Piezoelectric driving silicon-based micro-electro-mechanical resonator with high quality factor
By employing a dielectric and metal layer encapsulation design in a piezoelectric-driven silicon-based microelectromechanical resonator, the problem of reduced quality factor caused by thermal expansion coefficient mismatch was solved, achieving high quality factor and low electrical loss across the entire temperature range, thus improving the reliability and performance of the device.
Patent Information
- Application Number
- CN202411074949.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-07
- Publication Date
- 2026-02-10
AI Technical Summary
Existing piezoelectric-driven silicon-based microelectromechanical resonators experience a decrease in quality factor Q at different operating temperatures due to the mismatch in thermal expansion coefficients between the silicon layer and the first metal layer of the device, resulting in tensile or tensile stress at the interface.
A novel structural design is adopted, in which a dielectric layer is wrapped by a first metal layer and a device silicon layer to form a single or multi-polar bottom electrode layer. The dielectric layer edge is designed with a bevel, and the multi-layer metal and dielectric layer structure is combined to optimize the electrode layer coverage and reduce the impact of thermal stress.
Maintaining a high quality factor (Q) and low electrical losses across the entire temperature range reduces series resonant impedance and improves device reliability and performance stability.
Smart Images
Figure CN121508481A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of resonators, and more particularly, to a piezoelectric-driven silicon-based micro-electro-mechanical resonator with high quality factor. BACKGROUND
[0002] The micro-electro-mechanical oscillator technology with a silicon-based micro-electro-mechanical resonator driven by electrostatic as a core device is becoming mature under the prior art, and is expected to become a substitute for the traditional quartz oscillator, thereby having smaller size, lower manufacturing cost, and higher reliability.
[0003] With the development of piezoelectric thin film materials, compared with the silicon-based micro-electro-mechanical resonator driven by electrostatic, the silicon-based micro-electro-mechanical resonator based on piezoelectric driving shows lower motional impedance and higher electromechanical coupling coefficient, thereby being conducive to reducing the power consumption and phase noise of the oscillator. The piezoelectric-driven silicon-based micro-electro-mechanical resonator does not need to add an electrostatic bias voltage, thus reducing the error term generated on the output signal due to the power supply jitter; at the same time, the piezoelectric-driven silicon-based micro-electro-mechanical resonator does not need to form a sub-micron level silicon layer slit in processing, thereby reducing the process difficulty, being conducive to improving the device yield, and being conducive to further miniaturization of the device.
[0004] The basic layer structure of the piezoelectric-driven silicon-based micro-electro-mechanical resonator under the prior art is shown in FIG. 1(a) or 1(b): including a substrate silicon layer 101 with a cavity 102, and a vibrating membrane layer arranged on the substrate silicon layer 101 to cover the cavity 102, a first bonding layer 103 or a second bonding layer 204 is arranged between the substrate silicon layer 101 and the vibrating membrane layer to adhere to the surface of the substrate silicon layer 101 with the cavity 102 or to adhere to the surface of the vibrating membrane layer, the first bonding layer 103 and the second bonding layer 204 serve as an insulating layer between the device silicon layer 201 and the substrate silicon layer 101, and the material of the first bonding layer 103 and the second bonding layer 204 is silicon dioxide.
[0005] The corresponding region of the cavity 102 on the vibrating membrane layer has a groove 301 penetrating the cavity 102, and the groove 301 defines the resonator boundary shape located above the cavity. The vibrating membrane layer includes, in order from the cavity side and upward, a device silicon layer 201, a piezoelectric layer 202, and a top electrode layer 203.
[0006] In the laminated structure of the piezoelectric driven silicon-based micro-electro-mechanical resonator, the device silicon layer 201 is usually made of doped silicon layer, thus having low resistivity characteristics, and can be used as the bottom electrode layer. Optionally, the basic laminated structure has at least one electrical connection hole 302 to connect the device silicon layer 201 to the electrode pin on the top electrode layer 203, thus facilitating the application of electrical signals.
[0007] The second example of the laminated structure of the piezoelectric driven silicon-based micro-electro-mechanical resonator in the prior art can also have a first metal layer 205 between the device silicon layer 201 and the piezoelectric layer 202, which is in direct contact with the device silicon layer 201 and thus serves as a bottom electrode layer together, as shown in Figure 2 This structure can reduce the equivalent series resistance of the bottom electrode layer and improve the quality factor Q value of the resonator. The technical problem existing in the second example of the prior art is that the first metal layer 205 and the device silicon layer 201 have a large mismatch in the coefficient of thermal expansion, and at different operating temperatures, usually in the temperature range of -55°C to 125°C, or -45°C to 85°C, the interface between the two is prone to tensile stress or tensile stress, thus generating thermal-elastic loss, which reduces the quality factor Q value compared to the normal temperature working state.
[0008] Therefore, the existing problems need to be further improved and developed. SUMMARY
[0009] (I) Invention purpose: To solve the above-mentioned problems existing in the prior art, the purpose of the present application is to provide a piezoelectric driven silicon-based micro-electro-mechanical resonator with a novel structure, so that the piezoelectric driven silicon-based micro-electro-mechanical resonator has a high quality factor.
[0010] (II) Technical solution: In order to solve the above technical problems, the technical solution provides a piezoelectric driven silicon-based micro-electro-mechanical resonator with a high quality factor, which comprises a substrate silicon layer with a cavity and a vibrating membrane layer arranged on the substrate silicon layer to cover the cavity, wherein the vibrating membrane layer comprises, from bottom to top, a bottom electrode layer, a piezoelectric layer and a top electrode layer; the bottom electrode layer comprises, from bottom to top, a device silicon layer, a dielectric layer and a first metal layer; the dielectric layer covers part of the device silicon layer, the first metal layer covers at least part of the dielectric layer, and the first metal layer at least partially extends to the outside of the dielectric layer and covers at least part of the device silicon layer.
[0011] The piezoelectric driven silicon-based micro-electro-mechanical resonator with a high quality factor, wherein the dielectric layer is completely wrapped by the device silicon layer and the first metal layer.
[0012] A piezoelectric driven silicon-based micro-electro-mechanical resonator with high quality factor, wherein the corresponding region of the cavity on the diaphragm layer is an effective vibration region, and the edge of the dielectric layer is located within the effective vibration region, or outside the effective vibration region, or coincides with the effective vibration region.
