A piezoelectric resonator

Abstract

The embodiment of the present application provides a Lame mode piezoelectric resonator, which comprises a substrate, a piezoelectric layer, a vibrator structure, a driving electrode, a sensing electrode and an anchor point structure; the anchor point structure is located on both sides of the vibrator structure and is used for supporting the vibrator structure; the piezoelectric layer is located on the vibrator structure and the anchor point structure; the vibrator structure is used as a bottom electrode of the piezoelectric layer and is connected with the ground; the driving electrode and the sensing electrode are respectively located on the upper surface of the piezoelectric layer; the piezoelectric layer comprises a plurality of first electrode fingers and a plurality of second electrode fingers which are alternately arranged in sequence; the first electrode fingers are connected with the driving electrode, and the second electrode fingers are connected with the sensing electrode; the distance between the central axis of each first electrode finger and the central axis of the adjacent second electrode finger is not more than ±10% of the thickness of the vibrator structure, so that the vibrator structure is excited in the thickness direction to generate the Lame mode, and the anchor point structure is optimized to improve the quality factor of the piezoelectric resonator.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more particularly to a piezoelectric resonator. Background Technology

[0002] Among various vibration modes, the Lame mode, as an in-plane vibration mode, is considered an ideal choice for achieving high-performance, low-phase-noise piezoelectric resonators and filters due to its typically high quality factor (Q value), good power handling capability, and low thermoelastic damping. Capacitive Lame resonators can achieve extremely high Q values, but they require a DC bias during operation, have dynamic impedances reaching kΩ, and low electromechanical coupling coefficients, resulting in high power consumption and complex subsequent circuitry. Piezoelectric resonators typically have low dynamic impedance and can also achieve high Q values; however, piezoelectric resonators fabricated using semiconductor processes usually involve growing piezoelectric materials on silicon substrates. Due to the in-plane isotropic nature of piezoelectric materials, their structure makes it difficult to excite in-plane Lame modes. Summary of the Invention

[0003] To address the existing technical problems, this application provides a piezoelectric resonator that can effectively excite the Lame mode.

[0004] This application provides a piezoelectric resonator, including: a substrate, a piezoelectric layer, an oscillator structure, a driving electrode, a sensing electrode, and an anchor structure; the anchor structure is fixedly connected to both sides of the oscillator structure, and the piezoelectric layer is located on the oscillator structure and the anchor structure; the driving electrode and the sensing electrode are respectively located on the upper surface of the piezoelectric layer; the piezoelectric layer includes a plurality of first electrode fingers and a plurality of second electrode fingers arranged alternately in sequence, the first electrode fingers are connected to the driving electrode, and the second electrode fingers are connected to the sensing electrode; the absolute value of the difference between the distance between the central axis of each first electrode finger and the central axis of the adjacent second electrode finger and the thickness of the oscillator structure is less than or equal to 10% of the thickness of the oscillator structure; wherein, the central axis is the central axis along the extension direction of the electrode finger length, and the thickness is the dimension along the stacking direction of the piezoelectric layer and the oscillator structure.

[0005] In one embodiment, the oscillator structure is made of heavily doped single-crystal silicon with a doping concentration of not less than 10^19 atoms / cm^3; the oscillator structure is used as the bottom electrode of the piezoelectric layer and is grounded.

[0006] In one embodiment, the device further includes: a first connection structure, wherein the sensing electrode and / or the driving electrode, and the piezoelectric layer are also located on the first connection structure; the oscillator structure is fixedly connected to the anchor structure through the first connection structure; the width of the first connection structure is smaller than the width of the driving electrode and / or the sensing electrode, and the width is a dimension along the electrode finger arrangement direction.

