A pseudo-mode suppression high-frequency acoustic resonator

Abstract

The present invention provides a pseudo-mode suppression type high-frequency acoustic wave resonator, which includes: a substrate, a piezoelectric layer, and interdigital electrodes; the interdigital electrodes include a first bus bar and a second bus bar arranged relative to each other in a first direction, and a plurality of electrode fingers located between the first bus bar and the second bus bar. The electrode fingers are arranged in such a manner that a plurality of first-level gap points and a plurality of second-level gap points are sequentially connected to form a two-dimensional virtual polygon, and any two sides of the virtual polygon are not parallel to each other, thereby changing the spatial electric field distribution, adjusting the high-order acoustic waves excited in the length direction and the propagation direction, and thus weakening the vibration amplitude of the pseudo-mode, effectively suppressing the pseudo-mode, and avoiding the need for additional processes and other factors affecting performance. The resulting high-frequency acoustic wave resonator can not only effectively suppress the pseudo-mode but also improve the in-band flatness of the filter, thereby avoiding affecting the performance of the acoustic wave resonator.

Description

Technical Field

[0001] The present invention relates to the field of high-frequency acoustic wave resonators, and more particularly to a pseudo-mode suppression type high-frequency acoustic wave resonator. Background Art

[0002] In future wireless communication systems, RF front-end technology is regarded as a key technology. As the core component of the RF front-end, the performance of the RF filter will have a direct impact on the transceiver system. Therefore, research on high-frequency and high-performance RF filters is the main direction of future development.

[0003] As a type of radio frequency filter, the acoustic wave resonator of the acoustic wave filter can use the e of common piezoelectric film materials. 13 The piezoelectric coefficient effectively excites the S1 vibration mode with high quality factor and high working efficiency on the piezoelectric film of the same thickness; however, there are complex parasitic resonance pseudo-modes near the resonance point of the S1 vibration mode. This pseudo-mode will cause a large amount of ripples in the passband of the acoustic wave filter, thereby increasing the insertion loss and delay time, and deteriorating the performance of the acoustic wave filter. Therefore, achieving pseudo-mode suppression in the high frequency band is one of the keys to achieving high-performance filtering.

[0004] Currently, the main methods for suppressing pseudo-modes in acoustic wave resonators are to optimize the aperture length or adjust the wavelength length. However, this method will leak acoustic wave energy and increase losses, which will greatly affect the filtering performance of acoustic wave filters and greatly limit the application and development of acoustic wave resonators. Therefore, it is a technical problem that technicians in this field urgently need to solve to develop high-frequency acoustic wave resonators that can effectively suppress pseudo-modes without reducing working performance. Summary of the Invention

[0005] In view of this, in order to solve the above problems, the present invention provides a pseudo-mode suppression type high-frequency acoustic wave filter, the technical solution is as follows:

[0006] A pseudo-mode suppression type high-frequency acoustic wave resonator, comprising:

[0007] substrate;

[0008] a piezoelectric layer located on one side of the substrate;

[0009] a plurality of interdigital electrodes located on a side of the piezoelectric layer facing away from the substrate;

[0010] The interdigitated electrode includes a first bus bar and a second bus bar arranged opposite to each other in a first direction, and a plurality of electrode fingers located between the first bus bar and the second bus bar, the electrode fingers including a first electrode and a second electrode;

[0011] In the second direction, the first electrode includes a plurality of first electrode fingers and a plurality of first dummy electrode fingers alternately arranged on a side of the first bus bar facing the second bus bar, and the second electrode includes a plurality of second electrode fingers and a plurality of second dummy electrode fingers alternately arranged on a side of the second bus bar facing the first bus bar, the first direction and the second direction are both parallel to the plane of the substrate, and the second direction is perpendicular to the first direction;

[0012] The first electrode finger and the second dummy electrode finger are arranged opposite to each other in the first direction, the first dummy electrode finger and the second electrode finger are arranged opposite to each other in the first direction, a first-level gap point exists between the first electrode finger and the second dummy electrode finger, and a second-level gap point exists between the first dummy electrode finger and the second electrode finger;

[0013] Wherein, a plurality of the first-level gap points and a plurality of the second-level gap points are sequentially connected as vertices to form a virtual polygon, and any two sides of the virtual polygon are not parallel to each other.

[0014] Preferably, in the above-mentioned pseudo-mode suppression type high-frequency acoustic wave resonator, the virtual polygon is a five-vertex polygon, and the internal angles of the five-vertex polygon are all less than 180°.

