Carbon-doping device for gallium arsenide single crystal growth

Abstract

This invention discloses a carbon-doped device for gallium arsenide single crystal growth, applied in the field of single crystal growth. Utilizing the design of the insertion cavity and exhaust channel, particulate matter from the reaction interface is actively guided into the collection hood under the action of airflow and gravity, preventing stagnation and ensuring sufficient contact between the graphite column and the support disk interface. When the reactive gas enters the suddenly increased volume of the collection hood from the narrow insertion cavity, the flow rate drops sharply, thereby accelerating the sedimentation of particulate matter. Furthermore, the large surface area of ​​the inner wall of the collection hood can react and consume graphite particles and melt and adhere quartz particles, achieving wall-side trapping. Through the step-by-step action of the above steps, the particulate matter content in the gas entering the crystal growth zone is significantly reduced, improving crystal purity. In addition, the removal effect of stripped particles is further improved by using guide cylinders one and two, in conjunction with a porous quartz filter ring located inside the exhaust port.

Description

Technical Field

[0001] This invention relates to the field of single crystal growth, and particularly to a carbon-doped apparatus for gallium arsenide single crystal growth. Background Technology

[0002] In the field of gallium arsenide single crystal preparation, semi-insulating gallium arsenide single crystals have attracted much attention due to their key applications in microwave and millimeter-wave devices. The core of achieving semi-insulating properties lies in the precise control of carbon doping. Traditional carbon doping processes mostly use solid carbon sources for direct doping, but there are problems such as uneven carbon concentration distribution, large axial gradient, and poor process stability, resulting in low single crystal yield and difficulty in ensuring the consistency of electrical performance. In addition, solid carbon sources are prone to volatilization or incomplete decomposition at high temperatures, which further exacerbates the difficulty of controlling doping uniformity.

[0003] The existing patent with publication number CN113136616B discloses a carbon doping device and method for growing semi-insulating gallium arsenide single crystals. By assembling a PBN crucible inside a quartz tube, installing sealing clips at both ends, and setting up gas filling pipelines (including parallel gas filling and carbon filling pipelines) and exhaust pipelines (including parallel gas venting and vacuuming pipelines), and configuring corresponding valves to control the on and off of each pipeline, the oxygen baking process and the C deposition process can be carried out sequentially on the same equipment, achieving the effect of simplifying equipment and saving heat energy loss.

[0004] A patent application with publication number CN101603208A discloses a method for carbon doping gallium arsenide using a quartz tube for growing semi-insulating gallium arsenide. The method involves synthesizing GaAs polycrystalline materials from Ga and As polycrystalline materials to form GaAs polycrystalline materials, placing the GaAs polycrystalline materials, seed crystals, and boron oxide in a PBN crucible, and then loading it into a quartz tube. Pure graphite is then fixed in the quartz tube and sealed under vacuum welding. The quartz tube is then placed in a VGF single crystal furnace for atmosphere doping and single crystal growth. Finally, the PBN crucible is immersed in methanol, allowing high-purity raw materials to complete crystal growth and carbon doping under precise temperature control, thus achieving efficient preparation of semi-insulating GaAs single crystals.

[0005] The aforementioned prior art discloses a technical solution for carbon doping by depositing carbon on the inner wall of a PBN crucible using a carbon deposition process. It also discloses a technical solution for atmospheric carbon doping by placing a graphite column inside a quartz cap to react and generate carbon monoxide. However, the prior art still has shortcomings. When carbon doping is achieved by reacting a graphite column with a quartz cap to generate carbon monoxide, the consumption of raw materials causes the reaction interface between the two to become loose and pulverized. Under the disturbance of the reaction gas, a large number of particles are generated. These particles enter the crystal growth zone and react with liquid sealants, etc., which destroy the thermal field and gas field, introduce impurities, and reduce the crystal quality. Summary of the Invention

[0006] The core of this invention lies in collecting and eliminating stripped particles through a support plate and a collection hood, solving the problem in the prior art that stripped particles easily enter the crystal growth area with the airflow and affect the crystal quality; at the same time, the adsorption and elimination effect of the collection hood on stripped particles is improved through guide cylinder one and guide cylinder two.

