Surface acoustic wave device

Abstract

The invention relates to the technical field of electronic information materials, and discloses a surface acoustic wave device which comprises a piezoelectric substrate and at least one set of interdigital transducers arranged on the piezoelectric substrate, the piezoelectric substrate comprises a substrate and a piezoelectric single crystal layer, the piezoelectric single crystal layer is arranged on the side, facing the interdigital transducers, of the substrate, and the piezoelectric single crystal layer is arranged on the side, facing the interdigital transducers, of the substrate. The piezoelectric single crystal layer comprises lithium niobate or lithium tantalate, the tangential direction of the piezoelectric single crystal layer is 100-140 degrees Y, and the substrate comprises a sapphire substrate or a silicon carbide substrate. According to the surface acoustic wave device, due to the structural parameter design based on the multilayer piezoelectric heterostructure, the ultra-high frequency of 10 GHz can be achieved, the line width of the interdigital electrode is large and is larger than the limit line width of a standard KrF photoetching technology in the field, and therefore batch preparation of the SAW device can be achieved through the standard KrF photoetching technology, and the application prospect is wide. And the cost of large-scale production of the SAW device is reduced, and the method has important value for actual production.

Description

Technical Field

[0001] This application relates to the technical field of electronic information materials, and specifically, to surface acoustic wave devices. Background Art

[0002] With the rapid development of the Internet of Things and artificial intelligence, the global data traffic has increased exponentially, prompting the development of wireless communication systems towards higher frequencies and larger bandwidths. The widespread deployment of 5G and 6G networks has made it difficult for traditional low-frequency bands to meet the requirements of high-speed transmission, ultra-low latency, and high reliability. Therefore, medium and high-frequency bands including C-band (4 GHz - 8 GHz), X-band (8 GHz - 12 GHz), and Ku-band (12 GHz - 18 GHz) have received extensive attention in the industry due to their excellent bandwidth capacity and propagation characteristics, especially in the frequency range of 8 GHz - 15 GHz.

[0003] As the frequency increases, more stringent requirements need to be met for the thermal stability and power handling capabilities of devices. Traditional piezoelectric bulk acoustic wave filters are limited by their inherent low phase velocity (V p ), and their operating frequencies are usually lower than 3 GHz. Surface Acoustic Wave (SAW) devices are electronic components that use acoustic waves propagating on the solid surface to achieve signal processing. They have the characteristics of small size, simple manufacturing process, and stable performance, and are widely used in the radio frequency field. In recent years, the research on multi-layer piezoelectric heterostructures has promoted the excitation of high-velocity surface acoustic wave modes, such as the Shear Horizontal Wave (SH) with a velocity of about 4000 m / s and the Longitudinal Leaky Surface Acoustic Wave (LLSAW) with a velocity of about 6000 m / s, which can extend the operating frequency of surface acoustic wave filters to 4 GHz - 6 GHz. Therefore, further increasing the operating frequency to meet the 5G and 6G spectrum allocation requirements has made X-band surface acoustic wave filters a current research hotspot.

[0004] It should be noted that the above statements are only used to provide background technical information related to this application, and do not necessarily constitute prior art. Summary of the Invention

[0005] In the first aspect of the present application, a surface acoustic wave device is proposed, including: a piezoelectric substrate and at least one set of interdigital transducers disposed on the piezoelectric substrate. Among them, the piezoelectric substrate includes a substrate and a piezoelectric single crystal layer, and the piezoelectric single crystal layer is disposed on one side of the substrate facing the interdigital transducers. The piezoelectric single crystal layer includes lithium niobate or lithium tantalate, the tangential direction of the piezoelectric single crystal layer is 100°-140°Y, and the substrate includes a sapphire substrate or a silicon carbide substrate.

