A tube furnace with reaction isolation function

Abstract

This invention discloses a tubular furnace with reaction isolation function. The tubular furnace includes a furnace tube compartment, a raw material compartment communicating with the furnace tube compartment, and a raw material boat lifting system. The raw material compartment contains a raw material boat connected to the raw material boat lifting system. The raw material boat is raised from the raw material compartment to the furnace tube compartment or lowered from the furnace tube compartment to the raw material compartment by the lifting system. This invention's tubular furnace achieves uniform and stable supply of precursor steam and precise "hard-switching" control of the reaction process through the synergistic effect of multi-channel uniform carrier gas distribution, airtight vertical lifting of the raw material boat, and a rapidly opening and closing insert-type baffle valve.

Description

Technical Field

[0001] This invention belongs to the field of material preparation equipment technology, specifically relating to chemical vapor deposition (CVD) tube furnaces, and more particularly to a tube furnace with reaction isolation function. Background Technology

[0002] In the preparation of high-quality semiconductor thin films in high-temperature tube furnaces (especially CVD furnaces), the stable and uniform delivery of precursor raw materials and the precise control of the reaction process are two key challenges. For precursors with high evaporation temperatures and low vapor pressures (such as certain metal halides), the traditional single-point carrier gas carrying method is prone to forming localized saturated vapors in the raw material area, resulting in unstable precursor concentrations and uneven spatial distribution in the gas flow transported to the growth zone. This is one of the important reasons for the uneven thickness and composition of large-area thin films.

[0003] A more challenging issue is controlling the reaction termination. When growth ends, simply stopping heating or shutting off the carrier gas cannot instantly cut off the precursor supply, as a large amount of raw material continues to evaporate from the high-temperature raw material boat and its surrounding area. This "exhaust gas" effect leads to unintentional deposition, contaminating the substrate and cavity, severely impacting the film's interface clarity and device performance consistency. Existing technologies employ rapid cooling methods using an integrated furnace, which are energy-intensive, time-consuming, and subject to severe thermal stress that can damage the film or equipment.

[0004] Therefore, developing a subsystem that can achieve uniform transport of precursors and physically and quickly isolate the raw material zone from the reaction zone is crucial for improving the uniformity, repeatability, and controllability of tubular furnace processes. Summary of the Invention

[0005] Purpose of the invention: In order to overcome the defects of uneven raw material delivery and difficulty in instantaneous termination of reaction in existing tubular furnaces, the present invention aims to provide a tubular furnace with high controllability and reaction isolation function.

[0006] To achieve the above objectives, the technical solution for the tubular furnace provided by this invention is as follows:

[0007] The present invention provides a tubular furnace, including a furnace tube compartment, a raw material compartment communicating with the furnace tube compartment, and a raw material boat lifting system; wherein, the raw material compartment is provided with a raw material boat connected to the raw material boat lifting system; the raw material boat is raised from the raw material compartment to the furnace tube compartment or lowered from the furnace tube compartment to the raw material compartment under the action of the raw material boat lifting system.

[0008] The raw material compartment is equipped with an observation window for changing raw materials.

[0009] The raw material boat includes a raw material container, a gas channel, and a perforated heat insulation column. The gas channel runs through the bottom of the raw material container and is connected to it. The perforated heat insulation column surrounds the gas channel.

[0010] The transmission mechanism of the raw material boat lifting system is a screw and nut mechanism, and it is equipped with an infrared or photoelectric sensor limiter.

[0011] The raw material boat lifting system includes a threaded rod, a motor, a bellows, an upper plate, a lower plate, and a nut plate. The upper end of the threaded rod is mounted on the upper plate, and the lower end of the threaded rod is fixed to the lower plate via the motor. The nut plate is sleeved on the threaded rod, and the motor is connected to the threaded rod via a coupling.

[0012] The tubular furnace also includes a heating coupler assembly, which is wrapped around the furnace tube compartment. The heating coupler assembly includes several parallel heating couplers, an electrothermal coupler inserted into each heating coupler, and a heat insulation layer covering each heating coupler.

[0013] The furnace tube chamber is divided into several temperature zones. During the reaction, the substrate in the furnace tube chamber is located in one temperature zone, while the raw material boat in the furnace tube chamber is located in another temperature zone. The two temperatures are different.

