Reactor for synthesizing electronic grade silicon carbide powder
By using graphite crucible and graphite paper separation design in the silicon carbide powder synthesis reactor, the problems of uneven powder particle size and short service life of the crucible are solved, and high-purity and low-cost silicon carbide powder production are achieved.
Patent Information
- Application Number
- CN202420805603.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-18
- Publication Date
- 2024-12-13
- Estimated Expiration
- 2034-04-18
AI Technical Summary
In the existing silicon carbide powder synthesis reactor, silicon carbide powder needs further crushing treatment, impurities are introduced, yield is limited, and the crucible service life is short, and the sublimation of silicon atmosphere crystallization leads to difficulty in material extraction.
The graphite crucible design is adopted, and graphite paper is laid inside and outside the pot body and the lid body. The raw material cavity is separated into independent reaction chambers through graphite paper, and the thermal conductivity of graphite paper is used to uniformly transfer temperature, avoid direct contact between powder and crucible, and reduce the temperature. Uniformity.
The uniformity of the particle size of silicon carbide powder is achieved, which avoids impurities contamination during crushing, extends the service life of the crucible, and reduces production costs.
Smart Images
Figure CN222165658U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of semiconductor preparation, in particular to a reactor for synthesizing electronic-grade silicon carbide powder. Background Art
[0002] Silicon carbide is a third-generation semiconductor material developed after Si and GaAs (gallium arsenide) with wide bandgap, high thermal conductivity, high breakdown field strength, high carrier saturation and high radiation resistance. In recent years, it has rapidly penetrated into every corner of the fields of lighting, electronic power devices, etc., and the market size has increased rapidly. It has a wide application market in new energy vehicles, automotive lighting, general lighting, electric vehicles, 5G communication applications and other fields, and will become one of the directions of future new energy development.
[0003] At present, the self-propagating method is generally used to synthesize high-purity silicon carbide powder using high-purity graphite powder and high-purity silicon powder as raw materials. However, since the particle size of high-purity graphite powder and high-purity silicon powder is small, at the micron level, the thermal conductivity during the powder synthesis process is not high, resulting in a large temperature difference between the temperatures of various parts, resulting in uneven particle size of the synthesized powder. The obtained powder needs to be crushed, which inevitably causes contamination by external impurities in the process, making it difficult to obtain high-purity powder. For example, Chinese patent document CN211620665U discloses a reactor for preparing high-purity silicon carbide powder, in which a plurality of graphite plates with holes are used to separate the powder in a synthesis chamber, a gap is set above the powder area and the porous graphite plates, and the silicon raw material is heated in a heating furnace so as to sublime and react with the graphite plates to generate high-purity silicon carbide powder; although this method can obtain silicon carbide powder with higher purity, the powder needs to be further crushed and processed, impurities are introduced, and the output of the powder obtained by this structure is limited. At the same time, the sublimated silicon atmosphere will form crystals at the place where the porous graphite plate contacts the crucible wall, making it difficult to take out the material and reducing the service life of the crucible. Utility Model Content
[0004] The utility model aims to provide a reactor for synthesizing electronic-grade silicon carbide powder, so as to solve the problems that the silicon carbide powder generated by the reactor for synthesizing silicon carbide powder in the prior art has large-particle powder, needs to be further crushed, and introduces impurities; and the output of the powder obtained by the reactor for synthesizing silicon carbide powder in the prior art is limited, the material is difficult to obtain, and the service life of the crucible is reduced.
[0005] The technical scheme of the utility model is: a reactor for synthesizing electronic grade silicon carbide powder, a graphite crucible, the graphite crucible comprising a straight cylindrical pot body and a cover body arranged on the pot body; the bottom surface and the side wall inside the pot body are fully covered with a first graphite paper, and the inner surface of the cover body facing the pot body is fully covered with a second graphite paper; the first graphite paper and the second graphite paper are enclosed to form a raw material cavity, and the raw material cavity is divided into a plurality of independent reaction cavities by at least one third graphite paper, and a uniformly mixed carbon silicon powder is placed in each reaction cavity.
[0006] Preferably, the raw material chamber is divided into a plurality of independent reaction chambers in the horizontal direction or the vertical direction by at least one third graphite paper.
[0007] Preferably, a plurality of the third graphite papers are laid in parallel at equal intervals in the horizontal direction, and the edge of each graphite paper is attached to the vertical portion of the first graphite paper; each of the third graphite papers has ventilation holes evenly spaced thereon, and the diameter of the ventilation holes is 2-5 mm.