[0007] To solve the above problems, the present invention adopts the following technical solution.

[0008] A carbon-doped apparatus for gallium arsenide single crystal growth includes a single crystal furnace, a quartz tube, and a graphite column. The quartz tube includes a tube body and a quartz cap welded and fixed to the upper end of the tube body. The inner end of the quartz cap is provided with a gas generating mechanism for generating carbon monoxide gas.

[0009] The gas generating mechanism includes a mounting cylinder threaded to the inner wall of a quartz cap, a bearing plate threaded to the lower end of the mounting cylinder, a collecting hood fixedly connected to the lower end of the bearing plate, an insertion cavity for inserting graphite pillars on the bearing plate, the insertion cavity being an inverted conical cavity wider at the top and narrower at the bottom, the lower end of the insertion cavity communicating with the inner cavity of the collecting hood, and multiple circumferentially evenly distributed exhaust channels on the inner wall of the insertion cavity; an insertion cylinder fixedly connected to the upper end of the bearing plate, the upper end of the insertion cylinder being inserted into the inner wall of the mounting cylinder, the bearing plate, the mounting cylinder, and the insertion cylinder together forming an annular cavity, multiple circumferentially evenly distributed upward flow channels on the bearing plate, the upward flow channels being used to connect the annular cavity and the inner cavity of the collecting hood, and an exhaust hole connecting the annular cavity and the inner cavity of the quartz cap on the outer wall of the mounting cylinder.

[0010] Furthermore, the mounting cylinder is a hollow cylindrical structure with an open bottom. A threaded post integrally formed with it is fixedly connected to the center of the upper end of the mounting cylinder. A threaded cylinder integrally formed with it is fixedly connected to the center of the inner wall of the quartz cap. The threaded post and the threaded cylinder are threadedly matched. The bearing plate has a disc-shaped structure. The bearing plate has a threaded groove on the outside of the upper flow channel. The lower end of the mounting cylinder has a threaded protrusion that matches the threaded groove. The insertion cylinder is a hollow cylindrical structure with open top and bottom ends. The top wall of the mounting cylinder has an insertion groove for the upper end of the insertion cylinder to be inserted.

[0011] Furthermore, the graphite column includes an upper cylindrical portion, a frustum portion fixedly connected to the lower end of the upper cylindrical portion, a lower cylindrical portion fixedly connected to the lower end of the frustum portion, the lower part of the upper cylindrical portion and the conical sidewall of the frustum portion both contact the inner wall of the insertion cavity, and the lower cylindrical portion extends into the collection hood.

[0012] Furthermore, the diameter of the lower cylindrical part is smaller than the diameter of the lower opening of the insertion cavity, and an annular gap is formed between the outer wall of the lower cylindrical part and the inner wall of the lower opening of the insertion cavity to allow the reaction gas and stripping particles to pass through, and the exhaust channel is connected to the annular gap.

[0013] Furthermore, multiple vertically distributed flow-blocking rings are fixedly connected to the inner wall of the mounting cylinder. The flow-blocking rings are annular structures with their inner ends facing downwards, and they are set inside the annular cavity.

[0014] Furthermore, the lower end face of the bearing plate is fixedly connected with two concentrically arranged guide cylinders. Guide cylinder one is connected to the insertion cavity and is flared, while guide cylinder two is cylindrical. The diameter of guide cylinder two is smaller than the diameter of the lower end of the guide cylinder. The lower opening of the upper flow channel is located between guide cylinder one and guide cylinder two.

[0015] Furthermore, the collection cover has a hollow hemispherical structure, with a thickening block fixedly connected to the center of its bottom, and a conical cavity opened at the upper end of the thickening block.

[0016] Furthermore, the outer wall of the plug-in cylinder is fitted with multiple trays located on the same horizontal plane, and the upper end of the trays abuts against a porous quartz filter ring disposed in the annular cavity. The installation height of the porous quartz filter ring is lower than the opening height of the exhaust port.