[0014] A baffle valve is installed between the furnace tube compartment and the raw material compartment. The baffle valve is used for the connection and isolation between the furnace tube compartment and the raw material compartment.

[0015] The furnace tube compartment is equipped with a suspension wire, the top of which is fixed to the top of the furnace tube compartment, and the bottom of which is fixed to a substrate holder.

[0016] The furnace tube compartment is equipped with a first airtight assembly at the top, which includes a first mixing chamber flange that is sealed to the top of the furnace tube compartment, a first inlet pipe and a first outlet pipe that are respectively connected to the first mixing chamber flange; the raw material compartment is equipped with a second airtight assembly at the bottom, which includes a second mixing chamber flange that is sealed to the bottom of the raw material compartment, a second inlet pipe, a second outlet pipe and a pump connection pipe that are respectively connected to the second mixing chamber flange.

[0017] This invention provides a method for preparing materials using the above-mentioned tube furnace, comprising the following steps:

[0018] Loading and initialization: Open the observation window, place the precursor raw material into the raw material container of the raw material boat, and close the observation window; lower the raw material boat to the low-temperature waiting area (inside the raw material chamber) at the bottom of the furnace tube using the raw material boat lifting system; keep the insert-type baffle valve in the closed state.

[0019] Transport and Reaction: Open the insert-type baffle valve and place the substrate on the substrate trailer inside the furnace tube chamber, positioning the substrate in the upper half of the furnace tube chamber, which is the growth zone. This zone is an independent temperature zone, and its temperature is stable within the reaction temperature range. Carrier gas is introduced through the second airtight component, allowing it to flow into the various gas channels of the raw material boat. The raw material boat lifting system is activated to smoothly raise the raw material boat to the set high-temperature evaporation zone, which is located inside the furnace tube chamber and below the growth zone. The high-temperature evaporation zone is an independent temperature zone, and the carrier gas uniformly carries the precursor vapor upwards. The precursor vapor enters the growth zone and undergoes a deposition reaction on the substrate surface.

[0020] Termination and Isolation: After the preset reaction time is reached, the raw material boat lifting system is first controlled to quickly lower the raw material boat to the low-temperature waiting area to cool it down rapidly and stop evaporation. Then, the insert-type baffle valve is closed to physically cut off the airflow and material exchange between the furnace tube chamber and the raw material chamber. The growth zone completes the subsequent process under independent temperature control.

[0021] Material handling and preparation: After the growth zone has cooled, remove the substrate; open the observation window to replace or replenish the raw materials in preparation for the next round of reaction.

[0022] Beneficial Effects: Compared with the prior art, the present invention has the following significant advantages: The present invention provides a tubular furnace with an integrated raw material delivery and reaction isolation system. This tubular furnace, through the synergistic effect of multi-channel uniform carrier gas distribution, an airtight vertical lifting raw material boat, and a rapidly opening and closing insert-type baffle valve, achieves a uniform and stable supply of precursor vapor and precise "hard-switching" control of the reaction process; the tubular furnace of the present invention can significantly improve wafer-level deposition uniformity and process repeatability, and is suitable for large-area fabrication of two-dimensional and three-dimensional semiconductor materials. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a tube furnace with reaction isolation function according to an embodiment of the present invention. Figure 1 .

[0024] Figure 2 This is a schematic diagram of the structure of the furnace tube compartment and the first airtight component according to an embodiment of the present invention.

[0025] Figure 3 This is a schematic diagram of the structure of the raw material boat and the second airtight component in an embodiment of the present invention.

[0026] Figure 4 This is a schematic diagram of the raw material boat lifting system according to an embodiment of the present invention.

[0027] Figure 5 This is a schematic diagram of the tubular furnace in its reset state according to an embodiment of the present invention.

[0028] Figure 6This is a schematic diagram of the structure of the tubular furnace reaction state according to an embodiment of the present invention.

[0029] Figure 7 This is a schematic diagram of the structure of a tube furnace with reaction isolation function according to an embodiment of the present invention. Figure 2 .