[0007] Thus, by forming a piezoelectric region through alternating interdigitated electrodes and controlling the relative deviation between the spacing of adjacent interdigitated electrodes and the thickness of the oscillator structure to not exceed ±10%, the periodic electric field formed by the interdigitated electrodes is matched with the shear elastic wave formed in the thickness direction of the oscillator structure, thereby realizing the Lame vibration mode of the oscillator structure in the thickness direction. In addition, by optimizing the connection method between the first connection structure and the anchor point, the energy leaked by the elastic wave through the anchor point when the piezoelectric resonator vibrates is reduced, thereby improving the Q value of the Lame resonator and realizing the excitation of the piezoelectric Lame mode resonator, while also possessing a high Q value. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the displacement field within the Lame modal surface; Figure 2a This is a schematic diagram of the structure of a piezoelectric resonator in one embodiment of this application; Figure 2b for Figure 2a Cross-sectional view in the AA direction; Figure 3a This is a schematic diagram of the Lame mode shape in one embodiment of this application; Figure 3b This is a schematic diagram of the vibration modes of the cross sections along the X and Z directions in one embodiment of this application; Figure 4 This is a schematic diagram of the structure of a piezoelectric resonator in another embodiment of this application; Figure 5 This is a schematic diagram of the structure of a piezoelectric resonator in another embodiment of this application; Figure 6 This is a schematic diagram of the piezoelectric resonator in another embodiment of this application; Figure 7 This is a top view of the second connection structure in one embodiment of this application; Figure 8 This is a schematic diagram comparing the normalized Q values ​​with and without a flexible beam in one embodiment of this application.

[0009] Explanation of reference numerals in the attached figures 1. Oscillator structure; 2. Piezoelectric layer; 21. First electrode finger; 22. Second electrode finger; 3. Driving electrode; 4. Sensing electrode; 5. Anchor point structure; 6. First connecting structure; 61. Connecting part; 7. Second connecting structure; 71. Hollowed-out area. Detailed Implementation

[0010] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0011] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0012] In the following description, the phrase "some embodiments" refers to a subset of all possible embodiments. It should be noted that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.

[0013] In the following description, the terms "first," "second," and "third" are used merely to distinguish similar objects and do not represent a specific ordering of the objects. It is understood that "first," "second," and "third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0014] The inventors of this application have conducted the following analysis regarding the design of piezoelectric resonators, based on relevant research on Lame modes: like Figure 1The diagram shows the distribution of the internal displacement field under the Lame mode, including mutually perpendicular X and Y directions. It can be seen that during in-plane vibration of the Lame mode, adjacent sides elongate and contract sequentially, meaning there is a 180° phase difference between the X and Y directions. At a certain moment, the stress fields in the X and Y directions are equal in magnitude but opposite in direction. Therefore, when a layered driving method is used, i.e., the piezoelectric layer covers the entire surface of the Lame structure, the charges on the piezoelectric electrodes on the Lame structure will cancel each other out, making effective driving of the planar Lame mode impossible. The Lame mode is a pure shear mode; its volume remains constant during vibration, so thermoelastic losses are almost negligible. Electrostatic Lame mode resonators can achieve ultra-high quality factors of hundreds of thousands through anchor point optimization, but their dynamic impedance and power consumption are relatively high. In contrast, piezoelectric resonators generally have low dynamic impedance. By driving the Lame structure with piezoelectricity, a resonator with high Q value and low dynamic impedance can be achieved.

[0015] Therefore, the inventors proposed a piezoelectric layer based on an alternating interdigitated electrode structure. By connecting the driving electrode and the sensing electrode respectively, an electric field is formed, avoiding the mutual cancellation of charges. Furthermore, since the spacing between adjacent interdigitated electrodes is approximately equal to the thickness of the oscillator structure, the thickness-direction Lame mode is effectively excited in the piezoelectric resonator, thereby obtaining better resonance performance.

[0016] like Figure 2a As shown, this application provides a piezoelectric resonator, including: a substrate, an oscillator structure 1, a piezoelectric layer 2, a driving electrode 3, a sensing electrode 4, and an anchor structure 5; the anchor structure 5 is fixedly connected to both sides of the oscillator structure 1, and the piezoelectric layer 2 is located on the oscillator structure 1 and the anchor structure 5; the driving electrode 3 and the sensing electrode 4 are respectively located on the upper surface of the piezoelectric layer 2; The piezoelectric layer 2 includes a plurality of first electrode fingers 21 and a plurality of second electrode fingers 22 arranged alternately in sequence. The first electrode fingers 21 are connected to the driving electrode 3, and the second electrode fingers 22 are connected to the sensing electrode 4. The absolute value of the difference between the distance h between the central axis of each first electrode finger 21 and the central axis of the adjacent second electrode finger 22 and the thickness t of the oscillator structure 1 is less than or equal to 10% of the thickness of the oscillator structure 1, that is, the relative deviation does not exceed ±10% of the thickness of the oscillator structure 1; wherein, the central axis is the central axis along the extension direction of the electrode finger length, and the thickness is the dimension along the stacking direction of the piezoelectric layer 2 and the oscillator structure 1.

