Multi-coefficient coupled mode-based surface acoustic wave resonator and manufacturing method therefor

Abstract

Provided in the present disclosure are a multi-coefficient coupled mode-based surface acoustic wave resonator and a manufacturing method therefor, which can be applied to the technical field of resonators. The multi-coefficient coupled mode-based surface acoustic wave resonator comprises a substrate; a piezoelectric layer arranged on the substrate, the tangential direction of the piezoelectric layer being a Z tangential direction, a piezoelectric coefficient matrix that corresponds to the piezoelectric layer at least comprising a non-zero first piezoelectric coefficient e15 and second piezoelectric coefficient e16 and, under the action of a transverse electric field and on the basis of the first piezoelectric coefficient e15 and the second piezoelectric coefficient e16, the coupled mode of the piezoelectric layer being excited; and at least two interdigital electrodes arranged on the piezoelectric layer, the ratio of the center distance of the two adjacent interdigital electrodes to the thickness of the piezoelectric layer being 0.25-5, and the ratio of the thickness of each interdigital electrode to the thickness of the piezoelectric layer being less than 0.5.

Description

Surface acoustic wave resonator based on multi-coefficient coupled mode and preparation method thereof TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of resonators, and in particular to a surface acoustic wave resonator based on multi-coefficient coupled mode and a preparation method thereof. BACKGROUND

[0002] With the advent of the 5G / 6G era, the Internet of Things and artificial intelligence are rapidly developing, and the demand for improving data transmission capacity is increasing sharply. The radio frequency filter used in mobile communication is a core component in the radio frequency system chip, and its performance will directly affect the communication quality of the radio frequency system chip. The surface acoustic wave (SAW) resonator has excellent advantages such as small size, low cost, simple process, and stable performance, and has been widely used in the radio frequency (RF) industry.

[0003] The electromechanical coupling coefficient (k 2 ) is a key indicator for measuring the performance of filters and resonators. Therefore, it is crucial to realize a resonator with a large electromechanical coupling coefficient at a frequency higher than 3GHz for realizing a large-bandwidth filter. However, in the related art, the electromechanical coupling coefficient of the surface acoustic wave resonator is usually small, which cannot meet the frequency and bandwidth requirements of the 5G-NR frequency band.

[0004] SUMMARY

[0005] In view of the above problems, the present disclosure provides a surface acoustic wave resonator based on multi-coefficient coupled mode and a preparation method thereof.

[0006] According to a first aspect of the present disclosure, a surface acoustic wave resonator based on multi-coefficient coupled mode is provided, comprising: a substrate; a piezoelectric layer disposed on the substrate, wherein the tangential direction of the piezoelectric layer is Z-cut, and the piezoelectric coefficient matrix corresponding to the piezoelectric layer includes at least a non-zero first piezoelectric coefficient e 15 and a second piezoelectric coefficient e 16 Under the action of a transverse electric field, the piezoelectric layer is excited to a coupled mode based on the first piezoelectric coefficient e 15 and the second piezoelectric coefficient e 16 ; at least two interdigital electrodes disposed on the piezoelectric layer, wherein the ratio of the center distance between adjacent two interdigital electrodes to the thickness of the piezoelectric layer is 0.25-5, and the ratio of the thickness of the interdigital electrode to the thickness of the piezoelectric layer is less than 0.5.

[0007] According to an embodiment of the present disclosure, the thickness of the piezoelectric layer is 10nm-10um.

[0008] According to an embodiment of the present disclosure, the thickness of the interdigital electrode is 1 nm-400 nm.

[0009] According to an embodiment of the present disclosure, the ratio of the width of the interdigital electrode to the center-to-center spacing of two adjacent interdigital electrodes is an electrode duty cycle, wherein the electrode duty cycle is 0.2-0.8.

[0010] According to an embodiment of the present disclosure, the length of the interdigital electrode is 1 um-500 um; and the number of the interdigital electrodes is 2-500.

[0011] According to an embodiment of the present disclosure, the material of the interdigital electrode comprises one of gold, silver, copper, aluminum, molybdenum, chromium, nickel, platinum, or an alloy of titanium gold, titanium aluminum, titanium copper, chromium gold, chromium aluminum, chromium copper; the material of the substrate comprises one of silicon, silicon and silicon dioxide, sapphire, gallium nitride, silicon carbide; and the material of the piezoelectric layer comprises one of lithium niobate, lithium tantalate, or a composite layer material of lithium niobate, aluminum nitride, scandium-doped aluminum nitride, lithium tantalate, zinc oxide.

[0012] According to an embodiment of the present disclosure, the surface acoustic wave resonator further comprises a first temperature compensation layer disposed between the substrate and the piezoelectric layer.

[0013] According to an embodiment of the present disclosure, the surface acoustic wave resonator further comprises a second temperature compensation layer disposed on the interdigital electrode.

[0014] According to an embodiment of the present disclosure, the materials of the first temperature compensation layer and the second temperature compensation layer are both silicon dioxide.

[0015] A second aspect of the present disclosure provides a preparation method of a surface acoustic wave resonator based on a multi-coefficient coupled mode, applied to the surface acoustic wave resonator based on the multi-coefficient coupled mode, comprising: forming a piezoelectric layer on a substrate, wherein the tangential direction of the piezoelectric layer is Z tangential direction, and a piezoelectric coefficient matrix corresponding to the piezoelectric layer at least includes a non-zero first piezoelectric coefficient e 15 and a second piezoelectric coefficient e 16 Under the action of a transverse electric field, the piezoelectric layer is excited to a coupled mode based on the first piezoelectric coefficient e 15 and the second piezoelectric coefficient e 16 ; forming at least two interdigital electrodes on the piezoelectric layer, wherein the ratio of the center-to-center spacing of two adjacent interdigital electrodes to the thickness of the piezoelectric layer is 0.25-5, and the ratio of the thickness of the interdigital electrode to the thickness of the piezoelectric layer is less than 0.5.

[0016] The surface acoustic wave resonator based on the multi-coefficient coupling mode provided by the embodiments of the present disclosure changes the distribution of the transverse electric field generated by at least two interdigital electrodes by designing the center spacing of the adjacent two interdigital electrodes and the ratio of the thickness of the interdigital electrode to the thickness of the piezoelectric layer. Wherein, since the ratio of the center spacing of the adjacent two interdigital electrodes to the thickness of the piezoelectric layer is 0.25-5, and the ratio of the thickness of the interdigital electrode to the thickness of the piezoelectric layer is less than 0.5, the transverse electric field generated by at least two interdigital electrodes can excite the coupling of at least two transverse waves generated by the piezoelectric layer with tangential direction being Z tangential direction, so as to realize the high electromechanical coupling coefficient acoustic wave resonator structure with electromechanical coupling coefficient exceeding 10%, which is far more than the traditional FBAR resonator, and meets the frequency and bandwidth requirements of 5G-NR frequency band. At the same time, the ratio of the center spacing of the adjacent two interdigital electrodes to the thickness of the piezoelectric layer and the ratio of the thickness of the interdigital electrode to the thickness of the piezoelectric layer are small, which can limit the transverse electric field generated by the interdigital electrode in the piezoelectric layer, so that the vibration mainly occurs in the piezoelectric layer, thereby limiting the acoustic wave energy in the piezoelectric layer, reducing the energy leakage, and improving the quality factor (Q). BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings are used to better understand the present scheme and do not constitute a limitation on the present disclosure. Among them:

