A sound wave resonator and electronic equipment

Abstract

The present application provides an acoustic wave resonator and an electronic device, and relates to the technical field of acoustic wave resonators. In the acoustic wave resonator provided by the present application, the longitudinal main acoustic wave mode and the shear stray acoustic wave mode are both dispersive waves. Therefore, by designing the thickness of the piezoelectric layer and the ratio of the periodic wavelength of the forked electrode, the dispersion characteristics of the longitudinal main acoustic wave mode and the shear stray acoustic wave mode are regulated, so that the dispersion curves of the longitudinal main acoustic wave mode and the shear stray acoustic wave mode intersect, so as to achieve the purpose of adjusting the longitudinal main acoustic wave mode and the shear stray acoustic wave mode to a similar resonant frequency, thereby achieving effective suppression of the stray acoustic wave mode and improving the efficiency of the mutual conversion of the main acoustic wave mode electrical energy and mechanical energy. The technical solution provided by the present application breaks through the existing method of suppressing the shear stray acoustic wave mode by thinning the thickness of the piezoelectric layer, and provides a new idea for the suppression of stray acoustic wave modes in the field of resonators.

Description

Technical Field

[0001] The present application relates to the technical field of acoustic wave resonators, and more specifically, to an acoustic wave resonator and an electronic device. Background Art

[0002] Among various RF filters, acoustic wave filters have long been a key component in communication systems, with advantages such as small size, low cost, and high stability. Acoustic wave filters are usually built from acoustic wave resonators, so the demand for high-performance acoustic wave filters is essentially the demand for high-performance acoustic wave resonators. Although existing acoustic wave resonators have achieved a good waveguide effect, they also enhance high-order acoustic wave modes, which may cause some stray acoustic wave modes to appear near the resonant frequency of the main acoustic wave mode. Summary of the invention

[0003] In view of this, the present application provides an acoustic wave resonator and an electronic device, which effectively solve the technical problems existing in the prior art, adjust the longitudinal main acoustic wave mode and the shear stray acoustic wave mode to similar resonant frequencies, not only effectively suppress the stray acoustic wave mode, but also integrate it into the main acoustic wave mode, thereby improving the efficiency of the mutual conversion between electrical energy and mechanical energy of the main acoustic wave mode.

[0004] To achieve the above objectives, the technical solutions provided by this application are as follows:

[0005] An acoustic wave resonator, the acoustic wave resonator comprising:

[0006] substrate;

[0007] A piezoelectric layer disposed on a surface of one side of the substrate;

[0008] An interdigitated electrode is disposed on a surface of the piezoelectric layer facing away from the substrate, the interdigitated electrode comprises first finger electrodes and second finger electrodes alternately arranged at intervals, and the length extension direction of the first finger electrodes and the second finger electrodes is the same;

[0009] The tangent direction of the piezoelectric material of the piezoelectric layer is a set tangent direction, the in-plane Euler angle of the piezoelectric layer is a set angle, and the ratio of the thickness of the piezoelectric layer to the periodic wavelength of the interdigitated electrode is a set ratio, so that the difference in resonant frequency of two acoustic wave modes affected by at least two different piezoelectric coefficients is within an allowable range, wherein the at least two different piezoelectric coefficients include at least one longitudinal piezoelectric coefficient and at least one shear piezoelectric coefficient, and the two acoustic wave modes include a longitudinal main acoustic wave mode and a shear stray acoustic wave mode.

[0010] Optionally, the piezoelectric material of the piezoelectric layer is lithium niobate, the set tangent direction is the X tangent direction, and the in-plane Euler angle is the angle between the direction perpendicular to the length extension direction and the +Y axis direction in the coordinate system of the X tangent direction.

[0011] Optionally, the in-plane Euler angle of the piezoelectric layer ranges from greater than or equal to 10° to less than or equal to 80° or greater than or equal to -170° to less than or equal to -100°.

[0012] Optionally, the ratio of the thickness of the piezoelectric layer to the periodic wavelength of the interdigital electrodes is in a range of greater than or equal to 0.1 and less than or equal to 0.9.

[0013] Optionally, the longitudinal main acoustic wave mode is a zero-order longitudinal acoustic wave mode, and the shear stray acoustic wave mode is a high-order shear acoustic wave mode.

[0014] Optionally, the substrate is any one of a silicon carbide substrate, a sapphire substrate, a gallium nitride substrate, a silicon substrate and a composite substrate;

[0015] The composite substrate is formed by stacking at least two sub-substrate layers, the material of at least one of the sub-substrate layers is different from that of the other sub-substrate layers, and the material of the sub-substrate layer is any one of silicon carbide, sapphire, polysilicon, silicon and silicon dioxide.

