CN119582797A - Resonators, filters and electronic devices - Google Patents

Abstract

The present application discloses a resonator, a filter and an electronic device, belonging to the field of semiconductor technology. The resonator includes: a substrate, including an electrode finger area, a busbar area located on opposite sides of the electrode finger area along a first direction, and a gap area between the electrode finger area and the busbar area; a piezoelectric layer located in the electrode finger area and the gap area, and located on one side of the substrate along a second direction; the edge of the piezoelectric layer has an opening, 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 direction of the electrode finger area; the first direction is perpendicular to the second direction; an electrode layer is located in the electrode finger area, the gap area and the busbar area, and is located on the side of the piezoelectric layer away from the substrate. The present application can suppress spurious modes and improve the performance of the resonator.

Description

Resonator, filter and electronic device

Technical Field

The present application relates to the field of semiconductor technologies, and in particular, to a resonator, a filter, and an electronic device.

Background

The resonator is widely applied to mobile communication equipment and has the advantages of low insertion loss, wide bandwidth, small volume, low cost, mass production and the like. However, the resonator is excited in the main mode and also produces unnecessary spurious modes (such as spurious generated by transverse modes perpendicular to the main mode), which affect the performance of the resonator.

Disclosure of Invention

The present application aims to solve at least one of the technical problems existing in the prior art. Therefore, the application provides a resonator, a filter and an electronic device, which can inhibit stray modes and improve the performance of the resonator.

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

the substrate comprises an electrode finger area, bus areas positioned on two opposite sides of the electrode finger area along a first direction, and a gap area positioned between the electrode finger area and the bus areas;

The piezoelectric layer is positioned in the electrode finger area and the gap area and is positioned at one side of the substrate along the second direction; the edge of the piezoelectric layer is provided with an opening, the opening is at least positioned in the gap area, and at least part of the interface between the piezoelectric layer and the opening is inclined towards the direction of the electrode finger area;

and the electrode layer is positioned at the electrode finger area, the gap area and the bus area and is positioned at one side of the piezoelectric layer, which is away from the substrate.

According to the resonator provided by the application, the opening is arranged at the edge of the piezoelectric layer, so that the opening is at least positioned in the gap region, and at least part of the interface between the piezoelectric layer and the opening is inclined towards the direction of the electrode finger region, so that the stray mode transmitted to the gap region is reflected to the substrate, and the stray mode is prevented from being reflected back to the electrode finger region, thereby inhibiting the stray mode and improving the performance of the resonator while ensuring the propagation characteristic of the main mode.

According to an embodiment of the application, the opening extends into the piezoelectric layer from a side of the piezoelectric layer facing away from the substrate in the second direction or the opening extends through the piezoelectric layer in the second direction.

According to one embodiment of the application, the orthographic projection of the top of the opening onto the substrate coincides with the gap region.

According to one embodiment of the application, the electrode finger region includes an edge region adjacent to the gap region;

The opening is located in the gap region and the edge region.

According to one embodiment of the application, the opening comprises a first sub-opening and a second sub-opening in communication;

the first sub-opening is at least located in the gap area, the interface between the piezoelectric layer and the first sub-opening is inclined towards the direction of the electrode finger area, and the second sub-opening is located on one side, close to the first sub-opening, of the piezoelectric layer.

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

According to one embodiment of the application, the electrode layer comprises electrode fingers located in the electrode finger regions and extending in the first direction;

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

According to one embodiment of the application, the resonator further comprises a first dielectric layer;

the first dielectric layer fills in the opening.

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

According to one embodiment of the application, said at least part of the interface between said piezoelectric layer and said opening is covered by the same film layer.

According to one embodiment of the application, the at least partial interface between the piezoelectric layer and the opening comprises at least one of a plane, a curved surface and a fold line surface, the fold line surface comprising a stepped surface.

According to one embodiment of the application, the piezoelectric layer comprises lithium tantalate, and the at least partial interface between the piezoelectric layer and the opening is inclined at an angle between 5 ° and 30 °.

According to one embodiment of the application, the resonator further comprises a second dielectric layer;

The second dielectric layer is located in the bus bar area and between the substrate and the electrode layer.

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

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

The above technical solutions in the embodiments of the present application have at least one of the following technical effects:

Through setting up the opening at the edge of piezoelectricity layer, make the opening be located the clearance district at least, and at least partial interface between piezoelectricity layer and the opening is the trend to the direction slope of electrode finger district to reflect to the basement with the spurious mode that transmits to the clearance district, avoid spurious mode reflection back electrode finger district, thereby restrain spurious mode when guaranteeing main mode propagation characteristic, improve the performance of resonator.

Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application.

