Elastic wave device, filter or multiplexer

Abstract

The invention discloses an elastic wave device, a filter or a multiplexer, and belongs to the technical field of elastic waves, the elastic wave device comprises a piezoelectric layer, a nitride, a sapphire substrate and a conductive material film pattern; in the third direction, the nitride is arranged on the sapphire substrate, the piezoelectric layer is arranged on the nitride, and the conductive material film pattern is arranged on the piezoelectric layer; the conductive material film pattern comprises interdigital transducer electrodes and reflector electrodes, and the reflector electrodes are located on the two sides of the interdigital transducer electrodes in the first direction. The elastic wave device is good in impedance characteristic and free of any obvious clutter response, can be widely applied to the application fields with high requirements such as communication, radars and wireless sensors, and meets the requirements of a modern communication system for high-frequency and high-performance filters and multiplexers.

Description

Technical Field

[0001] The present invention relates to the field of elastic wave technology, and in particular to an elastic wave device, a filter or a multiplexer. Background Art

[0002] In the existing elastic wave device technology field, the invention patent application CN116601871A discloses an elastic wave device capable of suppressing high-order modes: in the elastic wave device, the substrate is silicon, the composite multilayer structure is four layers, and the substrate structure is relatively complex, which increases the complexity of the structural design of the elastic wave device, the difficulty of the preparation process and the overall cost; at the same time, in the existing elastic wave device technology field, Figure 1 The figure shows an admittance-frequency curve of a surface acoustic wave (SAW) resonator based on a piezoelectric composite substrate. It can be seen from the curve that the main mode of the resonator has a resonant frequency of 1911 MHz, an anti-resonant frequency of 2004 MHz and an electromechanical coupling coefficient of 11.5%, and there is no obvious clutter response except for the main mode; Figure 2 Another surface acoustic wave (SAW) resonator based on a piezoelectric composite substrate has an admittance-frequency curve. From the curve, it can be seen that the main mode of the resonator has a resonant frequency of 1974 MHz, an anti-resonant frequency of 2280 MHz, and an electromechanical coupling coefficient of 33.1%. In addition to the main mode, there are obvious clutter responses near and far from the main mode, and the impedance characteristics are poor. Obviously, the clutter has a corresponding impact on the performance of the elastic wave device, and most of these piezoelectric composite substrate surface acoustic waves (SAW) are based on Si material structures, such as LT / SiO2 / Si structure, LT / SiO2 / Si structure. The presence of Si material will form parasitic conductance at the interface, resulting in large RF loss. Therefore, in the face of these technical problems, it is urgent to improve and optimize the elastic wave device in terms of structural design, material selection and overall preparation to overcome the various limitations of the existing technology so that the elastic wave device can meet higher performance requirements and application needs. Summary of the invention

[0003] The purpose of the present invention is to provide an elastic wave device, filter or multiplexer to partially or completely solve the problems existing in the above-mentioned prior art. To achieve the above-mentioned purpose, the technical solution adopted by the present invention is:

[0004] In the first aspect, the present invention application provides an elastic wave device, comprising: a piezoelectric layer, a nitride, a sapphire substrate and a conductive material thin film pattern; along a third direction, the nitride is arranged on the sapphire substrate, the piezoelectric layer is arranged on the nitride, and the conductive material thin film pattern is arranged on the piezoelectric layer; the conductive material thin film pattern includes an interdigital transducer electrode and a reflector electrode, and along the first direction, the reflector electrode is located on both sides of the interdigital transducer electrode; the nitride is a hexagonal lattice; the plane orientation of the main surface of the sapphire substrate is an r-plane, and the plane orientation of the main surface of the nitride is an a-plane.

[0005] Optionally, the nitride is aluminum nitride or gallium nitride.

[0006] Optionally, the material of the piezoelectric layer is lithium niobate, and the Euler angle is (0°, 90°-150°, 0°).

[0007] In a second aspect, the present invention provides a filter or a multiplexer, including a series arm resonator and a parallel arm resonator, wherein the series arm resonator and the parallel arm resonator include any elastic wave device described in the first aspect.

