Multilayer structure for tuning and / or excitation

Abstract

The utility model belongs to the technical field of microelectronic devices, and discloses a multilayer structure for tuning and / or excitation, which comprises a substrate, a non-metal layer, a conductive two-dimensional material layer and a metal electrode, and is characterized in that the non-metal layer is arranged on the upper surface of the substrate; the conductive two-dimensional material layer is arranged on the upper surface of the non-metal layer; the metal electrode is arranged above the conductive two-dimensional material layer; the metal electrode is electrically insulated from the substrate and the non-metal material, and is electrically connected with the conductive two-dimensional material layer. The resonator is simple in structure and easy to realize, not only can be used for mechanical property tuning, but also can be used as an actuator for resonance application; besides, the structure of the utility model is a planar thin two-dimensional structure, the mass is light, and the structure and a suspended nonmetal layer in a micro-nano device are directly integrated on the same plane, so that the size of an NEMS or MEMS device can be obviously reduced, and the cost of the NEMS or MEMS system is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of microelectronic devices, and particularly relates to a multi-layer structure for tuning and / or exciting. Background Art

[0002] Micro-electromechanical systems (MEMS) and nano-electromechanical systems (NEMS) are both rapidly developing micro-miniaturized and integrated microelectronic technologies in recent years. Among them, MEMS is an integrated micro-device or system composed of components such as micro-sensors, micro-actuators, signal processing, control circuits, communication interfaces, and power supplies; NEMS is a super-small electro-mechanical integrated device and system with nano-characteristics in terms of system characteristic dimensions and effects following MEMS. Both MEMS and NEMS have the advantages of small size, light weight, low power consumption, high reliability, high sensitivity, and easy integration. These advantages enable MEMS and NEMS to cover almost all fields of natural and engineering sciences, such as chemistry, physics, biomedicine, materials science, energy science, electronic technology, and mechanical technology. Representative devices mainly include resonators, filters, accelerometers, microphones, gyroscopes, magnetic sensors, thermo-hygrometers, pressure gauges, and quantum state readout gauges in quantum computing systems. Compared with MEMS, NEMS has higher sensitivity, lower power consumption, higher integration, and smaller size, which can improve system performance and reduce costs. With the rapid advancement of recent research on advanced semiconductor materials and two-dimensional materials, MEMS and NEMS devices based on non-silicon or non-silicon-based materials have also been realized, such as gallium arsenide (GaAs) resonators, graphene thin film sensors, lithium niobate (LiNO3) on-chip optical resonators, etc.

[0003] The mechanical property tuning ability also has an important impact on the applications of MEMS and NEMS in different devices, such as the center frequency tuning of resonant filters, the dynamic feedback control of MEMS and NEMS, and the symmetry breaking control of non-linear resonators. Although MEMS and NEMS have many advantages, the mechanical property tuning ability of MEMS and NEMS also faces some challenges. For example, although silicon-based NEMS or MEMS devices have good compatibility and integration with modern microelectronic technologies, due to the high stiffness and / or stress of silicon-based NEMS or MEMS devices, it is very difficult to tune the mechanical properties of silicon-based NEMS or MEMS devices.

[0004] Currently, the solutions for tuning the mechanical properties of NEMS or MEMS devices are also limited to the following capabilities:

[0005] 1. Small-range tuning of the intrinsic frequency (by adjusting the stress) and symmetry breaking (by applying static deformation), about 1%-2% of the intrinsic frequency and static deformation of about a few nanometers;

[0006] 2. The design and manufacture of the tuning structure are relatively complex and space-consuming. The tuning structure mainly uses a large capacitive finger structure made of metal, which has a high area occupation ratio in NEMS or MEMS devices. An alternative can also be an on-chip heater, but their efficiency is limited. Especially in silicon-based devices, the frequency tuning efficiency is only 0.1%-1%.

[0007] Based on the above, it can be seen that the current methods for tuning the mechanical properties of NEMS or MEMS devices generally have problems such as complex tuning structures, small tuning ranges, and low efficiency. Therefore, there is an urgent need in the art to propose a new multi-layer structure for tuning and / or excitation to solve the defects existing in the prior art. Summary of the Utility Model

[0008] The purpose of the present utility model is to propose a multi-layer structure for tuning and / or excitation, which has a simple structure and is easy to implement. It can not only perform mechanical property tuning but also be used as an actuator for resonant applications. In addition, the structure of the present utility model is a planar thin two-dimensional structure. While being light in weight, it is directly integrated with the suspended non-metal layer in a micro-nano device on a plane, which can significantly reduce the size of NEMS or MEMS devices and the cost of NEMS or MEMS systems.