Drawings

The foregoing and/or additional aspects and advantages of the application will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic diagram of a resonator according to an embodiment of the present application;

FIG. 2 is a top view of a resonator provided by an embodiment of the present application;

FIG. 3 is a schematic diagram of a resonator according to an embodiment of the application;

FIG. 4 is a schematic diagram of a resonator according to an embodiment of the present application;

FIG. 5 is a schematic diagram of a resonator according to a second embodiment of the present application;

FIG. 6 is a graph showing frequency versus conductance for a resonator according to an embodiment of the present application at different tilt angles;

FIG. 7 is a graph of frequency versus admittance for a resonator according to an embodiment of the present application;

FIG. 8 is a second graph of frequency versus admittance for a resonator according to an embodiment of the present application;

FIG. 9 is a graph of frequency versus conductance for resonators provided by embodiments of the present application at different gap region widths;

FIG. 10 is a graph of frequency versus conductance for resonators provided by embodiments of the present application at different piezoelectric layer thicknesses;

FIG. 11 is a graph of frequency versus admittance for resonators provided by embodiments of the present application at different piezoelectric layer thicknesses;

FIG. 12 is a graph of frequency versus conductance for a resonator according to an embodiment of the present application at different apertures;

FIG. 13 is a graph of frequency versus mechanical Q for a resonator according to an embodiment of the present application at different tilt angles;

FIG. 14 is a graph of tilt angle versus wave velocity and k2 for a resonator according to an embodiment of the present application;

FIG. 15 is a third schematic diagram of a resonator according to an embodiment of the present application;

FIG. 16 is a schematic diagram of a resonator according to an embodiment of the present application;

FIG. 17 is a schematic diagram of a resonator according to an embodiment of the present application;

FIG. 18 is a graph of frequency versus conductance for a resonator according to an embodiment of the present application at different L1;

FIG. 19 is a schematic diagram of a resonator according to an embodiment of the present application;

FIG. 20 is a graph of frequency versus conductance for a resonator according to an embodiment of the present application at different L2;

FIG. 21 is a graph showing a second relationship between frequency and conductance of a resonator according to an embodiment of the present application at different tilt angles;

FIG. 22 is a schematic diagram of a resonator according to an embodiment of the present application;

FIG. 23 is a schematic diagram of a resonator according to an embodiment of the present application;

FIG. 24 is a diagram illustrating a resonator according to an embodiment of the present application;

FIG. 25 is a schematic diagram of a resonator according to an embodiment of the present application;

FIG. 26 is a schematic diagram of a resonator according to an embodiment of the present application;

fig. 27 is a schematic diagram of a resonator according to an embodiment of the present application.

Detailed Description

Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the application.

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

Fig. 1 is a schematic structural diagram of a resonator according to 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-mount (SMR) resonator, a transverse excited bulk acoustic wave resonator (XBAR), a shear wave resonator (YBAR), a POI (piezoelectric-on-insulator film) resonator, or the like.

As shown in fig. 1, 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 sequentially arranged along a second direction Y, which is a thickness direction of the substrate 1.

The substrate 1 includes a device region for disposing a device (such as a surface acoustic wave device or a bulk acoustic wave device). The device region includes an electrode finger region 10, bus bar regions 30 located on opposite sides of the electrode finger region 10 in the first direction X, and a gap region 20 located between the electrode finger region 10 and the bus bar regions 30. The first direction X is perpendicular to the second direction Y.

As shown in connection with fig. 2, the busbar zone 30 may comprise a first busbar zone 30a and a second busbar zone 30b, the first busbar zone 30a and the second busbar zone 30b being located on opposite sides of the electrode finger zone 10 in the first direction X, respectively. The gap region 20 may include a first gap sub-region 20a and a second gap sub-region 20b, the first gap sub-region 20a being located between the electrode finger region 10 and the first bus-bar sub-region 30a, the second gap sub-region 20b being located between the electrode finger region 10 and the second bus-bar sub-region 30 b.

In some embodiments, as shown in fig. 1, 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 in the second direction Y. Wherein the substrate 1 may comprise a silicon substrate or the like. The support layer 12 may comprise silicon oxide or the like, such as silicon dioxide. The substrate 1 may further comprise other film layers according to practical needs, and is not particularly limited herein.

The piezoelectric layer 2 is located on one side of the substrate 1 in the second direction Y, and the piezoelectric layer 2 is located in the electrode finger region 10 and the gap region 20. In case the base 1 comprises a substrate 11 and a support layer 12, the piezoelectric layer 2 is located on the side of the support layer 12 facing away from the substrate 11. Among them, the piezoelectric layer 2 may include lithium tantalate (LiTaO ₃) or the like.

