A chemical vapor deposition device and method for preparing particle products

Abstract

The present invention discloses a chemical vapor deposition device for preparing particle products, wherein a cylinder is vertically arranged in the inner cavity of a chemical vapor deposition furnace, the upper end of the cylinder abuts against the upper cover, and the lower end abuts against the lower cover; at least three supporting rings are arranged on the inner wall of the cylinder; at least three porous plates are arranged in the cylinder; the porous plates have a plurality of through holes, and the edges of the porous plates are placed on the supporting rings; a plurality of nozzles are arranged between two adjacent porous plates, a plurality of perforations are arranged on the side walls of the nozzles, the lower end of the nozzle abuts against the porous plate below, and the upper end of the nozzle abuts against the porous plate above; the through holes of the porous plate below all correspond to the inner cavities of the plurality of nozzles, and the through holes of the porous plate above all correspond to the gaps between the plurality of nozzles. The present invention guides and controls the flow path of the reaction gas, thereby realizing the growth of high-purity silicon carbide powder in the raw material atmosphere through chemical vapor deposition, and can realize the preparation of large-particle-size, high-purity particles.

Description

Technical Field

[0001] The invention relates to a chemical vapor deposition device and a method for preparing a particle product, belonging to the technical field of chemical vapor deposition. Background Art

[0002] Single crystal silicon carbide is a third-generation compound semiconductor material with excellent characteristics such as wide band gap, high thermal conductivity, high critical breakdown electric field, high carrier saturation drift velocity and good chemical stability. It is suitable for manufacturing high-temperature, high-frequency, high-power, radiation-resistant and corrosion-resistant electronic devices and has broad application prospects. At present, with the continuous deepening and expansion of research and application of silicon carbide devices in the fields of power electronics, radio frequency devices, optoelectronic devices, etc., the corresponding quality requirements for the purity of silicon carbide materials are also constantly increasing, especially for the silicon carbide raw material powder used in the growth of single crystal silicon carbide.

[0003] At present, there are three main methods for synthesizing SiC powder: Acheson method, organic synthesis method and self-propagating method. In Acheson method, SiO2 is reduced by C to generate β-SiC under high temperature and strong electric field, and then transformed into α-SiC under high temperature, and then through crushing, pickling and other processes. The silicon carbide powder prepared by this method has a high impurity content and its purity cannot be used for the growth of semiconductor single crystals.

[0004] The organic synthesis method is mainly used to prepare nano-scale SiC powder. Generally, there are a variety of impurity elements in the raw materials for synthesis. Although high-purity SiC powder with very high purity can be obtained through subsequent treatment, the subsequent treatment process is complicated and the collection of micro-powder is difficult. It is not suitable for mass production and use, and it is easy to produce substances harmful to the human body. In addition, the particle size of the SiC powder synthesized by this method is too small, which will seriously affect the crystallization quality of the SiC single crystal.

[0005] The self-propagating method (solid phase synthesis) is the main process for preparing semi-insulating SiC single crystal materials at home and abroad. This method uses high-purity carbon powder and high-purity silicon powder as starting materials, and obtains SiC polycrystalline source powder through solid phase sintering process, which can basically meet the needs of growing SiC single crystals. There are two main problems with this method: 1. The raw materials are all high-purity materials, and they are high-purity powder materials, which are relatively expensive; 2. The synthesized raw materials need to be crushed, which is easy to introduce impurities, and during the synthesis process, it is inevitable to introduce impurities due to factors such as high temperature and atmosphere environment, especially nitrogen elements cannot be avoided, which affects the quality and stability of semi-insulating SiC single crystals.

[0006] In summary, the main technical problems existing in the existing methods and equipment for preparing SiC powder (particles) are: (1) the purity of the synthesized silicon carbide powder cannot be guaranteed; (2) the single furnace production capacity is low and the product cost is high; (3) the particle size of the product particles is small. Summary of the invention

[0007] In order to overcome the problems existing in the prior art, the present invention provides a chemical vapor deposition device and method for preparing a particle product, and the specific technical solution is as follows.