[0006] The surface acoustic wave device (SAW device) proposed in the present application is based on a multi-layer piezoelectric heterostructure, optimizing the acoustic propagation characteristics, and successfully exciting the higher-order vertical shear mode (SV-SAW, V p ≈10km / s), realizing a new surface acoustic wave mode with a higher sound speed. Therefore, the surface acoustic wave device proposed in the present application can operate in the X-band range, and its center frequency (f c ) exceeds 10 GHz. Moreover, the structure of the surface acoustic wave device proposed in the present application is relatively simple, and the surface acoustic wave device can be prepared by a standard lithography process, which is conducive to the promotion of mass production.

[0007] In some embodiments, the acoustic wave propagation direction of the piezoelectric single crystal layer is 0°-15°X. When the acoustic wave propagation direction of the piezoelectric single crystal layer is within the foregoing range, the intrinsic electromechanical coupling coefficient is relatively large, which is conducive to realizing efficient acoustic-electric conversion.

[0008] In some embodiments, the thickness of the piezoelectric single crystal layer is 210 nm-270 nm. Thus, the SAW device of the present application can exhibit an ultra-high center frequency, excellent electromechanical coupling coefficient and quality factor as a resonator, and can exhibit low insertion loss characteristics within the target frequency band as a filter.

[0009] In some embodiments, the line width of the interdigital electrodes of the interdigital transducer is 0.18 μm-0.30 μm. When the line width of the interdigital electrodes of the interdigital transducer is within the foregoing range, the wavelength of the SAW device is 0.72 μm-1.20 μm, and it can be used as a high-performance ultra-high frequency resonator and filter.

[0010] In some embodiments, it further includes: a functional layer, and the functional layer is disposed between the substrate and the piezoelectric single crystal layer, and the functional layer includes silicon oxide. Thus, the functional layer can assist the bonding process or improve the performance of the SAW device. In the multi-layer piezoelectric heterostructure of the SAW device, a waveguide effect can be formed among the piezoelectric single crystal layer, the functional layer with a low sound speed and the substrate with a high sound speed, which can suppress the leakage of low-frequency acoustic wave energy and is conducive to exciting and generating an ultra-high frequency SV wave mode.

[0011] In some embodiments, the thickness of the functional layer is 60 nm - 120 nm. Within the aforementioned range, the functional layer and the single-crystal piezoelectric layer can form a relatively high response intensity for the target SV mode. Thereby, it is beneficial to improve the performance of the SAW device.

[0012] In some embodiments, the interdigital electrodes of the interdigital transducer include at least one of Al, Cu, Pt, and W. Thereby, the interdigital electrodes prepared from the aforementioned metals are beneficial to increasing the response frequency of the SAW in the SAW device.

[0013] In some embodiments, the thickness of the interdigital electrodes of the interdigital transducer is 30 nm - 150 nm. Thereby, the mass loading effect can be reduced, the acoustic loss can be reduced, and the insertion loss can be decreased, which is beneficial to the high-frequency application of the SAW device.

[0014] In some embodiments, it further includes: a modification layer, which is disposed between the interdigital transducer and the piezoelectric substrate, and the modification layer includes at least one of Ti, Ni, and Cr. Thereby, it is beneficial to improving the electromigration resistance of the interdigital electrodes.

[0015] In some embodiments, the thickness of the modification layer is 1 nm - 20 nm. Within the aforementioned range of the thickness of the modification layer, the modification layer can play a good auxiliary effect on the interdigital electrodes. Thereby, it is beneficial to enhancing the performance of the SAW device.

