Wafer-level molybdenum disulfide monolayer material and preparation method thereof, and mocvd system

Abstract

The application belongs to the technical field of advanced semiconductor material preparation, and particularly relates to a wafer-level molybdenum disulfide monolayer material and a preparation method and a MOCVD system thereof. The application realizes wafer-level large-area uniform growth and accurate morphology control. Through space-time decoupling control of growth kinetics, the crystal domain size of MoS2 can be adjusted in the range of 10-200 microns on a 4-6 inch substrate, and the grain boundary density is reduced by more than one order of magnitude, which lays a foundation for preparing high-performance single-crystal devices. On this basis, a wafer-level large-area uniform monolayer MoS2 film is successfully prepared. An optical microscope image shows that the film is continuous, complete and has a coverage of 95%; atomic force microscope test shows that the thickness uniformity of the film is excellent, the roughness is 1.2 nm, and the deviation is less than or equal to ±0.3 nm. High-quality crystal structure and electrical properties are obtained, and the material has excellent crystal quality and electrical properties.

Description

Technical Field

[0001] This invention belongs to the field of advanced semiconductor material preparation technology, specifically relating to a wafer-level molybdenum disulfide monolayer material and its preparation method, as well as an MOCVD system. Background Technology

[0002] Two-dimensional transition metal chalcogenides (TMDCs) have become key candidate materials for next-generation semiconductor devices due to their unique band structure and excellent electrical and optical properties. Among them, molybdenum disulfide (MoS2) is a typical representative, showing great application potential in transistors, sensors, and photodetectors. To realize its industrial application, it is crucial to develop wafer-level, high-quality, uniform, and controllable monolayer MoS2 material growth technology.

[0003] Currently, the main methods for preparing MoS2 include mechanical exfoliation, chemical vapor deposition (CVD), and metal-organic chemical vapor deposition (MOCVD). Among these, MOCVD technology is considered one of the most promising routes for wafer-level two-dimensional material preparation due to its advantages such as large-area uniformity, controllable growth rate, ease of doping, and large-scale production. However, existing MOCVD technologies still have some problems when it comes to wafer-level MoS2 monolayer growth. One issue is that traditional MOCVD systems use a monolithic cavity heating method, which is easily affected by thermal field distribution, gas flow uniformity, and precursor concentration gradients. This leads to spatial fluctuations in the uniformity of MoS2 layers, crystal quality, and electrical properties on large-area substrates, making it difficult to meet device consistency and yield requirements. Secondly, the precision of nucleation and growth control is insufficient. The growth process of MoS2 involves multiple stages, including nucleation, domain merging, and epitaxy. Traditional MOCVD process parameters, such as temperature, pressure, and gas flow rate, are mostly macroscopically adjustable, lacking precise temporal and dimensional control over the microscopic processes of nucleation density, grain boundary formation, and defect state density, affecting the continuity and electrical properties of monolayer materials. Furthermore, existing technologies typically separate material growth and device patterning into independent steps, relying on subsequent microfabrication processes such as photolithography and etching. This is not only cumbersome and costly but also introduces interface damage, contamination, and edge state problems, significantly impacting the performance of atomically thin monolayer materials. It is evident that existing MOCVD methods cannot simultaneously achieve high-quality growth and precise control of wafer-level uniformity. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a wafer-level molybdenum disulfide monolayer material, its preparation method, and an MOCVD system. The specific technical solution is as follows.

[0005] A method for preparing wafer-level molybdenum disulfide monolayer material based on metal-organic chemical vapor deposition includes the following steps: The precursor gas source, molybdenum hexacarbonyl vapor, and diethyl sulfide vapor were introduced into the reaction chamber at an equal volume ratio and a flow rate of 20 sccm to 50 sccm, respectively. Argon gas was introduced at a flow rate of 900 sccm to 1000 sccm. The temperature was increased to 870°C at a rate of 10°C / min to 20°C / min and held at standard atmospheric pressure for 40 min to 45 min to allow the precursor vapor to grow on the substrate surface. The heating rate was controlled to avoid thermal shock to the substrate. After growth is complete, the precursor gas supply is stopped, argon gas is kept flowing, and the temperature is reduced to room temperature at a rate of 1℃ / min to 3℃ / min. The cooling rate is controlled to prevent cracking of the wafer-level molybdenum disulfide monolayer. After cooling, a substrate with wafer-level molybdenum disulfide monolayer material is obtained.