[0015] Preferably, in the above-mentioned pseudo-mode suppression type high-frequency acoustic wave resonator, the high-frequency acoustic wave resonator further comprises:

[0016] a release layer between the substrate and the piezoelectric layer;

[0017] a plurality of through holes extending through the piezoelectric layer;

[0018] An air cavity is located between the substrate and the piezoelectric layer, and the air cavity is communicated with the through hole.

[0019] Preferably, in the above-mentioned pseudo-mode suppression type high-frequency acoustic wave resonator, the high-frequency acoustic wave resonator further comprises: a temperature compensation layer;

[0020] The temperature compensation layer is located on a side of the piezoelectric layer facing away from the substrate;

[0021] And / or the temperature compensation layer is located on a side of the piezoelectric layer facing the substrate.

[0022] Preferably, in the above-mentioned pseudo-mode suppression type high-frequency acoustic wave resonator, the direction of the electric field formed by the interdigital electrodes is at an Euler angle θ with respect to the +Y-axis direction of the piezoelectric layer in the global coordinate system, and the value range of the Euler angle θ is -40° to +40°;

[0023] The interdigital electrodes are arranged on a side of the piezoelectric layer facing away from the substrate based on the Euler angle θ.

[0024] Preferably, in the above-mentioned pseudo-mode suppression type high-frequency acoustic wave resonator, the first bus bar has a semicircular structure, and the second bus bar has a semicircular structure.

[0025] Preferably, in the above-mentioned pseudo-mode suppression type high-frequency acoustic wave resonator, the width of the first bus bar in the first direction is 0.01-10 times the wavelength of the interdigital electrode;

[0026] The width of the second bus bar in the first direction is 0.01-10 times the wavelength of the interdigital electrodes.

[0027] Preferably, in the above-mentioned pseudo-mode suppression type high-frequency acoustic wave resonator, the length of the first pseudo electrode finger in the first direction is 0.5-10 times the wavelength of the interdigital electrode, and the length of the second pseudo electrode finger in the first direction is 0.5-10 times the wavelength of the interdigital electrode;

[0028] The length of the first electrode finger in the first direction is 8-40 times the wavelength of the interdigital electrode, and / or the length of the second electrode finger in the first direction is 8-40 times the wavelength of the interdigital electrode;

[0029] In the first direction, the length of the first dummy electrode finger is smaller than the length of the first electrode finger, and the length of the second dummy electrode finger is smaller than the length of the second electrode finger.

[0030] Preferably, in the above-mentioned pseudo-mode suppression type high-frequency acoustic wave resonator, the spacing between the first electrode finger and the second pseudo-electrode finger is 0.2-5 times the wavelength of the interdigital electrode;

[0031] The distance between the first dummy electrode fingers and the second electrode fingers is 0.2-5 times the wavelength of the interdigital electrodes.

[0032] Preferably, in the above-mentioned pseudo-mode suppression type high-frequency acoustic wave resonator, the thickness of the piezoelectric layer ranges from 10 nm to 5000 nm;

[0033] The thickness of the interdigital electrodes ranges from 10 nm to 5000 nm;

[0034] The number of the interdigital electrodes ranges from 2 to 400;

[0035] The distance between two adjacent interdigital electrodes ranges from 0.1 μm to 30 μm.

[0036] The width of each of the interdigital electrodes in the second direction ranges from 0.1 um to 15 um.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The present invention provides a pseudo-mode suppression type high-frequency acoustic wave resonator, which includes: a substrate; a piezoelectric layer located on one side of the substrate; a plurality of interdigitated electrodes located on a side of the piezoelectric layer facing away from the substrate; the interdigitated electrodes include a first bus bar and a second bus bar arranged opposite to each other in a first direction, and a plurality of electrode fingers located between the first bus bar and the second bus bar, the electrode fingers including a first electrode and a second electrode; in a second direction, the first electrode includes a plurality of first electrode fingers and a plurality of first pseudo-electrode fingers alternately arranged on a side of the first bus bar facing the second bus bar, and the second electrode includes a plurality of first electrode fingers and a plurality of first pseudo-electrode fingers alternately arranged on a side of the second bus bar facing the first bus bar. Multiple second electrode fingers and multiple second dummy electrode fingers are alternately arranged on the sides, wherein the first direction and the second direction are both parallel to the plane of the substrate, and the second direction is perpendicular to the first direction; the first electrode fingers and the second dummy electrode fingers are arranged relative to each other in the first direction, the first dummy electrode fingers and the second electrode fingers are arranged relative to each other in the first direction, a first-level gap point is defined between the first electrode fingers and the second dummy electrode fingers, and a second-level gap point is defined between the first dummy electrode fingers and the second electrode fingers; wherein the multiple first-level gap points and the multiple second-level gap points are sequentially connected as vertices to form a virtual polygon, and no two sides of the virtual polygon are parallel to each other. The virtual polygon arrangement formed by the present invention is a two-dimensional arrangement, and no two sides of the virtual polygon formed are parallel to each other, thereby changing the spatial electric field distribution, adjusting the high-order acoustic waves excited in the length direction and propagation direction, and thereby weakening the vibration amplitude of the pseudo-mode, effectively suppressing the pseudo-mode, and avoiding the need for additional processes and other factors that affect performance. The resulting high-frequency acoustic wave resonator can not only effectively suppress the pseudo-mode but also improve the in-band flatness of the filter, avoiding affecting the performance of the resonator. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0040] Figure 1 A schematic structural diagram of a pseudo-mode suppression type high-frequency acoustic wave resonator provided in an embodiment of the present invention;

