A novel CVD bubbling device

Abstract

The utility model discloses a novel CVD bubbling device, it includes storage tank and bubbling jar, the storage tank with bubbling jar is passed feed pipe intercommunication, the bubbling jar is provided with air inlet pipeline and air outlet pipeline, the air outlet of air inlet pipeline is located bubbling jar's liquid level below, the air inlet of air outlet pipeline is located bubbling jar's liquid level above, the bubbling jar still is provided with manometer, and the manometer is used for measuring the air pressure in bubbling jar, the bubbling jar still is provided with exhaust pipe, the air inlet of exhaust pipe is located bubbling jar's liquid level above, is provided with valve and air pressure adjusting mechanism on exhaust pipe, and the air pressure adjusting mechanism is located the downstream of valve, the air pressure adjusting mechanism includes the conical tube of vertical arrangement and the round ball in conical tube. The utility model is favorable for avoiding or alleviating the problem of bubbling jar pressure instability when MTS raw material supplement, and it is helpful to improve the uniformity of CVD coating.

Description

Technical Field

[0001] This utility model relates to a novel CVD bubbling device, belonging to the field of chemical vapor deposition technology. Background Technology

[0002] With the rapid development of the photovoltaic and semiconductor markets, CVD (Chemical Vapor Deposition) technology is being used more and more. In particular, the market demand for CVD silicon carbide coated graphite products is increasing. Different application scenarios result in significant differences in the thickness of the CVD silicon carbide film on the graphite product surface, ranging from 5μm to 1000μm. Currently, the mainstream CVD silicon carbide process mainly uses the monomethyltrichlorosilane (MTS) system. However, at room temperature, MTS is a volatile liquid and undergoes violent hydrolysis upon contact with air, generating highly corrosive hydrogen chloride gas. Therefore, during the growth of CVD silicon carbide coated films, a continuous supply of raw materials is required in a clean, closed system to obtain high-purity silicon carbide films. Especially for the preparation of thick silicon carbide coatings, long-term uninterrupted chemical vapor deposition is necessary. As the process time increases, the risk of instability in the delivery of the MTS liquid raw material is greatly increased.

[0003] In existing technologies, most methods employ bubblers to transport MTS feedstock. This involves using a carrier gas to bubble out the MTS feedstock gas, while liquid MTS feedstock is injected into the bubbler. As bubbling progresses, the liquid MTS feedstock is continuously consumed, causing changes in its level. When the level drops, the pressure inside the bubbler decreases; when the level reaches its minimum, MTS feedstock is automatically added back into the bubbler, causing the level to rise and the pressure inside the bubbler to increase. Therefore, the replenishment process of MTS feedstock leads to inconsistent pressure within the bubbler, affecting the Si source input to the reaction chamber and potentially causing uneven SiC coating, resulting in areas with partial Si-rich and partial C-rich areas. Utility Model Content

[0004] To overcome the problems existing in the prior art, this utility model provides a novel CVD bubbling device, which helps to alleviate the problem of uneven coating caused by unstable pressure during MTS raw material replenishment. The specific technical solution is as follows.

[0005] A novel CVD bubbling device includes a storage tank and a bubbling tank, which are connected by a feed pipe. The bubbling tank is equipped with an air inlet pipe and an air outlet pipe. The air outlet of the air inlet pipe is located below the liquid surface in the bubbling tank, and the air inlet of the air outlet pipe is located above the liquid surface in the bubbling tank. Its features are:

[0006] The bubbling tank is also equipped with a pressure gauge for measuring the air pressure inside the bubbling tank; the bubbling tank is also equipped with an exhaust pipe, the air inlet of which is located above the liquid surface in the bubbling tank, and the exhaust pipe is equipped with a valve and an air pressure regulating mechanism, the air pressure regulating mechanism being located downstream of the valve;

[0007] The air pressure regulating mechanism includes a vertically arranged conical tube and a sphere located inside the conical tube.

[0008] Using the above technical solution, when the liquid level in the bubbling tank drops to a certain level, the storage tank must be used to replenish the raw material in the bubbling tank; otherwise, the raw material carried out by the carrier gas through the air inlet pipe will not meet the set requirements. The rapid entry of liquid raw material from the storage tank into the bubbling tank will cause a sudden increase in pressure inside the bubbling tank, resulting in uneven supply of raw material to the reaction chamber. In the technical solution of this application, when the pressure detected by the pressure gauge exceeds the set threshold, the valve is opened to quickly release a portion of the gas, thereby rapidly restoring the pressure inside the bubbling tank to a normal level, thus achieving pressure stability during the replenishment process. The pressure regulating mechanism includes a conical tube and a sphere. The weight of the sphere is precisely suited to the normal pressure inside the bubbling tank. Pressures higher than this normal pressure can push the sphere open, while pressures equal to or lower than this normal pressure are insufficient to push it open. The pressure regulating mechanism has two functions: First, when some gas is discharged from the exhaust pipe and the pressure inside the bubbling tank returns to normal, the sphere blocks the exhaust pipe, preventing excessive gas discharge before the valve closes, thus preventing the pressure inside the bubbling tank from falling below normal. Second, the pressure regulating mechanism serves as a redundant design for the pressure gauge, ensuring that even if the pressure gauge deviates (for example, when the pressure inside the bubbling tank is normal, but the pressure gauge detects a pressure higher than normal), the gas inside the bubbling tank is not incorrectly discharged.

