Resonator, filter, and electronic device

Abstract

The invention discloses a resonator, a filter and an electronic device, and belongs to the technical field of semiconductors. The resonator comprises a substrate which comprises an electrode finger region, bus regions located on the two opposite sides of the electrode finger region in the first direction, and gap regions located between the electrode finger region and the bus regions; the piezoelectric layer is positioned in the electrode finger region and the gap region, and is positioned on one side of the substrate along the second direction; an opening is formed in the edge of the piezoelectric layer, the opening is at least located in the gap area, and at least part of an interface between the piezoelectric layer and the opening tends to incline towards the direction of the electrode finger area; the first direction is perpendicular to the second direction; and the electrode layer is positioned in the electrode finger region, the gap region and the bus region, and is positioned on one side, deviating from the substrate, of the piezoelectric layer. According to the invention, a spurious mode can be suppressed, and the performance of the resonator is improved.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor technology, and in particular relates to a resonator, a filter and an electronic device. Background Art

[0002] Resonators are widely used in mobile communication devices, with advantages such as low insertion loss, wide bandwidth, small size, low cost, and mass production. However, when the main mode is excited, the resonator will also generate unnecessary spurious modes (such as spurious generated by the lateral mode perpendicular to the main mode), and the spurious modes will affect the performance of the resonator. Summary of the invention

[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a resonator, a filter and an electronic device, which can suppress spurious modes and improve the performance of the resonator.

[0004] In a first aspect, the present application provides a resonator, comprising:

[0005] A substrate, comprising an electrode finger region, a bus bar region located at two opposite sides of the electrode finger region along a first direction, and a gap region located between the electrode finger region and the bus bar region;

[0006] a piezoelectric layer located in the electrode finger region and the gap region, and located on one side of the substrate along the second direction; an edge of the piezoelectric layer has an opening, the opening is at least located in the gap region, and at least part of the interface between the piezoelectric layer and the opening is inclined toward the electrode finger region; the first direction is perpendicular to the second direction, and the second direction is the thickness direction of the substrate;

[0007] The electrode layer is located in the electrode finger region, the gap region and the busbar region, and is located on a side of the piezoelectric layer away from the substrate.

[0008] According to the resonator of the present application, an opening is provided at the edge of the piezoelectric layer so that the opening is at least located in the gap region, and at least a portion of the interface between the piezoelectric layer and the opening tends to be inclined in the direction of the electrode finger region, so as to reflect the stray mode transmitted to the gap region to the substrate and avoid the stray mode being reflected back to the electrode finger region, thereby suppressing the stray mode while ensuring the main mode propagation characteristics and improving the performance of the resonator.

[0009] According to an embodiment of the present application, the opening extends from a side of the piezoelectric layer facing away from the substrate into the piezoelectric layer along the second direction, or the opening penetrates the piezoelectric layer along the second direction.

[0010] According to one embodiment of the present application, an orthographic projection of a top of the opening on the substrate coincides with the gap region.

[0011] According to one embodiment of the present application, the electrode finger region includes an edge region close to the gap region;

[0012] The openings are located in the gap region and the edge region.

[0013] According to one embodiment of the present application, the opening includes a first sub-opening and a second sub-opening that are connected;

[0014] The first sub-opening is at least located in the gap region, the interface between the piezoelectric layer and the first sub-opening tends to be inclined toward the electrode finger region, and the second sub-opening is located on a side of the piezoelectric layer close to the first sub-opening.

[0015] According to one embodiment of the present application, the second sub-opening is located at the bottom of the first sub-opening.

[0016] According to an embodiment of the present application, the electrode layer includes electrode fingers located in the electrode finger region and extending along the first direction;

[0017] The electrode fingers also extend to a portion of the interface between the piezoelectric layer and the opening.

[0018] According to one embodiment of the present application, the resonator further includes a first dielectric layer;

[0019] The first dielectric layer is filled in the opening.

[0020] According to one embodiment of the present application, the first dielectric layer is a single-layer structure or a stacked-layer structure.

[0021] According to one embodiment of the present application, at least a portion of the interface between the piezoelectric layer and the opening is covered by the same film layer.

[0022] According to one embodiment of the present application, at least a portion of the interface between the piezoelectric layer and the opening includes at least one of a plane, a curved surface, and a fold line surface, and the fold line surface includes a step surface.

[0023] According to one embodiment of the present application, the piezoelectric layer includes lithium tantalate, and the inclination angle of at least a portion of the interface between the piezoelectric layer and the opening is between 5° and 30°.

[0024] According to one embodiment of the present application, the resonator further includes a second dielectric layer;

[0025] The second dielectric layer is located in the busbar region and between the substrate and the electrode layer.

[0026] In a second aspect, the present application provides a filter, comprising the resonator as described in the first aspect above.

[0027] In a third aspect, the present application provides an electronic device, comprising the filter as described in the second aspect above.

[0028] The above one or more technical solutions in the embodiments of the present application have at least one of the following technical effects:

[0029] By arranging an opening at the edge of the piezoelectric layer, the opening is at least located in the gap area, and at least part of the interface between the piezoelectric layer and the opening tends to be inclined toward the electrode finger area, so as to reflect the stray mode transmitted to the gap area to the substrate and avoid the stray mode being reflected back to the electrode finger area, thereby ensuring the main mode propagation characteristics while suppressing the stray mode and improving the performance of the resonator.