[0013] A piezoelectric driven silicon-based micro-electro-mechanical resonator with high quality factor, wherein a groove is provided in the corresponding region of the cavity on the diaphragm layer to define the boundary condition of the effective vibration region, and the groove penetrates the diaphragm layer.
[0014] A piezoelectric driven silicon-based micro-electro-mechanical resonator with high quality factor, wherein the edge of the dielectric layer is located within the boundary of the effective vibration region defined by the groove; or the edge of the dielectric layer is located outside the boundary of the effective vibration region defined by the groove, but still within the corresponding region of the edge of the cavity; or the edge of the dielectric layer extends to the corresponding region outside the edge of the cavity.
[0015] A piezoelectric driven silicon-based micro-electro-mechanical resonator with high quality factor, wherein the edge of the dielectric layer is etched into a bevel; the inclination angle of the edge bevel of the dielectric layer is less than 80°, or the inclination angle of the edge bevel of the dielectric layer is less than 60°, or the inclination angle of the edge bevel of the dielectric layer is less than 30°.
[0016] A piezoelectric driven silicon-based micro-electro-mechanical resonator with high quality factor, wherein the thickness of the dielectric layer is between 5 nm and 500 nm.
[0017] A piezoelectric driven silicon-based micro-electro-mechanical resonator with high quality factor, wherein the dielectric layer comprises a first dielectric layer and a second dielectric layer stacked one above the other, and the second dielectric layer completely covers the upper surface of the first dielectric layer; the first metal layer covers the surface of the second dielectric layer, the side surface of the first dielectric layer, and the surface of the device silicon layer not covered by the first dielectric layer.
[0018] A piezoelectric driven silicon-based micro-electro-mechanical resonator with high quality factor, wherein the edge of the second dielectric layer is etched into a bevel; the inclination angle of the edge bevel of the second dielectric layer is less than 30°, or the inclination angle of the edge bevel of the second dielectric layer is less than 15°.
[0019] A piezoelectric driven silicon-based micro-electro-mechanical resonator with high quality factor, wherein the thickness of the second dielectric layer is greater than the thickness of the first dielectric layer.
[0020] A piezoelectric driving silicon-based micro-electro-mechanical resonator with high quality factor, wherein a third metal layer is arranged between the first metal layer and the dielectric layer, the third metal layer completely covers the upper surface of the dielectric layer, and the first metal layer covers the surface of the third metal layer, the side surface of the dielectric layer and the surface of the device silicon layer not covered by the dielectric layer.
[0021] A piezoelectric driving silicon-based micro-electro-mechanical resonator with high quality factor, wherein the edge of the third metal layer is etched into a bevel, the inclination angle of the edge bevel of the third metal layer is less than 30°, or the inclination angle of the edge bevel of the third metal layer is less than 15°; and the thickness of the first metal layer is greater than or equal to the thickness of the dielectric layer.
[0022] A piezoelectric driving silicon-based micro-electro-mechanical resonator with high quality factor, wherein a second metal layer is arranged between the device silicon layer and the dielectric layer, the second metal layer at least partially extends to the outside of the dielectric layer, and the second metal layer and the first metal layer at least partially meet at the outside of the dielectric layer.
[0023] A piezoelectric driving silicon-based micro-electro-mechanical resonator with high quality factor, wherein the bottom electrode layer composed of the device silicon layer, the dielectric layer and the first metal layer is an integral whole and has a single polarity.
[0024] A piezoelectric driving silicon-based micro-electro-mechanical resonator with high quality factor, wherein the top electrode layer is provided with a first electrode pin and a second electrode pin, the first electrode pin is connected to the first metal layer in the bottom electrode layer through an electrical connection hole structure, and the first electrode pin and the second electrode pin are respectively connected to two signal terminals with opposite polarities of the top electrode layer; or the first electrode pin is connected to a ground signal terminal, and the second electrode pin is connected to a signal terminal.
[0025] A piezoelectric driving silicon-based micro-electro-mechanical resonator with high quality factor, wherein the top electrode layer is provided with a first electrode pin, a second electrode pin and a third electrode pin; the first electrode pin is connected to a ground signal terminal and connected to the first metal layer in the bottom electrode layer through an electrical connection hole structure, and the second electrode pin and the third electrode pin are respectively connected to two signal terminals with opposite polarities of the top electrode layer.
[0026] A piezoelectric driving silicon-based micro-electro-mechanical resonator with high quality factor, wherein the part of the first metal layer of the bottom electrode layer above the dielectric layer is patterned to form a first region of the bottom electrode layer; and the device silicon layer, the dielectric layer with the edge wrapped by the first metal layer and the device silicon layer, and the part of the first metal layer in electrical contact with the device silicon layer, form a second region of the bottom electrode layer.
[0027] A piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor, wherein a first region of the bottom electrode layer is connected to a signal terminal, and a second region of the bottom electrode layer is grounded to a signal terminal or a signal terminal with the opposite polarity to the first region of the bottom electrode layer.
[0028] A piezoelectric-driven silicon-based microelectromechanical resonator with a high quality factor, wherein the first region of the bottom electrode layer includes a positive electrode region and a negative electrode region, which are respectively connected to two signal terminals with opposite polarities, and the second region of the bottom electrode layer is grounded to the signal terminal.
[0029] A piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor, wherein the dielectric layer is made of silicon dioxide, fluorine-doped silicon dioxide, silicon nitride, silicon oxynitride, aluminum nitride, doped aluminum nitride, aluminum oxide, titanium oxide, or tantalum pentoxide, and the dielectric layer is a single-layer structure or a multilayer structure combining the above-mentioned different dielectric materials.
[0030] A piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor, wherein the resistivity of the silicon layer of the device is less than 8. or less than 1 or less than 0.8 .
[0031] A piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor, wherein the silicon layer of the device is heavily doped silicon, and the doping element is one or more of boron, phosphorus, and arsenic, and the doping concentration of the doping element is greater than 10 in at least a portion of the silicon layer or of a certain thickness. 19 cm -3 The above; or greater than 10 20 cm -3 above.
[0032] A piezoelectric-driven silicon-based microelectromechanical resonator with a high quality factor, wherein the piezoelectric material of the piezoelectric layer is aluminum nitride, doped aluminum nitride, zinc oxide, PZT, lithium niobate, or lithium tantalate.
[0033] A piezoelectric-driven silicon-based microelectromechanical resonator with a high quality factor, wherein a first bonding layer and / or a second bonding layer are disposed between the substrate silicon layer and the resonant film layer and adhered to the surface of the substrate silicon layer having a cavity; the material of the first bonding layer and the second bonding layer is silicon dioxide.