[0017] In one embodiment, the driving electrode 3 serves as the input terminal, and the oscillator structure 1 serves as the bottom electrode of the piezoelectric layer 2 and is grounded, converting external electrical signals into mechanical motion through the piezoelectric layer 2. The sensing electrode 4 serves as the output terminal, utilizing the piezoelectric layer 2 to convert mechanical motion into electrical signals for output.

[0018] In one embodiment, the edge of the driving electrode 3 is aligned with the edge of the piezoelectric layer 2 below the driving electrode 3, and / or the edge of the sensing electrode 4 is aligned with the edge of the piezoelectric layer 2 below the sensing electrode 4.

[0019] The piezoelectric resonator operates in the thickness shear Lame mode, and the mode shape of its oscillator structure 1 is as follows: Figure 3a As shown, the schematic diagrams of the vibration modes along the X and Z directions are as follows: Figure 3b As shown. The driving electrode 3 receives an external electrical signal and outputs an electric field to the first electrode finger 21 based on the external electrical signal, thereby driving the oscillator structure 1 to resonate. The resonance of the oscillator structure 1 causes the second electrode finger 22 to generate induced charge, which is then output through the induction electrode 4.

[0020] In one embodiment, the anchor structure 5 is divided into two parts, located on both sides of the oscillator structure 1. One part of the anchor structure 5 is provided with a driving electrode 3, and the other part of the anchor structure 5 is provided with a sensing electrode 4. The driving electrode 3 and the sensing electrode 4 are respectively fixed to the substrate through the corresponding anchor structure 5.

[0021] For example, the edge of the driving electrode 3 is aligned with the edge of its corresponding anchor structure 5, and / or the edge of the sensing electrode 4 is aligned with the edge of its corresponding anchor structure 5.

[0022] In one embodiment, the oscillator structure 1 can be used for grounding. The material of the oscillator structure 1 can be heavily doped single crystal silicon with a doping concentration of not less than 10^19 atoms / cm^3. Since the mechanical damping of silicon is usually smaller than that of metal materials, using heavily doped single crystal silicon to replace traditional metal as the conductive layer can reduce mechanical loss and improve the quality factor.

[0023] In a top view, the oscillator structure 1 is rectangular, and the anchor point structures 5 are located on opposite sides of the oscillator structure, and are spaced apart from and parallel to the two sides of the oscillator structure 1 in the second direction. The driving electrode 3 and the sensing electrode 4 are located on the anchor point structures 5 on both sides.

[0024] In one embodiment, such as Figure 2a and Figure 2b As shown, the piezoelectric layer 2 may include a plurality of first electrode fingers 21 and a plurality of second electrode fingers 22 arranged alternately in sequence, as well as a first busbar and a second busbar. Figure 2b for Figure 2aThe longitudinal cross-sectional view in the AA direction, which is the cross-sectional view of the section formed in the YZ direction. Multiple first electrode fingers 21 are connected to the first busbar, and multiple second electrode fingers 22 are connected to the second busbar.

[0025] In one embodiment, the upper surface of the first electrode finger 21 and the upper surface of the first busbar are connected to the driving electrode 3, and the upper surface of the second electrode finger 22 and the upper surface of the second busbar are connected to the sensing electrode 4.

[0026] In one embodiment, the multiple first electrode fingers 21 and multiple second electrode fingers 22 arranged alternately in sequence means that each first electrode finger 21 is adjacent to a second electrode finger 22, and each second electrode finger 22 is adjacent to a first electrode finger 21.