[0030] Reference numerals: 100, Furnace tube compartment; 110, Hanging wire; 120, Substrate trolley; 200, Raw material compartment; 210, Raw material boat; 211, Raw material container; 212, Gas passage; 213, Perforated insulation column; 220, Observation window; 300, Raw material boat lifting system; 310, Threaded rod; 320, Electric motor; 330, Bellows; 340, Upper plate; 350, Lower plate; 360, Nut plate; 400, Heating electrocoupling wire assembly; 410, First heating element. Temperature zone; 420, Second heating temperature zone; 500, Baffle valve; 600, Air pressure pointer; 700, First airtight assembly; 710, First mixing chamber flange; 720, First air inlet pipe; 730, First air outlet pipe; 800, Second airtight assembly; 810, Second mixing chamber flange; 820, Second air inlet pipe; 830, Second air outlet pipe; 840, Pump connection pipe; 900, Frame; 10, Ladder; 11, Integrated control center; 12, Mechanical pump. Detailed Implementation

[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0032] Example 1

[0033] like Figure 1 As shown, this embodiment of the invention provides a tubular furnace with reaction isolation function, including a furnace tube compartment 100, a raw material compartment 200, a raw material boat lifting system 300, a heating electrocoupling wire assembly 400, a baffle valve 500, a pressure gauge 600, a first airtight component 700, and a second airtight component 800. The furnace tube compartment 100 and the raw material compartment 200 are connected to form the furnace tube of the tubular furnace. The upper end of the furnace tube compartment 100 is the upper end of the furnace tube, and the lower end of the raw material compartment 200 is the lower end of the furnace tube. The raw material boat lifting system 300 is connected to the raw material boat inside the raw material compartment 200 and is used to lift and lower the raw material boat, allowing it to move up and down within the furnace tube. The heating electrocoupling wire assembly 400 covers the outside of the furnace tube compartment 100, and the baffle valve 500 is located between the furnace tube compartment 100 and the raw material compartment 200, serving as both a connection and an isolation mechanism between the two compartments. The first airtight component 700 is installed at the upper end of the furnace tube for sealing and for supplying / exporting gas to / from the furnace tube. The second airtight component 800 is installed at the lower end of the furnace tube for sealing and for supplying / exporting gas to / from the furnace tube.

[0034] A heating coupler wire assembly 400 surrounds the furnace tube chamber 100. The heating coupler wire assembly 400 includes several parallel heating coupler wires, electrothermal couplers inserted into each heating coupler wire, and a heat insulation layer covering each heating coupler wire. The furnace tube chamber 100 is divided into several temperature zones. During the reaction, the substrate inside the furnace tube chamber 100 is located in one temperature zone, and the raw material boat 210 inside the furnace tube chamber 100 is located in another temperature zone. The temperatures of the two zones are different. The number of heating coupler wires depends on the number of temperature zones. Preferably, there are two temperature zones, i.e., two heating coupler wires.

[0035] The baffle valve 500 is an insertion type baffle valve used to connect or disconnect the furnace tube compartment 100 and the raw material compartment 200 according to the reaction progress of the tubular furnace. When no reaction occurs in the furnace tube, the baffle valve 500 is inserted, separating the furnace tube compartment 100 and the raw material compartment 200, with the substrate located inside the furnace tube compartment 100 and the raw material boat located inside the raw material compartment 200; when a reaction occurs in the furnace tube, the substrate is located inside the furnace tube compartment 100, the baffle valve 500 is pulled out, and the raw material boat lifting system 300 drives the raw material boat to rise, moving the raw material boat into the furnace tube compartment 100 and positioning it below the substrate.

[0036] like Figure 2 As shown, a suspension wire 110 is fixed to the top of the furnace tube compartment 100, and a substrate holder 120 is fixed to the suspension wire 110. The substrate holder 120 is used to place the substrate. A first airtight assembly 700 is installed at the top of the furnace tube compartment 100. The first airtight assembly 700 includes a first mixing chamber flange 710, a first inlet pipe 720, and a first outlet pipe 730. The first mixing chamber flange 710 is installed at the top of the furnace tube compartment 100. The first inlet pipe 720 and the first outlet pipe 730 are respectively connected to the first mixing chamber flange 710. The first inlet pipe 720 is used to connect to an external gas cylinder, and the first outlet pipe 730 is used to discharge the exhaust gas from the furnace tube.