[0041] Figure 2 A schematic diagram of a top view of an interdigital electrode provided in an embodiment of the present invention;

[0042] Figure 3 A schematic diagram of a vibration mode of an acoustic wave resonator S1 provided in an embodiment of the present invention;

[0043] Figure 4 A test performance diagram of a high-frequency acoustic wave resonator provided by an embodiment of the present invention that does not adopt a two-dimensional apodization method;

[0044] Figure 5 A test performance diagram of a high-frequency acoustic wave resonator using a two-dimensional apodization method provided by an embodiment of the present invention;

[0045] Figure 6 A schematic structural diagram of another pseudo-mode suppression type high-frequency acoustic wave resonator provided by an embodiment of the present invention;

[0046] Figure 7 A schematic structural diagram of another pseudo-mode suppression type high-frequency acoustic wave resonator provided in an embodiment of the present invention;

[0047] Figure 8 A schematic structural diagram of another pseudo-mode suppression type high-frequency acoustic wave resonator provided in an embodiment of the present invention;

[0048] Figure 9 A schematic top view of another interdigitated electrode structure provided by an embodiment of the present invention;

[0049] Figure 10 A schematic top view of another interdigital electrode structure provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0051] Based on the problem that the acoustic wave resonator in the prior art still affects the filtering performance of the acoustic wave filter while suppressing pseudo modes, an embodiment of the present invention provides a pseudo-mode suppression type high-frequency acoustic wave resonator, which can effectively suppress pseudo modes in the high frequency band and avoid affecting the performance of the acoustic wave resonator.

[0052] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] refer to Figure 1 , Figure 1A schematic structural diagram of a pseudo-mode suppression high-frequency acoustic wave resonator provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the high-frequency acoustic wave resonator includes: a substrate 1; a piezoelectric layer 2 located on one side of the substrate 1; and a plurality of interdigital electrodes 3 located on a side of the piezoelectric layer 2 away from the substrate 1.

[0054] Specifically, in the embodiment of the present invention, the interdigital electrodes 3 are deposited on the side of the piezoelectric layer 2 facing away from the substrate 1 by methods including but not limited to electron beam evaporation, plasma, thermal evaporation, magnetron sputtering, etc.

[0055] refer to Figure 2 , Figure 2 A schematic diagram of a top view of an interdigital electrode 3 provided in an embodiment of the present invention is shown in FIG. Figure 2 As shown, the interdigitated electrode 3 includes a first bus bar 4 and a second bus bar 5 arranged opposite to each other in a first direction A, and a plurality of electrode fingers located between the first bus bar 4 and the second bus bar 5, and the electrode fingers include a first electrode and a second electrode; in a second direction B, the first electrode includes a plurality of first electrode fingers 6 and a plurality of first pseudo-electrode fingers 7 alternately arranged on the side of the first bus bar 4 facing the second bus bar 5, and the second electrode includes a plurality of second electrode fingers 8 and a plurality of second pseudo-electrode fingers 9 alternately arranged on the side of the second bus bar 5 facing the first bus bar 4, the first direction A and the second direction B are both parallel to the plane where the substrate 1 is located, and the second direction B is perpendicular to the first direction A.

[0056] Specifically, in the embodiment of the present invention, combined with Figure 2 The first direction A is the direction from the first bus bar 4 to the second bus bar 5 as the positive direction, the first electrode is connected to the first bus bar 4 and extends toward the second bus bar 5 along the positive direction of the first direction A, the second electrode is connected to the second bus bar 5 and extends toward the first bus bar 4 along the reverse direction of the first direction A; the arrangement of the first electrodes is Figure 2 In the example, the first electrode finger 6, the first dummy electrode finger 7, the first electrode finger 6 and the first dummy electrode finger 7 are sequentially arranged along the second direction B; the arrangement of the second electrodes is as follows: Figure 2 In this example, along the second direction B, the second electrode fingers 8 , the second dummy electrode fingers 9 , the second electrode fingers 8 , and the second dummy electrode fingers 9 are sequentially arranged.