The piezoelectric layer 2 has an opening 4, the opening 4 being located at the edge of the piezoelectric layer 2, and the opening 4 being located at least in the gap region 20. The openings 4 may be located only in the gap region 20 (the openings 4 may be located in part of the gap region 20 or in all of the 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, as shown in fig. 2, the opening 4 may be located in the first gap region 20a, may be located in the second gap region 20b, or may be located in both the first gap region 20a and the second gap region 20b. In case the openings 4 are located in the first and second gap sub-regions 20a, 20b, the shape and size of the openings 4 of the first gap sub-region 20a may be the same or different from the openings 4 of the second gap sub-region 20b.

At least part of the boundary between the piezoelectric layer 2 and the opening 4 has a tendency to tilt in the direction of the electrode finger region 20. At least part of the boundary surface between the piezoelectric layer 2 and the opening 4 of the first gap sub-region 20a is inclined in the direction of the electrode finger region 20 in the case where the opening 4 is located in the first gap sub-region 20a, and at least part of the boundary surface between the piezoelectric layer 2 and the opening 4 of the second gap sub-region 20b is inclined in the direction of the electrode finger region 20 in the case where the opening 4 is located in the second gap sub-region 20 b.

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, i.e. the electrode layer 3 is located in the device region.

In some embodiments, as shown in connection with fig. 2, the electrode layer 3 includes a plurality of electrode fingers, a first bus bar 33, and a second bus bar 34. The first bus bar 33 and the second bus bar 34 are both located in the bus bar area 30 and extend along a third direction Z, which is perpendicular to the first direction X and the second direction Y, respectively. The first busbar 33 is located in the first busbar zone 30a and the second busbar 34 is located in the second busbar zone 30b. The plurality of electrode fingers includes first electrode fingers 31 and second electrode fingers 32 alternately and alternately arranged in the third direction Z. The first electrode finger 31 and the second electrode finger 32 are both located in the electrode finger region 10 and extend in the first direction X. The first electrode finger 31 extends from the electrode finger region 10 in the first direction X to the first gap sub-region 20a and is connected to the first busbar 33, i.e. the first electrode finger 31 is located in the electrode finger region 10 and the first gap sub-region 20a. The second electrode finger 32 extends from the electrode finger region 10 in the first direction X to the second gap sub-region 20b and is connected to the second busbar 34, i.e. the second electrode finger 32 is located in the electrode finger region 10 and the second gap sub-region 20b.

Wherein the number of the first electrode fingers 31 and the second electrode fingers 32 may be the same. The dimensions (including length, width, etc.) of the first electrode finger 31 and the second electrode finger 32 may be the same. The materials of the first electrode finger 31 and the second electrode finger 32 may each include a metal material such as copper, aluminum, or the like. The first bus bar 33 and the second bus bar 34 may serve as connection lines connecting adjacent resonators or connection lines connecting package sides. The materials of the first bus bar 33 and the second bus bar 34 may each include a metal material such as copper, aluminum, or the like.

In this embodiment, the size of the resonator or the structure of the electrode layer does not need to be changed, the opening 4 is only arranged at the edge of the piezoelectric layer 2, so that the opening 4 is at least located in the gap region 20, at least part of the boundary surface between the piezoelectric layer 2 and the opening 4 is inclined towards the direction of the electrode finger region 10, and the stray mode transmitted to the gap region 20 can be reflected to the substrate 1, so that the transmission characteristic of the main mode is ensured, meanwhile, the stray mode is restrained, the Q value of the resonator is improved, the acoustic energy is better restrained, the scattering loss is reduced, and the performance of the resonator is improved. Moreover, the embodiment can be used in combination with other spurious suppression methods, such as piston mode IDT and slowness curve optimization slowness curve optimization, to further improve spurious suppression.

In some embodiments, as shown in fig. 2 and 3, the resonator further comprises a first dielectric layer 5, the first dielectric layer 5 is filled in the opening 4, i.e. the first dielectric layer 5 is located at the side of the piezoelectric layer 2, and the first dielectric layer 5 is located at least in the gap region 20. The at least partial interface between the piezoelectric layer 2 and the opening 4 comprises a partial interface between the piezoelectric layer 2 and the first dielectric layer 5, i.e. at least a partial interface between the piezoelectric layer 2 and the first dielectric layer 5 has a tendency to tilt in the direction of the electrode finger 10. The first dielectric layer 5 may include one or more combinations of SiO ₂、Si₃N₄、Al₂O₃、Ta₂O₅, ALN, siC, etc. The first dielectric layer 5 may also include a piezoelectric layer that is different from the material of the piezoelectric layer 2, or have a doped piezoelectric layer, so long as the first dielectric layer 5 and the piezoelectric layer 2 are guaranteed to be two different media, which is not specifically limited herein.