[0016] In some embodiments, the thickness of the substrate is 30 μm - 1000 μm. Within the aforementioned range of the thickness of the substrate, a SAW device with stable performance can be fabricated, and its specific thickness can be adjusted according to the application conditions. Description of the Drawings

[0017] The above and / or additional aspects and advantages of the present application will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, where:

[0018] Figure 1 is a schematic structural diagram of a surface acoustic wave device in an embodiment of the present application;

[0019] Figure 2 is a typical admittance curve diagram of a surface acoustic wave device in an embodiment of the present application;

[0020] Figure 3 is a schematic displacement distribution diagram of a high-order vertical shear wave (SV-SAW) mode in an embodiment of the present application;

[0021] Figure 4 is an admittance curve diagram of a surface acoustic wave device with different electrode materials and different wavelengths in an embodiment of the present application;

[0022] Figure 5It is the admittance and its fitting curve graph of two typical resonators in Embodiment 1 of this application;

[0023] Figure 6 It is the S 21 response curve graph of three typical X - band filters in Embodiment 2 of this application.

[0024] Description of reference numerals:

[0025] Piezoelectric single crystal layer 1; functional layer 2; substrate 3; interdigital transducer 4. Detailed implementation manners

[0026] The embodiments of this application will be described in detail below. Examples of the embodiments are shown in the drawings, but there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well - known matters are omitted and repeated descriptions of actually identical structures are omitted. This is to avoid the following description from becoming unnecessarily long and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand this application and are not intended to limit the subject matter recited in the claims.

[0027] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application; unless otherwise stated, the numerical values of the various parameters mentioned in this application can be measured by various commonly used measurement methods in the art (for example, they can be tested according to the methods given in the embodiments of this application).

[0028] The terms "comprising" and "having" and any variations thereof in the description and claims of this application are open - ended expressions, that is, including the content specified in this application, but not excluding other aspects.

[0029] In the description of this application, all the numbers disclosed herein are approximate values, whether or not the words "about" or "approximately" are used. There may be a difference of less than 10% in the numerical value of each number or a reasonable difference considered by those skilled in the art, such as a difference of 1%, 2%, 3%, 4% or 5%.

[0030] The "range" disclosed in this application is defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The ranges defined in this way can include or exclude the end values, and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 - 120 and 80 - 110 are listed for a specific parameter, ranges of 60 - 110 and 80 - 120 are also contemplated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all contemplated: 1 - 3, 1 - 4, 1 - 5, 2 - 3, 2 - 4, and 2 - 5. In this application, unless otherwise specified, the numerical range "a - b" represents an abbreviated representation of any combination of real numbers between a and b, where both a and b are real numbers. For example, the numerical range "0 - 5" means that all real numbers between "0 - 5" are fully listed herein, and "0 - 5" is only an abbreviated representation of these numerical combinations. Additionally, when stating that a certain parameter is an integer ≥2, it is equivalent to disclosing that the parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0031] Without special instructions, all implementation manners and optional implementation manners of this application can be combined with each other to form new technical solutions.

[0032] Without special instructions, all technical features and optional technical features of this application can be combined with each other to form new technical solutions.

[0033] Currently, the technical directions that can meet the requirements of high operating frequencies mainly include Cross - Sectional Bulk Acoustic Resonators (XBARs) and Lamb Wave Resonators (LWRs). Since the aforementioned technologies highly rely on the structure of the suspended piezoelectric thin film in the device, but this structure is fragile and the manufacturing process is complex, it limits the possibility of large - scale industrial application along this technical route. The methods for process improvement include reducing the line width of Inter - Digital Transducers (IDTs). However, the resolution limit of standard KrF lithography in the surface acoustic wave device industry (line width ≥0.18μm) makes it difficult for the filter frequency of surface acoustic wave devices to break through 6GHz. Although Electron Beam Lithography (EBL) can achieve a smaller line width (≤0.15μm), its high cost, long manufacturing time, and the inherently low power handling ability of ultra - fine line widths cannot meet the functional requirements and severely limit the application and large - scale production of surface acoustic wave devices that can meet high - frequency requirements. [[ID=,11]]

[0034] The surface acoustic wave device (SAW device) proposed in this application is based on a multi-layer piezoelectric heterostructure, which optimizes the acoustic propagation characteristics and successfully excites the higher-order vertical shear mode (SV-SAW, V p ≈ 10 km / s), realizing a new surface acoustic wave mode with a higher sound speed. Therefore, the surface acoustic wave device proposed in this application can operate in the X-band range, and its center frequency (f c ) exceeds 10 GHz. Moreover, the structure of the surface acoustic wave device proposed in this application is relatively simple, and the surface acoustic wave device can be prepared by a standard photolithography process, which is conducive to the promotion of mass production.

