Resonator, filter, and electronic device

Abstract

The invention provides a resonator, a filter and electronic equipment. Relates to the technical field of resonators. The resonator can improve the electromechanical coupling coefficient. The resonator comprises a substrate, a first electrode, a plurality of piezoelectric layers and a plurality of second electrodes, the first electrode, the multiple piezoelectric layers and the multiple second electrodes are arranged on the substrate, the multiple piezoelectric layers are provided with first sides and second sides, the multiple second electrodes are located on the first sides and are arranged side by side in the first direction, the first electrodes are located on the second sides, the first sides deviate from the substrate, and the second sides face the substrate; the multiple piezoelectric layers comprise a first piezoelectric layer and a second piezoelectric layer which are stacked; the piezoelectric material of the first piezoelectric layer has a first piezoelectric tensor component e34, the piezoelectric material of the second piezoelectric layer has a second piezoelectric tensor component e34, and the first piezoelectric tensor component e34 and the second piezoelectric tensor component e34 are opposite. By using the piezoelectric layer with opposite piezoelectric tensor components e34, the resonator can have large vibration so as to improve the electromechanical coupling coefficient.

Description

Technical Field

[0001] The present application relates to the technical field of resonators, and relates to a resonator, a filter, an electronic device including the filter or the resonator, and a method for manufacturing the resonator or the filter. Background Art

[0002] With the development of communication technologies, the demand for resonators in electronic devices will increase significantly. For example, bulk acoustic wave resonators such as horizontally-excited bulk acoustic resonators (XBAR), vertically-excited bulk acoustic resonators (YBAR), and film bulk acoustic resonators (FBAR) have received extensive attention.

[0003] Among them, YBAR has greater coupling and more effective resonance modes and can be applied in a larger passband bandwidth.

[0004] However, in a YBAR device, since the piezoelectric layer is attached to the substrate, the acoustic resonance vibration of the part of the piezoelectric layer close to the substrate is restricted, which suppresses the improvement of the electromechanical coupling coefficient of the resonator. Summary of the Invention

[0005] The present application provides a resonator, a filter having the resonator, an electronic device including the filter or the resonator, and a method for manufacturing the resonator. The purpose is to provide a resonator that can improve the electromechanical coupling coefficient.

[0006] To achieve the above object, the embodiments of the present application adopt the following technical solutions:

[0007] On the one hand, the present application provides a resonator. In one embodiment, the resonator may be an acoustic wave resonator, such as a YBAR.

[0008] The resonator includes: a substrate, a first electrode, a multi-layer piezoelectric layer, and a plurality of second electrodes; the first electrode, the multi-layer piezoelectric layer, and the plurality of second electrodes are disposed on the substrate, the multi-layer piezoelectric layer has a first side and a second side, the plurality of second electrodes are located on the first side and are arranged side by side in a first direction, the first electrode is located on the second side, the first side faces away from the substrate, and the second side faces the substrate; wherein, the multi-layer piezoelectric layer includes a first piezoelectric layer and a second piezoelectric layer arranged in a stacked manner; the piezoelectric material of the first piezoelectric layer has a first piezoelectric tensor component e 34 , the piezoelectric material of the second piezoelectric layer has a second piezoelectric tensor component e 34 , the first piezoelectric tensor component e 34and the second piezoelectric tensor component e 34 On the contrary, that is, the first piezoelectric tensor component e 34 and the second piezoelectric tensor component e 34 are opposite numbers to each other.

[0009] In the resonator provided by this application, the piezoelectric layer includes multiple layers. For example, it includes a stacked first piezoelectric layer and a second piezoelectric layer. The first piezoelectric tensor component e of the first piezoelectric layer 34 and the second piezoelectric tensor component e of the second piezoelectric layer 34 are opposite. Then, under the action of an electric field, the deformation directions of the first piezoelectric layer and the second piezoelectric layer are opposite. For example, when the vibration direction of the part of the first piezoelectric layer in contact with the second piezoelectric layer extends along the second electrode and vibrates away from the piezoelectric layer, the vibration direction of the part of the second piezoelectric layer in contact with the first piezoelectric layer also extends along the second electrode and vibrates away from the piezoelectric layer. These two vibrations are coupled and resonate at the position where the first piezoelectric layer and the second piezoelectric layer are in contact, so that mechanical vibrations will also be generated inside the entire piezoelectric layer, thereby improving the electromechanical coupling coefficient of the entire resonator.

[0010] In a realizable manner, the first electrode has a relative first surface and a second surface. The first surface is closer to the piezoelectric layer than the second surface, and the second surface of the first electrode is completely disposed on the substrate.

[0011] The resonator given in this example can be called a solid-state substrate resonator, and the resonator with this structure can improve the heat dissipation capacity and firmness of the device.

[0012] In a realizable manner, there is a gap between two adjacent second electrodes; there is a groove at the position of the multi-layer piezoelectric layer opposite to the gap, and the groove communicates with the gap.

[0013] Since a groove is formed in the piezoelectric layer, the groove helps to further increase the electromechanical coupling coefficient of the resonator, and can also suppress or frequency-shift parasitic modes.

[0014] In a realizable manner, for the thickness dimension H of the multi-layer piezoelectric layer and the depth dimension h of the groove, 30% H ≤ h ≤ H.

[0015] When the depth dimension of the groove is small, it will restrict the vibration of the part of the piezoelectric layer located between the first electrode and the second electrode.

[0016] In a realizable manner, the first piezoelectric layer is disposed closer to the substrate than the second piezoelectric layer; the second piezoelectric layer has a top surface away from the first piezoelectric layer, and the first piezoelectric layer has a bottom surface away from the second piezoelectric layer, and the groove penetrates the top surface and the bottom surface.

[0017] Since the groove penetrates from the top surface to the bottom surface of the piezoelectric layer, the electromechanical coupling coefficient can be further increased.

[0018] In one possible implementation, the radial dimension of the groove gradually increases from the top surface to the bottom surface.

[0019] For example, the inclination angle α of the side surface of the groove satisfies: 45° < α < 90°; or, 60° < α < 90°.

[0020] In one possible implementation, for the thickness dimension S1 of the second electrode and the thickness dimension H of the multi-layer piezoelectric layer, S1 / H ≤ 0.35.

[0021] In one possible implementation, for the thickness dimension S2 of the first electrode and the thickness dimension H of the multi-layer piezoelectric layer, S2 / H ≤ 0.35.

[0022] In some examples, in order to reduce the acoustic loss at the electrode, the thickness dimension of the first electrode or the second electrode can be reduced. However, when the thickness dimension of the electrode becomes thinner, the power tolerance of the electrode will be reduced. In the examples of this application, by increasing the thickness dimension of the piezoelectric layer and reducing the thickness ratio of the electrode relative to the piezoelectric layer, it will neither pose a challenge to the etching process nor reduce the power tolerance of the electrode.

[0023] In one possible implementation, the resonator further includes: a first bus bar and a second bus bar; among every two adjacent second electrodes in the plurality of second electrodes, one is a first interdigital electrode and the other is a second interdigital electrode; the first interdigital electrode and the second interdigital electrode are spaced apart in a first direction; the plurality of first interdigital electrodes among the plurality of second electrodes are connected by the first bus bar, and the plurality of second interdigital electrodes among the plurality of second electrodes are connected by the second bus bar; the finger pitch P and the thickness dimension H of the multi-layer piezoelectric layer satisfy: P / H ≥ 1; the width dimension of each first interdigital electrode is t1, the distance between every two adjacent first interdigital electrodes and second interdigital electrodes is t2, and the finger pitch P = t1 + t2. The width dimension is the dimension parallel to the surface of the substrate and perpendicular to the extending direction of the first interdigital electrode.

[0024] In order to increase the resonant frequency of the resonator, the finger pitch P can be reduced. However, a smaller finger pitch P will not only pose a challenge to the etching process but also introduce parasitic modes; in the embodiments of this application, due to the use of a multi-layer stacked piezoelectric layer, by defining the ratio of the finger pitch to the piezoelectric layer thickness, it will neither pose a challenge to the etching process nor suppress parasitic modes.

[0025] In one possible implementation, for the thickness dimension S1 of the first piezoelectric layer and the thickness dimension S2 of the second piezoelectric layer, S1 and S2 are equal or approximately equal.

[0026] In one possible implementation, based on applying voltages to a plurality of second electrodes, a resonator is configured to excite a multi-layer piezoelectric layer to generate a first resonance mode, and the vibration direction of the first resonance mode is parallel to the extension direction of the second electrodes.

[0027] In one possible implementation, the electromechanical coupling coefficient Kt of the resonator 2 ≥ 24%.

[0028] In one possible implementation, the piezoelectric materials of the first piezoelectric layer and the second piezoelectric layer include at least one combination of a combination of niobium and lithium and a combination of tantalum and lithium.

[0029] In one possible implementation, a dielectric layer is stacked between the substrate and the first electrode, and the thickness g of the dielectric layer satisfies: g = λ / 4, where λ is the wavelength of the acoustic wave in the material of the dielectric layer of the resonator at the resonance frequency.

[0030] By providing a dielectric layer between the substrate and the first electrode, coupling between the piezoelectric layer and the substrate is prevented, and thus, the electromechanical coupling coefficient of the device can be increased. Moreover, when the thickness g of the dielectric layer satisfies: g = λ / 4, the electromechanical coupling coefficient can be further improved.

[0031] In one possible implementation, the first piezoelectric layer and the second piezoelectric layer are adjacent layers.

[0032] In one possible implementation, the polarities of the first piezoelectric layer and the second piezoelectric layer are opposite.

[0033] In this way, it is more capable of exciting a larger mechanical vibration inside the piezoelectric layer, further improving the electromechanical coupling coefficient.