[0027] In one embodiment, the first busbar is perpendicular to the connected first electrode finger 21, and the second busbar is perpendicular to the connected second electrode finger 22. For example, multiple first electrode fingers 21 and multiple second electrode fingers 22 are arranged alternately in a first direction, and the first busbar and second busbar are arranged along a second direction, which is perpendicular to the first direction in the plane of the piezoelectric layer 2. The second direction is the direction in which the electrode fingers extend, and the electrode fingers include the first electrode finger 21 and the second electrode finger 22.

[0028] For example Figure 2a As shown, the first direction is the Y direction, the second direction is the X direction, and the stacking direction of the piezoelectric layer 2 and the oscillator structure 1, i.e. the thickness direction, is the Z direction.

[0029] In one embodiment, the distance between the central axis of each first electrode finger 21 and the central axis of the adjacent second electrode finger 22, that is, the distance between the central axes of any pair of adjacent first electrode fingers 21 and second electrode fingers 22, can be expressed as h, where the central axis is the central axis along the direction of extension of the electrode finger length, that is, the central axis along the second direction.

[0030] The thickness of the oscillator structure 1 can be expressed as t, which refers to the dimension along the stacking direction of the piezoelectric layer 2 and the oscillator structure 1, that is, the dimension perpendicular to the plane where the piezoelectric layer 2 is located. h≈t, that is, the relative error between the difference between h and t does not exceed ±10%.

[0031] In one embodiment, h = t.

[0032] In one embodiment, the first electrode finger 21 and the second electrode finger 22 are the same size. The distance between the central axis of each first electrode finger 21 and the central axis of the adjacent second electrode finger 22 can also refer to the sum of the minimum distance between the edge of each first electrode finger 21 and the edge of the adjacent second electrode finger 22 and the width of the first electrode finger 21 or the second electrode finger 22.

[0033] The minimum distance between the edges of the first electrode finger 21 and the adjacent second electrode finger 22 refers to the distance between the two opposite edges of the first electrode finger 21 and the adjacent second electrode finger 22. The width of the first electrode finger 21 or the second electrode finger 22 refers to the dimension of the first electrode finger 21 or the second electrode finger 22 in the first direction.

[0034] Thus, by forming a piezoelectric layer 2 through alternating interdigitated electrodes, and controlling the relative deviation between the spacing of adjacent interdigitated electrodes and the thickness of the oscillator structure 1 within ±10%, the spacing is approximately equal to the thickness of the oscillator structure 1. This achieves matching between the periodic electric field distribution formed by the interdigitated electrodes and the shear elastic wave formed in the thickness direction of the oscillator structure 1, thereby realizing the effective excitation of the thickness Lame vibration mode.

[0035] In some embodiments, such as Figure 4 As shown, it also includes: a first connection structure 6. The sensing electrode 4 and / or the driving electrode 3 are also located on the first connection structure 6, and the piezoelectric layer 2 is also located on the first connection structure 6; the oscillator structure 1 is fixedly connected to the anchor point structure 5 through the first connection structure 6; the width of the first connection structure 6 is smaller than the width of the first electrode finger 21 and / or the second electrode finger 22, and the width is the dimension along the electrode finger arrangement direction.

[0036] The upper surfaces of the plurality of first electrode fingers 21 are all connected to the driving electrode 3, and the upper surfaces of the plurality of second electrode fingers 22 are all connected to the sensing electrode 4.

[0037] In one embodiment, the first connecting structure 6 is used to connect the anchor structure 5 and the oscillator structure 1. For example, the first connecting structure 6 may also include two parts, which are respectively connected to both sides of the oscillator structure 1. One part is connected between the oscillator structure 1 and the anchor structure 5 below the driving electrode 3, and the other part is connected between the oscillator structure 1 and the anchor structure 5 below the sensing electrode 4.

[0038] In one embodiment, the edge of the driving electrode 3 or the sensing electrode 4 is aligned with the edge of the first connection structure 6.

[0039] like Figure 3b The diagram shows the mode shape of the oscillator structure 1 in the XZ section. The device excites a mode shape formed by the combination of multiple Lame modes in the thickness direction, and the phase difference between adjacent Lame modes is 180°. It can be seen from the mode shape diagram that the vibration nodes are located at the center of both ends of the first electrode finger 21 and the second electrode finger 22 in the length direction of the oscillator structure 1, where the vibration displacement is the smallest.