[0035] In the first aspect of this application, a surface acoustic wave device is proposed, including: a piezoelectric substrate and at least one set of interdigital transducers disposed on the piezoelectric substrate. Among them, the piezoelectric substrate includes a substrate and a piezoelectric single crystal layer, and the piezoelectric single crystal layer is disposed on one side of the substrate facing the interdigital transducers. The piezoelectric single crystal layer includes lithium niobate or lithium tantalate, the tangential direction of the piezoelectric single crystal layer is 100°-140°Y, and the substrate includes a sapphire substrate or a silicon carbide substrate.

[0036] The surface acoustic wave device proposed in this application, referring to Figure 1 , is based on a multi-layer piezoelectric heterostructure composed of an interdigital transducer 4 (IDT), a piezoelectric single crystal layer 1 of lithium niobate (LN) or lithium tantalate (LT) piezoelectric material, and a substrate 3, which may include a sapphire substrate (Sapphire) or a silicon carbide substrate (SiC), etc. The piezoelectric material converts an electrical signal into an acoustic wave signal, and a new high-frequency surface acoustic wave resonance mode of the higher-order vertical shear wave (SV-SAW) is realized by using the propagation characteristics of the acoustic wave on the surface of the medium. As Figure 2 shown, the resonance frequency of the higher-order SV-SAW mode reaches 10.04 GHz, the anti-resonance frequency reaches 10.32 GHz, and there is almost no parasitic mode interference in the large range of 5 GHz - 14 GHz, which indicates that the surface acoustic wave device proposed in this application can be prepared by using a standard KrF photolithography process. This high-frequency surface acoustic wave resonance mode has a sound speed (V p = 10.18 km / s) exceeding 10 km / s, and stray mode suppression can be achieved in a large frequency range (5 GHz - 14 GHz), which can meet the application requirements of the surface acoustic wave device in the X-band frequency band.

[0037] The displacement distribution of the higher-order SV-SAW mode, as Figure 3As shown, the Z-direction displacement perpendicular to the propagation direction is mainly concentrated near the piezoelectric single crystal layer. This is attributed to the rigidity and sound velocity difference between the thin film of the piezoelectric single crystal layer and the substrate with a high sound velocity, which can effectively limit the leakage of acoustic energy and form a low-loss acoustic waveguide in the heterogeneous stacked structure of the surface acoustic wave device. The phase velocity of the higher-order SV-SAW exceeds the cutoff sound velocity of the substrate materials sapphire or silicon carbide, so only a small amount of energy leaks along the depth direction of the substrate.

[0038] Thus, through the aforementioned material and structural design, the propagation speed of the surface acoustic wave on the SAW device is significantly increased, enabling the SAW device to meet the application requirements of higher frequencies. The structural parameter design of the SAW device of the present application based on the multi-layer piezoelectric heterogeneous structure enables the SAW device to reach an ultra-high frequency of 10 GHz. Its interdigital electrode line width is relatively large, greater than the limit line width of the standard KrF lithography process in the art. Therefore, the batch preparation of the SAW device can be realized through the standard KrF lithography process, reducing the cost of large-scale production of the SAW device, which has important value for actual production.

[0039] In some embodiments, the acoustic wave propagation direction of the piezoelectric single crystal layer is 0°-15°X. When the acoustic wave propagation direction of the piezoelectric single crystal layer is within the aforementioned range, the intrinsic electromechanical coupling coefficient is relatively large, which is beneficial to achieving efficient acoustic-electric conversion.

