A method and device for atomically fabricating two-dimensional transition metal chalcogenide based on controllable micro-explosion

Abstract

This invention relates to an atomic-level manufacturing method and apparatus for two-dimensional transition metal chalcogenides based on controllable micro-explosions, belonging to the field of two-dimensional semiconductor materials and atomic-level precision manufacturing technology. This invention uses energetic transition metal complexes and energetic chalcogenides as integrated metal-energy precursors. Under the constraint of an array-type nano-confined microcavity, controllable micro-explosions are synchronously triggered by nanosecond lasers. Combined with directional templates and a uniform electric field, nanosecond-level stoichiometric precision is achieved in the directional self-assembly of two-dimensional transition metal chalcogenides. This invention compresses the fabrication cycle of a single 8-inch wafer to less than 10 minutes, with overall energy consumption less than 1% of traditional CVD processes. It allows for precise control of the number of layers and crystal orientation, and the carrier mobility of the prepared material is 100% compatible with existing semiconductor production lines, making it suitable for large-scale manufacturing in fields such as advanced logic chips, photodetectors, and energy storage devices.

Description

[0001] This invention belongs to the fields of two-dimensional semiconductor material manufacturing, atomic-level precision manufacturing, and advanced electronic device material manufacturing technology. Specifically, it relates to an atomic-level directional preparation method of two-dimensional transition metal chalcogenides based on controllable micro-explosion of energetic precursors, as well as a supporting manufacturing device for realizing this method. It can be directly applied to the large-scale manufacturing of two-dimensional semiconductor materials in fields such as advanced logic chips, photodetectors, energy storage devices, and flexible electronics.

[0002] Two-dimensional transition metal chalcogenides (TMDs, typically such as...) ) is a two-dimensional semiconductor material with a graphene-like layered structure. It has a moderate band gap of 1-2eV, ultra-high carrier mobility, excellent photoelectric conversion characteristics and mechanical flexibility. It is a core candidate material for breaking through the size limit of silicon-based chips and continuing Moore's Law. It has irreplaceable application value in advanced process chips below 2nm, 6G optoelectronic communication, new energy storage and other fields.

[0003] Currently, the mainstream manufacturing technologies for two-dimensional transition metal chalcogenides worldwide face insurmountable industry challenges, specifically as follows:

[0004] Chemical vapor deposition (CVD): The mainstream fabrication process for wafer-level TMDs worldwide. It requires a high temperature environment of 800-1000℃, using metal oxides as the metal source and sulfur / selenium powder as the chalcogenide source, and growth is carried out through gas phase transport. The growth cycle of a single 8-inch TMD film is as long as 4-8 hours, with extremely high energy consumption. Moreover, it has core problems such as difficulty in accurately controlling the ratio of metal source to chalcogenide source, many grain boundary defects, poor layer uniformity, and extreme difficulty in wafer-level single crystal growth. The carrier mobility of the prepared material is far below the theoretical limit, which cannot meet the application requirements of advanced process chips.

[0005] Mechanical exfoliation: the only method capable of preparing high-quality monolayer TMDs single crystals, but it can only achieve laboratory-level manual serial preparation, and the production capacity is far from meeting the needs of industrial mass production. More than twice as many times, making it completely impossible to scale up for application.

[0006] Liquid phase exfoliation: The mainstream preparation process for industrial-grade TMDs powders. It involves ultrasonically exfoliating bulk materials with strong acid. The resulting nanosheets have high defect density, uneven size, and uncontrollable number of layers. They can only be used for low-end energy storage fillers and cannot meet the high-end application requirements of semiconductor devices. In addition, the production process generates a large amount of acid and alkali waste liquid, causing serious environmental pollution.

[0007] Existing electric field-assisted directional growth technology can only help optimize the crystal orientation of CVD growth, and still requires long-term high-temperature growth for several hours. It cannot solve the core problems of long preparation cycle and many grain boundaries, and cannot achieve uniform growth of the whole wafer at the wafer level.