[0034] In one possible implementation, the piezoelectric tensor components e 31 、e 32 、e 33 、e 14 、e 24 、e 15 、e 25 、e 36 of the piezoelectric material of the first piezoelectric layer are the same as the piezoelectric tensor components e 31 、e 32 、e 33 、e 14 、e 24 、e 15 、e 25 、e 36 of the piezoelectric material corresponding to the second piezoelectric layer; the piezoelectric tensor components e 11 、e 12 、e 13 、e 16 、e21 , e 22 , e 23 , e 26 , e 35 , the piezoelectric tensor components e corresponding to the piezoelectric material of the second piezoelectric layer 11 , e 12 , e 13 , e 16 , e 21 , e 22 , e 23 , e 26 , e 35 are opposite.

[0035] When the first piezoelectric layer is rotated 180° about an axis perpendicular to the plane of the first piezoelectric layer and the two piezoelectric layers satisfy the above requirements for piezoelectric tensor components, the polarities of the two piezoelectric layers can be opposite.

[0036] In an implementable manner, the piezoelectric tensor components e of the piezoelectric material of the first piezoelectric layer 11 , e 12 , e 13 , e 14 , e 25 , e 35 , e 26 , e 36 , are the same as the piezoelectric tensor components e corresponding to the piezoelectric material of the second piezoelectric layer; the piezoelectric tensor components e of the piezoelectric material of the first piezoelectric layer 11 , e 12 , e 13 , e 14 , e 25 , e 35 , e 26 , e 36 are opposite to the piezoelectric tensor components e corresponding to the piezoelectric material of the second piezoelectric layer. 15 , e 16 , e 21 , e 22 , e 23 , e 24 , e 31 , e 32 , e 33 , are opposite to the piezoelectric tensor components e corresponding to the piezoelectric material of the second piezoelectric layer 15 , e 16 , e 21 , e 22 , e 23 , e 24 , e 31 , e 32 , e 33 are opposite.

[0037] When the first piezoelectric layer is rotated 180° about an axis parallel to the plane of the first piezoelectric layer and perpendicular to the extending direction of the second electrode, and when the two piezoelectric layers meet the requirements of the above piezoelectric tensor components, the polarities of the two piezoelectric layers can be opposite.

[0038] In an implementable manner, the Euler angles of the crystal of the piezoelectric material of the first piezoelectric layer are (0°, 90°, 0°), and the Euler angles of the crystal of the piezoelectric material of the second piezoelectric layer are (0°, 90°, 180°), or,

[0039] the Euler angles of the crystal of the piezoelectric material of the first piezoelectric layer are (0°, 270°, 0°), and the Euler angles of the crystal of the piezoelectric material of the second piezoelectric layer are (0°, 270°, 180°), or,

[0040] the Euler angles of the crystal of the piezoelectric material of the first piezoelectric layer are (90°, 90°, 210°), and the Euler angles of the crystal of the piezoelectric material of the second piezoelectric layer are (90°, 90°, 30°).

[0041] On the other hand, the present application also provides a filter, which may include a plurality of electrically connected resonators, and at least one of the plurality of resonators may be the resonator involved above.

[0042] Since the filter provided by the present application includes the resonator in the above implementation structure, and in this resonator, there are at least two piezoelectric layers with opposite polarization directions, the resonator has a large electromechanical coupling coefficient. When such a resonator is applied in a filter, the out-of-band rejection performance of the filter can be improved.

[0043] On yet another aspect, the present application also provides a duplexer, which includes a transmit channel filter and a receive channel filter, and at least one of the transmit channel filter and the receive channel filter may perform filtering using the filter described above.

[0044] On still another aspect, the present application also provides a multiplexer, which includes a plurality of transmit channel filters and a plurality of receive channel filters, wherein at least one of the plurality of transmit channel filters, or at least one of the plurality of receive channel filters may use the filter involved in the embodiments of the present application.

[0045] On still another aspect, the present application also provides an electronic device, which includes an amplifier, and the filter, duplexer or multiplexer in the above implementable manner, and the filter, duplexer or multiplexer may be electrically connected to the amplifier.

[0046] The electronic device provided by the embodiment of the present application includes the above filter, duplexer or multiplexer. Therefore, the electronic device provided by the embodiment of the present application and the filter, duplexer or multiplexer of the above technical solution can solve the same technical problems and achieve the same expected effects.

[0047] In another aspect, the present application also provides a preparation method of a resonator, and the preparation method includes:

[0048] Fabricating a first electrode on a substrate;

[0049] Fabricating a stacked first piezoelectric layer and a second piezoelectric layer on the first electrode, and fabricating a plurality of second electrodes on the second piezoelectric layer, and the plurality of second electrodes are arranged side by side along a first direction;

[0050] Wherein, the piezoelectric material of the first piezoelectric layer has a first piezoelectric tensor component e 34 , and the piezoelectric material of the second piezoelectric layer has a second piezoelectric tensor component e 34 , and the first piezoelectric tensor component e 34 and the second piezoelectric tensor component e 34 are opposite.

[0051] In the resonator fabricated by using the preparation method of the present application, since the first piezoelectric tensor component e 34 of the piezoelectric material of the first piezoelectric layer and the second piezoelectric tensor component e 34 of the piezoelectric material of the second piezoelectric layer are opposite, then, coupled resonance will occur at the position where the first piezoelectric layer and the second piezoelectric layer are bonded, so that mechanical vibration will also be generated inside the entire piezoelectric layer, thereby, the electromechanical coupling coefficient of the entire resonator can be improved.

[0052] In a feasible implementation manner, fabricating a first electrode on a substrate, fabricating a stacked first piezoelectric layer and a second piezoelectric layer on the first electrode, and fabricating a plurality of second electrodes on the second piezoelectric layer includes:

[0053] Fabricating a first electrode on one side of a first piezoelectric wafer, bonding the substrate to the first piezoelectric wafer, thinning the first piezoelectric wafer to fabricate a first piezoelectric layer, and the first electrode is located between the first piezoelectric layer and the substrate;

[0054] Bonding a second piezoelectric wafer to the first piezoelectric wafer, thinning the second piezoelectric wafer to fabricate a stacked first piezoelectric layer and a second piezoelectric layer;

[0055] Fabricating a plurality of second electrodes on the second piezoelectric layer.

[0056] This example can fabricate a resonator with multiple piezoelectric layers by using the method of piezoelectric wafer bonding.

[0057] In one possible implementation, the preparation method further includes: forming a trench on the first piezoelectric layer and the second piezoelectric layer at a position opposite to the interval between two adjacent second electrodes, such that the trench communicates with the interval.

[0058] The trench can be used to further improve the electromechanical coupling coefficient, or can also suppress parasitic modes.

[0059] On the other hand, the present application also provides a preparation method for a filter, which can include the preparation method of the above resonator.

[0060] For the filter prepared by this method, due to the first piezoelectric tensor component e of the piezoelectric material of the first piezoelectric layer 34 and the second piezoelectric tensor component e of the piezoelectric material of the second piezoelectric layer 34 being opposite, then, coupling resonance will occur at the position where the first piezoelectric layer and the second piezoelectric layer are bonded, such that mechanical vibration will also be generated inside the entire piezoelectric layer. Thus, the electromechanical coupling coefficient of the entire resonator can be improved, and the performance of the filter can be optimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is a schematic diagram of a partial structure in an electronic device;

[0062] Figure 2 It is a schematic diagram of a partial structure in an electronic device;

[0063] Figure 3 It is a schematic diagram of a partial structure of a filter in an electronic device;

[0064] Figure 4 It is a schematic diagram of a partial structure of a resonator;

[0065] Figure 5 It shows a schematic diagram of a partial structure of a resonator provided by an embodiment of the present application;

[0066] Figure 6 It shows a schematic diagram of a structure for embodying the vibration of a resonator provided by an embodiment of the present application;

[0067] Figure 7 It shows a schematic diagram of a structure for embodying the vibration of a resonator provided by the related art;

[0068] Figure 8 It shows a schematic diagram of a structure for embodying the vibration of a resonator provided by the related art;

[0069] Figure 9 It shows a schematic diagram of a partial structure of a resonator provided by an embodiment of the present application;

[0070] Figure 10Shown is a partial structural schematic diagram of a resonator provided by an embodiment of the present application;

[0071] Figure 11 Shown is a structural schematic diagram for reflecting the vibration of a resonator provided by the related art;

[0072] Figure 12 Shown is a structural schematic diagram for reflecting the vibration of a resonator provided by an embodiment of the present application;

[0073] Figure 13 Shown is a partial structural schematic diagram of a resonator provided by an embodiment of the present application;

[0074] Figure 14 Shown is a partial structural schematic diagram of a resonator provided by an embodiment of the present application;

[0075] Figure 15A Shown is a structural schematic diagram for reflecting the vibration of a resonator provided by the related art;

[0076] Figure 15B Shown is a structural schematic diagram for reflecting the vibration of a resonator provided by an embodiment of the present application;

[0077] Figure 16A Shown is a structural schematic diagram for reflecting the vibration of a resonator provided by the related art;

[0078] Figure 16B Shown is a structural schematic diagram for reflecting the vibration of a resonator provided by an embodiment of the present application;

[0079] Figure 17A Shown is Figure 15A the admittance curve of the shown structure;

[0080] Figure 17B Shown is Figure 15B the admittance curve of the shown structure;

[0081] Figure 18 Shown is a partial structural schematic diagram of a resonator provided by an embodiment of the present application;

[0082] Figure 19 Shown is a partial structural schematic diagram of a resonator provided by an embodiment of the present application;

[0083] Figure 20 Shown is a partial structural schematic diagram of a resonator provided by an embodiment of the present application;

[0084] Figure 21 Shown is a structural schematic diagram for reflecting the vibration of a resonator provided by the related art;