[0009] The technical solution adopted to achieve the purpose of the present utility model is:

[0010] A multi-layer structure for tuning and / or excitation, comprising: a substrate, a non-metal layer, a conductive two-dimensional material layer, and metal electrodes, wherein,

[0011] The non-metal layer is disposed on the upper surface of the substrate, and the non-metal layer can be bent or vibrated relative to the substrate;

[0012] The conductive two-dimensional material layer is disposed on the upper surface of the non-metal layer;

[0013] The metal electrodes are disposed above the conductive two-dimensional material layer, and the number of the metal electrodes is two or more. The metal electrodes can be bent or vibrated relative to the substrate; one end of each metal electrode is located on the surface of the overlapping part of the conductive two-dimensional material layer and the non-metal layer, and the other end extends to the upper surface of the non-metal layer and / or the substrate.

[0014] In the present utility model, the substrate, the non-metallic layer and the conductive two-dimensional material layer are electrically insulated from each other; the metal electrode is electrically insulated from the substrate and the non-metallic layer, is electrically connected to the conductive two-dimensional material layer, and forms a conductive path with the conductive two-dimensional material layer.

[0015] In the present utility model, the substrate, the non-metallic layer and the conductive two-dimensional material layer may have regular or irregular planar structures. When the above structure is an irregular planar structure, the other end of the metal electrode can extend to the upper surface of the non-metallic layer and / or the substrate.

[0016] Further, a groove or a through hole is formed on the substrate to form a suspended area, and the non-metallic layer and the conductive two-dimensional material layer are all or partially suspended above the suspended area; and one end of each metal electrode located at the overlapping part of the conductive two-dimensional material layer and the non-metallic layer is located above the suspended area.

[0017] In the present utility model, the resistance of the conductive two-dimensional material layer is less than the resistance of the metal electrode and / or the contact resistance between the metal electrode and the conductive two-dimensional material layer; and the thermal expansion coefficient of the metal electrode is greater than the thermal expansion coefficient of the non-metallic layer.

[0018] Further, the conductive two-dimensional material layer is a single-atom or multi-atom layer material.

[0019] Further, the conductive two-dimensional material layer is a single-atom layer, and its thickness is less than 2 nm.

[0020] Further, the conductive two-dimensional material layer is a multi-atom layer, and its thickness is less than 5 nm.

[0021] In the present utility model, the resistance of the metal electrode and / or the contact resistance between the metal electrode and the conductive two-dimensional material layer is twice or more or five times or more the resistance of the conductive two-dimensional material layer.

[0022] Further, an insulating and / or semiconductor material for increasing the contact resistance of the metal electrode is deposited at the interface between the conductive two-dimensional material layer and the metal electrode, and the thickness of the insulating and / or semiconductor material is less than 5 nm.

[0023] Further, the thermal expansion coefficient of the metal electrode is twice or more that of the non-metallic layer.

[0024] Further, the thermal expansion coefficient of the metal electrode is five times or more that of the non-metallic layer.

[0025] Further, two or more of the metal electrodes are arranged in an array as a whole.

[0026] In the present utility model, the non-metal layer has prestress.

[0027] The usage method of the above structure of the present utility model is as follows: An electrical signal is applied to two and / or more than two of the metal electrodes in a multi-layer structure for tuning and / or exciting, and the electrical signal causes a change in the temperature / temperature distribution of the multi-layer structure. The electrical signal includes a direct current signal or an alternating current signal.

[0028] When tuning the mechanical properties of the device (such as modulating the intrinsic frequency, non-linear coefficient, etc.), the power of the direct current and / or alternating current signal applied determines the degree to which the mechanical properties are tuned. When the power of the direct current and / or alternating current signal is greater than a threshold value, the multi-layer structure and / or its adjacent area undergoes deformation (spatial deflection or flexure), and the magnitude of the power of the direct current and / or alternating current signal determines the degree of deformation of the multi-layer structure and / or its adjacent area.

[0029] In actual use, the electrical signal includes components and / or mixtures of frequencies at the intrinsic frequency of the non-metal layer or sub-harmonic and / or super-harmonic frequencies of the intrinsic frequency.

[0030] The above-mentioned intrinsic frequency is the operating frequency of the device. When the electrical signal is used to excite the MEMS device, an alternating current signal is applied between any two of the metal electrodes in the multi-layer structure, and the excitation intensity is determined by the power of the alternating current signal. At the same time, due to the average thermal effect of the alternating current signal, the mechanical properties of the excited MEMS device will also be modulated accordingly.

[0031] In actual use, electrical signals with variable magnitudes and / or timings and / or signal patterns are applied to two or more of the metal electrodes. The electrical signals include sine waves, square waves, triangular waves, and arbitrary waves, and the changes in the electrical signals are controlled by programming to achieve programmable deformation, programmable parameter modulation, and / or programmable device excitation.

