In-situ stabilizing two-dimensional black phosphorus atomic-level manufacturing method and device based on controllable micro-explosion

Abstract

This invention relates to an in-situ stabilization method and apparatus for atomic-level manufacturing of two-dimensional black phosphorus based on controllable micro-explosion, belonging to the field of two-dimensional semiconductor materials and atomic-level precision manufacturing technology. This invention uses a phosphorus-based energetic compound as a phosphorus source-energy integrated precursor. Under the constraint of an array-type nano-confined microcavity, a controllable micro-explosion is synchronously triggered by a nanosecond laser. Combined with in-situ coating of hexagonal boron nitride and directional electric field modulation, the directional self-assembly of nanosecond-level highly stable two-dimensional black phosphorus is achieved, completely solving the industry pain points of easy oxidation and poor stability of traditional black phosphorus. The preparation cycle of this invention is reduced to less than 10 minutes, the product exhibits high room temperature carrier mobility, and a stable storage time in air of ≥30 days. It is 100% compatible with existing semiconductor production lines and is suitable for large-scale manufacturing in fields such as high-speed photodetectors, millimeter-wave devices, and biosensors.

Description

[0001] This invention belongs to the fields of two-dimensional semiconductor material manufacturing, atomic-level precision manufacturing, and optoelectronic device material manufacturing technology. Specifically, it relates to an in-situ stabilization method for atomic-level preparation of two-dimensional black phosphorus 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 black phosphorus in fields such as high-speed photodetectors, 6G millimeter-wave devices, quantum devices, and biosensors.

[0002] Two-dimensional black phosphorus (phosphene) is a two-dimensional direct bandgap semiconductor material with a graphene-like layered structure. The bandgap can be continuously tuned in the range of 0.3-2.0 eV by the number of layers, and it possesses ultra-high room temperature carrier mobility. Its excellent photoresponse and bipolar transport properties make it a core candidate material for 6G communication, infrared photodetector and quantum devices, and it has irreplaceable application value in the global high-end electronic information field.

[0003] Currently, the mainstream manufacturing technology for two-dimensional black phosphorus worldwide faces insurmountable industry pain points, specifically as follows:

[0004] Mechanical exfoliation: The mainstream method for preparing laboratory-grade two-dimensional black phosphorus globally. Using bulk black phosphorus single crystals as raw material, it involves manually exfoliating with adhesive tape to obtain few-layer black phosphorus nanosheets. This method can only achieve serial preparation of micron-sized samples, and its production capacity falls far short of the demands of industrial-scale mass production. More than twice as many times, making it completely impossible to scale up for application.

[0005] Liquid phase exfoliation: The mainstream preparation process for industrial-grade black phosphorus powder. Bulk black phosphorus is exfoliated by organic solvents using ultrasound. The resulting nanosheets have high defect density, uneven size, and uncontrollable number of layers. Furthermore, they are easily oxidized during the preparation process, and can only be used for low-end energy storage fillers, failing to meet the high-end application requirements of optoelectronic devices.

[0006] Chemical vapor deposition (CVD) can only produce small-sized, low-layer black phosphorus films. The growth temperature is as high as 600-900℃, and the growth pressure is as high as GPa. The equipment requirements are extremely high, the cost is huge, and it cannot achieve wafer-level uniform growth, making it completely unsuitable for industrial application.

[0007] The core critical weakness is that two-dimensional black phosphorus is extremely prone to oxidation and hydrolysis in the air. It undergoes significant degradation after being stored at room temperature for only a few hours, resulting in a severe decline in performance. Current technologies can only improve stability through post-processing coating and encapsulation, but cannot solve the oxidation problem at the source of preparation. This has become the biggest bottleneck restricting the development of the two-dimensional black phosphorus industry.

[0008] In summary, existing technologies have consistently failed to simultaneously achieve the five core objectives of wafer-level mass production, atomic-level layer control, in-situ stabilization, high quality and low defects, and low cost. This has become a major bottleneck restricting the large-scale development and high-end application of the global two-dimensional black phosphorus industry. Currently, there is no publicly available technological solution worldwide that can resolve all of these pain points.