[0018] FIG. 1 schematically shows a cross-sectional view of a surface acoustic wave resonator based on a multi-coefficient coupling mode according to an embodiment of the present disclosure;

[0019] FIG. 2 schematically shows a cross-sectional view of a surface acoustic wave resonator based on a multi-coefficient coupling mode according to another embodiment of the present disclosure;

[0020] FIG. 3 schematically shows a cross-sectional view of a surface acoustic wave resonator based on a multi-coefficient coupling mode according to still another embodiment of the present disclosure;

[0021] FIG. 4 schematically shows a three-dimensional simulation vibration displacement diagram of a surface acoustic wave resonator based on a multi-coefficient coupling mode according to an embodiment of the present disclosure;

[0022] FIG. 5A schematically shows a conductance response diagram of a surface acoustic wave resonator based on a multi-coefficient coupling mode according to an embodiment of the present disclosure;

[0023] FIG. 5B schematically shows a phase diagram of a surface acoustic wave resonator based on a multi-coefficient coupling mode according to an embodiment of the present disclosure;

[0024] FIG. 6A schematically shows a three-dimensional simulation performance diagram of a surface acoustic wave resonator when the piezoelectric coefficient matrix corresponding to the piezoelectric layer only includes a non-zero first piezoelectric coefficient e 15

[0025] FIG. 6B schematically shows a three-dimensional simulation performance diagram of a surface acoustic wave resonator when the piezoelectric coefficient matrix corresponding to the piezoelectric layer only includes a non-zero first piezoelectric coefficient e 15 ​a three-dimensional simulation vibration displacement diagram of the surface acoustic wave resonator in the case that the piezoelectric coefficient matrix corresponding to the piezoelectric layer only includes a non-zero first piezoelectric coefficient e

[0026] FIG. 7A schematically shows a three-dimensional simulation vibration displacement diagram of the surface acoustic wave resonator in the case that the piezoelectric coefficient matrix corresponding to the piezoelectric layer only includes a non-zero second piezoelectric coefficient e 16 a three-dimensional simulation performance diagram of the surface acoustic wave resonator in the case that the piezoelectric coefficient matrix corresponding to the piezoelectric layer only includes a non-zero first piezoelectric coefficient e

[0027] FIG. 7B schematically shows a three-dimensional simulation vibration displacement diagram of the surface acoustic wave resonator in the case that the piezoelectric coefficient matrix corresponding to the piezoelectric layer only includes a non-zero second piezoelectric coefficient e 16 a three-dimensional simulation performance diagram of the surface acoustic wave resonator in the case that the piezoelectric coefficient matrix corresponding to the piezoelectric layer only includes a non-zero first piezoelectric coefficient e

[0028] FIG. 8 schematically shows a flowchart of a preparation method of a surface acoustic wave resonator based on a multi-coefficient coupled mode according to an embodiment of the present disclosure;

[0029] FIG. 9A schematically shows a preparation method of a surface acoustic wave resonator based on a multi-coefficient coupled mode according to an embodiment of the present disclosure, a cross-sectional view of a surface acoustic wave resonator based on a multi-coefficient coupled mode including a substrate and a piezoelectric layer prepared by the preparation method;

[0030] FIG. 9B schematically shows a preparation method of a surface acoustic wave resonator based on a multi-coefficient coupled mode according to an embodiment of the present disclosure, a cross-sectional view of a surface acoustic wave resonator based on a multi-coefficient coupled mode including an electron beam exposure machine photoresist prepared by the preparation method;

[0031] FIG. 9C schematically shows a preparation method of a surface acoustic wave resonator based on a multi-coefficient coupled mode according to an embodiment of the present disclosure, a cross-sectional view of a surface acoustic wave resonator based on a multi-coefficient coupled mode including an electron beam exposure machine photoresist prepared by the preparation method;

[0032] FIG. 9D schematically shows a preparation method of a surface acoustic wave resonator based on a multi-coefficient coupled mode according to an embodiment of the present disclosure, a cross-sectional view of a surface acoustic wave resonator based on a multi-coefficient coupled mode including an interdigital electrode prepared by the preparation method;

[0033] FIG. 9E schematically shows a preparation method of a surface acoustic wave resonator based on a multi-coefficient coupled mode according to an embodiment of the present disclosure, a cross-sectional view of a surface acoustic wave resonator based on a multi-coefficient coupled mode including an ultraviolet photoresist prepared by the preparation method;

[0034] FIG. 9F schematically shows a preparation method of a surface acoustic wave resonator based on a multi-coefficient coupled mode according to an embodiment of the present disclosure, a cross-sectional view of a surface acoustic wave resonator based on a multi-coefficient coupled mode including an ultraviolet photoresist prepared by the preparation method; and

[0035] FIG. 9G schematically shows a preparation method of a multi-coefficient coupled mode based surface acoustic wave resonator according to an embodiment of the present disclosure, a cross-sectional view of the prepared multi-coefficient coupled mode based surface acoustic wave resonator including a test electrode. DETAILED DESCRIPTION

[0036] To make the objects, technical solutions, and advantages of the embodiments of the present disclosure clearer, the following will be combined with the accompanying drawings for the embodiments of the present disclosure to make a clear and complete description of the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all. Based on the described embodiments of the present disclosure, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present disclosure. It should be noted that throughout the drawings, the same elements are denoted by the same or similar reference numerals. In the following description, some specific embodiments are only for the purpose of description, and should not be understood as any limitation on the present disclosure, but only as examples of the embodiments of the present disclosure. When it may cause confusion to the understanding of the present disclosure, the conventional structure or configuration will be omitted. It should be noted that the shape and size of the components in the drawings do not reflect the true size and ratio, but only illustrate the content of the embodiments of the present disclosure.

[0037] Unless otherwise defined, technical terms or scientific terms used in the embodiments of the present disclosure should be understood as the common meanings to those skilled in the art. The terms “first”, “second”, and similar terms used in the embodiments of the present disclosure do not denote any order, quantity, or importance, but are only used to distinguish different constituent parts.

[0038] In the case of using expressions similar to “at least one of A, B, and C, etc.”, it should be generally interpreted as including one or more of the listed items from the disclosure (e.g., “a system having at least one of A, B, and C” should be interpreted to include a system having A alone, a system having B alone, a system having C alone, a system having both A and B, a system having both A and C, a system having both B and C, and / or a system having A, B, and C, etc.).

