Mechanical oscillator quantum device based on semiconductor thin film material and preparation method thereof

Abstract

The present application proposes a mechanical oscillator quantum device based on semiconductor thin film materials and a preparation method thereof, wherein the mechanical oscillator quantum device comprises a square oscillator unit, comprising a square oscillator and an oscillator rectangular beam located at the four corners of the square oscillator; and a plurality of phonon crystal cells, wherein the plurality of phonon crystal cells are arranged periodically and symmetrically around the square oscillator unit with the square oscillator unit as the center, and the resonance frequency of the square oscillator unit is in the phonon band gap of the plurality of phonon crystal cells; wherein the square oscillator is connected to the adjacent plurality of phonon crystal cells through the oscillator rectangular beam, and the square oscillator unit and the plurality of phonon crystal cells belong to the same semiconductor thin film material. According to an embodiment of the present application, by setting the resonance frequency of the square oscillator Lame mode in the phonon band gap of the plurality of phonon crystal cells arranged periodically and symmetrically, the Lame mode has a lower mechanical energy dissipation.

Description

Technical Field

[0001] The present application relates to the technical field of quantum devices, and in particular to a mechanical oscillator quantum device based on semiconductor thin film materials and a preparation method thereof. Background Art

[0002] High-frequency f high-quality factor Q oscillator devices are important components of electronic devices, and have important applications in timing, frequency reference, signal processing, etc. On the other hand, high-frequency high-quality factor oscillators can be used to prepare macroscopic quantum states, and also have important application prospects in precision measurement, quantum entanglement characterization, and quantum decoherence mechanism research.

[0003] At present, the oscillator devices in most devices are made of quartz materials. Due to the incompatibility of quartz with modern semiconductor manufacturing processes, there are certain limitations on the reduction of the volume size of related devices. Thanks to the progress of modern semiconductor processes, the frequency and quality factor of micro-nano mechanical oscillators obtained through micro-nano processing technology are gradually improving. Compared with oscillators made of quartz materials, micro-nano mechanical oscillators have the advantages of small size, low power consumption, high quality factor, and compatibility with integrated circuits. High resonance frequency and high quality factor are necessary conditions for the application of micro-nano mechanical oscillators in high-precision sensing and detection.

[0004] For example, the minimum detectable force based on a micro-nanomechanical oscillator is proportional to ; Application in quantum field requires the condition fQ>k B T / ， where k B ,T, They are the Boltzmann constant, ambient temperature and reduced Planck constant. For example, at room temperature, the mechanical oscillator needs to satisfy fQ>3.9*10 14 Therefore, increasing the product of the frequency f and the quality factor Q of micro-nanomechanical oscillators is a necessary means to obtain advanced applications of micro-nanomechanical oscillators.

[0005] In order to improve the product value of the high frequency f and the high quality factor Q of the micro-nano mechanical oscillator, the applicant found that in the patent document with application number 202410621062.8, a single crystal diamond phononic crystal is proposed, which adopts a phononic crystal structure with a variable shape and an out-of-plane vibration mode based on a cantilever beam. Since the out-of-plane vibration mode has certain limitations in vibration frequency, high-precision sensing or quantum applications based on micro-nano mechanical oscillators need to further improve the mechanical vibration performance. Summary of the invention

[0006] The present application proposes a mechanical oscillator quantum device based on semiconductor thin film materials and a preparation method thereof, which are used to increase the product of the frequency f and the quality factor Q of the mechanical oscillator so that the obtained mechanical oscillator has higher frequency stability and longer phonon lifetime.

[0007] According to one aspect of the present application, a mechanical oscillator quantum device based on semiconductor thin film material is proposed, comprising: a square oscillator unit, comprising a square oscillator and an oscillator rectangular beam located at the four corners of the square oscillator; and a plurality of phonon crystal cells, wherein the plurality of phonon crystal cells are centered on the square oscillator unit and are periodically and symmetrically arranged around the square oscillator unit so that the resonance frequency of the Lame mode of the square oscillator unit is in the phonon band gap of the plurality of phonon crystal cells; wherein the square oscillator is connected to the adjacent plurality of phonon crystal cells through the oscillator rectangular beam, and the square oscillator unit and the plurality of phonon crystal cells are both made of semiconductor thin film material.