[0009] The purpose of this invention is to overcome the above-mentioned defects of the prior art and provide an in-situ stabilized two-dimensional black phosphorus atomic-level manufacturing method and apparatus based on controllable micro-explosion. It breaks through the traditional technical logic of "synthesis first, coating later" in black phosphorus preparation. Using phosphorus-based energetic compounds as an integrated carrier of "phosphorus source + energy source", through the synergistic effect of nano-confinement, hexagonal boron nitride in-situ coating and synchronous field-controlled orientation technology, it achieves nanosecond-level high-stability two-dimensional black phosphorus orientation preparation. It completely solves the industry pain point of easy oxidation of black phosphorus from the source of preparation, and is 100% compatible with existing semiconductor wafer production lines.

[0010] The core inventive concept of this invention is as follows: using an integrated phosphorus source-energy energetic precursor system, a controllable micro-explosion is triggered synchronously 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 phosphorus atom raw materials required for black phosphorus growth; combined with a pre-positioned hexagonal boron nitride-coated confined template and a directional uniform electric field, the directional self-assembly of phosphorus atoms and the in-situ coating of hexagonal boron nitride atoms are completed simultaneously within the nanosecond time window of the explosion, achieving a one-step completion of "growth-passivation-stabilization", fundamentally solving the core pain point of easy oxidation and degradation of two-dimensional black phosphorus.

[0011] Compared with the prior art, the present invention has the following disruptive and beneficial technical effects: 1. Achieving in-situ stabilization from the source of preparation, completely solving the industry pain point of easy oxidation of black phosphorus: This invention achieves atomic-level in-situ coating of hexagonal boron nitride simultaneously with the growth of black phosphorus, isolating oxygen and water vapor. The prepared two-dimensional black phosphorus can be stored stably in the air for ≥30 days without significant oxidation, and the performance degradation is ≤5%. This completely solves the core problem that the post-encapsulation of existing technologies cannot completely isolate the environmental influence, clearing the biggest obstacle for the industrial application of black phosphorus.

[0012] 2. Achieving a breakthrough in production efficiency, completely overturning the industry's production cycle: Compared with the growth cycle of tens of hours in the traditional high-pressure CVD method, the production efficiency of this invention is increased by more than 1,000 times, compressing the two-dimensional black phosphorus 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.

[0013] 3. Atom-level precise layer control, high quality and low defects: This invention, through nanoscale confinement and electric field-directed manipulation, can precisely fabricate 1-5 layer few-layer structures or monolayer structures. The fabricated two-dimensional black phosphorus exhibits high room-temperature carrier mobility. Defect density It fully meets the high-end application requirements of high-speed photodetectors and 6G millimeter-wave devices.

[0014] 4. Energy consumption and manufacturing costs drop dramatically: This invention does not require GPa-level ultra-high pressure or long-term high-temperature heating. The comprehensive energy consumption is only less than 0.5% of that of the traditional high-pressure CVD method. The raw material atom utilization rate is close to 100%, and the comprehensive manufacturing cost can be reduced by more than 95%, completely breaking the cost barrier of the two-dimensional black phosphorus industry.

[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 in the existing semiconductor industry. There is no need to build new dedicated ultra-high voltage equipment. It can be directly upgraded on existing silicon-based and silicon carbide production lines in a modular manner, and industrialization can be achieved within 2-3 years without any technological gaps. At the same time, it can share a set of equipment with other two-dimensional material preparation processes to achieve "one machine for multiple productions" and greatly improve 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 black phosphorus layers / defects, atomic force microscopy (AFM) to test surface roughness, transmission electron microscopy (TEM) to observe the layer structure, Hall effect testing system to test carrier mobility, and X-ray photoelectron spectroscopy (XPS) to test the degree of oxidation.

