Epitaxial equipment

Abstract

The extension equipment comprises a quartz air inlet square pipe, an induction coil, an upper half-moon heating seat, a lower half-moon heating seat, an upstream heat preservation cover and a downstream heat preservation cover, the upper half-moon heating seat and the lower half-moon heating seat are symmetrically arranged, and the upstream heat preservation cover and the downstream heat preservation cover are arranged at the two ends of the upper half-moon heating seat and the two ends of the lower half-moon heating seat. The upper half-moon heating base and the lower half-moon heating base are each of a hollow half-moon structure which comprises an arc face and a plane and is provided with openings in the two ends, and the two sides of the plane of the upper half-moon heating base and the two sides of the plane of the lower half-moon heating base are connected through insulating parts. The planes of the upper half-moon heating base and the lower half-moon heating base and the upstream ends of the two insulating parts extend outwards to penetrate through a through hole in the middle of the upstream heat preservation cover to be connected with a quartz air inlet square pipe, the extending parts of the upper half-moon and the lower half-moon are located in the induction coil, and the quartz air inlet square pipe is located outside the induction coil. The upper half-moon plane and the lower half-moon plane extend outwards to reconstruct the heating body structure, and generation of by-products is effectively relieved on the basis that the center temperature gradient of the wafer is guaranteed.

Description

Technical Field

[0001] This invention relates to the structure of compound epitaxial furnaces, CVD coating equipment, etc., and more specifically to a heating element structure for an epitaxial equipment. Background Technology

[0002] like Figure 1 and Figure 2 As shown, in the SiC epitaxial process, the horizontal air intake device usually uses high-purity graphite as the material for the upper half-moon 3 and lower half-moon 7 of the induction heating element. The upper half-moon 3 and lower half-moon 7 are connected by side insulating plates (8 and 9). In addition, the base 5 that supports the wafer, the protective parts (4 and 6) on the surface of the heating element, and the graphite air intake transition tube 2 are all made of high-purity graphite. The upper half-moon 3 and lower half-moon 7 of the graphite heating element and the graphite air intake transition tube 2 are located inside the coil. The precursor (usually a silicon source such as TCS or a carbon source such as C2H4) generally enters the chamber through the quartz air intake square tube 1.

[0003] Due to the extremely high process temperature (typically above 1500℃), the graphite transition tube 2 located within the induction coil generates self-heat, and the reaction precursor has strong reactivity. While the SiC epitaxial layer grows on the wafer, the reactive gas also undergoes unexpected parasitic chemical reactions on the graphite substrate and other graphite components, depositing a polycrystalline or amorphous SiC byproduct coating. If too many byproducts are generated, on the one hand, a lot of time is required for maintenance, affecting the production cycle; on the other hand, it affects the stability of the intake airflow, the ion concentration on the wafer surface, and the distribution and uniformity of the coating thickness. In addition, the byproducts deposited on the inner surface of the upper half of the wafer may fall off during the process due to gravity and airflow, affecting the surface quality of the product.

[0004] Regarding the current situation of byproduct deposition on graphite components during the reaction process, existing technologies lack particularly effective improvement measures. Generally, a physical barrier is established by depositing a SiC thin film on the graphite surface. Additionally, in equipment such as PECVD, process gases such as hydrogen (H2) or nitrogen (N2) are introduced before or periodically into the deposition boat, and radio frequency power is applied to generate plasma. This plasma can chemically react with byproducts such as the fluorocarbon film deposited on the graphite boat surface, generating volatile gases such as hydrogen fluoride (HF), which are then removed by a vacuum system, thus achieving cleaning. However, existing technical solutions do not fundamentally solve the problem of byproduct formation on the graphite surface and are costly and cumbersome. Summary of the Invention

[0005] Purpose of the invention: To address the above-mentioned shortcomings, the present invention provides an epitaxial device for reducing graphite surface deposition.

[0006] Technical Solution: To solve the above problems, the present invention employs an epitaxial device, including a quartz inlet square tube, an induction coil, an upper half-moon heating seat, a lower half-moon heating seat, an upstream insulation cover, and a downstream insulation cover. The upper and lower half-moon heating seats are symmetrically arranged, and the upstream and downstream insulation covers are located at both ends of the upper and lower half-moon heating seats. Both the upper and lower half-moon heating seats are hollow half-moon structures with openings at both ends, including an arc surface and a plane. The two sides of the plane of the upper and lower half-moon heating seats are connected by insulating components. The plane of the upper and lower half-moon heating seats and the upstream ends of the two insulating components extend outward through a through hole in the middle of the upstream insulation cover and connect to the quartz inlet square tube. The upper half-moon heating seat, the lower half-moon heating seat, the upstream insulation cover, and the downstream insulation cover are all located inside the induction coil, and the quartz inlet square tube is located outside the induction coil.