[0008] A chemical vapor deposition device for preparing a particle product, comprising a chemical vapor deposition furnace, the chemical vapor deposition furnace comprising an upper cover and a lower cover, the lower cover being provided with an air inlet channel, the upper cover being provided with an air outlet channel, characterized in that it also comprises a barrel, a porous plate and a nozzle;

[0009] The cylinder is vertically arranged in the inner cavity of the chemical vapor deposition furnace, the upper end of the cylinder abuts against the upper cover, and the lower end abuts against the lower cover; at least three supporting rings are arranged on the inner wall of the cylinder;

[0010] At least three porous plates are arranged in the cylinder at intervals along the vertical direction, and there is a gap between the lowest porous plate and the lower cover;

[0011] The porous plate has a plurality of through holes, and the edge of the porous plate is placed on the supporting ring; a plurality of nozzles are arranged between two adjacent porous plates, and a plurality of through holes are arranged on the side wall of the nozzle; the nozzle is arranged vertically, and the lower end of the nozzle abuts against the porous plate below, and the upper end of the nozzle abuts against the porous plate above; the through holes of the porous plate below all correspond to the inner cavities of the plurality of nozzles, and the through holes of the porous plate above all correspond to the gaps between the plurality of nozzles.

[0012] By adopting the above technical scheme, the reaction gas of the chemical vapor deposition furnace enters from the lower cover into the gap between the lowest (first layer) porous plate and the lower cover, and then the reaction gas enters into the nozzle above the first layer of porous plate through the through hole of the lowest porous plate, and enters into between the first layer of porous plate and the second layer of porous plate through the perforation of the nozzle; high-purity silicon carbide powder is placed on the first layer of porous plate, and the high-purity silicon carbide powder is in a moving (floating) state under the blowing of the reaction gas. The high-purity silicon carbide powder continuously deposits silicon carbide under the action of the reaction gas, so that the high-purity silicon carbide powder The particle size continues to increase; part of the reaction gas will enter the nozzle above the second porous plate through the through holes of the second porous plate, and then enter between the second porous plate and the third porous plate, high-purity silicon carbide powder is also placed on the second porous plate, and the high-purity silicon carbide powder will also continue to grow through chemical vapor deposition, and so on. Several layers of porous plates can be set to fully utilize the reaction gas, wherein there is a gap between the uppermost porous plate and the upper cover, and no high-purity silicon carbide powder is placed on the uppermost porous plate, and no nozzle is placed.

[0013] Furthermore, the cylinder, the porous plate and the nozzle are all made of graphite. Graphite has good high temperature stability and is very suitable for use in a chemical vapor deposition furnace.

[0014] Furthermore, the cylinder includes a plurality of section cylinder modules, and the plurality of section cylinder modules are stacked in the vertical direction, and each section cylinder module is provided with the support ring. Preferably, the upper end face of the lower cylinder module has a circular protrusion or a circular groove, and the lower end face of the upper cylinder module has a circular groove or a circular protrusion. Arranging the cylinder to include a plurality of section cylinder modules is conducive to the installation and disassembly of each layer of the porous plate and the nozzle. At the same time, by arranging the circular groove or the circular protrusion on the end face of the cylinder module, it is conducive to improving the connection positioning accuracy of the two adjacent section cylinder modules and the sealing performance of the connection. Improving the sealing performance of the connection is conducive to keeping the reaction gas inside the cylinder as much as possible, reducing the chemical deposition on the inner wall of the chemical vapor deposition furnace, which is not only conducive to improving the service life of the chemical vapor deposition furnace, but also conducive to improving the utilization rate of the reaction gas.

[0015] Furthermore, the cylinder includes a plurality of connecting rings and a plurality of cylinder modules, and two adjacent cylinder modules in the vertical direction are connected by the connecting rings; the supporting rings are arranged on the connecting rings or the cylinder modules. Preferably, the upper and lower end faces of the cylinder modules both have annular protrusions or annular grooves, and the upper and lower end faces of the connecting rings both have annular grooves or annular protrusions. By providing the connecting rings, it is helpful to reduce the manufacturing difficulty and maintenance cost of the entire cylinder.

[0016] Furthermore, the diameter of the lower nozzle is larger than the diameter of the upper nozzle, and the diameter of the through hole of the lower nozzle is larger than the diameter of the through hole of the upper nozzle.

[0017] Based on the same inventive concept, the present invention also relates to a method for preparing a particle product, which uses the above-mentioned chemical vapor deposition device, characterized in that:

[0018] Except for the uppermost porous plate, the remaining porous plates are all placed with granular products; after completing one chemical vapor deposition, before the next chemical vapor deposition, at least part of the granular products on the upper porous plate are placed on the lower porous plate for the next chemical vapor deposition. It should be noted that the upper porous plate here refers to the porous plates except the lowermost porous plate, and the lower porous plate here refers to any one or more porous plates below the previous specific porous plate.

[0019] Preferably, the particle product is silicon carbide particles.

[0020] Compared with the prior art, the present invention has the following beneficial effects.