In this embodiment, the first dielectric layer 5 is disposed on the side surface of the piezoelectric layer 2, the first dielectric layer 5 is at least located in the gap region 20, and at least part of the interface between the piezoelectric layer 2 and the first dielectric layer 5 is inclined towards the direction of the electrode finger region 10, so that the stray mode transmitted to the gap region 20 can be reflected to the substrate 1, thereby suppressing the stray mode and improving the performance of the resonator while ensuring the transmission characteristic of the main mode.

It should be noted that by adjusting the inclination angle of the at least part of the interface between the piezoelectric layer 2 and the opening 4, all spurious modes can be attenuated and leaked to the substrate 1, and the spurious modes are prevented from returning to the piezoelectric layer 2, so that the spurious modes can be effectively suppressed in a wide frequency range.

As shown in fig. 4, the transverse mode TM is transmitted to the interface between the piezoelectric layer 2 and the first dielectric layer 5, and simultaneously a transmitted wave S1 and a reflected wave S2 are generated. In general, the propagation directions of the transmitted wave S1 and the reflected wave S2 are different, and due to multiple reflection, a part of the wave returns to the piezoelectric layer 2 as a spurious mode, and the spurious mode cannot be completely suppressed. By adjusting the tilt angle θ of the at least part of the interface between the piezoelectric layer 2 and the first dielectric layer 5, as shown in fig. 5, total internal reflection occurs, and both the transmitted wave S1 and the reflected wave S2 propagate to the substrate 1, avoiding the spurious modes returning to the piezoelectric layer 2, so as to completely suppress the spurious modes over a wide frequency range.

The optimum 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 from parameters such as the wave velocities 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 have a strong dependence on direction and are 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 a three-dimensional finite element model (3D FEM model) of the resonator, to obtain an optimal value of the tilt angle θ.

For example, the substrate 11 comprises silicon, the support layer 12 comprises silicon dioxide, the piezoelectric layer 2 comprises Y-cut LT material, the electrode layer comprises aluminum, the wavelength λ is 1.9 μm, the duty factor DF of the electrode fingers (ratio of electrode finger width to electrode finger pitch) is 0.5, and the width of the gap region (width G of the first gap sub-region 20a and width G of the second gap sub-region 20 b) is fixed to 2λ. The tilt angle θ was adjusted between 0 and 90 °, and the conductivity characteristics of the resonators were detected, respectively, as shown in fig. 6. It can be seen that the optimum value of the tilt angle θ lies between 8 ° and 10 °, i.e. the tilt angle θ lies between 8 ° and 10 °, the resonator has a better spurious suppression effect. Fig. 7 is a schematic diagram of the frequency and admittance of the resonator when the inclination angle θ is 3 ° and fig. 8 is a schematic diagram of the frequency and admittance of the resonator when the inclination angle θ is 10 °, as shown in conjunction with fig. 7 and 8. It can be seen that the resonator has a better spurious suppression effect at an inclination angle θ of 10 °.

The structural parameters and the film materials in the resonator change, and the optimal value of the inclination angle theta changes. For any resonator, the optimal value of the tilt angle θ lies between 5 ° and 15 ° or between 2 ° and 45 °.

In addition, the inclination angle θ was fixed at 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 20 b) was adjusted between 0.5λ and 4.0λ, and the conductive characteristics of the resonators were detected, respectively, as shown in fig. 9. It can be seen that the width of the gap region has no significant effect on the suppression of spurious modes.

The tilt angle θ was fixed to 10 °, and the widths of the gap regions (the width G of the first gap sub-region 20a and the width G of the second gap sub-region 20 b) were fixed to 2λ, and the thickness H of the piezoelectric layer 2 was adjusted between 300nm and 1000nm, and the conductivity characteristics of the resonators were detected, respectively, as shown in fig. 10. It can be seen that the thickness H of the piezoelectric layer 2 has no significant effect on the suppression of spurious modes. Further, as shown in fig. 11, fig. 11 is a schematic diagram showing the relationship between the frequency and admittance of the resonator when the tilt angle θ is fixed to 10 °, and the thicknesses H of the piezoelectric layer 2 are 0.3 μm, 0.6 μm, and 0.9 μm, respectively. It can be seen that at an inclination angle θ of 10 °, good spurious suppression can be achieved for the resonator regardless of the thickness adjustment of the piezoelectric layer 2.

While the resonator aperture has a large influence on the spectrum and intensity of the transverse mode. In general, the higher order mode intensity of a resonator with a relatively small aperture (e.g., less than 20λ) decreases and the lower order mode intensity increases. When Gao Zhenfu spurious occurs near the resonant frequency, it is difficult to suppress spurious modes well. Thus, the present embodiment evaluates the conductivity characteristics of resonators of different apertures. The tilt angle θ was 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 20 b) was fixed to 2λ, the resonator aperture D was adjusted between 5λ and 60deg.λ, and the conductivity characteristics of the resonators were detected, respectively, as shown in fig. 12. It can be seen that spurious modes can be well suppressed when the resonator aperture D is smaller than 10λ.