[0019] Example 1: Fabrication of wafer-level few-layer black phosphorus thin films (for photodetectors)

[0020] This embodiment is used to prepare an 8-inch few-layer black phosphorus film for infrared photodetectors and 6G millimeter-wave devices. The specific steps are as follows: 1. Substrate pretreatment and preparation of encapsulated confinement template: An 8-inch silicon wafer 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 each microcavity was 3μm×3μm and the depth was 1μm. The inner wall of the microcavity was modified by plasma phosphorylation. A hexagonal boron nitride coating deposition site was reserved at the top of the microcavity as a directional template for black phosphorus growth and in-situ coating. 2. Preparation and Filling of Integrated Phosphorus Source-Energy Precursor: Using red phosphorus azide derivatives as the phosphorus-based energetic compound (phosphorus source and detonation source), and anhydrous n-hexane as the solvent, a homogeneous energetic precursor solution with a mass concentration of 5% was prepared by stirring in an anhydrous and oxygen-free glove box for 20 min; under a vacuum degree of... In a high vacuum environment, a micro-volume injection system is used to precisely fill all microcavities with the precursor solution, with a filling error of ≤0.1%. Simultaneously, a 20nm thick hexagonal boron nitride film is deposited using PECVD process to seal and in-situ cover the microcavity openings. 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... Achieving an ultimate vacuum, high-purity argon gas was introduced as a protective atmosphere, the substrate was heated to 400°C and held at that temperature, while simultaneously applying pressure to parallel plate electrodes on 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 two-dimensional black phosphorus: A 248nm nanosecond pulsed excimer laser was used to expose the entire 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 in the microcavities. The precursors decompose to generate highly active phosphorus atoms and nitrogen protective gas, while releasing instantaneous high temperature of 1000K and instantaneous high pressure of 5GPa. Under the synergistic constraints of phosphorylation template, uniform electric field and laser polarization, phosphorus atoms complete directional self-assembly in situ in the microcavities to generate few-layer two-dimensional black phosphorus that matches the template, and simultaneously achieve in-situ coating and passivation of hexagonal boron nitride. 5. In-situ post-processing: After the micro-explosion reaction, the substrate was subjected to millisecond-level low-temperature annealing using a 308nm excimer laser with a peak annealing temperature of 600℃ and an annealing time of 5ms to repair black phosphorus lattice defects. At the same time, high-purity argon gas with a purity of 99.9999% was introduced to perform a secondary passivation treatment at 150℃ for 30s. The gas generated by the reaction was extracted using a molecular pump system, and after cooling to room temperature, the substrate was removed to obtain the target 8-inch in-situ stabilized few-layer black phosphorus film.

[0021] Performance test results: The black phosphorus film prepared in this embodiment has a 2-3 layer few-layer structure, and the full width at half maximum (FWHM) of the characteristic peaks in the Raman spectrum is [data missing]. No defect peaks or oxidation peaks; room temperature carrier mobility reaches Defect density The surface roughness Ra is less than 0.3 nm. After being stored at room temperature in air for 30 days, the Raman spectrum shows no obvious oxidation peaks, and the carrier mobility decreases by ≤4%, with stability far exceeding that of black phosphorus prepared by existing technologies. The total time for single-wafer preparation is less than 8 minutes, and the comprehensive energy consumption is only 0.4% of that of the traditional high-pressure CVD method.