[0009] Furthermore, the bubbling tank is also equipped with a level gauge, which is used to detect the liquid level height inside the bubbling tank.

[0010] Furthermore, it also includes a controller, and the level gauge, pressure gauge, and valve are electrically connected to the controller. When the level gauge detects that the liquid level is insufficient, the controller controls the storage tank to replenish the bubbling tank. When the pressure gauge detects that the pressure is higher than the set value, the controller opens the valve to vent the gas through the vent pipe.

[0011] Furthermore, the valve is either a solenoid valve or a pneumatic valve. Solenoid valves or pneumatic valves are advantageous for achieving automatic control.

[0012] Furthermore, the storage tank is equipped with an inert gas pipe, the outlet of which is located above the liquid surface in the storage tank, while the inlet of the feed pipe is located below the liquid surface in the storage tank. The controller can control the connection or disconnection of the inert gas pipe. When the inert gas pipe is open, the inert gas input into the storage tank increases the gas pressure inside the tank, thereby forcing the liquid raw material in the storage tank into the bubbling tank through the feed pipe.

[0013] Furthermore, the gas transported in the intake pipe is hydrogen.

[0014] Furthermore, the bubbling tank and / or the storage tank are equipped with an insulating jacket. The insulating jacket helps to keep the temperature of the liquid raw material at a relatively constant level.

[0015] Compared with the prior art, this invention helps to avoid or alleviate the problem of unstable pressure in the bubbling tank during MTS raw material replenishment, and helps to improve the uniformity of CVD coating. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the novel CVD bubbling device of this utility model.

[0017] In the diagram: 1. Storage tank; 2. Bubbling tank; 3. Feed pipe; 4. Air inlet pipe; 5. Air outlet pipe; 6. Pressure gauge; 7. Exhaust pipe; 8. Valve; 9. Conical tube; 10. Sphere; 11. Level gauge; 12. Controller; 13. Inert gas pipe; 14. Liquid raw material. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings.

[0019] See Figure 1 The novel CVD bubbling device includes a storage tank 1 and a bubbling tank 2, which are connected by a feed pipe 3. The bubbling tank 2 is equipped with an air inlet pipe 4 and an air outlet pipe 5. The air outlet of the air inlet pipe 4 is located below the liquid surface of the bubbling tank 2, and the air inlet of the air outlet pipe 5 is located above the liquid surface of the bubbling tank 2.

[0020] The bubbling tank 2 is also equipped with a pressure gauge 6, which is used to measure the air pressure inside the bubbling tank 2; the bubbling tank 2 is also equipped with an exhaust pipe 7, the air inlet of the exhaust pipe 7 is located above the liquid surface of the bubbling tank 2, and the exhaust pipe 7 is equipped with a valve 8 and an air pressure regulating mechanism, the air pressure regulating mechanism being located downstream of the valve 8.

[0021] The air pressure regulating mechanism includes a vertically arranged conical tube 9 and a sphere 10 located inside the conical tube 9. The sphere 10 can be made of steel or other suitable materials.

[0022] Preferably, the bubbling tank 2 is also equipped with a level gauge 11, which is used to detect the liquid level in the bubbling tank 2.

[0023] To achieve automatic control, the bubbling device also includes a controller 12, with a level gauge 11, a pressure gauge 6, and a valve 8 electrically connected to the controller 12. When the level gauge 11 detects insufficient liquid level, the controller 12 controls the storage tank 1 to replenish the bubbling tank 2. When the pressure gauge 6 detects pressure exceeding a set value, the controller 12 opens the valve 8 to vent air through the exhaust pipe 7. Preferably, the valve 8 is a solenoid valve or a pneumatic valve. Solenoid valves or pneumatic valves facilitate automatic control.

[0024] Storage tank 1 is equipped with an inert gas pipe 13. The outlet of the inert gas pipe 13 is located above the liquid surface in storage tank 1, while the inlet of the feed pipe 3 is located below the liquid surface in storage tank 1. The controller 12 can control the connection or disconnection of the inert gas pipe 13. When the inert gas pipe 13 is open, the inert gas input into storage tank 1 increases the gas pressure in storage tank 1, thereby forcing the liquid raw material 14 in storage tank 1 into the bubbling tank 2 through the feed pipe 3.