[0007] Furthermore, both the upper and lower half-moon heating bases have a heating section and an extension section on their planes. The heating section is connected to the arc surface, and the extension section passes through the through hole in the middle of the upstream insulation cover. The thickness of the extension section is the same as the wall thickness of the upper and lower walls of the quartz air inlet square tube. The size of the air inlet channel formed between the extension sections of the upper and lower half-moon heating bases is the same as the size of the air inlet channel of the quartz air inlet square tube.

[0008] Furthermore, the insulating component includes a base and an extended portion. The base of the insulating component is connected to the heating portion of the plane of the upper and lower half-moon heating seats. The extended portion of the insulating component is connected to the extension portion of the plane of the upper and lower half-moon heating seats. The left and right walls of the extended portion of the insulating component have the same wall thickness. The size of the air intake channel formed between the two extended portions of the insulating component is the same as the size of the air intake channel of the quartz air intake tube.

[0009] Furthermore, the quartz air inlet square tube is provided with two horizontal baffles and two vertical baffles. The two horizontal baffles are arranged parallel to each other vertically, and the two vertical baffles are perpendicular to the horizontal baffles and arranged parallel to each other. The two vertical baffles divide the quartz air inlet tube into a first side air inlet channel, a horizontal middle air inlet channel and a second side air inlet channel in the horizontal direction. The two horizontal baffles divide the first side air inlet channel, the horizontal middle air inlet channel and the second side air inlet channel of the quartz air inlet tube into an upper air inlet channel, a vertical middle air inlet channel and a lower air inlet channel in the vertical direction. The upper air inlet channel is used to introduce carrier gas, and the middle air inlet channel and the lower air inlet channel are used to introduce special gas.

[0010] Furthermore, the height of the upper air intake channel is greater than that of the middle air intake channel, and the height of the middle air intake channel is greater than that of the lower air intake channel.

[0011] Furthermore, the height difference between the middle air intake channel and the upper air intake channel is the same as the height difference between the lower air intake channel and the middle air intake channel.

[0012] Furthermore, the height difference between the middle and upper air intake channels and between the lower and middle air intake channels ranges from 1 to 3 mm.

[0013] Beneficial Effects: Compared to existing technologies, this invention effectively mitigates byproduct formation by reconstructing the upper and lower hemispheres of the heating element structure while maintaining the temperature gradient at the wafer center. Through a novel vertically layered air intake structure, a carrier gas curtain is constructed to block the diffusion path of the special gas to the hemisphere surface, thereby reducing the reaction intensity. By employing a novel heating element structure and matching it with a novel air intake system, this invention addresses the two key elements of the reaction (reaction temperature and reactant concentration), reducing byproduct formation on the graphite surface. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the epitaxial device in the existing technical solution.

[0015] Figure 2 This is a cross-sectional view of the extension device in the existing technical solution.

[0016] Figure 3 This is a schematic diagram of the heating element structure of the epitaxial device in this invention.

[0017] Figure 4 Cloud map showing the distribution of eddy current loss on the equipment facade in existing technical solutions.

[0018] Figure 5 This is a cloud map showing the temperature distribution on the equipment facade in the existing technical solution.

[0019] Figure 6 This is a cloud map showing the temperature distribution on the wafer surface in existing technical solutions.

[0020] Figure 7 (a) in the figure is a temperature cloud map of the surface of the protective component in the prior art solution. Figure 6 (b) in the figure is a cloud map of the by-product deposition rate on the surface of the protective component in the prior art.

[0021] Figure 8 (a) in the figure is a temperature cloud map of the lower surface of the moon in the first half of the month in the existing technical solution. Figure 7 (b) in the figure is a cloud map of the by-product deposition rate on the lower surface of the upper half of the moon in the prior art.

[0022] Figure 9 This is a cloud map showing the eddy current loss distribution on the facade of the extension equipment in this invention.

[0023] Figure 10This is a cloud map showing the temperature distribution on the facade of the extension equipment in this invention.