[0008] According to some embodiments, the plurality of phononic unit cells have the same symmetric structure.

[0009] According to some embodiments, the semiconductor thin film material includes single crystal diamond.

[0010] According to some embodiments, the side length of the square vibrator is determined according to the vibration frequency.

[0011] According to some embodiments, the phonon unit cell includes a unit cell subunit and a unit cell rectangular beam subunit, wherein the unit cell rectangular beam subunit is arranged in the middle position of the side length of the unit cell subunit, and adjacent unit cell subunits are connected by the unit cell rectangular beam subunit arranged on the unit cell subunit.

[0012] According to one aspect of the present application, a method for preparing a mechanical oscillator quantum device based on a semiconductor thin film material is proposed, comprising: injecting carbon particles into a preset diamond substrate to obtain a sacrificial layer; epitaxially growing a single crystal diamond layer on the preset diamond substrate including the sacrificial layer by chemical vapor deposition; performing spin coating, photolithography and development treatment on the single crystal diamond layer based on a preset structure to obtain a first preset pattern; depositing a metal layer in the first preset pattern to obtain a second preset pattern; etching an area in the second preset pattern where the metal layer is not deposited by a dry etching process to obtain a third preset pattern; releasing and cleaning the third preset pattern, To obtain a phononic crystal with the preset structure; wherein the preset structure includes: a square oscillator unit, including a square oscillator and oscillator rectangular beams located at the four corners of the square oscillator; and a plurality of phononic crystal cells, wherein the plurality of phononic crystal cells are centered on the square oscillator unit and are periodically and symmetrically arranged around the square oscillator unit, so that the resonance frequency of the Lame mode of the square oscillator unit is in the phonon band gap of the plurality of phononic crystal cells; wherein the square oscillator is connected to the adjacent plurality of phononic crystal cells through the oscillator rectangular beam, and the square oscillator unit and the plurality of phononic crystal cells are made of the same semiconductor thin film material.

[0013] According to some embodiments, the plurality of phononic unit cells are formed with the same symmetric structure.

[0014] According to some embodiments, the semiconductor thin film material includes single crystal diamond.

[0015] According to some embodiments, the side length of the square vibrator is determined according to a required vibration frequency.

[0016] According to some embodiments, the phonon unit cell includes a unit cell subunit and a unit cell rectangular beam subunit, wherein the unit cell rectangular beam subunit is arranged in the middle position of the side length of the unit cell subunit, and adjacent unit cell subunits are connected by the unit cell rectangular beam subunit arranged on the unit cell subunit.

[0017] According to the embodiment of the present application, by setting the Lame mode resonance frequency of the square oscillator in the phonon band gap of multiple phonon units arranged periodically and symmetrically, the Lame mode has lower thermoelastic dissipation. At the same time, by selecting single crystal diamond as the material for preparing the mechanical oscillator, the excellent mechanical properties of single crystal diamond are used to improve the Lame mode resonance frequency and quality factor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 A device block diagram of a mechanical oscillator quantum device based on semiconductor thin film materials according to an exemplary embodiment of the present application is shown. Figure 2a A schematic diagram of a square phononic unit cell structure with a side length of a according to an exemplary embodiment of the present application is shown.

[0020] Figure 2b A schematic diagram of a first Brillouin zone structure of a square unit cell structure according to an exemplary embodiment of the present application is shown.

[0021] Figure 2c A schematic diagram showing an energy band structure of a square unit cell structure according to an exemplary embodiment of the present application is shown.

[0022] Figure 3 A Lamé vibration mode shape according to an exemplary embodiment of the present application is shown.

[0023] Figure 4 A schematic structural diagram of a mechanical oscillator based on semiconductor thin film material according to an exemplary embodiment of the present application is shown.

[0024] Figure 5a A schematic diagram of a surface total displacement simulation of a Lame mode mechanical oscillator according to an exemplary embodiment of the present application is shown.