[0017] Compared with the prior art, the advantages of this invention are:

[0018] (1) The present invention utilizes the design of the insertion cavity and the exhaust channel to actively guide the particulate matter at the reaction interface into the collection hood under the action of airflow and gravity, so as to avoid its retention and ensure sufficient contact between the graphite column and the bearing disk interface. When the reaction gas enters the collection hood cavity with a sudden increase in volume from the narrow insertion cavity, the flow rate drops sharply, thereby accelerating the sedimentation of the particulate matter. In addition, the large surface area of ​​the inner wall of the collection hood can react and consume the graphite particles and melt and adhere the quartz particles, thus achieving wall capture. The annular cavity located between the insertion cylinder and the mounting cylinder constitutes a secondary barrier to prevent the settled particles from floating up with the airflow. Through the step-by-step action of the above links, the particulate matter content in the gas entering the crystal growth zone is significantly reduced, and the crystal purity is improved.

[0019] (2) The present invention uses guide cylinder one and guide cylinder two to allow the reaction gas carrying the stripping particles to flow into the cavity between guide cylinder two and collection hood after passing through guide cylinder one, thereby preventing the stripping particles from directly entering the upstream channel after entering the collection hood, improving the settling effect of the stripping particles and reducing the probability of dust. In addition, the porous quartz filter ring set inside the exhaust hole further improves the removal effect of the stripping particles. Attached Figure Description

[0020] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0021] Figure 2 This is a schematic diagram of the internal structure of the present invention;

[0022] Figure 3 This is a schematic diagram of the installation structure of the gas generating mechanism in this invention;

[0023] Figure 4 This is a three-dimensional structural diagram of the bearing disk and graphite column in this invention;

[0024] Figure 5 This is a cross-sectional assembly structure diagram of the bearing disk and graphite column in this invention;

[0025] Figure 6 This is a three-dimensional structural diagram of the gas generating mechanism in this invention;

[0026] Figure 7 This is a schematic diagram of the explosive assembly structure of the gas generating mechanism in this invention;

[0027] Figure 8 This is a cross-sectional assembly diagram of the support plate and the collection cover in this invention;

[0028] Figure 9 This is a schematic diagram showing the movement of the reactive gas and stripping particles within the gas generating mechanism in this invention.

[0029] Explanation of the labels in the diagram:

[0030] 1. Single crystal furnace; 2. Heating device; 3. Quartz tube; 301. Tube body; 302. Quartz cap; 303. Threaded cylinder; 4. Gas generating mechanism; 5. Support plate; 501. Insertion cavity; 502. Exhaust channel; 503. Upstream channel; 504. Threaded groove; 6. Mounting cylinder; 601. Threaded column; 602. Exhaust hole; 603. Annular cavity; 604. Flow-blocking ring; 605. Insertion groove; 7. Graphite column; 701. Upper cylindrical part; 702. Frustum-shaped part; 703. Lower cylindrical part; 8. Collection cover; 9. Insertion cylinder; 901. Support plate; 10. Porous quartz filter ring; 11. Guide cylinder one; 12. Guide cylinder two; 13. Thickening block; 14. PBN crucible; 15. Quartz seat. Detailed Implementation

[0031] The technical solutions will now be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention.