[0034] A piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor, wherein the top electrode layer is made of a metal, such as molybdenum, aluminum, copper, platinum, tantalum, tungsten, palladium, ruthenium, gold, titanium, chromium, or their alloys or composite layers; or the top electrode layer is made of doped polycrystalline silicon, with boron, phosphorus, or arsenic as the doping element, and a doping concentration greater than 10. 19 cm -3 .
[0035] (III) Beneficial Effects: The present invention provides a piezoelectric-driven silicon-based microelectromechanical resonator with a high quality factor. A bottom electrode layer with a single polarity is formed by wrapping a dielectric layer with a first metal layer and a device silicon layer. A multi-polarity bottom electrode layer is formed by partially wrapping the dielectric layer with the edges of the first metal layer and the device silicon layer. By covering the dielectric layer with the first metal layer and the structure of wrapping or partially wrapping the dielectric layer with the first metal layer, the piezoelectric-driven silicon-based microelectromechanical resonator of the present invention can obtain a high quality factor Q value and low electrical loss, i.e., low series resonant impedance, across the entire temperature range. Attached Figure Description
[0036] Figure 1(a) is a schematic diagram of the stacked structure of the bonding layer with the attached vibration film in the prior art piezoelectric driven silicon-based microelectromechanical resonator; Figure 1(b) is a schematic diagram of the stacked structure of the bonding layer with a cavity attached to the substrate silicon layer in the prior art piezoelectric driven silicon-based microelectromechanical resonator; Figure 2 This is a schematic diagram of the stacked structure of a silicon-based microelectromechanical resonator driven by piezoelectricity, which has a first metal layer between the silicon layer and the piezoelectric layer. Figure 3(a) is a schematic diagram of the stacked structure in the first preferred embodiment of the present invention, in which the boundary of the dielectric layer is located within the effective vibration region; Figure 3(b) is a schematic diagram of the stacked structure in the first preferred embodiment of the present invention, showing the boundary of the dielectric layer located between the effective vibration region and the region corresponding to the inner edge of the cavity. Figure 3(c) is a schematic diagram of the stacked structure of the region above the outer edge of the cavity corresponding to the boundary of the dielectric layer in the first preferred embodiment of the present invention; Figure 3(d) is a schematic diagram of the stacked structure of the first metal layer above the dielectric layer of the present invention, which is patterned to cover part of the device silicon layer; Figure 4 This is a schematic diagram of the stacked structure of the device silicon layer and dielectric layer and the device silicon layer and metal layer in the first preferred embodiment of the present invention; Figure 5(a) is a top view of a piezoelectrically driven silicon-based microelectromechanical resonator using the single polarity bottom electrode layer structure of the present invention in a first-order width expansion mode. Figure 5(b) is a top view of a piezoelectrically driven silicon-based microelectromechanical resonator with a tuning fork-shaped out-of-plane bending mode using the single-electrode bottom electrode layer structure of the present invention. Figure 6(a) is a schematic diagram of a stacked structure with two metal layers in the second preferred embodiment of the present invention; Figure 6(b) is a schematic diagram of the stacked structure between the device silicon layer and the dielectric layer and between the device silicon layer and the second metal layer in the second preferred embodiment of the present invention; Figure 7(a) is a schematic diagram of a stacked structure with two dielectric layers in the third preferred embodiment of the present invention; Figure 7(b) is a schematic diagram of the stacked structure of the device silicon layer and the first dielectric layer and the device silicon layer and the metal layer with a second metal layer in the third preferred embodiment of the present invention; Figure 8(a) is a top view of the top electrode layer pattern of a piezoelectrically driven silicon-based microelectromechanical resonator with a high-order width expansion mode in the fourth preferred embodiment of the present invention; Figure 8(b) is a top view of the bottom electrode layer pattern of a piezoelectrically driven silicon-based microelectromechanical resonator with a high-order width expansion mode in the fourth preferred embodiment of the present invention; Figure 8(c) is a schematic diagram of the stacked structure of the piezoelectrically driven silicon-based microelectromechanical resonator in the high-order width expansion mode along the cross section of BB' in the fourth preferred embodiment of the present invention. Figure 9(a) is a top view of the top electrode layer pattern of a piezoelectrically driven silicon-based microelectromechanical resonator with a high-order width expansion mode in the fifth preferred embodiment of the present invention; Figure 9(b) is a top view of the bottom electrode layer pattern of a piezoelectrically driven silicon-based microelectromechanical resonator with a high-order width expansion mode in the fifth preferred embodiment of the present invention; Figure 9(c) is a schematic diagram of the stacked structure of the piezoelectrically driven silicon-based microelectromechanical resonator in the high-order width expansion mode along the cross section of CC' in the fifth preferred embodiment of the present invention.
[0037] Icon labels: 101 - Substrate silicon layer, 102 - Cavity, 103 - First bonding layer; 201-Device silicon layer, 202-Piezoelectric layer, 203-Top electrode layer, 204-Second bonding layer, 205-First metal layer, 206-Dielectric layer, 206-1-First dielectric layer, 206-2-Second dielectric layer, 207-Second metal layer, 208-Third metal layer; 301 - Groove, 302 - Electrical connection hole; 401 - First electrode pin, 402 - Second electrode pin, 403 - Third electrode pin. Detailed Implementation
[0038] The present invention will be further described in detail below with reference to preferred embodiments. More details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.
[0039] The accompanying drawings are schematic diagrams of embodiments of the present invention. It should be noted that these drawings are for illustrative purposes only and are not drawn to scale, and should not be construed as limiting the actual scope of protection of the present invention.
[0040] The present invention provides a piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor. A first preferred embodiment, as shown in Figures 3(a), 3(b), 3(c), and 3(d), includes a resonant film layer disposed on a substrate silicon layer 101. The resonant film layer includes a bottom electrode layer. The bottom electrode layer includes, from bottom to top, a device silicon layer 201, a dielectric layer 206, and a first metal layer 205. The first metal layer 205 and the device silicon layer 201 surround the edge of the dielectric layer 206.
[0041] The piezoelectric-driven silicon-based microelectromechanical resonator preferably includes a substrate silicon layer 101 having a cavity 102, and the resonant film layer covers the cavity 102.