[0030] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0032] Figure 1 It is one of the structural schematic diagrams of the resonator provided in the embodiment of the present application;

[0033] Figure 2 is a top view of a resonator provided in an embodiment of the present application;

[0034] Figure 3 This is the second structural schematic diagram of the resonator provided in the embodiment of the present application;

[0035] Figure 4 It is one of the principle schematic diagrams of the resonator provided in the embodiment of the present application;

[0036] Figure 5 This is the second principle schematic diagram of the resonator provided in the embodiment of the present application;

[0037] Figure 6 This is one of the curve relationship diagrams of frequency and conductance of the resonator at different tilt angles provided in the embodiment of the present application;

[0038] Figure 7 is one of the curve relationship diagrams of frequency and admittance of the resonator provided in the embodiment of the present application;

[0039] Figure 8 This is the second graph of the relationship between the frequency and the admittance of the resonator provided in the embodiment of the present application;

[0040] Fig. 9 is a curve relationship diagram of frequency and conductance of the resonator provided by the embodiment of the present application when the gap width is different;

[0041] Fig.10 is a curve relationship diagram of frequency and conductance of the resonator provided by the embodiment of the present application when the thickness of the piezoelectric layer is different;

[0042] Fig.11 is a curve relationship diagram of frequency and admittance of the resonator provided in the embodiment of the present application when the thickness of the piezoelectric layer is different;

[0043] Fig.12 is a curve relationship diagram of frequency and conductance of the resonator provided in the embodiment of the present application at different apertures;

[0044] Fig.13 is a curve relationship diagram of the frequency and mechanical Q value of the resonator provided in the embodiment of the present application at different tilt angles;

[0045] Fig.14 is a curve relationship diagram of the tilt angle, wave speed and k2 in the resonator provided in the embodiment of the present application;

[0046] Fig.15 This is the third structural schematic diagram of the resonator provided in the embodiment of the present application;

[0047] Fig.16 This is the fourth structural schematic diagram of the resonator provided in the embodiment of the present application;

[0048] Fig.17 This is the fifth structural diagram of the resonator provided in the embodiment of the present application;

[0049] Fig.18 is a curve relationship diagram of frequency and conductance of the resonator provided in the embodiment of the present application at different L1;

[0050] Fig.19 This is the sixth structural schematic diagram of the resonator provided in the embodiment of the present application;

[0051] Fig. 20 is a curve relationship diagram of frequency and conductance of the resonator provided in the embodiment of the present application at different L2;

[0052] Fig.21 This is the second graph of the relationship between frequency and conductance of the resonator at different tilt angles provided in the embodiment of the present application;

[0053] Fig. 22 This is the seventh structural diagram of the resonator provided in the embodiment of the present application;

[0054] Fig.23 This is the eighth structural schematic diagram of the resonator provided in the embodiment of the present application;

[0055] Fig.24 This is the ninth structural diagram of the resonator provided in the embodiment of the present application;

[0056] Fig.25 This is the tenth structural diagram of the resonator provided in the embodiment of the present application;

[0057] Fig.26 This is the eleventh structural diagram of the resonator provided in the embodiment of the present application;

[0058] Fig. 27 This is the twelfth structural schematic diagram of the resonator provided in the embodiment of the present application. DETAILED DESCRIPTION

[0059] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0060] The resonator, filter and electronic device provided by the embodiments of the present application are described below with reference to the accompanying drawings.

[0061] Figure 1 A schematic diagram of the structure of a resonator provided in an embodiment of the present application. The resonator may be a surface acoustic wave (SAW) resonator or a bulk acoustic wave (BAW) resonator. For example, the resonator may be a solid-state mounted resonator (SMR) resonator, a transversely excited bulk acoustic wave resonator (XBAR), a shear wave resonator (YBAR), a POI (piezoelectric film on insulator) resonator, etc.

[0062] like Figure 1 As shown, the resonator includes a substrate 1, a piezoelectric layer 2 and an electrode layer 3. The substrate 1, the piezoelectric layer 2 and the electrode layer 3 are arranged in sequence along a second direction Y, and the second direction Y is a thickness direction of the substrate 1.

[0063] The substrate 1 includes a device region for arranging devices (such as surface acoustic wave devices or bulk acoustic wave devices). The device region includes an electrode finger region 10, a busbar region 30 located on opposite sides of the electrode finger region 10 along a first direction X, and a gap region 20 located between the electrode finger region 10 and the busbar region 30. The first direction X is perpendicular to the second direction Y.

[0064] Combination Figure 2As shown, the busbar region 30 may include a first busbar sub-region 30a and a second busbar sub-region 30b, and the first busbar sub-region 30a and the second busbar sub-region 30b are respectively located at opposite sides of the electrode finger region 10 along the first direction X. The gap region 20 may include a first gap sub-region 20a and a second gap sub-region 20b, and the first gap sub-region 20a is located between the electrode finger region 10 and the first busbar sub-region 30a, and the second gap sub-region 20b is located between the electrode finger region 10 and the second busbar sub-region 30b.

[0065] In some embodiments, Figure 1 As shown, the base 1 may include a substrate 11 and a support layer 12. The support layer 12 is located on one side of the substrate 11 along the second direction Y. The substrate 1 may include a silicon substrate, etc. The support layer 12 may include silicon oxide, such as silicon dioxide. According to actual needs, the base 1 may also include other film layers, which are not specifically limited here.