[0032] First implementation method

[0033] Please see Figures 1-9In one embodiment of the present invention, a carbon-doped apparatus for gallium arsenide single crystal growth includes a single crystal furnace 1, a quartz tube 3, and a graphite column 7. The quartz tube 3 includes a tube body 301 and a quartz cap 302 welded and fixed to the upper end of the tube body 301. The inner end of the quartz cap 302 is provided with a gas generating mechanism 4 for generating carbon monoxide gas. The gas generating mechanism 4 includes a mounting cylinder 6 threadedly connected to the inner wall of the quartz cap 302. The lower end of the mounting cylinder 6 is threadedly connected to a bearing plate 5. The lower end of the bearing plate 5 is fixedly connected to a collecting cover 8. The bearing plate 5 has an insertion cavity 501 for inserting the graphite column 7. The insertion cavity 501 is wider at the top and narrower at the bottom. The inverted conical cavity 501 has its lower end connected to the inner cavity of the collection cover 8. Multiple circumferentially distributed exhaust channels 502 are provided on the inner wall of the insertion cavity 501. An insertion tube 9 is fixedly connected to the upper end of the bearing plate 5. The upper end of the insertion tube 9 is inserted into the inner wall of the mounting tube 6. The bearing plate 5, the mounting tube 6 and the insertion tube 9 together form an annular cavity 603. Multiple circumferentially distributed upward channels 503 are provided on the bearing plate 5. The upward channels 503 are used to connect the annular cavity 603 and the inner cavity of the collection cover 8. An exhaust hole 602 is provided on the outer wall of the mounting tube 6 to connect the annular cavity 603 and the inner cavity of the quartz cap 302.

[0034] Specifically, during crystal growth, the area containing the graphite pillar 7 is heated. A carbon monoxide generation reaction occurs at the contact surface between the graphite pillar 7 and the support disk 5 (SiO2 + C → SiO + CO, where SiO2 originates from the quartz material of the support disk 5, and both SiO and CO are gases). As the reaction proceeds, graphite particles on the surface of the graphite pillar 7 and quartz particles at the contact surface between the support disk 5 and the graphite pillar 7 detach (the contact surface between the graphite pillar 7 and the support disk 5 is etched due to material consumption, and the surface structure gradually loosens and becomes pulverized). The reaction gas carries the detached carbon monoxide... The particles (graphite particles and quartz particles) enter the collection hood 8 through the exhaust channel 502 and the insertion cavity 501. Then, the reaction gas enters the annular cavity 603 through the upward channel 503. Finally, the reaction gas is discharged from the exhaust hole 602 into the inner cavity of the quartz cap 302. The carbon monoxide gas in the reaction gas gradually fills downward. After passing through the liquid sealant (molten boron oxide fluid), the carbon monoxide gas comes into contact with the molten gallium arsenide and decomposes into carbon atoms. The carbon atoms enter the gallium arsenide lattice as acceptor impurities, compensate for the intrinsic shallow donors, and achieve semi-insulating characteristics.

[0035] Compared to traditional gallium arsenide carbon doping devices, this invention, through the insertion cavity 501 and the exhaust channel 502, allows graphite and quartz particles to enter the collection hood 8 under the combined action of airflow and their own gravity, achieving downward settling of the graphite and quartz particles. This prevents them from remaining at the reaction interface between the graphite column 7 and the support disk 5, ensuring full contact between the reaction interface. Simultaneously, the reactant gas enters the suddenly expanding volume from the gradually narrowing insertion cavity 501. The inner cavity of the collecting hood 8 reduces the flow rate, accelerating the settling of graphite and quartz particles. Furthermore, the collecting hood 8 has an inner wall with a large surface area, which reacts and consumes the graphite particles and melts and adheres the quartz particles, further reducing the amount of graphite and quartz particles carried in the reaction gas. Additionally, the annular cavity 603 located between the insertion cylinder 9 and the mounting cylinder 6 further prevents the stripping particles from floating upwards with the airflow, reducing the content of stripping particles in the reaction gas, thereby reducing the probability of stripping particles entering the crystal growth region and improving the purity of crystal growth.

[0036] Please see Figure 2 The single crystal furnace 1 is equipped with a heating device 2, which includes multiple vertically distributed annular heating coils. A quartz seat 15 is provided inside the heating device 2, and a quartz tube 3 is inserted into the quartz seat 15. The quartz seat 15 is fixedly connected to the bottom wall of the single crystal furnace 1, and a PBN crucible 14 is inserted into the lower part of the tube body 301.