Fig. 13 is a schematic diagram showing the relationship between the frequency of the resonator and the mechanical Q value of the piezoelectric layer when the inclination angle θ is 3 °,10 °, and 80 °, respectively. It can be seen that at tilt angles θ of 3 ° and 10 °, the influence on the main mode energy constraint and Q value is small. When the inclination angle θ is greater than 45 °, the Q value may be lowered below the resonance frequency due to leakage of the acoustic wave to the first dielectric layer. Therefore, by adjusting the tilt angle θ, it is possible to ensure that the influence on the main mode energy constraint and the Q value is small or no.

As shown in fig. 14, fig. 14 is a schematic diagram showing the relationship between the inclination angle θ and the wave velocity and the electromechanical coupling coefficient k 2. It can be seen that the influence of the wave velocity and k2 on the tilt angle θ is small. In the larger range of the inclination angle theta, the wave velocity is kept almost unchanged, and k2 is slightly reduced. By adjusting the inclination angle θ, the attenuation of k2 can be ensured to be less than 0.2%, which is equivalent to the normal deviation of the parameters.

In some embodiments, the piezoelectric layer 2 comprises Lithium Tantalate (LT), and the angle of inclination of the at least part of the interface between the piezoelectric layer 2 and the opening 4 is between 5 ° and 30 °, i.e. 5 ° and θ and 30 °.

In some embodiments, as shown in fig. 3 and 15, the first dielectric layer 5 may be a single layer structure. As shown in fig. 16, the first dielectric layer 5 may have a stacked structure. In the case where the first dielectric layer 5 is a stacked structure, the first dielectric layer 5 includes a plurality of film layers, and the number of film layers is not particularly limited. The materials and thicknesses of the plurality of film layers may be the same or different. The lamination direction of the plurality of film layers may be parallel to the first direction X or may intersect the first direction X, and is not particularly limited herein.

In some embodiments, where the first dielectric layer 5 is a laminated structure, the at least part of the interface between the piezoelectric layer 2 and the opening 2 is covered by the same film layer.

As shown in fig. 16, the first dielectric layer 5 may include a first film layer 51 and a second film layer 52. The second film 52 is located in the opening 2 and covers the side wall of the piezoelectric layer 2 near the opening 2, and the first film 52 fills the opening 2.

In this embodiment, the first dielectric layer 5 has a laminated structure, so that the acoustic characteristics of the gap region can be adjusted according to different film layers, and the suppression effect of the stray mode can be further improved.

In some embodiments, as shown in fig. 1 and 3, the opening 4 may extend into the piezoelectric layer 2 in the second direction Y from a side of the piezoelectric layer 2 facing away from the substrate 1, i.e., the opening 4 does not extend through the piezoelectric layer 2 in the second direction Y, may cause a portion of the surface of the piezoelectric layer 2 on opposite sides in the first direction X to have a tendency to tilt toward the electrode finger region 10, reflecting the spurious modes transmitted to the gap region 20 to the substrate to suppress spurious.

As shown in fig. 15 and 16, the opening 4 may also penetrate the piezoelectric layer 2 along the second direction Y, and may make at least part of the surfaces (such as all the surfaces) of the opposite sides of the piezoelectric layer 2 along the first direction X tilt toward the direction of the electrode finger region 10, so as to reflect more spurious modes transmitted to the gap region 20 to the substrate 1, so as to suppress more spurious.

In case the openings 4 are located in the first and second gap sub-regions 20a, 20b, the openings 4 of the first gap sub-region 20a may extend into the piezoelectric layer 2 or through the piezoelectric layer 2 in the second direction Y from the side of the piezoelectric layer 2 facing away from the substrate 1, and the openings 4 of the second gap sub-region 20b may extend into the piezoelectric layer 2 or through the piezoelectric layer 2 in the second direction Y from the side of the piezoelectric layer 2 facing away from the substrate 1. The extension of the opening 4 of the first gap sub-region 20a and the extension of the opening 4 of the second gap sub-region 20b in the second direction Y may be the same or different.

In case the opening 4 is filled with the first dielectric layer 5, the first dielectric layer 5 extends into the piezoelectric layer 2 in the second direction Y from the side of the piezoelectric layer 2 facing away from the substrate 1, or the first dielectric layer 5 penetrates the piezoelectric layer 2 in the second direction Y.

In some embodiments, as shown in fig. 1, 3, 15 and 16, the front projection of the top of the opening 4 (the end of the opening 4 facing away from the substrate 1) onto the substrate 1 coincides with the gap region 20, i.e. the front projection of the top of the opening 4 onto the substrate 1 completely covers the gap region 20. In case the opening 4 is filled with the first dielectric layer 5, the front projection of the upper surface of the first dielectric layer 5 (the surface of the side of the first dielectric layer 5 facing away from the substrate 1) onto the substrate 1 completely covers the gap region 20.