[0008] In summary, existing technologies have consistently failed to simultaneously achieve the five core objectives of low temperature and low energy consumption, wafer-level mass production efficiency, precise control of atomic-level layer number and stoichiometry, high quality and low defects, and green safety. These shortcomings have become the core bottlenecks hindering the large-scale development and high-end application of the global two-dimensional transition metal chalcogenide industry. Currently, there are no publicly available technological solutions worldwide that can address all of these pain points.

[0009] The purpose of this invention is to overcome the aforementioned defects of the prior art and provide a method and apparatus for atomic-level manufacturing of two-dimensional transition metal chalcogenides based on controllable micro-explosion. This invention breaks through the traditional technical logic of "separation of metal source and chalcogenide source, and high-temperature long-term growth" in the preparation of TMDs. It uses transition metal energetic complexes + chalcogenide energetic compounds as an integrated carrier of "metal source + chalcogenide source + energy source". Through the synergistic effect of nanoscale confinement, directional template anchoring, and synchronous field-controlled orientation technology, it achieves the directional preparation of nanosecond-level high-quality TMDs. At the same time, it is 100% compatible with existing 8 / 12-inch semiconductor wafer production lines, and completely solves the industry pain points of high energy consumption, low efficiency, high cost, many grain boundary defects, and uncontrollable stoichiometry in the prior art.

[0010] The core inventive concept of this invention is as follows: using a metal chalcogenide-energy integrated energetic precursor system, a controllable micro-explosion is synchronously triggered by a nanosecond laser within a wafer-level array-type nano-confined microcavity, simultaneously releasing the high-temperature and high-pressure thermodynamic environment and highly active transition metal, sulfur / selenium atomic raw materials required for TMDs growth; combined with a pre-positioned chalcogenide growth template and a directional uniform electric field, the directional self-assembly of atoms, TMDs sheet growth and structural formation are completed within the nanosecond time window of the explosion, realizing the one-step completion of "ignition-nucleation-film formation", completely subverting the traditional long-term high-temperature heating logic of TMDs manufacturing.

[0011] Compared with the prior art, the present invention has the following disruptive and beneficial technical effects: 1. Achieving a breakthrough in production efficiency and completely overturning the industry's production cycle: Compared with the 4-8 hour wafer-level TMDs growth cycle of traditional CVD processes, the production efficiency of this invention is increased by more than 200 times, compressing the TMDs preparation cycle of a single 8-inch wafer to less than 10 minutes, perfectly matching the mass production rhythm of semiconductor wafer production lines, and completely solving the core pain point of extremely low production efficiency in existing technologies.

[0012] 2. Energy consumption and manufacturing costs drop dramatically: This invention does not require long-term heating at ultra-high temperatures of 800℃+, and the overall energy consumption is less than 1% of that of traditional CVD processes; the atomic utilization rate of energetic precursors is close to 100%, there is no waste of raw materials, and the overall manufacturing cost can be reduced by more than 90%, completely breaking the cost barrier of the TMDs industry.

[0013] 3. Atomic-level precise control, with fully controllable stoichiometry and crystal orientation: This invention achieves precise control of the molar ratio of metal to chalcogens in TMDs at 1:2 with an error ≤0.1% through precursor stoichiometry pre-matching, nano-confinement, and electric field orientation modulation. It can precisely prepare 1-3 layer few-layer structures or monolayer structures with consistent crystal orientation and no grain boundaries. The prepared TMDs exhibit high room-temperature carrier mobility. Defect density It fully meets the high-end application requirements of advanced semiconductor devices.

[0014] 4. Green and safe, with no environmental or safety risks: The decomposition products of the energetic precursor of this invention are only the constituent atoms of the target material and harmless nitrogen gas, with no toxic waste gas, waste liquid, or solid waste emissions. There is no need to use flammable, explosive, or toxic sulfur / selenium powder or metal organic sources, which meets the green manufacturing standards. At the same time, the nano-confined micro-explosion is completely confined within the microcavity, with no risk of energy diffusion or runaway, and the production process is safe and controllable.