[0032] The multi-layer structure for tuning and / or exciting of the present utility model can be applied to a variety of devices, and has good applicability. For example, the multi-layer structure for tuning and / or exciting of the present utility model is applied to a micro-vibrating mirror; the application of the multi-layer structure for tuning and / or exciting in a fluid microcontroller; the application of the multi-layer structure for tuning and / or exciting in an atomic force microscope; the application of the multi-layer structure for tuning and / or exciting in a thin film bulk acoustic resonator. In the actual application process, it can also be applied to other suitable devices.

[0033] The technical principle of the present utility model lies in:

[0034] I. Tuning principle

[0035] The multi-layer structure for tuning and / or excitation of the present utility model (hereinafter referred to as "multi-layer structure") is a planar thin structure, belonging to the tuning structure on the two-dimensional surface of the chip, and is used to control various mechanical properties of the device. The multi-layer structure is based on a suspended non-metallic layer (the non-metallic layer includes but is not limited to silicon and / or silicon-based materials, semiconductor materials such as gallium arsenide, and lithium niobate, etc.). In this structure, there is a layer of conductive two-dimensional material (the conductive two-dimensional materials include but are not limited to graphene, black phosphorus, molybdenum disulfide, and chromium sulfur bromide, etc.) and metal electrodes.

[0036] When realizing the tuning function, an electrical signal is applied between two or more metal electrodes in the multi-layer structure to globally or locally change the temperature and / or temperature distribution of the multi-layer structure and / or its adjacent area. Due to the thermal expansion mismatch between the metal electrodes and the non-metallic layer, the change in the temperature and / or temperature distribution of the multi-layer structure and / or its adjacent area will cause a change in the stress distribution of the non-metallic layer and even static deflection (deformation), thereby realizing tuning and / or deformation control. Specifically: The thermal expansion itself is caused by Joule heating. Utilizing the high electrical conductivity of the two-dimensional material layer and the relatively high contact resistance at the interface between the metal electrode and the conductive two-dimensional material layer, the Joule heating is localized to a small overlapping area between the two-dimensional material layer and the metal electrode. The local voltage drop and related dissipation at the contact point cause the electrothermal mechanical effect, thereby realizing the tuning of the mechanical properties of the device.

[0037] II. Excitation principle

[0038] In addition to being used as a tuning structure, the multi-layer structure of the present utility model can also be used as an actuator for resonator applications to realize excitation. When realizing the excitation function, an alternating current signal or a direct current superimposed with an alternating current signal is applied between two metal electrodes to periodically drive and excite the vibration of the non-metallic layer.

[0039] The structural characteristics and scalability of the present utility model are introduced in detail below.

[0040] I. Brief introduction to the characteristics of the spatial arrangement of metal electrodes in the multi-layer structure

[0041] (1) Any pair or pairs of metal electrodes are not connected to each other, and are electrically connected through the two-dimensional material layer, that is, the two-dimensional material layer serves as the electrical connection path for the metal electrodes;

[0042] (2) The non-metallic layer and metal electrodes in a single and / or multiple multi-layer structures should meet the requirement that some or all of their structures have mechanical mobility, that is, they can form relative displacement or deformation with respect to the substrate or other fixed structures;

[0043] (3) The relative positions of a pair or pairs of metal electrodes can be in the same or different planes, but electrical connection needs to be realized in the two-dimensional material layer;

[0044] (4) By setting different positions of two or more metal electrodes, an array arrangement can be achieved.

[0045] II. An extended multi-layer structure can be achieved through the expansion of the interlayer material

[0046] A metal layer is further introduced between the conductive two-dimensional material layer and the non-metal layer to form a multi-layer structure from top to bottom: metal (such as gold) - conductive two-dimensional material (such as graphene) - metal (such as gold) - non-metal layer (such as silicon nitride). The two metal layers are respectively used as the top electrode and the bottom electrode to achieve the input of electrical signals, and the middle two-dimensional material layer is used as the heating and interface conductance material.

[0047] The beneficial effects of the present utility model are as follows: The structure of the present utility model is simple and easy to implement. It can not only perform mechanical property tuning but also be used as an actuator for resonance applications. In addition, the structure of the present utility model is a planar thin two-dimensional structure. While being lightweight, it can be directly integrated with the suspended non-metal layer in a silicon-based device on a plane, which can significantly reduce the size of silicon-based NEMS or MEMS devices and lower the cost of the NEMS or MEMS system. Furthermore, the structure of the present utility model can be applied to various devices and has strong applicability. Description of the Drawings

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will further describe the present utility model in conjunction with the drawings and embodiments. The drawings in the following description are only partial embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings:

[0049] Figure 1 It is an overall structural schematic diagram of the metal-graphene-silicon nitride thin film (MGS) tuning structure in Embodiment 1 of the present utility model.