[0025] Figure 5b A schematic diagram of stress distribution simulation of a Lame mode mechanical oscillator according to an exemplary embodiment of the present application is shown.

[0026] Figure 6 A flow chart of a method for preparing a mechanical oscillator based on semiconductor thin film materials according to an exemplary embodiment of the present application is shown.

[0027] Figure 7 A schematic diagram of a preparation process of a mechanical oscillator based on semiconductor thin film materials according to an exemplary embodiment of the present application is shown. DETAILED DESCRIPTION

[0028] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this application will be comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted.

[0029] The described features, structures or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced without one or more of these specific details, or other modes, components, materials, devices, etc. may be adopted. In these cases, known structures, methods, devices, implementations, materials or operations will not be shown or described in detail.

[0030] In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices.

[0031] The terms "first", "second" and the like in the specification and claims of this application and the above drawings are used to distinguish different objects rather than to describe a specific order.

[0032] The following is a clear and complete description of the technical solution of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0033] Figure 1 A device block diagram of a mechanical oscillator quantum device based on semiconductor thin film materials according to an exemplary embodiment of the present application is shown, such as Figure 1 The mechanical oscillator quantum device shown includes a square oscillator unit 101 and a plurality of phonon unit cells 103 .

[0034] According to an embodiment of the present application, a mechanical oscillator quantum device includes a mechanical oscillator, and the mechanical oscillator further includes a square oscillator unit 101 and a plurality of phonon unit cells 103. The mechanical oscillator includes a micro-nano mechanical oscillator.

[0035] According to an embodiment of the present application, the square vibrator unit 101 includes a square vibrator and vibrator rectangular beams located at the four corners of the square vibrator; a plurality of phonon unit cells 103 are periodically and symmetrically arranged around the square vibrator unit 101 with the square vibrator unit 101 as the center, so that the Lamé mode resonance frequency of the square vibrator unit 101 is in the phonon band gap of the plurality of phonon unit cells 103. The square vibrator is connected to the adjacent plurality of phonon unit cells 103 through the vibrator rectangular beam, and the square vibrator unit 101 and the plurality of phonon unit cells 103 both include semiconductor thin film materials.

[0036] In some embodiments, the phonon unit cell includes a unit cell subunit and a unit cell rectangular beam subunit, wherein the unit cell rectangular beam subunit is arranged in the middle of the side length of the unit cell subunit, and adjacent unit cell subunits are connected by the unit cell rectangular beam subunit arranged on the unit cell subunit.

[0037] In a specific embodiment, the square oscillator is connected to multiple adjacent phonon unit cells 103 through an oscillator rectangular beam. It can be connected to the unit cell rectangular beam subunit of the phonon unit cell 103 or directly connected to the side length of the unit cell subunit, which is not limited here.

[0038] In a specific embodiment, a crystal refers to a material structure formed by atoms, ions or molecules arranged periodically according to certain rules, and has long-range order. Phononic crystals are a special type of crystal that consists of a periodic solid structure with macroscopic dimensions, in which the behavior of phonons (i.e., the quanta of lattice vibration) plays a key role in the crystal structure. Phononic crystals have periodically distributed elastic constants and densities. When phonons propagate, they are constrained by the periodic arrangement in the phononic crystal, forming an energy band structure and dispersion relation. The band gap that appears between energy bands is called a phonon band gap. The existence of a phonon band gap prevents waves in a specific frequency range from propagating in the phononic crystal, which can achieve the effect of vibration reduction and noise reduction.

[0039] The unit cell is the basic unit constituting the crystal. According to the embodiments of the present application, a plurality of phonon unit cells have the same symmetrical structure, wherein the structure of the phonon unit cell includes but is not limited to a square, a triangle, a hexagon, a circle, and the like.

[0040] In some embodiments, the unit cell rectangular beam subunit is arranged in the middle of the side length of the unit cell unit. For example, the unit cell rectangular beam subunit is arranged in the middle of each side length of the unit cell unit of the square, triangle or hexagonal structure. When the unit cell unit adopts a circular structure, the unit cell rectangular beam subunit is symmetrically arranged on the circular structure of the unit cell unit, and the number of unit cell rectangular beam subunits arranged on each unit cell rectangular beam subunit is the same.

