in the traditional structure, the electromechanical coupling coefficient and the speed of sound are improved (among which, the 7.94%, 7.73% and 7.88% respectively). In summary, the following Figure 8 The acoustic wave resonator shown can excite a quasi-high-order Lamb wave mode with no pseudo-mode noise, high sound velocity, and large bandwidth, which is conducive to expanding applications for higher frequencies and can effectively improve the heat dissipation performance and temperature stability of the device.

[0104] The existence of pseudo-modes of longitudinal leakage wave modes in rotated YX-cut piezoelectric single crystals, see Figure 21-22 , which are respectively the simulated admittance curves corresponding to the piezoelectric layer being lithium tantalate cut by rotating YX24° and lithium tantalate cut by rotating YX60°. Specifically, the difference between Example 8, Example 9 and Example 1 is only the material of the piezoelectric layer 23. Specifically, the piezoelectric layer 23 of Example 8 is lithium tantalate cut by rotating YX24°, and the material of the piezoelectric layer 23 of Example 9 is lithium tantalate cut by rotating YX60°. The difference between Example 8, Example 9 and Example 1 is only the material of the piezoelectric layer 23. Specifically, the piezoelectric layer 23 of Example 8 is lithium tantalate cut by rotating YX24°, and the material of the piezoelectric layer 23 of Example 9 is lithium tantalate cut by rotating YX60°, and the material of the impedance control region 21 of both is SiO2. From Figure 21-22 It can be seen that for the rotational YX-cut piezoelectric single crystal, as long as the present application is adopted Figure 8 The structures shown can all obtain pure quasi-high-order Lamb wave mode excitation, indicating that this structure is a practical solution for obtaining pure high-frequency resonators.

[0105] Further, when the supporting substrate 1 material of the resonator is changed to 6H-SiC, comparative examples 10 and 11 (except for the supporting substrate 1 material, the acoustic wave wavelength and the material of the impedance control region 21, the other structural parameters are the same as those of comparative example 1), examples 10 and 11 (except for the supporting substrate 1 material, the acoustic wave wavelength and the material of the impedance control region 21, the other structural parameters are the same as those of example 1), the supporting substrate 1 material of the resonators of these four structures is 6H-SiC, and the material of the impedance control region 21 is SiO2, wherein the acoustic wave wavelengths corresponding to comparative examples 10 and example 10 are both 1.2 μm, and the acoustic wave wavelengths corresponding to comparative examples 11 and example 11 are both 1.4 μm, please refer to Figure 23-24 , respectively illustrate the simulated admittance curves of comparative example 10, comparative example 11, example 10 and example 11. It can be seen that the quasi-high-order Lamb wave modes of example 10 and example 11 are effectively excited, and the sound velocity and resonant frequency are improved compared with the main mode excited in the traditional structure (comparative example 10 and comparative example 11). Since the body wave sound velocity of 6H-SiC is higher than that of 4H-SiC, a higher resonant frequency can be obtained, and 6H-SiC also has high thermal conductivity and high elastic coefficient, which can effectively improve the high temperature stability of the device.