[0037] like Figure 1 and 3 As shown, the raw material compartment 200 is equipped with an observation window 220 for changing raw materials. Inside the raw material compartment 200 is a raw material boat 210, which includes a raw material container 211, a gas channel 212, and a perforated heat-insulating column 213. The gas channel 212 passes through the bottom of the raw material container 211 and connects to it. The perforated heat-insulating column 213 surrounds the gas channel. The observation window 220 is used for changing the raw materials inside the raw material container 211.

[0038] The bottom of the raw material hopper 200 is provided with a second airtight assembly 800. The second airtight assembly 800 includes a second mixing chamber flange 810, a second inlet pipe 820, a second outlet pipe 830, and a pump connection pipe 840. The second mixing chamber flange 810 is installed at the bottom of the raw material hopper 200. The second inlet pipe 820, the second outlet pipe 830, and the pump connection pipe 840 are respectively connected to the second mixing chamber flange 810. The second inlet pipe 820 is used to connect to an external gas cylinder. The second outlet pipe 830 is used to discharge the exhaust gas from the furnace tube. The pump connection pipe 840 is used to connect to a gas pump.

[0039] like Figure 4 As shown, the raw material boat lifting system 300 includes a threaded rod 310, a motor 320, a bellows 330, an upper plate 340, a lower plate 350, a nut plate 360, and an infrared sensor limiter. The upper end of the threaded rod 310 is mounted on the upper plate 340, and the lower end is fixed to the lower plate 350 via the motor 320. The bottom of the bellows 330 is fixed to the raw material boat 210 and is mounted on the nut plate 360, which is sleeved on the threaded rod 310. The motor 320 is connected to the threaded rod 310 via a coupling and bearings. The infrared sensor limiter is connected to the motor 320. The compressible bellows 330 is used to maintain the airtightness of the system during lifting, and the airtight bellows design enables long-distance movement of the raw material boat. The raw material container 211 in the raw material boat 210 is installed above the corrugated pipe, and the perforated heat insulation column 213 and part of the gas channel 212 are installed inside the corrugated pipe.

[0040] When the raw material boat lifting system 300 is started, the drive screw 310 of the motor 320 rotates, causing the raw material boat 210 to rise or fall. When the raw material boat 210 rises, the bellows 330 is compressed, and the raw material boat 210 can be moved from the raw material bin 200 to the furnace tube bin 100.

[0041] Example 2

[0042] like Figure 4-5As shown, this embodiment of the invention provides a tubular furnace with reaction isolation function, including a furnace tube compartment 100, a raw material compartment 200, a raw material boat lifting system 300, a heating electrocoupling wire assembly 400, a baffle valve 500, a pressure gauge 600, a first airtight component 700, a second airtight component 800, and a frame 900. The furnace tube compartment 100 and the raw material compartment 200 are connected to form the furnace tube of the tubular furnace. The upper end of the furnace tube compartment 100 is the upper end of the furnace tube, and the lower end of the raw material compartment 200 is the lower end of the furnace tube. The raw material boat lifting system 300 is connected to the raw material boat inside the raw material compartment 200 and is used to lift and lower the raw material boat, allowing it to move up and down within the furnace tube. The heating electrocoupling wire assembly 400 covers the outside of the furnace tube compartment 100. The baffle valve 500 is located between the furnace tube compartment 100 and the raw material compartment 200, and is used for both communication and isolation between the furnace tube compartment 100 and the raw material compartment 200. The first airtight assembly 700 is installed at the upper end of the furnace tube for sealing and for allowing / exiting gas into / out of the furnace tube. The second airtight assembly 800 is installed at the lower end of the furnace tube for sealing and for allowing / exiting gas into / out of the furnace tube. The frame 900 is used to fix the furnace tube of the tubular furnace.

[0043] This embodiment provides a method for preparing materials using the above-mentioned tubular furnace, including the following steps:

[0044] Loading and Initialization: Open the observation window 220, place the precursor raw material into the raw material container 211 of the raw material boat 210, and close the observation window 220; lower the raw material boat 210 to the low-temperature waiting area (inside the raw material chamber 200) at the bottom of the furnace tube using the raw material boat lifting system 300; keep the insert-type baffle valve 500 in the closed state, and the status of each component is as follows. Figure 4 As shown.