[0022] Example 2: Preparation of monolayer black phosphorus nanosheets (for quantum devices / biosensing)

[0023] This embodiment is used to prepare monolayer black phosphorus nanosheets for quantum devices and biosensors. The specific steps are as follows: 1. Substrate pretreatment and preparation of encapsulated confinement template: A sapphire substrate was selected, and an array of nano-confined microcavities were prepared on the substrate surface using MEMS technology. The planar size of a single microcavity was 1μm×1μm and the depth was 50nm. The inner wall of the microcavity was modified with phosphorylation. 2. Precursor Preparation and Filling: Using a phosphorus heterocyclic energetic compound as the phosphorus source and detonation source, and anhydrous toluene as the solvent, a homogeneous precursor solution with a mass concentration of 3% was prepared. Microcavity filling and in-situ sealing with a 10nm thick hexagonal boron nitride film were completed under high vacuum conditions. 3. Pretreatment: Heat the substrate to 350°C and apply... A vertical uniform electric field, with the vacuum level maintained at High-purity argon gas is introduced for protection; 4. Synchronous micro-explosion and monolayer black phosphorus molding: A 193nm nanosecond pulsed excimer laser was used to expose the entire substrate, with a laser energy density of [missing information]. With a pulse width of 15ns, it synchronously triggers a controllable micro-explosion in all precursors within the microcavities, completing the in-situ forming and coating of a single layer of black phosphorus in one step. 5. In-situ post-processing: Lattice defects were repaired by 500℃ millisecond-level laser annealing, and the substrate was passivated with argon gas at 120℃ for 20s. After the reaction gas was removed, the substrate was taken out to obtain in-situ stabilized monolayer black phosphorus nanosheets.

[0024] Performance test results: The black phosphorus prepared in this embodiment has a pure monolayer structure, no oxidation peak in the Raman spectrum, no obvious degradation after 20 days of storage in air, and a photoresponse of 1200 A / W. It can be directly used in infrared photodetectors, biosensors and quantum devices.

[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 in-situ stabilized two-dimensional black phosphorus atomic-level manufacturing device described in this invention;

[0027] Figure 2 This is a process flow diagram of the in-situ stabilized two-dimensional black phosphorus atomic-level manufacturing method described in this invention;

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

[0029] Figure 4 This is a schematic diagram illustrating the principle of controllable micro-explosion in-situ growth of two-dimensional black phosphorus 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 phosphorus atoms; 13-Phosphine phosphide growth template; 14-Precursor filling and in-situ coating system; 15-Wafer-level laser synchronous triggering system.

Claims

1. A method for in-situ stabilization of two-dimensional black phosphorus at the atomic level based on controllable micro-explosion, characterized in that, Includes the following steps: S1 Substrate pretreatment and preparation of encapsulated confinement template: A conductive substrate is selected as the growth substrate, and an array of nano-confined microcavities are prepared on the substrate surface. The inner wall of the nano-confined microcavities is modified by phosphorylation, and a hexagonal boron nitride coating deposition site is reserved at the top of the microcavities as a directional template for two-dimensional black phosphorus growth and in-situ coating. S2 Phosphorus Source-Energy Integrated Precursor Preparation and Filling: Using phosphorus-based energetic compounds as the phosphorus source and initiation source, dopant elements are added as needed to prepare homogeneous energetic precursors; under vacuum conditions... In a high vacuum environment of Pa, the energetic precursor is precisely filled into the nano-confined microcavity, and a hexagonal boron nitride coating layer is simultaneously deposited to seal and in-situ coat the opening of the microcavity. S3 Pre-field control and pre-temperature control: The filled substrate is placed in the vacuum reaction chamber and heated to the pre-temperature control range of 200-500℃. At the same time, a directional uniform electric field perpendicular to the substrate surface is applied to the upper and lower sides of the substrate, and high-purity argon gas is introduced into the vacuum reaction chamber as a protective atmosphere. S4 Controllable Micro-Explosion and Directional Growth of Two-Dimensional Black Phosphorus: A nanosecond pulsed excimer laser is used to expose the entire wafer surface of the substrate. The laser synchronously triggers nanosecond-level controllable micro-explosions in all energetic precursors within the nano-confined microcavities. The energetic precursors decompose to generate highly active phosphorus atoms and nitrogen protective gas, while simultaneously releasing instantaneous high temperatures of 600-1500K and instantaneous high pressures of 2-10GPa. Under the synergistic constraints of the phosphorylation template, uniform electric field, and laser polarization, phosphorus atoms complete in-situ directional self-assembly within the microcavities, generating monolayer / few-layer two-dimensional black phosphorus that matches the template, while simultaneously achieving in-situ encapsulation and passivation of hexagonal boron nitride. S5 In-situ post-processing: After the micro-explosion reaction is completed, the substrate is subjected to millisecond-level low-temperature laser annealing to repair lattice defects. At the same time, high-purity argon gas is introduced to perform secondary passivation treatment on the material. The protective gas generated by the reaction is removed through a vacuum system, and finally the target two-dimensional black phosphorus structure is obtained in-situ stabilized.