[0085] Figure 22 Shown is Figure 20 the admittance curve of the structure shown;

[0086] Figure 23 Shown is Figure 21 the admittance curve of the structure shown;

[0087] Figure 24 Shown is Figure 20 the admittance curve of the structure shown;

[0088] Figure 25 Shown is Figure 21 the admittance curve of the structure shown;

[0089] Figure 26 The flowchart of a method for manufacturing a resonator provided by an embodiment of the present application;

[0090] Figures 27A to 27F The process structure diagram after each step in a method for manufacturing a resonator provided by an embodiment of the present application;

[0091] Figure 28 The schematic structural diagram of a filter provided by an embodiment of the present application;

[0092] Figure 29 For Figure 28 the admittance curves of the respective resonators and the filter bandpass diagram in

[0093] Reference numerals:

[0094] 100 - electronic device;

[0095] 200 - filter;

[0096] 300 - resonator;

[0097] 400, 410, 420, 430, 440 - resonators;

[0098] 500 - antenna;

[0099] 600 - receiver;

[0100] 700 - transmitter;

[0101] 800 - baseband chip;

[0102] 900 - switch;

[0103] 60a, 60c, 70a - filters; 60b - low noise amplifier; 60d - mixer; 60e - buffer; 60f, 70d - voltage controlled oscillator; 70b - amplifier; 70c - driver;

[0104] 10 - Substrate; 101 - Cavity;

[0105] 20 - First electrode;

[0106] 30 - Piezoelectric layer; 301 - First piezoelectric layer; 302 - Second piezoelectric layer;

[0107] 40 - Second electrode; 401 - First interdigital electrode; 402 - Second interdigital electrode;

[0108] 50 - Dielectric layer;

[0109] 601 - First bus bar; 602 - Second bus bar;

[0110] 70 - Groove. Detailed implementation manners

[0111] Before introducing the structures that can be realized in the embodiments of the present application, the technical terms involved in the embodiments of the present application are first introduced.

[0112] Piezoelectric effect: including the direct piezoelectric effect and the inverse piezoelectric effect. The direct piezoelectric effect means that when a piezoelectric material is subjected to a mechanical force, its polarization will change; while the inverse piezoelectric effect means that after an external electric field is applied to the piezoelectric material, the material will deform. The main reasons for the piezoelectric effect are mainly the anisotropy of the crystal structure of the piezoelectric material itself and the polarization effect.

[0113] Main resonance mode, parasitic hybrid mode: The position of the parasitic resonance frequency generated by the resonator may be close to the main resonance frequency position. The parasitic resonance may affect the main resonance mode, and thus affect the in-band insertion loss performance and out-of-band rejection performance of the filter. The parasitic resonance of the resonator is usually called a hybrid mode, or a parasitic hybrid mode. When the hybrid mode falls near the main resonance mode, for example, near the resonance point and anti-resonance point of the main resonance mode, it will affect the in-band insertion loss performance and out-of-band rejection performance of the filter.

[0114] Piezoelectric coupling factor Kt 2 : is a key parameter of the resonator. The piezoelectric coupling factor Kt 2 can reflect the conversion efficiency between mechanical energy and electrical energy. The piezoelectric coupling factor Kt of the resonator 2 determines the relative frequency width between the anti-resonance frequency and the resonance frequency of the resonator. For example, when the resonator is applied to filter design, this relative frequency width directly determines the bandwidth of the filter. It can be considered that the piezoelectric coupling factor Kt 2 is larger, the bandwidth of the filter built by the ladder structure can be larger, and the performance is better.

[0115] For single-crystal piezoelectric materials, it has a fourth-order elastic tensor c, a third-order piezoelectric tensor e, and a second-order dielectric tensor ε. According to the right-handed rectangular coordinate system, it has elastic tensor components c ijkl , piezoelectric tensor components e ijk , and dielectric tensor components ε ij , where i, j, k, l = {1, 2, 3}. Due to the symmetry of the single-crystal structure, for example, c 1323 = c 3132 , the order of the components can be simplified. Define {23, 32} → 4, {13, 31} → 5, {12, 21} → 6. For example, c 1323 = c 3132 → c 54 . Then there are elastic tensor components c xy (6*6), piezoelectric tensor components e ix (3*6), and dielectric tensor components ε ij (3*3), where i, j = {1, 2, 3}, x, y = {1, 2, 3, 4, 5, 6}. The electromechanical coupling coefficient component kxy 2 is calculated from the elastic tensor components, piezoelectric tensor components, and dielectric tensor components of the material. The formula is:

[0116]

[0117] where x = {1, 2, 3}, y = {1, 2, 3, 4, 5, 6}, ε xx S is the dielectric tensor component under fixed strain, and c yy E is the elastic tensor component under fixed electric field strength.

[0118] The following explains the calculation methods and formulas of each elastic tensor component, piezoelectric tensor component, and dielectric tensor component at different crystal Euler angles.

[0119] For the crystal orientation of the piezoelectric material with Euler angles (0, 0, 0), taking LN as an example,

[0120] c E 11 = 2.03, c E 12 = 0.53, c E 13 = 0.75, c E 14 = 0.09, c E 44 = 0.60, c E 33 = 2.43, c E 22 = c E11 , c E 23 = c E 13 , c E 24 = -c E 14 , c E 55 = c E 44 , c E 56 = c E 14 , c E 66 = (c E 11 - c E 12 ) / 2, unit: *10 11 N / m 2 ;

[0121] e 15 = 3.70, e 16 = -2.53, e 31 = 0.19, e 33 = 1.31, e 21 = e 16 , e 22 = -e 16 , e 24 = e 15 , e 32 = e 31 , unit: C / m 2 ; ε S 11 = 43.6 * ε 0 , ε S 33 = 29.2 * ε 0 , ε S 22 = ε S 11 , where ε0 is the vacuum permittivity, 8.85 * 10 -12 F / m. The remaining components can be obtained through tensor symmetry, and the components without numerical values are zero. Among them, the expression method of the components in simplified form, for the fourth-order elastic tensor component c E ijkl and the third-order piezoelectric tensor component e ijk , can be expanded accordingly.

[0122] Now, for the crystal orientation of the piezoelectric material with Euler angles (α, β, γ), its corresponding elastic tensor component c E pqrs’, the piezoelectric tensor component e pqr ’, the dielectric tensor component ε S pq ’ can be calculated by the following formula:

[0123] c E pqrs ’ = c E ijkl A ip A jq A kr A ls ;

[0124] e pqr ’ = e ijk A ip A jq A kr ;

[0125] ε S pq ’ = ε S ij A ip A jq ;

[0126] The formula adopts the Einstein summation convention, where the 3*3 matrix A = (cosαcosγ - sinαcosβsinγ, -cosαsinγ - sinαcosβcosγ, sinαsinβ; sinαcosγ + cosαcosβsinγ, -sinαsinγ + cosαcosβcosγ, -cosαsinβ; sinβsinγ, sinβcosγ, cosβ).

[0127] The Euler angle of the piezoelectric material: The Euler angle characterizes the relative rotation angle relationship between the direction perpendicular to or parallel to the resonator finger extension direction in the wafer plane and the X direction or Y direction of the original piezoelectric crystal structure respectively.

[0128] Admittance: In power electronics, admittance is defined as the reciprocal of impedance, symbol Y, unit Siemens, abbreviated as S. Like impedance, admittance is also a complex number, consisting of a real part (conductance G) and an imaginary part (susceptance B): Y = G + jB.

[0129] Admittance curve abs and admittance curve Re: The admittance curve abs(Y) = |Y|, which is the modulus of Y (also called amplitude), representing the overall response of the resonator. Re(Y) is the real part of Y, that is, the conductance G, representing the loss of the resonator.

[0130] Embodiments of the present application provide an electronic device, which includes, but is not limited to, products such as a radio frequency front end and a filter amplification module, and may also include terminal devices such as a mobile phone, a pad, intelligent wearable products (e.g., smart watches, smart bracelets), virtual reality (VR) devices, augmented reality (AR), drones, or may also be devices such as a base station, a television, a router, a car, etc. Embodiments of the present application do not impose special restrictions on the specific form of the above-mentioned electronic device.

[0131] In an electronic device such as the above, as Figure 1 shown, the electronic device 100 may include a filter 200, and the filter 200 may effectively filter out frequency points of a specific frequency or frequencies other than that frequency point in a signal, to obtain a signal of a specific frequency, or a signal after eliminating a specific frequency, so as to improve the working performance of the electronic device 100.

[0132] Figure 2 Some circuit diagrams in some electronic devices 100 are given. Among them, see Figure 2 , the electronic device 100 includes a Receiver 600, a Transmitter 700, an Antenna 500, and a baseband chip 800. The Antenna 500 is electrically connected to the Receiver 600 and the Transmitter 700 respectively through a switch 900, and the Receiver 600 and the Transmitter 700 are electrically connected to the baseband chip 800 respectively.

[0133] In Figure 2 the shown Receiver 600, it includes a Filter 60a and a Filter 60c. A low-noise amplifier 60b is electrically connected between the Filter 60a and the Filter 60c. The Filter 60c is electrically connected to a Buffer 60e through a Mixer 60d, and the Buffer 60e is electrically connected to a voltage-controlled oscillator 60f. Figure 2 This is only an exemplary receiver, and electronic devices can be added or reduced based on this circuit structure.

[0134] In Figure 2 the shown Transmitter 700, it includes a power amplifier (PA) 70b. The power amplifier 70b is electrically connected to a Filter 70a and a Driver 70c respectively, and the Driver 70c is electrically connected to a voltage-controlled oscillator 70d. Similarly, Figure 2It is only an exemplary transmitter, and electronic devices can be added or reduced based on this circuit structure.