[0037] Specifically, during gallium arsenide crystal growth, a seed crystal, gallium arsenide polycrystalline raw material, and liquid sealant (boron oxide) are added into the PBN crucible 14. A gas generating mechanism 4 is installed inside a quartz cap 302. The quartz cap 302 area and the PBN crucible 14 area are heated separately by a heating device 2, so that the carbon monoxide gas generated by the gas generating mechanism 4 enters the crystal growth area where the PBN crucible 14 is located. It should be noted that the single crystal furnace 1 is a VCF single crystal furnace, which is existing technology and will not be described in detail in this application.

[0038] Please see Figure 3 and Figure 6 The mounting cylinder 6 is a hollow cylindrical structure with an open bottom. A threaded post 601 integrally formed with it is fixedly connected to the center of the upper end of the mounting cylinder 6. A threaded cylinder 303 integrally formed with it is fixedly connected to the center of the inner wall of the quartz cap 302. The threaded post 601 and the threaded cylinder 303 are threadedly matched.

[0039] Specifically, the threaded column 601 and threaded cylinder 303 facilitate the installation and disassembly of the gas generating mechanism 4.

[0040] Please see Figure 3 and Figure 4The bearing plate 5 has a disc-shaped structure. The bearing plate 5 is located on the outside of the upper flow channel 503 and has a threaded groove 504. The lower end of the mounting cylinder 6 has a threaded protrusion that mates with the threaded groove 504. The plug-in cylinder 9 is a hollow cylindrical structure with openings at both the top and bottom. The top wall of the mounting cylinder 6 has a plug-in groove 605 for the upper end of the plug-in cylinder 9 to be inserted.

[0041] Specifically, when installing the graphite column 7, the upper part of the mounting cylinder 6 is screwed off to remove the mounting cylinder 6 from the quartz cap 302. Then, the mounting cylinder 6 is held and the bearing plate 5 is screwed off to remove the mounting cylinder 6 from the bearing plate 5. The graphite column 7 is then inserted into the insertion cavity 501. Finally, the mounting cylinder 6 and the bearing plate 5 are assembled, and the threaded column 601 of the mounting cylinder 6 is screwed into the threaded cylinder 303 of the quartz cap 302 to complete the loading operation of the graphite column 7. In addition, the cavity where the graphite column 7 is located is separated from the annular cavity 603 by the insertion cylinder 9, so that the generated reaction gas first enters the collection hood 8, thereby collecting the stripped particles (graphite particles and quartz particles). Then, under the action of gas pressure, the reaction gas enters the annular cavity 603 from the collection hood 8 through the upper flow channel 503, and finally exits into the quartz cap 302 from the exhaust port 602.

[0042] Please see Figure 3 , Figure 4 and Figure 5 The graphite column 7 includes an upper cylindrical part 701, a frustum part 702 fixedly connected to the lower end of the upper cylindrical part 701, and a lower cylindrical part 703 fixedly connected to the lower end of the frustum part 702. The lower part of the upper cylindrical part 701 and the conical sidewall of the frustum part 702 are in contact with the inner wall of the insertion cavity 501, and the lower cylindrical part 703 extends into the collection cover 8.

[0043] Specifically, by including the upper cylindrical portion 701, the frustum portion 702, and the lower cylindrical portion 703, the center of gravity of the graphite column 7 is shifted downward, which improves the insertion stability of the graphite column 7 in the insertion cavity 501, thereby improving the stability of the contact interface between the graphite column 7 and the insertion cavity 501, thus improving the stability of the solid-solid reaction and keeping the carbon monoxide generation rate stable.

[0044] Please see Figure 4 and Figure 5 The diameter of the lower cylindrical portion 703 is smaller than the diameter of the lower opening of the insertion cavity 501. An annular gap is formed between the outer wall of the lower cylindrical portion 703 and the inner wall of the lower opening of the insertion cavity 501 to allow the reaction gas and stripping particles to pass through. The exhaust channel 502 is connected to the annular gap.