[0016] Optionally, the piezoelectric layer is any one of a lithium niobate layer, a lithium tantalate layer and a composite piezoelectric layer;

[0017] The composite piezoelectric layer is formed by stacking at least two sub-piezoelectric layers, the material of at least one of the sub-piezoelectric layers is different from the material of the other sub-piezoelectric layers, and the sub-piezoelectric layer is any one of a lithium niobate layer, an aluminum nitride layer, a scandium-doped aluminum nitride layer, a lithium tantalate layer and a zinc oxide layer; the thickness range of the piezoelectric layer is greater than or equal to 10nm and less than or equal to 5000nm.

[0018] Optionally, a material of any one of the first finger electrode and the second finger electrode is any one of aluminum, copper, platinum, gold, silver, tungsten, molybdenum, chromium, nickel, titanium-gold alloy, titanium-aluminum alloy, chromium-gold alloy and chromium-aluminum alloy.

[0019] Optionally, the number of any one of the first finger electrodes and the second finger electrodes is greater than or equal to 2 and less than or equal to 500;

[0020] The thickness of the finger electrode is in the range of greater than or equal to 5 nm and less than or equal to 500 nm;

[0021] The width of the finger electrode is greater than or equal to 0.001 μm and less than or equal to 5 μm;

[0022] The length of the finger electrode is in the range of greater than or equal to 1 μm and less than or equal to 500 μm.

[0023] Based on the same inventive concept, the present application also provides an electronic device, which includes the above-mentioned acoustic wave resonator.

[0024] Compared with the prior art, the technical solution provided by this application has at least the following advantages:

[0025] The present application provides an acoustic wave resonator and an electronic device, the acoustic wave resonator comprising: a substrate; a piezoelectric layer arranged on one surface of the substrate; interdigitated electrodes arranged on the surface of the piezoelectric layer away from the substrate, the interdigitated electrodes comprising a first finger electrode and a second finger electrode arranged alternately at intervals, the length extension direction of the first finger electrode and the second finger electrode being the same; the tangent direction of the piezoelectric material of the piezoelectric layer is a set tangent direction, the in-plane Euler angle of the piezoelectric layer is a set angle, the ratio of the thickness of the piezoelectric layer to the periodic wavelength of the interdigitated electrodes is a set ratio, so that the difference in resonant frequency of two acoustic wave modes acted by at least two different piezoelectric coefficients is within an allowable range, wherein the at least two different piezoelectric coefficients include at least one longitudinal piezoelectric coefficient and at least one shear piezoelectric coefficient, and the two acoustic wave modes include a longitudinal main acoustic wave mode and a shear stray acoustic wave mode.

[0026] It can be seen from the above content that in the acoustic resonator provided by the present application, the longitudinal main acoustic wave mode and the shear stray acoustic wave mode are both dispersive waves. Therefore, by designing the thickness of the piezoelectric layer and the ratio of the periodic wavelength of the forked electrode, the dispersion characteristics of the longitudinal main acoustic wave mode and the shear stray acoustic wave mode are regulated, so that the dispersion curves of the longitudinal main acoustic wave mode and the shear stray acoustic wave mode intersect, so as to achieve the purpose of adjusting the longitudinal main acoustic wave mode and the shear stray acoustic wave mode to a similar resonant frequency, which not only achieves effective suppression of the stray acoustic wave mode, but also integrates it into the main acoustic wave mode, thereby improving the efficiency of the mutual conversion of electrical energy and mechanical energy in the main acoustic wave mode. The technical solution provided by the present application breaks through the existing method of suppressing the shear stray acoustic wave mode by thinning the thickness of the piezoelectric layer, achieves the purpose of suppressing the stray acoustic wave mode and improving the electromechanical coupling coefficient, and provides a new idea for the suppression of stray acoustic wave modes in the field of resonators. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0028] Figure 1 A schematic diagram of the structure of an acoustic wave resonator provided in an embodiment of the present application;

[0029] Figure 2 A three-dimensional schematic diagram of an inner Euler angle rotation in the X-tangent direction provided in an embodiment of the present application;

[0030] Figure 3 A schematic diagram of the structure of another acoustic wave resonator provided in an embodiment of the present application;

[0031] Figure 4 A schematic diagram of polarization displacement provided in an embodiment of the present application;

[0032] Figure 5 Another schematic diagram of polarization displacement provided in an embodiment of the present application;

[0033] Figure 6 A simulated admittance curve diagram provided in an embodiment of the present application;

[0034] Figure 7 Another simulated admittance curve diagram provided in an embodiment of the present application;

[0035] Figure 8 Another simulated admittance curve diagram provided in an embodiment of the present application;

[0036] Fig. 9 Another simulated admittance curve diagram provided in an embodiment of the present application;

[0037] Fig.10 Another simulated admittance curve diagram provided in an embodiment of the present application;

[0038] Fig.11 Another simulated admittance curve diagram provided in an embodiment of the present application. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions 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.