[0039] Before entering the 5G / 6G era, in the related communication technology, the mobile communication traditional working frequency band is mainly concentrated below 3 GHz, which makes the spectrum resource very crowded, while the available spectrum resource is rich in high frequency band (such as millimeter wave, centimeter wave frequency band), which can effectively alleviate the current situation of spectrum resource shortage, support the demand of 5G capacity and transmission rate, etc. As a core component in the radio frequency system chip, the radio frequency filter plays an important role in selecting the input signal, improving the signal-to-noise ratio, avoiding spectrum growth, and the process of duplex transmission (reception), and its performance will directly affect the quality of the radio frequency system chip.

[0040] Electromechanical coupling coefficient (k 2) is a key indicator to measure the performance of filters and resonators. Higher electromechanical coupling coefficient can make the filter have a large enough passband range, so as to have the ability to transmit a larger amount of data. Therefore, the resonator with large electromechanical coupling coefficient at a frequency higher than 3 GHz is the key to realize a large bandwidth filter.

[0041] The surface acoustic wave resonator has been widely used in the radio frequency industry due to its small volume, low cost, simple process, stable performance and other excellent advantages. The commonly used piezoelectric materials of the surface acoustic wave resonator include aluminum nitride (AlN), scandium-doped aluminum nitride (AlScN), PZT, lithium niobate (LiNbO3 / LN), lithium tantalate LiTaO3 (LT), etc. Among them, lithium niobate and lithium tantalate materials have attracted great attention due to their high electromechanical coupling coefficient (k 2 ) and quality factor (Q). However, the phase velocity (v p ) of the traditional bulk lithium niobate and lithium tantalate materials is limited, and the electromechanical coupling coefficient is small, which is difficult to meet the frequency and bandwidth requirements of the 5G-NR frequency band.

[0042] To solve the above problems, the present disclosure provides a surface acoustic wave resonator based on a multi-coefficient coupling mode and a preparation method thereof, which can be applied to the technical field of resonators.

[0043] FIG. 1 schematically shows a sectional view of a surface acoustic wave resonator based on a multi-coefficient coupling mode according to an embodiment of the present disclosure.

[0044] As shown in FIG. 1, the surface acoustic wave resonator based on the multi-coefficient coupling mode includes a substrate 1, a piezoelectric layer 2, and at least two interdigital electrodes 3.

[0045] In FIG. 1, the piezoelectric layer 2 is disposed on the substrate 1. The tangential direction of the piezoelectric layer 2 is the Z tangential direction, and the piezoelectric coefficient matrix corresponding to the piezoelectric layer includes at least a non-zero first piezoelectric coefficient e 15 and a second piezoelectric coefficient e 16 Under the action of the transverse electric field, the piezoelectric layer 2 is excited to couple the mode based on the first piezoelectric coefficient e 15 and the second piezoelectric coefficient e 16

[0046] For example, the piezoelectric layer includes a piezoelectric crystal, and the tangential direction of the piezoelectric crystal is the Z tangential direction.

[0047] According to an embodiment of the present disclosure, the piezoelectric coefficient (e xy ), the relative dielectric constant (ε xx ), and the elastic coefficient (c yy ) of the piezoelectric layer determine the electromechanical coupling coefficient (k 2 ) of the surface acoustic wave resonator, and different piezoelectric coefficients can excite different vibration modes.

[0048] ​For example, the piezoelectric coefficient matrix can be a 3x6 matrix, the first piezoelectric coefficient can be e 15 , the second piezoelectric coefficient can be e 16 . Under the action of a transverse electric field, based on the first piezoelectric coefficient e 15 , the piezoelectric layer is excited to a vertical shear mode, i.e., an SV (Shear Vertical) mode. Under the action of a transverse electric field, based on the second piezoelectric coefficient e 16 , the piezoelectric layer is excited to a horizontal shear mode, i.e., an SH (Shear Horizontal) mode.

[0049] At least two interdigital electrodes 3 are arranged on the piezoelectric layer 2. The ratio of the center distance between adjacent two interdigital electrodes 3 to the thickness of the piezoelectric layer 2 is 0.25-5, and the ratio of the thickness of the interdigital electrode 3 to the thickness of the piezoelectric layer is less than 0.5.

[0050] For example, the ratio of the center distance between adjacent two interdigital electrodes 3 to the thickness of the piezoelectric layer 2 can be 0.25, 0.3, 0.5, 0.8, 1, 1.5, 2, 3.5, 4, 4.5, or 5, etc.

[0051] For example, the ratio of the thickness of the interdigital electrode 3 to the thickness of the piezoelectric layer can be 0.01, 0.1, 0.15, 0.2, 0.23, 0.3, 0.35, 0.4, 0.45, or 0.5, etc.

[0052] According to the embodiments of the present disclosure, the working principle of the surface acoustic wave resonator based on the multi-coefficient coupled mode provided by the embodiments of the present disclosure is as follows: a radio frequency signal is applied to the at least two interdigital electrodes 3, so that the at least two interdigital electrodes 3 generate a transverse electric field. The transverse electric field is applied to the piezoelectric layer 2, so that the piezoelectric layer 2 deforms to generate mechanical vibration by using the inverse piezoelectric effect under the action of the transverse electric field, thereby generating a transverse wave corresponding to the first piezoelectric coefficient e 15 and the second piezoelectric coefficient e 16 and coupling. The acoustic wave propagates along the surface of the piezoelectric layer 2, and when the frequency of the radio frequency signal and the period frequency of the interdigital electrode / reflection grating are consistent, the acoustic wave will be completely reflected by the interdigital electrode / reflection grating on both sides of the resonator, and finally propagate back and forth between the two interdigital electrodes / reflection gratings, forming resonance.

[0053] According to the embodiments of the present disclosure, the center distance between adjacent two interdigital electrodes 3 is 1 / 2 of the wavelength of the acoustic wave generated by the piezoelectric layer. In FIG. 1, λ is the wavelength of the acoustic wave generated by the piezoelectric layer.

[0054] According to the embodiments of the present disclosure, the at least two interdigital electrodes 3 are used to generate a transverse electric field under the action of an external radio frequency signal. The piezoelectric layer 2 is used to be excited to a mode corresponding to the first piezoelectric coefficient e 15 and the second piezoelectric coefficient e16 Corresponding coupling mode, generating at least two transverse waves and coupling, so that the surface acoustic wave resonator realizes the electromechanical coupling coefficient greater than 10% in the ultrahigh frequency band with the resonant frequency greater than 5GHz.

[0055] According to the embodiments of the present disclosure, the surface acoustic wave resonator based on the multi-coefficient coupling mode provided by the embodiments of the present disclosure changes the mass load effect of the interdigital electrode in the surface acoustic wave resonator, that is, by designing the center spacing of the adjacent two interdigital electrodes and the ratio of the thickness of the interdigital electrode to the thickness of the piezoelectric layer, the distribution of the transverse electric field generated by the at least two interdigital electrodes is changed, so that the piezoelectric layer is excited to generate at least two transverse waves coupled under the action of the transverse electric field, and a high electromechanical coupling coefficient acoustic wave resonator structure with an electromechanical coupling coefficient exceeding 10% is realized.