[0045] Specifically, by providing an exhaust channel 502, the airflow at the reaction interface between the graphite column 7 and the carrier disk 5 is discharged more smoothly, reducing the vibration of the graphite column 7 caused by the airflow. In addition, it has a better collection effect on the stripped particles.

[0046] Please see Figure 3 Multiple vertically distributed flow-blocking rings 604 are fixedly connected to the inner wall of the mounting cylinder 6. The flow-blocking rings 604 are annular structures with their inner ends facing downwards, and are located inside the annular cavity 603.

[0047] Specifically, the flow-blocking ring 604 set in the annular cavity 603 further blocks the stripping particles that float up with the reaction gas flow, thereby further reducing the amount of stripping particles entering the inner cavity of the quartz cap 302.

[0048] Second implementation method

[0049] Based on the first implementation, please refer to Figure 3 , Figure 7 , Figure 8 and Figure 9 The lower end face of the bearing plate 5 is fixedly connected to a concentrically arranged guide cylinder 11 and guide cylinder 2 12. The guide cylinder 11 is connected to the insertion cavity 501 and is horn-shaped. The guide cylinder 2 12 is cylindrical. The diameter of the guide cylinder 2 12 is smaller than the diameter of the lower end of the guide cylinder 11. The lower end opening of the upper flow channel 503 is located between the guide cylinder 11 and the guide cylinder 2 12.

[0050] Specifically, by providing a guide cylinder 11, the reactive gas carrying the stripping particles flows into the cavity between the guide cylinder 2 12 and the collection hood 8 after passing through the guide cylinder 11. This prevents the stripping particles from directly entering the upstream channel 503 after entering the collection hood 8, thereby improving the settling effect of the stripping particles and reducing the probability of dust generation.

[0051] Please see Figure 3 and Figure 8 The collection cover 8 has a hollow hemispherical structure, and a thickening block 13 is fixedly connected to the center of its bottom. A conical cavity is opened at the upper end of the thickening block 13.

[0052] Specifically, by increasing the thickness of the center of the bottom of the collection hood 8 by thickening block 13, the graphite particles are prevented from reacting with the quartz inner wall at the center of the bottom of the collection hood 8, which would cause perforation at the bottom of the collection hood 8. In addition, by using the thickening block 13 with a conical cavity, the stripped particles carried by the reaction gas are fully spread in the bottom space of the collection hood 8, which facilitates the reaction of each graphite particle with the quartz inner wall of the collection hood 8.

[0053] Please see Figure 3 and Figure 7 Multiple support plates 901 located on the same horizontal plane are snapped onto the outer wall of the plug-in cylinder 9. The upper end of the support plate 901 abuts against a porous quartz filter ring 10 disposed in the annular cavity 603. The installation height of the porous quartz filter ring 10 is lower than the opening height of the exhaust port 602.

[0054] Specifically, the porous quartz filter ring 10 filters the exhaust reaction gas, further reducing the probability of graphite particles and quartz particles entering the quartz cap 302. It should be noted that the porous quartz filter ring 10 is a porous filter material made of sintered quartz powder, which has a specific pore size and high temperature stability, and is used to intercept graphite particles and quartz particles.

[0055] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A carbon-doped apparatus for gallium arsenide single crystal growth, characterized in that, It includes a single crystal furnace (1), a quartz tube (3) and a graphite column (7). The quartz tube (3) includes a tube body (301) and a quartz cap (302) welded and fixed to the upper end of the tube body (301). The inner end of the quartz cap (302) is provided with a gas generating mechanism (4) for generating carbon monoxide gas. The gas generating mechanism (4) includes a mounting cylinder (6) threadedly connected to the inner wall of a quartz cap (302). A bearing plate (5) is threadedly connected to the lower end of the mounting cylinder (6). A collection hood (8) is fixedly connected to the lower end of the bearing plate (5). An insertion cavity (501) for inserting a graphite column (7) is provided on the bearing plate (5). The insertion cavity (501) is an inverted conical cavity that is wider at the top and narrower at the bottom. The lower end of the insertion cavity (501) communicates with the inner cavity of the collection hood (8). Multiple circumferentially distributed exhaust channels (502) are provided on the inner wall of the insertion cavity (501). The upper end of the support plate (5) is fixedly connected to the plug tube (9), and the upper end of the plug tube (9) is inserted into the inner wall of the mounting tube (6). The support plate (5), the mounting tube (6) and the plug tube (9) together form an annular cavity (603). The support plate (5) is provided with multiple upward channels (503) evenly distributed in a circle. The upward channels (503) are used to connect the annular cavity (603) and the inner cavity of the collection cover (8). The outer wall of the mounting tube (6) is provided with an exhaust hole (602) connecting the annular cavity (603) and the inner cavity of the quartz cap (302).