[0135] For example, in Figure 2 the transmitter 700 shown, the filter can effectively filter out specific frequency points amplified by the power amplifier or frequencies other than that frequency point, or the filter can filter out the noise of the low-noise amplifier.

[0136] Again, for example Figure 3 as shown, the filter 200 can include a plurality of resonators 300 connected in series, or include a plurality of resonators 300 connected in parallel, or include resonators 300 combined in series and parallel.

[0137] At least one of the plurality of resonators included in the filter 200 can be Figure 4 the resonator shown.

[0138] Such as Figure 4 , Figure 4 shows a part of the process structure diagram of a resonator. Among them, the resonator includes a substrate 10, a first electrode 20, a piezoelectric layer 30, and a plurality of second electrodes 40. The first electrode 20, the piezoelectric layer 30, and the plurality of second electrodes 40 are disposed on the substrate 10. The plurality of second electrodes 40 are arranged side by side in the first direction. The piezoelectric layer 30 has a first side and a second side. The plurality of second electrodes 40 are located on the first side, and the first electrode 20 is located on the second side. The first side faces away from the substrate 10, and the second side faces the substrate 10. Exemplarily, as Figure 4 shown, the piezoelectric layer 30 is stacked between the first electrode 20 and the plurality of second electrodes 40.

[0139] In the above Figure 4 exemplary resonator, the plurality of second electrodes 40 arranged in the first direction, and the first direction can be understood as a direction perpendicular to or nearly perpendicular to the extending direction of the second electrode 40. In one embodiment, the first direction is perpendicular to the stacking direction of the piezoelectric layer 30 with the first electrode 20 and the second electrode 40.

[0140] Figure 4 The exemplary structure can be used for a bulk acoustic wave resonator. The main principle of the bulk acoustic wave resonator is to utilize the piezoelectric effect characteristics of piezoelectric materials, and use input and output transducers to convert the input signal of the electric wave into mechanical energy. After processing, the mechanical energy is then converted into an electric signal to achieve the goal of filtering out unnecessary signals and noise and improving the receiving quality.

[0141] Figure 4When the shown resonator is operating, the first electrode 20 may not be electrically connected, and an alternating voltage of a certain frequency is applied to the second electrode 40, so that an electric field E is generated between the first electrode 20 and the second electrode 40 along the thickness direction of the piezoelectric layer 30, and the piezoelectric layer 30 utilizes this electric field to form a piezoelectric effect. Figure 4 The example is to utilize the vertical electric field E to excite the piezoelectric layer 30 to generate resonance, and then generate the conversion between electrical energy and mechanical energy.

[0142] Figure 4 The shown resonator excites resonance in the thickness direction of the piezoelectric layer 30. In one embodiment, it can be called a vertically-excited bulk acoustic resonator (YBAR). Here, the thickness direction of the piezoelectric layer 30 can be understood as the direction parallel to the stacking direction of multiple film layers (substrate, first electrode, piezoelectric layer) on the piezoelectric layer 30.

[0143] See Figure 4 , since the part of the piezoelectric layer 30 close to the first electrode 20 (such as the Q region outlined by the dotted line as shown) adheres to the first electrode 20, this will limit the acoustic resonance vibration of this region (such as the Q region outlined by the dotted line as shown), limit the vibration amount of the piezoelectric layer 30, and result in a relatively small electromechanical coupling coefficient Kt of this resonator. Figure 4 As shown, the Q region outlined by the dotted line) adheres to the first electrode 20, thus restricting the acoustic resonance vibration of this region (such as the Q region outlined by the dotted line as shown), defining the vibration amount of the piezoelectric layer 30, and leading to a relatively small electromechanical coupling coefficient Kt of this resonator. Figure 4 As shown, the Q region outlined by the dotted line), resulting in a relatively small electromechanical coupling coefficient Kt of this resonator and making it unable to be applied in a larger passband bandwidth. For example, it cannot meet the passband bandwidth requirements of the frequency band from Sub-6GHz to Sub-15GHz. 2 For example, it cannot meet the passband bandwidth requirements of the frequency band from Sub-6GHz to Sub-15GHz.

[0144] To improve the electromechanical coupling coefficient Kt of the resonator 2 , some novel resonator process structures are exemplarily given in this application, as described below.

[0145] Such as Figure 5 , Figure 5 is a process structure diagram of a resonator given in an embodiment of this application. The same as the above Figure 4 : The resonator includes a substrate 10, a first electrode 20 stacked on the substrate 10, a piezoelectric layer 30, and multiple second electrodes 40; and the similarities also include: the second electrode 20 has a first surface and a second surface facing each other, the first surface is closer to the piezoelectric layer 30 than the second surface, and the second surface of the first electrode 20 is completely disposed on the substrate 10. Such a resonator can be called a solid-state substrate resonator.

[0146] Figure 5 The differences between the shown example and Figure 4 include: in Figure 5 , the piezoelectric layer 30 includes multiple layers stacked, for example, Figure 5Exemplarily, a first piezoelectric layer 301 and a second piezoelectric layer 302 arranged in a stacked manner are shown. In some other examples, more piezoelectric layers may be included, for example, three layers, four layers or more layers.

[0147] Among the multiple piezoelectric layers, some piezoelectric tensor components of the piezoelectric materials of two adjacent piezoelectric layers are opposite. For example, as Figure 5 , the piezoelectric material of the first piezoelectric layer 301 has a first piezoelectric tensor component, and the piezoelectric material of the second piezoelectric layer 302 has a second piezoelectric tensor component, and the first piezoelectric tensor component and the second piezoelectric tensor component are opposite.

[0148] In some examples, the substrate 10 can be a high sound velocity substrate. For example, any one of silicon carbide (SiC), diamond, boron nitride (BN), or a combination of multiple ones can be used.

[0149] The first electrode 20 can be any possible conductive metal, including but not limited to Al, Cu, W, Mo, Ru, Pt, etc. Also, a conductive metal with a high acoustic impedance can be selected, including but not limited to W, Ru, Mo, Pt, etc. These metals with high acoustic impedance help increase the electromechanical coupling coefficient and improve the quality factor Q, further enhancing the performance of the resonator.

[0150] The second electrode 40 can be any possible conductive metal, including but not limited to Al, Cu, W, Mo, Ru, Pt, etc.

[0151] The first electrode 20 and the second electrode 40 can be the same conductive metal or different conductive metals.

[0152] In the examples of this application, the piezoelectric material of the first piezoelectric layer 301 has a first piezoelectric tensor component e 34 , and the piezoelectric material of the second piezoelectric layer 302 has a second piezoelectric tensor component e 34 , where the first piezoelectric tensor component e 34 and the second piezoelectric tensor component e 34 are opposite.

[0153] The first piezoelectric tensor component e 34 and the second piezoelectric tensor component e 34 in the examples of this application are opposite, which can be understood as: the first piezoelectric tensor component e 34 and the second piezoelectric tensor component e 34 are opposite numbers to each other.

[0154] The first piezoelectric tensor component e 34 and the second piezoelectric tensor component e 34 are opposite numbers to each other. In some examples, the first piezoelectric tensor component e 34The absolute value and the second piezoelectric tensor component e 34 have exactly the same absolute value, or, the absolute value of the first piezoelectric tensor component e 34 can be set as X1, and the absolute value of the second piezoelectric tensor component e 34 can be set as X2.

[0155] In the bulk acoustic wave resonator YBAR provided by the present application, the main resonance mode of the bulk acoustic wave resonator YBAR can be determined by the piezoelectric tensor component e 34 ; the absolute value of the piezoelectric tensor component e 34 can be the maximum value among the absolute values of all piezoelectric tensor components, or, it can also be less than the maximum value among the absolute values of piezoelectric tensor components. For example, it can be greater than or equal to 70% of the maximum value among the absolute values of piezoelectric tensor components.

[0156] In some realizable structures, the first piezoelectric layer 301 and the second piezoelectric layer 302 can be two adjacent layers. In some other examples, other piezoelectric layers can also be stacked between the first piezoelectric layer 301 and the second piezoelectric layer 302.

[0157] In some examples, the piezoelectric materials of the first piezoelectric layer 301 and the second piezoelectric layer 302 can include at least one combination of a combination of niobium and lithium, and a combination of tantalum and lithium. For example, the materials of the first piezoelectric layer 301 and the second piezoelectric layer 302 include any one of lithium tantalate (LiTaO3), lithium niobate (LiNbO3), aluminum nitride (AlN), zinc oxide (ZnO), or a combination of multiple ones.

[0158] In the examples of the present application, under the action of the piezoelectric tensor component e 34 , the first piezoelectric layer 301 and the second piezoelectric layer 302 vibrate along the extending direction of the second electrode 40.

[0159] In some examples, both the first piezoelectric layer 301 and the second piezoelectric layer 302 contain lithium niobate (LiNbO3). When the Euler angles of the crystal of the piezoelectric material of the first piezoelectric layer 301 are (0°, 90°, 0°), the piezoelectric tensor component e 34 of the piezoelectric material of the first piezoelectric layer 301 is +3.696. When the Euler angles of the crystal of the piezoelectric material of the second piezoelectric layer 302 are (0°, 90°, 180°), the piezoelectric tensor component e 34 of the piezoelectric material of the second piezoelectric layer 302 is -3.696.

[0160] In some other examples, both the first piezoelectric layer 301 and the second piezoelectric layer 302 include lithium niobate (LiNbO3). When the Euler angles of the crystal of the piezoelectric material of the first piezoelectric layer 301 are (0°, 270°, 0°), the piezoelectric tensor component e of the piezoelectric material of the first piezoelectric layer 301 34 = -3.696. When the Euler angles of the crystal of the piezoelectric material of the second piezoelectric layer 302 are (0°, 270°, 180°), the piezoelectric tensor component e of the piezoelectric material of the second piezoelectric layer 302 34 = +3.696.