[0024] Figure 11 This is a cloud map showing the temperature distribution on the wafer surface in this invention.

[0025] Figure 12 (a) in the figure is a temperature cloud map of the surface of the protective component in this invention. Figure 12 (b) in the figure is a cloud map of the by-product deposition rate on the surface of the protective component in this invention.

[0026] Figure 13 (a) in the figure is the temperature cloud map of the lower surface of the upper half of the month in this invention. Figure 13 (b) is a cloud map of the by-product deposition rate on the lower surface of the upper half of the moon in this invention.

[0027] Figure 14 This is a schematic diagram of the structure of the quartz air intake square tube of the present invention, which is divided into three air intake channels: upper, middle and lower.

[0028] Figure 15 This is a deposition cloud map of the lower surface of the upper half of the moon when the gas contains special gases, as described in this invention.

[0029] Figure 16 This is a cloud map of AsH3 concentration when the present invention contains a special gas.

[0030] Figure 17 This is a deposition cloud map of the lower surface of the upper half of the moon when there is no special gas on the road.

[0031] Figure 18 This is a cloud map of AsH3 concentration when no special gas is available on the road surface according to the present invention.

[0032] Figure 19 This is a deposition cloud map of the lower surface of the upper half of the moon when the upper path is offset downwards and contains special gas.

[0033] Figure 20 This is a cloud map of AsH3 concentration when the upper path of the middle path is offset downwards and contains special gas, as shown in the present invention.

[0034] Figure 21 This is a deposition cloud map of the lower surface of the upper half of the moon when the middle path is shifted downwards and the upper path has no special gas.

[0035] Figure 22 This is a cloud map of AsH3 concentration when the middle path is shifted downwards and the upper path has no special gas.

[0036] Figure 23 This is a deposition cloud map of the lower surface of the upper half of the moon when the upper path is offset upwards and contains special gas, according to the present invention.

[0037] Figure 24 This is a cloud map of AsH3 concentration when the upper path of the intermediate path in this invention contains a special gas.

[0038] Figure 25 This is a deposition cloud map of the lower surface of the upper half of the moon when there is no special gas in the upper path of the central path in this invention.

[0039] Figure 26 This is a cloud map of AsH3 concentration when there is no special gas in the upper channel of the central channel in this invention.

[0040] Figure 27 This is a comparison chart of the deposition rate of by-products on the lower surface during the first half of the month when there is no special gas on the road surface according to the present invention.

[0041] Figure 28 This is a comparison chart of the total amount of deposition on the lower surface during the first half of the month when there is no special gas on the road and different offsets.

[0042] Figure 29 This is a comparison chart of the deposition rate on the lower surface of the first half of the month when the surface contains special gas and has different offsets.

[0043] Figure 30 This is a comparison chart of the deposition rate on the lower surface during the first half of the month when there is no special gas on the road and different offsets. Detailed Implementation

[0044] like Figure 3 As shown, in this embodiment, an epitaxial device includes a quartz inlet square tube, an induction coil, an upper half-moon heating seat, a lower half-moon heating seat, an upstream insulation cover, and a downstream insulation cover. The upper and lower half-moon heating seats are symmetrically arranged. The upstream and downstream insulation covers are located at both ends of the upper and lower half-moon heating seats. Both the upper and lower half-moon heating seats are hollow crescent structures with openings at both ends, including an arc surface and a plane. The two sides of the plane of the upper and lower half-moon heating seats are connected by insulating parts. The plane of the upper and lower half-moon heating seats and the upstream ends of the two insulating parts extend outward through the through hole in the middle of the upstream insulation cover and connect with the quartz inlet square tube. The upper half-moon heating seat, the lower half-moon heating seat, the upstream insulation cover, and the downstream insulation cover are all located inside the induction coil, and the quartz inlet square tube is located outside the induction coil.

[0045] The upper and lower half-moon heating bases each include a heating part 21 and an extension part 22 on their flat surfaces. The heating part 21 is connected to the arc surface. The extension part 22 passes through the through hole in the middle of the upstream insulation cover. The thickness of the extension part is the same as the wall thickness of the upper and lower walls of the quartz air inlet square tube. The size of the air inlet channel formed between the extension parts of the upper and lower half-moon heating bases is the same as the size of the air inlet channel of the quartz air inlet square tube.