[0040] As mentioned in the background technology, Enhanced Mobile Broadband (eMBB), Massive Machine Type of Communication (mMTC) and UltraReliable Low Latency Communications (uRLLC) are the three major application scenarios of 5G. Among them, enhanced mobile broadband is one of the important application scenarios of 5G, which aims to meet the growing demand of users for high-speed data, such as ultra-high-definition video, virtual reality (VR) and augmented reality (AR). However, these put forward high requirements on the radio frequency (RF) signal processing capabilities of smart devices. On the one hand, the physical bandwidth of the new frequency band in 5G New Radio (NR) has been significantly improved; on the other hand, carrier aggregation (CA) technology still plays an important role in making full use of the spectrum. Therefore, RF filters need to have larger bandwidth, lower insertion loss and excellent out-of-band (OoB) suppression performance to improve signal sensitivity and eliminate out-of-band responses to avoid mutual interference with other CA communication channels.

[0041] Among various RF filters, acoustic wave filters have long been a key component in communication systems, with the advantages of small size, low cost, and high stability. Acoustic wave filters are usually built with acoustic wave resonators, so the demand for high-performance acoustic wave filters is essentially the demand for high-performance acoustic wave resonators. In recent years, the emerging piezoelectric on insulator (POI) heterogeneous substrates are very suitable for broadband acoustic wave resonator applications, especially surface acoustic wave (SAW) resonators, which have made significant progress in the manufacture of low-loss, high-performance SAW resonators with large bandwidth. Generally, POI heterogeneous substrates are composed of piezoelectric film and high-speed substrate (such as Si, sapphire, SiC, etc.). Some POI heterogeneous substrates have a SiO2 interlayer between the piezoelectric film and the high-speed substrate. This multi-layer structure achieves a better waveguide effect, solves the problem of acoustic wave energy leakage to the substrate in traditional SAW devices, and significantly improves the electromechanical coupling coefficient of the main acoustic wave mode ( ).

[0042] However, the waveguide effect is a double-edged sword because it also enhances the higher order acoustic modes, which may lead to the appearance of some spurious acoustic modes near the resonant frequency of the main acoustic mode. In modern radio communication standards, these spurious acoustic modes are usually undesirable because strict out-of-band channel attenuation levels are specified in the front-end circuit to suppress the interaction and signal distortion between the relevant CA bands. Therefore, it is necessary to suppress the spurious acoustic modes on the POI heterogeneous substrate while maintaining the high resonant frequency of the main acoustic mode. It is an issue that needs to be addressed urgently.

[0043] Based on this, the embodiments of the present application provide an acoustic wave resonator and an electronic device, which effectively solve the technical problems existing in the prior art, adjust the longitudinal main acoustic wave mode and the shear stray acoustic wave mode to similar resonant frequencies, and not only achieve effective suppression of the stray acoustic wave mode, but also integrate it into the main acoustic wave mode, thereby improving the efficiency of the mutual conversion of electrical energy and mechanical energy in the main acoustic wave mode.

[0044] To achieve the above purpose, the technical solution provided in the embodiment of the present application is as follows, specifically combined with Figures 1 to 11 The technical solution provided in the embodiments of the present application is described in detail.

[0045] Combination Figure 1 and Figure 2 As shown, Figure 1 A schematic diagram of the structure of an acoustic wave resonator provided in an embodiment of the present application, Figure 2 A three-dimensional schematic diagram of the internal Euler angle rotation in the X-tangent direction provided in an embodiment of the present application. The acoustic wave resonator provided in an embodiment of the present application comprises: a substrate 1; a piezoelectric layer 2 disposed on a surface of one side of the substrate 1; and interdigitated electrodes 3 disposed on a surface of the piezoelectric layer 2 facing away from the substrate 1, wherein the interdigitated electrodes 3 comprise first finger electrodes 31 and second finger electrodes 32 arranged alternately at intervals, and the length extension direction Z1 of the first finger electrodes 31 and the second finger electrodes 32 are the same.

[0046] The tangent direction of the piezoelectric material of the piezoelectric layer 2 is a set tangent direction, and the angle of the in-plane Euler angle of the piezoelectric layer 2 is a set angle. The piezoelectric layer 2 can be any one of a lithium niobate layer, a lithium tantalate layer, and a composite piezoelectric layer; the composite piezoelectric layer is formed by stacking at least two sub-piezoelectric layers, and the material of at least one of the sub-piezoelectric layers is different from that of the other sub-piezoelectric layers, and the sub-piezoelectric layer is any one of a lithium niobate layer, an aluminum nitride layer, a scandium-doped aluminum nitride layer, a lithium tantalate layer, and a zinc oxide layer.