[0008] The beneficial effects brought about by the technical solution provided by the present invention application include at least:

[0009] (1) In the present invention application, a sapphire substrate is used as a high-sound-velocity substrate for an elastic wave device. After the sapphire substrate is composited with a piezoelectric layer through a nitride, the wavelength of elastic wave propagation is longer, the structural design of the elastic wave device is optimized, and the size and cost of the elastic wave device are appropriately reduced. At the same time, the cost of sapphire materials is gradually controllable, and the processing technology is relatively simple, without the need for complex process steps, so that the preparation of high-performance surface acoustic wave (SAW) devices with simple process and low cost can be achieved. It has obvious advantages in the large-scale production of elastic wave devices, and has greatly promoted the widespread application and commercial development of elastic wave devices in multiple fields such as communications and sensors.

[0010] (2) In the present invention application, the nitride can be aluminum nitride or gallium nitride, the surface orientation of the sapphire substrate is r-plane, and the surface orientation of the aluminum nitride is a-plane. The elastic wave device has the best impedance characteristics and no obvious clutter response. It can not only avoid the loss and parasitic effects caused by traditional Si materials, but also improve the frequency response, signal processing capability and signal transmission stability. The prepared elastic wave device can be widely used in high-demand application fields such as communications, radars, wireless sensors, etc., and meet the needs of modern communication systems for high-frequency, high-performance filters and multiplexers. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0012] Figure 1 is an admittance-frequency curve of a surface acoustic wave (SAW) resonator based on a piezoelectric composite substrate in the prior art;

[0013] Figure 2 is an admittance-frequency curve diagram of another surface acoustic wave (SAW) resonator based on a piezoelectric composite substrate in the prior art;

[0014] Figure 3 is a schematic structural diagram of an elastic wave device 200 of the present invention;

[0015] Figure 4 It is a schematic diagram of the crystal axis, a-plane, m-plane, c-plane and r-plane of the sapphire applied for in the present invention.

[0016] Figure 5 It is a schematic diagram of growing aluminum nitride on a sapphire substrate according to the present invention;

[0017] Figure 6 is a cross-sectional view of an elastic wave device 200 of the present invention application;

[0018] Figure 7 is an admittance-frequency curve diagram of the elastic wave device 200 of the present invention;

[0019] Figure 8 is an admittance-frequency curve diagram of an elastic wave device applied by the present invention;

[0020] Fig. 9 is an admittance-frequency curve diagram of another elastic wave device applied for by the present invention;

[0021] Fig.10 is an admittance-frequency curve diagram of the elastic wave device 200 with different sapphire substrate and aluminum nitride surface orientations of the present invention;

[0022] Fig.11 is a cross-sectional view of an elastic wave device 400 of the present invention;

[0023] Fig.12 It is a graph of admittance-frequency of the elastic wave device 400 of the present invention.

[0024] Fig.13 is an admittance-frequency curve diagram of another elastic wave device applied by the present invention;

[0025] Fig.14 is an admittance-frequency curve diagram of yet another elastic wave device of the present invention; DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Among them, the same parts are represented by the same figure marks. It should be noted that the words "front", "rear", "left", "right", "up" and "down" used in the following description refer to the directions in the drawings of the present application specification, and the words "bottom surface" and "top surface", "inside" and "outside" refer to the direction towards or away from a specific component, respectively. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application specification, the meaning of "multiple" is two or more.

[0028] First, as Figure 3 As shown, an elastic wave device 200 includes: a piezoelectric layer 1, a nitride, a sapphire substrate 5 and a conductive material film pattern; along a third direction, the nitride is arranged on the sapphire substrate 5, the piezoelectric layer 1 is arranged on the nitride, and the conductive material film pattern is arranged on the piezoelectric layer 1; the conductive material film pattern includes an interdigital transducer electrode and a reflector electrode, and along the first direction, the reflector electrodes are located on both sides of the interdigital transducer electrode.

[0029] In some embodiments, the conductive material film pattern includes an IDT electrode 2a, a reflector electrode 2b, a first IDT bus bar 4a, a second IDT bus bar (not shown in the figure, refer to Figure 3 ), the first reflector bus bar 4b and the second reflector bus bar (not shown in the figure, refer to Figure 3 ), the reflector electrode is located on both sides of the IDT electrode, the IDT electrode 2a is connected to the first IDT bus 4a and the second IDT bus, the reflector electrode is connected to the first reflector bus 4b and the second reflector bus, the IDT electrode includes a plurality of transducer electrode fingers, and the reflector electrode includes a plurality of reflection electrode fingers.