[0042] In this invention, a dielectric layer 206 is disposed on the silicon layer 201 of the device, and the dielectric layer 206 is covered by the first metal layer 205. This structure enables the piezoelectrically driven silicon-based microelectromechanical resonator to obtain a high quality factor Q value and low electrical loss, i.e., low series resonant impedance, across the entire temperature range.
[0043] This invention relates to a piezoelectric-driven silicon-based microelectromechanical resonator with a high quality factor. Preferably, the resonant film layer, from the substrate silicon layer 101 side upwards, includes a device silicon layer 201, a dielectric layer 206, a first metal layer 205, a piezoelectric layer 202, and a top electrode layer 203. The device silicon layer 201 is the resonant core of the piezoelectric-driven silicon-based microelectromechanical resonator, and the piezoelectric layer 202 drives the device silicon layer 201 to vibrate.
[0044] In the piezoelectric-driven silicon-based microelectromechanical resonator of the present invention, the corresponding region of the cavity 102 on the vibrating diaphragm is the effective vibration region of the vibrating diaphragm, and the dielectric layer 206 is located within the effective vibration region; or, the dielectric layer 206 is located both inside and outside the effective vibration region; or the dielectric layer 206 coincides with the effective vibration region.
[0045] The vibration diaphragm layer of this invention preferably has grooves 301. Some vibration modes require free boundaries at the edges. The grooves 301 are used to define the boundary conditions of the effective vibration region on the vibration diaphragm layer. The grooves 301 penetrate the vibration diaphragm layer above the cavity 102 in the corresponding region. This invention defines the effective vibration region on the vibration diaphragm layer defined by the grooves 301 as the first region, the portion of the corresponding region of the cavity 102 on the vibration diaphragm layer other than the first region as the second region, and the portion of the vibration diaphragm layer other than the first and second regions as the third region. This invention defines the position closer to the center of the piezoelectric-driven silicon-based microelectromechanical resonator as the inner side, and the position farther from the center of the piezoelectric-driven silicon-based microelectromechanical resonator as the outer side.
[0046] The dielectric layer 206 of the present invention has the following three embodiments: In the first preferred embodiment of the positioning of the medium layer 206, the medium layer 206 is located in a first region, that is, inside the edge of the cavity 102, within the boundary of the effective vibration region defined by the groove 301, as shown in Figure 3(a).
[0047] A second preferred embodiment of the positioning of the dielectric layer 206: the dielectric layer 206 is located in the first region and the second region, as shown in Figure 3(b).
[0048] A third preferred embodiment of the positioning of the dielectric layer 206: the dielectric layer 206 is located in the first region, the second region and the third region, as shown in Figure 3(c).
[0049] In the vibrating diaphragm layer of the present invention, a patterned dielectric layer 206 exists between the first metal layer 205 and the device silicon layer 201. The first metal layer 205 encapsulates the dielectric layer 206 and simultaneously covers the surface of the device silicon layer 201. That is, on the outer edge of the dielectric layer 206, the first metal layer 205 directly covers the surface of the device silicon layer 201.
[0050] In the vibration diaphragm layer of the present invention, the first metal layer 205 can be patterned so that it only covers part of the surface of the silicon layer 201 of the device, as shown in FIG3(d).
[0051] When etching to form the trench 301, the end faces of each material layer can be flush or uneven, and this invention does not impose any restrictions.
[0052] Preferred embodiments of the present invention include, for example, Figure 4As shown, a second metal layer 207 can also be disposed on the surface of the silicon layer 201 of the device. The second metal layer 207 can adhere to the silicon layer 201 of the device. The first metal layer 205 encapsulates the dielectric layer 206 and covers the surface of the second metal layer 207. Preferably, the second metal layer 207 can be patterned so that it only covers a portion of the surface of the silicon layer 201 of the device. In the piezoelectric driven silicon-based microelectromechanical resonator of the present invention, there is a second metal layer 207 between the silicon layer 201 of the device and the first metal layer 205. The second metal layer 207 can serve as a stop layer when etching the dielectric layer 206, thereby avoiding etching of the surface of the silicon layer 201 of the device, which would affect the adhesion between the first metal layer 205 and the silicon layer 201 of the device, as well as the lattice orientation of the subsequently grown piezoelectric layer 202. On the other hand, the second metal layer 207 can further reduce the series equivalent resistance of the bottom electrode layer.
[0053] Preferably, one or more dielectric layers may be disposed below the silicon layer 201 of the device and / or above the top electrode layer 203 to achieve an auxiliary temperature compensation effect, or as a passivation layer to protect the electrode from oxidation and thus improve device reliability.
[0054] Preferably, the cavity 102 can be a single cavity or an array of multiple sub-cavities. Its depth can be set according to the vibration amplitude of the piezoelectric-driven silicon-based microelectromechanical resonator. For example, the depth of the cavity is greater than 10 μm, greater than 25 μm, or greater than 50 μm.
[0055] Preferably, the silicon layer 201 of the device can be monocrystalline silicon or polycrystalline silicon. To reduce the equivalent resistance of the silicon layer, the resistivity of the silicon layer 201 is less than 8. Preferably, its resistivity is less than 1. Furthermore, less than 0.8 .
[0056] The silicon layer 201 of the device is heavily doped silicon, and the doping element can be one or more of boron, phosphorus, arsenic, etc. The doping concentration of the doping element is greater than 10 in at least a portion or thickness of the device silicon layer. 19 cm -3 When the doping element is boron, the resistivity of the silicon layer of the device is less than 8. When the doping element is phosphorus or arsenic, the resistivity of the silicon layer of the device is less than 5%. More preferably, the doping concentration of the dopant element is greater than 10. 20 cm -3 When the doping element is boron, the resistivity of the silicon layer of the device is less than 1. When the doping element is phosphorus or arsenic, the resistivity of the silicon layer of the device is less than 0.8. To improve the temperature coefficient of device frequency, phosphorus or arsenic are preferred as dopants.
[0057] Preferably, the piezoelectric material of the piezoelectric layer 202 can be a single-crystal piezoelectric material or a polycrystalline piezoelectric material. The piezoelectric material of the piezoelectric layer 202 can be: aluminum nitride, doped aluminum nitride, zinc oxide, PZT, lithium niobate, lithium tantalate, etc.; the doping element of the doped aluminum nitride can be a rare earth element, such as scandium Sc, yttrium Y, etc., or a group II / XII element, such as Ca, Mg, Sr, Zn, etc., or a group IV / V element, such as Ti, Zr, Hf, etc.