[0015] 5. 100% compatible with existing semiconductor production lines, enabling rapid mass production: All core process modules of this invention adopt mature mass production technologies from the existing semiconductor and panel industries. There is no need to build a new entire industrial chain. It can be directly upgraded on existing silicon-based and silicon carbide production lines in a modular fashion, and industrialization can be achieved within 3-5 years without any technological gaps. At the same time, it can share a set of equipment with silicon carbide, graphene, and hexagonal boron nitride preparation processes, achieving "one machine for multiple production" and greatly improving equipment utilization.

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with preferred embodiments. All other embodiments obtained by those skilled in the art based on the core concept of this invention without creative effort are within the scope of protection of this invention.

[0017] Unless otherwise specified, the raw materials and equipment used in the specific embodiments of this invention are all commercially available conventional products; the process methods used are all conventional technical methods in the field unless otherwise specified.

[0018] The core equipment used in this embodiment of the invention includes: a 248nm / 193nm nanosecond pulsed excimer laser and a high-vacuum reaction chamber (ultimate vacuum). It is equipped with a turbomolecular pump group, an inductively coupled plasma (ICP) etching machine, a PECVD thin film deposition system, a high-precision micro-liquid injection system, and a 308nm excimer laser annealing module; the core detection methods include: Raman spectroscopy to test the number of TMDs layers / defects, atomic force microscopy (AFM) to test surface roughness, transmission electron microscopy (TEM) to observe the layer structure and crystal orientation, Hall effect testing system to test carrier mobility, and X-ray photoelectron spectroscopy (XPS) to test elemental stoichiometry.

[0019] Example 1: Wafer-level preparation of monolayer molybdenum disulfide (MoS2) thin films (for advanced chips)

[0020] This embodiment is used to prepare an 8-inch monolayer molybdenum disulfide thin film for advanced process chips below 2nm and photodetectors. The specific steps are as follows: 1. Substrate pretreatment and growth template preparation: An 8-inch sapphire substrate was selected. After polishing and cleaning, an array of nano-confined microcavities was prepared on the substrate surface using photolithography and ICP dry etching. The planar size of a single microcavity was 2μm×2μm and the depth was 500nm. The fill factor of the microcavity array was 95%. The inner wall of the microcavity was modified by plasma chalcogenization and used as a directional template for the growth of molybdenum disulfide. 2. Preparation and Filling of Integrated Chalcogenide-Energy Precursor: Using molybdenum dicarbonyl dicmolybdenum as the transition metal energetic complex (molybdenum source) and azidothiobenzene as the chalcogenide energetic compound (sulfur source and detonation source), the precursors were precisely mixed at a molar ratio of 1:2, with anhydrous toluene as the solvent, and stirred for 30 min in an anhydrous and oxygen-free glove box to prepare a homogeneous energetic precursor solution with a total solute mass concentration of 6%. The solution was then subjected to a vacuum of [insert vacuum level here]. Under high vacuum conditions, a micro-volume injection system was used to precisely fill all microcavities with the precursor solution, achieving a filling error of ≤0.1%. A 100nm thick layer was deposited using PECVD technology. A thin film is used to seal the opening of the microcavity; 3. Pre-field control and pre-temperature control: Place the filled substrate on the high-precision heating stage of the vacuum reaction chamber, and evacuate the vacuum reaction chamber to... The substrate was heated to 600°C and held at that temperature under extreme vacuum, while parallel plate electrodes were applied to the upper and lower sides of the substrate. A uniform electric field perpendicular to the substrate surface; 4. Controllable micro-explosion and directional growth of molybdenum disulfide: A 248nm nanosecond pulsed excimer laser was used for full-area exposure of the substrate, with a laser energy density of [missing information]. The pulse width is 20ns, and the energy uniformity of the entire wafer is ≤0.3%. The laser synchronously triggers nanosecond-level controllable micro-explosions in all precursors within the microcavities. The precursors decompose to generate highly active molybdenum atoms, sulfur atoms, and nitrogen protective gas, while simultaneously releasing instantaneous high temperature of 1500K and instantaneous high pressure of 10GPa. Under the synergistic constraints of the chalcogenide template, uniform electric field, and laser polarization, molybdenum atoms and sulfur atoms complete stoichiometric self-assembly in situ within the microcavities with a stoichiometric ratio of 1:2, generating a monolayer of molybdenum disulfide that matches the template. 5. In-situ post-processing: After the micro-explosion reaction is completed, the substrate is annealed in milliseconds using a 308nm excimer laser with a peak annealing temperature of 1000℃ and an annealing time of 5ms to repair the lattice defects of molybdenum disulfide. At the same time, high-purity argon gas with a purity of 99.9999% is introduced to passivate the molybdenum disulfide at a low temperature of 180℃ for 30s. The nitrogen gas generated by the reaction is extracted by a molecular pump system, and after cooling to room temperature, the substrate is removed to obtain the target 8-inch monolayer molybdenum disulfide film.

