An anti-backflow gas transport device and method for vapor phase epitaxial growth

Abstract

The present invention provides an anti-backflow gas transport device and method for vapor phase epitaxial growth. The device has a nozzle structure and at least includes a multi-channel pipeline inlet, a multi-channel gas transport pipeline, a multi-channel pipeline outlet, a nozzle multi-channel pipeline outlet, an internal reaction chamber, and multiple variable-diameter anti-backflow plates. By arranging anti-backflow plates at the multi-channel pipeline outlet to form a funnel-like structure, it is possible to avoid the phenomenon that the outlet of the gas outlet pipe is affected by the surrounding gas to form turbulence and even cause fluid backflow due to the small cross-sectional area, large flow rate, and small pressure of the multi-channel pipeline outlet. The present invention avoids the siphon backflow phenomenon at the nozzle due to the too large flow rate of a single pipeline outlet by regulating the pressure difference of the nozzle multi-channel pipeline outlet. By regulating the laminar flow transport of the gas, the particles generated by pre-reaction can be effectively reduced, thereby improving the crystal quality. The structure of the present invention is simple, easy to manufacture, and has strong practicability, and has extremely high commercial value.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor vapor phase epitaxial growth and flow field control, and particularly to an anti-backflow gas transport device and method for vapor phase epitaxial growth. Background Art

[0002] The research and application of group III-V semiconductor materials are the forefront and hotspots of global semiconductor research. In the process of semiconductor wafer growth and vapor phase epitaxy, controlling gas convection fields and reducing pre-reactions are key factors for high-quality semiconductor growth and epitaxy.

[0003] Currently, most mainstream commercial semiconductor devices on the market, such as metal-organic chemical vapor deposition systems (MOCVD), adopt a vertical reaction chamber design. This design can well ensure the uniformity and reliability of thin film deposition, but the growth rate of such devices is slow and they can only be used for growing thin films. Another commercial semiconductor device, such as a hydride vapor phase epitaxy system (HVPE), transports the group III and group V source gases required for deposition into the reaction chamber through a nozzle above the reaction chamber, and diffuses them to the substrate surface, where nucleation occurs on the substrate surface and thick film growth takes place. The by-products of the reaction and some unreacted gases are then evacuated from the reaction chamber by a vacuum pump. Such devices have a high growth rate and high productivity, which is beneficial for cost reduction. However, the gas nozzles of such devices are far from the substrate, the gas diffusion distance is long, and pre-reactions are likely to occur, resulting in polycrystals that affect crystal growth. Although the pre-reaction can be reduced by adding a shielding gas between the two reaction gases, its process regulation requirements are high, and there are also problems such as turbulence and backflow caused by mismatched convection fields. Patent CN209039581U proposes a quartz flow equalizing plate. This flow equalizing structure can make the gas flow in evenly to a certain extent, but it is relatively difficult to process it into the gas transport pipeline in the nozzle, and the gas flow rate is still large at the position close to the air inlet, failing to achieve the ideal completely uniform inflow effect and unable to ensure laminar flow of the gas. Summary of the Invention

[0004] Aiming at the deficiencies in the prior art, the purpose of the present invention is to provide an anti-backflow gas transport device and method for vapor phase epitaxial growth, which are used to prevent backflow during gas transport and flow field regulation, thereby ensuring the laminar distribution of the flow field and improving the uniformity of crystal growth.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] First, the present invention provides an anti-backflow gas transport device for vapor phase epitaxial growth, comprising:

[0007] The Ga path pipeline, the Ga path pipeline includes a Ga path pipeline air inlet, a Ga path gas transport pipeline, and a Ga path pipeline air outlet, and a first variable-diameter anti-backflow plate is provided at the Ga path pipeline air outlet;

[0008] The ID path pipeline, the ID path pipeline includes an ID path pipeline air inlet, an ID path gas transport pipeline, and an ID path pipeline air outlet, and a second variable-diameter anti-backflow plate is provided at the ID path pipeline air outlet;

[0009] The NH3 path pipeline, the NH3 path pipeline includes an NH3 path pipeline air inlet, an NH3 path gas transport pipeline, and an NH3 path pipeline air outlet, and a third variable-diameter anti-backflow plate is provided at the NH3 path pipeline air outlet;

[0010] And an internal reaction chamber.