[0066] The piezoelectric layer 2 is located on one side of the substrate 1 along the second direction Y, and the piezoelectric layer 2 is located in the electrode finger region 10 and the gap region 20. In the case where the substrate 1 includes a substrate 11 and a support layer 12, the piezoelectric layer 2 is located on the side of the support layer 12 away from the substrate 11. The piezoelectric layer 2 may include lithium tantalate (LiTaO 3 )wait.

[0067] The piezoelectric layer 2 has an opening 4, which is located at the edge of the piezoelectric layer 2, and the opening 4 is at least located in the gap region 20. The opening 4 may be located only in the gap region 20 (the opening 4 may be located in part of the gap region 20, or in the entire gap region 20), or may be located in the gap region 20 and the electrode finger region 10. In the case where the opening 4 is located in the gap region 20, the electrode finger region 10 may be located in the gap region 20. Figure 2 As shown, the opening 4 may be located in the first gap sub-region 20a, the second gap sub-region 20b, or both. When the opening 4 is located in the first gap sub-region 20a and the second gap sub-region 20b, the shapes and sizes of the opening 4 in the first gap sub-region 20a and the opening 4 in the second gap sub-region 20b may be the same or different.

[0068] At least part of the interface between the piezoelectric layer 2 and the opening 4 has a tendency to tilt toward the electrode finger region 20. When the opening 4 is located in the first gap sub-region 20a, at least part of the interface between the piezoelectric layer 2 and the opening 4 in the first gap sub-region 20a has a tendency to tilt toward the electrode finger region 20; when the opening 4 is located in the second gap sub-region 20b, at least part of the interface between the piezoelectric layer 2 and the opening 4 in the second gap sub-region 20b has a tendency to tilt toward the electrode finger region 20.

[0069] The electrode layer 3 is located on the side of the piezoelectric layer 2 facing away from the substrate 1 , and the electrode layer 3 is located in the electrode finger region 10 , the gap region 20 and the busbar region 30 , that is, the electrode layer 3 is located in the device region.

[0070] In some embodiments, in combination Figure 2 As shown, the electrode layer 3 includes a plurality of electrode fingers, a first busbar 33 and a second busbar 34. The first busbar 33 and the second busbar 34 are both located in the busbar region 30 and extend along the third direction Z, and the third direction Z is perpendicular to the first direction X and the second direction Y, respectively. The first busbar 33 is located in the first busbar sub-region 30a, and the second busbar 34 is located in the second busbar sub-region 30b. The plurality of electrode fingers include first electrode fingers 31 and second electrode fingers 32 that are alternately and spaced along the third direction Z. The first electrode fingers 31 and the second electrode fingers 32 are both located in the electrode finger region 10 and extend along the first direction X. The first electrode finger 31 extends from the electrode finger region 10 along the first direction X to the first gap sub-region 20a, and is connected to the first busbar 33, that is, the first electrode finger 31 is located in the electrode finger region 10 and the first gap sub-region 20a. The second electrode fingers 32 extend from the electrode finger region 10 along the first direction X to the second gap sub-region 20 b and are connected to the second bus bar 34 , that is, the second electrode fingers 32 are located in the electrode finger region 10 and the second gap sub-region 20 b .

[0071] The number of the first electrode fingers 31 and the second electrode fingers 32 may be the same. The sizes (including length and width, etc.) of the first electrode fingers 31 and the second electrode fingers 32 may be the same. The materials of the first electrode fingers 31 and the second electrode fingers 32 may both include metal materials such as copper and aluminum. The first busbar 33 and the second busbar 34 may be used as connecting wires connecting adjacent resonators or connecting wires connecting the package side. The materials of the first busbar 33 and the second busbar 34 may both include metal materials such as copper and aluminum.

[0072] This embodiment does not need to change the size of the resonator or the structure of the electrode layer. Only the opening 4 is set at the edge of the piezoelectric layer 2, so that the opening 4 is at least located in the gap area 20, and at least part of the interface between the piezoelectric layer 2 and the opening 4 is inclined toward the electrode finger area 10, so that the stray mode transmitted to the gap area 20 can be reflected to the substrate 1, thereby suppressing the stray mode while ensuring the main mode transmission characteristics, improving the Q value of the resonator, better suppressing the acoustic energy and reducing the scattering loss, and improving the performance of the resonator. Moreover, this embodiment can be used in combination with other stray suppression methods (such as piston mode IDT, slowness curve optimization) to further improve the stray suppression effect.

[0073] In some embodiments, Figure 2 and Figure 3As shown, the resonator further includes a first dielectric layer 5, which is filled in the opening 4, that is, the first dielectric layer 5 is located on the side of the piezoelectric layer 2, and the first dielectric layer 5 is at least located in the gap area 20. The at least partial interface between the piezoelectric layer 2 and the opening 4 includes a partial interface between the piezoelectric layer 2 and the first dielectric layer 5, that is, at least a partial interface between the piezoelectric layer 2 and the first dielectric layer 5 tends to be inclined toward the electrode finger area 10. The first dielectric layer 5 may include SiO 2 、Si 3 N 4 、Al 2 O 3 、 2 O 5 , ALN, SiC, etc. The first dielectric layer 5 may also include a piezoelectric layer of a material different from that of the piezoelectric layer 2, or a doped piezoelectric layer, as long as the first dielectric layer 5 and the piezoelectric layer 2 are two different media, which is not specifically limited here.