[0106] See also Fig.25 , which is a schematic diagram of the structure of the second acoustic wave resonator exemplified in the present application. The second acoustic wave resonator includes a supporting substrate 1, a piezoelectric layer 23, a forked electrode 22, and an impedance control region 21 completely covering the forked electrode 22, which are arranged in sequence from bottom to top. Fig.26 The resonator may further include a functional layer 3; the functional layer 3 is located on the impedance control region 21, wherein the functional layer 3 is used to help dissipate heat and increase the sound velocity. The materials of the impedance control region 21 and the functional layer 3 may be the same or different. An example 12 is provided, the structure of the example 12 is as follows Fig.25 As shown, in Example 12, the interdigitated electrode 22 is a metal aluminum electrode with a thickness of 100nm; the piezoelectric layer 23 is a rotated YX42° LiTaO3 with a thickness of 400nm; the supporting substrate 1 is 4H-SiC, and the acoustic wavelength of the device is 1.4μm. When the material of the impedance control region 21 is SiO2 with a thickness of 125nm, the comparison of the simulated admittance curves of Example 12 and Comparative Example 1 is shown in FIG. Fig. 27 ,and Fig. 27 The acoustic mode vibration shape corresponding to the main resonance peak of Example 12 is as follows Fig.28 As shown, the distribution of the x, y and z components of the acoustic mode in the thickness direction is shown in Fig.29 As shown. Fig. 27 It can be seen that when the second resonator proposed by the present invention is used, only one main resonance peak is excited, the pseudo mode no longer exists, and a pure mode excitation can be obtained. Fig.28 and Fig.29 According to the vibration mode and the distribution of the acoustic wave components in the thickness direction, it can be judged that the acoustic wave mode corresponding to the main resonance peak is a quasi-longitudinal leakage wave mode, whose sound velocity is about 6100m / s, and the resonance frequency is slightly higher than the main mode frequency excited in the traditional structure; in addition, the electromechanical coupling coefficient of the mode at this time is 7.71%, slightly larger than the main mode excited in the traditional structure. (7.22%), which is also conducive to obtaining higher frequency and larger bandwidth applications. On the other hand, SiO2 has a positive frequency temperature coefficient, which can bring about a significant frequency temperature compensation effect, reduce the frequency temperature drift of the device, and improve the temperature stability of the device. This example also shows that SiO2 is used as the impedance control area 21, and the acoustic impedance matching between the covered area and the uncovered area of ​​the forked electrode 22 is adjusted to achieve the mode fusion of the main mode and the pseudo mode with the longitudinal leakage wave as the target acoustic wave mode. The sound velocity of this quasi-longitudinal leakage wave mode is between the main mode and the pseudo mode, and the electromechanical coupling coefficient is greater than the main mode and less than the sum of the main mode and the pseudo mode. Only one main resonance peak is excited, showing good mode fusion, suppressing pseudo mode spurious response, obtaining a pure high-frequency resonance response, and increasing the resonance frequency and electromechanical coupling coefficient.

[0107] In the second resonator, when a functional layer 3 is formed on the impedance control region 21, the material of the functional layer 3 can be aluminum nitride AlN, silicon nitride Si3N4, gallium nitride GaN and other materials. On the one hand, the impedance control region 21 can be used to achieve frequency temperature coefficient compensation of the resonator. On the other hand, the materials of the functional layer 3 have high thermal conductivity and a large elastic coefficient, which helps to improve the heat dissipation performance of the device, quickly dissipate heat, reduce the operating temperature rise of the device, and help improve the temperature stability of the device. Provide comparative example 1, example 13 and example 14 (except for the newly added functional layer 3, the other structural parameters are the same as example 12), wherein in example 13, the material of the functional layer 3 is AlN, and in example 14, the material of the functional layer 3 is Si3N4. For details of the comparison of the admittance response of comparative example 1, example 13 and example 14, see Figure 30-31 , the vibration modes corresponding to the main mode resonances of Examples 13 and 14 are as follows Fig.32 The distribution of the x, y and z components of the acoustic mode in the thickness direction is shown in Fig.33 As shown in the figure, the acoustic wave mode at this time is a quasi-longitudinal leakage wave mode, and it is still a pure mode excitation. Therefore, the second resonator structure can also excite a quasi-longitudinal leakage wave mode with no pseudo-mode noise, high sound velocity, and large bandwidth, which is conducive to expanding applications for higher frequencies and can effectively improve the frequency temperature drift, temperature stability, and heat dissipation performance of the device. Please refer to Fig.34For the existing acoustic wave resonator, since area 1 and area 2 are covered by the interdigital electrode 22 or not, the equivalent impedance Z of the two areas is different, that is, Z1≠Z2, and the sound speed of the high-frequency quasi-longitudinal leakage wave excited in different areas is different, which is then split into two resonance peaks in the admittance response. Please refer to Fig.35 When the same impedance control material with different thicknesses (h1≠h2) is covered on the surface of the interdigital electrode 22 and the piezoelectric layer 23, the equivalent impedance of region 1 and region 2 is equal (Z0=Z0), so that the excited target mode and pseudo-mode sound speed are consistent, achieving mode fusion and successfully exciting high-frequency quasi-longitudinal leakage waves without spurious modes.