[0030] In some embodiments, the first direction is the x-axis direction, and the direction parallel to the x-axis is defined as the arrangement direction of the transducer electrode fingers. The x-axis direction can also be the propagation direction of the elastic wave. The second direction is the y-axis direction, and the direction parallel to the y-axis is defined as the extension direction of the transducer electrode fingers (or reflection electrode fingers). The third direction is the z-axis direction, and the direction parallel to the z-axis is defined as the height direction of the elastic wave device.

[0031] In some implementations, the sapphire substrate 5 can be used as a substrate for the elastic wave device. Compared with the Si substrate in the existing elastic wave device, sapphire has an extremely high resistivity and is an insulator. The high resistivity can avoid current leakage, prevent heat generation and thermal interference caused by leakage, and ensure electrical safety and stability. At the same time, it has a lower dielectric constant, which can reduce electrical losses, improve the efficiency of electrical energy and mechanical energy conversion, and reduce energy waste, making the elastic wave device more accurate and efficient in signal processing and transmission.

[0032] In some embodiments, along the third direction, the nitride is between the sapphire substrate and the piezoelectric layer. The sapphire substrate may have temperature changes in certain working environments or high-power operation. The nitride can effectively disperse heat and play a good thermal buffering role to prevent the performance of the piezoelectric layer from deteriorating due to local overheating, maintain the stability of the piezoelectric characteristics of the piezoelectric layer, and ensure that the elastic wave device works normally within a wider temperature range, thereby improving the thermal reliability and stability of the elastic wave device, reducing the damage to the structure caused by stress caused by thermal expansion and contraction, and extending the service life of the elastic wave device; at the same time, after the acoustic impedance matching between the nitride and the sapphire substrate and the piezoelectric layer is optimized, the reflection and scattering of the elastic wave at the interface can be reduced, making the propagation of the elastic wave in the entire structure smoother and more efficient, reducing the loss of sound wave energy, laying a solid foundation for the stable transmission of the elastic wave, and improving the overall acoustic performance of the elastic wave device.

[0033] Therefore, in the present invention application, a sapphire substrate is used as a high-sound-velocity substrate for an elastic wave device. After the sapphire substrate is compounded with a piezoelectric layer through a nitride, the wavelength of elastic wave propagation is longer, the structural design of the elastic wave device is optimized, and the size and cost of the elastic wave device are appropriately reduced. At the same time, the cost of sapphire materials is gradually controllable, and the processing technology is relatively simple without the need for complex process steps. The preparation of high-performance surface acoustic wave (SAW) devices with simple process and low cost can be achieved, which has obvious advantages in the large-scale production of elastic wave devices and has greatly promoted the widespread application and commercial development of elastic wave devices in communications, sensors and other fields.

[0034] Optionally, the sapphire substrate includes an a-plane, an m-plane, a c-plane and an r-plane. When the plane orientation of the main surface of the sapphire substrate is the a-plane or the c-plane, the plane orientation of the main surface of the nitride is the c-plane; or, when the plane orientation of the main surface of the sapphire substrate is the m-plane, the plane orientation of the main surface of the nitride is the m-plane; when the plane orientation of the main surface of the sapphire substrate is the r-plane, the plane orientation of the main surface of the nitride is the a-plane.

[0035] In some embodiments, Figure 4 As shown, the sapphire substrate includes four crystal planes: a plane, m plane, c plane and r plane. Due to the anisotropy of the crystal material, the sapphire of different crystal planes combined with the piezoelectric layer will have different performances. Sapphire is a single crystal with a hexagonal crystal structure. The crystal axes of sapphire include: α1 axis, α2 axis, α3 axis, C axis, α1 axis, α2 axis, and α3 axis are all perpendicular to the C axis. Due to the symmetry of the crystal structure, the α1 axis, α2 axis, and α3 axis are equivalent. The main surface of the sapphire substrate can be a plane, m plane, c plane, or r plane. .