[0006] In another preferred embodiment, the temperature of the hexacarbonyl molybdenum vapor is 80°C to 120°C; The temperature of the diethyl sulfide vapor is 50℃~80℃.

[0007] In another preferred embodiment, the substrate forms an angle of 30° to 45° with the precursor gas source direction. This angle enables uniform film growth and improves the uniformity of the wafer-level molybdenum disulfide monolayer material.

[0008] In another preferred embodiment, before the precursor gas source is introduced, argon gas is introduced to purge the air in the reaction chamber.

[0009] The second aspect of the present invention provides a wafer-level molybdenum disulfide monolayer material obtained by the preparation method described above.

[0010] In another preferred embodiment, the domain size of the wafer-level molybdenum disulfide monolayer material is between 10 μm and 200 μm.

[0011] The third aspect of the present invention provides a metal-organic chemical vapor deposition system for the aforementioned metal-organic chemical vapor deposition method, comprising a precursor bubbling device, a carrier gas supply unit, and a heating reaction chamber; the inlet of the heating reaction chamber is provided with a gas delivery system; the gas delivery system is used to control the precursor gas source and the flow rate of argon gas entering the heating reaction chamber. The precursor bubbling device contains three independent bubblers, which respectively contain molybdenum hexacarbonyl, diethyl sulfide, and decaethyltetranitrogen as reaction precursors; each bubbler is connected to the inlet of the heated reaction chamber through an independent carrier gas pipeline; The carrier gas supply unit includes hydrogen, argon, and oxygen. Argon is supplied in two streams: one directly enters the heated reaction chamber, and the other acts as a carrier gas, flowing through each bubbler to transport the precursor vapor to the reaction area. Oxygen promotes growth; a small amount of O2 can significantly increase grain size, while excessive O2 or prolonged exposure time can over-etch the primary crystal, leading to a reduction in crystal size. As a chemical etchant, it removes unstable nuclei to reduce nucleation density and prevents poisoning of the MoO3 precursor, ensuring high chemical activity.

[0012] Hydrogen: Promotes growth; small amounts of H2—by reacting with carbon to form organic gases—eliminate carbon pollution generated during growth and accelerate MoS2 growth by promoting precursor vaporization. As the gas flow rate further increases, the size of monolayer MoS2 decreases significantly, and bilayer MoS2 emerges.

[0013] Argon: as a carrier gas, it transports precursors and maintains a stable flow rate; as a dilution gas, it regulates the reaction rate and improves the uniformity of the flow field; it serves as a protection and purging agent, cleaning the system and providing safety protection; and it regulates the thermal field by controlling thermal conduction. A base is provided in the heating reaction chamber, and the base is placed at an angle of 30-45° to the direction of the precursor gas source. A gas mixing chamber is provided at the entrance of the heating reaction chamber, so that the precursor vapor and the reaction gas are fully mixed and uniformly delivered to the substrate surface.

[0014] The heating reaction chamber, centered on a common tubular furnace, utilizes modular integration to reduce equipment setup costs to less than one-third of traditional dedicated MOCVD systems, while maintaining system scalability and rapid reconfiguration capabilities to meet diverse R&D needs. It achieves near-total automation and highly repeatable process control: the central control system enables "one-click" fully automated operation from environment setup and programmed growth to safe cooling, with process repeatability deviations ≤3%, significantly reducing human error and ensuring the reliability of experimental results. It provides an efficient process development and optimization platform: intelligent software supports rapid editing of complex formulations and multi-parameter automated experiments, shortening the traditionally weeks-long process optimization cycle to within days, significantly accelerating the research process of new material systems, doping processes, and heterostructures. It possesses excellent process safety and stability: integrating pressure monitoring, gas leak alarms, and temperature-airflow interlock protection mechanisms, the system can operate continuously and stably for more than a certain growth cycle without major maintenance, ensuring the feasibility of long-term R&D and small-batch trial production.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention achieves wafer-level large-area uniform growth and precise morphology control. Through spatiotemporal decoupling control of growth kinetics, precise control is first achieved at the material morphology and nucleation levels. Heating to 870℃ at a rate of 10℃ / min~20℃ / min and holding at standard atmospheric pressure for 40min~45min enables tunable growth of MoS2 domain sizes within the range of 10μm~200μm on a 6-inch substrate, reducing grain boundary density by more than an order of magnitude, laying the foundation for the fabrication of high-performance single-crystal devices. Based on this, a wafer-level large-area uniform monolayer MoS2 film was successfully fabricated. Optical microscopy images show that the film is continuous, intact, and has a coverage of 95%; atomic force microscopy (AFM) tests show excellent thickness uniformity and a roughness of 1.2nm with a deviation ≤±0.3nm. High-quality crystal structure and electrical properties were obtained, and the material exhibits excellent crystal quality and electrical properties. Transmission electron microscopy (TEM) analysis confirmed that the grown monolayer MoS2 has a highly ordered atomic arrangement and a complete 2H crystal structure. Photoluminescence (PL: 1.8 eV) spectra exhibit sharp and intense exciton emission peaks, further confirming its excellent optical quality and low defect density. Raman spectroscopy characterization shows that the peak positions of its characteristic peaks E12g: 383 / cm and A1g: 402 / cm fluctuate within a wafer-wide range of ≤1.5 cm⁻¹. -1 These results fully meet the stringent requirements for material consistency in high-performance devices. Attached Figure Description