2. The apparatus for doping carbon into a gallium arsenide single crystal according to claim 1, wherein The mounting cylinder (6) is a hollow cylindrical structure with an open bottom. A threaded post (601) integrally formed with it is fixedly connected to the center of the upper end of the mounting cylinder (6). A threaded cylinder (303) integrally formed with it is fixedly connected to the center of the inner wall of the quartz cap (302). The threaded post (601) and the threaded cylinder (303) are threadedly matched. The bearing plate (5) is a disc-shaped structure. The bearing plate (5) is located on the outside of the upper flow channel (503) and has a threaded groove (504). The lower end of the mounting cylinder (6) is provided with a threaded protrusion that matches its threaded groove (504). The plug-in cylinder (9) is a hollow cylindrical structure with an open top and bottom. The top wall of the mounting cylinder (6) is provided with a plug-in groove (605) for the upper end of the plug-in cylinder (9) to be inserted.

3. The apparatus for doping carbon into a gallium arsenide single crystal according to claim 1, wherein The graphite column (7) includes an upper cylindrical part (701), a frustum part (702) is fixedly connected to the lower end of the upper cylindrical part (701), a lower cylindrical part (703) is fixedly connected to the lower end of the frustum part (702), the lower part of the upper cylindrical part (701) and the conical sidewall of the frustum part (702) are in contact with the inner wall of the insertion cavity (501), and the lower cylindrical part (703) extends into the collection hood (8).

4. The apparatus for doping carbon into a gallium arsenide single crystal according to claim 3, wherein The diameter of the lower cylindrical part (703) is smaller than the diameter of the lower opening of the insertion cavity (501). An annular gap is formed between the outer wall of the lower cylindrical part (703) and the inner wall of the lower opening of the insertion cavity (501) to allow the reaction gas and stripping particles to pass through. The exhaust channel (502) is connected to the annular gap.

5. The apparatus for doping carbon according to claim 1, wherein Multiple vertically distributed flow-blocking rings (604) are fixedly connected to the inner wall of the mounting cylinder (6). The flow-blocking rings (604) are annular structures with their inner ends facing downwards, and the flow-blocking rings (604) are set in the annular cavity (603).

6. The apparatus for doping carbon according to claim 1, wherein The lower end face of the bearing plate (5) is fixedly connected to a concentrically arranged guide cylinder one (11) and guide cylinder two (12). Guide cylinder one (11) is connected to the insertion cavity (501) and is horn-shaped. Guide cylinder two (12) is cylindrical. The diameter of guide cylinder two (12) is smaller than the diameter of the lower end of guide cylinder one (11). The lower opening of the upper flow channel (503) is located between guide cylinder one (11) and guide cylinder two (12).

7. The apparatus for doping carbon according to claim 6, wherein The collection cover (8) has a hollow hemispherical structure, and a thickening block (13) is fixedly connected to the center of its bottom. A conical cavity is opened at the upper end of the thickening block (13).

8. The apparatus for doping carbon according to claim 7, wherein The outer wall of the plug tube (9) is fitted with multiple trays (901) located on the same horizontal plane. The upper end of the tray (901) abuts against a porous quartz filter ring (10) disposed in the annular cavity (603). The installation height of the porous quartz filter ring (10) is lower than the opening height of the exhaust hole (602).

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