[0108] See also Fig.36 , which is a schematic diagram of the structure of the fourth acoustic wave resonator of the present application. The fourth acoustic wave resonator includes a supporting substrate 1, an interdigitated electrode 22 and a piezoelectric layer 23 arranged in sequence from bottom to top. The piezoelectric layer 23 here serves as both a piezoelectric layer 23 and an impedance control region 21. Fig.37 The fifth acoustic wave resonator structure is provided, and the resonator may further include a functional layer 3; the functional layer 3 is located on the impedance control area 21, wherein the functional layer 3 is used to help dissipate heat and increase the sound speed. Example 15, Example 16 and Example 17 are provided, and the structure of Example 15 is as follows Fig.36 As shown, in Example 15, the interdigitated electrode 22 is a metal aluminum electrode with a thickness of 150nm; the piezoelectric layer 23 is a rotated YX42° Li TaO3 with a thickness of 400nm; the supporting substrate 1 is 4H-SiC, and the acoustic wavelength of the device is 1.4μm. The structures of Examples 16 and 17 are as shown Fig.37 As shown, the difference between the two and Example 15 is that they also include a functional layer 3, and the rest of the structure is the same as Example 15, wherein the material of the functional layer 3 of Example 16 is AlN, and the material of the functional layer 3 of Example 17 is SiO2. The admittance response of Comparative Example 1 is compared with Examples 15, 16 and 17 respectively as shown Figure 38-40 , and the acoustic wave mode vibration shapes corresponding to the main resonance peaks of Examples 15-17 are respectively as follows Fig.41 From Figures (a), (b) and (c), it can be seen that when the fourth and fifth resonators proposed in the present invention are used, when the piezoelectric layer 23 is covered on the interdigital electrode 22, the longitudinal electric field component generated in the piezoelectric layer 23 becomes weaker, so only the target mode is excited, and the stray mode near the anti-resonance frequency of the target mode is no longer excited, and pure mode excitation can be obtained, and the sound wave speed and the resonant frequency are significantly improved. However, since the excitation source interdigital electrode 22 is located at the bottom of the piezoelectric layer 23 and the surface of the supporting substrate 1, the electromechanical coupling coefficient of the target acoustic wave mode is slightly sacrificed, from 7.22% to 6.11%~6.44%.

[0109] In the case where the impedance control region 21 covers the blank area of ​​the layer where the interdigital electrodes 22 are located, the following two types of acoustic wave resonators may be included, as shown in the following examples for details.

[0110] See also Fig.42 , which is a schematic diagram of the structure of the sixth acoustic wave resonator of the present application. The sixth acoustic wave resonator includes a supporting substrate 1, a piezoelectric layer 23 and an interdigital electrode 22 arranged in sequence from bottom to top, and the impedance control region 21 is located in a blank area of ​​the layer where the interdigital electrode 22 is located, such as the spacing area between the electrode fingers of the interdigital electrode 22. When the thickness of the impedance control region 21 is greater than the thickness of the interdigital electrode 22, the structure of the acoustic wave resonator is as follows Fig.42 As shown, when the thickness of the impedance control region 21 is less than the thickness of the interdigital electrode 22, the structure of the acoustic wave resonator is as follows: Fig.43 As shown, it is a schematic diagram of the structure of the seventh acoustic wave resonator of the present application, wherein the thickness of the impedance control region 21 is determined by the material type of the impedance control region 21 and the matching of the metal material type and thickness. The acoustic impedance is matched by the different thicknesses of the impedance control region 21 in the area covered by the interdigital electrode 22 and the area not covered, and the mode fusion of the main mode and the pseudo mode is achieved with the longitudinal leakage wave as the target acoustic wave mode. An example 18 is provided, and the structure of the example 18 is as follows Fig.42 As shown, in Example 18, the interdigitated electrode 22 is a metal aluminum electrode with a thickness of 100nm; the piezoelectric layer 23 is a rotated YX42° Li TaO3 with a thickness of 400nm; the supporting substrate 1 is 4H-Si C, and the acoustic wavelength of the device is 1.4μm. When the material of the impedance control region 21 is SiO2 with a thickness of 110nm, the admittance response of Example 18 is compared with that of Comparative Example 1. Fig.44 ,and Fig.42 The acoustic mode vibration shape corresponding to the main resonance peak of Example 18 is as follows Fig.45 As shown, the distribution of the x, y and z components of the acoustic mode in the thickness direction is shown in Fig.46 As shown. It can be seen that when the sixth resonator is used, only one main resonance peak is excited, the pseudo mode no longer exists, and pure mode excitation can be obtained. Fig.45 and Fig.46 According to the vibration mode and the distribution of the acoustic wave components in the thickness direction, it can be judged that the acoustic wave mode corresponding to the main resonance peak is a quasi-longitudinal leakage wave mode, whose sound velocity is about 6120m / s, and the resonance frequency is slightly higher than the main mode frequency excited in the traditional structure; in addition, the electromechanical coupling coefficient is 7.91%, slightly larger than the main mode excited in the traditional structure. (7.22%), which is also conducive to obtaining higher frequency and larger bandwidth applications. Similar to the second acoustic wave resonator mentioned above, the quasi-longitudinal leakage wave mode excited at this time also has a sound velocity between the main mode and the pseudo mode, showing good mode fusion, suppressing the pseudo mode spurious response, obtaining pure high-frequency resonance, and increasing the resonance frequency and electromechanical coupling coefficient.