[0161] In the examples of this application, the Euler angles (0°, 90°, 0°), the Euler angles (0°, 90°, 180°), the Euler angles (0°, 270°, 0°), and the Euler angles (0°, 270°, 180°) can allow for a certain error range.

[0162] For example, they can be the Euler angles (0°±5°, 90°±5°, 0°±5°), the Euler angles (0°±5°, 90°±5°, 180°±5°), the Euler angles (0°±5°, 270°±5°, 0°±5°), and the Euler angles (0°±5°, 270°±5°, 180°±5°).

[0163] Figure 6 Exemplarily shows the structure of this application Figure 5 and how to improve the electromechanical coupling coefficient Kt 2 principle.

[0164] In Figure 6 , both the first piezoelectric layer 301 and the second piezoelectric layer 302 can adopt lithium niobate (LiNbO3), and the vibration directions of the first piezoelectric layer 301 and the second piezoelectric layer 302 are along direction 2. The first piezoelectric layer 301 is closer to the first electrode 20 than the second piezoelectric layer 302, Figure 6 Exemplarily shows the second electrode 401 and the second electrode 402 in the second electrode. Figure 6 The filling pattern in

[0165] schematically indicates the approximate area where the resonator vibrates. 34 . For example, when a positive voltage is applied to the second electrode 401, since the first piezoelectric layer 301 and the second piezoelectric layer 302 have opposite piezoelectric tensor components e Figure 6 . The part of the second piezoelectric layer 302 close to the second electrode 401 (such as Figure 6 the A1 part) vibrates in the negative direction of direction 2, and the part of the second piezoelectric layer 302 close to the first piezoelectric layer 301 (such as Figure 6The C1 part of ) vibrates in the positive direction of direction 2, and the part of the first piezoelectric layer 301 close to the first electrode 20 (such as Figure 6 The D1 part of ) vibrates in the negative direction of direction 2.

[0166] Such as Figure 6 , located between the second electrode 401 and the first electrode 20, at the bonding position of the first piezoelectric layer 301 and the second piezoelectric layer 302, the two positive vibrations along direction 2 are coupled, so that mechanical vibration is generated inside the entire piezoelectric layer.

[0167] For another example, when a negative voltage is applied to the second electrode 401, the part of the second piezoelectric layer 302 close to the second electrode 401 (such as Figure 6 The A2 part of ) vibrates in the positive direction of direction 2, and the part of the second piezoelectric layer 302 close to the first piezoelectric layer 301 (such as Figure 6 The B2 part of ) vibrates in the negative direction of direction 2; the part of the first piezoelectric layer 301 close to the second piezoelectric layer 302 (such as Figure 6 The C2 part of ) vibrates in the negative direction of direction 2, and the part of the first piezoelectric layer 301 close to the first electrode 20 (such as Figure 6 The D2 part of ) vibrates in the positive direction of direction 2.

[0168] Such as Figure 6 , located between the second electrode 402 and the first electrode 20, at the bonding position of the first piezoelectric layer 301 and the second piezoelectric layer 302, the two negative vibrations along direction 2 are coupled, so that mechanical vibration is generated inside the entire piezoelectric layer.

[0169] Therefore, in the resonator structure exemplified in the present application Figure 6 In the case where the piezoelectric tensor components e of adjacent piezoelectric layers 34 Are opposite to each other, coupled resonance will occur at the interface of the multi-layer piezoelectric layer, so that mechanical vibration is generated inside the entire piezoelectric layer, thereby, the electromechanical coupling coefficient Kt can be improved 2 .

[0170] In the example of the present application, since there is a gap between the second electrode 401 and the second electrode 402, compared with a resonator in which the second electrode 401 and the second electrode 402 are connected as a whole (such as a thin film cavity acoustic resonator FBAR), the present application Figure 6 The second electrode 401 in is not restricted by the second electrode 402 and has greater freedom. Furthermore, such as Figure 6 , the second electrode 402 can also vibrate along direction 2 to increase the vibration amount of the entire resonator.

[0171] Similarly, since there is a gap between the second electrode 401 and the second electrode 402, compared with a resonator in which the second electrode 401 and the second electrode 402 are connected as a whole (such as a thin film bulk acoustic resonator FBAR), in the present application Figure 6 the second electrode 402 will not be restricted by the second electrode 401 or other second electrodes, enabling the second electrode 402 to have greater freedom. Furthermore, as Figure 6 , the second electrode 402 can also vibrate along direction 2 to increase the vibration amount of the entire resonator.

[0172] In this way, the electromechanical coupling coefficient Kt of the resonator can be further increased 2 .

[0173] The polarities of the first piezoelectric layer 301 and the second piezoelectric layer 302 can be opposite, which can make the vibration amplitude in the piezoelectric layer larger and further increase the electromechanical coupling coefficient.

[0174] In some implementable ways, such as Figure 6 , the first piezoelectric layer 301 can be rotated 180° around an axis perpendicular to the plane of the first piezoelectric layer 301 (such as Figure 7 direction 3) to obtain the second piezoelectric layer 302 with the opposite polarity to the first piezoelectric layer 301. Then, the piezoelectric tensor components e 31 、e 32 、e 33 、e 14 、e 24 、e 15 、e 25 、e 36 of the first piezoelectric layer 301 and the second piezoelectric layer 302 are the same, and the remaining piezoelectric tensor components are opposite to each other. For example, e 11 、e 12 、e 13 、e 16 、e 21 、e 22 、e 23 、e 26 、e 34 、e 35 are opposite to each other.

[0175] In some other implementable ways, such as Figure 6 , the first piezoelectric layer 301 can be rotated 180° around an axis parallel to the plane of the first piezoelectric layer 301 and perpendicular to the extending direction of the second electrode (such as Figure 7 direction 1) to obtain the second piezoelectric layer 302 with the opposite polarity to the first piezoelectric layer 301. Then, the piezoelectric tensor components e 11 、e 12 、e 13 、e14 and e 25 and e 35 and e 26 and e 36 are the same, and the remaining piezoelectric tensor components are opposite to each other. For example, e 15 and e 16 and e 21 and e 22 and e 23 and e 24 and e 31 and e 32 and e 33 and e 34 are opposite to each other.

[0176] Figure 7 The vibration diagram when adopting a single piezoelectric layer is exemplified. The part of the piezoelectric layer 30 in contact with the second electrode 401 (such as Figure 7 part A1) vibrates in the negative direction of direction 2, and the part of the piezoelectric layer 30 in contact with the first electrode 20 (such as Figure 7 part B1) vibrates in the positive direction of direction 2. Compared with the above Figure 6 , in Figure 7 , basically no vibration occurs inside the entire piezoelectric layer 30, while in the example of the present application Figure 6 , not only the upper and lower surface parts of the piezoelectric layer will vibrate, but also the interface between adjacent piezoelectric layers will vibrate. In some scenarios, even if the vibration of the part of the piezoelectric layer in contact with the first electrode 20 is limited, the resonator of the example of the present application can still improve the electromechanical coupling coefficient Kt 2 .

[0177] Figure 6 and Figure 7 Compared with Figure 6 , the sum of the thickness dimensions 2h of the first piezoelectric layer 301 and the second piezoelectric layer 302 in Figure 7 is basically equal to or approximately equal to the thickness dimension of the piezoelectric layer 30 in Figure 6 . The resonance frequency of Figure 7 is basically the same as or approximately the same as that of

[0178] The resonator of the example of the present application Figure 6 can, on the basis of ensuring that the resonance frequency meets the requirements, also improve the electromechanical coupling coefficient Kt 2 .

[0179] The direction 2 involved in the embodiment of the present application can be understood as: parallel to the extension direction of the second electrode 40. The direction 3 can be understood as: perpendicular to the surface of the substrate 10, or parallel to the stacking direction of the first piezoelectric layer 301 and the second piezoelectric layer 302. The direction 1 can be understood as: parallel to the surface of the substrate 10 and perpendicular to the extension direction of the second electrode 40.

[0180] In some examples, in order to increase the resonance frequency, the resonator shown below can also be adopted Figure 8 compared with Figure 8 and Figure 7 in Figure 8 the thickness dimension of the piezoelectric layer 30 of the single-layer structure is h Figure 7 in Figure 7 the thickness dimension of the piezoelectric layer 30 of the single-layer structure is 2h. For example, in Figure 8 the resonance frequency can be f, and in Figure 7 and Figure 8 the resonance frequency can be 2f, that is, the resonance frequency of the resonator can be increased by reducing the thickness dimension of the piezoelectric layer 30. However, in the process manufacturing, when the resonance frequency is increased by thinning the thickness dimension of the piezoelectric layer 30, it may pose a great challenge to the lithography technology. Therefore, the increase of the resonance frequency is limited

[0181] However, when the resonator shown below is adopted Figure 6 the limitation imposed by the lithography technology can be alleviated by stacking multiple piezoelectric layers. Thus, on the basis of improving the stability and firmness of the resonator, this resonator can be applied in the high-frequency range

[0182] Figure 9 is the process structure diagram of another resonator according to the example of the present application. In this resonator, a cavity 101 is formed in the substrate 10, and such a resonator can be called a cavity-type suspended piezoelectric thin-film resonator

[0183] In Figure 9 the second electrode 20 has a first surface and a second surface facing each other, the first surface is closer to the piezoelectric layer 30 than the second surface, the substrate 10 is provided with a cavity 101, at least part of the second surface of the first electrode 20 is used to enclose the cavity 101, and at least part of the first electrode 20 is disposed between the cavity 101 and the piezoelectric layer 30

[0184] In this example, the piezoelectric layer 30 can also include multiple stacked layers. For example, it includes a first piezoelectric layer 301 and a second piezoelectric layer 302 arranged in a stacked manner. Among the multiple piezoelectric layers, adjacent piezoelectric layers have opposite piezoelectric tensor components. For example, the piezoelectric tensor component e of the first piezoelectric layer 301 34 and the piezoelectric tensor component e of the second piezoelectric layer 302 34 are opposite

[0185] Figure 10 is the process structure diagram of another resonator according to the embodiment of the present application. In this example, a dielectric layer 50 is further included, and the dielectric layer 50 is stacked between the substrate 10 and the first electrode 20. For example, the dielectric layer 50 can be silicon oxide (SiO2 )。

[0186] In some examples, the thickness g of the dielectric layer 50 satisfies: g = λ / 4, where λ is the wavelength of the acoustic wave of the resonator at the resonant frequency in the material of the dielectric layer 50.