In some embodiments, as shown in fig. 17, an orthographic projection of the top of the opening 4 onto the substrate 1 covers a portion of the gap region 20. In case the opening 4 is filled with the first dielectric layer 5, the orthographic projection of the upper surface of the first dielectric layer 5 on the substrate 1 covers part of the gap region 20.

To ensure that the tilt angle θ is at an optimal value, it is possible to cover part of the gap region 20 by shortening the length of the electrode finger in the first direction X and increasing the width of the gap region 20 in the first direction X such that the orthographic projection of the top of the opening 4 onto the substrate 1. The upper surface of the first dielectric layer 5 has a distance L1 from the electrode finger region 10, i.e. the length of the electrode finger shortened along the first direction X is L1.

As shown in fig. 18, the tilt angle θ was fixed to 10 °, L1 was adjusted between 0 λ and 3λ, and the conductivity characteristics of the resonators were detected, respectively. It can be seen that when L1 is greater than 0, the spurious suppression effect of the resonator is reduced, but compared with the related art, the embodiment still has a certain suppression effect on the spurious mode.

In some embodiments, as shown in fig. 19, electrode finger regions 10 include edge regions 40 disposed adjacent to gap regions 20, with openings 4 located in gap regions 20 and edge regions 40. The orthographic projection of the top of the opening 4 onto the substrate 1 may cover the entire gap region 20 and at least part of the edge region 40. In case the opening 4 is filled with the first dielectric layer 5, the first dielectric layer 5 may be located in the gap region 20 and the edge region 40. The front projection of the upper surface of the first dielectric layer 5 onto the substrate 1 may cover the entire gap region 20 and at least part of the edge region 40.

The electrode finger region 10 further comprises a body region 50, and edge regions 40 are located on opposite sides of the body region 50 in the first direction X, i.e. the edge regions 40 are located between the body region 50 and the first gap sub-region 20a and between the body region 50 and the second gap sub-region 20 b. The opening 4 may be located in the edge region 40 and the gap region 20 on either side of the body region 50, or may be located in the edge region 40 and the gap region 20 on both sides of the body region 50.

To ensure that the tilt angle θ is at an optimal value, it is possible to extend the length of the electrode finger in the first direction X and to reduce the width of the gap region 20 in the first direction X such that the orthographic projection of the top of the opening 4 onto the substrate 1 covers all the gap region 20 and at least part of the edge region 40. The upper surface of the first dielectric layer 5 has a length L2 in the edge region 40, i.e. the electrode finger extends over a length L2.

As shown in fig. 20, the tilt angle θ was fixed to 10 °, L2 was adjusted between 0 λ and 2λ, and the conductivity characteristics of the resonators were detected, respectively. It can be seen that the spurious suppression effect of the resonator is slightly reduced. At L2 less than or equal to 0.25 λ, the spurious suppression effect of the resonator is negligible, i.e., the resonator has good spurious suppression effect.

By adjusting the inclination angle θ, complete suppression of the spurious mode can be achieved. As shown in fig. 21, L2 is fixed to 0.5λ, the inclination angle θ is adjusted in the range of 5 ° to 15 °, and the conductivity characteristics of the resonators are detected, respectively. It can be seen that the stray mode can be completely suppressed when the optimum value of the inclination angle θ is between 7 ° and 10 °, i.e., the inclination angle θ is between 7 ° and 10 °.

In some embodiments, as shown in fig. 22, the opening 4 includes a first sub-opening 41 and a second sub-opening 42 that are in communication. The first sub-opening 41 is located at least in the gap region 20, i.e. the first sub-opening 41 may be located only in the gap region 20 or may be located in the gap region 20 and the edge region 40. The top of the first sub-opening 41 (the end of the first sub-opening 41 facing away from the substrate 1) may cover the entire gap region 20. The first sub-opening 41 extends into the piezoelectric layer 2 in the second direction Y from the side of the piezoelectric layer 2 facing away from the substrate 1, or the first sub-opening 41 penetrates the piezoelectric layer 2 in the second direction Y. The interface between the piezoelectric layer 2 and the first sub-opening 41 has a tendency to tilt in the direction of the electrode finger 10.

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 may be located at any position on the piezoelectric layer 2 near the side of the first sub-opening 41, for example, the second sub-opening 42 may be located at the bottom of the first sub-opening 41, and the second sub-opening 42 may also be located at the top of the first sub-opening 41, which is not particularly limited herein. The second sub-opening 42 may be located only in the gap region 20, may be located only in the edge region 40, or may be located in both the gap region 20 and the edge region 40. The side wall of the piezoelectric layer 2 adjacent to the second sub-opening 42 may be perpendicular to the lower surface of the piezoelectric layer 2 (i.e., the surface of the piezoelectric layer 2 adjacent to the substrate 1 side), or may be inclined toward the electrode finger region 10. Wherein the height of the second sub-opening 42 in the second direction Y is much smaller than the height of the first sub-opening 41 in the second direction Y.