[0047] In some embodiments, the piezoelectric material of the piezoelectric layer 2 is lithium niobate, the set tangent direction is the X tangent direction, and the in-plane Euler angle is the angle between the direction perpendicular to the length extension direction (the length extension direction is the length extension direction of the first finger electrode 31 or the second finger electrode 32) Z1 and the +Y axis direction in the coordinate system of the X tangent direction. The in-plane Euler angle range of the piezoelectric layer 2 is greater than or equal to 10° and less than or equal to 80° or greater than or equal to -170° and less than or equal to -100°.

[0048] Specifically, the X-tangent lithium niobate provided in the embodiment of the present application has rich piezoelectric coefficients and significant anisotropy advantages. On the one hand, the rich and large piezoelectric coefficients make the acoustic wave resonator based on the lithium niobate layer 2 superior to the existing thin film body acoustic wave resonator based on aluminum nitride piezoelectric material in terms of the important performance of the electromechanical coupling coefficient. On the other hand, in order to solve the problem of low operating frequency of the traditional zero-order shear mode surface acoustic wave resonator, it is necessary to select a longitudinal acoustic wave mode with a higher acoustic wave propagation speed to increase the operating frequency. The relationship between the acoustic wave propagation speed and the operating frequency can be expressed as: f = v / λ ,in, f is the operating frequency, v is the speed of sound wave propagation, λ is the periodic wavelength of the interdigital electrode. Since X-tangent lithium niobate has rich piezoelectric coefficients and significant anisotropy, by adjusting the in-plane Euler angle, the piezoelectric coefficient acting on the longitudinal acoustic wave mode can reach a high level. When the in-plane Euler angle rotates within the range of greater than or equal to 10° and less than or equal to 80° or greater than or equal to -170° and less than or equal to -100°, the longitudinal acoustic wave mode can be effectively excited.

[0049] It can be understood that the in-plane Euler angle has a period of 180°, and the entire plane is 360°, so 10° to 80° corresponds to -170° to -100° in another 180° period. In other words, the in-plane Euler angle a 1 can be the angle between the direction Y1 perpendicular to the length extension direction Z1 of the finger electrode and the +Y axis direction in the X-tangent coordinate system. At this time, the in-plane Euler angle of the piezoelectric layer 2 is a 1 is greater than or equal to 10° and less than or equal to 80°; or, the in-plane Euler angle provided in the embodiment of the present application a 2 is the angle between the direction -Y1 perpendicular to the length extension direction Z1 of the finger electrode and the +Y axis direction in the X-tangent coordinate system. At this time, the in-plane Euler angle of the piezoelectric layer 2 is a The angle range of 2 is greater than or equal to -170° and less than or equal to -100°.

[0050] Combination Figure 3 As shown, Figure 3 A schematic diagram of the structure of another acoustic wave resonator provided in an embodiment of the present application, specifically the thickness of the piezoelectric layer 2 h The periodic wavelength of the interdigital electrode 3 λ In the acoustic wave resonator provided in the embodiment of the present application, the ratio of the thickness of the piezoelectric layer 2 to the periodic wavelength of the interdigital electrode 3 is a set ratio, so that the difference in the resonant frequency of the two acoustic wave modes under the action of at least two different piezoelectric coefficients is within the allowable range, the at least two different piezoelectric coefficients include at least one longitudinal piezoelectric coefficient and at least one shear piezoelectric coefficient, and the two acoustic wave modes include a longitudinal main acoustic wave mode and a shear stray acoustic wave mode.

[0051] It can be understood that in the acoustic resonator provided by the embodiment of the present application, the longitudinal main acoustic wave mode and the shear stray acoustic wave mode are both dispersive waves. Therefore, by designing the ratio of the thickness of the piezoelectric layer 2 and the periodic wavelength of the interdigital electrode 3, the dispersion characteristics of the longitudinal main acoustic wave mode and the shear stray acoustic wave mode are regulated, so that the dispersion curves of the longitudinal main acoustic wave mode and the shear stray acoustic wave mode intersect, so as to achieve the purpose of adjusting the longitudinal main acoustic wave mode and the shear stray acoustic wave mode to a similar resonant frequency, not only achieving effective suppression of the stray acoustic wave mode, but also integrating it into the main acoustic wave mode, improving the efficiency of the mutual conversion of the main acoustic wave mode electrical energy and mechanical energy. The technical solution provided by the embodiment of the present application breaks through the existing method of suppressing the shear stray acoustic wave mode by thinning the thickness of the piezoelectric layer, achieving the purpose of suppressing the stray acoustic wave mode and improving the electromechanical coupling coefficient, and providing a new idea for the suppression of stray acoustic wave modes in the field of resonators.