[0074] In this embodiment, a first dielectric layer 5 is disposed on the side of the piezoelectric layer 2. The first dielectric layer 5 is at least located in the gap area 20, and at least part of the interface between the piezoelectric layer 2 and the first dielectric layer 5 tends to be inclined toward the electrode finger area 10. The stray mode transmitted to the gap area 20 can be reflected to the substrate 1, thereby suppressing the stray mode while ensuring the main mode transmission characteristics, thereby improving the performance of the resonator.

[0075] It should be noted that by adjusting the inclination angle of at least part of the interface between the piezoelectric layer 2 and the opening 4, all stray modes can be attenuated and leaked to the substrate 1, avoiding the stray modes from returning to the piezoelectric layer 2, so as to effectively suppress the stray modes in a wide frequency range.

[0076] like Figure 4 As shown, the transverse mode TM is transmitted to the interface between the piezoelectric layer 2 and the first dielectric layer 5, and a transmitted wave S1 and a reflected wave S2 are generated at the same time. Usually, the propagation directions of the transmitted wave S1 and the reflected wave S2 are different. Due to multiple reflections, part of the wave will return to the piezoelectric layer 2 as a stray mode, and the stray mode cannot be completely suppressed. Figure 5 As shown, by adjusting the inclination angle θ of at least part of the interface between the piezoelectric layer 2 and the first dielectric layer 5, total internal reflection occurs, and both the transmitted wave S1 and the reflected wave S2 propagate to the substrate 1, preventing the stray mode from returning to the piezoelectric layer 2, so as to completely suppress the stray mode in a wide frequency range.

[0077] The optimal value of the tilt angle θ depends on the anisotropy, crystal orientation and acoustic wave propagation characteristics of the piezoelectric layer 2. The optimal value of the tilt angle θ can be calculated based on the wave velocity in the piezoelectric layer 2 and the first dielectric layer 5 and the initial scattering angle of the transverse mode TM. However, in anisotropic media, these parameters are highly dependent on direction and difficult to obtain. Therefore, the initial value of the tilt angle θ can be calculated first, and then the tilt angle θ can be optimized based on the three-dimensional finite element model (3D FEM model) of the resonator to obtain the optimal value of the tilt angle θ.

[0078] For example, the substrate 11 includes silicon, the support layer 12 includes silicon dioxide, the piezoelectric layer 2 includes a Y-cut LT material, the electrode layer includes aluminum, the wavelength λ is 1.9 μm, the duty factor DF of the electrode finger (the ratio of the electrode finger width to the electrode finger spacing) is 0.5, and the width of the gap region (the width G of the first gap sub-region 20a and the width G of the second gap sub-region 20b) is fixed to 2λ. The tilt angle θ is adjusted between 0 and 90°, and the conductivity characteristics of the resonator are detected respectively, such as Figure 6 As shown. It can be seen that the optimal value of the tilt angle θ is between 8° and 10°, that is, when the tilt angle θ is between 8° and 10°, the resonator has a better spurious suppression effect. Figure 7 and Figure 8 As shown, Figure 7 is a schematic diagram of the frequency and admittance of the resonator when the tilt angle θ is 3°. Figure 8 Figure 1 is a schematic diagram of the frequency and admittance of the resonator when the tilt angle θ is 10°. It can be seen that the resonator has a better spurious suppression effect when the tilt angle θ is 10°.

[0079] The optimal value of the tilt angle θ changes as the structural parameters and film material in the resonator change. For any resonator, the optimal value of the tilt angle θ is between 5° and 15° or between 2° and 45°.

[0080] In addition, the tilt angle θ is fixed to 10°, the width of the gap region (the width G of the first gap sub-region 20a and the width G of the second gap sub-region 20b) is adjusted between 0.5λ and 4.0λ, and the conductive characteristics of the resonator are detected respectively, such as Fig. 9 As shown in Figure 2, it can be seen that the width of the gap region has no significant effect on the suppression of spurious modes.

[0081] The tilt angle θ is fixed to 10°, and the width of the gap region (the width G of the first gap sub-region 20a and the width G of the second gap sub-region 20b) is fixed to 2λ, the thickness H of the piezoelectric layer 2 is adjusted between 300nm and 1000nm, and the conductivity characteristics of the resonator are detected respectively, such as Fig.10 As shown. It can be seen that the thickness H of the piezoelectric layer 2 has no obvious effect on the suppression of stray modes. In addition, combined with Fig.11 As shown, Fig.11 The figure shows the relationship between the frequency and admittance of the resonator when the tilt angle θ is fixed at 10° and the thickness H of the piezoelectric layer 2 is 0.3μm, 0.6μm and 0.9μm respectively. It can be seen that when the tilt angle θ is 10°, no matter how the thickness of the piezoelectric layer 2 is adjusted, the resonator can achieve good spurious suppression.