[0040] Thus, by connecting the anchor structure 5 to the oscillator structure 1 through a connection structure whose width does not exceed the width of the first electrode finger 21 and / or the second electrode finger 22, and based on the connection position with small vibration displacement, the energy loss generated through the anchor structure 5 is reduced, thereby improving the quality factor (Q value).

[0041] In some embodiments, the first connection structure 6 corresponding to the first electrode finger 21 and the first connection structure 6 corresponding to the second electrode finger 22 are symmetrically distributed based on the oscillator structure 1.

[0042] Wherein, the first electrode refers to the first connection structure 6 corresponding to 21, which is the first connection structure 6 connected to the anchor point structure 5 below the driving electrode 3; the second electrode refers to the first connection structure 6 corresponding to 22, which is the first connection structure 6 connected to the anchor point structure 5 below the sensing electrode 4.

[0043] In one embodiment, the oscillator structure 1 is symmetrically distributed, that is, symmetrically distributed along the central axis of the oscillator structure 1 in the first direction.

[0044] In this way, the two connecting beams are symmetrically distributed, and the connection support can be achieved by matching the symmetry of the vibration modes. At the same time, the parasitic modes, stress imbalance and process errors caused by asymmetry are eliminated, and finally the resonator performance of low loss, high Q value and high consistency is achieved.

[0045] In some embodiments, such as Figure 5 As shown, the first connection structure 6 includes multiple connection segments 61, each of the first electrode fingers 21 is aligned with one of the connection segments 61, and / or each of the second electrode fingers 22 is aligned with one of the connection segments 61.

[0046] In one embodiment, each first electrode finger 21 is aligned with a section of connection 61, that is, each first electrode finger 21 is aligned with a section of connection 61 on the anchor structure 5 below the drive electrode 3.

[0047] For example, the first connection structure 6 corresponding to the first electrode finger 21 and the first connection structure 6 corresponding to the second electrode finger 22 are symmetrically distributed based on the oscillator structure 1, that is, each first electrode finger 21 is also aligned with a section of connection 61 on the anchor point structure 5 connected below the sensing electrode 4.

[0048] In one embodiment, each second electrode finger 22 is aligned with a section of the connecting portion 61, that is, each second electrode finger 22 is aligned with a section of the connecting portion 61 on the anchor point structure 5 below the sensing electrode 4.

[0049] For example, the first connection structure 6 corresponding to the first electrode finger 21 and the first connection structure 6 corresponding to the second electrode finger 22 are symmetrically distributed based on the oscillator structure 1, that is, each second electrode finger 22 is also aligned with a section of connection 61 on the anchor point structure 5 connected below the driving electrode 3.

[0050] In one embodiment, the number of connection portions 61 connected to the anchor structure 5 below the driving electrode 3 can be equal to the number of first electrode fingers 21, or it can be greater than or less than the number of first electrode fingers 21.

[0051] In one embodiment, the number of connection portions 61 connected to the anchor structure 5 below the sensing electrode 4 can be equal to the number of second electrode fingers 22, or it can be greater than or less than the number of second electrode fingers 22.

[0052] In one embodiment, multiple connecting segments 61 are spaced apart, and the width of each connecting segment 61 in the first direction does not exceed the width of a first electrode finger 21 and / or a second electrode finger 22 in the first direction.

[0053] Thus, through the connection structure with multiple connecting sections 61 spaced apart, each connecting section can be aligned with a first electrode finger 21 or a second electrode finger 22, thereby achieving the matching of the distribution of the connection structure with the mode shape of the oscillator, thereby further reducing losses and improving the quality factor.

