Silicon carbide crystal growth thermal field structure

Abstract

The utility model discloses a silicon carbide crystal growth thermal field structure which comprises a crucible, a separation part, an exhaust assembly and a heat preservation cylinder, and a mounting ring is arranged in the crucible and is tightly attached to the inner side of the crucible; the partition part comprises a plurality of partition plates, vent holes are formed in the partition plates, the partition plates are installed in the crucible at intervals from top to bottom, a plurality of raw material spaces are defined in the crucible, and the partition plate from the bottommost layer to the partition plate on the second top layer can be fractured and sink after being corroded; silicon carbide powder is contained in the raw material space, and the closer to the raw material space of the crystal growth interface, the smaller the particle size of the silicon carbide powder in the raw material space is, and the higher the purity is; the exhaust assembly covers the upper part of the crucible; seed crystals are mounted on the top wall in the exhaust assembly; the heat preservation cylinder wraps the crucible, and a set gap is formed between the top wall of the heat preservation cylinder and the top wall of the exhaust assembly. According to the utility model, the problems of effective utilization of a silicon carbide powder source and concave crystal growth surface in the PVT method can be solved.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, in particular to a silicon carbide crystal growth thermal field structure. Background Art

[0002] Related technologies point out that the core of physical vapor transport (PVT) silicon carbide crystal growth is composed of graphite thermal field (such as the entire crucible), insulation system (such as graphite felt), raw materials (seed crystal growth raw materials), etc. At a higher temperature (about 2300 ° C or more) and a lower gas phase pressure, the silicon carbide powder in the graphite crucible (the powder source at the bottom of the crucible) undergoes non-stoichiometric decomposition and sublimation to generate various forms of metastable gas phase components Si m C n At the same time, the silicon carbide powder is sintered inside to form a ceramic body with a large number of pores. This is because the physical vapor transport (PVT method) itself has inherent defects. Whether it is induction heating or resistance heating, in the PVT method, a temperature gradient must exist to meet the requirements of the gas phase component Si. m C n Axial or radial transport occurs. Due to the existence of axial temperature gradient, the SiC powder will be transported from the source area to the growth interface and aggregated for crystallization (in actual experience, the growth thickness of the crystal after a cycle and the surface shape of the growth interface have a strong correspondence with the powder source treatment. The gas phase component Si m C n Deposition and crystallization are carried out on the growth interface, so that the growth interface gradually moves toward the raw material area. As the growth progresses, the interface of the residual ceramic body after the PVT method silicon carbide crystal growth is completed is analyzed. The specific analysis steps are: ① Cut the residual material in the crucible longitudinally along its diameter, and pay attention to protecting the integrity of the residual material cross-section as much as possible; ② Observe the graphitization of the residual material, such as the bottom and surrounding areas of the material; ③ Find the high-temperature zone (in the PVT method crystal growth, in order to maintain the stability of growth, the thermal field is usually almost determined relative to the coil position, power, heating time, etc., and clarifying the position of the high-temperature zone is the key information for determining the crystal growth process. After the high-temperature zone is stable, the subsequent crystal growth process is only a fine-tuning of the process).

[0003] The cross-section of the residual ceramic body after the PVT method silicon carbide crystal growth is analyzed, the recrystallization zone (that is, a large number of columnar 6H-SiC grains are formed in this area. This is because in the radial direction of the thermal field, the temperature gradually decreases from the outer edge of the graphite crucible to the center inner area. Whether it is the "skin effect" of induction heating or the heat conduction of resistance heating, this trend is inevitable, and the recrystallization zone of the induction heating system is particularly obvious); the graphitization zone (that is, the high temperature zone, where C-rich particles and graphite particles are generated); although the particles in the ceramic body will continue to undergo sintering reactions in the middle and late stages of crystal growth, some positions form channels that converge from the bottom upward and toward the crystal extension surface, which makes the subsequent gas phase component Si mC n The silicon carbide gas is transported along these channels to the gas phase (crystal growth zone), but a large number of ceramic bodies are formed and accumulated in the relatively cold temperature zone. On the one hand, this affects the efficiency of powder source utilization, and on the other hand, it hinders the rate at which the silicon carbide gas rises to the crystal growth zone. Therefore, there is an urgent need for a thermal field structure to solve the problem of efficient utilization of silicon carbide powder source and concave growth surface in PVT method. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a silicon carbide crystal growth thermal field structure that can solve the problems of efficient utilization of silicon carbide powder source and concave crystal growth surface in the PVT method.