[0036] In some embodiments, when the main surface of the sapphire substrate is the a-plane, the main surface on the side of the piezoelectric layer 1 in the sapphire substrate becomes the (11-20) plane. The so-called (11-20) plane is a plane orthogonal to the crystal axis represented by the Miller index [11-20] in the crystal structure. In this state, the so-called propagation angle ψ of the elastic wave in the sapphire substrate can be understood as: the angle formed by the elastic wave propagation direction and the crystal orientation

[0001] of the Miller index of the sapphire projected downward along the third direction. On this basis, when the (11-20) plane is represented by the Euler angle, the Euler angle of the (11-20) plane of the sapphire substrate is (90°, 90°, ψ).

[0037] In some embodiments, when the main surface of the sapphire substrate is the c-plane, the main surface of the piezoelectric layer 1 side of the sapphire substrate becomes the (0001) plane. In this state, the so-called propagation angle ψ of the sapphire substrate can be understood as: the angle formed by the elastic wave propagation direction and the crystal orientation

[1000] of the Miller index of the sapphire projected downward along the third direction. On this basis, when the (0001) plane is expressed in Euler angles, the Euler angle of the (0001) plane of the sapphire substrate is (0°, 0°, ψ).

[0038] In some embodiments, when the main surface of the sapphire substrate is an m-plane, the main surface of the piezoelectric layer 1 side of the sapphire substrate becomes a (1-100) plane. In this state, the so-called propagation angle ψ of the sapphire substrate can be understood as: the angle formed by the elastic wave propagation direction and the crystal orientation

[0001] of the Miller index of the sapphire projected downward along the third direction. On this basis, when the (1-100) plane is expressed in Euler angles, the Euler angle of the (1-100) plane of the sapphire substrate is (0°, 90°, ψ).

[0039] In some embodiments, when the main surface of the sapphire substrate is the r-plane, the main surface of the piezoelectric layer 1 side of the sapphire substrate becomes the (1-102) plane. In this state, the so-called propagation angle ψ of the sapphire substrate can be understood as: the angle formed by the elastic wave propagation direction and the crystal orientation [1-10-1] of the Miller index of the sapphire projected downward along the third direction. On this basis, when the (1-102) plane is expressed as the Euler angle, the Euler angle of the (1-102) plane of the sapphire substrate is (0°, 122.23°, ψ).

[0040] In some embodiments, the nitride may have the same lattice structure as the sapphire substrate, that is, a hexagonal lattice structure; or may be different from the sapphire substrate, that is, a non-hexagonal lattice structure.

[0041] In some embodiments, during the material growth process, the crystal orientation of the film is closely related to the crystal structure and orientation of the substrate material. When growing nitride on an a-plane or c-plane sapphire substrate, the main surface of the nitride is usually the c-plane. The c-plane nitride film has an excellent crystal structure, which can provide good acoustic velocity matching and stability. The c-plane nitride film can be suitable for high-frequency and high-power applications; when growing nitride on an m-plane sapphire substrate, the orientation of the main surface of the nitride is generally the m-plane, which can help optimize the surface morphology of the nitride film, reduce interface defects, and improve the electrical and mechanical properties of the film. It can provide excellent conductivity and lower loss, and can be suitable for fields such as radio frequency filters and amplifiers; when growing nitride on an r-plane sapphire substrate, the orientation of the main surface of the nitride is usually the a-plane. The a-plane nitride film can better maintain the stability of the device and prevent performance degradation caused by high temperature or high power, and can be suitable for high-power and high-temperature working devices.

[0042] Therefore, in the present application, by selecting different main surfaces of sapphire substrates (a-plane, c-plane, m-plane or r-plane), the nitride films with different surface orientations can be adjusted in a targeted manner for optimized growth, thereby improving the performance of the elastic wave device, such as reducing electrical losses, improving thermal stability, increasing mechanical strength and optimizing surface acoustic wave transmission, etc., to meet the application requirements of the elastic wave device in different scenarios.