[0054] In some embodiments, such as Figure 6 As shown, it may further include: a second connection structure 7. The sensing electrode 4 and / or the driving electrode 3 are also located on the second connection structure 7, and the piezoelectric layer 2 is also located on the second connection structure 7. The first connection structure 6 is fixedly connected to the anchor point structure 5 through the second connection structure 7; the second connection structure 7 includes at least one hollow area 71; In one embodiment, the second connecting structure 7 can also be called a flexible beam. For example, if the dimension of the second connecting structure 7 along the electrode finger arrangement direction is greater than the dimension along the length direction of the electrode finger, then the second connecting structure 7 can form a smaller stiffness based on its longer length, which is beneficial to become the main deformation area, further reducing the energy transmitted to the anchor point, reducing anchor point loss, and improving the Q value.

[0055] In one embodiment, the second connection structure 7 may also include two parts located on both sides of the oscillator structure 1, one part being connected between the anchor point structure 5 below the driving electrode 3 and the corresponding first connection structure 6, and the other part being connected between the anchor point structure 5 below the sensing electrode 4 and the corresponding first connection structure 6.

[0056] In one embodiment, the second connecting structure 7 includes at least one hollow region 71, which can penetrate the second connecting structure 7 along the stacking direction of the piezoelectric layer 2 and the oscillator structure 1. For example, in a top view, the hollow region 71 can be located at the center of the second connecting structure 7. The stacking direction, which is also the thickness direction, can be represented by the Z direction in the figure.

[0057] For example, such as Figure 7 As shown, this is a top view of the hollowed-out area 71. In the top view direction, the geometric center of the hollowed-out area 71 can coincide with the geometric center of the second connecting structure 7.

[0058] In one embodiment, the second connecting structure 7 may include a first segment and a second segment. The first segment is along the electrode finger arrangement direction, and the hollowed-out area 71 is located on the first segment. The first segment is connected to the first connecting structure 6. The second segment may be the part connecting the first segment and the anchor point structure 5. The length of the second segment along the electrode finger arrangement direction may be less than the length of the first segment along the electrode finger arrangement direction.

[0059] Thus, the abrupt change in the transmission path is formed by the hollowed-out area 71 in the second connection structure 7. As a result, in the path of mechanical wave transmission from the oscillator structure 1 through the first connection structure 6 and the second connection structure 7 to the anchor structure 5, the impedance discontinuity on the mechanical wave propagation path can be caused by this abrupt structure, and part of the energy is reflected back to the resonant region, reducing the energy leakage from the anchor structure 5 and further improving the Q value.

[0060] In some embodiments, such as Figure 7 As shown, in a top view, the first distance L1 between the first edge of the hollow area 71 and the first edge of the second connecting structure 7 is less than the second distance L2 between the second edge of the hollow area 71 and the second edge of the second connecting structure 7; wherein, the first edge is perpendicular to the first connecting structure 6, and the second edge is perpendicular to the first edge.

[0061] In one embodiment, the first edge of the second connecting structure 7 is connected to the first connecting structure 6 or the anchor point structure 5, and the second edge is an edge in another direction perpendicular to the first edge. For example, the first edge is an edge parallel to the first direction, and the second edge is an edge parallel to the second direction.

[0062] Thus, by making the second connecting structure 7, which is hollowed out, different in size in different directions, impedance discontinuity is further formed on the mechanical wave propagation path, thereby reducing energy leakage of the anchor structure 5.

[0063] In some embodiments, the first distance is less than the width of the first connection structure 6.

[0064] The width of the first connecting structure 6 refers to the width along the direction of the electrode finger arrangement.

[0065] For example, the first distance may be less than or equal to 80%, 60%, 50%, etc., the width of the first connecting structure 6.

[0066] Thus, by having a smaller dimension in the second direction than the width of the first connecting structure 6, the hollow second connecting structure 7, combined with its longer length in the first direction, can further form a smaller stiffness, thereby facilitating the formation of the main deformation area and further reducing the energy of mechanical waves transmitted to the anchor structure 5.

[0067] Furthermore, the thickness-shear Lame mode inherits the deformation mechanism of pure shear in the Lame mode. Therefore, the thickness-shear Lame resonator has almost no thermoelastic loss. The resonator oscillator uses monocrystalline silicon, which has low mechanical loss. The material loss of the device mainly comes from the piezoelectric material. In addition, the anchor point becomes the main source of energy loss in the resonator. To further improve the Q value of the device, the anchor point loss is optimized by adding a flexible beam (i.e., the second connecting structure 7) between the connecting beam and the anchor point structure 5. Figure 8 As shown, the simulation results of the Q value of anchor structure 5 are presented, including the Q value of the resonator without the flexible beam and with the flexible beam, respectively, and normalized. Point A is the normalized Q value of anchor structure 5 without the flexible beam, and point B is the normalized Q value of anchor structure 5 with the flexible beam. It can be seen that by adding the flexible beam, the anchor Q value of the resonator is significantly improved.