[0057] The first electrode finger 6 and the second pseudo electrode finger 9 are arranged relative to each other in the first direction A, the first pseudo electrode finger 7 and the second electrode finger 8 are arranged relative to each other in the first direction A, there is a first-level gap point 10 between the first electrode finger 6 and the second pseudo electrode finger 9, and there is a second-level gap point 11 between the first pseudo electrode finger 7 and the second electrode finger 8; wherein, multiple first-level gap points 10 and multiple second-level gap points 11 are connected in sequence as vertices to form a virtual polygon, and any two sides of the virtual polygon are not parallel to each other.

[0058] Specifically, in an embodiment of the present invention, the first-level gap point 10 is located at the midpoint of the gap between the first electrode finger 6 and the second pseudo electrode finger 9 , and the second-level gap point 11 is located at the midpoint of the gap between the first pseudo electrode finger 7 and the second electrode finger 8 .

[0059] From the above description, it can be seen that the virtual polygon arrangement formed by the present invention is a two-dimensional arrangement. Any two sides of the virtual polygon formed are not parallel to each other, thereby changing the spatial electric field distribution, adjusting the high-order sound waves excited in the length direction and propagation direction, and then weakening the vibration amplitude of the pseudo-mode, effectively suppressing the pseudo-mode, and without the need to add additional processes, avoiding other factors affecting performance. The obtained high-frequency acoustic wave resonator can not only effectively suppress the pseudo-mode but also improve the in-band flatness of the filter, avoiding affecting the performance of the resonator.

[0060] Optionally, in another embodiment provided by the present invention, for the plurality of first-level gap points 10 and the plurality of second-level gap points 11 as vertices sequentially connected to form a virtual polygon, an optional implementation method is provided, referring to Figure 2 , the virtual polygon is a five-vertex polygon, and the internal angles of the five-vertex polygon are all less than 180°.

[0061] Specifically, in the embodiment of the present invention, Figure 2 The example of the interdigitated electrode 3 having five groups of adjacent electrode finger pairs is described, the first-level gap point 10 includes a first-level first gap point 101 and a first-level second gap point 102, the second-level gap point 11 includes a second-level first gap point 111, a second-level second gap point 112 and a second-level third gap point 113, the first-level gap points 10 are connected in sequence along the second direction B, the second-level gap points 11 are connected in sequence along the second direction B, the first-level first gap point 101 and the second-level first gap point 111 are connected, the last gap point of the first-level gap point 10 and the last gap point of the second-level gap point 11 are connected, that is, Figure 2The first-level second gap point 102 is connected to the second-level third gap point 113, and the pattern formed by connecting the gap points in the above manner is a pentagon, and the internal angles of the pentagon are all less than 180°; it should be noted that the electrode finger pairs in the interdigitated electrode 3 are not limited to five groups of electrode finger pairs, and the number of electrode finger pairs set can be determined according to the performance of the acoustic wave resonator.

[0062] Since the distribution of the interdigital electrodes 3 is one of the important factors affecting the electric field distribution characteristics, different apodization methods should be used to adapt to different acoustic wave vibration modes, such as Figure 3 As shown, Figure 3 A schematic diagram of the S1 vibration mode of an acoustic wave resonator provided in an embodiment of the present invention, taking the Euler angle of 0 degrees as an example, for the S1 vibration mode, its propagation direction is the X-axis direction in the global coordinate system, and its vibration direction is the Z-axis direction in the global coordinate system. During the excitation of the acoustic wave, the Y-axis and X-axis directions generate high-order acoustic wave vibrations of other vibration modes, thereby generating coupling in the propagation direction, making it difficult to decouple the vibration of the high-order mode and the S1 mode of the main vibration, resulting in longitudinal and transverse pseudo-modes; and using the two-dimensional trace method provided in an embodiment of the present invention, any two sides of the virtual polygon formed are not parallel to each other, so that high-order acoustic waves in the same direction will not be superimposed, thereby weakening the vibration amplitude of the pseudo-mode, and can effectively suppress the longitudinal and transverse pseudo-modes of the S1 vibration mode, reference Figure 4 and Figure 5 , Figure 4 This is a test performance diagram of a high-frequency acoustic wave resonator provided by an embodiment of the present invention that does not adopt a two-dimensional apodization method. Figure 5 This is a test performance diagram of a high-frequency acoustic wave resonator using a two-dimensional apodization method provided by an embodiment of the present invention. Figure 4 and Figure 5 The vertical axis represents the pseudo-modal vibration amplitude, and the horizontal axis represents the resonant frequency. By comparison Figure 4 and Figure 5 It can be concluded that after adopting the two-dimensional tracking method, the pseudo-modal vibration amplitude near the resonant frequency is suppressed while ensuring that the resonant frequency remains basically unchanged, which can better meet the performance requirements of acoustic wave filters in current high-frequency bands such as 5G and 6G.