[0111] The material of the impedance control region 21 can be aluminum nitride AlN, silicon nitride Si3N4, gallium nitride GaN and other materials. Examples 19, 20 and 21 are provided (except for the material and thickness of the impedance control region 21, the other structural parameters are the same as those of Example 18), wherein the material of the impedance control region 21 in Example 19 is AlN, the material of the impedance control region 21 in Example 20 is Si3N4, the material of the impedance control region 21 in Example 21 is GaN, and the height of the impedance control region 21 in Examples 19-21 is lower than the interdigital electrode 22 (that is, the thickness of the impedance control region 21 is less than the thickness of the interdigital electrode 22), and the admittance response comparison of Example 1, Example 19, Example 20 and Example 21 is as follows: Figures 47-49 The vibration modes corresponding to the main mode resonances of Examples 19, 20 and 21 are as follows: Fig.50 The distribution of the x, y and z components of the acoustic mode in the thickness direction is shown in Fig.51 As shown, according to the vibration mode and the distribution of the acoustic wave components in the thickness direction, it can be judged that the acoustic wave mode corresponding to the main resonance peak is still the quasi-longitudinal leakage wave mode, and its sound velocity is about 6120m / s, and the resonance frequency is slightly higher than the main mode frequency excited in the traditional structure; in addition, the electromechanical coupling coefficients of Example 19, Example 20 and Example 21 are 7.63%, 7.64% and 7.67% respectively, which are slightly larger than the main mode frequency excited in the traditional structure. (7.22%), which is also conducive to obtaining higher frequency and larger bandwidth applications. Figure 52-53 When the same impedance control material of different thicknesses (h1≠h2) is covered between the interdigitated electrodes 22, that is, the surface of the piezoelectric layer 23, the equivalent impedance of region 1 and region 2 is equal (Z1'=Z2'), so that the excited target mode and pseudo-mode sound speed are consistent, achieving mode fusion and successfully exciting high-frequency quasi-longitudinal leakage waves without spurious modes.

[0112] In general, the above seven acoustic wave resonators proposed in this application can effectively excite quasi-high-order Lamb waves and / or quasi-longitudinal leakage wave modes with no pseudo-mode clutter, high sound velocity, and large bandwidth, which is conducive to expanding applications for higher frequencies and large bandwidths, and can effectively improve the heat dissipation performance and temperature stability of the device, and solve the compatibility problem between high frequency and interdigital line width. Specifically, through the reasonable design of the material and thickness of the impedance control area 21 (such as covering the impedance control area 21 of different thicknesses on the surface of the interdigital electrode 22 and the piezoelectric layer 23 at the same time, or burying the electrode inside the piezoelectric layer 23), the acoustic impedance of the material structure is regulated, and the distribution of the acoustic wave component in the thickness direction of the structure is regulated to reduce the leakage of the target high sound velocity mode in the thickness direction, thereby effectively constraining the energy of the target acoustic wave mode, and being able to excite the high sound velocity acoustic wave mode without pseudo-modes, and achieve a pure high-frequency resonant response. In addition, the impedance control area 21 can be covered to different surface areas (such as only the piezoelectric surface between the electrode fingers covers the impedance control area 21), and the impedance matching between the covered area and the uncovered area of ​​the forked electrode 22 is adjusted, and the equivalent impedance of the resonant area covered by the forked electrode 22 and the resonant area not covered by the electrode is adjusted to be consistent, so that the equivalent sound velocity of the target mode and the accompanying stray mode is adjusted to be the same, and mode fusion occurs (such as the main mode and pseudo mode that are excited at the same time and have close but unequal frequencies), forming a sound wave mode, thereby suppressing the pseudo mode stray response of the target sound wave mode, obtaining a pure high-frequency resonant response, and improving the resonant frequency and electromechanical coupling coefficient. While maintaining the line width of the forked electrode 22 to meet the mass production requirements, a higher frequency and larger bandwidth response can be achieved, and the corresponding filter passband is flat, the band edge is steep, and the out-of-band suppression is high. In addition, through the design of the impedance control area 21, the impedance matching layer with high thermal conductivity, large elastic coefficient and positive frequency temperature coefficient can also improve the heat dissipation performance and frequency temperature drift of the device at the same time, and improve the temperature stability and power tolerance of the device.