[0011] Furthermore, the first variable-diameter anti-backflow plate is of a funnel-like structure, and the cross-sectional area ratio of the Ga path pipeline air inlet to the Ga path pipeline air outlet is 1:3 to 10.

[0012] Furthermore, the second variable-diameter anti-backflow plate is of a funnel-like structure, and the cross-sectional area ratio of the ID path pipeline air inlet to the ID path pipeline air outlet is 1:5 to 20.

[0013] Furthermore, the third variable-diameter anti-backflow plate is of a funnel-like structure, and the cross-sectional area ratio of the NH3 path pipeline air inlet to the NH3 path pipeline air outlet is 1:3 to 10.

[0014] Furthermore, the Ga path pipeline is further provided with a nozzle at the Ga path pipeline air outlet, the ID path pipeline is further provided with a nozzle at the ID path pipeline air outlet, and the NH3 path pipeline is further provided with a nozzle at the NH3 path pipeline air outlet.

[0015] Second, the present invention provides an anti-backflow gas transport method for vapor phase epitaxial growth. The gas passes through the above-mentioned anti-backflow gas transport device for vapor phase epitaxial growth, and cooperatively adjusts the volume flow rate and area of the air outlets of multiple pipelines in the anti-backflow gas transport device, and controls the pressure difference of the air outlets of the nozzle multiple pipelines to avoid the formation of turbulence and even backflow.

[0016] Furthermore, the cross-sectional area ratio of the Ga path pipeline air outlet, the ID path pipeline air outlet, and the NH3 path pipeline air outlet is 1:2 to 8:1 to 3.

[0017] Furthermore, the inlet gas volume flow rate ratio of the Ga path pipeline, the ID path pipeline, and the NH3 path pipeline is 1:3 to 10:1 to 5.

[0018] Furthermore, the pressure ratio of the Ga path pipeline air outlet, the ID path pipeline air outlet, and the NH3 path pipeline air outlet is 1:1.2 to 1.3:1.1 to 1.2.

[0019] The beneficial effects of the present invention are as follows:

[0020] The device of the present invention is used to prevent backflow during gas transportation and flow field regulation, thereby ensuring the laminar flow distribution of the flow field and improving the uniformity of crystal growth.

[0021] The device of the present invention has a nozzle structure, including a multi-channel pipeline inlet, multi-channel gas transportation pipelines, multi-channel pipeline outlets, nozzle multi-channel pipeline outlets, an internal reaction chamber, and multiple variable-diameter anti-backflow plates. By setting anti-backflow plates at the multi-channel pipeline outlets, a funnel-like structure is formed to avoid the formation of turbulence and even fluid backflow at the outlet pipe due to the small cross-sectional area, high flow rate, and low pressure at the multi-channel pipeline outlets, which are affected by the surrounding gas.

[0022] The present invention avoids the siphon backflow phenomenon at the nozzle due to the excessive flow rate of a single pipeline outlet by regulating the pressure difference at the nozzle multi-channel pipeline outlets. By regulating the laminar flow transportation of the gas flow, the particles generated by the pre-reaction can be effectively reduced, thereby improving the crystal quality. The structure of the present invention is simple, easy to manufacture, and has strong practicability, with extremely high commercial value. Description of the Drawings

[0023] Figure 1 Schematic cross-sectional structure diagram of the device of the present invention;

[0024] Figure 2 Schematic cross-sectional structure diagram of the device of Comparative Example 1;

[0025] Figure 3 Schematic cross-sectional structure diagram of the device of Comparative Example 2;

[0026] Figure 4 Schematic diagram of the gas flow at the ID-channel pipeline outlet of the device of the present invention;

[0027] Figure 5 Schematic diagram of the gas flow at the ID-channel pipeline outlet in the prior art;

[0028] Figure 6 Microscope picture of the uniform and high-quality growth of the substrate;

[0029] Figure 7 Microscope picture of polycrystalline falling on the substrate.