[0063] Optionally, in another embodiment of the present invention, referring to Figure 3 The direction of the electric field formed by the interdigitated electrode 3 is at an Euler angle θ with respect to the +Y-axis direction of the piezoelectric layer 2 in the global coordinate system, and the value range of the Euler angle θ is -40° to +40°; the interdigitated electrode 3 is arranged on the side of the piezoelectric layer 2 away from the substrate 1 based on the Euler angle θ.

[0064] Specifically, in the embodiment of the present invention, the direction of the electric field formed by the interdigitated electrodes 3 is Figure 3 The electric field direction is parallel to the XY plane in the global coordinate system, and the positive direction of the Y axis of the piezoelectric layer 2 in the global coordinate system constitutes an Euler angle θ. The Euler angle θ can take any value in the range of -40° to +40°. For example, the Euler angle θ can be -40°, 0°, +40°, etc.; the Euler angle θ taking a value in the range of -40° to +40° can make the acoustic wave resonator in the S1 mode, and by changing the Euler angle θ, the acoustic wave can vibrate significantly in the S1 vibration mode.

[0065] Optionally, in another embodiment of the present invention, combined with Figure 1 , the structure of the above-mentioned pseudo-mode suppression type high-frequency acoustic wave resonator is further described. The high-frequency acoustic wave resonator also includes a release layer 12 located between the substrate 1 and the piezoelectric layer 2; a plurality of through holes 13 passing through the piezoelectric layer 2; and an air cavity 14 located between the substrate 1 and the piezoelectric layer 2, the air cavity 14 being connected to the through holes 13.

[0066] Specifically, in an embodiment of the present invention, the release layer 12 can be a single release layer 12 or multiple release layers 12; after the release layer 12 and the piezoelectric layer 2 are sequentially formed on one side of the substrate 1, a plurality of through holes 13 are formed through the piezoelectric layer 2, and an air cavity 14 is formed between the substrate 1 and the piezoelectric layer 2 based on the through holes 13; the acoustic impedance between the air cavity 14 and the piezoelectric layer 2 is mismatched, so that the piezoelectric layer 2 maintains vibration in the Z-axis direction in the global coordinate system.

[0067] a temperature compensation layer 15 ; the temperature compensation layer 15 is located on a side of the piezoelectric layer 2 facing away from the substrate 1 ; and / or the temperature compensation layer 15 is located on a side of the piezoelectric layer 2 facing the substrate 1 .

[0068] Specifically, in the embodiment of the present invention, the temperature compensation layer 15 can compensate for the temperature coefficient of the piezoelectric layer 2 to ensure that the high-frequency acoustic wave resonator operates normally and stably within a certain temperature variation range.

[0069] The embodiment of the present invention provides several configuration methods of the temperature compensation layer 15, which are detailed as follows: The first method is as follows: Figure 6 As shown, Figure 6 A schematic structural diagram of another pseudo-mode suppression type high-frequency acoustic wave resonator provided in an embodiment of the present invention, Figure 6 The temperature compensation layer 15 is located on the side of the piezoelectric layer 2 away from the substrate 1, and the temperature compensation layer 15 covers the interdigitated electrodes 3; the second type, as Figure 7 As shown, Figure 7A schematic structural diagram of another pseudo-mode suppression type high-frequency acoustic wave resonator provided in an embodiment of the present invention, wherein, on the basis of having an air cavity 14, the temperature compensation layer 15 is formed on the side of the piezoelectric layer 2 facing the substrate 1, and the temperature compensation layer 15 does not cover the interdigital electrode 3; a third type, such as Figure 8 As shown, Figure 8 A structural schematic diagram of another pseudo-mode suppressed high-frequency acoustic wave resonator provided in an embodiment of the present invention, on the basis of having an air cavity 14, the temperature compensation layer 15 is formed simultaneously on the side of the piezoelectric layer 2 away from the substrate 1 and on the side of the piezoelectric layer 2 facing the substrate 1, the temperature compensation layer 15 on the side of the piezoelectric layer 2 away from the substrate 1 covers the interdigitated electrodes 3, and the temperature compensation layer 15 formed on the side of the piezoelectric layer 2 facing the substrate 1 does not cover the interdigitated electrodes 3.