[0043] Optionally, the nitride is a hexagonal lattice, the plane orientation of the main surface of the sapphire substrate is r-plane, the plane orientation of the main surface of the nitride is a-plane, the nitride is aluminum nitride, the material of the piezoelectric layer 1 is lithium niobate, and the Euler angle is (0°, 90°-150°, 0°).

[0044] In some embodiments, Figure 6As shown, the nitride included in the elastic wave device 200 is aluminum nitride 6, the plane orientation of the main surface of the sapphire substrate 5 is r-plane, and the thickness of the sapphire substrate 5 along the third direction is 500μm; the plane orientation of the main surface of the aluminum nitride 6 is a-plane, and the thickness of the aluminum nitride 6 along the third direction is 100nm; the material of the piezoelectric layer 1 is lithium niobate, and the piezoelectric layer 1 is 32°Y-cut lithium niobate with an Euler angle of (0°, 122°, 0°), and the thickness of the piezoelectric layer 1 along the third direction is 500nm; the wavelength λ of the elastic wave is 2μm; the material of the conductive material thin film pattern is aluminum, and the thickness of the conductive material thin film pattern along the third direction is 160nm.

[0045] In some embodiments, Figure 7 As shown in the graph, it can be seen that the main mold of the elastic wave device 200 has a resonant frequency of 2074 MHz and an anti-resonant frequency of 2312 MHz, and an electromechanical coupling coefficient of 25.4%. In addition, the elastic wave device 200 has no obvious clutter response and has excellent impedance characteristics.

[0046] In some embodiments, based on the elastic thin device 200, the Euler angle (0°, 122°, 0°) of the piezoelectric layer 1 can be adjusted to the Euler angle (0°, 90°, 0°), and other parameters remain unchanged. That is, similarly, the nitride included in the elastic wave device is aluminum nitride 6, the surface orientation of the main surface of the sapphire substrate 5 is r-plane, and the thickness of the sapphire substrate 5 along the third direction is 500μm; the surface orientation of the main surface of the aluminum nitride 6 is a-plane, and the thickness of the aluminum nitride 6 along the third direction is 100nm; the material of the piezoelectric layer 1 is lithium niobate, the piezoelectric layer 1 is 32°Y-cut lithium niobate, the Euler angle is (0°, 90°, 0°), and the thickness of the piezoelectric layer 1 along the third direction is 500nm; the wavelength λ of the elastic wave is 2μm; the material of the conductive material thin film pattern is aluminum, and the thickness of the conductive material thin film pattern along the third direction is 160nm.

[0047] In some embodiments, Figure 8 As shown in the graph, it can be seen that the main mold of the elastic wave device has a resonant frequency of 2098 MHz and an anti-resonant frequency of 2378 MHz, and the electromechanical coupling coefficient is 29.1%. In addition, the elastic wave device 200 has an acceptable small clutter response within the band, no obvious clutter response outside the band, and has excellent impedance characteristics.

[0048] In some embodiments, based on the elastic thin device 200, the Euler angle (0°, 122°, 0°) of the piezoelectric layer 1 can also be adjusted to the Euler angle (0°, 150°, 0°), and other parameters remain unchanged. That is, similarly, the nitride included in the elastic wave device is aluminum nitride 6, the surface orientation of the main surface of the sapphire substrate 5 is r-plane, and the thickness of the sapphire substrate 5 along the third direction is 500μm; the surface orientation of the main surface of the aluminum nitride 6 is a-plane, and the thickness of the aluminum nitride 6 along the third direction is 100nm; the material of the piezoelectric layer 1 is lithium niobate, and the piezoelectric layer 1 is 32°Y-cut lithium niobate, the Euler angle is (0°, 150°, 0°), and the thickness of the piezoelectric layer 1 along the third direction is 500nm; the wavelength λ of the elastic wave is 2μm; the material of the conductive material thin film pattern is aluminum, and the thickness of the conductive material thin film pattern along the third direction is 160nm.

[0049] In some embodiments, Fig. 9 As shown in the graph, it can be seen that the main mold of the elastic wave device has a resonant frequency of 2264 MHz and an anti-resonant frequency of 2406 MHz, and the electromechanical coupling coefficient is 14.6%. In addition, the elastic wave device 200 has no obvious clutter response and has excellent impedance characteristics.