[0041] like Figure 2a~2c As shown, among which, Figure 2aIt is a schematic diagram of a square phonon unit cell structure with a side length of a, wherein each phonon unit cell adopts a square structure, and a phonon unit cell rectangular beam is arranged in the middle position of each phonon unit cell side. Figure 2b Schematic diagram of the first Brillouin zone structure of a square unit cell structure. Figure 2c Schematic diagram of the energy band structure of the square unit cell structure. The gap region between the energy bands is the phonon band gap. In this embodiment, a plurality of phonon unit cells 103 are arranged periodically and symmetrically around the square oscillator unit 101 with the square oscillator unit 101 as the center, and the square oscillator is connected to the adjacent plurality of phonon unit cells through the oscillator rectangular beam, so that the Lame mode resonance frequency of the square oscillator unit 101 is in the phonon band gap of the plurality of phonon unit cells 103. By utilizing the phonon band gap, the wave of the resonance frequency of the Lame mode cannot propagate in the phonon crystal, so as to achieve the effect of vibration reduction and noise reduction.

[0042] When there are defects in the periodic structure of the phononic crystal, the elastic fluctuations within the frequency range of the phononic band gap will be confined to the defect. In the embodiment of the present application, by setting the resonance frequency of the Lame mode of the square oscillator unit 101 in the phononic band gap of multiple phononic unit cells 103, the Lame mode elastic wave is confined to the periodic structure of the phononic crystal to hinder the propagation of the elastic wave, thereby improving the quality factor of the mechanical oscillator, achieving the purpose of increasing the life of the oscillator, reducing vibration and noise, etc.

[0043] As mentioned above, the out-of-plane vibration mode used in the patent scheme with application number 202410621062.8 has certain limitations. For example, compared with the Lamé mode, the out-of-plane vibration mode usually has a lower resonance frequency and quality factor. According to an embodiment of the present application, the semiconductor thin film material includes a single crystal diamond material, and a high-performance micro-nano mechanical oscillator is prepared based on the Lamé mode (also known as the Lamé mode) of the diamond square oscillator. Among the vibration modes of the mechanical oscillator, the Lamé mode is a bulk acoustic wave mode. Compared with the out-of-plane vibration mode described in application number 202410621062.8, the Lamé mode has a higher vibration frequency. At the same time, since the Lamé mode is a bulk acoustic wave mode with equal volume changes, it has lower thermoelastic dissipation, so the Lamé mode also has a higher quality factor. In this embodiment, the Lamé mode of diamond is protected by the phonon band gap, thereby improving the quality factor of the mechanical oscillator, which can be applied to timing, precision sensing, frequency calibration, and quantum application development.

[0044] In a specific embodiment, the side length of the square vibrator is determined according to the vibration frequency, as shown in formula (1).

[0045] (1)

[0046] in,L The side length of the square oscillator, G is the shear modulus of the material, ρ According to the embodiment of the present application, in order to set the Lamé mode resonance frequency of the square oscillator within the phonon band gap, it is necessary to design according to the range of the phonon band gap, and the side length of the square oscillator and the length of the oscillator rectangular beam can be comprehensively considered, and no limitation is made here.

[0047] Compared with the Lame mode of silicon material, the resonant frequency of the Lame mode of the oscillator made of diamond material of the same size will be twice that of the one made of silicon material. The higher frequency will be beneficial to improve the signal transmission and data processing capabilities. Figure 3 The figure shows the shape of the Lame vibration mode. In this mode, the edges of the square plate of the oscillator are bent in opposite phases while keeping the volume of the plate unchanged, which makes the Lame mode have lower thermoelastic dissipation, so that the Lame mode has a high quality factor. On the other hand, compared with the out-of-plane vibration mode, the Lame mode has the ability to store more energy, making it less susceptible to nonlinear factors, which is beneficial to the improvement of the signal-to-noise ratio during signal transmission.