[0056] The surface acoustic wave resonator based on the multi-coefficient coupling mode provided by the embodiments of the present disclosure changes the distribution of the transverse electric field generated by the at least two interdigital electrodes by designing the center spacing of the adjacent two interdigital electrodes and the ratio of the thickness of the interdigital electrode to the thickness of the piezoelectric layer. Among them, since the ratio of the center spacing of the adjacent two interdigital electrodes to the thickness of the piezoelectric layer is 0.25-5, and the ratio of the thickness of the interdigital electrode to the thickness of the piezoelectric layer is less than 0.5, the transverse electric field generated by the at least two interdigital electrodes can excite the coupling of at least two transverse waves generated by the piezoelectric layer with the tangential direction being Z tangential direction, realizing a high electromechanical coupling coefficient acoustic wave resonator structure with an electromechanical coupling coefficient exceeding 10%, which is far higher than the traditional FBAR resonator, and meets the frequency and bandwidth requirements of the 5G-NR frequency band. At the same time, the ratio of the center spacing of the adjacent two interdigital electrodes to the thickness of the piezoelectric layer is small, which can limit the transverse electric field generated by the interdigital electrode in the piezoelectric layer, so that the vibration mainly occurs in the piezoelectric layer, thereby limiting the acoustic wave energy in the piezoelectric layer, reducing the energy leakage, and improving the quality factor (Q).

[0057] In FIG. 1, the thickness h LN of the piezoelectric layer 2 is 10nm-10um.

[0058] For example, the thickness h LN of the piezoelectric layer can be 10nm, 50nm, 100nm, 1000nm, 5000nm, 5500nm, 6000nm, 7000nm, 7500nm, 8000nm or 10000nm, etc.

[0059] In FIG. 1, the thickness h e of the interdigital electrode 3 is 1nm-400nm.

[0060] For example, the thickness h eIt can be 1 nm, 1.5 nm, 2 nm, 2.5 nm, 3 nm, 4 nm, 6 nm, 10 nm, 50 nm, 100 nm, 200 nm, 300 nm, 350 nm, or 400 nm, etc.

[0061] In FIG. 1, the width W of the interdigital electrode 3 is 1 nm-400 nm. e The ratio of the center distance between the adjacent two interdigital electrodes 3 to the width W of the interdigital electrode 3 is the electrode duty ratio. The electrode duty ratio is 0.2-0.8.

[0062] For example, the electrode duty ratio can be 0.2, 0.25, 0.3, 0.4, 0.45, 0.5, 0.6, 0.7, 0.75, or 0.8, etc.

[0063] In FIG. 1, the length of the interdigital electrode 3 is 1 um-500 um. The number of the interdigital electrodes 3 is 2-500.

[0064] For example, the length of the interdigital electrode 3 is 1 um, 10 um, 100 um, 200 um, 300 um, 350 um, 400 um, or 500 um. The number of the interdigital electrodes 3 is 2, 6, 10, 50, 100, 200, 300, 400, or 500.

[0065] In FIG. 1, the material of the interdigital electrode 3 includes one of gold, silver, copper, aluminum, molybdenum, chromium, nickel, platinum, or an alloy composed of titanium gold, titanium aluminum, titanium copper, chromium gold, chromium aluminum, chromium copper. The material of the substrate 1 includes one of silicon, silicon and silicon dioxide, sapphire, gallium nitride, silicon carbide. The material of the piezoelectric layer 2 includes one of lithium niobate, lithium tantalate, or a composite layer material of lithium niobate, aluminum nitride, scandium-doped aluminum nitride, lithium tantalate, zinc oxide.

[0066] For example, the material of the interdigital electrode 3 can be copper, the material of the substrate 1 can be silicon, and the material of the piezoelectric layer 2 can be lithium niobate.

[0067] FIG. 2 schematically shows a sectional view of a multi-coefficient coupling mode based surface acoustic wave resonator according to another embodiment of the present disclosure.

[0068] As shown in FIG. 2, the multi-coefficient coupling mode based surface acoustic wave resonator includes a substrate 1, a piezoelectric layer 2, at least two interdigital electrodes 3, and a first temperature compensation layer 4.

[0069] According to an embodiment of the present disclosure, the multi-coefficient coupling mode based surface acoustic wave resonator in FIG. 2 includes the substrate 1, the piezoelectric layer 2, and the at least two interdigital electrodes 3, which have similar structures and functions to the substrate 1, the piezoelectric layer 2, and the at least two interdigital electrodes 3 of the multi-coefficient coupling mode based surface acoustic wave resonator in FIG. 1. For the sake of simplicity, the details are not described herein.

[0070] In FIG. 2, the first temperature compensation layer 4 is arranged between the substrate 1 and the piezoelectric layer 2.

[0071] According to an embodiment of the present disclosure, the first temperature compensation layer 4 can effectively eliminate the influence of temperature change on the multi-coefficient coupled mode based surface acoustic wave resonator, and ensure the stability and accuracy of the multi-coefficient coupled mode based surface acoustic wave resonator.

[0072] FIG. 3 schematically shows a sectional view of a multi-coefficient coupled mode based surface acoustic wave resonator according to yet another embodiment of the present disclosure.

[0073] As shown in FIG. 3, the multi-coefficient coupled mode based surface acoustic wave resonator includes a substrate 1, a piezoelectric layer 2, at least two interdigital electrodes 3, and a second temperature compensation layer 5.

[0074] According to an embodiment of the present disclosure, the substrate 1, the piezoelectric layer 2, and the at least two interdigital electrodes 3 included in the multi-coefficient coupled mode based surface acoustic wave resonator in FIG. 3 have similar structures and functions to the substrate 1, the piezoelectric layer 2, and the at least two interdigital electrodes 3 included in the multi-coefficient coupled mode based surface acoustic wave resonator in FIG. 1, respectively, and for the sake of brevity, will not be described here again.

[0075] In FIG. 3, the second temperature compensation layer 5 is arranged on the interdigital electrodes 3.

[0076] According to an embodiment of the present disclosure, the second temperature compensation layer 5 can effectively eliminate the influence of temperature change on the multi-coefficient coupled mode based surface acoustic wave resonator, and ensure the stability and accuracy of the multi-coefficient coupled mode based surface acoustic wave resonator.

[0077] According to an embodiment of the present disclosure, the materials of the first temperature compensation layer 4 and the second temperature compensation layer 5 are both silicon dioxide.

[0078] According to an embodiment of the present disclosure, the multi-coefficient coupled mode based surface acoustic wave resonator can further include a substrate 1, a piezoelectric layer 2, at least two interdigital electrodes 3, a first temperature compensation layer 4, and a second temperature compensation layer 5.

[0079] According to an embodiment of the present disclosure, the multi-coefficient coupled mode based surface acoustic wave resonator provided by the embodiments of the present disclosure realizes a temperature compensation type, coupled mode based surface acoustic wave resonator structure by including a temperature compensation layer, for example, the first temperature compensation layer 4 and the second temperature compensation layer 5.