[0021] 1. By guiding and controlling the flow path of the reaction gas, high-purity silicon carbide powder (particles) can be grown by chemical vapor deposition in the raw material atmosphere, and the preparation of large-size and high-purity powder (particles) can be achieved;

[0022] 2. The powder growth reaction chamber is divided vertically to achieve efficient conversion of raw gas and improve material utilization;

[0023] 3. The raw gas reacts continuously during the bottom-up transportation process, so that powders of different particle sizes are deposited in different areas. The particle size of the product powder in the top deposition chamber is the smallest, which can be used as the seed powder for the next batch and the next chamber, and is continuously recycled in actual production and eventually grows into products.

[0024] 4. The invention adopts a relatively low synthesis temperature, which can realize batch preparation, improve production efficiency and reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a perspective view of the appearance of the chemical vapor deposition device of the present invention;

[0026] Figure 2 is a cross-sectional schematic diagram of a chemical vapor deposition apparatus of the present invention (front view);

[0027] Figure 3 is a cross-sectional schematic diagram of a chemical vapor deposition apparatus of the present invention (oblique top view);

[0028] Figure 4 is a cross-sectional schematic diagram of a chemical vapor deposition apparatus of the present invention (obliquely viewed from above);

[0029] Figure 5 is a cross-sectional schematic diagram of the connecting ring;

[0030] Figure 6 It is a schematic diagram of the connection relationship between the cylinder module, the connecting ring and the porous plate.

[0031] In the figure: chemical vapor deposition furnace 1, cylinder 2, porous plate 3, nozzle 4, upper cover 1.1, lower cover 1.2, air inlet channel 1.3, air outlet channel 1.4, supporting ring 2.1, cylinder module 2.2, ring protrusion 2.3, ring groove 2.4, connecting ring 2.5, through hole 3.1, through hole 4.1. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0033] See also Figure 1-Figure 4A chemical vapor deposition device for preparing a particle product, comprising a chemical vapor deposition furnace 1, the chemical vapor deposition furnace 1 comprising an upper cover 1.1 and a lower cover 1.2, the lower cover 1.2 being provided with an air inlet channel 1.3, the upper cover 1.1 being provided with an air outlet channel 1.4; and further comprising a barrel 2, a porous plate 3 and a nozzle 4;

[0034] The cylinder 2 is vertically arranged in the inner cavity of the chemical vapor deposition furnace 1, the upper end of the cylinder 2 abuts against the upper cover 1.1, and the lower end abuts against the lower cover 1.2; four supporting rings 2.1 are arranged on the inner wall of the cylinder 2;

[0035] Four porous plates 3 are arranged in the cylinder 2 at intervals along the vertical direction, and there is a gap between the lowest (lowest layer) porous plate 3 and the lower cover 1.2;

[0036] The porous plate 3 has a plurality of through holes 3.1, and the edge of the porous plate 3 is placed on the supporting ring 2.1; a plurality of nozzles 4 are arranged between two adjacent porous plates 3, and a plurality of perforations 4.1 are arranged on the side wall of the nozzle 4, and the nozzle 4 is arranged vertically, and the lower end of the nozzle 4 abuts against the porous plate 3 below, and the upper end of the nozzle 4 abuts against the porous plate 3 above; the through holes 3.1 of the porous plate 3 below all correspond to the inner cavities of the plurality of nozzles 4, and the through holes 3.1 of the porous plate 3 above all correspond to the gaps between the plurality of nozzles 4. Among them, the through holes 3.1 are evenly distributed on the porous plate 3 to ensure the uniformity of the distribution of the reaction gas; the perforations 4.1 also need to be evenly distributed on the nozzle 4.

[0037] The barrel 2 , the porous plate 3 and the nozzle 4 are all made of graphite. Graphite has good high temperature stability and is very suitable for use in the chemical vapor deposition furnace 1 .

[0038] Wherein, the cylinder 2 includes a plurality of cylinder modules 2.2, and the plurality of cylinder modules 2.2 are stacked in the vertical direction, and each cylinder module 2.2 is provided with a supporting ring 2.1. Preferably, the upper end surface of the lower cylinder module 2.2 has a circular protrusion 2.3 or a circular groove 2.4, and the lower end surface of the upper cylinder module 2.2 has a circular groove 2.4 or a circular protrusion 2.3. The cylinder 2 is configured to include a plurality of cylinder modules 2.2, which is conducive to the installation and removal of the porous plate 3 and the nozzle 4 of each layer. At the same time, by providing the circular groove 2.4 or the circular protrusion 2.3 on the end surface of the cylinder module 2.2, it is conducive to improving the connection positioning accuracy of the two adjacent cylinder modules 2.2 and the sealing performance of the connection. Improving the sealing performance of the connection is conducive to keeping the reaction gas inside the cylinder 2 as much as possible, reducing the chemical deposition on the inner wall of the chemical vapor deposition furnace 1, which is not only conducive to improving the service life of the chemical vapor deposition furnace 1, but also conducive to improving the utilization rate of the reaction gas.