[0050] In some embodiments, Fig.10 As shown, it can be seen from the curve graph that when the surface orientation of the sapphire substrate is the c-plane and the surface orientation of the aluminum nitride is the a-plane, or when the surface orientation of the sapphire substrate is the c-plane and the surface orientation of the aluminum nitride is the c-plane, or when the surface orientation of the sapphire substrate is the m-plane and the surface orientation of the aluminum nitride is the m-plane, the impedance characteristics of the elastic wave device 200 are general, and have certain noise responses near the resonator frequency or far away from the resonant frequency; however, when the surface orientation of the sapphire substrate is the r-plane and the surface orientation of the aluminum nitride is the a-plane, the impedance characteristics of the elastic wave device 200 are better, that is, when the surface orientation of the sapphire substrate is the r-plane and the surface orientation of the aluminum nitride is the a-plane, the impedance characteristics of the elastic wave device 200 are the best, without any obvious noise responses.

[0051] Optionally, the plane orientation of the main surface of the sapphire substrate is r-plane, the plane orientation of the main surface of the nitride is a-plane, the nitride is gallium nitride, the material of the piezoelectric layer 1 is lithium niobate, and the Euler angle is (0°, 90°-150°, 0°).

[0052] In some embodiments, Fig.11As shown, the nitride included in the elastic wave device 400 is gallium nitride 8, the plane orientation of the main surface of the sapphire substrate 5 is r-plane, and the thickness of the sapphire substrate 5 along the third direction is 500μm; the plane orientation of the main surface of the hexagonal lattice gallium nitride 8 is a-plane, and the thickness of the gallium nitride 8 along the third direction is 100nm; the material of the piezoelectric layer 1 is lithium niobate, and the piezoelectric layer 1 is 32°Y-cut lithium niobate with Euler angles of (0°, 122°, 0°), and the thickness of the piezoelectric layer 1 along the third direction is 500nm; the wavelength λ of the elastic wave is 2μm; the material of the conductive material thin film pattern is aluminum, and the thickness of the conductive material thin film pattern along the third direction is 160nm.

[0053] In some embodiments, Fig.12 As shown in the graph, it can be seen that the main mold of the elastic wave device 400 has a resonant frequency of 2044 MHz and an anti-resonant frequency of 2278 MHz, and an electromechanical coupling coefficient of 25.3%. In addition, the elastic wave device 400 has no obvious clutter response and has excellent impedance characteristics.

[0054] In some embodiments, based on the elastic thin device 400, the Euler angle (0°, 122°, 0°) of the piezoelectric layer 1 can also be adjusted to the Euler angle (0°, 90°, 0°), and other parameters remain unchanged, that is, similarly, the nitride included in the elastic wave device is gallium nitride 8, the surface orientation of the main surface of the sapphire substrate 5 is r-plane, and the thickness of the sapphire substrate 5 along the third direction is 500μm; the surface orientation of the main surface of the hexagonal lattice gallium nitride 8 is a-plane, and the thickness of the gallium nitride 8 along the third direction is 100nm; the material of the piezoelectric layer 1 is lithium niobate, the piezoelectric layer 1 is 32°Y-cut lithium niobate, the Euler angle is (0°, 90°, 0°), and the thickness of the piezoelectric layer 1 along the third direction is 500nm; the wavelength λ of the elastic wave is 2μm; the material of the conductive material thin film pattern is aluminum, and the thickness of the conductive material thin film pattern along the third direction is 160nm.

[0055] In some embodiments, Fig.13 As shown in the graph, it can be seen that the main mold of the elastic wave device has a resonant frequency of 2000 MHz and an anti-resonant frequency of 2280 MHz, and the electromechanical coupling coefficient is 30.3%. In addition, the elastic wave device 400 has an acceptable small clutter response within the band, no obvious clutter response outside the band, and has excellent impedance characteristics.