In case the resonator further comprises a first dielectric layer 5, the first dielectric layer 5 fills the first sub-opening 41 and the second sub-opening 42. In the case where the first dielectric layer 5 has a stacked structure, the first sub-opening 41 and the second sub-opening 42 may be filled with the same film layer or may be filled with different film layers.

For example, the first sub-opening 41 penetrates the piezoelectric layer 2 in the second direction Y, and the second sub-opening 42 is located at a side of the piezoelectric layer 2 close to the first sub-opening 41 and is located 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 is filled in the second sub-opening 42 and is located at the bottom of the first sub-opening 41, and the first film layer 51 is filled in the first sub-opening 41.

In some embodiments, as shown in fig. 23, the electrode fingers may also extend to a portion of the interface between the piezoelectric layer 2 and the opening 4. In case the opening 4 is located in the first gap sub-region 20a, the second electrode finger 32 extends in the first direction X in the electrode finger region 10 and the second gap sub-region 20b and extends to a part of the interface between the piezoelectric layer 2 and the opening 4 in the first gap sub-region 20 a. In case the opening 4 is located in the second gap sub-region 20b, the first electrode finger 31 extends in the first direction X in the electrode finger region 10 and the first gap sub-region 20a and extends to a part of the interface between the piezoelectric layer 2 and the opening 4 in the second gap sub-region 20 b.

In case the opening 4 is filled with the first dielectric layer 5, the electrode fingers extend to a part of the interface between the piezoelectric layer 2 and the first dielectric layer 5, i.e. the extension of the electrode fingers is located between the piezoelectric layer 2 and the first dielectric layer 5.

In some embodiments, the at least partial interface between the piezoelectric layer 2 and the opening 4 comprises at least one of a planar surface, a curved surface, and a broken line surface. In the case where the opening 4 is filled with the first dielectric layer 5, 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 broken line surface. Wherein the fold line surface may comprise a step surface.

As shown in fig. 1 and 3, all interfaces between the piezoelectric layer 2 and the opening 4 are inclined toward the electrode finger region 10, and the interfaces between the piezoelectric layer 2 and the opening 4 are inclined planes. In the case of filling the opening 4 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 10, and the interface is an inclined plane.

As shown in fig. 24 and 25, the entire interface between the piezoelectric layer 2 and the opening 4 has a tendency to tilt toward the electrode finger region 10, and the interface between the piezoelectric layer 2 and the opening 4 has a fold line surface having a tendency to tilt, such as a step surface having a tendency to tilt. Wherein each of the step surfaces of fig. 24 is composed of a vertical surface (vertical surface being perpendicular to the first direction X) and a horizontal surface (horizontal surface being perpendicular to the second direction Y), and the size of each of the step surfaces is smaller than the wavelength. Each of the step surfaces of fig. 25 is composed of an inclined surface (inclined surface inclined toward the direction of the electrode finger 10) and a horizontal surface. In the case where 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 in the direction of the electrode finger 10, and the interface is a stepped surface in an inclined tendency.

As shown in fig. 26, all the interfaces between the piezoelectric layer 2 and the opening 4 are inclined toward the electrode finger 10, and the interfaces between the piezoelectric layer 2 and the opening 4 are inclined curved surfaces that may be recessed toward the electrode finger 10. In the case where 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.

As shown in fig. 22, a portion of the interface between the piezoelectric layer 2 and the opening 4 is inclined toward the electrode finger region 10, and the portion 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 may be a vertical plane. In case the opening 4 is filled with the first dielectric layer 5, a part of the interface between the piezoelectric layer 2 and the first dielectric layer 5 is inclined towards the electrode finger 10 and is an inclined plane, the remaining interface may be a vertical plane.

As shown in fig. 27, a portion of the interface between the piezoelectric layer 2 and the opening 4 is inclined toward the electrode finger region 10, and the portion 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 may be a vertical plane. In the case where the opening 4 is filled with the first dielectric layer 5, a 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 may be a vertical plane.

In some embodiments, as shown in fig. 1, the resonator further comprises a second dielectric layer 6. The second dielectric layer 6 is located in the bus bar area 30, and the second dielectric layer 6 is located between the substrate 1 and the electrode layer 3. In case the base 1 comprises a substrate 11 and a support layer 12, the second dielectric layer 6 is located between the support layer 12 and the electrode layer 3.

As shown in connection with fig. 2, the second dielectric layer 6 is located in the first busbar zone 30a and the second busbar zone 30b, 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.