[0030] Reference Signs:

[0031] 11 - Inlet of Ga-channel pipeline, 12 - Inlet of ID-channel pipeline, 13 - Inlet of NH3-channel pipeline;

[0032] 21 - Outlet of Ga-channel pipeline, 22 - Outlet of ID-channel pipeline, 23 - Outlet of NH3-channel pipeline;

[0033] 31-Ga gas transport pipeline, 32-ID gas transport pipeline, 33-NH3 gas transport pipeline; 40-Inner reaction chamber;

[0034] 210-First variable-diameter anti-backflow plate, 220-Second variable-diameter anti-backflow plate, 230-Third variable-diameter anti-backflow plate; 51-Ga pipeline gas outlet of the nozzle, 52-ID pipeline gas outlet of the nozzle, 53-NH3 pipeline gas outlet of the nozzle. Detailed implementation mode

[0035] To further understand the present invention, the preferred implementation modes of the present invention are described below in conjunction with embodiments. However, it should be understood that these descriptions are only for further explaining the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0036] The anti-backflow gas transport device for vapor phase epitaxial growth of the present invention includes three-way pipeline inlets, three-way gas transport pipelines, three-way pipeline outlets, three-way pipeline outlets of the nozzle, an inner reaction chamber 40, and three anti-backflow plates. The present invention avoids the siphon phenomenon caused by the excessive flow rate of a single pipeline outlet at the nozzle, and further leads to the formation of turbulence and even backflow by coordinately regulating the nozzle area and the inlet gas volume flow rate, and then regulating the pressure difference at the three-way pipeline outlets. Regulating the laminar flow transport of the gas can effectively reduce the particles generated by pre-reaction, and then improve the crystal quality.

[0037] As Figure 1 shown, in this embodiment, the Ga pipeline includes a Ga pipeline inlet 11, a Ga gas transport pipeline 31, and a Ga pipeline outlet 21. A first variable-diameter anti-backflow plate 210 is provided at the Ga pipeline outlet; the ID pipeline includes an ID pipeline inlet 12, an ID gas transport pipeline 32, and an ID pipeline outlet 22. A second variable-diameter anti-backflow plate 220 is provided at the ID pipeline outlet; the NH3 pipeline includes an NH3 pipeline inlet 13, an NH3 gas transport pipeline 33, and an NH3 pipeline outlet 23. A third variable-diameter anti-backflow plate 230 is provided at the NH3 pipeline outlet. The Ga pipeline is also provided with a Ga pipeline gas outlet 51 of the nozzle, the ID pipeline is also provided with an ID pipeline gas outlet 52 of the nozzle, and the NH3 pipeline is also provided with an NH3 pipeline gas outlet 53 of the nozzle.

[0038] It is well known that

[0039] The Bernoulli equation is: P + ρ*u 2 / 2 + ρgh = constant (P0) (Formula 1);

[0040] For gases, the gravity can be ignored. Therefore, the Bernoulli equation can be simplified to: P + ρ*u 2 / 2 = constant (P0) (Formula 2);

[0041] Wherein, P is the static pressure, ρ*u 2 / 2 is the dynamic pressure, the constant (P0) is the total pressure, ρ is the gas density, and u is the gas flow velocity; also, u = q v / A, where q v is the volumetric flow rate and A is the cross-sectional area of the pipeline.

[0042] Therefore, P = P0 - ρ*u 2 / 2 = P0 - ρ*(q v / A) 2 / 2 (Formula 3);

[0043] It can be seen from Formula 3 that when the cross-sectional area is small, the flow velocity is fast and the pressure is small; when the cross-sectional area is large, the flow velocity is slow and the pressure is large.