[0082] The resonator aperture has a great influence on the spectrum and intensity of the transverse mode. Generally, the high-order mode intensity of a resonator with a relatively small aperture (such as less than 20λ) decreases, while the low-order mode intensity increases. When high-frequency spurious modes appear near the resonant frequency, it is difficult to suppress the spurious modes well. Therefore, this embodiment evaluates the conductivity characteristics of resonators with different apertures. The tilt angle θ is fixed to 10°, and the width of the gap region (the width G of the first gap sub-region 20a and the width G of the second gap sub-region 20b) is fixed to 2λ, the resonator aperture D is adjusted between 5λ and 60λ, and the conductivity characteristics of the resonator are detected respectively, such as Fig.12 It can be seen that when the resonator aperture D is less than 10λ, the spurious mode can be well suppressed.

[0083] Fig.13 The figure is a schematic diagram of the relationship between the frequency of the resonator and the mechanical Q value of the piezoelectric layer when the tilt angle θ is 3°, 10° and 80° respectively. It can be seen that when the tilt angle θ is 3° and 10°, the influence on the main mode energy confinement and Q value is small. When the tilt angle θ is greater than 45°, the Q value may decrease when it is lower than the resonance frequency due to the leakage of the sound wave to the first dielectric layer. Therefore, by adjusting the tilt angle θ, it can be ensured that the influence on the main mode energy confinement and Q value is small or no influence.

[0084] like Fig.14 As shown, Fig.14 Figure 1 is a schematic diagram of the relationship between the tilt angle θ and the wave velocity and the electromechanical coupling coefficient k2. It can be seen that the wave velocity and k2 have little effect on the tilt angle θ. In a larger range of tilt angles θ, the wave velocity remains almost unchanged, while k2 decreases slightly. By adjusting the tilt angle θ, it can be ensured that the attenuation of k2 is less than 0.2%, which is comparable to the normal deviation of the parameters.

[0085] In some embodiments, the piezoelectric layer 2 includes lithium tantalate (LT), and the at least partial interface between the piezoelectric layer 2 and the opening 4 is inclined at an angle between 5° and 30°, that is, 5°≤θ≤30°.

[0086] In some embodiments, Figure 3 and Fig.15 As shown, the first dielectric layer 5 can be a single-layer structure. Fig.16As shown, the first dielectric layer 5 may be a laminated structure. In the case where the first dielectric layer 5 is a laminated structure, the first dielectric layer 5 includes a plurality of film layers, and the number of film layers is not specifically limited. The materials and thicknesses of the plurality of film layers may be the same or different. The stacking direction of the plurality of film layers may be parallel to the first direction X, or may intersect with the first direction X, which is not specifically limited here.

[0087] In some embodiments, when the first dielectric layer 5 is a stacked structure, at least a portion of the interface between the piezoelectric layer 2 and the opening 2 is covered by the same film layer.

[0088] like Fig.16 As shown, the first dielectric layer 5 may include a first film layer 51 and a second film layer 52. The second film layer 52 is located in the opening 2 and covers the side wall of the piezoelectric layer 2 close to the opening 2, and the first film layer 52 fills the opening 2.

[0089] In this embodiment, the first dielectric layer 5 is a laminated structure, and the acoustic characteristics of the gap region can be adjusted according to different film layers to further improve the suppression effect of the stray mode.

[0090] In some embodiments, Figure 1 and Figure 3 As shown, the opening 4 can extend from the side of the piezoelectric layer 2 away from the substrate 1 along the second direction Y into the piezoelectric layer 2, that is, the opening 4 does not penetrate the piezoelectric layer 2 along the second direction Y, so that part of the surface of the piezoelectric layer 2 on the opposite sides along the first direction X tends to be inclined toward the direction of the electrode finger area 10, and the stray mode transmitted to the gap area 20 is reflected to the substrate to suppress the stray.

[0091] like Fig.15 and Fig.16 As shown, the opening 4 may also penetrate the piezoelectric layer 2 along the second direction Y, so that at least part of the surface (such as the entire surface) of the piezoelectric layer 2 on the opposite sides along the first direction X tends to be inclined toward the electrode finger area 10, and more stray modes transmitted to the gap area 20 are reflected to the substrate 1 to suppress more stray modes.

[0092] In the case where the opening 4 is located in the first gap sub-region 20a and the second gap sub-region 20b, the opening 4 of the first gap sub-region 20a may extend from the side of the piezoelectric layer 2 away from the substrate 1 along the second direction Y to the inside of the piezoelectric layer 2 or penetrate the piezoelectric layer 2, and the opening 4 of the second gap sub-region 20b may extend from the side of the piezoelectric layer 2 away from the substrate 1 along the second direction Y to the inside of the piezoelectric layer 2 or penetrate the piezoelectric layer 2. The extension lengths of the opening 4 of the first gap sub-region 20a and the opening 4 of the second gap sub-region 20b along the second direction Y may be the same or different.

[0093] When the first dielectric layer 5 is filled in the opening 4 , the first dielectric layer 5 extends along the second direction Y from the side of the piezoelectric layer 2 facing away from the substrate 1 into the piezoelectric layer 2 , or the first dielectric layer 5 penetrates the piezoelectric layer 2 along the second direction Y.

[0094] In some embodiments, Figure 1 , Figure 3 , Fig.15 and Fig.16 As shown, the orthographic projection of the top of the opening 4 (the end of the opening 4 facing away from the substrate 1) on the substrate 1 coincides with the gap region 20, that is, the orthographic projection of the top of the opening 4 on the substrate 1 completely covers the gap region 20. In the case where the opening 4 is filled with the first dielectric layer 5, the orthographic projection of the upper surface of the first dielectric layer 5 (the surface of the first dielectric layer 5 facing away from the substrate 1) on the substrate 1 completely covers the gap region 20.