[0008] Preferably, a plurality of the third graphite papers are laid in parallel at equal intervals in the vertical direction, and the edge of each graphite paper is attached to the vertical part and the horizontal part of the first graphite paper.
[0009] Preferably, a plurality of the third graphite papers are cross-laid in a grid pattern along a vertical direction, and the edge of each graphite paper is attached to the vertical part and the horizontal part of the first graphite paper.
[0010] Preferably, the thickness of the first graphite paper, the second graphite paper, and the third graphite paper is 0.15-2 mm, and the density of the first graphite paper, the second graphite paper, and the third graphite paper is 0.7 g / cm 3 ~1.3g / cm 3 The laying thickness of the first graphite paper and the second graphite paper inside the pot body and the inner surface of the cover body is 0.15-3mm.
[0011] Preferably, the distance between two adjacent third graphite papers is 20-100 mm.
[0012] Preferably, the distance between two adjacent third graphite papers is 10-50 mm.
[0013] Preferably, the thickness of the pot body and the cover body are both 5-20 mm.
[0014] Compared with the prior art, the advantages of the utility model are:
[0015] (1) The present invention is a reactor for synthesizing electronic-grade silicon carbide powder. A more economical and effective graphite paper is used to separate the uniformly mixed carbon silicon powder into multiple components. The bottom surface and side walls of the crucible are separated from the carbon silicon powder by graphite paper, thereby effectively preventing the carbon silicon powder from reacting with the crucible, thereby making it difficult to remove the silicon carbide powder and reducing the service life of the crucible. At the same time, the use of graphite paper to isolate the carbon silicon powder can facilitate heat transfer to various parts through the graphite paper, making the temperature field more uniform. The graphite paper is thinner than the graphite block or graphite plate in the prior art, so that the heat capacity of the graphite paper is smaller than that of the graphite block and the graphite plate, and has less influence on the stable distribution of the temperature field. The graphite paper can well avoid the problem of uneven temperature.
[0016] (2) The utility model provides a reactor for synthesizing electronic-grade silicon carbide powder. The obtained silicon carbide powder has a relatively uniform particle size, and there is no large particle size. There is no need to consider external impurity contamination caused by subsequent crushing or grinding. At the same time, the graphite paper effectively protects the entire inner wall of the crucible, which can better avoid reducing the service life of the crucible. The cost of graphite paper is lower than that of graphite blocks or graphite plates. On the whole, the technical solution is relatively low in cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The utility model is further described below in conjunction with the accompanying drawings and embodiments:
[0018] Figure 1 This is a schematic diagram of the longitudinal section structure of a reactor for synthesizing electronic grade silicon carbide powder as described in Example 1;
[0019] Figure 2 This is a schematic diagram of the longitudinal section structure of a reactor for synthesizing electronic grade silicon carbide powder as described in Example 2;
[0020] Figure 3 This is a partial structural schematic diagram of a cross section of a reactor for synthesizing electronic grade silicon carbide powder described in Example 3;
[0021] Figure 4 This is a schematic diagram of the structure in which the third graphite paper B and the third graphite paper A described in the third embodiment are inserted into each other.
[0022] Wherein: 1. pot body, 2. cover body, 3. first graphite paper, 4. second graphite paper, 5. third graphite paper, 6. reaction chamber, 7. carbon silicon powder, 8. third graphite paper A, 9. third graphite paper B, 10. graphite heating element, 11. graphite felt, 12. notch A, 13. notch B. DETAILED DESCRIPTION
[0023] The following is a further detailed description of the present invention in conjunction with specific embodiments:
[0024] In the description of the utility model, it is necessary to understand that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model.