[0048] This application selects diamond as the material for preparing mechanical oscillators because diamond is a semiconductor material with good performance, its bandgap is 5.5 eV, and under normal conditions, most impurities in diamond are not easily thermally excited, and it itself has low intrinsic dissipation performance. Diamond is the hardest material in nature, with a Young's modulus of about 1100 GPa and a shear modulus of about 450 GPa at room temperature. Currently, silicon is the most commonly used material in the preparation of micro-nano mechanical devices, with a Young's modulus of about 180 GPa and a shear modulus of about 63 GPa. This makes it possible for mechanical oscillators prepared from diamond materials to have higher resonant frequencies than oscillators prepared from other materials at the same scale. In addition, diamond materials are highly stable and have stable performance under high temperature and high pressure. Therefore, devices based on diamond micro-nano mechanical oscillators are easier to use under extreme conditions.

[0049] Since the thickness of the surface is the same when the material is grown during the production process of the mechanical oscillator, the thickness of the obtained phonon unit cell and the square oscillator is the same. However, in practice, the thickness of the obtained phonon unit cell and the square oscillator may be uneven. However, the present application does not limit the thickness of the square oscillator and the plurality of phonon unit cells, that is, when the thickness of the square oscillator and the plurality of phonon unit cells is different, the embodiments of the present application are also applicable.

[0050] according to Figure 1In the embodiment shown, by arranging the square oscillator in the phonon band gap of a plurality of periodically symmetrically arranged phonon units, the Lamé mode has a lower thermoelastic dissipation. At the same time, by selecting diamond as the material for preparing the mechanical oscillator, the excellent mechanical properties and low intrinsic dissipation performance of single crystal diamond are utilized to improve the resonance frequency and quality factor obtained by the Lamé mode.

[0051] Figure 4 A schematic diagram of the structure of a mechanical oscillator based on a semiconductor thin film material according to an exemplary embodiment of the present application is shown. As mentioned above, when the periodic structure and the central defect of the phononic crystal are designed, the central defect is Figure 4 The example shown is a square oscillator, which can make the Lamé mode resonance frequency of the square oscillator in the band gap of the phononic crystal, so that the resonance mode of the square oscillator will be confined to the defect, thereby reducing the dissipation of the mechanical energy of the oscillator. Figure 4 As shown, the square oscillator unit is set in the central area of ​​the phononic crystal (compared to the periodic phononic unit cell, the central area is similar to a defect, so it is defined as a defect area in this application), so that the resonance frequency of the square oscillator unit Lamé mode is set in the phonon band gap of multiple phononic units, so that the elastic wave is confined to the defective part of the periodic structure of the phononic crystal to hinder the propagation of the elastic wave, thereby achieving the purpose of increasing the phonon life, reducing vibration and noise, etc. In this embodiment, the oscillator of the square structure is connected to the rectangular beam of the unit cell of the phononic unit cell through the oscillator rectangular beam, so that when the frequency of the Lamé vibration mode in the defective area falls in the phonon band gap, the quality factor of the mechanical oscillator is improved.

[0052] According to the embodiments of the present application, in order to place the square oscillator in the phonon band gap, it is necessary to comprehensively consider the side length of the square oscillator and the length of the rectangular beam of the oscillator according to the space of the phonon band gap, and no limitation is made here.

[0053] In practice, first of all, according to the properties of the material, for example, the single crystal diamond film cannot be too thick. Because the properties of a single crystal diamond film that is too thick cannot be guaranteed, and there is a problem of difficulty in etching. In addition, in order to prevent the final device size, to prevent the device from being too large and causing the processing process to break. Therefore, in a specific embodiment, first of all, the phononic unit cell structure is first determined, including the side length of the unit cell unit and the size of the rectangular beam in the middle of the side length, so that the band gap of the phononic crystal can be determined. Afterwards, the resonant frequency is selected, and according to the value of the frequency, as well as parameters such as the density of the material, the side length of the square oscillator and the size of the oscillator rectangular beam are finally determined so that the Lamé mode resonance frequency of the square oscillator is in the band gap of the phononic crystal.