[0095] In some embodiments, Fig.17 As shown, the orthographic projection of the top of the opening 4 on the substrate 1 covers part of the gap region 20. When the first dielectric layer 5 is filled in the opening 4, the orthographic projection of the upper surface of the first dielectric layer 5 on the substrate 1 covers part of the gap region 20.

[0096] In order to ensure that the tilt angle θ is the optimal value, the length of the electrode finger along the first direction X can be shortened and the width of the gap region 20 along the first direction X can be increased so that the orthographic projection of the top of the opening 4 on the substrate 1 covers part of the gap region 20. The upper surface of the first dielectric layer 5 and the electrode finger region 10 have a spacing L1, that is, the shortened length of the electrode finger along the first direction X is L1.

[0097] like Fig.18 As shown, the tilt angle θ is fixed to 10°, L1 is adjusted between 0λ and 3λ, and the conductivity characteristics of the resonator are detected respectively. It can be seen that when L1 is greater than 0, the spurious suppression effect of the resonator is weakened, but compared with the related art, this embodiment still has a certain suppression effect on the spurious mode.

[0098] In some embodiments, Fig.19 As shown, the electrode finger region 10 includes an edge region 40 disposed near the gap region 20, and the opening 4 is located in the gap region 20 and the edge region 40. The orthographic projection of the top of the opening 4 on the substrate 1 can cover the entire gap region 20 and at least a portion of the edge region 40. In the case where the first dielectric layer 5 is filled in the opening 4, the first dielectric layer 5 can be located in the gap region 20 and the edge region 40. The orthographic projection of the upper surface of the first dielectric layer 5 on the substrate 1 can cover the entire gap region 20 and at least a portion of the edge region 40.

[0099] The electrode finger region 10 further includes a main body region 50, and the edge region 40 is located at two opposite sides of the main body region 50 along the first direction X, that is, the edge region 40 is located between the main body region 50 and the first gap sub-region 20a and between the main body region 50 and the second gap sub-region 20b. The opening 4 can be located in the edge region 40 and the gap region 20 on any side of the main body region 50, or in the edge region 40 and the gap region 20 on both sides of the main body region 50.

[0100] In order to ensure that the tilt angle θ is the optimal value, the length of the electrode finger along the first direction X can be extended and the width of the gap area 20 along the first direction X can be reduced so that the orthographic projection of the top of the opening 4 on the substrate 1 covers the entire gap area 20 and at least part of the edge area 40. The length of the upper surface of the first dielectric layer 5 in the edge area 40 is L2, that is, the length of the extended electrode finger is L2.

[0101] like Fig. 20 As shown, the tilt angle θ is fixed to 10°, L2 is adjusted between 0λ and 2λ, and the conductivity characteristics of the resonator are detected respectively. It can be seen that the stray suppression effect of the resonator is slightly weakened. When L2 is less than or equal to 0.25λ, the weakening of the stray suppression effect of the resonator can be ignored, that is, the resonator has a good stray suppression effect.

[0102] By adjusting the tilt angle θ, complete suppression of spurious modes can be achieved. Fig.21 As shown in the figure, L2 is fixed to 0.5λ, the tilt angle θ is adjusted in the range of 5° to 15°, and the conductivity characteristics of the resonator are detected respectively. It can be seen that the optimal value of the tilt angle θ is between 7° and 10°, that is, when the tilt angle θ is between 7° and 10°, the spurious mode can be completely suppressed.

[0103] In some embodiments, Fig. 22 As shown, the opening 4 includes a first sub-opening 41 and a second sub-opening 42 that are connected. The first sub-opening 41 is at least located in the gap area 20, that is, the first sub-opening 41 can be located only in the gap area 20, or in the gap area 20 and the edge area 40. The top of the first sub-opening 41 (the end of the first sub-opening 41 away from the substrate 1) can cover the entire gap area 20. The first sub-opening 41 extends from the side of the piezoelectric layer 2 away from the substrate 1 along the second direction Y into the piezoelectric layer 2, or the first sub-opening 41 penetrates the piezoelectric layer 2 along the second direction Y. The interface between the piezoelectric layer 2 and the first sub-opening 41 tends to be inclined toward the electrode finger area 10.

[0104] The second sub-opening 42 is located on the side of the piezoelectric layer 2 close to the first sub-opening 41. The second sub-opening 42 can be located at any position on the side of the piezoelectric layer 2 close to the first sub-opening 41, such as the second sub-opening 42 can be located at the bottom of the first sub-opening 41, and the second sub-opening 42 can also be located at the top of the first sub-opening 41, which is not specifically limited here. The second sub-opening 42 can be located only in the gap area 20, or only in the edge area 40, or in the gap area 20 and the edge area 40. The side wall of the piezoelectric layer 2 close to the second sub-opening 42 can be perpendicular to the lower surface of the piezoelectric layer 2 (that is, the surface of the piezoelectric layer 2 close to the substrate 1), or can be inclined in the direction of the electrode finger area 10. Among them, the height of the second sub-opening 42 along the second direction Y is much smaller than the height of the first sub-opening 41 along the second direction Y.

[0105] When the resonator further includes the first dielectric layer 5, the first dielectric layer 5 fills the first sub-opening 41 and the second sub-opening 42. When the first dielectric layer 5 is a stacked structure, the first sub-opening 41 and the second sub-opening 42 can be filled with the same film layer or different film layers.