[0052] Optionally, when the piezoelectric material of the piezoelectric layer 2 is lithium niobate, and the set tangent direction is the X tangent direction, it can be seen from the above description that when the in-plane Euler angle is greater than or equal to 10° and less than or equal to 80°, or the in-plane Euler angle is rotated within the range of greater than or equal to -170° and less than or equal to -100°, the longitudinal acoustic wave mode can be effectively excited. However, the rich piezoelectric coefficients of the X-tangent lithium niobate make it possible for not only the longitudinal piezoelectric coefficients but also the shear piezoelectric coefficients to act at this time. The existence of these shear piezoelectric coefficients excites some stray acoustic wave modes, among which the operating frequency of the high-order shear stray acoustic wave mode is closest to the longitudinal main acoustic wave mode. Since in the acoustic wave resonator structure proposed in the technical solution of the present invention, both the longitudinal main acoustic wave mode and the high-order shear stray acoustic wave mode are dispersive waves, their dispersion characteristics can be controlled by regulating the influence of the substrate on these two acoustic wave modes. This regulation can be achieved by designing the thickness of the piezoelectric layer. h Periodic wavelength with interdigitated electrodes λ Because the vibration shapes of these two acoustic wave modes are different, the influence of the substrate on them is also different. hPeriodic wavelength with interdigitated electrodes λ When the ratio of varies within a range of greater than or equal to 0.1 and less than or equal to 0.9, the dispersion curves of the two acoustic wave modes intersect, that is, at this time, the two acoustic wave modes have similar resonant frequencies. This not only achieves effective suppression of stray acoustic wave modes, but also integrates them into the main acoustic wave mode, thereby improving the efficiency of mutual conversion between electrical energy and mechanical energy of the main acoustic wave mode. At this time, the longitudinal main acoustic wave mode provided in the embodiment of the present application is a zero-order longitudinal acoustic wave mode, and the shear stray acoustic wave mode is a high-order shear acoustic wave mode.

[0053] Combination Figures 4 to 5 As shown, Figure 4 A schematic diagram of polarization displacement provided in an embodiment of the present application, specifically a piezoelectric material of the piezoelectric layer 2 is lithium niobate, the set tangent direction is the X tangent direction, and the thickness of the lithium niobate layer 2 is h The periodic wavelength of the interdigital electrode 3 λ Schematic diagram of the two-dimensional cross-sectional polarization displacement of the acoustic resonator under the action of the longitudinal main acoustic wave mode when the ratio is 0.5; Figure 5 Another polarization displacement schematic diagram provided in an embodiment of the present application, specifically a piezoelectric material of the piezoelectric layer 2 is lithium niobate, the set tangent direction is the X tangent direction, and the thickness of the lithium niobate layer 2 is h The periodic wavelength of the interdigital electrode 3 λ Schematic diagram of the polarization displacement of a two-dimensional section of an acoustic wave resonator under the action of a shear stray acoustic wave mode when the ratio is 0.5. It can be seen that the polarization displacement direction of the longitudinal main acoustic wave mode is the horizontal electric field direction, and the polarization displacement direction of the shear stray acoustic wave mode is the length extension direction of the middle finger electrode of the forked electrode 3. The polarization displacement directions of the two acoustic wave modes are both located in the YZ plane and are perpendicular to each other. When the dispersion curves of the two acoustic wave modes intersect, that is, the two acoustic wave modes have similar resonant frequencies, the acoustic wave resonator has the following at the resonant frequency point at the same time. Figure 4 and Figure 5 Two polarization shifts are shown.

[0054] Optionally, the substrate 1 provided in the embodiment of the present application can be any one of a silicon carbide (SiC) substrate, a sapphire (Al2O3) substrate, a gallium nitride (GaN) substrate, a silicon (Si) substrate and a composite substrate; the composite substrate is formed by stacking at least two sub-substrate layers, and the material of at least one of the sub-substrate layers is different from that of the other sub-substrate layers, and the material of the sub-substrate layer is any one of silicon carbide, sapphire, polycrystalline silicon (poly-Si), silicon and silicon dioxide (SiO2).

[0055] Furthermore, the thickness of the piezoelectric layer 2 provided in the embodiment of the present application may be in the range of greater than or equal to 10 nm and less than or equal to 5000 nm.

[0056] In addition, the material of any one of the first finger electrodes 31 and the second finger electrodes 32 provided in the embodiment of the present application is any one of aluminum, copper, platinum, gold, silver, tungsten, molybdenum, chromium, nickel, titanium-gold alloy, titanium-aluminum alloy, chromium-gold alloy and chromium-aluminum alloy. The number of any one of the first finger electrodes 31 and the second finger electrodes 32 is greater than or equal to 2 and less than or equal to 500; the thickness of the finger electrodes is greater than or equal to 5nm and less than or equal to 500nm; the width of the finger electrodes is greater than or equal to 0.001μm and less than or equal to 5μm; the length of the finger electrodes is greater than or equal to 1μm and less than or equal to 500μm.