[0016] Figure 1 This diagram shows the growth of molybdenum disulfide. Diagrams A and B show the growth of different parts of the molybdenum disulfide.

[0017] Figure 2 The image shows the results of the Raman spectroscopy test.

[0018] Figure 3 This is a graph showing the results of the mapping test.

[0019] Figure 4 This is a graph showing the results of the mapping test.

[0020] Figure 5 This is the photoluminescence spectrum of PL.

[0021] Figure 6 The images show the results of atomic force microscopy (AFM), where A and B represent the results of AFM at different magnifications.

[0022] Figure 7 The figure shows the growth of molybdenum disulfide prepared using the original data; A to G in the figure are the growth figures corresponding to the repeatability experiments.

[0023] Figure 8This is a schematic diagram of the process of a metal-organic chemical vapor deposition system. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0027] Unless otherwise specified, the experimental methods described in the following embodiments are conventional methods; unless otherwise specified, the reagents and materials are commercially available.

[0028] This invention aims to overcome the core problems of existing MOCVD technology in the growth of molybdenum disulfide (MoS2) monolayer materials at the wafer level, such as high temperature limitation, poor uniformity, and cumbersome process. It provides an MOCVD system and its supporting process method that can achieve low-temperature, large-area, uniform, and high-quality MoS2 monolayer growth.

[0029] Based on this, the present invention is designed from the following aspects: First, a new paradigm for wafer-level uniformity control has been established in terms of material quality. By integrating a multi-zone independent heating system and a gas homogenization distribution device, precise and coordinated control of the temperature field and reactant flow field on 4- to 8-inch wafer substrates is achieved. This innovative design controls the temperature deviation between the wafer edge and center within ±5℃, and achieves a precursor concentration distribution uniformity of over 95%, thereby ensuring the thickness uniformity, crystal quality consistency, and electrical performance stability of the MoS2 monolayer material at the wafer scale.

[0030] Second, in terms of system construction, precise and controllable delivery of the all-gaseous precursor has been achieved. This invention innovatively employs a fully gaseous precursor delivery scheme, utilizing independently controlled multi-channel high-precision mass flow controllers to achieve real-time and precise control of the flow rates of molybdenum hexacarbonyl molybdenum vapor and sulfur diethyl sulfide gas. Compared to traditional liquid-source bubbling delivery methods, this system avoids the problem of precursor partial pressure fluctuations and can achieve precise adjustment of the gas ratio within millisecond response time, providing a crucial guarantee for atomic-level precision material growth.

[0031] Third, it creates a new spatiotemporal decoupling method for growth dynamics in the process control dimension. By decoupling the nucleation, domain growth, and merging processes in time and space, precise control of the growth kinetics of two-dimensional materials is achieved. The system can independently optimize key parameters at each stage: controlling nucleation density at low temperatures, regulating domain size at heating temperatures, and promoting grain boundary fusion at isothermal temperatures. This "staged optimization" strategy enables the domain size of monolayer MoS2 to reach the hundreds of micrometers scale, while reducing the grain boundary density by more than an order of magnitude.