[0050] Figure 2 is Figure 1 A structural schematic diagram of the cross-section along the A-A plane.

[0051] Figure 3 It is a partial enlarged schematic diagram of the flat structure of the silicon nitride thin film in Embodiment 1 of the present utility model.

[0052] Figure 4 It is a partial enlarged schematic diagram of the static deflection of the silicon nitride thin film in Embodiment 1 of the present utility model.

[0053] Figure 5 It is a model diagram and experimental result diagram of Experiment 1 in Embodiment 1 of the present utility model.

[0054] Figure 6 It is the experimental result diagram of Experiment 2 in Embodiment 1 of the present utility model.

[0055] Figure 7 It is the experimental result diagram of Experiment 3 in Embodiment 1 of the present utility model.

[0056] Figure 8 It is a schematic diagram of a demonstration structure of a scanning mirror or a gas measuring instrument in Embodiment 2 of the present utility model.

[0057] Figure 9 It is a schematic diagram of visualizing the scanning process by using an alternating current signal for the cross-section of the scanning mirror in Embodiment 2 of the present utility model.

[0058] Figure 10 It is a schematic diagram of a demonstration process of a microfluidic controller in Embodiment 3 of the present utility model.

[0059] Figure 11 It is a schematic diagram of a structure of a traditional AFM tip in Embodiment 4 of the present utility model.

[0060] Figure 12 It is a schematic diagram of applying the tuning structure in Embodiment 4 of the present utility model to the AFM tip.

[0061] Figure 13 It is a schematic diagram of using the tuning structure in a unit of an FBAR filter in Embodiment 5 of the present utility model.

[0062] In the figure: 1. Substrate; 2. Non-metallic layer; 3. Conductive two-dimensional material layer; 4. Metal electrode; 5. Suspended area; 401. Electrode I, 402. Electrode II, 403. Electrode III, 404. Electrode IV, 405. Electrode V. Detailed implementation manners

[0063] Next, the technical solutions in the embodiments of the present utility model will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0064] Embodiment 1

[0065] In the multi-layer structure of this embodiment, the material of the substrate 1 is silicon, the material of the non-metallic layer 2 is silicon nitride, and the material of the conductive two-dimensional material layer 3 is graphene. The overall structure of this embodiment is a "Metal-Graphene-SiN membrane tuning structure", abbreviated as "graphene multi-layer tuning structure".

[0066] Such as Figures 1 to 5As shown, the graphene multi-layer tuning structure of this embodiment sequentially includes a silicon substrate, a silicon nitride suspended film, and a graphene film from bottom to top, and further includes a metal electrode 4 connected to the edge of the upper surface of the graphene film. One end or multiple ends of the silicon nitride suspended film are anchored on the silicon substrate; one end of each of the metal electrodes 4 is located on the surface of the overlapping part of the silicon nitride suspended film and the graphene film, and the other end extends to the upper surface of the silicon substrate. The number of the metal electrodes 4 is two or more. Among the metal electrodes 4, at least two metal electrodes 4 are respectively arranged at the edges of any two opposite sides of the graphene film, and the other metal electrodes 4 are arranged at the right-angle edges or the edges of other sides of the graphene film. In this embodiment, a groove or a through hole is formed on the silicon substrate to form a suspended area 5. For the convenience of processing, the suspended area 5 in this embodiment is a through hole. The non-metal layer 2 and the conductive two-dimensional material layer 3 are all or partially suspended above the suspended area 5; and one end of each metal electrode 4 located at the overlapping part of the conductive two-dimensional material layer 3 and the non-metal layer 2 is located above the suspended area 5.

[0067] It should be noted that the "graphene multi-layer tuning structure" of the present utility model is a two-dimensional structure, Figure 2 the thickness does not represent the actual thickness, Figure 2 but only represents the connection relationship and the positional relationship of each part.

[0068] In this embodiment, silicon nitride is selected as the material of the non-metal layer 2, which has excellent mechanical properties, thermal stability, and chemical stability. The silicon nitride film in this embodiment is Si3N4 or SiN, preferably SiN. As the conductive channel, the graphene film is located on the upper surface of the silicon nitride film, and has the characteristics of high flexibility, small bending stiffness, and ultra-low mass, and the influence on the mechanical properties of the graphene multi-layer tuning structure of this embodiment can be ignored. In addition, the high optical transparency of the graphene film ensures that the optical characteristics of the silicon nitride film are minimally affected, which is also beneficial to the application of the graphene multi-layer tuning structure of this embodiment in the fields of micro-nano optical devices and the like.