[0080] According to an embodiment of the present disclosure, for any one of the multi-coefficient coupled-mode based surface acoustic wave resonators in FIG. 1, FIG. 2, or FIG. 3, the structural parameters corresponding to the multi-coefficient coupled-mode based surface acoustic wave resonator can be, for example: the ratio of the center distance between two adjacent interdigital electrodes to the thickness of the piezoelectric layer is 1, the ratio of the thickness of the interdigital electrode to the thickness of the piezoelectric layer is 0.0875, the thickness of the piezoelectric layer is 400 nm, the thickness of the interdigital electrode is 35 nm, the width of the interdigital electrode is 200 nm, the electrode duty cycle is 0.5, the length of the interdigital electrode is 1 um, the number of interdigital electrodes is 100, the material of the interdigital electrode is gold, the material of the substrate is silicon, and the piezoelectric layer is lithium niobate.

[0081] According to an embodiment of the present disclosure, for any one of the multi-coefficient coupled-mode based surface acoustic wave resonators in FIG. 1, FIG. 2, or FIG. 3, the structural parameters corresponding to the multi-coefficient coupled-mode based surface acoustic wave resonator can be, for example: the ratio of the center distance between two adjacent interdigital electrodes to the thickness of the piezoelectric layer is 1.5, the ratio of the thickness of the interdigital electrode to the thickness of the piezoelectric layer is 0.015, the thickness of the piezoelectric layer is 6000 nm, the thickness of the interdigital electrode is 90 nm, the width of the interdigital electrode is 5400 nm, the electrode duty cycle is 0.6, the length of the interdigital electrode is 2 um, the number of interdigital electrodes is 50, the material of the interdigital electrode is copper, the material of the substrate is silicon, and the piezoelectric layer is lithium niobate.

[0082] According to an embodiment of the present disclosure, for any one of the multi-coefficient coupled-mode based surface acoustic wave resonators in FIG. 1, FIG. 2, or FIG. 3, the structural parameters corresponding to the multi-coefficient coupled-mode based surface acoustic wave resonator can be, for example: the ratio of the center distance between two adjacent interdigital electrodes to the thickness of the piezoelectric layer is 3, the ratio of the thickness of the interdigital electrode to the thickness of the piezoelectric layer is 0.04, the thickness of the piezoelectric layer is 8000 nm, the thickness of the interdigital electrode is 320 nm, the width of the interdigital electrode is 7200 nm, the electrode duty cycle is 0.3, the length of the interdigital electrode is 10 um, the number of interdigital electrodes is 30, the material of the interdigital electrode is copper, the material of the substrate is silicon, and the piezoelectric layer is lithium niobate.

[0083] According to an embodiment of the present disclosure, for any one of the multi-coefficient coupled-mode based surface acoustic wave resonators in FIG. 1, FIG. 2, or FIG. 3, the structural parameters corresponding to the multi-coefficient coupled-mode based surface acoustic wave resonator can be, for example: the ratio of the center distance between two adjacent interdigital electrodes to the thickness of the piezoelectric layer is 4, the ratio of the thickness of the interdigital electrode to the thickness of the piezoelectric layer is 0.3, the thickness of the piezoelectric layer is 1200 nm, the thickness of the interdigital electrode is 360 nm, the width of the interdigital electrode is 1200 nm, the electrode duty cycle is 0.25, the length of the interdigital electrode is 15 um, the number of interdigital electrodes is 50, the material of the interdigital electrode is copper, the material of the substrate is silicon, and the piezoelectric layer is lithium niobate.

[0084] FIG. 4 schematically shows a three-dimensional simulation vibration displacement diagram of the surface acoustic wave resonator based on the multi-coefficient coupled mode according to an embodiment of the present disclosure.

[0085] In a case where the structural parameters corresponding to the surface acoustic wave resonator based on the multi-coefficient coupled mode are that the ratio of the center distance between two adjacent interdigital electrodes to the thickness of the piezoelectric layer is 1, the ratio of the thickness of the interdigital electrode to the thickness of the piezoelectric layer is 0.0875, the thickness of the piezoelectric layer is 400 nm, the thickness of the interdigital electrode is 35 nm, the width of the interdigital electrode is 200 nm, the electrode duty cycle is 0.5, the length of the interdigital electrode is 1 um, the number of the interdigital electrode is 100, the material of the interdigital electrode is gold, the material of the substrate is silicon, the piezoelectric layer is lithium niobate, and the thickness of the first temperature compensation layer is 2 um, the surface acoustic wave resonator based on the multi-coefficient coupled mode is simulated in three dimensions, and a three-dimensional simulation vibration displacement diagram in FIG. 4 is obtained. At this time, the wavelength of the surface acoustic wave generated by the piezoelectric layer under the action of the transverse electric field is 800 nm.

[0086] It can be known from FIG. 4 that the vibration of the resonance of the piezoelectric layer included in the surface acoustic wave resonator based on the multi-coefficient coupled mode has vibrations in the Y direction, the X direction, and the Z direction, of which the vibration in the X direction is particularly strong, because the piezoelectric layer generates the transverse electric field in the X direction under the action of the interdigital electrode, and the piezoelectric layer has the first piezoelectric coefficient e 15 and the second piezoelectric coefficient e 16 Under the two modes, there is displacement in the X direction. Therefore, under the action of the transverse electric field generated by at least two interdigital electrodes, the acoustic wave generated by the piezoelectric layer has the characteristics of the vertical shear surface acoustic wave (SV-SAW) and the horizontal shear surface acoustic wave (SH-SAW), which indicates that the coupling of the modes occurs.

[0087] FIG. 5A schematically shows a conductance response diagram of the surface acoustic wave resonator based on the multi-coefficient coupled mode according to an embodiment of the present disclosure. FIG. 5B schematically shows a phase diagram of the surface acoustic wave resonator based on the multi-coefficient coupled mode according to another embodiment of the present disclosure.

[0088] In a case where the structural parameters corresponding to the surface acoustic wave resonator based on the multi-coefficient coupled mode are that the ratio of the center distance between two adjacent interdigital electrodes to the thickness of the piezoelectric layer is 1, the ratio of the thickness of the interdigital electrode to the thickness of the piezoelectric layer is 0.0875, the thickness of the piezoelectric layer is 400 nm, the thickness of the interdigital electrode is 35 nm, the width of the interdigital electrode is 200 nm, the electrode duty cycle is 0.5, the length of the interdigital electrode is 1 um, the number of the interdigital electrode is 100, the material of the interdigital electrode is gold, the material of the substrate is silicon, the piezoelectric layer is lithium niobate, and the thickness of the first temperature compensation layer is 2 um, the performance of the surface acoustic wave resonator based on the multi-coefficient coupled mode is simulated, and three-dimensional simulation performance diagrams in FIG. 5A and FIG. 5B are obtained.

[0089] In Figure 5A , the abscissa is the resonant frequency, and the ordinate is the admittance Y. In Figure 5B , the abscissa is the resonant frequency, and the ordinate is the phase, i.e., Phase.