[0070] It should be noted that, in the embodiment of the present invention, the above Figure 6-Figure 8 The temperature compensation layer 15 shown is formed on the basis that the interdigitated electrodes 3 are located on the side of the piezoelectric layer 2 facing away from the substrate 1; the interdigitated electrodes 3 can also be located on the side of the piezoelectric layer 2 facing the substrate 1, or the interdigitated electrodes 3 can also be located at the side of the piezoelectric layer 2 facing away from the substrate 1 and the side of the piezoelectric layer 2 facing the substrate 1 at the same time; when the interdigitated electrodes 3 are located on the side of the piezoelectric layer 2 facing the substrate 1, the temperature compensation layer 15 can be located on the side of the piezoelectric layer 2 facing away from the substrate 1, or on the side of the piezoelectric layer 2 facing the substrate 1. Layer 2 is located on the side of the piezoelectric layer 2 facing the substrate 1, or is located at the same time on the side of the piezoelectric layer 2 facing the substrate 1 and the side of the piezoelectric layer 2 facing away from the substrate 1; when the interdigitated electrodes 3 are located at the same time on the side of the piezoelectric layer 2 facing away from the substrate 1 and the side of the piezoelectric layer 2 facing the substrate 1, the temperature compensation layer 15 can be located on the side of the piezoelectric layer 2 facing away from the substrate 1, or on the side of the piezoelectric layer 2 facing the substrate 1, or at the same time on the side of the piezoelectric layer 2 facing the substrate 1 and the side of the piezoelectric layer 2 facing away from the substrate 1.

[0071] Optionally, in another embodiment of the present invention, the structure of the interdigital electrode 3 in the above-mentioned pseudo-mode suppression type high-frequency acoustic wave resonator is further described, as follows:

[0072] The first bus bar 4 has a semicircular structure, and the second bus bar 5 has a semicircular structure.

[0073] Specifically, in the embodiment of the present invention, Figure 9 As shown, Figure 9A schematic diagram of a top view of another interdigital electrode provided in an embodiment of the present invention, wherein the first bus bar 4 and the second bus bar 5 in the interdigital electrode 3 are both semicircular structures, and the semicircular structure is composed of a semicircular arc and a diameter corresponding to the semicircular arc; Figure 10 As shown, Figure 10 A schematic diagram of a top-down structure of another interdigitated electrode provided in an embodiment of the present invention, wherein the structures of the first bus bar 4 and the second bus bar 5 in the interdigitated electrode 3 are both trapezoidal structures; it should be noted that the structures of the first bus bar 4 and the second bus bar 5 include but are not limited to semicircular structures or trapezoidal structures, and can also be other geometric structures. This geometric structure has no parallel acoustic boundaries, thereby suppressing the in-phase superposition of sound waves, increasing the energy dissipation of high-order modes, reducing the vibration amplitude of stray sound waves, and further suppressing pseudo-modes.

[0074] The width of the first bus bar 4 in the first direction A is 0.01-10 times the wavelength of the interdigital electrode 3 ; the width of the second bus bar 5 in the first direction A is 0.01-10 times the wavelength of the interdigital electrode 3 .

[0075] Specifically, in an embodiment of the present invention, the width of the first bus bar 4 can take any value in the range of 0.01-10 times the wavelength of the interdigitated electrode 3, and the width of the first bus bar 4 can be 5um or 20um, etc.; the width of the second bus bar 5 can take any value in the range of 0.01-10 times the wavelength of the interdigitated electrode 3, and the width of the second bus bar 5 can be 5um or 20um, etc.

[0076] The length of the first pseudo electrode finger 7 in the first direction A is 0.5-10 times the wavelength of the interdigitated electrode 3, and the length of the second pseudo electrode finger 9 in the first direction A is 0.5-10 times the wavelength of the interdigitated electrode 3; the length of the first electrode finger 6 in the first direction A is 8-40 times the wavelength of the interdigitated electrode 3, and / or the length of the second electrode finger 8 in the first direction A is 8-40 times the wavelength of the interdigitated electrode 3; in the first direction A, the length of the first pseudo electrode finger 7 is smaller than the length of the first electrode finger 6, and the length of the second pseudo electrode finger 9 is smaller than the length of the second electrode finger 8.