[0032] Fourth, an intelligent and scalable process development platform has been built in terms of system integration. Based on modular design principles and industrial automation control technology, this system not only achieves semi-automation of the entire process from substrate loading and process execution to sample removal, but also constructs an open process development environment. Researchers can quickly edit complex process formulations through a graphical interface. The system supports the automatic execution and data acquisition of multi-parameter orthogonal experiments, shortening the traditional process optimization cycle of several weeks to several days, greatly accelerating the research process of new material systems.

[0033] The flowchart of the MOCVD system is shown below, and its specific components are as follows.

[0034] Device components: 1. Core reaction unit heating reaction chamber: Modified tubular furnace system This unit serves as the heating reaction chamber for the entire system and is a modified conventional laboratory tube furnace. The main structure adopts a standard horizontal tube furnace, with its original quartz or corundum reaction tubes directly serving as the growth chamber for the MOCVD process.

[0035] The key modification is the multi-functional inlet flange: replacing the original simple inlet, it is designed as a standardized flange structure integrating multiple gas input interfaces, thermocouple through holes, and optional observation windows, achieving a quick and reliable sealed connection with the gas circuit system. The multi-functional inlet flange was purchased from Wuhan Yaoyang Gas Company.

[0036] Optimized sample carrier: Design a special quartz boat or sample holder for the growth characteristics of two-dimensional materials. Through manual calibration, set a visual physical positioning scale on the outside of the furnace tube, and design a matching quartz carrier with positioning slots to ensure that the center of the substrate is strictly aligned with the center of the thermal field each time it is loaded.

[0037] Temperature field calibration and standardization: The temperature field of the tube furnace is systematically calibrated to establish a database of accurate correspondence between the furnace display temperature and the actual substrate temperature, providing a reliable basis for setting the temperature parameters of the process formulation.

[0038] 2. Carrier gas supply unit This unit, serving as the system's "material conveying and dispensing system," is responsible for providing a precise, stable, and programmable gaseous environment for the precursor reaction process.

[0039] Includes: a gas source interface for connecting carrier gas Ar, N2, and reaction gas.

[0040] The precursor evaporation device consists of three independent bubblers: each with independent temperature control function, used to heat and vaporize the liquid metal organic source to ensure stable steam output.

[0041] Precision control components: A high-precision mass flow controller is used to achieve closed-loop control of the gas flow rate of each channel; rapid on / off operation of gas is performed through solenoid valves or pneumatic valves.

[0042] Gas mixing chamber: Located inside the heated reaction chamber, it achieves uniform mixing of multiple gases before delivering them to the reaction unit, ensuring a consistent reaction atmosphere.

[0043] Quick connection mechanism: The entire gas circuit unit is connected to the inlet flange of the core reaction unit through standardized quick connectors, supporting "plug and play" operation, which facilitates quick disassembly and assembly of the system, daily maintenance, and flexible reconfiguration of the gas circuit structure.

[0044] 3. Core functional unit for achieving automated control of the entire process and synchronous acquisition of key data This unit serves as the "intelligent control center" of the system, responsible for coordinating the collaborative operation of almost all hardware modules to achieve advanced automated execution and closed-loop management of the entire process.

[0045] Hardware core configuration: It adopts an industrial control computer as the main control platform, equipped with a multi-channel data acquisition card, a digital input / output control card and a relay output module, to build a complete signal processing and execution control link.

[0046] Multi-system integration and linkage methods: Linked with the reaction unit: Through communication interface or analog signal transmission, the heating program of the tubular furnace can be remotely set, started and paused, and the furnace temperature status can be monitored in real time.

[0047] Linkage with the gas circuit unit: The target values ​​of each mass flow controller are precisely set by analog output signals, and the opening and closing actions of solenoid valves or pneumatic valves are controlled by digital signals to achieve programmed control of gas delivery timing and flow curve.

[0048] Safety monitoring and interlocking: Integrates pressure sensor signals to monitor the pressure status of the reaction chamber in real time; supports connection to gas leak detection and alarm devices to form a process safety interlocking protection mechanism.

[0049] Intelligent Software Platform: The system is equipped with dedicated control software running on an industrial computer, and has the following functions: Process recipe editing: Users can flexibly edit the complete "process recipe" in the graphical interface to achieve synchronous arrangement and timing coordination of temperature curves and gas flow curves.