The second dielectric layer 6 may comprise one or more combinations of SiO ₂、Si₃N₄、Al₂O₃、Ta₂O₅, ALN, siC, etc. The material of the second dielectric layer 6 and the first dielectric layer 5 may be the same or different.

According to the resonator provided by the embodiment of the application, the opening is arranged at the edge of the piezoelectric layer, so that the opening is at least positioned in the gap region, and at least part of the interface between the piezoelectric layer and the opening is inclined towards the direction of the electrode finger region, so that the stray mode transmitted to the gap region is reflected to the substrate, and the stray mode is prevented from being reflected back to the electrode finger region, thereby inhibiting the stray mode and improving the performance of the resonator while ensuring the propagation characteristic of the main mode.

Accordingly, the embodiment of the present application further provides a filter, including the resonator in the above embodiment, which is not described in detail herein.

According to the filter provided by the embodiment of the application, the opening is arranged at the edge of the piezoelectric layer, so that the opening is at least positioned in the gap region, and at least part of the interface between the piezoelectric layer and the opening is inclined towards the direction of the electrode finger region, so that the stray mode transmitted to the gap region is reflected to the substrate, and the stray mode is prevented from being reflected back to the electrode finger region, thereby inhibiting the stray mode while ensuring the propagation characteristic of the main mode, improving the performance of the resonator and further improving the performance of the filter.

Accordingly, the embodiment of the present application further provides an electronic device including the filter in the above embodiment, which is not described in detail herein.

According to the electronic device provided by the embodiment of the application, the opening is arranged at the edge of the piezoelectric layer, so that the opening is at least positioned in the gap region, and at least part of the interface between the piezoelectric layer and the opening is inclined towards the direction of the electrode finger region, so that the stray mode transmitted to the gap region is reflected to the substrate, and the stray mode is prevented from being reflected back to the electrode finger region, thereby inhibiting the stray mode while ensuring the propagation characteristic of the main mode, improving the performance of the resonator, and further improving the performance of the electronic device.

The terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged, as appropriate, such that embodiments of the present application may be implemented in sequences other than those illustrated or described herein, and that the objects identified by "first," "second," etc. are generally of a type, and are not limited to the number of objects, such as the first object may be one or more.

In the description of the present application, "plurality" means two or more.

In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the spirit and scope of the application as defined by the appended claims and their equivalents.

Claims (15)

1. A kind of resonator which is used for the resonance of the liquid crystal, characterized by comprising the following steps:

the substrate comprises an electrode finger area, bus areas positioned on two opposite sides of the electrode finger area along a first direction, and a gap area positioned between the electrode finger area and the bus areas;

the piezoelectric layer is positioned in the electrode finger area and the gap area and is positioned at one side of the substrate along the second direction; the edge of the piezoelectric layer is provided with an opening, the opening is at least positioned in the gap area, and at least part of the interface between the piezoelectric layer and the opening is inclined towards the direction of the electrode finger area;

and the electrode layer is positioned at the electrode finger area, the gap area and the bus area and is positioned at one side of the piezoelectric layer, which is away from the substrate.

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

3. The resonator of claim 1, wherein an orthographic projection of a top of the opening onto the substrate coincides with the gap region.

4. The resonator of claim 1, wherein the electrode finger region comprises an edge region proximate the gap region;

The opening is located in the gap region and the edge region.

5. The resonator of claim 1, wherein the opening comprises a first sub-opening and a second sub-opening in communication;

the first sub-opening is at least located in the gap area, the interface between the piezoelectric layer and the first sub-opening is inclined towards the direction of the electrode finger area, and the second sub-opening is located on one side, close to the first sub-opening, of the piezoelectric layer.

6. The resonator of claim 5, wherein the second sub-opening is located at a bottom of the first sub-opening.

7. The resonator of claim 1, wherein the electrode layer comprises electrode fingers located in the electrode finger region and extending in the first direction;

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

8. The resonator of claim 1, further comprising a first dielectric layer;

the first dielectric layer fills in the opening.

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

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

11. The resonator of claim 1, wherein the at least partial interface between the piezoelectric layer and the opening comprises at least one of a planar surface, a curved surface, and a broken line surface, the broken line surface comprising a stepped surface.

12. The resonator according to claim 1, characterized in that the piezoelectric layer comprises lithium tantalate, the angle of inclination of the at least part of the interface between the piezoelectric layer and the opening being between 5 ° and 30 °.

13. The resonator according to any of claims 1-12, characterized in that the resonator further comprises a second dielectric layer;

The second dielectric layer is located in the bus bar area and between the substrate and the electrode layer.

14. A filter comprising a resonator as claimed in any one of claims 1 to 13.

15. An electronic device comprising a filter as claimed in claim 14.