[0057] From the above description, it can be seen that the technical solution provided by the present application is to set the tangent direction by designing the piezoelectric material of the piezoelectric layer 2, and to optimize the in-plane Euler angle of the piezoelectric layer 2 and the thickness of the piezoelectric layer 2. h and the periodic wavelength of the interdigitated electrode 3 λ The ratio of at least two different piezoelectric coefficients is used to control the dispersion characteristics of two acoustic wave modes, thereby adjusting the two acoustic wave modes to similar resonant frequencies, wherein the at least two different piezoelectric coefficients include at least one longitudinal piezoelectric coefficient and at least one shear piezoelectric coefficient, and the two acoustic wave modes include a longitudinal main acoustic wave mode and a shear stray acoustic wave mode.

[0058] When the piezoelectric material of the piezoelectric layer 2 is lithium niobate, and the set tangent direction is the X tangent direction, the in-plane Euler angle is the angle between the direction perpendicular to the length extension direction Z1 and the +Y axis direction in the coordinate system of the X tangent direction. When the in-plane Euler angle of the lithium niobate layer 2 rotates within the range of greater than or equal to 10° and less than or equal to 80° or greater than or equal to -170° and less than or equal to -100°, and the ratio of the thickness of the lithium niobate layer 2 to the periodic wavelength of the interdigital electrode 3 is greater than or equal to 0.1 and less than or equal to 0.9, the dispersion curves of the longitudinal main acoustic wave mode and the shear stray acoustic wave mode can be made to intersect, so as to achieve the purpose of adjusting the longitudinal main acoustic wave mode and the shear stray acoustic wave mode to a similar resonant frequency, which not only achieves effective suppression of the stray acoustic wave mode, but also integrates it into the main acoustic wave mode, thereby improving the efficiency of mutual conversion between the electrical energy and mechanical energy of the main acoustic wave mode.

[0059] The following uses lithium niobate with the piezoelectric layer 2 being X-tangent as an example, and combines several simulated admittance curves to describe the acoustic wave resonator provided in the embodiment of the present application in more detail. Figure 6 As shown, it is a simulated admittance curve provided in an embodiment of the present application, specifically, the thickness of a piezoelectric layer 2 h The periodic wavelength of the interdigital electrode 3 λWhen the ratio is 0.48 and the in-plane Euler angle is 40°, the acoustic resonator with the longitudinal main acoustic wave mode and the shear stray acoustic wave mode with similar resonant frequency works at a simulated admittance curve of 9.5 GHz; through calculation, its electromechanical coupling coefficient is 33%. The calculation formula of the electromechanical coupling coefficient is:

[0060]

[0061] in, f s is the series resonant frequency of the acoustic wave resonator, f p is the parallel resonant frequency of the acoustic wave resonator.

[0062] like Figure 7 As shown, another simulated admittance curve diagram provided in the embodiment of the present application is specifically a thickness of a piezoelectric layer 2 h The periodic wavelength of the interdigital electrode 3 λ When the ratio is 0.15 and the in-plane Euler angle is 40°, the acoustic resonator with the joint action of the longitudinal main acoustic wave mode and the shear stray acoustic wave mode with similar resonant frequency works at a simulated admittance curve of 4.1 GHz; its electromechanical coupling coefficient can be obtained by calculation to be 14.5%.

[0063] like Figure 8 As shown, it is another simulated admittance curve provided in the embodiment of the present application, specifically, the thickness of the piezoelectric layer 2 h The periodic wavelength of the interdigital electrode 3 λ When the ratio is 0.75 and the in-plane Euler angle is 40°, the acoustic resonator with the longitudinal main acoustic wave mode and the shear stray acoustic wave mode with similar resonant frequency works at a simulated admittance curve of 16.3 GHz. Its electromechanical coupling coefficient is 18% through calculation.

[0064] like Fig. 9 As shown, it is another simulated admittance curve provided in the embodiment of the present application, specifically, the thickness of the piezoelectric layer 2 h The periodic wavelength of the interdigital electrode 3 λ When the ratio is 0.48 and the in-plane Euler angle is 55°, the acoustic resonator with the joint action of the longitudinal main acoustic wave mode and the shear stray acoustic wave mode with similar resonant frequency works at a simulated admittance curve of 9.5 GHz. The electromechanical coupling coefficient is 26.3% through calculation.