[0025] Embodiment 1
[0026] like Figure 1 As shown, a reactor for synthesizing electronic grade silicon carbide powder, a graphite crucible, the graphite crucible comprising a straight cylindrical pot body 1, a cover body 2 covered on the pot body 1; the bottom surface and side walls inside the pot body 1 are fully covered with a first graphite paper 3, and the inner surface of the cover body 2 facing the pot body 1 is fully covered with a second graphite paper 4. Specifically, the second graphite paper 4 can be directly placed on the pot mouth of the pot body 1, and then the cover body 2 is covered so that the inner surface of the cover body 2 facing the pot body 1 is not exposed; in this embodiment, the bottom surface and side walls inside the pot body 1, as well as the inner surface of the cover body 2 facing the pot body 1 are fully covered with graphite paper, so as to avoid the direct contact and reaction between the powder and the crucible during the synthesis process, resulting in the formed silicon carbide sticking to the crucible. The first graphite paper 3 and the second graphite paper 4 enclose a raw material chamber, and the raw material chamber is divided into a plurality of independent reaction chambers 6 by at least one third graphite paper 5, and each reaction chamber 6 is filled with a uniformly mixed carbon silicon powder 7; in this embodiment, the third graphite paper 5 is used to separate the uniformly mixed carbon silicon powder 7 into several portions, and the heat conduction of the graphite paper is used to evenly transfer the temperature to the inside of the powder, so that the temperature is evenly distributed during the synthesis of the powder, which is conducive to the synthesis of silicon carbide powder with uniform particle size, and does not require subsequent crushing treatment, avoiding contamination by external impurities, and is conducive to obtaining high-purity silicon carbide powder. The raw material chamber is divided into a plurality of independent reaction chambers 6 in the horizontal or vertical direction by at least one third graphite paper 5.
[0027] A plurality of third graphite papers 5 are laid in parallel at equal intervals in the horizontal direction, and the edge of each graphite paper is attached to the vertical part of the first graphite paper 3 (i.e., the part of the first graphite paper 3 attached to the side wall of the pot body 1). Specifically, firstly, the mixed carbon silicon powder 7 is placed on the bottom surface of the pot body 1, and then the first third graphite paper 5 is placed horizontally on the mixed carbon silicon powder 7, and then the second mixed carbon silicon powder 7 is placed on the first third graphite paper 5. Since the graphite paper has a certain hardness and the carbon silicon powder 7 is very light, the third graphite paper 5 can basically maintain a flat shape, and then the second third graphite paper 5 is placed on the second mixed carbon silicon powder 7, and the materials are placed in sequence. The top surface of the top mixed carbon silicon powder 7 should be at a distance of 1.5 meters from the top. The crucible cover 2 is maintained at 10-20 mm, so that the volatile gas in the powder synthesis process can be effectively discharged, and at the same time, the material surface is prevented from directly contacting with the inner surface of the crucible cover 2 due to volume expansion during the powder synthesis process; in the present embodiment, each third graphite paper 5 is evenly provided with vent holes (not shown in the figure), the diameter of the vent holes is 2-5 mm, preferably 3-5 mm, the diameter of the vent holes on the third graphite paper 5 should not be too small or too large, and the vent holes are too small and are easily blocked during the powder synthesis process, and the vent holes lose the function of removing gas; if the diameter of the vent holes is too large, the surface area of the powder in contact with the third graphite paper 5 will be reduced, and the effect of temperature conduction using the third graphite paper 5 will be reduced, and the effect of changing the internal temperature of the powder will not be achieved. In actual production, after the evenly mixed carbon silicon powder 7 and the third graphite paper 5 are placed, the cover 2 of the crucible is covered, and the crucible is placed in a graphite heating element 10 with a graphite felt 11 laid on the outer surface to carry out the silicon carbide powder synthesis process.
[0028] The thickness of the first graphite paper 3, the second graphite paper 4, and the third graphite paper 5 is 0.15-2 mm, preferably 0.25-1 mm; the density of the first graphite paper 3, the second graphite paper 4, and the third graphite paper 5 is 0.7 g / cm 3 ~1.3g / cm 3 The thickness of the first graphite paper 3 and the second graphite paper 4 inside the pot body 1 and the inner surface of the cover body 2 is 0.15-3 mm, preferably 0.25-2 mm, to prevent the carbon silicon powder 7 from reacting with the graphite crucible to form silicon carbide and bonding together, which is not conducive to the removal of the powder. The spacing between two adjacent third graphite papers 5 is 20-100 mm, preferably 35-50 mm. The thickness of the pot body 1 and the cover body 2 is 5-20 mm, preferably 10-15 mm.
[0029] Embodiment 2
[0030] The difference between the second embodiment and the first embodiment is that Figure 2As shown, multiple third graphite papers 5 are laid in parallel at equal intervals in the vertical direction, and the edge of each graphite paper fits the vertical part (i.e., the part of the first graphite paper 3 attached to the side wall of the pot body 1) and the horizontal part (i.e., the part of the first graphite paper 3 attached to the bottom surface of the pot body 1) of the first graphite paper 3; specifically, from left to right, the evenly mixed carbon silicon powder 7 and the third graphite paper 5 can be placed alternately, or multiple third graphite papers 5 can be laid in parallel at equal intervals in the vertical direction first, and then multiple portions of the evenly mixed carbon silicon powder 7 are placed in the reaction chamber 6 respectively. In this embodiment, the distance between two adjacent third graphite papers 5 is 10-50 mm, preferably 20-35 mm.