[0056] In some embodiments, based on the elastic thin device 400, the Euler angle (0°, 122°, 0°) of the piezoelectric layer 1 can also be adjusted to the Euler angle (0°, 150°, 0°), and other parameters remain unchanged, that is, similarly, the nitride included in the elastic wave device is gallium nitride 8, the surface orientation of the main surface of the sapphire substrate 5 is r-plane, and the thickness of the sapphire substrate 5 along the third direction is 500μm; the surface orientation of the main surface of the hexagonal lattice gallium nitride 8 is a-plane, and the thickness of the gallium nitride 8 along the third direction is 100nm; the material of the piezoelectric layer 1 is lithium niobate, and the piezoelectric layer 1 is 32°Y-cut lithium niobate, the Euler angle is (0°, 150°, 0°), and the thickness of the piezoelectric layer 1 along the third direction is 500nm; the wavelength λ of the elastic wave is 2μm; the material of the conductive material thin film pattern is aluminum, and the thickness of the conductive material thin film pattern along the third direction is 160nm.

[0057] In some embodiments, Fig.14 As shown in the graph, it can be seen that the main mold of the elastic wave device has a resonant frequency of 2044 MHz and an anti-resonant frequency of 2278 MHz, and the electromechanical coupling coefficient is 15.7%. In addition, the elastic wave device 400 has no obvious clutter response and has excellent impedance characteristics.

[0058] In a second aspect, the present invention provides a filter or a multiplexer, including a series arm resonator and a parallel arm resonator, wherein the series arm resonator and the parallel arm resonator include any elastic wave device described in the first aspect.

[0059] It should be noted that a filter or multiplexer applied for in the present invention includes any elastic wave device in the first aspect, and accordingly also includes all the recorded technical problems, technical solutions and technical effects of any elastic wave device in the first aspect, which will not be repeated in the present invention application.

[0060] In the present invention application, the filter or multiplexer provided by the present invention application includes a series arm resonator and a parallel arm resonator, and adopts any elastic wave device in the first aspect. First, benefiting from the excellent impedance characteristics and noise-free response of the elastic wave device, signal distortion and interference are reduced, and the signal transmission capability is enhanced. Especially in the application of the multiplexer, the elastic wave device can be used to achieve independent selection and processing of multiple frequency bands, effectively improving the spectrum utilization and parallel processing capability of multiple frequency bands; in addition, the combined design of the series arm resonator and the parallel arm resonator can make the filter or multiplexer present more precise control in frequency response, provide a more refined filtering effect, and the series arm resonator can enhance the band width of the filter or multiplexer. The parallel arm resonator helps to improve the band-stop characteristics of the filter or multiplexer. The combination of the two can better suppress unnecessary frequency signals and ensure effective transmission of the target frequency band. In addition, by using the elastic wave device of the first aspect, the frequency response, signal processing capability and signal transmission stability can be improved, which can not only avoid the loss and parasitic effects caused by traditional Si materials, but also reduce the size and cost of the elastic wave device by optimizing the structural design of the elastic wave device, and further improve the stability and reliability of the filter or multiplexer. The prepared elastic wave device can be widely used in high-demand application fields such as communications, radars, wireless sensors, etc., and meet the needs of modern communication systems for high-frequency, high-performance filters and multiplexers.

[0061] In the embodiments disclosed in the present application, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments disclosed in the present application can be understood according to specific circumstances.

[0062] The above is only a preferred implementation of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An elastic wave device, characterized in that: include: Piezoelectric layer, nitride, sapphire substrate and conductive material film patterning; Along the third direction, the nitride is arranged on the sapphire substrate, the piezoelectric layer is arranged on the nitride, and the conductive material film pattern is arranged on the piezoelectric layer; the conductive material film pattern includes an interdigital transducer electrode and a reflector electrode, and along the first direction, the reflector electrode is located on both sides of the interdigital transducer electrode; the nitride is a hexagonal lattice; the plane orientation of the main surface of the sapphire substrate is the r plane, and the plane orientation of the main surface of the nitride is the a plane.

2. The elastic wave device according to claim 1, wherein: The nitride is aluminum nitride or gallium nitride.

3. The elastic wave device according to claim 2, wherein: The material of the piezoelectric layer is lithium niobate, and the Euler angle is (0°, 90°-150°, 0°).

4. A filter or multiplexer comprising a series arm resonator and a parallel arm resonator, characterized in that: The series arm resonator and the parallel arm resonator include the elastic wave device according to any one of claims 1 to 3.

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