[0069] In this embodiment, the graphene film and the silicon nitride film overlapping with the substrate are both anchored on the silicon substrate, and the part of the metal electrode 4 covering the graphene film is also anchored on the silicon substrate following the graphene film. The above method can ensure the stability of the structure, and the unanchored part is used as the free end to cooperate with the tuning and the bending vibration during excitation. The silicon substrate and the silicon nitride film referred to in the present utility model are common structures on current chips.

[0070] In this embodiment, the metal electrode 4 (such as an Au / Ti metal electrode) has high conductivity relative to the silicon nitride film, and the resistivity is less than 10 -1 Ωm (taking gold as an example, the typical value is 2.5×10 -8 Ωm), and a high coefficient of thermal expansion, and its coefficient of thermal expansion is greater than 4×10 -6 / K (taking gold as an example, 14.2×10 -6 / K) or the ratio of the coefficient of thermal expansion to that of the silicon nitride film is greater than 1:1. The graphene film has a low resistance value, and through certain manufacturing processes (such as surface oxidation, modification with specific organic molecules, etc.) or size design methods, it generates a high contact resistance with the metal electrode 4. The ratio of the resistance of the conductive channel of the graphene film to the contact resistance between it and the metal electrode 4 is less than 1:2, and the typical value is 1:10.

[0071] The metal selected for the metal electrode 4 in this embodiment is a metal commonly used as an electrode in existing micro-nano and semiconductor processing technologies, such as metals like titanium (Ti), gold (Au), aluminum (Al), platinum (Pt), and molybdenum (Mo), etc., or it can also be a composite metal electrode formed by a combination of different metals. The number of metal electrodes 4 can be selected according to actual needs, and the number is more than two. Among them, in the metal electrode 4, two electrodes are respectively arranged at the edges of any two opposite sides of the graphene film, and other electrodes are arranged at the right-angle edges or the edges of other sides of the graphene film to ensure that the current can pass through the graphene multi-layer tuning structure smoothly.

[0072] In this embodiment, the metal electrode 4 is a composite film of titanium (Ti) and gold (Au), and the total thickness is 50 nm. Since the principle of tuning by controlling the mechanical properties depends on the mechanical force caused by the thermal expansion mismatch between the metal electrode 4 and the silicon nitride film, therefore, this embodiment preferably selects a material combination with a large gradient of the coefficient of thermal expansion from the metal electrode 4 to the bottom silicon nitride film. The coefficients of thermal expansion of Ti and Au are α Au = 14.2×10 -6 / K, α Ti = 7.6×10 -6 / K; the coefficient of thermal expansion of the silicon nitride film is α SiN = 3.2×10 -6 / K. As a common adhesion promoter layer for Au electrodes in micro-nano processing and semiconductor technologies, the simultaneous use of Ti and Au can ensure that the coefficient of thermal expansion of the metal electrode 4 in this embodiment forms a large gradient with the silicon nitride film, thereby achieving good tuning and excitation performance.

[0073] In this embodiment, the parameters of the graphene multi-layer tuning structure are specifically as follows: the shape of the silicon nitride film is rectangular, with specific dimensions of 495×512 μm 2 , and the long side is defined as the direction of the x-axis, the short side is positioned as the direction of the y-axis, and the thickness of the silicon nitride film is not greater than 110 nm; the shape of the graphene film is square, with specific dimensions of 300×300 μm 2。 The number of metal electrodes 4 is five, and they are respectively named electrode I 401, electrode II 402, electrode III 403, electrode IV 404, and electrode V 405. Among them, electrode I 401 and electrode IV 404 are respectively arranged at the edges of the longer opposite sides of the graphene film; electrode III 403 and electrode V 405 are respectively arranged at the right-angle and left-angle positions on the right side of electrode IV 404; electrode II 402 is arranged on the side between electrode I 401 and electrode II 402. In the above structure, the resistance of the graphene film is about 1 kΩ, and the contact resistance R is about 10 - 20 times. The resistances between different metal leads are different. In the figure, electrode I 401, electrode II 402, electrode III 403, electrode IV 404, and electrode V 405 are respectively represented by the numbers 1, 2, 3, 4, and 5.

[0074] In this embodiment, part of the manufacturing method of the graphene multi-layer tuning structure is as follows: Deposit a silicon nitride film on a 0.5 mm thick commercial silicon wafer (i.e., silicon substrate), and the deposition method is low-pressure chemical vapor deposition (LPCVD). The single-layer graphene film is grown by chemical vapor deposition and transferred to the surface of the silicon nitride film by wet transfer, covering the entire silicon nitride film and part of the silicon substrate. Then, the graphene film is etched to be smaller than the size of the silicon nitride film by using etching technology. The graphene film is in contact with the metal electrode 4 prepared by electron beam evaporation, and the total thickness of the metal electrode 4 is about 50 nm.