[0065] like Fig.10 As shown, it is another simulated admittance curve provided in the embodiment of the present application, specifically, the thickness of the piezoelectric layer 2 h The periodic wavelength of the interdigital electrode 3 λWhen the ratio is 0.48 and the in-plane Euler angle is 40°, the acoustic resonator with the joint action of the longitudinal main acoustic wave mode and the shear stray acoustic wave mode with similar resonant frequency works at a simulated admittance curve of 2.8 GHz. Its electromechanical coupling coefficient is 32.9% through calculation.

[0066] like Fig.11 As shown, it is another simulated admittance curve provided in the embodiment of the present application, specifically, the thickness of the piezoelectric layer 2 h The periodic wavelength of the interdigital electrode 3 λ When the ratio is 0.5 and the in-plane Euler angle is 40°, the acoustic resonator with the joint action of the longitudinal main acoustic wave mode and the shear stray acoustic wave mode with similar resonant frequency works at a simulated admittance curve of 19.7 GHz. Its electromechanical coupling coefficient is 32.8% through calculation.

[0067] Based on the same inventive concept, an embodiment of the present application further provides an electronic device, which includes the acoustic wave resonator provided by any one of the above embodiments.

[0068] In summary, the embodiments of the present application provide an acoustic wave resonator and an electronic device, the acoustic wave resonator comprising: a substrate; a piezoelectric layer disposed on a surface of one side of the substrate; interdigitated electrodes disposed on a surface of the piezoelectric layer away from the substrate, the interdigitated electrodes comprising a first finger electrode and a second finger electrode arranged alternately at intervals, the length extension direction of the first finger electrode and the second finger electrode being the same; the tangent direction of the piezoelectric material of the piezoelectric layer is a set tangent direction, the in-plane Euler angle of the piezoelectric layer is a set angle, the ratio of the thickness of the piezoelectric layer to the periodic wavelength of the interdigitated electrodes is a set ratio, so that the difference in resonant frequency of two acoustic wave modes acted by at least two different piezoelectric coefficients is within an allowable range, wherein the at least two different piezoelectric coefficients include at least one longitudinal piezoelectric coefficient and at least one shear piezoelectric coefficient, and the two acoustic wave modes include a longitudinal main acoustic wave mode and a shear stray acoustic wave mode.

[0069] When the piezoelectric material of the piezoelectric layer 2 is lithium niobate and the set tangent is the X tangent, the in-plane Euler angle is the angle between the direction perpendicular to the length extension direction Z1 and the +Y axis direction in the coordinate system of the X tangent. When the in-plane Euler angle is set to rotate within the range of greater than or equal to 10° and less than or equal to 80° or greater than or equal to -170° and less than or equal to -100°, the longitudinal main acoustic wave mode can be effectively excited. Since the longitudinal main acoustic wave mode and the shear stray acoustic wave mode are both dispersive waves, the thickness of the piezoelectric layer 2 is set at the same time. h and the periodic wavelength of the interdigitated electrode 3 λThe ratio of varies within the range of 0.1 or more and 0.9 or less, so that the dispersion curves of the longitudinal main acoustic wave mode and the shear stray acoustic wave mode intersect, so as to achieve the purpose of adjusting the longitudinal main acoustic wave mode and the shear stray acoustic wave mode to a similar resonant frequency. Finally, the operating frequency of the acoustic wave resonator can be changed from 2 GHz to more than 20 GHz, and the electromechanical coupling coefficient ( ) remained above 6%.

[0070] It can be seen from the above content that in the acoustic resonator provided by the embodiment of the present application, the longitudinal main acoustic wave mode and the shear stray acoustic wave mode are both dispersive waves. Therefore, by designing the ratio of the thickness of the piezoelectric layer and the periodic wavelength of the interdigital electrode, the dispersion characteristics of the longitudinal main acoustic wave mode and the shear stray acoustic wave mode are regulated, so that the dispersion curves of the longitudinal main acoustic wave mode and the shear stray acoustic wave mode intersect, so as to achieve the purpose of adjusting the longitudinal main acoustic wave mode and the shear stray acoustic wave mode to a similar resonant frequency, which not only achieves effective suppression of the stray acoustic wave mode, but also integrates it into the main acoustic wave mode, and improves the efficiency of the mutual conversion of electrical energy and mechanical energy in the main acoustic wave mode. The technical solution provided by the embodiment of the present application breaks through the existing method of suppressing the shear stray acoustic wave mode by thinning the thickness of the piezoelectric layer, achieves the purpose of suppressing the stray acoustic wave mode and improving the electromechanical coupling coefficient, and provides a new idea for the suppression of stray acoustic wave modes in the field of resonators. The acoustic wave resonator provided in this application is very suitable for the carrier aggregation technology in 5G wireless communication, and can effectively avoid mutual interference between different carrier aggregation channels. In addition, the operating frequency range of the acoustic wave resonator provided in this application covers multiple centimeter wave communication frequency bands, and has high operating frequency, wide bandwidth and excellent out-of-band suppression performance, which is very suitable for application in the field of centimeter wave communication.