[0187] Such as Figure 11 and Figure 12 , in Figure 11 , the piezoelectric layer 30 includes a single layer of piezoelectric layer. In Figure 12 , the piezoelectric layer 30 includes a stacked first piezoelectric layer 301 and a second piezoelectric layer 302, and further includes a dielectric layer 50 stacked between the substrate 10 and the first electrode 20.

[0188] In Figure 11 , since the first electrode 20 of the metal layer is directly stacked on the substrate 10, in this way, the vibration amplitudes of the piezoelectric layer 30 and the first electrode 20 will be limited. As shown in Figure 11 , the vibration area and vibration amplitude are very small. However, as shown in Figure 12 , because a dielectric layer with a lower hardness is stacked between the substrate 10 and the first electrode 20, compared with Figure 11 , mechanical vibrations will also be generated in the first electrode 20 and the dielectric layer 50, thereby increasing the vibration amount of the entire resonator and increasing the electromechanical coupling coefficient Kt. 2 。

[0189] Figure 13 is a process structure diagram of a resonator given in an embodiment of the present application. Figure 14 shows Figure 13 the distribution diagram of the second electrode in

[0190] In Figure 13 and Figure 14 the resonators of the examples, the multiple second electrodes include multiple first interdigital electrodes 401 and multiple second interdigital electrodes 402. For example, along a direction perpendicular to the extending direction of the first interdigital electrodes 401, the multiple first interdigital electrodes 401 and the multiple second interdigital electrodes 402 can be arranged side by side, and the multiple first interdigital electrodes 401 and the multiple second interdigital electrodes 402 are arranged at intervals, that is, a second interdigital electrode 402 can be arranged between two adjacent first interdigital electrodes 401. Alternatively, the first interdigital electrodes 401 and the second interdigital electrodes 402 are spaced in a first direction, and the extending direction of the first interdigital electrodes 401 and / or the second interdigital electrodes 402 is perpendicular to the first direction.

[0191] A plurality of first interdigital electrodes 401 are connected through a first bus bar 601, and a plurality of second interdigital electrodes 402 are connected through a second bus bar 602. For example, the first bus bar 601 and the second bus bar 602 are arranged in parallel, and both the first bus bar 601 and the second bus bar 602 extend along a direction perpendicular to the extending direction of the first interdigital electrodes 401 or the second interdigital electrodes 402, as Figure 14 shown, the first bus bar 601 and the second bus bar 602 extend along the first direction.

[0192] The finger pitch (Pitch) P can be understood as Figure 12 shown, the width of each first interdigital electrode 401 is t1, the distance between every two adjacent first interdigital electrodes 401 and second interdigital electrodes 402 is t2, and the finger pitch (Pitch) P is the sum of the width t1 and the distance t2.

[0193] In some examples, the width dimension t1 of the plurality of first interdigital electrodes 401 has a process tolerance, and the distance t2 between two adjacent first interdigital electrodes 401 and second interdigital electrodes 402 also has a process tolerance.

[0194] The piezoelectric layer thickness, the first electrode thickness, and the second electrode thickness are the height dimensions of the piezoelectric layer, the height dimension of the first electrode, and the height dimension of the second electrode along the stacking direction of the plurality of film layer structures (such as Figure 13 the L direction shown).

[0195] The duty ratio is the ratio of the width s1 of the first interdigital electrode 401 to the finger pitch P, or the ratio of the width of the second interdigital electrode 402 to the finger pitch. In some examples, the widths of the first interdigital electrode 401 and the second interdigital electrode 402 are equal.

[0196] When the resonator operates, acoustic loss will occur at the electrodes, reducing the device operating performance. For example, acoustic loss may occur at the first electrode 20 or at the second electrode 40. To weaken the electrode acoustic loss, in some examples, the thickness dimension of the electrode can be thinned. However, when the thickness dimension of the electrode is reduced, the power tolerance of the electrode will be weakened, shortening the service life of the device.

[0197] In the resonator of the examples of the present application, by adopting a multi-layer stacked piezoelectric layer to increase the thickness dimension of the entire piezoelectric layer, thus, the ratio of the electrode layer thickness dimension to the entire piezoelectric layer thickness dimension can be reduced, and the thicker piezoelectric layer is used to reduce the acoustic loss in the electrodes. In this way, the power tolerance of the electrodes can also be ensured.

[0198] In some examples, such as Figure 13, the thickness dimension of the second electrode layer 40 is S1, and the sum of the thickness dimensions of the first piezoelectric layer and the second piezoelectric layer is S2, where S1 / S2 ≤ 0.35. For example, S1 / S2 ≤ 0.3, or S1 / S2 ≤ 0.2, or S1 / S2 ≤ 0.1.

[0199] In some examples, the thickness dimension of the first electrode is S3, and the sum of the thickness dimensions of the first piezoelectric layer and the second piezoelectric layer is S2, where S3 / S2 ≤ 0.35. For example, S3 / S2 ≤ 0.3, or S3 / S2 ≤ 0.2, or S3 / S2 ≤ 0.1.

[0200] To increase the resonant frequency of the resonator, in some examples, the Figure 14 shown finger pitch can be reduced. However, when the finger pitch is reduced, it poses a challenge to lithography technology. In the examples of this application, the finger pitch P can satisfy the following relationship with the thickness dimension d of the piezoelectric layer 30: P / d ≥ 1;

[0201] In some examples, the resonant frequency of this resonator can be greater than or equal to 3.64 GHz. For example, it can reach 4.34 GHz.

[0202] Next, in combination with the accompanying drawings and tabular data, the electromechanical coupling coefficient of the resonator given in the embodiments of this application and the resonators in the related art will be compared, as well as how to suppress parasitic modes.

[0203] Figure 15A is a process structure diagram of a resonator given in the embodiments of this application, Figure 15A used to show the vibration schematic along direction 2.

[0204] Figure 15B is a process structure diagram of a resonator with one piezoelectric layer, Figure 15B used to show the vibration schematic along direction 2.

[0205] As Figure 15A , there is vibration along direction 2 at the positions where the second piezoelectric layer 302 is in contact with the second electrode 401 and the second electrode 402, there is vibration along direction 2 at the interface between the second piezoelectric layer 302 and the first piezoelectric layer 301, and there is slight vibration along direction 2 at the interface between the dielectric layer 50 and the first electrode 20. The main resonance mode SH1 of this resonator is generated in direction 2, that is, the vibration direction of the main resonance mode SH1 of this resonator is direction 2 parallel to the extension direction of the second electrode 40.

[0206] As Figure 15B, at the positions where the piezoelectric layer 30 is in contact with the second electrode 401 and the second electrode 402, there is vibration in the direction 2, and there is slight vibration in the direction 2 at the interface between the dielectric layer 50 and the first electrode 20. In this resonator, the main resonance mode SH1 of the resonator is generated in the direction 2, that is, the vibration direction of the main resonance mode SH1 of the resonator is the direction 2 parallel to the extension direction of the second electrode 40.

[0207] Compared with Figure 15A and Figure 15B , in the example of the present application Figure 15A , coupled resonance is generated inside the entire piezoelectric layer.

[0208] Figure 16A is Figure 15A The vibration schematic diagram of the resonator shown along the direction 1. Figure 16B is Figure 15B The vibration schematic diagram of the resonator shown along the direction 1.

[0209] In Figure 16A In the example of the figure vibrating along the direction 1, at the positions where the second piezoelectric layer 302 is in contact with the second electrode 401 and the second electrode 402, there is vibration in the direction 1, and there is slight vibration in the direction 1 at the interface between the dielectric layer 50 and the first electrode 20. The parasitic mode S0 of the resonator is generated in the direction 1.

[0210] In Figure 16B In the example of the figure vibrating along the direction 1, the entire piezoelectric layer 30 has vibration in the direction 1, and at the interface between the piezoelectric layer 30 and the first electrode 20, the first electrode 20 also has vibration in the direction 1. The parasitic mode S0 of the resonator is generated in the direction 1.

[0211] Compared with Figure 16A and Figure 16B , in Figure 16B , the vibration area generating the parasitic hybrid mode S0 is larger, while in Figure 16A , the vibration area generating the parasitic hybrid mode S0 is smaller.

[0212] Figure 17A is obtained by using Figure 15A structure and the physical parameter limitations shown in Table 1 to obtain the admittance simulation curve. Figure 17B is obtained by using Figure 15B structure and the physical parameter limitations shown in Table 2 to obtain the admittance simulation curve.

[0213]

[0214] Table 1

[0215]

[0216]

[0217] Table 2

[0218] Comparing Table 1 and Table 2, the physical parameters of the resonators with two different structures are that the finger pitch P is equal, the duty cycle is equal, the thickness of the second electrode is equal, the thickness of the first electrode is equal, and the thickness of the dielectric layer is equal. Since the Euler angles of the two piezoelectric layer materials in Table 1 are rotated by 180°, the piezoelectric polarization directions of the first piezoelectric layer and the second piezoelectric layer are opposite.