[0040] In some embodiments, the thickness of the piezoelectric single crystal layer is 210 nm - 270 nm. By optimizing the orientation and thickness of the piezoelectric single crystal layer materials LN or LT, when the thickness of the piezoelectric single crystal layer is within the aforementioned range, the SAW device of the present application can cover a partial frequency range of the X-band both as a resonator and a filter. Thus, the SAW device of the present application can exhibit an ultra-high center frequency, excellent electromechanical coupling coefficient and quality factor as a resonator, and can exhibit low insertion loss characteristics within the target frequency band as a filter.

[0041] In some embodiments, the line width of the interdigital electrodes of the interdigital transducer is 0.18 μm - 0.30 μm. When the line width of the interdigital electrodes of the interdigital transducer is within the aforementioned range, the wavelength of the SAW device is 0.72 μm - 1.20 μm, which can be used as a super-high frequency resonator and filter with good performance.

[0042] In some embodiments, referring to Figure 1 , it further includes: a functional layer 2, the functional layer 2 is disposed between the substrate 3 and the piezoelectric single crystal layer 1, and the functional layer 2 includes silicon oxide.

[0043] Due to the waveguide effect formed by the low - sound - velocity SiO2 functional layer and the high - sound - velocity substrate, which can suppress the leakage of acoustic wave energy into the substrate, in the multilayer piezoelectric heterostructure of SAW devices, it is possible to effectively excite the ultra - high - frequency SV acoustic wave mode, which can be applied to the preparation of SAW devices responding to the X - band. And the thickness of the SiO2 functional layer can be adjusted to further suppress the spurious modes, adjust the frequency, and improve the response intensity of the target SV mode, etc., thereby further enhancing the performance of the SAW device proposed in this application as a resonator and a filter. In addition, due to the temperature compensation characteristics of SiO2 and the high thermal conductivity of Sapphire, SiC, etc., the SAW device can have high temperature stability and power tolerance. Thus, the functional layer can assist the bonding process or improve the performance of the SAW device. In the multilayer piezoelectric heterostructure of the SAW device, a waveguide effect can be formed among the piezoelectric single - crystal layer, the low - sound - velocity functional layer, and the high - sound - velocity substrate, which can suppress the leakage of low - frequency acoustic wave energy and is beneficial to the excitation of the ultra - high - frequency SV wave mode.

[0044] In some embodiments, the thickness of the functional layer is 60nm - 120nm. By optimizing the LN or LT of the piezoelectric single - crystal layer, the thickness of the functional layer, and the wavelength, within the foregoing range, the functional layer can form a structure with a relatively high response intensity of the target SV mode with the piezoelectric single - crystal layer. Thus, it is beneficial to improve the performance of the SAW device.

[0045] In some embodiments, the interdigital electrodes of the interdigital transducer include at least one of Al, Cu, Pt, and W. Thus, the interdigital electrodes prepared from the foregoing metals are beneficial to increasing the response frequency of the SAW in the SAW device. Among them, Al has a lower density, and a lighter mass load can increase the sound velocity of the corresponding mode, and correspondingly can increase the frequency of the device. Therefore, the Al electrode is suitable for the preparation of high - frequency devices. Cu has a larger density and has a strong mass - loading effect, which is beneficial to suppressing the spurious response around the target mode.

[0046] In some embodiments, the thickness of the interdigital electrodes of the interdigital transducer is 30nm - 150nm. When the thickness of the interdigital electrodes of the interdigital transducer is within the foregoing range, it can reduce the mass - loading effect and reduce the acoustic loss, which is beneficial to the high - frequency application of the SAW device.

[0047] In some embodiments, it further includes: a modification layer, which is disposed between the interdigital transducer and the piezoelectric substrate, and the modification layer includes at least one of Ti, Ni, and Cr. Preparing a modification layer between the interdigital transducer and the piezoelectric substrate can enhance the texture of the interdigital electrode metal film through the metal of the modification layer, such as the (111) texture of the Al metal electrode material, which is beneficial to improving the electromigration resistance of the interdigital electrode.