[0075] When no voltage is applied to the structure of this embodiment, the silicon nitride film is a flat structure, and the partial enlarged view is as Figure 3 shown. By applying a DC signal between electrode I 401 and electrode IV 404, the stress of the silicon nitride film changes, and even static deflection occurs. The partial enlarged view of the static deflection of the silicon nitride film is as Figure 4 shown, thereby realizing tuning.

[0076] In this embodiment, the resistance of the conductive two-dimensional material layer is less than the resistance of the metal electrode and / or the contact resistance between the metal electrode and the conductive two-dimensional material layer; and the thermal expansion coefficient of the metal electrode is greater than that of the non-metal layer. Among them, the conductive two-dimensional material layer is a single-atom or multi-atom layer material. In this embodiment, the conductive two-dimensional material layer is preferably a single-atom layer, and the preferred thickness is 0.335 nm.

[0077] The resistance of the metal electrode and / or the contact resistance between the metal electrode and the conductive two-dimensional material layer is five times or more of the resistance of the conductive two-dimensional material layer. Theoretically, the greater the difference in thermal expansion coefficients between the metal electrode and the non-metal layer, the better, because the regulation, deformation, and excitation are all caused by the different degrees of expansion between the metal electrode and the non-metal layer due to the increase in temperature. That is, the more the metal electrode expands compared to the non-metal layer, the greater the force exerted on the non-metal layer. Based on the material selection principle of compatible semiconductor processes, five times is preferred in this embodiment.

[0078] Experimental System and Expectations

[0079] In this experiment, it is mainly expected that when different voltages are applied to the metal electrode 4, the morphological state of the silicon nitride thin film surface will change controllably.

[0080] This experiment is carried out based on applying a voltage between electrode I 401 and electrode IV 404 in the graphene multi-layer tuning structure. The voltage between electrode I 401 and electrode IV 404 is denoted as V. A white light interferometer is used to measure the three-dimensional morphology of the device surface. The three-dimensional model diagram of the experimental device is specifically as shown in Figure 5 (a) in the following.

[0081] During the expected measurement process, when there is no input voltage (V = 0), the surface of the silicon nitride thin film remains flat, specifically as shown in Figure 5 (b) in the following; when a DC voltage is input (V = V DC ), the static deformation of the silicon nitride thin film is specifically as shown in Figure 5 (c) in the following; when the input voltage is an AC voltage (V = V AC ), the periodic vibration of the silicon nitride thin film is specifically as shown in Figure 5 (d) in the following. By detecting these three expected phenomena, it can be proved that the graphene multi-layer tuning structure in Embodiment 1 of the present utility model can not only perform mechanical property tuning, but also be used as an actuator for resonance applications to achieve the excitation function.

[0082] Experiment 1

[0083] This experiment is mainly used to test the state of the silicon nitride thin film surface under DC conditions.

[0084] This experiment is carried out based on applying a voltage between electrode I 401 and electrode IV 404 in the graphene multi-layer tuning structure. A white light interferometer is used to measure the three-dimensional morphology of the sample in Embodiment 1. A DC signal is applied between electrode I 401 and electrode IV 404. Through the experiment, it is found that when the DC signal (V DC ) is less than 2.5 V, the graphene multi-layer tuning structure remains flat; when V DC exceeds approximately 2.5 V, the graphene multi-layer tuning device will undergo an out-of-plane static deflection.

[0085] Figure 6 (a) in the following shows a typical three-dimensional image of the static spatial deflection captured by measuring with an imaging white light interferometer when the voltage is further increased to V DC = 2.9 V. Figure 6 In (a) in the following, the number 1 represents the end where electrode I 401 is located, and the number 4 represents the end where electrode IV 404 is located.

[0086] Figure 6 (b) in the following representsFigure 6 In (a), the deflection profile of the film surface position represented by the black line, i.e., the out-of-plane deformation magnitude of the device position where the black line is located. The lowest points corresponding to the edges of electrode I 401 and electrode IV 404 are respectively marked as L1 and L4, indicating that the two maximum deformation values of the silicon nitride thin film correspond to the free end positions of electrode I 401 and electrode IV 404. Figure 6 In (b), the gray shaded area represents the radius of curvature r for extracting the out-of-plane static deflection (i.e., deformation). c The spatial range.

[0087] Figure 6 In (c), it is V DC During the process from 2.65 V to 2.9 V, the silicon nitride thin film has different r values extracted at different temperatures corresponding to different V DC The function obtained by plotting. The gray dots in the figure represent the r values at different temperatures. c The solid line is the theoretical curve plotted based on the model calculation, and the dashed line represents the buckling transition temperature T c . The inserted two-dimensional grayscale image in the figure is the curvature distribution image of the device obtained by testing at V t = 2.9 V. DC = 2.9 V.