[0068] Thus, by setting interdigitated electrodes and setting the electrode spacing to be approximately equal to the device thickness, the thickness Lame mode can be excited. By optimizing the connection structure of anchor point structure 5, the Q value of the device can be effectively improved, thereby realizing a piezoelectric Lame mode resonator with low dynamic impedance and high Q value.

[0069] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0070] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A piezoelectric resonator, characterized in that, include: Substrate, piezoelectric layer, oscillator structure, driving electrode, sensing electrode, and anchor point structure; The anchor point structure is fixedly connected to both sides of the oscillator structure, and the piezoelectric layer is located on the oscillator structure and the anchor point structure; the driving electrode and the sensing electrode are respectively located on the upper surface of the piezoelectric layer; The piezoelectric layer includes a plurality of first electrode fingers and a plurality of second electrode fingers arranged alternately in sequence. The first electrode fingers are connected to the driving electrode, and the second electrode fingers are connected to the sensing electrode. The absolute value of the difference between the distance between the central axis of each first electrode finger and the central axis of the adjacent second electrode finger and the thickness of the oscillator structure is less than or equal to 10% of the thickness of the oscillator structure; wherein, the central axis is the central axis along the length extension direction of the electrode finger, and the thickness is the dimension along the stacking direction of the piezoelectric layer and the oscillator structure.

2. The piezoelectric resonator according to claim 1, characterized in that, The edge of the driving electrode is aligned with the edge of the piezoelectric layer below the driving electrode, and / or the edge of the sensing electrode is aligned with the edge of the piezoelectric layer below the sensing electrode.

3. The piezoelectric resonator according to claim 1, characterized in that, The oscillator structure is made of heavily doped single-crystal silicon with a doping concentration of not less than 10^19 atoms / cm^3; the oscillator structure is used as the bottom electrode of the piezoelectric layer and is grounded.

4. The piezoelectric resonator according to claim 1, characterized in that, Also includes: The first connection structure, wherein the sensing electrode and / or the driving electrode, and the piezoelectric layer are also located on the first connection structure; The oscillator structure is fixedly connected to the anchor point structure through the first connecting structure; the width of the first connecting structure is smaller than the width of the first electrode finger and / or the second electrode finger, and the width is the dimension along the direction of electrode finger arrangement.

5. The piezoelectric resonator according to claim 4, characterized in that, The edge of the driving electrode or the sensing electrode is aligned with the edge of the first connection structure.

6. The piezoelectric resonator according to claim 5, characterized in that, The first electrode refers to the first connection structure, and the first connection structure corresponding to the second electrode is symmetrically distributed based on the oscillator structure.

7. The piezoelectric resonator according to claim 5, characterized in that, The first connection structure includes multiple connection segments spaced apart, each of the first electrode fingers being aligned with one of the connection segments, and / or each of the second electrode fingers being aligned with one of the connection segments.

8. The piezoelectric resonator according to any one of claims 4 to 7, characterized in that, Also includes: The second connection structure, wherein the sensing electrode and / or the driving electrode, and the piezoelectric layer are also located on the second connection structure; The first connecting structure is fixedly connected to the anchor point structure through the second connecting structure; the second connecting structure includes at least one hollow area.

9. The piezoelectric resonator according to claim 8, characterized in that, On a top-view plane, the first distance between the first edge of the hollowed-out area and the first edge of the second connecting structure is less than the second distance between the second edge of the hollowed-out area and the second edge of the second connecting structure; wherein, the first edge is perpendicular to the first connecting structure, and the second edge is perpendicular to the first edge.

10. The piezoelectric resonator according to claim 9, characterized in that, The first distance is less than the width of the first connection structure.

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