[0048] In some embodiments, the thickness of the modification layer is 1 nm - 20 nm. When the thickness of the modification layer is within the foregoing range, the modification layer can play a better auxiliary effect on the interdigital electrodes. Thus, it is beneficial to improve the performance of the SAW device.

[0049] In some embodiments, the thickness of the substrate is 30 μm - 1000 μm. When the thickness of the substrate is within the foregoing range, a SAW device with stable performance can be fabricated, and its specific thickness can be adjusted according to application conditions.

[0050] In some embodiments, the line width of the interdigital electrodes of the interdigital transducer is 0.18 μm - 0.30 μm. When the line width of the interdigital transducer is within the foregoing range, it can meet the requirement that the wavelength of the SAW device has the minimum line width and can be mass-produced by using the standard KrF lithography and etching technology.

[0051] The solutions of the present application will be described below through specific embodiments. It should be noted that the following embodiments are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. For those technologies or conditions not specified in the embodiments, they shall be carried out according to the technologies or conditions described in the literature in this field or according to the product specifications. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0052] Example 1

[0053] It mainly includes the following steps:

[0054] (1) Preparation of the silicon oxide thin film as the functional layer: The silicon oxide thin film is grown on a sapphire or silicon carbide substrate by magnetron sputtering coating process.

[0055] (2) Preparation of the multi-layer piezoelectric heterostructure: The above-mentioned double-layer or triple-layer bonded substrate is prepared by using the Smart-cut process.

[0056] (3) Patterned preparation of the surface acoustic wave device: The above-mentioned bonded substrate is patterned by using the standard KrF lithography and etching processes in this industry field, and the overlay process is involved.

[0057] (4) Preparation of the surface acoustic wave device: The top interdigital transducer of metallic aluminum is prepared by using electron beam evaporation method or magnetron sputtering method, and the thickness of the interdigital electrodes is 70 nm, and a 6-inch surface acoustic wave device of 128°Y-XLN / SiO2 / Sapphire multi-layer piezoelectric heterostructure is obtained.

[0058] Example 2

[0059] Example 2 is consistent with Example 1, except that the interdigital transducer of metallic copper is prepared, and the thickness of the interdigital is 80 nm.

[0060] Test method: S-parameter test

[0061] The scattering parameters of SAW devices, also known as S-parameters, can be obtained through a vector network analyzer. Then, by converting the S-parameters into parameters such as admittance, impedance, group delay, and voltage standing wave ratio, the performance of SAW devices can be analyzed. For unencapsulated resonators and filters, on-chip testing is mainly carried out using a microwave probe station and Ground-Signal-Ground (GSG) microwave probes. The tip-to-tip spacing of the probes is 150 μm. An electrical signal is input from the input end of the device through the microwave probe station. After the electrical signal enters the interdigital electrodes, a periodically distributed electric field is formed. Under the action of the electric field, the piezoelectric material generates surface acoustic waves through the inverse piezoelectric effect. The surface acoustic waves propagate to both sides. When they reach the output end, the piezoelectric material generates charges through the direct piezoelectric effect. Thus, an electrical signal can be detected on the interdigital transducer at the output end.

[0062] Test results:

[0063] Reference Figure 4 The admittance response of the resonator shown indicates that the higher-order SV-SAW modes excited by the SAW devices proposed in this application exhibit fewer parasitic modes in a wide frequency range. Whether using Al or Cu as the interdigital electrode material, the center frequency of the SAW device as a resonator decreases with the increase of wavelength, and both show good electromechanical coupling ability (in the range of λ = 0.95 μm - 1.15 μm, K 2 ≈ 10%). Among them, the device with metal Al interdigital electrodes in Example 1 shows a higher frequency response (anti-resonance frequency exceeds 10 GHz) at wavelengths < 1.1 μm, making it an ideal electrode material for the design of ultra-high-frequency filters. The device with metal Cu interdigital electrodes in Example 2 has a higher quality factor and is more advantageous in low-loss filtering applications.