[0045] Transport and Reaction: Open the insertion baffle valve 500 and place the substrate on the substrate trailer 120 inside the furnace tube chamber 100, positioning the substrate in the upper half of the furnace tube chamber 100. This part is the growth zone, an independent temperature zone where the temperature is stable within the reaction temperature range. Carrier gas is introduced through the second airtight component 800, diverting it into the gas channels 212 of the raw material boat 210. The raw material boat lifting system 300 is activated, smoothly raising the raw material boat 210 to the designated high-temperature evaporation zone, located inside the furnace tube chamber 100 and below the growth zone. The high-temperature evaporation zone is an independent temperature zone, where the carrier gas uniformly carries the precursor vapor upwards. The precursor vapor enters the growth zone and undergoes a deposition reaction on the substrate surface. The state of each component is as follows: Figure 5 As shown.

[0046] Termination and Isolation: After the preset reaction time is reached, the raw material boat lifting system 300 is first controlled to rapidly lower the raw material boat 210 to the low-temperature waiting area, allowing it to cool quickly and stop evaporation. Then, the insertion-type baffle valve 500 is closed to physically cut off the airflow and material exchange between the furnace tube chamber 100 and the raw material chamber 200. The growth zone completes the subsequent process under independent temperature control, and the status of each component is as follows: Figure 4.

[0047] Material handling and preparation: After the growth zone has cooled, remove the substrate; open the observation window 220 to replace or replenish the raw materials in preparation for the next round of reaction.

[0048] Example 3

[0049] like Figure 1-6 As shown, this embodiment of the invention provides a tubular furnace with reaction isolation function, including a furnace tube compartment 100, a raw material compartment 200, a raw material boat lifting system 300, a heating electrocoupling wire assembly 400, a baffle valve 500, a pressure gauge 600, a first airtight component 700, a second airtight component 800, a frame 900, a ladder 10, an integrated control center 11, and a mechanical pump 12. The furnace tube compartment 100 and the raw material compartment 200 are connected to form the furnace tube of the tubular furnace, with the upper end of the furnace tube compartment 100 being the upper end of the furnace tube and the lower end of the raw material compartment 200 being the lower end of the furnace tube. The raw material boat lifting system 300 is connected to the raw material boat inside the raw material compartment 200 and is used to lift and lower the raw material boat, allowing it to move up and down within the furnace tube. The heating electrocoupling wire assembly 400 covers the outside of the furnace tube compartment 100, and the baffle valve 500 is located between the furnace tube compartment 100 and the raw material compartment 200, serving as both a connection and an isolation mechanism between the two compartments. The first airtight assembly 700 is installed at the upper end of the furnace tube for sealing and for allowing / exiting gas into / out of the furnace tube. The second airtight assembly 800 is installed at the lower end of the furnace tube for sealing and allowing / exiting gas into / out of the furnace tube. The frame 900 is used to fix the tubular furnace tube. A ladder is set on one side of the frame 900 for operators to load and unload substrates or raw materials. The mechanical pump 12 is connected to the second airtight assembly 800 to provide airflow power.

[0050] The raw material boat 210 includes a raw material container 211 for holding solid or liquid precursors. The raw material container 211 has at least two independent longitudinal gas channels 212 inside. The gas channels 212 are distributed around the bottom of the raw material container 211, so that the carrier gas can be diverted and flow evenly over the surface of the raw material, carrying the evaporated precursor vapor.

[0051] The raw material boat lifting system 300 is used to drive the raw material boat 210 to make vertical precision lifting and lowering movements inside the furnace tube; it includes a threaded rod 310, a motor 320, a bellows 330, an upper plate 340, a lower plate 350, a nut plate 360, and an infrared sensor limiter. The bellows 330 is a high-temperature resistant and airtight bellows. One end of the bellows is connected to the flange at the lower port of the furnace tube (lower port of the raw material compartment 200), and the other end is connected to the nut plate 360, forming a retractable dynamic sealing structure to ensure the overall airtightness of the furnace tube system during the lifting and lowering of the raw material boat 210.

[0052] An insert-type baffle valve 500 is horizontally installed inside the furnace tube, located between the furnace tube compartment 100 and the raw material compartment 200. The baffle valve has a valve plate and a drive mechanism, which can switch between the "open" and "closed" states. When closed, its valve plate can completely isolate the furnace tube compartment 100 and the raw material compartment 200.