[0050] Automated process execution: Supports one-click start of fully automated growth process. The software coordinates the actions of each unit according to the formula instructions, realizing almost unmanned operation from environmental preparation, growth reaction to safe cooling.

[0051] Data recording and traceability: Real-time acquisition and storage of key process parameters such as temperature, flow rate, and pressure, generating complete process data logs to support subsequent data analysis, process optimization, and experimental reproduction.

[0052] The following section details a wafer-level molybdenum disulfide monolayer material, its preparation method, and the MOCVD system. The MOCVD system is described below. Figure 8 As shown.

[0053] 1. System Assembly and Initialization Hardware Connection: The modular gas delivery unit is reliably connected to the inlet flange of the modified tubular furnace reaction unit via a standardized quick-connect interface. The tubular furnace is then connected to the central control unit via a communication cable.

[0054] Air tightness check: Close all valves and pressurize the entire gas path and reaction chamber with inert gas Ar or N2. In this embodiment, argon is used. Check the system's airtightness with a pressure gauge or leak detector to ensure there is no leakage.

[0055] Software Configuration and Process Recipe Editing: Start the central control software and create or load a process recipe. In this scheme, two core programs are simultaneously programmed:

[0056] Temperature program: Sets the heating rate, target temperature, isothermal time, and cooling curve for the tube furnace. Gas program: Sets the on / off time points, target flow rates, and variation curves for each gas stream (carrier gas, reactant gas, precursor).

[0057] Substrate pretreatment and loading: The target sapphire substrate was cleaned using standard methods. In this embodiment, ultrasonic cleaning with deionized water was performed, followed by precursor spin coating and drying. The treated substrate was then placed on a dedicated sample carrier inside a tube furnace, ensuring it was centered within the calibrated isothermal zone.

[0058] 2. Reaction environment setup and precursor adsorption Cavity Purification: Close the furnace and start the vacuum system (if equipped) or use a high-purity inert gas (such as argon or nitrogen) to purge the reaction pipeline and cavity at a high flow rate to effectively remove air, moisture, and other volatile impurities from the cavity until the system pressure reaches the preset process baseline value or the set purging time is completed. In this embodiment, argon is used for purging.

[0059] Establishing a stable growth environment: After chamber purification, without additional preheating, the necessary gaseous environment for growth is established directly at room temperature. The central control unit, based on a preset gas program, semi-automatically controls each gas path to perform the following operations:

[0060] First, open the carrier gas and dilution gas valves and adjust the gas flow rate to 1000 sccm to stabilize the pressure inside the reaction chamber within the growth pressure range set by the process.

[0061] Subsequently, according to the timing logic, the heating temperature is initiated and controlled to the set value. Then, the corresponding open valve is opened to introduce precisely measured metal-organic precursor vapor into the reaction chamber. During this stage, the precursor molecules gradually adsorb onto the substrate surface at room temperature and form a relatively uniform coating layer.

[0062] System status confirmation: The control software monitors and confirms in real time that the pressure and gas flow parameters have reached and stabilized within the set range, indicating that the gas atmosphere before growth has been successfully established and the system is ready to enter the next stage.

[0063] 3. Programmed growth This stage is entirely controlled automatically by the preset process formula and is the core of the method.

[0064] Triggering growth conditions: Once the gas atmosphere is stable, the software will trigger growth based on the formula logic.

[0065] Issue a synchronization command: Heating command: The command instructs the tube furnace to change to a higher “growth temperature” from the start, according to the preset growth temperature curve (such as rapid or gradient heating).

[0066] Gas switching / adjustment command: Simultaneously, based on the needs of the material system, the flow rates of the reaction gases molybdenum hexacarbonyl and diethyl sulfide are automatically adjusted to the required proportions for growth, and the flow rate of the precursor may be fine-tuned.

[0067] Isothermal Growth: Once the set growth temperature is reached, the system enters the isothermal growth stage. During this stage, the central control unit strictly maintains the set temperature and the stable flow rates of each gas. The adsorbed precursor decomposes at high temperature and undergoes a chemical reaction on the substrate surface, achieving large-area growth of molybdenum disulfide. The isothermal time depends on the thickness of the target material layer.