[0113] On the other hand, the present application discloses 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.

[0114] 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 acoustic wave resonator, characterized in that: include: a supporting substrate; A resonant cavity structure, the resonant cavity structure is located on the supporting substrate, and the resonant cavity structure includes an impedance control region and interdigital electrodes; By regulating the structural parameters and performance parameters of the impedance control zone, combined with the mass loading effect, the distribution of the acoustic wave component in the thickness direction of the acoustic wave resonator can be adjusted, and the impedance matching between the area covered by the interdigital electrodes and the area not covered by the interdigital electrodes can be regulated; the target mode of the acoustic wave resonator is generated by the electric field excitation in the direction of acoustic wave propagation and / or the thickness direction of the acoustic wave resonator; The resonant cavity structure also includes a piezoelectric layer; the interdigitated electrodes are arranged on the supporting substrate, the piezoelectric layer covers the interdigitated electrodes, the piezoelectric layer is the impedance control zone, and the material of the impedance control zone is a piezoelectric material, or the piezoelectric layer is arranged on the supporting substrate, the interdigitated electrodes are arranged on the piezoelectric layer, and the impedance control zone is arranged on the blank area of ​​the interdigitated electrodes and / or the piezoelectric layer; the blank area includes the spacing area between the electrode fingers of the interdigitated electrodes.

2. The acoustic wave resonator according to claim 1, characterized in that It also includes functional layers; The functional layer is located on the impedance control region.

3. The acoustic wave resonator according to claim 1, characterized in that The performance parameters of the impedance control region include the material of the impedance control region; The structural parameters of the impedance control region include the position and size of the impedance control region.

4. The acoustic wave resonator according to claim 1, characterized in that The material of the impedance control region includes at least one of aluminum nitride, silicon nitride, gallium nitride, silicon oxide, silicon carbide, diamond, diamond-like carbon, sapphire, magnesium oxide, aluminum oxide, silicon, boron carbide, boron nitride, lithium tantalate, lithium niobate and potassium niobate; When the period of the interdigital electrodes is equal to the wavelength λ of the acoustic wave, the thickness of the impedance control region ranges from 0.01λ to 0.15λ.

5. The acoustic wave resonator according to claim 1, characterized in that The slow shear wave velocity of the support substrate is greater than or equal to 5500 m / s; The support substrate material includes at least one of silicon carbide, diamond, diamond-like carbon, silicon, sapphire, gallium nitride, boron carbide, boron nitride and aluminum nitride.

6. The acoustic wave resonator according to claim 1, characterized in that The target acoustic wave modes include quasi-longitudinal leakage waves, quasi-high-order shear waves, or quasi-high-order Lamb waves; The product of the wavelength of the acoustic wave and the resonant frequency of the target acoustic wave mode is greater than 65% of the slow shear wave sound velocity of the support substrate and is less than the slow shear wave sound velocity of the support substrate.

7. The acoustic wave resonator according to claim 1, characterized in that The piezoelectric layer material includes lithium tantalate, lithium niobate or potassium niobate; When the period of the interdigital electrodes is equal to the wavelength λ of the acoustic wave, the thickness of the piezoelectric layer is in the range of 0.15λ to 0.4λ.

8. The acoustic wave resonator according to claim 2, characterized in that The acoustic wave energy of the target mode is concentrated in the resonant cavity structure; The thermal conductivity of the functional layer is greater than the thermal conductivity of the piezoelectric layer, and the sound velocity of the functional layer is greater than the body wave sound velocity of the piezoelectric layer; The material of the functional layer includes at least one of aluminum nitride, silicon nitride, gallium nitride, silicon carbide, diamond, diamond-like carbon, sapphire, magnesium oxide, aluminum oxide, silicon, boron carbide, boron nitride, lithium tantalate, lithium niobate and potassium niobate; When the period of the interdigital electrodes is equal to the wavelength λ of the acoustic wave, the thickness of the functional layer ranges from 0.015λ to 0.15λ.

9. A communication device, characterized in that: comprising an acoustic wave resonator as claimed in any one of claims 1 to 8; The communication device includes at least one of a filter, a duplexer and a multiplexer.

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