[0090] As shown in FIG5A , the resonance peak of the surface acoustic wave resonator based on the multi-coefficient coupling mode provided by the embodiment of the present disclosure is around 5.6 GHz, and the electromechanical coupling coefficient (k 2 That is, in Figure 5A ) is 10.3799%, exceeding 10%. The electromechanical coupling coefficient far exceeds that of traditional FBAR resonators, meeting the frequency and bandwidth requirements of the 5G-NR band. Figure 5B shows that at the resonant frequency, the phase shifts from +90° to -90°. In other words, the SAW resonator transitions from capacitive to inductive, achieving maximum energy conversion at the resonant frequency.

[0091] FIG. 6A schematically shows that the piezoelectric coefficient matrix corresponding to the piezoelectric layer includes only the non-zero first piezoelectric coefficient e 15 FIG6B schematically shows a three-dimensional simulation performance diagram of the surface acoustic wave resonator when the piezoelectric coefficient matrix corresponding to the piezoelectric layer only includes the non-zero first piezoelectric coefficient e 15 3D simulation vibration displacement diagram of the surface acoustic wave resonator under the condition of .

[0092] The surface acoustic wave resonators in FIG6A and FIG6B use the same set of surface acoustic wave resonator structural parameters. The surface acoustic wave resonators in FIG6A and FIG6B differ from the surface acoustic wave resonators based on multi-coefficient coupling modes in FIG5A and FIG5B in that the piezoelectric coefficient matrix corresponding to the surface acoustic wave resonator based on multi-coefficient coupling modes in FIG5A and FIG5B includes a non-zero first piezoelectric coefficient e 15 and the second piezoelectric coefficient e 16 6A and 6B, the piezoelectric coefficient matrix corresponding to the surface acoustic wave resonator includes only the non-zero first piezoelectric coefficient e 15 , and other piezoelectric coefficients are set to zero.

[0093] In FIG6A , the abscissa is the resonant frequency, and the ordinate is the admittance Y. FIG6A : FIG6A is a block diagram of a resonant frequency ...

[0094] As shown in FIG6A , the electromechanical coupling coefficient (k 2 ) is 2.67%, which is smaller than the electromechanical coupling coefficient of 10.3799% of the surface acoustic wave resonator based on the multi-coefficient coupling mode in Figure 5A, and cannot meet the frequency and bandwidth requirements of the 5G-NR band. As shown in Figure 6B, the main resonance vibration of the surface acoustic wave resonator in Figure 6B mainly occurs in the Z direction and the X direction, which is consistent with the characteristics of the vertical shear surface acoustic wave (SV-SAW), indicating that the piezoelectric coefficient e 15 It determines the vertical shear mode.

[0095] Figure 7A schematically shows a three-dimensional simulation performance diagram of a surface acoustic wave resonator in a case where a piezoelectric coefficient matrix corresponding to a piezoelectric layer only includes a non-zero second piezoelectric coefficient e 16 16 Figure 7B schematically shows a three-dimensional simulation vibration displacement diagram of a surface acoustic wave resonator in a case where a piezoelectric coefficient matrix corresponding to a piezoelectric layer only includes a non-zero second piezoelectric coefficient e

[0096] The surface acoustic wave resonators in Figures 7A and 7B use the same set of surface acoustic wave resonator structure parameters. The surface acoustic wave resonators in Figures 7A and 7B differ from the multi-coefficient coupled mode based surface acoustic wave resonator in Figures 5A and 5B in that the piezoelectric coefficient matrix corresponding to the surface acoustic wave resonator in Figures 7A and 7B only includes a non-zero second piezoelectric coefficient e 15 and a second piezoelectric coefficient e 16 , the piezoelectric coefficient matrix corresponding to the surface acoustic wave resonator in Figures 7A and 7B only includes a non-zero second piezoelectric coefficient e 16 , and other piezoelectric coefficients are assigned to zero.

[0097] In Figure 7A, the horizontal axis is the resonant frequency, and the vertical axis is the admittance Y.

[0098] As can be seen from Figure 7A, the electromechanical coupling coefficient (k 2 ) corresponding to the main resonant peak of the surface acoustic wave resonator in Figure 7A is 6.36%, which is smaller than the electromechanical coupling coefficient 10.3799% of the multi-coefficient coupled mode based surface acoustic wave resonator in Figure 5A, and cannot meet the frequency and bandwidth requirements of the 5G-NR frequency band. As can be seen from Figure 7B, the vibration of the main resonance of the surface acoustic wave resonator in Figure 7B mainly occurs in the X direction and the Y direction, which is consistent with the characteristics of the horizontal shear surface acoustic wave (SH-SAW), indicating that the piezoelectric coefficient e 16 determines the horizontal shear mode.

[0099] Based on the above multi-coefficient coupled mode based surface acoustic wave resonator, the disclosure embodiments further provide a preparation method of a multi-coefficient coupled mode based surface acoustic wave resonator.

[0100] Figure 8 schematically shows a flowchart of a preparation method of a multi-coefficient coupled mode based surface acoustic wave resonator according to an embodiment of the disclosure.

[0101] ​According to an embodiment of the present disclosure, the preparation method of the multi-coefficient coupling mode based SAW resonator in FIG. 8 can be applied to the multi-coefficient coupling mode based SAW resonator in FIG. 1, FIG. 2 or FIG. 3. The structure and function of the SAW resonator prepared by the preparation method of the multi-coefficient coupling mode based SAW resonator in FIG. 8 can refer to the description of the SAW resonator in FIG. 1, FIG. 2 or FIG. 3, and will not be repeated here for simplicity.

[0102] As shown in FIG. 8, the preparation method of the multi-coefficient coupling mode based SAW resonator of this embodiment includes operation S810 to operation S820.

[0103] In operation S810, a piezoelectric layer is formed on a substrate, wherein the tangential direction of the piezoelectric layer is the Z tangential direction, and the piezoelectric coefficient matrix corresponding to the piezoelectric layer at least includes a non-zero first piezoelectric coefficient e 15 and a second piezoelectric coefficient e 16 Under the action of a transverse electric field, the piezoelectric layer is excited to a coupling mode based on the first piezoelectric coefficient e 15 and the second piezoelectric coefficient e 16 .

[0104] In operation S820, at least two interdigital electrodes are formed on the piezoelectric layer, wherein the ratio of the center distance between adjacent two interdigital electrodes to the thickness of the piezoelectric layer is 0.25-5, and the ratio of the thickness of the interdigital electrode to the thickness of the piezoelectric layer is less than 0.5.

[0105] According to an embodiment of the present disclosure, for operation S820, forming at least two interdigital electrodes on the piezoelectric layer can include the following operations: uniformly coating the piezoelectric layer with electron beam exposure machine photoresist and drying using a hot plate; using an electron beam exposure machine to photoetch an interdigital electrode pattern on the electron beam exposure machine photoresist on the piezoelectric layer, developing after photoetching, and patterning the shape of the interdigital electrode included in the SAW resonator on the electron beam exposure machine photoresist on the piezoelectric layer; using an electron beam evaporation film deposition process to deposit a top interdigital electrode on the piezoelectric layer (wherein the material of the interdigital electrode can be Au); and then using a stripping process to remove the electron beam exposure machine photoresist around the interdigital electrode to form the interdigital electrode.