[0058] Preferably, the material of the top electrode layer 203 in this invention can be a metal, such as molybdenum (Mo), aluminum (Al), copper (Cu), platinum (Pt), tantalum (Ta), tungsten (W), palladium (Pd), ruthenium (Ru), gold (Au), titanium (Ti), chromium (Cr), etc., or their alloys or composite layers. The material of the top electrode layer 203 can also be doped polycrystalline silicon, and the doping element can be boron (B), phosphorus (P), arsenic (As), etc., with a doping concentration generally greater than 10. 19 cm -3 In summary, the higher the doping concentration, the lower the sheet resistance and electrical loss of the polycrystalline silicon electrode.
[0059] Preferably, the first metal layer 205 and the second metal layer 207 can be single-layer or multi-layer metal materials, such as molybdenum (Mo), aluminum (Al), copper (Cu), platinum (Pt), tantalum (Ta), tungsten (W), palladium (Pd), ruthenium (Ru), gold (Au), titanium (Ti), chromium (Cr), and their alloys or composite layers. They may also include at least one adhesion layer, such as Ti, TiW, Cr, etc. The first metal layer 205, the second metal layer 207 and the top electrode layer 203 can be made of the same material, for example, molybdenum (Mo) can be selected simultaneously, or different materials can be selected.
[0060] Preferably, the material of the dielectric layer 206 in this invention is generally silicon dioxide, fluorine-doped silicon dioxide, silicon nitride, silicon oxynitride, aluminum nitride, doped aluminum nitride, aluminum oxide, titanium oxide, tantalum pentoxide, etc. The dielectric layer 206 can be a single layer or a combination of multiple layers of different dielectric materials.
[0061] Preferably, the edge of the dielectric layer 206 needs to be etched into a bevel to facilitate the growth of the electrode and piezoelectric layer material above it, preventing breakage at this location. The bevel angle of the edge of the dielectric layer 206 is less than 80°; more preferably, the bevel angle of the edge of the dielectric layer 206 is less than 60°; even more preferably, the bevel angle of the edge of the dielectric layer 206 is less than 30°. The thicker the dielectric layer 206, the smaller the bevel angle of its edge should be. Preferably, the total thickness of the dielectric layer 206 is between 5 nm and 500 nm.
[0062] Preferably, a third bonding layer 103 is disposed between the substrate silicon layer 101 and the vibrating film layer, adhering to the surface of the substrate silicon layer 101 having a cavity 102, or a second bonding layer 204 is adhering to the surface of the vibrating film layer. The first bonding layer 103 and the second bonding layer 204 are made of silicon dioxide. Preferably, the first bonding layer 103 or the second bonding layer 204 also serves as an insulating layer between the vibrating film layer and the substrate silicon layer 101.
[0063] In a preferred embodiment of the piezoelectric-driven silicon-based microelectromechanical resonator of the present invention, the bottom electrode layer composed of the silicon layer 201, the dielectric layer 206 and the first metal layer 205 is a whole and has a single electrode polarity.
[0064] A preferred embodiment of the piezoelectric-driven silicon-based microelectromechanical resonator of the present invention has a single polarity in its bottom electrode layer, as shown in Figure 5(a). This is a top view of the structure of a first-order width-extensional mode piezoelectric-driven silicon-based microelectromechanical resonator that can employ a single polarity bottom electrode layer. A first metal layer, a device silicon layer, and a dielectric layer 206 enclosed by the first metal layer and the device silicon layer constitute the bottom electrode layer of this embodiment, which has a single polarity. The top electrode layer is provided with a first electrode pin 401 and a second electrode pin 402. The first electrode pin 401 is a pin connected to the bottom electrode layer, and the second electrode pin 402 is a pin connected to the top electrode layer. When the piezoelectric-driven silicon-based microelectromechanical resonator is operating, the first electrode pin 401 is grounded to the signal terminal, and the second electrode pin 402 is connected to the signal terminal, thereby forming a single-port device.
[0065] Another preferred embodiment of the piezoelectric-driven silicon-based microelectromechanical resonator of the present invention has a single polarity in its bottom electrode layer, as shown in FIG5(b), which is a top view of a tuning fork-type out-of-plane flexural mode piezoelectric-driven silicon-based microelectromechanical resonator that can adopt the above-described bottom electrode layer structure. The device silicon layer, the first metal layer, and the dielectric layer 206 enclosed by the first metal layer and the device silicon layer constitute the bottom electrode layer of this embodiment, which has a single polarity. The top electrode layer is provided with a first electrode pin 401, a second electrode pin 402, and a third electrode pin 403. The first electrode pin 401 is a pin connected to the bottom electrode layer, and the second electrode pin 402 and the third electrode pin 403 are pins connected to the top electrode layer 203. When the piezoelectric-driven silicon-based microelectromechanical resonator is working, the first electrode pin 401 is grounded to the signal terminal, and the second electrode pin 402 and the third electrode pin 403 are respectively connected to two signal terminals with opposite polarities of the top electrode layer 203, thereby forming a two-port device.
[0066] A second preferred embodiment of the piezoelectrically driven silicon-based microelectromechanical resonator of the present invention, as shown in FIG6(a), includes a substrate silicon layer 101 having a cavity 102, and a resonant film layer disposed on the substrate silicon layer 101 covering the cavity 102. The resonant film layer has a trench 301 penetrating the cavity 102 in a corresponding region of the cavity 102. The resonant film layer, from the substrate silicon layer 101 side upwards, sequentially includes a device silicon layer 201, a dielectric layer 206, a third metal layer 208, a first metal layer 205, a piezoelectric layer 202, and a top electrode layer 203. The first metal layer 205 wraps around the dielectric layer 206 through the third metal layer 208, and simultaneously covers the device silicon layer 201. The third metal layer 208 is located above the dielectric layer 206 and does not directly contact the surface of the device silicon layer 201; the dielectric layer 206 and the third metal layer 208 are stacked vertically.
[0067] The edge of the third metal layer 208 needs to be etched into a bevel to facilitate the growth of the piezoelectric layer material above it, so as not to break at this location.
[0068] Preferably, the bevel angle of the edge of the third metal layer 208 is less than 30°; more preferably, the bevel angle of the edge of the third metal layer 208 is less than 15°. In this case, the dielectric layer 206 also serves as a stop layer for etching the third metal layer 208, thereby avoiding damage to the silicon layer 201 of the device.