[0088] Through Figure 6 It can be seen from (a) and (b) that the free ends of the graphene multi-layer tuning structure are bent. In this experiment, the strongest downward deflection is near the free ends of electrode I 401 and electrode IV 404. In Figure 6 In (a), the maximum deflection in the right region exceeds 1300 nm, which occurs near the edge of electrode I 401, that is, Figure 6 the lowest point L1 in (b). Figure 6 The lowest point of the edge of electrode IV 404 in (b) is L4. The images at different V DC show a similar bending pattern. When V DC is turned off, the silicon nitride thin film returns to its original flat state, proving that the deflection of the silicon nitride thin film within a certain DC current range is reversible.

[0089] Experiment 2

[0090] This experiment is mainly used to test the state of the silicon nitride thin film surface under the AC state. This experiment is carried out by applying an AC voltage between electrode I 401 and electrode IV 404 in the graphene multi-layer tuning structure, and a white light interferometer is used to measure the three-dimensional morphology and dynamic response of the device. Gradually apply an AC signal between electrode I 401 and electrode IV 404, V ACranges from 0.4V to 1.2V, with a step size of 0.2V. The driving frequency (i.e., the excitation frequency) and amplitude response of the silicon nitride thin film under the test AC signal are measured and plotted as corresponding function graphs, specifically as shown in Figure 7 As shown. It can be seen from the figure that as the value of V AC increases, the amplitude response of the silicon nitride thin film between electrode I 401 and electrode IV 404 increases with the increase of the value of V AC intensity, and it can make the device enter the nonlinear vibration state, proving that this structure can not only achieve the general excitation of the device, but also be used as the excitation structure of the nonlinear resonance device.

[0091] Example 2

[0092] In this example, the multi-layer structure of the present invention is applied to a micromirror. The micromirror can be a scanning mirror (i.e., a micro-vibrating mirror), a gas measuring instrument, or a MEMS mirror, etc., which are common in the prior art. Among them, the MEMS mirror is shown in "Low-Cost Electrothermal-Driven MEMS Mirror for High-Speed Linear Grating Scanning", Samanta et al., Optita9, 251 (2022). The MEMS mirror generally includes two parts: a suspended film with a metal layer and its MEMS actuator. The most important parameters of the MEMS mirror are the angular range, power consumption, and response time. A schematic diagram of a demonstration structure of a scanning mirror (micro-vibrating mirror) or a gas measuring instrument is shown in Figure 8 As shown. The cross-section of the scanning mirror visualizes the scanning process by using an AC signal as shown in Figure 9 As shown, and the scanning angle can be easily controlled by the intensity of the AC signal.

[0093] In this example, if the multi-layer structure of the present invention is used as the MEMS mirror surface, only two metal electrodes 4 are required. When current passes through the multi-layer structure of the present invention, the metal electrode 4 will deform, and the bent area in the figure is the mirror area for reflecting the laser beam. When a DC current is applied, the structure can statically change the reflection angle; when an AC signal is applied, the structure can be used as a scanning mirror (micro-vibrating mirror), for example, in the application of lidar. In this example, the non-metal layer 2 is, for example, a silicon nitride thin film; the two-dimensional material layer is, for example, a graphene thin film. The metal layer is, for example, a gold electrode 4. The high transparency of the graphene thin film ensures that their influence on the reflected laser beam can be ignored, and deformation can still occur even after heating. The multi-layer structure of the present invention has the following advantages in the application of the MEMS mirror: simpler structure, further miniaturization can be achieved; short response time, high working efficiency, and low power consumption.

[0094] Example 3

[0095] In this example, the multi-layer structure of the present invention is applied to a microfluidic controller, specifically as shown in Figure 10As shown in the figure, an insulator cover is placed on top of two metal electrodes 4 of the multi-layer structure of the present utility model. The insulator cover forms a closed fluid channel with the metal electrodes 4 and the two-dimensional material / non-metal layer 2 of the multi-layer structure of the present utility model. The cross-sectional area of the closed fluid channel can be controlled by the power of the electrical signal applied to the metal electrodes 4, thus forming a fluid flow microcontroller. Connect the fluid channel to the closed fluid channel and guide the fluid into the flow microcontroller. When no electrical signal is applied to the metal electrodes 4, the gap between the insulator cover and the non-metal layer 2 is very small, so the fluid flow rate is very low, which is the "closed state". When an electrical signal is applied to the metal electrodes 4 causing the non-metal layer 2 to deform, the fluid channel in the microcontroller becomes wider and the flow rate increases significantly, which is the "open state". Since the response time of the multi-layer structure of the present utility model in this embodiment is relatively short (up to the microsecond level), the formed flow microcontroller can also quickly switch states.