[0046] The insulating component includes a base 31 and an extension 32. The base 31 of the insulating component is connected to the heating portion 21 of the plane of the upper half-moon heating seat and the lower half-moon heating seat. The extension 32 of the insulating component is connected to the extension portion 22 of the plane of the upper half-moon heating seat and the lower half-moon heating seat. The left and right walls of the quartz air inlet square tube of the extension portion of the insulating component have the same wall thickness. The size of the air inlet channel formed between the two extension portions of the insulating component is the same as the size of the air inlet channel of the quartz air inlet square tube.

[0047] Compared with the prior art, the heating element structure of this embodiment eliminates the graphite air inlet transition plate, integrates the upper and lower plates of the transition section with the upper and lower crescents, and uses insulating parts on both sides of the upper and lower plates of the transition section to form an air passage with the upper and lower plates.

[0048] In this embodiment, CFD calculations are performed on the internal temperature and flow field of the device based on the heating element structure before and after the improvement. Figures 4 to 8 As shown, based on the existing heating element structure, when the wafer center temperature is controlled at a specific temperature, the internal thermal magnetic field of the device is calculated using CFD. (The following is a partial translation based on the provided text.) Figure 4 The eddy current loss distribution cloud map of the equipment facade shown indicates that the upper half of the inner surface is a high-loss region due to the skin effect of induction heating; according to... Figure 5 The temperature distribution cloud map of the equipment facade shown indicates that the inner surface is the second highest temperature zone in the first half of the month; according to... Figure 6 The temperature distribution cloud map on the wafer surface shown indicates an intra-wafer temperature difference of 11.64℃; according to... Figure 7 The temperature cloud map, by-product deposition rate cloud map, and other data shown in (a) and (b) above represent the surface of the protective component. Figure 8 The temperature cloud map and by-product deposition rate cloud map of the lower surface of the upper half of the moon shown in (a) and (b) show that the average temperature of the protective part surface is 1483.9℃ and the in-plane integral deposition rate is 4.69e-6 kg / s, and the average temperature of the lower surface of the upper half of the moon is 1520.8℃ and the in-plane integral deposition rate is 1.07e-5 kg / s.

[0049] like Figures 9 to 13 As shown, based on the heating element structure in this embodiment, the temperature at the center of the wafer is controlled at a specific temperature (while the aforementioned specific temperature is also present). The internal temperature magnetic field CFD calculation results of the device are then used to determine the appropriate parameters. Figure 9 The eddy current loss distribution cloud map of the equipment facade shown is compared with... Figure 4 The loss cloud diagram of the existing technology structure shows that after the upper and lower half-moon heating seats are extended, the cross-sectional area through which the circular current generated by electromagnetic induction passes increases. Under the premise that the overall loss of the upper half-moon heating seat is consistent, its heating in the internal region of the reaction chamber decreases; according to... Figure 10 The temperature distribution cloud map of the equipment facade shown is consistent with... Figure 5 The temperature distribution is similar in the middle, with the inner surface being the second-highest temperature zone in the first half of the month; according to... Figure 11 The temperature distribution cloud map of the wafer surface shown indicates an intra-wafer temperature difference of 11.1℃, which is comparable to the intra-wafer temperature difference data of existing technology structures; according to... Figure 12 The temperature cloud maps and by-product deposition rate cloud maps of the protective component surface shown in (a) and (b) indicate that the surface temperature of the protective component exhibits a distribution pattern of high temperature in the middle and low temperature on both sides. The average in-plane temperature is 1481.2℃, which is 2.7℃ lower than the existing technology structure (1483.9℃). The by-product deposition pattern is similar to the temperature distribution, with an overall in-plane by-product deposition rate of 4.55e-6 kg / s, which is 2.98% lower than the existing technology structure (4.69e-6 kg / s). According to... Figure 13 The temperature cloud map and by-product deposition rate cloud map of the lower surface of the upper half of the moon shown in (a) and (b) show that the temperature distribution of the lower surface of the upper half of the moon is high in the middle and low on both sides. The average temperature in the surface is 1519.7℃, which is 1.1℃ lower than the existing technology structure (1520.8℃). The by-product deposition is close to the temperature distribution. The in-plane integral deposition rate is 1.01e-5kg / s, which is 5.61% lower than the existing technology structure (1.07e-5kg / s).