[0044] As Figure 1 shown, in this embodiment, the Ga gas enters the internal reaction chamber 40 through the Ga gas pipeline inlet 11 and the Ga gas pipeline outlet 21 and reacts with the gallium liquid therein to generate GaCl gas, and then is transported to the substrate surface through the Ga gas transport pipeline 31 and the nozzle Ga gas pipeline outlet 51 to react with ammonia. The first variable-diameter anti-backflow plate 210 at the Ga gas pipeline outlet 21 forms a structure similar to an inverted funnel. Optionally, the ratio of the cross-sectional area of the Ga gas pipeline inlet 11 to the cross-sectional area of the Ga gas pipeline outlet 21 is 1:3 to 10. It can be seen from Formula 3 that when the cross-sectional area increases, the flow velocity slows down and the pressure increases, so that the HCl gas in the Ga inlet can fully react with the gallium liquid and prevent it from being sucked back into the inlet pipe. The ID gas is transported to the substrate surface through the ID gas pipeline inlet 12, the ID gas pipeline outlet 22, the ID gas transport pipeline 32 and the nozzle ID gas pipeline outlet 52, and its main function is to isolate GaCl and NH3 and delay their reaction. Similarly, as the cross-sectional area gradually increases, the pressure also gradually increases, which can make the ID gas enter the ID gas transport pipeline 32 in a laminar flow. Optionally, the ratio of the cross-sectional area of the ID gas pipeline inlet 12 to the cross-sectional area of the ID gas pipeline outlet 22 is 1:5 to 20. The NH3 gas is transported to the substrate surface through the NH3 gas pipeline inlet 13, the NH3 gas pipeline outlet 23, the NH3 gas transport pipeline 33 and the nozzle NH3 gas pipeline outlet 53 to react with GaCl. Similarly, increasing the cross-sectional area can promote the laminar flow transport of the NH3 gas. Optionally, the ratio of the cross-sectional area of the NH3 gas pipeline inlet 13 to the cross-sectional area of the NH3 gas pipeline outlet 23 is 1:3 to 10.

[0045] In addition, it can be seen from Equation 3 that the pressure at the gas outlets of the three pipelines of the nozzle structure depends on the ratio of the volume flow rate of the gas inlet of the three pipelines to the cross-sectional area of the gas outlets of the three pipelines of the nozzle structure. Optionally, controlling the pressure ratio of the gas outlets of the three pipelines of the nozzle structure to be 1:1.2-1.3:1.1-1.2 can avoid the occurrence of turbulence or siphon phenomenon due to excessive pressure difference at the gas outlets. Optionally, the cross-sectional area ratio of the gas outlets of the three pipelines of the nozzle structure is 1:2-8:1-3, and the volume flow rate ratio of the gas outlets of the three pipelines of the nozzle structure is 1:3-10:1-5.

[0046] As Figure 1 shown, in this embodiment, the volume flow rate ratio of the gas outlets of the three pipelines of the nozzle structure is 1:3:2, and the cross-sectional area of the gas outlets of the three pipelines of the nozzle structure is adjusted so that the pressure ratio of the gas outlets of the three pipelines of the nozzle is 1:1.3:1.2. As Figure 6 shown, it is found through simulation that the laminar flow of the gas outlets of the three pipelines of the nozzle is transported to the substrate surface, and no obvious polycrystalline drops are found on the substrate in the experiment.

[0047] As Figure 1 shown, in other embodiments, the cross-sectional area ratio of the gas outlets of the three pipelines of the nozzle structure is 1:3:2, and the volume flow rate of the gas inlet of the three pipelines of the nozzle structure is adjusted so that the pressure ratio of the gas outlets of the three pipelines of the nozzle is 1:0.5:1. As Figure 7 shown, it is found that a significant siphon phenomenon occurs below the gas outlet of the nozzle pipeline, causing GaCl and NH3 to react in advance to produce polycrystals.

[0048] As Figure 2 shown, in a comparative example, the second variable-diameter anti-backflow plate type funnel structure in Figure 1 is not adopted at the gas outlet 22 of the ID pipeline. The cross-sectional area ratio of the gas outlet to the gas inlet of the ID pipeline is 20:1. According to Equation 3, the pressure at the gas outlet decreases significantly, while the pressure of the gas transport pipeline of the ID pipeline is relatively large, forming a large pressure difference, and thus a turbulence phenomenon occurs. This may cause the gas of the ID pipeline to lose its isolation effect, causing the GaCl and NH3 gases to siphon into the ID pipeline and react in advance, ultimately resulting in gallium nitride polycrystals falling on the substrate and affecting the crystal quality of the substrate. The third variable-diameter anti-backflow plate type funnel structure in Figure 1 is not adopted at the gas outlet 23 of the NH3 pipeline. The cross-sectional area ratio of the gas outlet to the gas inlet of the NH3 pipeline is 10:1, which is similar to the situation of the gas outlet of the ID pipeline in Figure 2 . The cross-sectional area suddenly increases, forming a large pressure difference, which also leads to turbulent gas transport. At the same time, since the gas outlet of the NH3 pipeline is close to the gas outlet of the NH3 pipeline of the nozzle structure, its turbulence phenomenon will also have a greater impact on the gas outlet of the nozzle pipeline.