[0071] In the description of the embodiments of the present application, it needs to be understood that the orientation or position relationship indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0072] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the embodiments of the present application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0073] In the embodiments of the present application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0074] In the embodiments of the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0075] In the embodiments of the present application, if the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" appear, it means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples without contradiction.

[0076] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. An acoustic wave resonator, characterized in that: The acoustic wave resonator includes: substrate; A piezoelectric layer disposed on a surface of one side of the substrate; An interdigitated electrode is disposed on a surface of the piezoelectric layer facing away from the substrate, the interdigitated electrode comprises first finger electrodes and second finger electrodes alternately arranged at intervals, and the length extension direction of the first finger electrodes and the second finger electrodes is the same; The tangent direction of the piezoelectric material of the piezoelectric layer is a set tangent direction, the in-plane Euler angle of the piezoelectric layer is a set angle, and the ratio of the thickness of the piezoelectric layer to the periodic wavelength of the interdigital electrode is a set ratio, so that the difference in the resonant frequency of two acoustic wave modes under the action of at least two different piezoelectric coefficients is within an allowable range, wherein the at least two different piezoelectric coefficients include at least one longitudinal piezoelectric coefficient and at least one shear piezoelectric coefficient, and the two acoustic wave modes include a longitudinal main acoustic wave mode and a shear stray acoustic wave mode; The piezoelectric material of the piezoelectric layer is lithium niobate, the set tangent direction is the X tangent direction, and the in-plane Euler angle is the angle between the direction perpendicular to the length extension direction and the +Y axis direction in the coordinate system of the X tangent direction; The in-plane Euler angle of the piezoelectric layer is in the range of greater than or equal to 10° and less than or equal to 80° or greater than or equal to -170° and less than or equal to -100°; The ratio of the thickness of the piezoelectric layer to the periodic wavelength of the interdigital electrodes is in the range of greater than or equal to 0.1 and less than or equal to 0.9, so as to adjust the ratio of the thickness of the piezoelectric layer to the periodic wavelength of the interdigital electrodes to achieve regulation of the dispersion characteristics of the longitudinal main acoustic wave mode and the shear stray acoustic wave mode, so that the dispersion curves of the longitudinal main acoustic wave mode and the shear stray acoustic wave mode intersect, so as to achieve the purpose of adjusting the longitudinal main acoustic wave mode and the shear stray acoustic wave mode to similar resonant frequencies; The longitudinal main acoustic wave mode is a zero-order longitudinal acoustic wave mode, and the shear stray acoustic wave mode is a high-order shear acoustic wave mode.

2. The acoustic wave resonator according to claim 1, characterized in that The substrate is any one of a silicon carbide substrate, a sapphire substrate, a gallium nitride substrate, a silicon substrate and a composite substrate; The composite substrate is formed by stacking at least two sub-substrate layers, the material of at least one of the sub-substrate layers is different from that of the other sub-substrate layers, and the material of the sub-substrate layer is any one of silicon carbide, sapphire, polysilicon, silicon and silicon dioxide.

3. The acoustic wave resonator according to claim 1, characterized in that The piezoelectric layer is any one of a lithium niobate layer, a lithium tantalate layer and a composite piezoelectric layer; The composite piezoelectric layer is formed by stacking at least two sub-piezoelectric layers, the material of at least one of the sub-piezoelectric layers is different from the material of the other sub-piezoelectric layers, and the sub-piezoelectric layer is any one of a lithium niobate layer, an aluminum nitride layer, a scandium-doped aluminum nitride layer, a lithium tantalate layer and a zinc oxide layer; the thickness range of the piezoelectric layer is greater than or equal to 10nm and less than or equal to 5000nm.

4. The acoustic wave resonator according to claim 1, characterized in that The material of any one of the first finger electrode and the second finger electrode is any one of aluminum, copper, platinum, gold, silver, tungsten, molybdenum, chromium, nickel, titanium-gold alloy, titanium-aluminum alloy, chromium-gold alloy and chromium-aluminum alloy.

5. The acoustic wave resonator according to claim 1, characterized in that The number of any one of the first finger electrodes and the second finger electrodes is greater than or equal to 2 and less than or equal to 500; The thickness of the finger electrode is in the range of greater than or equal to 5 nm and less than or equal to 500 nm; The width of the finger electrode is greater than or equal to 0.001 μm and less than or equal to 5 μm; The length of the finger electrode is in the range of greater than or equal to 1 μm and less than or equal to 500 μm.

6. An electronic device, characterized in that: The electronic device comprises the acoustic wave resonator according to any one of claims 1 to 5.

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