[0106] According to embodiments of the present disclosure, the preparation method of the multi-coefficient coupling mode based surface acoustic wave resonator in FIG. 8 can further include: uniformly coating the interdigital electrode with ultraviolet photoresist and drying using a hot plate; using ultraviolet lithography to lithograph the busline pattern on the ultraviolet photoresist on the piezoelectric layer, developing after lithography, and patterning the shape of the busline included in the surface acoustic wave resonator on the ultraviolet photoresist on the piezoelectric layer; depositing a top busline (wherein the material of the busline can be Au) using a magnetron sputtering film deposition process, and then using a stripping process to remove the ultraviolet photoresist around the busline to form the busline. The busline is used to test the multi-coefficient coupling mode based surface acoustic wave resonator in the test phase.

[0107] According to embodiments of the present disclosure, the preparation method of the multi-coefficient coupling mode based surface acoustic wave resonator in FIG. 8 can further include: before forming the at least two interdigital electrodes on the piezoelectric layer in operation S820, forming a first temperature compensation layer between the substrate and the piezoelectric layer. The process of forming the first temperature compensation layer can be PECVD (Plasma Enhanced Chemical Vapor Deposition), Ebeam (Electron Beam Evaporation), thermal evaporation, or Sputter (Sputtering process control).

[0108] According to embodiments of the present disclosure, the preparation method of the multi-coefficient coupling mode based surface acoustic wave resonator in FIG. 8 can further include: forming a second temperature compensation layer on the at least two interdigital electrodes. The process of forming the second temperature compensation layer can be PECVD, Ebeam, thermal evaporation, or Sputter.

[0109] According to embodiments of the present disclosure, the preparation method of the multi-coefficient coupling mode based surface acoustic wave resonator in FIG. 8 can further include: before forming the at least two interdigital electrodes on the piezoelectric layer in operation S820, forming a first temperature compensation layer between the substrate and the piezoelectric layer; after performing operation S820, forming a second temperature compensation layer on the at least two interdigital electrodes. The processes of forming the first temperature compensation layer and the second temperature compensation layer can both be PECVD, Ebeam, thermal evaporation, or Sputter.

[0110] As shown in FIG. 8, the preparation method of the surface acoustic wave resonator based on the multi-coefficient coupled mode provided in the embodiments of the present disclosure is different from the traditional FBAR (Film Bulk Acoustic Resonator, thin film cavity acoustic resonator filter) resonator. The resonator only needs to perform a photolithography process, and does not need to perform an etching process, and the process is relatively simple.

[0111] The surface acoustic wave resonator based on the multi-coefficient coupled mode obtained in each preparation step of the preparation method of the surface acoustic wave resonator based on the multi-coefficient coupled mode in FIG. 8 will be further described below based on FIGS. 9A to 9G.

[0112] FIG. 9A schematically shows a cross-sectional view of a surface acoustic wave resonator based on a multi-coefficient coupled mode prepared according to the preparation method of the surface acoustic wave resonator based on the multi-coefficient coupled mode provided in the embodiments of the present disclosure.

[0113] After the operation S810 in FIG. 8, the piezoelectric layer is formed on the substrate, and the surface acoustic wave resonator based on the multi-coefficient coupled mode in FIG. 9A is obtained.

[0114] As shown in FIG. 9A, the surface acoustic wave resonator based on the multi-coefficient coupled mode includes a substrate 1 and a piezoelectric layer 2. The substrate 1 and the piezoelectric layer 2 in FIG. 9A have similar structures and functions to the substrate 1 and the piezoelectric layer 2 in FIG. 1, respectively, and are not described herein again for simplicity.

[0115] FIG. 9B schematically shows a cross-sectional view of a surface acoustic wave resonator based on a multi-coefficient coupled mode prepared according to the preparation method of the surface acoustic wave resonator based on the multi-coefficient coupled mode provided in the embodiments of the present disclosure.

[0116] After the operation S820 in FIG. 9A, the surface acoustic wave resonator based on the multi-coefficient coupled mode in FIG. 9B is obtained after the e-beam exposure machine photoresist is uniformly coated on the piezoelectric layer and dried using a hot plate.

[0117] As shown in FIG. 9B, the surface acoustic wave resonator based on the multi-coefficient coupled mode includes a substrate 1, a piezoelectric layer 2, and an e-beam exposure machine photoresist 6.

[0118] FIG. 9C schematically shows a cross-sectional view of a surface acoustic wave resonator based on a multi-coefficient coupled mode prepared according to the preparation method of the surface acoustic wave resonator based on the multi-coefficient coupled mode provided in the embodiments of the present disclosure.

[0119] In the multi-coefficient coupling mode based surface acoustic wave resonator in FIG. 9B, the e-beam lithography photoresist on the piezoelectric layer is photoetched by using the e-beam exposure machine in operation S820, and after the photoetching is developed, the multi-coefficient coupling mode based surface acoustic wave resonator is patterned in shape of the interdigital electrode included in the surface acoustic wave resonator on the e-beam lithography photoresist on the piezoelectric layer, to obtain the multi-coefficient coupling mode based surface acoustic wave resonator in FIG. 9C.

[0120] As shown in FIG. 9C, the multi-coefficient coupling mode based surface acoustic wave resonator includes a substrate 1, a piezoelectric layer 2, and an e-beam lithography photoresist 7 patterned in shape of the interdigital electrode.

[0121] FIG. 9D schematically shows a preparation method of the multi-coefficient coupling mode based surface acoustic wave resonator according to an embodiment of the present disclosure, a cross-sectional view of the prepared multi-coefficient coupling mode based surface acoustic wave resonator including the interdigital electrode.

[0122] In the multi-coefficient coupling mode based surface acoustic wave resonator in FIG. 9C, the e-beam lithography photoresist on the piezoelectric layer is photoetched by using the e-beam exposure machine in operation S820, and after the photoetching is developed, the multi-coefficient coupling mode based surface acoustic wave resonator is patterned in shape of the interdigital electrode included in the surface acoustic wave resonator on the e-beam lithography photoresist on the piezoelectric layer, to obtain the multi-coefficient coupling mode based surface acoustic wave resonator in FIG. 9C.

[0123] As shown in FIG. 9D, the multi-coefficient coupling mode based surface acoustic wave resonator includes a substrate 1, a piezoelectric layer 2, and an interdigital electrode 3. The substrate 1, the piezoelectric layer 2, and the interdigital electrode 3 in FIG. 9D have similar structures and functions to the substrate 1, the piezoelectric layer 2, and the interdigital electrode 3 in FIG. 1 respectively, and are not described herein again for simplicity.

[0124] FIG. 9E schematically shows a preparation method of the multi-coefficient coupling mode based surface acoustic wave resonator according to an embodiment of the present disclosure, a cross-sectional view of the prepared multi-coefficient coupling mode based surface acoustic wave resonator including the ultraviolet photoresist.