[0021] Performance test results: The molybdenum disulfide thin film prepared in this embodiment has a pure monolayer structure, and the full width at half maximum (FWHM) of the characteristic peak in the Raman spectrum is [data missing]. No defective peaks; XPS testing showed a Mo:S molar ratio of 1:2.002, with precise stoichiometry; room temperature carrier mobility reached [value missing]. Defect density With a surface roughness Ra<0.3nm and a thickness uniformity of ±0.5%, it can be directly used for the manufacture of advanced logic chips and photodetectors; the total time for single-wafer preparation is <8 minutes, and the comprehensive energy consumption is only 0.6% of that of traditional CVD processes.

[0022] Example 2: Few-layer tungsten disulfide ( Nanosheet preparation (for energy storage / catalysis)

[0023] This embodiment is used to prepare few-layer tungsten disulfide nanosheets for lithium-ion battery anodes and hydrogen evolution catalysis. The specific steps are as follows: 1. Substrate pretreatment and growth template preparation: A titanium foil substrate was selected, and a three-dimensional mesh-like nano-confined microcavity was prepared on the substrate surface using MEMS technology. The microcavity pore size was 5 μm and the depth was 10 μm. The inner wall of the microcavity was modified with chalcogenide. 2. Precursor Preparation and Filling: Using tungsten hexacarbonyl as the transition metal energetic complex (tungsten source) and azidothiobenzene as the chalcogenide energetic compound (sulfur source and initiation source), a homogeneous precursor solution with a total solute mass concentration of 10% was prepared by precise mixing at a molar ratio of 1:2 and using anhydrous tetrahydrofuran as the solvent. Microcavity filling and... Membrane sealing; 3. Pretreatment: Heat the substrate to 700℃ and apply... A vertical uniform electric field, with the vacuum level maintained at ; 4. Synchronous Micro-Explosion and Nanosheet Forming: A 193nm nanosecond pulsed excimer laser was used to expose the entire substrate surface, with a laser energy density of [missing information]. With a pulse width of 15ns, it synchronously triggers controllable micro-explosions in all precursors within the microcavities, completing the in-situ formation of few-layer tungsten disulfide nanosheets in one step. 5. In-situ post-processing: The lattice defects were repaired by 1100℃ millisecond-level laser annealing, and the substrate was passivated by argon gas at 200℃ for 30s. After the reaction gas was removed, the substrate was taken out and the titanium foil substrate was removed by acid washing to obtain pure few-layer tungsten disulfide nanosheets.