[0025] The gas transported in the inlet pipe 4 is hydrogen. The hydrogen serves as a carrier gas and, through bubbling, transports the liquid raw material 14 to the downstream reaction chamber (not shown) via the outlet pipe 5.

[0026] In order to keep the temperature of the liquid raw material 14 constant, a heat insulation jacket (not shown) can be installed on the body of the bubbling tank 2 and / or the storage tank 1. The heat insulation jacket helps to ensure that the temperature of the liquid raw material is kept in a roughly constant state.

[0027] The working principle of this invention is as follows: When the liquid level in the bubbling tank 2 drops to a certain level, the storage tank 1 must be used to replenish the raw material in the bubbling tank 2; otherwise, the amount of raw material carried out by the carrier gas through the air inlet pipe 4 will not meet the set requirements. The rapid entry of liquid raw material from the storage tank 1 into the bubbling tank 2 will cause a sudden increase in pressure within the bubbling tank 2, easily leading to uneven supply of raw material to the reaction chamber. When the pressure detected by the pressure gauge 6 exceeds the set threshold, the valve 8 is opened to quickly release a portion of the gas, thereby rapidly restoring the pressure in the bubbling tank 2 to a normal level, thus achieving pressure stability during the replenishment process. The pressure regulating mechanism includes a conical tube 9 and a sphere 10. The weight of the sphere 10 is just right to match the normal pressure inside the bubbling tank 2. Pressures higher than this normal pressure can push the sphere 10 open, while pressures equal to or lower than this normal pressure are insufficient to push the sphere 10 open. The pressure regulating mechanism has two functions: First, when some gas is discharged from the exhaust pipe 7 and the pressure inside the bubbling tank 2 returns to normal, the sphere 10 blocks the exhaust pipe 7, preventing excessive gas discharge before the valve 8 closes, thus preventing the pressure inside the bubbling tank 2 from falling below the normal pressure. Second, the pressure regulating mechanism can serve as a redundant design for the pressure gauge 6, ensuring that gas inside the bubbling tank 2 is not mistakenly discharged even when the pressure gauge 6 deviates (for example, when the pressure inside the bubbling tank 2 is normal, but the pressure gauge 6 detects a pressure higher than normal).

[0028] The embodiments of the present invention have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention is not limited to the specific embodiments described above; these embodiments are merely illustrative and not limiting. Those skilled in the art, under the guidance of the present invention, can make many modifications without departing from the spirit and scope of the claims, and all such modifications fall within the protection scope of the present invention.

Claims

1. A novel CVD bubbling device, comprising a storage tank (1) and a bubbling tank (2), wherein the storage tank (1) and the bubbling tank (2) are connected by a feed pipe (3), the bubbling tank (2) is provided with an air inlet pipe (4) and an air outlet pipe (5), wherein the air outlet of the air inlet pipe (4) is located below the liquid surface of the bubbling tank (2), and the air inlet of the air outlet pipe (5) is located above the liquid surface of the bubbling tank (2); characterized in that: The bubbling tank (2) is also equipped with a pressure gauge (6), which is used to measure the air pressure inside the bubbling tank (2); the bubbling tank (2) is also equipped with an exhaust pipe (7), the air inlet of the exhaust pipe (7) is located above the liquid surface of the bubbling tank (2), and the exhaust pipe (7) is equipped with a valve (8) and an air pressure regulating mechanism, the air pressure regulating mechanism being located downstream of the valve (8); The air pressure regulating mechanism includes a vertically arranged conical tube (9) and a sphere (10) located inside the conical tube (9).

2. The novel CVD bubbling device according to claim 1, characterized in that, The bubbling tank (2) is also equipped with a level gauge (11), which is used to detect the liquid level in the bubbling tank (2).

3. The novel CVD bubbling device according to claim 2, characterized in that, It also includes a controller (12), the level gauge (11), the pressure gauge (6) and the valve (8) being electrically connected to the controller (12).

4. A novel CVD bubbling device according to claim 1, characterized in that, The valve (8) is a solenoid valve or a pneumatic valve.

5. A novel CVD bubbling device according to claim 1, characterized in that, The storage tank (1) is equipped with an inert gas pipe (13), the outlet of the inert gas pipe (13) is located above the liquid surface of the storage tank (1), and the inlet of the feed pipe (3) is located below the liquid surface of the storage tank (1).

6. A novel CVD bubbling device according to claim 1, characterized in that, The gas transported in the intake pipe (4) is hydrogen.

7. A novel CVD bubbling device according to claim 1, characterized in that, The bubbling tank (2) and / or the storage tank (1) are provided with heat-insulating jackets.

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