[0064] Figure 5 (a) shows the SAW device with Al electrodes in Example 1 as a resonator, with a wavelength of 0.95 μm and the highest center frequency (f c = 10.52 GHz), and having good electromechanical coupling coefficient (K 2 = 11.10%), admittance ratio (AR = 38 dB), and Bode-Q max (175).

[0065] Figure 5 (b) shows the SAW device with Cu electrodes in Example 2 as a resonator, with a wavelength of 1.10 μm and the highest Bode-Qmax (370), and also having excellent fc (8.20 GHz), K 2(10.80%) and AR (45 dB). It shows that the surface acoustic wave devices proposed in this application have their own advantages in terms of operating frequency, acoustic-electric conversion ability, admittance ratio, quality factor, etc. as resonators, providing feasible optimization solutions for different application scenarios.

[0066] Reference Figure 6 It can be seen that the surface acoustic wave devices proposed in this application can meet the requirements as filters at high operating frequencies. As the S of the high-order SV-SAW filters (A, B, and C) 21 response curve shows a response without parasitic modes within a large frequency range (5 GHz - 11 GHz). Specifically, the surface acoustic wave devices proposed in this application achieve a center frequency of 9.0 GHz - 10.2 GHz as filters, with a minimum insertion loss of 2.96 dB - 3.28 dB and a 3-dB bandwidth (FBW) of approximately 2.4%.

[0067] It should be noted that this application is not limited to the above embodiments. The above embodiments are only examples, and embodiments with the same structure in essence as the technical idea and achieving the same effect within the technical solution scope of this application are all included in the technical scope of this application. In addition, within the scope of not departing from the main idea of this application, various modifications that those skilled in the art can think of to the embodiments, as well as other ways constructed by combining some constituent elements of the embodiments, are also included in the scope of this application.

Claims

1. A surface acoustic wave device, characterized in that: include: A piezoelectric substrate and at least one group of interdigital transducers arranged on the piezoelectric substrate, wherein: The piezoelectric substrate includes a substrate and a piezoelectric single crystal layer. The piezoelectric single crystal layer is arranged on the side of the substrate facing the interdigital transducer. The piezoelectric single crystal layer includes lithium niobate or lithium tantalate. The tangent direction of the piezoelectric single crystal layer is 100°-140°Y. The substrate includes a sapphire substrate or a silicon carbide substrate.

2. The surface acoustic wave device according to claim 1, wherein The acoustic wave propagation direction of the piezoelectric single crystal layer is 0°-15°X.

3. The surface acoustic wave device according to claim 1, wherein The thickness of the piezoelectric single crystal layer is 210nm-270nm.

4. The surface acoustic wave device according to claim 1, wherein The line width of the interdigital electrodes of the IDT is 0.18 μm-0.30 μm.

5. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: Further including: A functional layer is provided between the substrate and the piezoelectric single crystal layer, and the functional layer comprises silicon oxide.

6. The surface acoustic wave device according to claim 5, wherein The thickness of the functional layer is 60nm-120nm.

7. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: The interdigital electrodes of the IDT include at least one of Al, Cu, Pt, and W; and / or, The thickness of the interdigital electrodes of the IDT is 30 nm to 150 nm.

8. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: Further including: A modification layer is provided between the interdigital transducer and the piezoelectric substrate, and the modification layer includes at least one of Ti, Ni, and Cr.

9. The surface acoustic wave device according to claim 8, wherein The thickness of the modified layer is 1 nm to 20 nm.

10. The surface acoustic wave device according to any one of claims 1 to 4, characterized in that: The thickness of the substrate is 30 μm-1000 μm.

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