[0219] See Figure 17A In the resonator given in the present application as shown, near the resonance point of the SH1 main resonance mode, the excited S0 longitudinal wave hybrid mode is small. While in Figure 17B the admittance curve shown, near the resonance point of the SH1 main resonance mode, a relatively large S0 longitudinal wave hybrid mode is excited.

[0220] In addition, see Figure 17A , in the resonator exemplified in the present application, the electromechanical coupling coefficient Kt 2 reaches 24.2%. While in the resonator with one piezoelectric layer, such as Figure 17B , the electromechanical coupling coefficient Kt 2 is 11.8%. Obviously, the resonator with multiple piezoelectric layers given in the embodiments of the present application can increase the electromechanical coupling coefficient Kt 2 . For example, the electromechanical coupling coefficient Kt 2 can be made greater than or equal to 20%.

[0221] In the resonator exemplified in the present application Figure 15A , the resonance frequency, compared with Figure 15B the resonance frequency of the resonator, is increased from 4.7 GHz to 5.1 GHz.

[0222] Therefore, the resonator including at least two piezoelectric layers exemplified in the present application can not only increase the electromechanical coupling coefficient, improve the resonance frequency, but also suppress parasitic hybrid modes, further optimizing the performance of the resonator.

[0223] Figure 18 , Figure 19 and Figure 20 are the process structure diagrams of three other resonators given in the embodiments of the present application. In this example, a groove 70 is also provided in the resonator, there is a gap between two adjacent second electrodes 40, the groove 70 is provided in the piezoelectric layer 30, and the groove 70 is opposite to the gap, that is, it can be understood that the groove 70 communicates with the gap.

[0224] In some examples, such as Figure 18 and Figure 19, the first piezoelectric layer 301 is closer to the substrate 10 than the second piezoelectric layer 302, and the trench 70 can penetrate through the second piezoelectric layer 302 and a part of the first piezoelectric layer 301. In some other examples, such as Figure 20 , the trench 70 can penetrate through the second piezoelectric layer 302 and the first piezoelectric layer 301 until the surface of the first electrode 20.

[0225] That is, it can be understood that in the examples of the present application, the trench 70 can penetrate through a part of the piezoelectric layer 30 or the entire piezoelectric layer 30 until the surface of the first electrode 20.

[0226] By forming trenches in the multi-layer piezoelectric layer, the limitation on the piezoelectric layer can be reduced, and further, the electromechanical coupling coefficient Kt of the resonator can be increased. 2 , and, the trench 70 is also helpful for suppressing the parasitic mode of the sum frequency shift.

[0227] In some implementation structures, the deeper the trench 70, the 2 higher the electromechanical coupling coefficient Kt of the resonator. In the embodiments of the present application, such as Figure 11 , the depth h of the trench 70 can be made to satisfy: 30%H ≤ h ≤ H, where H is the thickness dimension of the piezoelectric layer 30. For example, h = 50%H, h = 60%H, h = 70%H, h = 80%H, h = 90%H or h = H.

[0228] Also, in some realizable examples, in the direction from the top surface to the bottom surface of the trench 70, the radial dimension of the trench 70 gradually decreases. For example, such as Figure 19 , the inclination angle α of the trench 70 can be: 45° ≤ α ≤ 90°. For example, in Figure 19 , the inclination angle α is about 60°, and in Figure 18 and Figure 20 , the inclination angle α is about 90°.

[0229] The inclination angle α of the trench 70 described above can be understood as: the angle between the side surface of the trench 70 and a reference plane, and the reference plane is a plane parallel to the surface of the substrate 10.

[0230] Figure 21 is a process structure diagram of a resonator having a single piezoelectric layer 30. The same as the examples of the present application above Figure 18 and Figure 20 is that: the resonator is also provided with a trench 70, there is a gap between two adjacent second electrodes 40, the trench 70 is formed in the piezoelectric layer 30, and the trench 70 communicates with the gap.

[0231] Figure 22 is obtained by using Figure 20 structure and the physical parameter limitations shown in Table 3, Figure 23It is obtained by adopting Figure 21 structure and the admittance simulation curve defined by the physical parameters shown in Table IV.

[0232]

[0233]

[0234] Table III

[0235]

[0236] Table IV

[0237] When the above table parameters are adopted, it can make Figure 20 the shown resonator and Figure 21 the frequency band range of the shown resonator be N77.

[0238] Comparing Figure 22 the admittance simulation curve of Figure 23 with the admittance simulation curve of Figure 20 the resonator of the present application example, it can be known that when the 2 resonator of the present application example is adopted, the electromechanical coupling coefficient Kt Figure 21 reaches 33.0%. When the shown single-layer piezoelectric layer is adopted, the electromechanical coupling coefficient Kt 2 is 24.2%. Obviously, when grooves are formed in the piezoelectric layer and a multi-layer piezoelectric layer with opposite polarities is included, the electromechanical coupling coefficient Kt 2 can be improved.

[0239] The resonant frequency of the Figure 20 resonator of the present application example is increased from 3.35 GHz to 3.81 GHz compared with the resonant frequency of the Figure 21 resonator.

[0240] Continuing to refer to Figure 22 , in this admittance simulation curve, near the resonant point of the SH1 main resonance mode and near the anti-resonant point of the SH1 main resonance mode, the S0 longitudinal wave hybrid mode excitation is effectively suppressed. In the admittance simulation curve of the resonator shown in Figure 23 , near the resonant point of the SH1 main resonance mode and near the anti-resonant point of the SH1 main resonance mode, a relatively large S0 longitudinal wave hybrid mode is excited.

[0241] Figure 24 It is the admittance simulation curve obtained by adopting Figure 20 structure and the physical parameters shown in Table V. Figure 25 It is the admittance simulation curve obtained by adopting Figure 21 structure and the physical parameters shown in Table VI.

[0242]

[0243] Table 5

[0244]

[0245] Table 6

[0246] When the above table parameters are adopted, it is possible to make Figure 20 the shown resonator and Figure 21 the frequency band range of the shown resonator be N79.

[0247] Comparing Figure 24 the admittance simulation curve of Figure 25 and the admittance simulation curve of Figure 20 the resonator, it can be known that when the resonator of the example of the present application is adopted, the electromechanical coupling coefficient Kt 2 reaches 39.3%. When a single piezoelectric layer shown in Figure 21 is adopted, the electromechanical coupling coefficient Kt 2 is 33.0%. Obviously, when grooves are formed in the piezoelectric layer and a plurality of piezoelectric layers with opposite polarities are included, the electromechanical coupling coefficient Kt 2 can be improved.

[0248] The resonant frequency in the resonator of the example of the present application, compared with Figure 20 the resonant frequency of the resonator, is increased from 4.02 GHz to 4.32 GHz. Figure 21

[0249] The embodiment of the present application also provides a preparation method of a resonator including a plurality of piezoelectric layers. For example Figure 26 Figure 26 exemplarily shows a flow block diagram of the preparation method of the resonator.

[0250] The preparation method includes:[[]]

[0251] Step S1: Fabricate a first electrode on a substrate;

[0252] Step S2: Fabricate a stacked first piezoelectric layer and a second piezoelectric layer on the first electrode, and fabricate a plurality of second electrodes on the second piezoelectric layer. The plurality of second electrodes are arranged side by side in a first direction; wherein, the piezoelectric material of the first piezoelectric layer has a first piezoelectric tensor component e 34 and the piezoelectric material of the second piezoelectric layer has a second piezoelectric tensor component e 34 The first piezoelectric tensor component e 34 and the second piezoelectric tensor component e 34 are opposite.

[0253] For example Figures 27A to 27F shows the process structure diagram corresponding to each step when fabricating a solid substrate piezoelectric thin film resonator.

[0254] See Figure 27A ​​, a first electrode 20 is formed on one side of the first piezoelectric wafer, and a dielectric layer 50 is formed on the first electrode 20.

[0255] See Figure 27B , the first piezoelectric wafer including the first electrode 20 and the dielectric layer 50 is bonded to the substrate 10.

[0256] See Figure 27C , the first piezoelectric wafer can be thinned by ion implantation cutting or Chemical-mechanical polishing (CMP) to a target thickness to form a first piezoelectric layer.

[0257] See Figure 27D , bond the second piezoelectric wafer to Figure 27C the first piezoelectric layer in

[0258] See Figure 27E , the second piezoelectric wafer can be thinned by ion implantation cutting or Chemical-mechanical polishing (CMP) to a target thickness to form a second piezoelectric layer.

[0259] See Figure 27F , a plurality of second electrodes arranged in parallel are formed on the second piezoelectric layer. Thus, a solid substrate piezoelectric thin film resonator is fabricated.

[0260] The first electrode can be made of any possible conductive metal (including but not limited to Al, Cu, W, Mo, Ru, Pt, etc.), or a conductive metal with a high acoustic impedance can be selected (including but not limited to W, Ru, Mo, Pt, etc.). These metals with high acoustic impedance help increase the electromechanical coupling coefficient and improve the quality factor Q, further enhancing the performance of the resonator.

[0261] The second electrode can be made of any possible conductive metal (including but not limited to Al, Cu, W, Mo, Ru, Pt, etc.). The first electrode 20 and the second electrode 40 can be made of the same conductive metal or different conductive metals.

[0262] The materials of the first piezoelectric layer and the second piezoelectric layer include at least one combination of a combination of niobium and lithium and a combination of tantalum and lithium.

[0263] In some examples, more layers of piezoelectric layers can also be fabricated.

[0264] In some other examples, trenches can be formed at positions corresponding to the gaps between two adjacent second electrodes in the piezoelectric layer. These trenches can penetrate the entire piezoelectric layer or only a part of the piezoelectric layer. The trenches are used to increase the electromechanical coupling coefficient or suppress parasitic hybrid modes.