[0077] Specifically, in an embodiment of the present invention, the length of the first pseudo electrode finger 7 is preferably 1-1.5 times the wavelength of the interdigitated electrode 3, and the length of the first pseudo electrode finger 7 can take any value within the range of 1-1.5 times the wavelength of the interdigitated electrode 3. The length of the first pseudo electrode finger 7 can take a value of 30um or 35um, etc.; the length of the second pseudo electrode finger 9 is preferably 1-1.5 times the wavelength of the interdigitated electrode 3, and the length of the second pseudo electrode finger 9 can take any value within the range of 1-1.5 times the wavelength of the interdigitated electrode 3. The length of the second pseudo electrode finger 9 can take a value of The value is 30um or 35um, etc.; the length of the first electrode finger 6 and the second electrode finger 8 can take any value in the range of 8-40 times the wavelength of the interdigitated electrode 3, respectively, and the length of the first electrode finger 6 can take a value of 120um or 160um, etc., and the length of the second electrode finger 8 can take a value of 120um or 160um, etc.; or the total length of the first electrode finger 6 and the second electrode finger 8 can take any value in the range of 8-40 times the wavelength of the interdigitated electrode 3, and the total length of the first electrode finger 6 and the second electrode finger 8 can take a value of 120um or 160um, etc.

[0078] The spacing between the first electrode finger 6 and the second dummy electrode finger 9 is 0.2-5 times the wavelength of the interdigital electrode 3 ; the spacing between the first dummy electrode finger 7 and the second electrode finger 8 is 0.2-5 times the wavelength of the interdigital electrode 3 .

[0079] Specifically, in an embodiment of the present invention, the spacing between the first electrode finger 6 and the second pseudo-electrode finger 9 can take any value in the range of 0.2-5 times the wavelength of the interdigitated electrode 3, and the spacing between the first electrode finger 6 and the second pseudo-electrode finger 9 can take a value of 8um or 30um, etc.; the spacing between the first pseudo-electrode finger 7 and the second electrode finger 8 can take any value in the range of 0.2-5 times the wavelength of the interdigitated electrode 3, and the spacing between the first pseudo-electrode finger 7 and the second electrode finger 8 can take a value of 8um or 30um, etc.

[0080] It should be noted that in an embodiment of the present invention, in the first direction A, the lengths of the electrode fingers in the first electrode finger 6 may be different, the lengths of the electrode fingers in the first pseudo electrode finger 7 may be different, the lengths of the electrode fingers in the second electrode finger 8 may be different, and the lengths of the electrode fingers in the second pseudo electrode finger 9 may be different, thereby making the arrangement of the electrode fingers more flexible; but it is required that the length of the first pseudo electrode finger 7 is less than the length of the first electrode finger 6, and the length of the second pseudo electrode finger 9 is less than the length of the second electrode finger 8.

[0081] Optionally, in another embodiment of the present invention, the materials and thicknesses of the various structures in the above-mentioned pseudo-mode suppression type high-frequency acoustic wave resonator are further described, as follows:

[0082] In the embodiment of the present invention, the material of the substrate 1 includes but is not limited to silicon, sapphire, gallium nitride, silicon carbide, high-resistance silicon and the like.

[0083] The material of the piezoelectric layer 2 includes but is not limited to lithium niobate, lithium tantalate, scandium-doped aluminum nitride, aluminum nitride and the like, or can be a combination of the above materials; the thickness of the piezoelectric layer 2 in the first direction A can take any value within the range of 10nm-5000nm. In the embodiment of the present invention, the thickness of the piezoelectric layer 2 can take a value of 300nm or 700nm, etc.

[0084] The material of the release layer 13 includes but is not limited to silicon dioxide, silicon oxide, silicon, lithium niobate, germanium, quartz, sapphire and the like; the thickness of the release layer 13 in the first direction A can take any value within the range of 0.01um-50um. In the embodiment of the present invention, the thickness of the release layer 13 can take a value of 3um or 10um, etc.

[0085] The material of the interdigital electrode 3 includes but is not limited to molybdenum, aluminum, tungsten, titanium, copper, silver and gold, or a combination of the above materials; the thickness of the interdigital electrode 3 in the first direction A can take any value in the range of 10nm-5000nm. In the embodiment of the present invention, the thickness of the interdigital electrode 3 can take a value of 20nm or 200nm.

[0086] The number of the interdigital electrodes 3 can take any value in the range of 2-400. In the embodiment of the present invention, the number of the interdigital electrodes 3 is preferably 5 or 50. The spacing between two adjacent interdigital electrodes 3 in the first direction A can take any value in the range of 0.1um-30um. In the embodiment of the present invention, the spacing between two adjacent interdigital electrodes 3 in the first direction A can take a value of 4um or 10um, etc. The width B of each of the interdigital electrodes 4 in the second direction can take any value in the range of 0.1um-15um. In the embodiment of the present invention, the width B of each of the interdigital electrodes 4 in the second direction can take a value of 2um or 5um, etc.