[0050] The precursor typically enters the chamber through a quartz inlet square tube. The inside of the quartz square tube is horizontally divided into three channels by vertical partitions: a first side inlet channel, a horizontal middle inlet channel, and a second side inlet channel. Then, different precursor and carrier gas ratios are set according to the process. In this embodiment, for example... Figure 14 As shown, two horizontal baffles are installed inside the quartz air inlet square tube 1. The two horizontal baffles are arranged parallel to each other in the vertical direction. The two horizontal baffles divide the first side air inlet channel, the horizontal middle air inlet channel and the second side air inlet channel of the quartz air inlet tube into three air inlet channels in the height direction: upper, middle and lower. The upper air inlet channel 11 is used to introduce carrier gas, and the middle air inlet channel 12 and the lower air inlet channel 13 are used to introduce special gas.

[0051] In this embodiment, the precursor enters the chamber through a quartz inlet square tube. Taking the precursors arsine (AsH3) and trimethylgallium (Ga(CH3)3) as electronic specialty gases as an example, the generated deposits are arsenic (As) and gallium (Ga), respectively. Based on the structure of the quartz inlet square tube 1, the precursor ratio of the upper inlet channel 11 is adjusted to study the deposition on the lower surface of the upper half of the moon. In actual processes, the lower inlet channel needs to be circulated with specialty gases as the deposition source for the wafer. However, whether the lower inlet channel is circulated with specialty gases has little impact on the deposition on the lower surface of the upper half of the moon. Moreover, the core of this embodiment is to reduce the deposition in the upper half of the moon. Therefore, this embodiment adopts a simplified study by not circulating specialty gases in the lower inlet channel. The preliminary ratio of the three gases is shown in Table 1. The ratio of the three gases in the upper inlet channel 11 without specialty gases is shown in Table 2.

[0052] Table 1 Initial Ratio - Special Gas Included on the Road

[0053]

[0054] Table 2 Change ratio - No special gas on the road

[0055]

[0056] According to the initial ratio in Table 1, when the upper and middle channels contain special gas and the lower channel contains pure carrier gas, such as... Figure 15 and Figure 16 As shown, due to the wall effect, the special gas accumulates towards the lower surface of the upper half of the moon, forming a high-concentration zone at its front end where a large amount of byproducts are deposited; such as Figure 27 As shown, subsequently, under the effect of diffusion, the concentration of the special gas gradually decreases, and the deposition rate of by-products decreases accordingly; according to the change ratio in Table 2, under the premise of ensuring the total concentration of the special gas in the intake and that there is no special gas in the upper channel, the pure carrier gas in the upper and lower channels forms two air curtains, such as Figure 17 and Figure 18 As shown, the special gas diffuses to both sides along its inherent path after exiting the central channel; as... Figure 27 Comparing the by-product deposition rate distribution under the initial ratio and the changed ratio, it can be seen that by layering the upper and lower parts and adjusting the ratio of special gas, the deposition rate on the lower surface in the first half of the month can be significantly reduced.

[0057] With the total height of the square tube set at 3n mm, and ensuring the following conditions, a CFD simulation study was conducted using the total amount of by-products deposited on the lower surface of the upper half of the moon as the evaluation index:

[0058] (1) The height of the middle lane is fixed at n. Assuming the middle lane is offset by x mm to adjust the height of the upper and lower lanes, the height ratios of the three lanes are nx:n:n+x;

[0059] (2) The total flow rate of the three gases, the two special gases AsH3 and Ga(CH3)3, and the total amount of H2 remain unchanged.

[0060] like Figures 19 to 22 When the middle channel shifts downwards as a whole, the upper channel may or may not contain special gas, such as... Figures 23 to 26 The upper channel may contain special gas or not when the middle channel is shifted upwards.

[0061] Combination Figures 19 to 30It can be seen that regardless of the value of x (offset distance), when there is no special gas in the upper channel, the total amount of by-products deposited on the lower surface in the first half of the month is less than that under the condition containing special gas. When there is special gas in the upper channel, the overall upward shift of the middle channel (x>0) indicates that the upper channel height narrows, causing the upper channel velocity to increase, while the lower channel height increases, causing the lower channel velocity to decrease. Due to the wall effect and pressure difference, the entire inflow into the equipment quickly reaches the wall under the action of the upper channel airflow, and a high-concentration zone is formed at the front end, where a large amount of by-products are deposited. The narrower the upper channel, the earlier the by-products are deposited on the lower surface in the first half of the month. A more vigorous reaction results in more deposited byproducts, while a slower reaction occurs later in the second half of the month, resulting in a smaller total amount of byproducts. When there is no special gas in the upper channel, the overall upward shift of the middle channel indicates that the upper channel is narrowing and the flow velocity is increasing. Firstly, the special gas in the middle channel is closer to the wall, making it easier for byproducts to deposit. Secondly, the increased flow velocity in the upper channel, under the influence of pressure difference, makes it easier for the special gas in the middle channel to be adsorbed onto the wall. Under these two factors, the narrower the upper channel, the earlier the special gas reaches the lower surface of the first half of the month and reacts, resulting in more deposited byproducts. Conversely, the later the gas reaches the lower surface of the second half of the month, the smaller the total amount of byproducts produced.