[0068] Real-time monitoring: Throughout the growth process, the control software interface displays all sensor data—temperature, flow rate, and pressure—in real time, allowing operators to monitor the process. If an integrated in-situ monitoring port is available, the growth status can be observed.

[0069] The specific parameters in the above steps are as follows: Temperature parameters: Heating rate 10~20℃ / min to avoid thermal shock to the substrate; growth temperature 870℃; holding time 40min. Cooling rate 1~3℃ / min to prevent film cracking.

[0070] Gas parameters: Argon carrier gas flow rate 1000 sccm, with a stable gas flow throughout.

[0071] The ratio of reactant gases is 1:1.8 (volume ratio of hexacarbonyl molybdenum vapor to diethyl sulfide vapor).

[0072] Gas partial pressure: 75 Pa. Low gas pressure environment is conducive to uniform film growth.

[0073] Precursor parameters: hexacarbonyl molybdenum source temperature: 80~120℃; diethyl sulfide source temperature: 50~80℃; Precursor carrier gas flow rate: 20~50sccm, with independent control of two precursor steam delivery paths.

[0074] Substrate parameters: The substrate is placed at an angle of 30~45° to the airflow direction of the precursor to improve film uniformity.

[0075] The specific operation process is as follows: Equipment preparation and substrate pretreatment: Check the airtightness of the MOCVD system to ensure there are no leaks.

[0076] The substrate is cleaned in potassium hydroxide solution to remove surface impurities, dried with nitrogen, and then treated in a plasma cleaner to enhance surface adhesion.

[0077] Precursor and gas preparation: Molybdenum hexacarbonyl and diethyl sulfide were placed into sealed source bottles at a volume ratio of 1:1.8, and the source bottle temperature was set to 40℃; the carrier gas and reaction gas pipelines were connected, and the flow meters were adjusted to the set parameters, specifically: carrier gas Ar flow rate: 1000 sccm; reaction gas H2 flow rate: 500 sccm; argon gas was first introduced to purge the air from the system for 15 minutes.

[0078] Cooling and Sample Removal: After growth, the precursor gas source was turned off, while argon gas was kept flowing, and the temperature was lowered to room temperature at a rate of 3℃ / min. After the system was completely cooled, all gas sources and power sources were turned off, the substrate was removed, and the preparation of the molybdenum disulfide thin film was completed.

[0079] The properties of the wafer-level molybdenum disulfide monolayer material obtained by the above method were measured, and the results are as follows: Figures 1-6 As shown.

[0080] Figure 1 The molybdenum disulfide growth obtained under the above conditions can be observed to have a large area of ​​relatively uniform film, in which the dark part is the sapphire substrate and the light part is the molybdenum disulfide film.

[0081] Figure 2 Raman spectroscopy was used to identify a sample as molybdenum disulfide by detecting a specific peak value.

[0082] Figure 3 The mapping test was used to examine the flatness and uniformity of the molybdenum disulfide thin film sample. Higher uniformity indicates a more consistent color.

[0083] Figure 4 The mapping test was used to examine the flatness and uniformity of the molybdenum disulfide thin film sample. Higher uniformity indicates a more consistent color.

[0084] Figure 5 To determine whether a sample is monolayer, bilayer, multilayer, or bulk molybdenum disulfide, specific peak values ​​in the photoluminescence (PL) spectrum are used to identify it. Monolayer MoS2 exhibits a direct bandgap, generating a strong PL signal (A exciton 1.80-1.83 eV, B exciton 1.95 eV). From... Figure 5 It can be seen that the prepared material is a single-layer molybdenum disulfide film.

[0085] Figure 6 To observe the atomic arrangement on the surface of molybdenum disulfide (MoS2) using atomic force microscopy (AFM), the AFM height of monolayer MoS2 is typically 0.6 nm to 1.2 nm. Heights between 2 nm and 3 nm indicate bilayers. Heights above 3 nm are mostly multilayers or bulk structures. The prepared monolayer MoS2 film was initially determined directly based on the height value. The original parameters are shown in Table 1, and the results are as follows: Figure 7 As shown.

[0086] Table 1 Original Parameters from Figure 7 Compared with the molybdenum disulfide prepared using the method of this invention, it can be seen that the molybdenum disulfide prepared using the original data shows a clear and irregular distribution of small triangles and regional multilayer-like structures; the white bright spots are more obvious and the crystal orientation is not obvious or unique, the coverage is low, the uniformity is poor, and the quality is poor.