[0053] The integrated control center 11 is electrically connected to the electric motor 320 of the raw material boat lifting system, the drive mechanism of the insertion-type baffle valve 500, the heating electric coupler group 400 of the tubular furnace, and the gas system, for coordinated control of the position of the raw material boat, the opening and closing of the baffle valve, and the process sequence. The gas system includes a mechanical pump 12, gas cylinders, and flow meters, etc.

[0054] The transmission mechanism of the raw material boat lifting system 300 is a screw and nut mechanism, and it is equipped with an infrared or photoelectric sensor limiter to achieve closed-loop precise control of the lifting position of the raw material boat.

[0055] The high-temperature resistant airtight corrugated pipe is made of multi-layer stainless steel or high-temperature alloy corrugated pipe, and its stroke is greater than the total distance that the raw material boat needs to move.

[0056] The insert-type baffle valve is a gate valve or a butterfly valve, and the valve plate and valve seat are made of high-temperature resistant and corrosion-resistant materials, such as molybdenum, tungsten, or stainless steel with a ceramic coating.

[0057] On the side wall of the furnace tube below the insert-type baffle valve, there is a sealable and openable observation window 220 for replacing or replenishing the precursor in the raw material boat after the system has cooled down, without having to disassemble the entire lower end of the furnace tube.

[0058] Example 4

[0059] like Figure 1-7As shown, this embodiment of the invention provides a tubular furnace with reaction isolation function, including a furnace tube compartment 100, a raw material compartment 200, a raw material boat lifting system 300, a heating electrocoupling wire assembly 400, a baffle valve 500, a pressure gauge 600, a first airtight component 700, a second airtight component 800, a frame 900, a ladder 10, an integrated control center 11, and a mechanical pump 12. The furnace tube compartment 100 and the raw material compartment 200 are connected to form the furnace tube of the tubular furnace, with the upper end of the furnace tube compartment 100 being the upper end of the furnace tube and the lower end of the raw material compartment 200 being the lower end of the furnace tube. The raw material boat lifting system 300 is connected to the raw material boat inside the raw material compartment 200 and is used to lift and lower the raw material boat, allowing it to move up and down within the furnace tube. The heating electrocoupling wire assembly 400 covers the outside of the furnace tube compartment 100, and the baffle valve 500 is located between the furnace tube compartment 100 and the raw material compartment 200, serving as both a connection and an isolation mechanism between the two compartments. The first airtight assembly 700 is installed at the upper end of the furnace tube for sealing and for allowing / exiting gas into / out of the furnace tube. The second airtight assembly 800 is installed at the lower end of the furnace tube for sealing and allowing / exiting gas into / out of the furnace tube. The frame 900 is used to fix the tubular furnace tube. A ladder is set on one side of the frame 900 for operators to load and unload substrates or raw materials. The mechanical pump 12 is connected to the second airtight assembly 800 to provide airflow power.

[0060] The raw material boat 210 includes a raw material container 211 for holding solid or liquid precursors, with gas channels 212 distributed around the bottom of the raw material container 211. The raw material container 211 is made of high-purity alumina ceramic, and has six independent fan-shaped gas channels 212 evenly distributed around its circumference. The central raw material container 211 is a crucible-type raw material tray. The carrier gas is distributed to each gas channel 212 through the inlet pipe of the second airtight component 800 at the bottom.

[0061] The raw material boat lifting system 300 includes a threaded rod 310, a motor 320, a bellows 330, an upper plate 340, a lower plate 350, a nut plate 360, and an infrared sensor limiter. The motor 320 of the raw material boat lifting system 300 is connected to the threaded rod 310 via a coupling. The bellows 330 is made of 316L stainless steel, and its upper and lower flanges are connected to the lower flange of the raw material hopper 200 and the nut plate 360, respectively.

[0062] The insertion-type baffle valve 500 is horizontally welded to the inner wall of the furnace tube, located approximately 20 cm above the raw material boat. It is a pneumatic gate valve, with the valve plate composed of two polished molybdenum plates joined together. Driven by an external cylinder via a valve stem, it can open and close within 2 seconds. An observation window 220 with a water-cooled flange and a sight glass is located on the side wall of the furnace tube below the baffle valve.