[0125] In the multi-coefficient coupling mode based surface acoustic wave resonator in FIG. 9D, the e-beam lithography photoresist on the piezoelectric layer is photoetched by using the e-beam exposure machine in operation S820, and after the photoetching is developed, the multi-coefficient coupling mode based surface acoustic wave resonator is patterned in shape of the interdigital electrode included in the surface acoustic wave resonator on the e-beam lithography photoresist on the piezoelectric layer, to obtain the multi-coefficient coupling mode based surface acoustic wave resonator in FIG. 9C.

[0126] As shown in FIG. 9E, the multi-coefficient coupling mode based surface acoustic wave resonator includes a substrate 1, a piezoelectric layer 2, an interdigital electrode 3, and an ultraviolet photoresist 8.

[0127] FIG. 9F schematically shows a preparation method of the multi-coefficient coupling mode based surface acoustic wave resonator according to an embodiment of the present disclosure, a cross-sectional view of the prepared multi-coefficient coupling mode based surface acoustic wave resonator including the ultraviolet photoresist patterned in shape of the test electrode.

[0128] The multi-coefficient coupling mode based surface acoustic wave resonator in FIG. 9E, through operations, adopts ultraviolet photoresist on the piezoelectric layer to photoetch the test electrode pattern, after photoetching, develops, and after patterning the shape of the test electrode included in the surface acoustic wave resonator on the ultraviolet photoresist on the piezoelectric layer, obtains the multi-coefficient coupling mode based surface acoustic wave resonator in FIG. 9F.

[0129] As shown in FIG. 9F, the multi-coefficient coupling mode based surface acoustic wave resonator includes a substrate 1, a piezoelectric layer 2, an interdigital electrode 3, and ultraviolet photoresist 9 patterning the shape of the test electrode.

[0130] FIG. 9G schematically shows a preparation method of a multi-coefficient coupling mode based surface acoustic wave resonator provided by an embodiment of the present disclosure, a sectional view of the prepared multi-coefficient coupling mode based surface acoustic wave resonator including a test electrode.

[0131] The multi-coefficient coupling mode based surface acoustic wave resonator in FIG. 9F, through operations, adopts a magnetron sputtering film deposition process to deposit a top test electrode, and then uses a stripping process to remove the ultraviolet photoresist around the test electrode to form the test electrode, and then obtains the multi-coefficient coupling mode based surface acoustic wave resonator in FIG. 9G, and obtains the final multi-coefficient coupling mode based surface acoustic wave resonator.

[0132] As shown in FIG. 9G, the multi-coefficient coupling mode based surface acoustic wave resonator includes a substrate 1, a piezoelectric layer 2, an interdigital electrode 3, and a test electrode 10.

[0133] Those skilled in the art can understand that the features described in various embodiments and / or claims of the present disclosure can be combined and / or integrated in various combinations, even if such combinations or integrations are not explicitly described in the present disclosure. In particular, the features described in various embodiments and / or claims of the present disclosure can be combined and / or integrated in various combinations without departing from the spirit and teachings of the present disclosure. All such combinations and / or integrations fall within the scope of the present disclosure.

[0134] The above describes embodiments of the present disclosure. However, these embodiments are merely for illustrative purposes, and are not intended to limit the scope of the present disclosure. Although each embodiment is described above separately, this does not mean that the measures in each embodiment cannot be used advantageously in combination. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, which all fall within the scope of the present disclosure.

Claims

1. A surface acoustic wave resonator based on multi-coefficient coupled modes, comprising: substrate; A piezoelectric layer is provided on the substrate, wherein the tangential direction of the piezoelectric layer is the Z tangential direction, and the piezoelectric coefficient matrix corresponding to the piezoelectric layer includes at least a non-zero first piezoelectric coefficient e 15 and the second piezoelectric coefficient e 16 , under the action of the transverse electric field, based on the first piezoelectric coefficient e 15 and the second piezoelectric coefficient e 16 , the piezoelectric layer is excited into coupled modes; At least two interdigital electrodes are arranged on the piezoelectric layer, wherein the ratio of the center distance between two adjacent interdigital electrodes to the thickness of the piezoelectric layer is 0.25-5, and the ratio of the thickness of the interdigital electrodes to the thickness of the piezoelectric layer is less than 0.

5.

2. The surface acoustic wave resonator according to claim 1, wherein The thickness of the piezoelectric layer is 10 nm-10 um.

3. The surface acoustic wave resonator according to claim 1 or 2, wherein: The thickness of the interdigital electrodes is 1 nm-400 nm.

4. The surface acoustic wave resonator according to claim 3, wherein The ratio of the width of the interdigital electrode to the center distance between two adjacent interdigital electrodes is the electrode duty cycle, wherein the electrode duty cycle is 0.2-0.

8.

5. The surface acoustic wave resonator according to claim 4, wherein The length of the interdigital electrodes is 1um-500um; The number of the interdigital electrodes is 2-500.

6. The surface acoustic wave resonator according to claim 1 or 2, wherein: The material of the interdigital electrodes includes one of the following: gold, silver, copper, aluminum, molybdenum, chromium, nickel, platinum, or an alloy of titanium-gold, titanium-aluminum, titanium-copper, chromium-gold, chromium-aluminum, and chromium-copper; The material of the substrate includes one of the following: silicon, silicon and silicon dioxide, sapphire, gallium nitride, and silicon carbide; The material of the piezoelectric layer includes one of the following: lithium niobate, lithium tantalate, or a composite layer material of lithium niobate, aluminum nitride, scandium-doped aluminum nitride, lithium tantalate, and zinc oxide.

7. The surface acoustic wave resonator according to claim 1, wherein Also includes: The first temperature compensation layer is arranged between the substrate and the piezoelectric layer.

8. The surface acoustic wave resonator according to claim 1, wherein Also includes: The second temperature compensation layer is disposed on the interdigital electrodes.

9. The surface acoustic wave resonator according to claim 7 or 8, wherein: The first temperature compensation layer and the second temperature compensation layer are both made of silicon dioxide.

10. A method for preparing a surface acoustic wave resonator based on a multi-coefficient coupled mode, applied to the surface acoustic wave resonator based on a multi-coefficient coupled mode according to any one of claims 1 to 9, comprising: A piezoelectric layer is formed on a substrate, wherein the tangential direction of the piezoelectric layer is the Z tangential direction, and the piezoelectric coefficient matrix corresponding to the piezoelectric layer includes at least a non-zero first piezoelectric coefficient e 15 and the second piezoelectric coefficient e 16 , under the action of the transverse electric field, based on the first piezoelectric coefficient e 15 and the second piezoelectric coefficient e 16 , the piezoelectric layer is excited into coupled modes; At least two interdigital electrodes are formed on the piezoelectric layer, wherein the ratio of the center distance between two adjacent interdigital electrodes to the thickness of the piezoelectric layer is 0.25-5, and the ratio of the thickness of the interdigital electrodes to the thickness of the piezoelectric layer is less than 0.5.

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