[0265] Solid substrate piezoelectric thin film resonators or cavity-type suspended piezoelectric thin film resonators as described above can be used as sensors, such as temperature sensors, humidity sensors, pressure sensors, etc. Alternatively, they can also be used as delay line devices and applied to various high-frequency signal processing such as 100 MHz - 30 GHz.

[0266] Furthermore, the cavity-type suspended piezoelectric thin film resonators or solid substrate piezoelectric thin film resonators as described above can be Figure 28 electrically connected in a trapezoidal structure as shown to form a filter for radio frequency communication. In the filter, there can be resonators connected in series or in parallel. The resonant frequency of the parallel resonators can be lower than that of the series resonators.

[0267] Figure 28 In an example, it includes resonator 400, resonator 410, resonator 420, resonator 430, and resonator 440. Resonators 400, 410, and 420 are series resonators, and resonators 430 and 440 are parallel resonators. At least one of resonators 400 to 440 can be the resonator described in the above embodiments.

[0268] In some examples, as Figure 29 , Figure 29 shows the relationship between the admittance curves of the resonators of the trapezoidal filter and the transmission loss curve of the filter. As shown in Figure 28 , the resonant points of the series resonators (such as resonators 400, 410, and 420) and the anti-resonant points of the parallel resonators (such as resonators 430 and 440) are located within the passband frequency band to form the passband of the filter. The anti-resonant points of the series resonators (such as resonators 400, 410, and 420) are located on the high-frequency side outside the passband, and the resonant points of the parallel resonators (such as resonators 430 and 440) are located on the low-frequency side outside the passband. Thus, the filter features high roll-off and high out-of-band rejection. Figure 29

[0269] In the description of this specification, specific features, structures, materials, or characteristics can be combined in a suitable manner in any one or more embodiments or examples.

[0270] ​As described above, it is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed by this application can easily think of changes or substitutions, which should all be covered within the protection scope of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claimed rights.

Claims

1. A resonator, characterized in that, comprising: a substrate; a first electrode, a multi-layer piezoelectric layer, and a plurality of second electrodes, the first electrode, the multi-layer piezoelectric layer, and the plurality of second electrodes are disposed on the substrate, the multi-layer piezoelectric layer has a first side and a second side, the plurality of second electrodes are located on the first side and are arranged side by side in a first direction, the first electrode is located on the second side, the first side faces away from the substrate, and the second side faces the substrate; the multi-layer piezoelectric layer includes a first piezoelectric layer and a second piezoelectric layer arranged in a stacked manner; The piezoelectric material of the first piezoelectric layer has a first piezoelectric tensor component e 34 , and the piezoelectric material of the second piezoelectric layer has a second piezoelectric tensor component e 34 . The first piezoelectric tensor component e 34 is opposite to the second piezoelectric tensor component e 34 .

2. The resonator according to claim 1, characterized in that, there is a gap between two adjacent second electrodes; a groove is provided at a position of the multi-layer piezoelectric layer opposite to the gap, and the groove communicates with the gap.

3. The resonator according to claim 2, characterized in that, for the thickness dimension H of the multi-layer piezoelectric layer and the depth dimension h of the groove, 30%H ≤ h ≤ H.

4. The resonator according to claim 2 or 3, characterized in that, the first piezoelectric layer is disposed closer to the substrate than the second piezoelectric layer; the second piezoelectric layer has a top surface away from the first piezoelectric layer, the first piezoelectric layer has a bottom surface away from the second piezoelectric layer, and the groove penetrates through the top surface and the bottom surface.

5. The resonator according to any one of claims 1-4, characterized in that, for the thickness dimension S1 of the second electrode and the thickness dimension H of the multi-layer piezoelectric layer, S1 / H ≤ 0.

35.

6. The resonator according to any one of claims 1-5, characterized in that, for the thickness dimension S2 of the first electrode and the thickness dimension H of the multi-layer piezoelectric layer, S2 / H ≤ 0.

35.

7. The resonator according to any one of claims 1-6, characterized in that, the resonator further includes: a first bus bar and a second bus bar; one of every two adjacent second electrodes among the plurality of second electrodes is a first interdigital electrode, and the other is a second interdigital electrode; the first interdigital electrode and the second interdigital electrode are spaced apart in the first direction; the plurality of first interdigital electrodes among the plurality of second electrodes are connected by the first bus bar, and the plurality of second interdigital electrodes among the plurality of second electrodes are connected by the second bus bar; the finger pitch P and the thickness dimension H of the multi-layer piezoelectric layer satisfy: P / H ≥ 1; the width dimension of each first interdigital electrode is t1, the distance between every two adjacent first interdigital electrodes and second interdigital electrodes is t2, and the finger pitch P = t1 + t2, and the width dimension is a dimension parallel to the surface of the substrate and perpendicular to the extending direction of the first interdigital electrode.

8. The resonator according to any one of claims 1-7, characterized in that, based on applying a voltage to the plurality of second electrodes, the resonator is used to excite the multi-layer piezoelectric layer to generate a first resonance mode, and the vibration direction of the first resonance mode is parallel to the extending direction of the second electrode.

9. The resonator according to any one of claims 1-8, characterized in that, The electromechanical coupling coefficient Kt of the resonator 2 ≥ 24%.

10. The resonator according to any one of claims 1-9, characterized in that, the piezoelectric materials of the first piezoelectric layer and the second piezoelectric layer include at least one combination of a combination of niobium and lithium and a combination of tantalum and lithium.

11. The resonator according to any one of claims 1-10, characterized in that, the first surface and the second surface of the first electrode face each other, the second surface is closer to the substrate than the first surface, and the second surface of the first electrode is completely disposed on the substrate.

12. The resonator according to any one of claims 1-11, characterized in that, The piezoelectric tensor components e 31 、e 32 、e 33 、e 14 、e 24 、e 15 、e 25 、e 36 of the piezoelectric material of the first piezoelectric layer are the same as the piezoelectric tensor components e 31 、e 32 、e 33 、e 14 、e 24 、e 15 、e 25 、e 36 corresponding to the piezoelectric material of the second piezoelectric layer; The piezoelectric tensor components e 11 of the piezoelectric material of the first piezoelectric layer, e 12 , e 13 , e 16 , e 21 , e 22 , e 23 , e 26 , e 35 , are opposite to the piezoelectric tensor components e 11 of the piezoelectric material of the second piezoelectric layer, e 12 , e 13 , e 16 , e 21 , e 22 , e 23 , e 26 , e 35 .

13. The resonator according to any one of claims 1-11, characterized in that, The piezoelectric tensor components e 11 、e 12 、e 13 、e 14 、e 25 、e 35 、e 26 、e 36 of the piezoelectric material of the first piezoelectric layer are the same as the piezoelectric tensor components e 11 、e 12 、e 13 、e 14 、e 25 、e 35 、e 26 、e 36 corresponding to the piezoelectric material of the second piezoelectric layer; The piezoelectric tensor components e 15 、e 16 、e 21 、e 22 、e 23 、e 24 、e 31 、e 32 、e 33 of the piezoelectric material of the first piezoelectric layer are opposite to the piezoelectric tensor components e 15 、e 16 、e 21 、e 22 、e 23 、e 24 、e 31 、e 32 、e 33 of the piezoelectric material corresponding to the second piezoelectric layer.

14. The resonator according to any one of claims 1-13, characterized in that, the first piezoelectric layer and the second piezoelectric layer are adjacent layers.

15. The resonator according to any one of claims 1-14, characterized in that, the polarities of the first piezoelectric layer and the second piezoelectric layer are opposite.

16. The resonator according to any one of claims 1-15, characterized in that, the Euler angles of the crystal of the piezoelectric material of the first piezoelectric layer are (0°, 90°, 0°), and the Euler angles of the crystal of the piezoelectric material of the second piezoelectric layer are (0°, 90°, 180°), or, the Euler angles of the crystal of the piezoelectric material of the first piezoelectric layer are (0°, 270°, 0°), and the Euler angles of the crystal of the piezoelectric material of the second piezoelectric layer are (0°, 270°, 180°), or, the Euler angles of the crystal of the piezoelectric material of the first piezoelectric layer are (90°, 90°, 210°), and the Euler angles of the crystal of the piezoelectric material of the second piezoelectric layer are (90°, 90°, 30°).

17. A filter, characterized in that, comprising: a plurality of electrically connected resonators, at least one of the plurality of resonators being the resonator according to any one of claims 1-16.

18. An electronic device, characterized in that, comprising: an amplifier; the resonator according to any one of claims 1-16, or the filter according to claim 17, the resonator or the filter being electrically connected to the amplifier.

19. A method for manufacturing a resonator, characterized in that, comprising: forming a first electrode on a substrate; forming a stacked first piezoelectric layer and second piezoelectric layer on the first electrode, and forming a plurality of second electrodes on the second piezoelectric layer, the plurality of second electrodes being arranged side by side in a first direction; Among them, the piezoelectric material of the first piezoelectric layer has a first piezoelectric tensor component e 34 , and the piezoelectric material of the second piezoelectric layer has a second piezoelectric tensor component e 34 , and the first piezoelectric tensor component e 34 is opposite to the second piezoelectric tensor component e 34 .

20. The method for manufacturing a resonator according to claim 19, characterized in that, forming the first electrode on the substrate, forming the stacked first piezoelectric layer and the second piezoelectric layer on the first electrode, and forming the plurality of second electrodes on the second piezoelectric layer, comprising: forming a first electrode on one side of a first piezoelectric wafer, bonding the substrate to the first piezoelectric wafer, thinning the first piezoelectric wafer, and forming the first piezoelectric layer, the first electrode being located between the first piezoelectric layer and the substrate; Bond the second piezoelectric wafer to the first piezoelectric wafer, thin the second piezoelectric wafer, and obtain a stacked first piezoelectric layer and second piezoelectric layer; Form a plurality of second electrodes on the second piezoelectric layer.

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