[0024] Performance test results: The tungsten disulfide nanosheets prepared in this embodiment have a few-layer structure of 2-3 layers, with a specific surface area of ​​up to It exhibits a cycle charge-discharge stability of >8000 cycles and a hydrogen evolution reaction overpotential of only 120mV, making it suitable for direct use as a negative electrode in lithium-ion batteries and a catalyst for hydrogen evolution in water electrolysis.

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly described below. These drawings constitute a part of this specification and are used to further understand the present invention. They are used together with the specific embodiments of the present invention to explain the present invention and do not constitute a limitation thereof.

[0026] Figure 1 This is a schematic diagram of the overall structure of the two-dimensional transition metal chalcogenide atomic-level manufacturing apparatus described in this invention;

[0027] Figure 2 This is a process flow diagram of the atomic-level manufacturing method of two-dimensional transition metal chalcogenides according to the present invention;

[0028] Figure 3 This is a schematic diagram of the cross-sectional structure of the array-type nano-confined microcavity described in this invention;

[0029] Figure 4 This is a schematic diagram illustrating the principle of the controllable micro-explosion directional growth of two-dimensional transition metal chalcogenides as described in this invention.

[0030] The component names marked in the attached diagram are as follows: 1-Vacuum reaction chamber system; 2-Upper electrode; 3-Lower electrode; 4-Substrate heating stage; 5-Conductive growth substrate; 6-Laser incident window; 7-Vacuum evacuation port; 8-Protective gas (argon) inlet; 9-Electrode terminals; 10-Array-type nano-confined microcavity; 11-Nanosecond-level controllable micro-explosion region; 12-Highly active transition metal atoms and sulfur / selenium atoms; 13-Chalcogenide growth template; 14-Precursor filling and sealing system; 15-Wafer-level laser synchronous triggering system.

Claims

1. A method for two-dimensional transition metal chalcogenide atomic-scale fabrication based on controllable micro-explosion, characterized in that, The method comprises the following steps: S1 substrate pretreatment and growth template preparation: select a conductive substrate as a growth base, prepare an array type nano-limited microcavity on the surface of the substrate, the inner wall of the nano-limited microcavity is modified by a chalcogen group, and the nano-limited microcavity is used as a directional template for growth of a two-dimensional transition metal chalcogen compound; S2 Metal chalcogenide - energy integrated precursor preparation and filling: using transition metal energy-containing complex as metal source, using chalcogen energy-containing compound as sulfur / selenium source and detonation source, adding doped element precursor as needed, obtaining homogeneous energy-containing precursor with precise stoichiometric ratio; under the vacuum degree of high vacuum environment, the energy-containing precursor is precisely filled into the nano-limited microcavity, and the microcavity opening is sealed. S3 pre-control temperature: place the filled substrate in a vacuum reaction chamber, heat the substrate to a pre-control temperature interval of 400-800 DEG C, and apply a directional uniform electric field perpendicular to the surface of the substrate on the upper and lower sides of the substrate; S4 controllable micro-explosion and directional growth of two-dimensional transition metal chalcogen compound: expose the substrate to nanosecond pulse excimer laser for whole wafer surface exposure, and synchronously trigger nanosecond controllable micro-explosion of the energy-containing precursor in all nano-limited microcavities; the energy-containing precursor decomposes to generate high-activity transition metal atoms, sulfur / selenium atoms, and nitrogen protective gas, and releases 1000-2000K instantaneous high temperature and 5-18GPa instantaneous high pressure; under the synergistic constraint of the chalcogen template, the uniform electric field and the laser polarization, the transition metal atoms and the sulfur / selenium atoms complete in-situ directional self-assembly with accurate stoichiometric ratio in the microcavity, and generate a single layer / few layer two-dimensional transition metal chalcogen compound matched with the template; S5 in-situ post-treatment: after the micro-explosion reaction is completed, millisecond laser annealing is performed on the substrate to repair lattice defects, high-purity inert gas is introduced for low-temperature passivation treatment of the material surface, and the protective gas generated in the reaction is removed through a vacuum system, and finally the target two-dimensional transition metal chalcogen compound structure is obtained.