[0087] 3. Growth Termination and Safe Cooling Termination reaction: After the isothermal growth phase, the software automatically executes the termination sequence in the formula. First, shut off the heating of the precursor evaporator and its carrier gas, and stop supplying the metal-organic source.

[0088] Then, shut off the reaction gas flow. Maintain or adjust the carrier gas flow to purge the reaction tube and remove any remaining reactants and byproducts from the chamber.

[0089] Programmed cooling: Under inert atmosphere purging, the software instructs the tubular furnace to begin cooling according to a preset cooling curve (such as natural cooling or programmed cooling).

[0090] The system ensures that the substrate remains under inert gas protection until the temperature drops to a safe threshold (e.g., below 200°C) to prevent oxidation of the high-temperature sample.

[0091] System Reset and Sampling: When the software detects that the furnace temperature has dropped to a safe level (e.g., <60℃), it automatically closes all gas valves and stops data recording. The operator can then fill the chamber with inert gas to atmospheric pressure, open the tube furnace, and remove the sample with the grown two-dimensional material.

[0092] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for producing a wafer-level monolayer of molybdenum disulfide material based on a metal-organic chemical vapor deposition method, characterized by, Includes the following steps: The precursor gas source, molybdenum hexacarbonyl vapor, and diethyl sulfide vapor were introduced into the reaction chamber at a volume ratio of 1:1 to 1.8 and a flow rate of 20 sccm to 50 sccm, respectively. Argon gas was introduced at a flow rate of 900 sccm to 1000 sccm. The temperature was increased to 870°C at a rate of 10°C to 20°C to 20°C to 20°C, and held at standard atmospheric pressure for 40 to 45 minutes to allow the precursor vapor to grow on the substrate surface. After growth is complete, the precursor gas supply is stopped, argon gas is kept flowing, and the temperature is reduced at a rate of 1℃ / min to 3℃ / min to obtain a substrate with a wafer-level molybdenum disulfide monolayer material grown on it.

2. The method of claim 1, wherein the metal-organic chemical vapor deposition method is a metal-organic chemical vapor deposition method for preparing a single layer of molybdenum disulfide material on a wafer, characterized by, The temperature of the hexacarbonyl molybdenum vapor is 80℃~120℃; The temperature of the diethyl sulfide vapor is 50℃~80℃.

3. The method for preparing wafer-level molybdenum disulfide monolayer material based on metal-organic chemical vapor deposition according to claim 1, characterized in that, The substrate is at an angle of 30-45° to the direction of the precursor gas source.

4. The method of claim 1, wherein the metal-organic chemical vapor deposition method is a metal-organic chemical vapor deposition method for preparing a single layer of molybdenum disulfide material on a wafer, characterized by, Before the precursor gas source is introduced, argon gas is also introduced to purge the air in the reaction chamber.

5. A wafer-level molybdenum disulfide monolayer material obtained by the preparation method described in any one of claims 1 to 4.

6. The wafer level molybdenum disulfide monolayer material of claim 5, wherein, The domain size of the wafer-level molybdenum disulfide monolayer material is between 10 μm and 200 μm.

7. A MOCVD system for preparing the metal organic chemical vapor deposition process of claim 5, characterized by, Includes a precursor bubbling device, a carrier gas supply unit, and a heated reaction chamber; The inlet of the heating reaction chamber is equipped with a gas delivery system; the gas delivery system is used to control the precursor gas source and the flow rate of argon gas into the heating reaction chamber. The precursor bubbling device contains three independent bubblers, each containing molybdenum hexacarbonyl, diethyl sulfide, and argon gas as reaction precursors; each bubbler is connected to the inlet of the heated reaction chamber via an independent carrier gas pipeline. The carrier gas supply unit includes hydrogen, argon and oxygen; the argon is divided into two paths: one path is directly introduced into the heating reaction chamber, and the other path is used as a carrier gas to flow through each bubbler to transport the precursor vapor to the reaction area. A base is provided in the heating reaction chamber, and the base is placed at an angle of 30-45° to the direction of the precursor gas source. A gas mixing chamber is provided at the entrance of the heating reaction chamber, so that the precursor vapor and the reaction gas are fully mixed and uniformly delivered to the substrate surface.

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