[0054] In a vacuum environment, for a micro-nano mechanical oscillator, the most important factor affecting its energy dissipation is fixed dissipation, which comes from the strain at a fixed position that irreversibly dissipates mechanical energy into the environment through the base. Therefore, reducing the energy dissipation at a fixed position is the main way to improve the quality factor of the oscillator. According to an embodiment of the present application, a single crystal diamond micro-nano mechanical oscillator adopts a square structure and is arranged in the phonon band gap of a periodically arranged phonon unit cell, so that the resonance frequency of the Lame mode of the central defect vibration of the mechanical oscillator is located in the phonon band gap, thereby improving the quality factor of the Lame mode, so that the obtained mechanical oscillator has higher frequency stability and longer phonon lifetime.

[0055] Figure 5a and Figure 5b A simulation schematic diagram of a mechanical oscillator of a Lame mode according to an exemplary embodiment of the present application is shown, wherein: Figure 5a is the total displacement of the mechanical oscillator surface, Figure 5b is the stress distribution of the Lame mode of the mechanical oscillator. Among them, the Young's modulus of the single crystal diamond material is E 1100GPa, density 3500 kg / m 3 , Poisson's ratio is 0.2. The unit cell side length is 60 um, and the length of the rectangular beam connecting the unit cells is l b = 12 um, width w b = 2 um, the number of periodically arranged phonon units is 21*21, and 7*7 units are reduced in the middle, which is the defect area. The side length of the square oscillator in the defect area is l lame = 260 um, the width of the rectangular beams connecting the four corners is 10 um. The thickness of the entire quantum device is 3 um. The Lame mode under this condition is located within the band gap.

[0056] like Figure 5a As shown in , the Lame resonance mode is located in the central defect region. At the same time, under the protection of the surrounding phonon unit cells, the strain is concentrated in the defect region, while the edge displacement is almost zero. Figure 5b As shown, the stress of the Lame mode is concentrated at the center of the square defect, while the stress on the surrounding periodically arranged unit cell units and the oscillator rectangular beam connected to the phononic unit cell is very small, which fully demonstrates the reduction effect of the phononic crystal on fixed dissipation.

[0057] Figure 6 A flow chart of a method for preparing a mechanical oscillator based on semiconductor thin film materials according to an exemplary embodiment of the present application is shown. Accordingly, Figure 7 A schematic diagram of the preparation process of a mechanical oscillator based on semiconductor thin film material according to an exemplary embodiment of the present application is shown. Figure 6 or Figure 7The preparation method shown includes steps S601, S603, S605, S607, S609 and S611.

[0058] like Figure 6 or Figure 7 As shown, in step S601, carbon particles are implanted into a preset diamond substrate to obtain a sacrificial layer.

[0059] Due to the sp 3 The hybrid method has a stable structure and no friction interaction between grains in the single crystal property, which can bring lower intrinsic energy dissipation. Therefore, in this embodiment, in order to improve the quality factor of the diamond oscillator, single crystal diamond is selected as the device material. Figure 7 As shown, on a diamond substrate, carbon particles are injected into the diamond substrate by a carbon particle injection technique to obtain a sacrificial layer including a carbon particle damage layer. In practice, the depth of the carbon particle damage layer can be controlled by adjusting the energy and dosage of the injected carbon particles. The carbon particle damage layer will be converted into a graphite layer under the high temperature state of step S603, and the graphite layer will be etched away as a sacrificial layer in subsequent steps, thereby releasing and obtaining a mechanical oscillator.

[0060] In step S603, a single crystal diamond layer is epitaxially grown on a preset diamond substrate including a sacrificial layer by chemical vapor deposition.

[0061] like Figure 7 As shown, single crystal diamond is epitaxially grown on the surface of the sacrificial layer by microwave plasma vapor deposition using hydrogen and methane as growth gases. In practice, the speed and quality of diamond growth can be controlled by controlling the temperature and gas ratio during the growth process.

[0062] In step S605, the single crystal diamond layer is subjected to spin coating, photolithography and development processes based on the preset structure to obtain a first preset pattern.