[0106] For example, the first sub-opening 41 penetrates the piezoelectric layer 2 along the second direction Y, and the second sub-opening 42 is located on a side of the piezoelectric layer 2 close to the first sub-opening 41 and is disposed close to the substrate 1. The first dielectric layer 5 includes a first film layer 51 and a second film layer 52, the second film layer 52 fills the second sub-opening 42 and is located at the bottom of the first sub-opening 41, and the first film layer 51 fills the first sub-opening 41.

[0107] In some embodiments, Fig.23 As shown, the electrode finger can also extend to a portion of the interface between the piezoelectric layer 2 and the opening 4. When the opening 4 is located in the first gap sub-region 20a, the second electrode finger 32 extends along the first direction X in the electrode finger region 10 and the second gap sub-region 20b, and extends to a portion of the interface between the piezoelectric layer 2 and the opening 4 in the first gap sub-region 20a. When the opening 4 is located in the second gap sub-region 20b, the first electrode finger 31 extends along the first direction X in the electrode finger region 10 and the first gap sub-region 20a, and extends to a portion of the interface between the piezoelectric layer 2 and the opening 4 in the second gap sub-region 20b.

[0108] When the first dielectric layer 5 is filled in the opening 4 , the electrode fingers extend to a portion of the interface between the piezoelectric layer 2 and the first dielectric layer 5 , that is, the extended portion of the electrode fingers is located between the piezoelectric layer 2 and the first dielectric layer 5 .

[0109] In some embodiments, at least part of the interface between the piezoelectric layer 2 and the opening 4 includes at least one of a plane, a curved surface, and a folded line surface. In the case where the first dielectric layer 5 is filled in the opening 4, at least part of the interface between the first dielectric layer 5 and the piezoelectric layer 2 may include at least one of a plane, a curved surface, and a folded line surface. The folded line surface may include a step surface.

[0110] like Figure 1 and Figure 3 As shown, all interfaces between the piezoelectric layer 2 and the opening 4 are inclined toward the electrode finger region 10, and the interface between the piezoelectric layer 2 and the opening 4 is an inclined plane. When the first dielectric layer 5 is filled in the opening 4, the interface between the piezoelectric layer 2 and the first dielectric layer 5 is inclined toward the electrode finger region 10, and the interface is an inclined plane.

[0111] like Fig.24 and Fig.25 As shown, all interfaces between the piezoelectric layer 2 and the opening 4 are inclined toward the electrode finger region 10, and the interface between the piezoelectric layer 2 and the opening 4 is an inclined folded surface, such as an inclined step surface. Fig.24 Each step in the step surface consists of a vertical surface (the vertical surface is perpendicular to the first direction X) and a horizontal surface (the horizontal surface is perpendicular to the second direction Y), and the size of each step in the step surface is smaller than the wavelength. Fig.25 Each step in the step surface is composed of an inclined surface (the inclined surface is inclined toward the electrode finger area 10) and a horizontal surface. When the opening 4 is filled with the first dielectric layer 5, the interface between the piezoelectric layer 2 and the first dielectric layer 5 tends to be inclined toward the electrode finger area 10, and the interface is a step surface with an inclined trend.

[0112] like Fig.26 As shown, the entire interface between the piezoelectric layer 2 and the opening 4 is inclined toward the electrode finger region 10, and the interface between the piezoelectric layer 2 and the opening 4 is an inclined curved surface, which may be recessed toward the electrode finger region 10. When the opening 4 is filled with the first dielectric layer 5, the interface between the piezoelectric layer 2 and the first dielectric layer 5 is inclined toward the electrode finger region 10, and the interface is an inclined curved surface.

[0113] like Fig. 22 As shown, part of the interface between the piezoelectric layer 2 and the opening 4 is inclined toward the electrode finger region 10, and the part of the interface between the piezoelectric layer 2 and the opening 4 is an inclined plane, and the remaining interface between the piezoelectric layer 2 and the opening 4 can be a vertical plane. In the case where the opening 4 is filled with the first dielectric layer 5, part of the interface between the piezoelectric layer 2 and the first dielectric layer 5 is inclined toward the electrode finger region 10, and the part of the interface is an inclined plane, and the remaining interface can be a vertical plane.

[0114] like Fig. 27 As shown, part of the interface between the piezoelectric layer 2 and the opening 4 is inclined toward the electrode finger region 10, and the part of the interface between the piezoelectric layer 2 and the opening 4 is an inclined fold line surface, such as an inclined step surface, and the remaining interface between the piezoelectric layer 2 and the opening 4 can be a vertical plane. In the case where the opening 4 is filled with the first dielectric layer 5, part of the interface between the piezoelectric layer 2 and the first dielectric layer 5 is inclined toward the electrode finger region 10, and the part of the interface is an inclined fold line surface, and the remaining interface can be a vertical plane.

[0115] In some embodiments, Figure 1 As shown, the resonator further includes a second dielectric layer 6. The second dielectric layer 6 is located in the busbar region 30, and the second dielectric layer 6 is located between the base 1 and the electrode layer 3. In the case where the base 1 includes the substrate 11 and the support layer 12, the second dielectric layer 6 is located between the support layer 12 and the electrode layer 3.