[0063] The integrated control center 11 uses a PLC to program and control the lifting speed and position of the raw material boat, the opening and closing sequence of the baffle valve, and is linked with furnace temperature and flow parameters.

[0064] Example 5

[0065] The tube furnaces in Examples 1-4 are suitable for the preparation of various thin films, especially for the growth of all materials that require elemental vapor precursors. This example only uses molybdenum disulfide (MoS2) thin film as an example for detailed description.

[0066] This embodiment provides a method for preparing molybdenum disulfide (MoS2) thin films, including the following steps:

[0067] After the previous growth cycle is completed in the tubular furnace, the high-purity sulfur powder is placed in the raw material container 211 of the raw material boat 210.

[0068] A silicon substrate with a molybdenum oxide seed layer on its surface is placed inside a substrate tray 120, and the furnace body is sealed.

[0069] Start the raw material boat lifting system 300 to reset the raw material boat to the raw material compartment 200. At this time, the raw material compartment 200 will have residual heat from the raw material boat, which is recorded as a low temperature zone. Close the baffle valve.

[0070] Argon gas is introduced into the furnace tube chamber 100 through the first airtight component 700. The furnace tube chamber 100 is divided into two temperature zones: a growth zone and a high temperature zone. The growth zone is heated to 750°C and stabilized.

[0071] Argon gas is introduced into the raw material boat 210 as a carrier gas and then diverted into six gas channels 212.

[0072] Open the baffle valve and lift the raw material boat 210 to the upper high-temperature zone (about 500°C) at a speed of 10 mm / s, and the sulfur powder will evaporate rapidly.

[0073] Sulfur vapor is carried to the growth region by the carrier gas and reacts with molybdenum oxide on the substrate surface to form a MoS2 thin film, which is grown for 15 minutes.

[0074] The growth end command is issued: First, the raw material boat 210 is rapidly lowered to the low-temperature zone. Then, the baffle valve (5) is immediately closed pneumatically (time < 2 seconds). The growth zone is then cooled to room temperature under an argon atmosphere, and the sample is removed. The loading and unloading window (6) is opened to replenish sulfur powder in preparation for the next growth.

[0075] This system enables uniform supply of sulfur vapor and instantaneous termination of the reaction, resulting in a 2-inch MoS2 film thickness uniformity (intra-sheet non-uniformity) better than ±3%.

Claims

1. A tube furnace characterized by, The furnace tube cabin, the raw material cabin, and the raw material boat lifting system are provided.

2. The tube furnace according to claim 1, characterized in that The raw material cabin is externally provided with an observation window for replacing raw materials.

3. The tube furnace according to claim 1, characterized in that The raw material boat comprises a raw material holding dish, a gas passage, and a perforated heat insulation column.

4. The tube furnace according to claim 1, characterized in that The transmission mechanism of the raw material boat lifting system is a lead screw nut mechanism, and an infrared or photoelectric sensing limiter is provided.

5. The tube furnace according to claim 1 or 4, characterized in that The raw material boat lifting system comprises a threaded rod, a motor, a bellows, an upper plate, a lower plate, and a nut plate.

6. The tube furnace according to claim 1, characterized in that The furnace tube cabin is divided into several temperature zones.

7. The tube furnace according to claim 1, characterized in that A baffle valve is provided between the furnace tube cabin and the raw material cabin for communication and isolation.

8. The tube furnace according to claim 1, characterized in that The furnace tube cabin is provided with a lifting wire, the top of which is fixed to the top of the furnace tube cabin, and the bottom of which is fixed with a substrate drag.

9. The tube furnace according to claim 1, characterized in that The top of the furnace tube cabin is provided with a first airtight assembly, which comprises a first mixed gas cavity flange sealingly connected to the top of the furnace tube cabin, a first gas inlet pipe and a first gas outlet pipe connected to the first mixed gas cavity flange, respectively.

10. The tube furnace according to claim 1, characterized in that The bottom of the raw material cabin is provided with a second airtight assembly, which comprises a second mixed gas cavity flange sealingly connected to the bottom of the raw material cabin, a second gas inlet pipe, a second gas outlet pipe, and a pump connecting pipe connected to the second mixed gas cavity flange, respectively.

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