[0096] Embodiment 4

[0097] In this embodiment, the multi-layer structure of the present utility model is applied to an atomic force microscope (AFM). In a traditional AFM device, the AFM tip is deformed after being heated by the metal electrode 4 covering the top, and a traditional AFM tip is as Figure 11 shown. In order to introduce as much heat as possible, the metal electrode 4 must be connected for as long as possible and a high voltage must be applied, but this will be limited by the width of the metal electrode 4, that is, the breakdown voltage. After applying the multi-layer tuning structure integrating two-dimensional materials in the present utility model, the above limitations are solved. The multi-layer tuning structure of the present utility model will have a fast enough response, strong flexibility, can work normally at a higher voltage, and when an alternating current signal is applied, the AFM tip can execute a vibration mode.

[0098] Embodiment 5

[0099] In this embodiment, the multi-layer structure of the present utility model is applied to a thin film bulk acoustic resonator (FBAR). The intrinsic frequency of a traditional FBAR can be tuned by adding a direct current signal to the electrodes on the top and bottom. However, the effect produced by the traditional method is usually small, and a large direct current signal easily leads to the risk of breakdown and damage of the AlN piezoelectric layer. In this embodiment, by isolating some areas of the top electrode to integrate the multi-layer tuning structure in the present utility model, the FBAR incorporating the multi-layer tuning structure of the present utility model can significantly adjust its intrinsic frequency. Through appropriate circuit design, a large adjustment of the filter range can be achieved. A schematic diagram of using the multi-layer structure of the present utility model in a unit of an FBAR filter is as Figure 13 shown.

[0100] The specific embodiments described above further elaborate in detail on the purpose, technical solution, and beneficial effects of the present utility model. It should be understood that the above description is only the specific implementation method of the present utility model and is not used to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the gist of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A multi-layer structure for tuning and / or excitation, characterized in that, Including: A substrate (1), a non-metal layer (2), a conductive two-dimensional material layer (3), and metal electrodes (4), wherein The non-metal layer (2) is disposed on the upper surface of the substrate (1), and the non-metal layer (2) can be bent or vibrated relative to the substrate (1); The conductive two-dimensional material layer (3) is disposed on the upper surface of the non-metal layer (2); The metal electrodes (4) are disposed above the conductive two-dimensional material layer (3), and the number thereof is two or more, and the metal electrodes (4) can be bent or vibrated relative to the substrate (1); one end of each metal electrode (4) is located on the surface of the overlapping portion of the conductive two-dimensional material layer (3) and the non-metal layer (2), and the other end extends to the upper surface of the non-metal layer (2) and / or the substrate (1).

2. The multilayer structure for tuning and / or excitation according to claim 1, characterized in that, A groove or through hole is formed on the substrate (1) to form a suspended area (5), and the non-metal layer (2) and the conductive two-dimensional material layer (3) are all or partially suspended above the suspended area (5); and one end of each metal electrode (4) located at the overlapping portion of the conductive two-dimensional material layer (3) and the non-metal layer (2) is located above the suspended area (5).

3. The multilayer structure for tuning and / or excitation according to claim 1 or 2, characterized in that, The conductive two-dimensional material layer (3) is a single-atom or multi-atom layer material.

4. The multilayer structure for tuning and / or excitation according to claim 3, characterized in that, The conductive two-dimensional material layer (3) is a single-atom layer, and its thickness is less than 2 nm.

5. The multilayer structure for tuning and / or exciting according to claim 3, characterized in that, The conductive two-dimensional material layer (3) is a multi-atom layer, and its thickness is less than 5 nm.

6. The multilayer structure for tuning and / or excitation according to claim 1, 2, 4 or 5, characterized in that, An insulating and / or semiconductor material for increasing the contact resistance of the metal electrode (4) is deposited at the interface between the conductive two-dimensional material layer (3) and the metal electrode (4), and the thickness of the insulating and / or semiconductor material is less than 5 nm.

7. The multilayer structure for tuning and / or excitation according to claim 3, characterized in that, An insulating and / or semiconductor material for increasing the contact resistance of the metal electrode (4) is deposited at the interface between the conductive two-dimensional material layer (3) and the metal electrode (4), and the thickness of the insulating and / or semiconductor material is less than 5 nm.

8. The multilayer structure for tuning and / or excitation according to claim 1, 2, 4, 5 or 7, characterized in that, Two or more of the metal electrodes (4) are arranged in an array as a whole.

9. The multilayer structure for tuning and / or excitation according to claim 3, characterized in that, Two or more of the metal electrodes (4) are arranged in an array as a whole.

10. The multilayer structure for tuning and / or excitation according to claim 6, characterized in that, Two or more of the metal electrodes (4) are arranged in an array as a whole.

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