[0039] The connection method between the top barrel module 2.2 and the upper cover, and the connection method between the bottom barrel module 2.2 and the lower cover are similar to the connection method between two adjacent barrel modules 2.2, using the matching method of the annular groove 2.4 and the annular protrusion 2.3.

[0040] like Figure 5-Figure 6 As shown, in another embodiment, the cylinder 2 includes a plurality of connecting rings 2.5 and a plurality of cylinder modules 2.2, and two adjacent cylinder modules 2.2 in the vertical direction are connected by the connecting ring 2.5; a supporting ring 2.1 is provided on the connecting ring 2.5. Preferably, the upper and lower end surfaces of the cylinder module 2.2 both have an annular protrusion 2.3, and the upper and lower end surfaces of the connecting ring 2.5 both have an annular groove 2.4. By setting the connecting ring 2.5 and setting the supporting ring 2.1 on the connecting ring 2.5, it is not only convenient to disassemble and assemble the porous plate 3 and the nozzle 4, but also greatly reduces the manufacturing difficulty of the entire cylinder 2. The supporting ring 2.1 is a vulnerable part. If the supporting ring 2.1 is set on the cylinder module 2.2, once the supporting ring 2.1 is damaged, the entire cylinder module 2.2 cannot be used. If the supporting ring 2.1 is set on the connecting ring 2.5, if the supporting ring 2.1 is damaged, only the single connecting ring 2.5 needs to be replaced, which greatly reduces the manufacturing difficulty and maintenance cost of the entire cylinder 2.

[0041] In a preferred embodiment, the diameter of the through hole 3.1 of the lower porous plate 3 is larger than the diameter of the through hole 3.1 of the upper porous plate 3; the diameter of the lower nozzle 4 is larger than the diameter of the upper nozzle 4, and the diameter of the through hole 4.1 of the lower nozzle 4 is larger than the diameter of the through hole 4.1 of the upper nozzle 4. By adjusting the nozzle diameter and the through hole diameter, the raw material conversion rate can be effectively improved.

[0042] The working principle of the present invention is as follows: the reaction gas of the chemical vapor deposition furnace 1 enters into the gap between the bottom (first layer) porous plate 3 and the bottom cover 1.2 from the air inlet channel 1.3 of the bottom cover 1.2, and then the reaction gas enters into the nozzle 4 above the first layer porous plate 3 through the through hole 3.1 of the bottom porous plate 3, and enters into between the first layer porous plate 3 and the second layer porous plate 3 through the perforation 4.1 of the nozzle 4; high-purity silicon carbide powder is placed on the first layer porous plate 3, and the high-purity silicon carbide powder is in a moving (floating) state under the blowing of the reaction gas, and the high-purity silicon carbide powder continuously deposits silicon carbide under the action of the reaction gas, so that the high-purity silicon carbide The particle size of silicon carbide powder continues to increase; part of the reaction gas will enter the nozzle 4 above the second porous plate 3 through the through hole 3.1 of the second porous plate 3, and then enter between the second porous plate 3 and the third porous plate 3, high-purity silicon carbide powder is also placed on the second porous plate 3, and the high-purity silicon carbide powder will also continue to grow through chemical vapor deposition, and so on. Several layers (at least three layers) of porous plates 3 can be set to fully utilize the reaction gas, wherein there is a gap between the uppermost (topmost) porous plate 3 and the upper cover 1.1, and no high-purity silicon carbide powder is placed on the uppermost porous plate 3, nor is the nozzle 4 placed.

[0043] Except for the uppermost porous plate 3, the remaining porous plates 3 are all placed with granular products; after completing one chemical vapor deposition, before the next chemical vapor deposition, at least part of the granular products on the upper porous plate 3 are placed on the lower porous plate 3 for the next chemical vapor deposition. It should be noted that the upper porous plate 3 here refers to the porous plates 3 except the lowermost porous plate 3, and the lower porous plate 3 here refers to any one or more porous plates 3 located below the previous specific porous plate 3. Preferably, the granular product is silicon carbide particles.

[0044] The chemical vapor deposition furnace 1 preferably adopts a bottom-opening mode. After completing a chemical vapor deposition phase, the lower cover body and cylinder body 2, porous plate 3 and nozzle 4 are lowered together, and the porous plate 3 and nozzle 4 are removed layer by layer from top to bottom, and the finished or semi-finished granular products are collected.