2. The manufacturing method according to claim 1, characterized in that, The phosphorus-based energetic compound is one or more of red phosphorus azide derivatives and phosphorus heterocyclic energetic compounds; the doping element precursor is an energetic complex of arsenic and antimony, used to prepare doped black phosphorus.

3. The manufacturing method according to claim 2, characterized in that, The homogeneous energetic precursor is an anhydrous and oxygen-free solution, the solvent is anhydrous toluene or anhydrous n-hexane, and the mass concentration of the phosphorus-based energetic compound is 2%-12%.

4. The manufacturing method according to claim 1, characterized in that, The conductive substrate is one of silicon wafer, sapphire, copper foil, and nickel foil. The depth of the nano-confined microcavity is 2nm-20μm, and the planar size of a single microcavity is 10nm-40μm. It is prepared by MEMS photolithography and dry etching processes.

5. The manufacturing method according to claim 4, characterized in that, In step S2, a 10-50 nm thick hexagonal boron nitride film is deposited using PECVD to seal and in-situ cover the microcavity opening, with the precursor filling amount error in a single microcavity ≤0.1%.

6. The manufacturing method according to claim 1, characterized in that, In step S3, the field strength of the directional uniform electric field is Vacuum degree of the vacuum reaction chamber .

7. The manufacturing method according to claim 1, characterized in that, In step S4, the wavelength of the nanosecond pulsed excimer laser is 193nm or 248nm, and the laser energy density is... The pulse width is 10-80ns, and the energy uniformity of the entire wafer in surface exposure is ≤0.5%.

8. The manufacturing method according to claim 1, characterized in that, In step S4, the instantaneous high temperature of the controllable micro-explosion is maintained for 10-60 ns, and the generated two-dimensional black phosphorus has a few-layer structure of 1-5 layers or a single-layer structure with a sheet size of 0.5-10 μm, while simultaneously achieving atomic-level in-situ coating of hexagonal boron nitride.

9. The manufacturing method according to claim 1, characterized in that, In step S5, the peak temperature of laser annealing is 400-800℃, the temperature of argon passivation is 80-180℃, the passivation time is 10-60s, and the purity of argon is ≥99.9999%.

10. The manufacturing method according to any one of claims 1-9, characterized in that, The prepared two-dimensional black phosphorus room temperature carrier mobility Stable in air for ≥30 days with no obvious oxidation, defect density .

11. A two-dimensional black phosphorus atomic-level manufacturing apparatus for implementing the manufacturing method according to any one of claims 1-10, characterized in that, include: The high-vacuum reaction chamber system is equipped with a high-precision substrate heating stage, a molecular pump pumping unit, and multiple gas pathways, achieving an ultimate vacuum level. ; The precursor filling and in-situ coating system includes a high-vacuum micro-liquid injection unit and a hexagonal boron nitride thin film deposition unit, which are used to complete the precise filling of energetic precursors and the in-situ coating and sealing of microcavities under high vacuum conditions. The electric field control system, including parallel plate electrodes and a high-precision high-voltage power supply, can output electric field strength. 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 low-temperature laser annealing module and an inert gas atmosphere control unit, is used for lattice repair and secondary passivation of two-dimensional black phosphorus, and can achieve millisecond-level laser annealing at 400-800℃ and argon passivation treatment at 80-180℃. 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.

Images