[0062] Combination Figures 19 to 30 When x < 0 (the middle channel shifts downward, the upper channel widens, and the lower channel narrows), it is more helpful in reducing by-product deposition. However, when the lower channel is too narrow, the flow velocity below is too high. When the lower airflow passes through the front guard, it will form a large number of vortices on the wafer surface under the effect of its slope angle, affecting the wafer epitaxial process. Therefore, it is recommended that x = -3 to -1 mm.

Claims

1. An epitaxial device, characterized in that, The device includes a quartz air inlet square tube, an induction coil, an upper half-moon heating seat, a lower half-moon heating seat, an upstream insulation cover, and a downstream insulation cover. The upper and lower half-moon heating seats are symmetrically arranged. The upstream and downstream insulation covers are located at both ends of the upper and lower half-moon heating seats. Both the upper and lower half-moon heating seats are hollow half-moon structures with openings at both ends, including an arc surface and a flat surface. The two sides of the flat surfaces of the upper and lower half-moon heating seats are connected by insulating components. The flat surfaces of the upper and lower half-moon heating seats and the upstream ends of the two insulating components extend outward and pass through a through hole in the middle of the upstream insulation cover to connect with the quartz air inlet square tube. The upper half-moon heating seat, lower half-moon heating seat, upstream insulation cover, and downstream insulation cover are all located inside the induction coil, while the quartz air inlet square tube is located outside the induction coil.

2. The epitaxial device according to claim 1, characterized in that, The upper and lower half-moon heating bases each include a heating section and an extension section on their planes. The heating section is connected to the arc surface. The extension section passes through the through hole in the middle of the upstream insulation cover. The thickness of the extension section is the same as the wall thickness of the upper and lower walls of the quartz air inlet square tube. The size of the air inlet channel formed between the extension sections of the upper and lower half-moon heating bases is the same as the size of the air inlet channel of the quartz air inlet square tube.

3. The epitaxial device according to claim 2, characterized in that, The insulating component includes a base and an extension. The base of the insulating component is connected to the heating portion of the upper and lower half-moon heating seats. The extension of the insulating component is connected to the extension portion of the upper and lower half-moon heating seats. The left and right walls of the quartz air inlet square tube of the extension of the insulating component have the same wall thickness. The size of the air inlet channel formed between the two extensions of the insulating component is the same as the size of the air inlet channel of the quartz air inlet square tube.

4. The epitaxial device according to claim 1, characterized in that, The quartz air inlet square tube is equipped with two horizontal baffles and two vertical baffles. The two horizontal baffles are arranged parallel to each other vertically, and the two vertical baffles are perpendicular to the horizontal baffles and arranged parallel to each other. The two vertical baffles divide the quartz air inlet tube into a first side air inlet channel, a horizontal middle air inlet channel and a second side air inlet channel in the horizontal direction. The two horizontal baffles divide the first side air inlet channel, the horizontal middle air inlet channel and the second side air inlet channel of the quartz air inlet tube into an upper air inlet channel, a vertical middle air inlet channel and a lower air inlet channel in the vertical direction. The upper air inlet channel is used to introduce carrier gas, and the middle air inlet channel and the lower air inlet channel are used to introduce special gas.

5. The epitaxial device according to claim 4, characterized in that, The height of the upper air intake channel is greater than that of the middle air intake channel, and the height of the middle air intake channel is greater than that of the lower air intake channel.

6. The epitaxial device according to claim 5, characterized in that, The height difference between the middle air intake channel and the upper air intake channel is the same as the height difference between the lower air intake channel and the middle air intake channel.

7. The epitaxial device according to claim 6, characterized in that, The height difference between the middle and upper air intake channels and between the lower and middle air intake channels ranges from 1 to 3 mm.

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