[0069] To ensure that the first metal layer 205 effectively covers the edge sidewalls of the dielectric layer 206, preferably, the thickness of the first metal layer 205 is greater than or equal to the thickness of the dielectric layer 206.
[0070] Preferably, the third metal layer 208 and the first metal layer 205 can be single-layer or multi-layer metal materials, such as molybdenum (Mo), aluminum (Al), copper (Cu), platinum (Pt), tantalum (Ta), tungsten (W), palladium (Pd), ruthenium (Ru), gold (Au), titanium (Ti), chromium (Cr), and their alloys or composite layers. They may also include at least one adhesion layer, such as Ti, TiW, or Cr. The third metal layer 208 and the first metal layer 205 can be made of the same material or different materials.
[0071] In this embodiment, among a set of optional materials, the dielectric layer 206 can be made of aluminum nitride, the third metal layer 208, the first metal layer 205 and the top electrode layer 203 are all made of Mo or W, and the piezoelectric layer 202 is made of aluminum nitride or doped aluminum nitride.
[0072] Preferably, a second metal layer 207, which is attached to the silicon layer 201, can also be disposed on the upper surface of the silicon layer 201, as shown in FIG6(b). The second metal layer 207 is located between the dielectric layer 206 and the silicon layer 201, while the first metal layer 205 wraps around the dielectric layer 206 and covers the surface of the second metal layer 207. In this case, the second metal layer 207 can further reduce the series equivalent resistance value of the bottom electrode layer.
[0073] As shown in Figures 6(a) and 6(b), the present invention further includes an electrical connection hole 302 penetrating the piezoelectric layer 202. One end of the electrical connection hole 302 is connected to the first metal layer 205, and the other end is connected to an electrode pin located on the top electrode layer 203, thereby facilitating the application of electrical signals. The present invention also includes a second bonding layer 204 disposed between the substrate silicon layer 101 and the resonant film layer, and attached to the surface of the resonant film layer.
[0074] In a second preferred embodiment of the piezoelectrically driven silicon-based microelectromechanical resonator with high quality factor of the present invention, the first metal layer 205, and the third metal layer 208 and dielectric layer 206 of the upper and lower stacked layers wrapped by the first metal layer 205 and the device silicon layer 201 constitute the bottom electrode layer of the present invention, and the bottom electrode layer has a single polarity.
[0075] A third preferred embodiment of the piezoelectric-driven silicon-based microelectromechanical resonator with a high quality factor of the present invention is shown in Figures 7(a) and 7(b). The piezoelectric-driven silicon-based microelectromechanical resonator with a high quality factor of the present invention includes a substrate silicon layer 101 having a cavity 102, and a resonant film layer disposed on the substrate silicon layer 101 covering the cavity 102. The resonant film layer, from one side of the substrate silicon layer 101 upwards, includes a device silicon layer 201, a dielectric layer 206, a first metal layer 205, a piezoelectric layer 202, and a top electrode layer 203, wherein the dielectric layer 206 is wrapped by the device silicon layer 201 and the first metal layer 205. Preferably, the dielectric layer 206 includes a first dielectric layer 206-1 and a second dielectric layer 206-2 stacked vertically, wherein the first metal layer 205 covers the surface of the second dielectric layer 206-2, the side surface of the first dielectric layer 206-1, and the surface of the device silicon layer 201 not covered by the first dielectric layer 206-1.
[0076] In the third preferred embodiment, the piezoelectric-driven silicon-based microelectromechanical resonator further includes an electrical connection hole 302 penetrating the piezoelectric layer 202. One end of the electrical connection hole 302 is connected to the first metal layer 205, and the other end is connected to an electrode pin located on the top electrode layer 203, thereby facilitating the application of electrical signals. The invention also includes a second bonding layer 204 disposed between the substrate silicon layer 101 and the resonant film layer, and attached to the surface of the resonant film layer.
[0077] In the third preferred embodiment, the first metal layer 205, the first dielectric layer 206-1 and the second dielectric layer 206-2 which are wrapped by the first metal layer 205 and the device silicon layer 201 constitute the bottom electrode layer of the present invention, and the bottom electrode layer has a single electrode property.
[0078] In the third preferred embodiment, the thickness of the second dielectric layer 206-2 is typically greater than the thickness of the first dielectric layer 206-1.
[0079] In the third preferred embodiment, the edge of the second dielectric layer 206-2 needs to be etched into a bevel to facilitate the growth of the piezoelectric layer material above it, preventing breakage at this location. Preferably, the bevel angle of the edge of the second dielectric layer 206-2 is less than 30°; more preferably, the bevel angle of the edge of the second dielectric layer 206-2 is less than 15°. In this case, the first dielectric layer 206-1 also serves as a stop layer for etching the second dielectric layer 206-2, thereby avoiding damage to the device silicon layer 201.
[0080] In the third preferred embodiment, the material of the first dielectric layer 206-1 can be aluminum nitride, the material of the second dielectric layer 206-2 can be silicon dioxide, the material of the first metal layer 205 and the top electrode layer 203 are both Mo or W, and the material of the piezoelectric layer 202 is aluminum nitride or doped aluminum nitride.
[0081] In the third preferred embodiment, the piezoelectric-driven silicon-based microelectromechanical resonator further includes a second metal layer 207 bonded to the surface of the silicon layer 201 of the device, as shown in FIG7(b). The second metal layer 207 can further reduce the series equivalent resistance of the bottom electrode layer. The second metal layer 207 and the first metal layer 205 encapsulate the dielectric layer 206, such that the upper surface of the second metal layer 207 is bonded to the lower surface of the first dielectric layer 206-1 and a portion of the lower surface of the silicon layer 201 of the device.
[0082] In the third preferred embodiment, the first metal layer 205 and the dielectric layer 206 wrapped by the first metal layer 205 and the device silicon layer 201, including the first dielectric layer 206-1 and the second dielectric layer 206-2, constitute the bottom electrode layer of the present invention, and the bottom electrode layer has a single polarity.
[0083] The fourth preferred embodiment of the piezoelectrically driven silicon-based microelectromechanical resonator of the present invention, as shown in Figures 8(a), 8(b), and 8(c), is a top view of a high-order width-extensional mode piezoelectrically driven silicon-based microelectromechanical resonator. Figure 8(a) shows a top view of the patterned top electrode layer 203, and Figure 8(b) shows a top view of the patterned bottom electrode layer. The shapes of the patterned bottom electrode layer and top electrode layer 203 are etched as needed and can be the same or different; no limitation is made here.