[0063] like Figure 7 As shown, the single crystal diamond layer is subjected to a spinning treatment, and then subjected to a hot plate drying treatment. After being photolithographically processed according to a preset structure by an electron beam exposure machine, it is subjected to a developing treatment using a developer, so that a first preset pattern can be obtained on the single crystal diamond layer. The first preset pattern can be a pattern determined according to actual design requirements.

[0064] In the specific implementation, S1813 photoresist is used in the spinning process. The parameters of the electron beam exposure machine used in the photolithography process are Field: 500 μm; Current: 20 nA; Dose: 250 μC / cm 2Etc. During the development process, MF-319 developer can be used, and the surface is immersed in the developer. After removing impurities by shaking during the immersion process, it is cleaned with isopropyl alcohol and then blown dry with nitrogen.

[0065] In step S607 , a metal layer is deposited in the first preset pattern to obtain a second preset pattern.

[0066] In practice, the second preset pattern is a pattern determined according to actual design requirements.

[0067] like Figure 7 As shown, metal deposition is performed on the first preset pattern to protect the oscillator structure of the single crystal diamond in the subsequent etching process. The deposited metal includes but is not limited to one of aluminum, gold, titanium and chromium.

[0068] In step S609, the area where the metal layer is not deposited in the second preset pattern is etched by a dry etching process to obtain a third preset pattern.

[0069] like Figure 7 As shown, etching of the second preset pattern using inductively coupled plasma reactive ions in a pure oxygen environment can thin the unprotected area to a preset degree. In practice, the etching speed can be controlled by adjusting the power and oxygen flow rate during the reactive ion etching process.

[0070] In step S611, the third preset pattern is released and cleaned to obtain a phononic crystal having the preset structure.

[0071] like Figure 7 As shown, the metal layer and the graphite layer are etched away in a mixed solution of boiling sulfuric acid and nitric acid (for example, the mixing ratio of sulfuric acid and nitric acid is 2:1) to obtain a mechanical oscillator with a preset structure. In some embodiments, oxygen plasma is also used to clean impurities and damaged layers to reduce energy dissipation caused by impurities or damaged layers.

[0072] according to Figure 6 and Figure 7 In the embodiment of the present invention, the obtained mechanical vibrator has a preset structure. The preset structure includes: a square vibrator unit, including a square vibrator and vibrator rectangular beams located at the four corners of the square vibrator; and a plurality of phonon crystal cells, the plurality of phonon crystal cells are periodically and symmetrically arranged around the square vibrator unit with the square vibrator unit as the center, so that the square vibrator unit is in the phonon band gap of the plurality of phonon crystal cells; the square vibrator is connected to the plurality of phonon crystal cells through the vibrator rectangular beam, and the square vibrator unit and the plurality of phonon crystal cells both include semiconductor thin film materials.

[0073] According to an embodiment of the present application, the phonon unit cell includes a unit cell subunit and a unit cell rectangular beam subunit, wherein the unit cell rectangular beam subunit is arranged in the middle position of the side length of the unit cell subunit, and adjacent unit cell subunits are connected by the unit cell rectangular beam subunit arranged on the unit cell subunit.

[0074] In some embodiments, the plurality of phononic unit cells are formed with the same symmetric structure.

[0075] In other embodiments, the semiconductor thin film material includes single crystal diamond.

[0076] In practice, the side length of the square vibrator is determined according to the vibration frequency.

[0077] Optionally, the square oscillator and the plurality of phonon unit cells have the same thickness.

[0078] According to an embodiment of the present application, a quantum device is also proposed, which includes a mechanical oscillator as described above.

[0079] According to example embodiments, quantum devices include, but are not limited to, quantum memories and quantum interfaces.

[0080] Illustratively, the single crystal diamond phononic crystal provided in the present application has an ultra-long lifespan characteristic and can be prepared to a mechanical quantum state, and thus can be used to prepare a quantum memory for storing quantum information; and can also be used to prepare a quantum interface for the conversion of microwave quantum states and optical quantum states.