[0087] The above is a detailed introduction to a pseudo-mode suppressed high-frequency acoustic wave resonator provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

[0088] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0089] It should also be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that the process, method, article, or apparatus comprising a series of elements inherent to the elements, or also including elements inherent to these processes, methods, articles, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0090] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A pseudo-mode suppression type high-frequency acoustic wave resonator, characterized in that: The high-frequency acoustic wave resonator comprises: substrate; a piezoelectric layer located on one side of the substrate; a plurality of interdigital electrodes located on a side of the piezoelectric layer facing away from the substrate; The interdigitated electrode includes a first bus bar and a second bus bar arranged opposite to each other in a first direction, and a plurality of electrode fingers located between the first bus bar and the second bus bar, the electrode fingers including a first electrode and a second electrode; In the second direction, the first electrode includes a plurality of first electrode fingers and a plurality of first dummy electrode fingers alternately arranged on a side of the first bus bar facing the second bus bar, and the second electrode includes a plurality of second electrode fingers and a plurality of second dummy electrode fingers alternately arranged on a side of the second bus bar facing the first bus bar, the first direction and the second direction are both parallel to the plane of the substrate, and the second direction is perpendicular to the first direction; The first electrode finger and the second dummy electrode finger are arranged opposite to each other in the first direction, the first dummy electrode finger and the second electrode finger are arranged opposite to each other in the first direction, a first-level gap point exists between the first electrode finger and the second dummy electrode finger, and a second-level gap point exists between the first dummy electrode finger and the second electrode finger; Wherein, a plurality of the first-level gap points and a plurality of the second-level gap points are sequentially connected as vertices to form a virtual polygon, and any two sides of the virtual polygon are not parallel to each other.

2. The high-frequency acoustic wave resonator according to claim 1, characterized in that The virtual polygon is a five-vertex polygon, and the internal angles of the five-vertex polygon are all smaller than 180°.

3. The high-frequency acoustic wave resonator according to claim 1, characterized in that The high-frequency acoustic wave resonator further comprises: a release layer between the substrate and the piezoelectric layer; a plurality of through holes extending through the piezoelectric layer; An air cavity is located between the substrate and the piezoelectric layer, and the air cavity is communicated with the through hole.

4. The high-frequency acoustic wave resonator according to claim 1, characterized in that The high-frequency acoustic wave resonator further includes: a temperature compensation layer; The temperature compensation layer is located on a side of the piezoelectric layer facing away from the substrate; And / or the temperature compensation layer is located on a side of the piezoelectric layer facing the substrate.

5. The high-frequency acoustic wave resonator according to claim 1, characterized in that The electric field direction formed by the interdigitated electrodes forms an Euler angle θ with respect to the +Y axis direction of the piezoelectric layer in the global coordinate system, and the value range of the Euler angle θ is -40° to +40°; The interdigital electrodes are arranged on a side of the piezoelectric layer facing away from the substrate based on the Euler angle θ.

6. The high-frequency acoustic wave resonator according to claim 1, characterized in that The first bus bar has a semicircular structure; the second bus bar has a semicircular structure.

7. The high-frequency acoustic wave resonator according to claim 1, characterized in that The width of the first bus bar in the first direction is 0.01-10 times the wavelength of the interdigital electrodes; The width of the second bus bar in the first direction is 0.01-10 times the wavelength of the interdigital electrodes.

8. The high-frequency acoustic wave resonator according to claim 1, characterized in that The length of the first dummy electrode finger in the first direction is 0.5-10 times the wavelength of the interdigital electrode, and the length of the second dummy electrode finger in the first direction is 0.5-10 times the wavelength of the interdigital electrode; The length of the first electrode finger in the first direction is 8-40 times the wavelength of the interdigital electrode, and / or the length of the second electrode finger in the first direction is 8-40 times the wavelength of the interdigital electrode; In the first direction, the length of the first dummy electrode finger is smaller than the length of the first electrode finger, and the length of the second dummy electrode finger is smaller than the length of the second electrode finger.

9. The high-frequency acoustic wave resonator according to claim 1, characterized in that The spacing between the first electrode finger and the second dummy electrode finger is 0.2-5 times the wavelength of the interdigital electrode; The distance between the first dummy electrode fingers and the second electrode fingers is 0.2-5 times the wavelength of the interdigital electrodes.

10. The high-frequency acoustic wave resonator according to claim 1, characterized in that The thickness of the piezoelectric layer ranges from 10 nm to 5000 nm; The thickness of the interdigital electrodes ranges from 10 nm to 5000 nm; The number of the interdigital electrodes ranges from 2 to 400; The distance between two adjacent interdigital electrodes ranges from 0.1 μm to 30 μm. The width of each of the interdigital electrodes in the second direction ranges from 0.1 um to 15 um.

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