2. The production method according to claim 1, characterized by The transition metal energetic complex is one or more of azido complexes, carbonyl complexes of molybdenum, tungsten, niobium, tantalum; the chalcogen energetic compound is one or more of azidosulfurbenzene, azidoselenophene; the two-dimensional transition metal chalcogen compound is one of MoS2, WS2, MoSe2, WSe2, NbSe2, TaSe2.

3. The production method according to claim 2, characterized by, The homogeneous energy-containing precursor is anhydrous and oxygen-free solution, the solvent is anhydrous toluene or anhydrous tetrahydrofuran, the molar ratio of transition metal to sulfur / selenium element is 1:2, and the total solute mass concentration is 2%-15%.

4. The production method according to claim 1, characterized by The conductive substrate is one of sapphire, silicon wafer, copper foil and nickel foil, the depth of the nano-limited microcavity is 2nm-30μm, and the plane size of a single microcavity is 10nm-50μm, which is prepared by MEMS lithography and dry etching process.

5. The production method according to claim 4, characterized by In step S2, a 50-150nm thick SiO2 film is deposited by PECVD process to seal the microcavity opening, and the filling amount error of the precursor in a single microcavity is ≤0.1%.

6. The production method according to claim 1, characterized by The field strength of the directional uniform electric field in the step S3 is , and the vacuum degree of the vacuum reaction cavity is .

7. The production method according to claim 1, characterized by The wavelength of the nanosecond pulsed excimer laser in the step S4 is 193nm or 248nm, the laser energy density is , the pulse width is 10-100ns, and the energy uniformity of the whole wafer in surface exposure is ≤0.5%.

8. The production method according to claim 1, characterized by In the step S4, the instantaneous high temperature of the controllable micro-explosion is maintained for 10-80ns, and the generated two-dimensional transition metal chalcogen compound is a 1-3 layer few-layer structure or a single layer structure, and the sheet size is 0.5-10μm.

9. The production method according to claim 1, characterized by In the step S5, the peak temperature of laser annealing is 800-1200 DEG C, the passivation temperature of inert gas is 120-220 DEG C, the passivation time is 10-60s, the inert gas is argon or nitrogen, and the purity is ≥99.9999%.

10. The manufacturing method according to any one of claims 1 to 9, characterized in that, Prepared two-dimensional transition metal chalcogenide room temperature carrier mobility , defect density , surface roughness .

11. An apparatus for atomic-scale manufacturing of two-dimensional transition metal chalcogenide compounds implementing the manufacturing method of any one of claims 1-10, characterized in that, It comprises: High vacuum reaction cavity system, equipped with high precision substrate heating table, molecular pump pumping unit and multi-channel gas passage, limit vacuum degree ; a precursor filling and sealing system, comprising a high-vacuum micro-liquid injection unit and a nanoscale film sealing unit, which is used for precise filling and microcavity sealing of the energy-containing precursor in a high-vacuum environment; Electric field regulation system, including parallel flat electrodes and high-precision high-voltage power supply, can output field intensity Adjustable vertical uniform electric field The wafer-level laser synchronous triggering system includes a nanosecond pulsed excimer laser with wavelengths of 193nm / 248nm and pulse widths of 10-100ns, as well as a surface exposure homogenizing optical path, which can achieve uniform exposure of the entire 8 / 12-inch wafer with energy uniformity ≤0.5%. The in-situ post-processing system, including a millisecond-level laser annealing module and an inert gas atmosphere control unit, is used for lattice repair and surface passivation of materials, and can achieve millisecond-level laser annealing at 800-1200℃ and inert gas passivation treatment at 120-220℃. The closed-loop measurement and control system is electrically connected to the above systems and is used for real-time monitoring and closed-loop control of vacuum degree, temperature, electric field intensity, laser parameters and reaction process.

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