[0045] The embodiments of the present invention are described above in conjunction with the accompanying drawings. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention is not limited to the above-mentioned specific implementations, which are merely illustrative and not restrictive. Under the enlightenment of the present invention, those skilled in the art can also make many forms without departing from the scope of protection of the present invention and the claims, all of which belong to the protection scope of the present invention.

Claims

1. A chemical vapor deposition device for preparing a particle product, comprising a chemical vapor deposition furnace (1), the chemical vapor deposition furnace (1) comprising an upper cover (1.1) and a lower cover (1.2), the lower cover (1.2) being provided with an air inlet channel (1.3), the upper cover (1.1) being provided with an air outlet channel (1.4), characterized in that: It also includes a barrel (2), a porous plate (3) and a nozzle (4); The cylinder (2) is vertically arranged in the inner cavity of the chemical vapor deposition furnace (1); the upper end of the cylinder (2) abuts against the upper cover (1.1), and the lower end abuts against the lower cover (1.2); at least three supporting rings (2.1) are arranged on the inner wall of the cylinder (2); At least three porous plates (3) are arranged in the cylinder (2) at intervals along the vertical direction, and there is a gap between the lowest porous plate (3) and the lower cover (1.2); The porous plate (3) has a plurality of through holes (3.1), and the edge of the porous plate (3) is placed on the supporting ring (2.1); a plurality of nozzles (4) are arranged between two adjacent porous plates (3), and a plurality of through holes (4.1) are arranged on the side wall of the nozzle (4); the nozzle (4) is arranged vertically, and the lower end of the nozzle (4) abuts against the porous plate (3) below it, and the upper end of the nozzle (4) abuts against the porous plate (3) above it; the through holes (3.1) of the porous plate (3) below the nozzle (4) all correspond to the inner cavities of the plurality of nozzles (4), and the through holes (3.1) of the porous plate (3) above the nozzle (4) all correspond to the gaps between the plurality of nozzles (4).

2. A chemical vapor deposition device for preparing a particle product according to claim 1, characterized in that: The barrel (2), the porous plate (3) and the nozzle (4) are all made of graphite.

3. A chemical vapor deposition device for preparing a particle product according to claim 1, characterized in that: The cylinder (2) comprises a plurality of cylinder modules (2.2) which are stacked in a vertical direction, and each cylinder module (2.2) is provided with the supporting ring (2.1).

4. A chemical vapor deposition device for preparing a particle product according to claim 3, characterized in that: The upper end surface of the lower barrel module (2.2) has a circular ring protrusion (2.3) or a circular ring groove (2.4), and the lower end surface of the upper barrel module (2.2) has a circular ring groove (2.4) or a circular ring protrusion (2.3).

5. The chemical vapor deposition device for preparing a particle product according to claim 1, characterized in that: The cylinder (2) comprises a plurality of connecting rings (2.5) and a plurality of cylinder modules (2.2); two adjacent cylinder modules (2.2) in the vertical direction are connected via the connecting rings (2.5); and the supporting ring (2.1) is provided on the connecting rings (2.5) or the cylinder modules (2.2).

6. A chemical vapor deposition device for preparing a particle product according to claim 5, characterized in that: The upper end surface and the lower end surface of the barrel module (2.2) both have a circular ring protrusion (2.3) or a circular ring groove (2.4), and the upper end surface and the lower end surface of the connecting ring (2.5) both have a circular ring groove (2.4) or a circular ring protrusion (2.3).

7. A chemical vapor deposition device for preparing a particle product according to claim 1, characterized in that: The diameter of the through hole (3.1) of the porous plate (3) below the nozzle (4) is larger than the diameter of the through hole (3.1) of the porous plate (3) above the nozzle (4).

8. A chemical vapor deposition device for preparing a particle product according to claim 7, characterized in that: The diameter of the nozzle (4) below the porous plate (3) is larger than the diameter of the nozzle (4) above the porous plate (3), and the diameter of the through hole (4.1) of the nozzle (4) below the porous plate (3) is larger than the diameter of the through hole (4.1) of the nozzle (4) above the porous plate (3).

9. A method for preparing a particle product, using the chemical vapor deposition apparatus according to any one of claims 1 to 8, characterized in that: Except for the uppermost porous plate (3), the remaining porous plates (3) are all placed with granular products; after completing one chemical vapor deposition, before the next chemical vapor deposition, at least part of the granular products on the upper porous plate (3) are placed on the lower porous plate (3) for the next chemical vapor deposition.

10. The method according to claim 9, characterized in that The particle product is silicon carbide particles.

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