[0031] Embodiment 3
[0032] The difference between the third embodiment and the first embodiment is that Figure 3 As shown, multiple third graphite papers are laid crosswise in the vertical direction to form a grid, and the edge of each graphite paper fits the vertical part and the horizontal part of the first graphite paper 3. Specifically, the upper end of the third graphite paper A8 placed vertically and parallelly in the first direction is provided with multiple notches A12 in the vertical direction, and the lower end of the third graphite paper B9 placed vertically and parallelly in the second direction is provided with multiple notches B13 in the vertical direction, and then the third graphite paper B9 is stuck on the notches A12 of the third graphite paper A8 to form a grid, and then the mixed carbon silicon powder 7 divided into multiple portions is placed in each reaction chamber 6, Figure 4 This is a schematic diagram of a card insertion with a single notch; cards with multiple notches are the same.
[0033] It should be noted that, in both Example 2 and Example 3, the evenly mixed carbon silicon powder 7 is divided into several portions and isolated by a third graphite paper, and the temperature is evenly transferred to the inside of the powder by utilizing the heat conduction of the graphite paper, so that the temperature is evenly distributed during the powder synthesis process, which is conducive to the synthesis of silicon carbide powder with uniform particle size, and does not require subsequent crushing processing, thereby avoiding contamination by external impurities and facilitating the acquisition of high-purity silicon carbide powder.
[0034] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with this technology to understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. For those skilled in the art, it is obvious that the utility model is not limited to the details of the above exemplary embodiments, and the utility model can be implemented in other specific forms without departing from the spirit or basic features of the utility model. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the utility model is limited by the attached claims rather than the above description, so it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the utility model.
Claims
1. A reactor for synthesizing electronic grade silicon carbide powder, characterized in that: include: A graphite crucible, comprising a straight cylindrical pot body and a cover body arranged on the pot body; the bottom surface and side walls of the pot body are fully covered with a first graphite paper, and the inner surface of the cover body facing the pot body is fully covered with a second graphite paper; the first graphite paper and the second graphite paper enclose a raw material cavity, and the raw material cavity is divided into a plurality of independent reaction cavities by at least one third graphite paper, and each reaction cavity is filled with a uniformly mixed carbon silicon powder.
2. A reactor for synthesizing electronic grade silicon carbide powder according to claim 1, characterized in that: The raw material chamber is divided into a plurality of independent reaction chambers in the horizontal direction or the vertical direction by at least one third graphite paper.
3. A reactor for synthesizing electronic grade silicon carbide powder according to claim 2, characterized in that: A plurality of the third graphite papers are laid in parallel at equal intervals in the horizontal direction, and the edge of each graphite paper is attached to the vertical part of the first graphite paper; each of the third graphite papers has ventilation holes evenly spaced thereon, and the diameter of the ventilation holes is 2-5 mm.
4. A reactor for synthesizing electronic grade silicon carbide powder according to claim 2, characterized in that: A plurality of the third graphite papers are laid in parallel at equal intervals in the vertical direction, and the edge of each graphite paper is attached to the vertical part and the horizontal part of the first graphite paper.
5. A reactor for synthesizing electronic grade silicon carbide powder according to claim 2, characterized in that: The plurality of third graphite papers are cross-laid in a grid shape along a vertical direction, and the edge of each graphite paper is attached to the vertical part and the horizontal part of the first graphite paper.
6. A reactor for synthesizing electronic grade silicon carbide powder according to claim 1, characterized in that: The thickness of the first graphite paper, the second graphite paper and the third graphite paper is 0.15-2 mm, and the density of the first graphite paper, the second graphite paper and the third graphite paper is 0.7 g / cm 3 ~1.3g / cm 3 The laying thickness of the first graphite paper and the second graphite paper inside the pot body and the inner surface of the cover body is 0.15-3mm.
7. A reactor for synthesizing electronic grade silicon carbide powder according to claim 3, characterized in that: The distance between two adjacent third graphite papers is 20-100 mm.
8. A reactor for synthesizing electronic grade silicon carbide powder according to claim 4, characterized in that: The distance between two adjacent third graphite papers is 10-50 mm.
9. A reactor for synthesizing electronic grade silicon carbide powder according to claim 1, characterized in that: The thickness of the pot body and the cover body is 5-20 mm.