[0116] Combination Figure 2 As shown, the second dielectric layer 6 is located in the first busbar sub-area 30 a and the second busbar sub-area 30 b , and the first busbar 33 and the second busbar 34 are both located on the side of the second dielectric layer 6 facing away from the substrate 1 .

[0117] The second dielectric layer 6 may include SiO 2 、Si 3 N 4 、Al 2 O 3 、 2 O 5 , ALN, SiC, etc. The material of the second dielectric layer 6 and the first dielectric layer 5 can be the same or different.

[0118] According to the resonator provided in the embodiment of the present application, an opening is provided at the edge of the piezoelectric layer so that the opening is at least located in the gap area, and at least a portion of the interface between the piezoelectric layer and the opening is inclined toward the electrode finger area, so as to reflect the stray mode transmitted to the gap area to the substrate and avoid the stray mode from being reflected back to the electrode finger area, thereby suppressing the stray mode while ensuring the propagation characteristics of the main mode and improving the performance of the resonator.

[0119] Correspondingly, an embodiment of the present application further provides a filter, including the resonator in the above embodiment, which will not be described in detail here.

[0120] According to the filter provided in the embodiment of the present application, an opening is set at the edge of the piezoelectric layer so that the opening is at least located in the gap area, and at least a portion of the interface between the piezoelectric layer and the opening is inclined toward the electrode finger area, so as to reflect the stray mode transmitted to the gap area to the substrate and avoid the stray mode from being reflected back to the electrode finger area. This can suppress the stray mode while ensuring the propagation characteristics of the main mode, thereby improving the performance of the resonator and thus improving the performance of the filter.

[0121] Correspondingly, an embodiment of the present application further provides an electronic device, including the filter in the above embodiment, which will not be described in detail here.

[0122] According to the electronic device provided in the embodiment of the present application, an opening is provided at the edge of the piezoelectric layer so that the opening is at least located in the gap area, and at least a portion of the interface between the piezoelectric layer and the opening is inclined toward the electrode finger area, so as to reflect the stray mode transmitted to the gap area to the substrate and avoid the stray mode from being reflected back to the electrode finger area, thereby suppressing the stray mode while ensuring the propagation characteristics of the main mode, improving the performance of the resonator, and further improving the performance of the electronic device.

[0123] The terms "first", "second", etc. in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same type, and the number of objects is not limited. For example, the first object can be one or more.

[0124] In the description of the present application, “plurality” means two or more.

[0125] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0126] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A resonator, characterized in that: include: A substrate, comprising an electrode finger region, a bus bar region located at two opposite sides of the electrode finger region along a first direction, and a gap region located between the electrode finger region and the bus bar region; a piezoelectric layer located in the electrode finger region and the gap region, and located on one side of the substrate along the second direction; an edge of the piezoelectric layer has an opening, the opening is at least located in the gap region, and at least part of the interface between the piezoelectric layer and the opening is inclined toward the direction of the electrode finger region; the second direction is the thickness direction of the substrate, and the first direction is perpendicular to the second direction; The electrode layer is located in the electrode finger region, the gap region and the busbar region, and is located on a side of the piezoelectric layer away from the substrate.

2. The resonator according to claim 1, characterized in that The opening extends from a side of the piezoelectric layer facing away from the substrate into the piezoelectric layer along the second direction, or the opening penetrates the piezoelectric layer along the second direction.

3. The resonator according to claim 1, characterized in that An orthographic projection of a top of the opening on the substrate coincides with the gap region.

4. The resonator according to claim 1, characterized in that The electrode finger region includes an edge region close to the gap region; The openings are located in the gap region and the edge region.

5. The resonator according to claim 1, characterized in that The opening comprises a first sub-opening and a second sub-opening which are connected; The first sub-opening is at least located in the gap region, the interface between the piezoelectric layer and the first sub-opening tends to be inclined toward the electrode finger region, and the second sub-opening is located on a side of the piezoelectric layer close to the first sub-opening.

6. The resonator according to claim 5, characterized in that The second sub-opening is located at the bottom of the first sub-opening.

7. The resonator according to claim 1, characterized in that The electrode layer includes electrode fingers located in the electrode finger region and extending along the first direction; The electrode fingers also extend to a portion of the interface between the piezoelectric layer and the opening.

8. The resonator according to claim 1, characterized in that The resonator also includes a first dielectric layer; The first dielectric layer is filled in the opening.

9. The resonator according to claim 8, characterized in that The first dielectric layer is a single-layer structure or a stacked-layer structure.

10. The resonator according to claim 9, characterized in that At least part of the interface between the piezoelectric layer and the opening is covered by the same membrane layer.

11. The resonator according to claim 1, characterized in that At least a portion of the interface between the piezoelectric layer and the opening includes at least one of a plane, a curved surface, and a fold line surface, and the fold line surface includes a step surface.

12. The resonator according to claim 1, characterized in that The piezoelectric layer includes lithium tantalate, and the at least partial interface between the piezoelectric layer and the opening is inclined at an angle between 5° and 30°.

13. The resonator according to any one of claims 1 to 12, characterized in that: The resonator further comprises a second dielectric layer; The second dielectric layer is located in the busbar region and between the substrate and the electrode layer.

14. A filter, characterized in that: Comprising a resonator as claimed in any one of claims 1 to 13.

15. An electronic device, characterized in that: Comprising a filter as claimed in claim 14.

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