[0084] A fourth preferred embodiment of the piezoelectric-driven silicon-based microelectromechanical resonator is shown in Figure 8(c) in a longitudinal cross-sectional view along the B-B' direction in a top view. The bottom electrode layer includes, from bottom to top, a device silicon layer 201, a dielectric layer 206, and a first metal layer 205. The patterned first metal layer 205 has a hollowed-out portion, thus the hollowed-out first metal layer 205 and the device silicon layer 201 enclose the dielectric layer 206, meaning the first metal layer 205 and the device silicon layer 201 partially enclose the dielectric layer. The patterned first metal layer 205 extends around the edge of the dielectric layer 206 to the surface of the device silicon layer 201.
[0085] In a preferred embodiment, the first metal layer 205 extends around the edge of the dielectric layer 206 to the surface of the device silicon layer 201, and the first metal layer 205 and the device silicon layer 201 form a semi-enclosed structure around the edge of the dielectric layer.
[0086] In a preferred embodiment, the patterned first metal layer 205 in the bottom electrode layer may include two electrode regions. The portion of the first metal layer 205 above the dielectric layer 206 is patterned to form the first region of the bottom electrode layer. The device silicon layer 201, the dielectric layer 206 whose edges are wrapped by the first metal layer 205 and the device silicon layer 201, and the portion of the first metal layer 205 that is in contact with the device silicon layer 201 constitute the second region of the bottom electrode layer.
[0087] In this preferred embodiment, the first region of the bottom electrode layer can have a single polarity or a multi-polarity region.
[0088] When the first region of the bottom electrode layer has a single polarity, the first region of the bottom electrode layer is connected to a signal terminal via a signal pin; the second region of the bottom electrode layer is connected to a ground terminal via a signal pin, or the second region of the bottom electrode layer is electrically connected to the first region of the bottom electrode layer.
[0089] When the first region of the bottom electrode layer has a multipolar region, the first region of the bottom electrode layer may include two electrode regions: a positive electrode region and a negative electrode region.
[0090] In the fourth preferred embodiment, when the first region of the bottom electrode layer has a multi-polar region, the present invention further includes an electrical connection hole 302 penetrating the piezoelectric layer 202. One end of the electrical connection hole 302 is connected to the first metal layer 205, and the other end is connected to an electrode pin located on the top electrode layer 203. The top electrode layer 203 is provided with a first electrode pin 401 connected to a ground signal terminal, a second electrode pin 402 configured as a positive signal pin, and a third electrode pin 403 configured as a negative signal pin. The polarities of the second electrode pin 402 and the third electrode pin 403 can be interchanged. The second electrode pin 402 is connected to the negative electrode region of the bottom electrode layer through the electrical connection hole 302. The third electrode pin 403 is connected to the positive electrode region of the bottom electrode layer through another electrical connection hole 302. Both the positive and negative electrode regions of the first metal layer 205 are located above the dielectric layer 206 and are not connected to the device silicon layer 201. Neither the positive nor negative electrode regions of the first metal layer 205 enclose the edge of the dielectric layer 206. The top electrode layer 203 and the bottom electrode layer 201 of the present invention are connected to electrodes with opposite polarities, forming an electric field in the thickness direction.
[0091] The second region of the bottom electrode layer is connected to the first electrode pin 401 through another via 302. The second region of the bottom electrode layer includes a device silicon layer 201, a dielectric layer 206 whose edges are wrapped by a first metal layer 205 and the device silicon layer 201, and a portion of the first metal layer 205 that is in electrical contact with the device silicon layer 201.
[0092] A top view of the top electrode layer 203 of a piezoelectrically driven silicon-based microelectromechanical resonator in a fifth preferred embodiment of the present invention is shown in Figure 9(a), and a top view of the bottom electrode layer is shown in Figure 9(b). A longitudinal cross-sectional view along CC' of Figures 9(a) and 9(b) is shown in Figure 9(c). As shown in Figure 9(c), the difference between the fifth preferred embodiment and the fourth preferred embodiment is that the first signal pin 401 is not provided on the diaphragm layer, and the second region of the bottom electrode layer is electrically connected to the positive or negative region of the bottom electrode layer through a second signal pin 402 or a third signal pin 403.
[0093] The piezoelectrically driven silicon-based microelectromechanical resonator with high quality factor proposed in this invention can have various planar structures for the vibrating diaphragm, and the corresponding electrode arrangements also vary. The vibrating diaphragm can have various vibration modes, such as in-plane flexural mode, out-of-plane flexural mode, width extensional mode (WE mode), length extensional mode (LE mode), Lamé mode, etc., but is not limited to these vibration modes.
[0094] The piezoelectrically driven silicon-based microelectromechanical resonator with high quality factor proposed in this invention can generally cover a resonant frequency range from tens of kHz to hundreds of MHz, but is not limited to this. The piezoelectrically driven silicon-based microelectromechanical resonator with high quality factor proposed in this invention can also be used as a component of sensors, such as pressure sensors, accelerometers, gyroscopes, micromirrors, and piezoelectric transducers (PMUTs).
[0095] In the piezoelectrically driven silicon-based microelectromechanical resonator with high quality factor provided by the present invention, a bottom electrode layer with unipolarity is formed by wrapping a dielectric layer 206 with a first metal layer 205 and a device silicon layer 201; a bottom electrode layer with multipolarity is formed by partially wrapping the dielectric layer 206 with the edges of the first metal layer 205 and the device silicon layer 201; by covering the dielectric layer 206 with the first metal layer 205 and the structure of the first metal layer wrapping or partially wrapping the dielectric layer 206, the piezoelectrically driven silicon-based microelectromechanical resonator of the present invention obtains a high quality factor Q value and low electrical loss, i.e., low series resonant impedance, across the entire temperature range.
[0096] The above description illustrates preferred embodiments of the present invention and helps those skilled in the art to more fully understand the technical solution of the present invention. However, these embodiments are merely illustrative and should not be construed as limiting the specific implementation of the present invention to these embodiments. For those skilled in the art, several simple deductions and modifications can be made without departing from the inventive concept, and all such modifications should be considered within the protection scope of the present invention.
Claims
1. A piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor, comprising a substrate silicon layer having a cavity and a resonant film layer disposed on the substrate silicon layer covering the cavity, characterized in that, The vibrating diaphragm layer comprises, from bottom to top, a bottom electrode layer, a piezoelectric layer, and a top electrode layer; the bottom electrode layer comprises, from bottom to top, a device silicon layer, a dielectric layer, and a first metal layer; the dielectric layer covers a portion of the device silicon layer, and the first metal layer covers at least a portion of the dielectric layer, and the first metal layer extends at least partially to the outside of the dielectric layer and covers at least a portion of the device silicon layer.
2. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 1, characterized in that, The dielectric layer is completely encapsulated by the device's silicon layer and the first metal layer.
3. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 1, characterized in that, The corresponding area of the cavity on the vibrating diaphragm is the effective vibration area. The edge of the medium layer is located within the effective vibration area, or outside the effective vibration area, or coincides with the effective vibration area.
4. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 3, characterized in that, The vibration diaphragm layer has grooves in the corresponding area of the cavity to define the boundary conditions of the effective vibration area, and the grooves penetrate the vibration diaphragm layer.
5. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 4, characterized in that, The edge of the medium layer is located within the boundary of the effective vibration area defined by the groove; or the edge of the medium layer is located outside the boundary of the effective vibration area defined by the groove, but still inside the area corresponding to the edge of the cavity; or the edge of the medium layer extends to the area corresponding to the outer side of the cavity.
6. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 1, characterized in that, The edge of the dielectric layer is etched into a bevel; the bevel angle of the edge of the dielectric layer is less than 80°, or the bevel angle of the edge of the dielectric layer is less than 60°, or the bevel angle of the edge of the dielectric layer is less than 30°.
7. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 6, characterized in that, The thickness of the dielectric layer is between 5 nm and 500 nm.
8. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 1, characterized in that, The dielectric layer includes a first dielectric layer and a second dielectric layer stacked on top of each other, the second dielectric layer completely covering the upper surface of the first dielectric layer; the first metal layer covers the surface of the second dielectric layer, the side surface of the first dielectric layer, and the surface of the device silicon layer not covered by the first dielectric layer.
9. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 8, characterized in that, The edge of the second dielectric layer is etched into a bevel; the bevel angle of the edge of the second dielectric layer is less than 30°, or the bevel angle of the edge of the second dielectric layer is less than 15°.
10. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 8, characterized in that, The thickness of the second dielectric layer is greater than the thickness of the first dielectric layer.
11. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 1, characterized in that, A third metal layer is disposed between the first metal layer and the dielectric layer. The third metal layer completely covers the upper surface of the dielectric layer. The first metal layer covers the surface of the third metal layer, the side surface of the dielectric layer, and the surface of the device silicon layer not covered by the first dielectric layer.
12. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 11, characterized in that, The edge of the third metal layer is etched into a bevel, and the bevel angle of the edge of the third metal layer is less than 30° or less than 15°; the thickness of the first metal layer is greater than or equal to the thickness of the dielectric layer.
13. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 1, characterized in that, A second metal layer is disposed between the silicon layer and the dielectric layer of the device. The second metal layer extends at least partially to the outside of the dielectric layer, and the second metal layer and the first metal layer are at least partially connected on the outside of the dielectric layer.
14. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 2, characterized in that, The bottom electrode layer, composed of the silicon layer, dielectric layer, and first metal layer of the device, is a single unit and has a single electrode property.
15. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 14, characterized in that, The top electrode layer is provided with a first electrode pin and a second electrode pin. The first electrode pin is connected to the first metal layer in the bottom electrode layer through an electrical connection hole structure. The first electrode pin and the second electrode pin are respectively connected to two signal terminals with opposite polarities of the top electrode layer; or the first electrode pin is grounded to the signal terminal and the second electrode pin is connected to the signal terminal.
16. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 14, characterized in that, The top electrode layer is provided with a first electrode pin, a second electrode pin, and a third electrode pin; the first electrode pin is connected to the ground signal terminal and is connected to the first metal layer in the bottom electrode layer through an electrical connection hole structure; the second electrode pin and the third electrode pin are respectively connected to two signal terminals with opposite polarities of the top electrode layer.
17. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 1, characterized in that, The portion of the first metal layer of the bottom electrode layer located above the dielectric layer is patterned to form the first region of the bottom electrode layer; the device silicon layer, the dielectric layer whose edges are wrapped by the first metal layer and the device silicon layer, and the portion of the first metal layer that is electrically in contact with the device silicon layer constitute the second region of the bottom electrode layer.
18. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 17, characterized in that, The first region of the bottom electrode layer is connected to a signal terminal, and the second region of the bottom electrode layer is connected to a ground signal terminal or a signal terminal with the opposite polarity to the first region of the bottom electrode layer.
19. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 17, characterized in that, The first region of the bottom electrode layer includes a positive electrode region and a negative electrode region, which are respectively connected to two signal terminals with opposite polarities, and the second region of the bottom electrode layer is grounded to the signal terminal.
20. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 1, characterized in that, The dielectric layer is made of silicon dioxide, fluorine-doped silicon dioxide, silicon nitride, silicon oxynitride, aluminum nitride, doped aluminum nitride, aluminum oxide, titanium oxide, or tantalum pentoxide. The dielectric layer is a single-layer structure or a multilayer structure composed of the above-mentioned different dielectric materials.
21. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 1, characterized in that, The resistivity of the silicon layer of the device is less than 8. or less than 1 or less than 0.8 .
22. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 21, characterized in that, The silicon layer of the device is heavily doped silicon, and the doping element is one or more of boron, phosphorus, and arsenic. At least a portion of the silicon layer or a certain thickness contains a doping concentration of the doping element greater than 10%. 19 cm -3 The above; or greater than 10 20 cm -3 above.
23. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 1, characterized in that, The piezoelectric material of the piezoelectric layer is aluminum nitride, doped aluminum nitride, zinc oxide, PZT, lithium niobate, or lithium tantalate.
24. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 1, characterized in that, A first bonding layer and / or a second bonding layer are disposed between the substrate silicon layer and the vibrating film layer, which are attached to the surface of the substrate silicon layer having a cavity; the material of the first bonding layer and the second bonding layer is silicon dioxide.
25. The piezoelectrically driven silicon-based microelectromechanical resonator with a high quality factor according to claim 1, characterized in that, The top electrode layer is made of a metal, such as molybdenum, aluminum, copper, platinum, tantalum, tungsten, palladium, ruthenium, gold, titanium, chromium, or their alloys or composite layers; or the top electrode layer is made of doped polycrystalline silicon, with boron, phosphorus, or arsenic as the doping elements, and a doping concentration greater than 10. 19 cm -3 .