[0049] As Figure 3 shown, the gas outlet 22 of the ID pipeline andFigure 2 If the same non-reducing-diameter anti-backflow plate 2-type funnel structure is not adopted, and at the same time the nozzle structure has the Ga gas outlet pipe and the NH3 gas outlet pipe not on the same horizontal plane, it will cause the GaCl and NH3 gases to be siphoned to the inner side of the ID pipeline, resulting in the parasitic phenomenon of gallium nitride polycrystals, and the gallium nitride polycrystals will fall off irregularly, affecting the crystal quality.

[0050] According to the disclosure of the above specification, those skilled in the art to which the present invention pertains can also make appropriate changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present invention.

Claims

1. An anti-backflow gas transport device for vapor phase epitaxial growth, characterized in that: Comprising: The Ga path pipeline, the Ga path pipeline includes a Ga path pipeline inlet, a Ga path gas transport pipeline, and a Ga path pipeline outlet, and a first variable-diameter anti-backflow plate is provided at the Ga path pipeline outlet; the first variable-diameter anti-backflow plate is of a funnel-like structure, and the cross-sectional area ratio of the Ga path pipeline inlet to the Ga path pipeline outlet is 1:3 to 10; The ID path pipeline, the ID path pipeline includes an ID path pipeline inlet, an ID path gas transport pipeline, and an ID path pipeline outlet, and a second variable-diameter anti-backflow plate is provided at the ID path pipeline outlet; the second variable-diameter anti-backflow plate is of a funnel-like structure, and the cross-sectional area ratio of the ID path pipeline inlet to the ID path pipeline outlet is 1:5 to 20; The NH3 path pipeline, the NH3 path pipeline includes an NH3 path pipeline inlet, an NH3 path gas transport pipeline, and an NH3 path pipeline outlet, and a third variable-diameter anti-backflow plate is provided at the NH3 path pipeline outlet; the third variable-diameter anti-backflow plate is of a funnel-like structure, and the cross-sectional area ratio of the NH3 path pipeline inlet to the NH3 path pipeline outlet is 1:3 to 10; And an internal reaction chamber.

2. The anti-backflow gas transport device for vapor phase epitaxial growth according to claim 1, characterized in that: The Ga path pipeline is further provided with a nozzle at the Ga path pipeline outlet, The ID path pipeline is further provided with a nozzle at the ID path pipeline outlet, The NH3 path pipeline is further provided with a nozzle at the NH3 path pipeline outlet.

3. A method for anti-backflow gas transport in vapor phase epitaxial growth, characterized in that, The gas passes through the anti-backflow gas transport device for vapor phase epitaxial growth according to claim 1 or 2, and cooperatively adjusts the volume flow rate and area of the outlets of multiple pipelines in the anti-backflow gas transport device to control the pressure difference at the outlets of multiple pipelines of the nozzle, so as to avoid the formation of turbulence and even backflow.

4. The anti-backflow gas transport method for vapor phase epitaxial growth according to claim 3, characterized in that: The cross-sectional area ratio of the Ga path pipeline outlet, the ID path pipeline outlet, and the NH3 path pipeline outlet is 1:2 to 8:1 to 3.

5. The anti-backflow gas transport method for vapor phase epitaxial growth according to claim 3, characterized in that: The inlet gas volume flow rate ratio of the Ga path pipeline, the ID path pipeline, and the NH3 path pipeline is 1:3 to 10:1 to 5.

6. The anti-backflow gas transport method for vapor phase epitaxial growth according to claim 3, wherein: The pressure ratio of the Ga path pipeline outlet, the ID path pipeline outlet, and the NH3 path pipeline outlet is 1:1.2 to 1.3:1.1 to 1.2.

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