[0081] According to an embodiment of the present application, a phononic crystal type mechanical oscillator is prepared by utilizing a single crystal diamond material having a higher shear modulus, lower intrinsic dissipation, and resistance to extreme environments, and by setting the Lame mode resonance frequency of the square oscillator in the band gap formed by the phononic unit cell, a Lame vibration mode with a higher quality factor is obtained, thereby increasing the product value of the resonance frequency f of the mechanical oscillator and the quality factor Q, so that the quantum device obtained by using the mechanical oscillator can be applied to high-precision timing, high-efficiency isolators, high-precision sensing, and quantum technology, such as quantum storage, quantum synchronization, etc.

[0082] Finally, it should be noted that the above is only a preferred embodiment of the present application and is not intended to limit the present application. Although the present application is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions of the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A mechanical oscillator quantum device based on semiconductor thin film material, characterized in that: include: A square vibrator unit, comprising a square vibrator and vibrator rectangular beams located at four corners of the square vibrator; as well as A plurality of phonon unit cells, wherein the plurality of phonon unit cells are centered on the square oscillator unit and are periodically and symmetrically arranged around the square oscillator unit so that the Lamé mode resonance frequency of the square oscillator unit is in the phonon band gap of the plurality of phonon unit cells; Wherein, the square vibrator is connected to the adjacent plurality of phonon unit cells through the vibrator rectangular beam, and the square vibrator unit and the plurality of phonon unit cells are made of the same semiconductor thin film material; The semiconductor thin film material includes single crystal diamond.

2. The mechanical oscillator quantum device according to claim 1, characterized in that: The plurality of phonon unit cells have the same symmetrical structure.

3. The mechanical oscillator quantum device according to claim 2, characterized in that: The side length of the square vibrator is determined according to the vibration frequency.

4. The mechanical oscillator quantum device according to claim 3, characterized in that: The phonon unit cell comprises a unit cell subunit and a unit cell rectangular beam subunit, wherein the unit cell rectangular beam subunit is arranged in the middle of the side length of the unit cell subunit, and adjacent unit cell subunits are connected by the unit cell rectangular beam subunit arranged on the unit cell subunit.

5. A method for preparing a mechanical oscillator quantum device based on semiconductor thin film materials, characterized in that: include: Implanting carbon particles into a preset diamond substrate to obtain a sacrificial layer; epitaxially growing a single crystal diamond layer on the predetermined diamond substrate including the sacrificial layer by chemical vapor deposition; Performing spin coating, photolithography and development processing on the single crystal diamond layer based on a preset structure to obtain a first preset pattern; Depositing a metal layer in the first preset pattern to obtain a second preset pattern; Etching the area of ​​the second preset pattern where the metal layer is not deposited by a dry etching process to obtain a third preset pattern; releasing and cleaning the third preset pattern to obtain a phononic crystal having the preset structure; Wherein, the preset structure includes: A square vibrator unit, comprising a square vibrator and vibrator rectangular beams located at four corners of the square vibrator; and A plurality of phonon unit cells, wherein the plurality of phonon unit cells are centered on the square oscillator unit and are periodically and symmetrically arranged around the square oscillator unit, so that the resonance frequency of the Lamé mode of the square oscillator unit is in the phonon band gap of the plurality of phonon unit cells; wherein the square oscillator is connected to the plurality of adjacent phonon unit cells through the oscillator rectangular beam, and the square oscillator unit and the plurality of phonon unit cells are made of the same semiconductor thin film material; The semiconductor thin film material includes single crystal diamond.

6. The preparation method according to claim 5, characterized in that: The plurality of phonon unit cells are formed with the same symmetrical structure.

7. The preparation method according to claim 6, characterized in that: The semiconductor thin film material includes single crystal diamond.

8. The preparation method according to claim 7, characterized in that: The side length of the square vibrator is determined according to the vibration frequency.

9. The preparation method according to claim 8, characterized in that: The phonon unit cell comprises a unit cell subunit and a unit cell rectangular beam subunit, wherein the unit cell rectangular beam subunit is arranged in the middle of the side length of the unit cell subunit, and adjacent unit cell subunits are connected by the unit cell rectangular beam subunit arranged on the unit cell subunit.

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