[0005] According to the utility model, the silicon carbide crystal growth thermal field structure includes a crucible, a partition component, an exhaust assembly and an insulation cylinder. The partition component includes a plurality of partitions, each of which is provided with a vent hole. The plurality of partitions are installed in the crucible from top to bottom, defining a plurality of raw material spaces inside the crucible. The partitions from the bottom layer to the second top layer can break and sink after being corroded. Silicon carbide powder is contained in the raw material space, and the closer the raw material space is to the crystal growth interface, the smaller the particle size of the silicon carbide powder inside and the higher the purity. The exhaust assembly covers the upper part of the crucible, and a seed crystal is installed on the top wall of the exhaust assembly. The insulation cylinder is wrapped around the outside of the crucible, and a set gap is provided between the top wall of the insulation cylinder and the top wall of the exhaust assembly.

[0006] Preferably, in some embodiments, the exhaust assembly of the present invention is an annular structure, and a connecting portion extends radially outward from the upper portion of the exhaust assembly, and the exhaust assembly is covered on the upper portion of the crucible through the connecting portion, and the bottom of the exhaust assembly is in close contact with the upper surface of the top partition, and there is a certain gap between the outer wall of the exhaust assembly and the inner wall of the crucible; the upper portion of the exhaust assembly defines an annular groove for accommodating a graphite cover plate, and an annular graphite pressure plate is placed on the upper portion of the graphite cover plate, the outer diameter of the annular graphite pressure plate is equal to the outer diameter of the graphite cover plate, and the width of the annular graphite pressure plate is the same as the width of the annular groove, the graphite cover plate is the top wall of the exhaust assembly, the seed crystal is mounted on the lower surface of the graphite cover plate, the top partition, the graphite cover plate and the inner wall of the exhaust assembly jointly define a growth space for crystal growth; exhaust holes are provided on the side walls of the exhaust assembly and the connecting portion.

[0007] Preferably, in some embodiments, the utility model has three partitions in total, including a first partition, a second partition and a third partition, the first partition, the second partition and the third partition are all circular structures, the first partition, the second partition and the third partition are installed in sequence from bottom to top inside the crucible, the first partition and the inner bottom wall and side wall of the crucible jointly define a first raw material space, the first partition, the second partition and the inner wall of the crucible jointly define a second raw material space, and the second partition, the first partition and the inner wall of the crucible jointly define a third raw material space.

[0008] Preferably, in some embodiments, the silicon carbide powder contained in the first raw material space of the utility model has a particle size of 10-20 mesh and a purity of 99.999%; the silicon carbide powder contained in the second raw material space has a particle size of 30-40 mesh and a purity of 99.999%; the silicon carbide powder contained in the third raw material space has a particle size of 50-60 mesh and a purity of 99.999%; the silicon carbide powder above the third partition has a particle size of 80-100 mesh and a purity of 99.9999999%. In this embodiment, the first raw material space is located at the bottom of the crucible, closest to the high-temperature zone and farthest from the crystal growth interface. Therefore, the silicon carbide powder in the first raw material space has a larger particle size and lower purity. This is because the larger particle size of silicon carbide powder can maintain a lower decomposition rate. Maintaining a lower decomposition rate of silicon carbide powder in the high-temperature zone can, on the one hand, reduce the heterogeneity of the gas phase components caused by rapid decomposition, thereby reducing the probability of polymorphic, point defects, and line defects in the crystal, improving the quality of the crystal. On the other hand, it can reduce the amount of carbon generated, thereby reducing the density of carbon inclusions in the crystal, and improving the purity and performance of the crystal. In addition, because the first raw material space is far from the crystal growth interface, and high-purity silicon carbide powder is placed on the upper part of the third partition, i.e., above the crucible, to act as a filter, the silicon carbide powder on the upper part of the third partition can inhibit the adsorption of impurity atoms on the crystal growth interface in the early stages of crystal growth. In other words, the silicon carbide powder on the upper part of the third partition has a filtering effect on the silicon carbide powder in the crucible. Therefore, the first raw material space does not require high-purity silicon carbide powder; a basic purity of not less than 5N is sufficient, reducing production costs. The silicon carbide powder above the third partition is farthest from the high-temperature zone and requires a minimum particle size to maintain a high decomposition rate when the temperature reaches the decomposition temperature, which is beneficial to improving the growth rate of the crystal. Since the purity of the silicon carbide powder inside the crucible is relatively low, the silicon carbide powder placed above the third partition has a higher purity, which plays a filtering role on the silicon carbide gas sublimated from the crucible, especially avoiding carbon encapsulation defects, which is beneficial to improving the growth quality of the crystal.

[0009] Preferably, in some embodiments, the first partition and the second partition of the present invention both include a main body component and an edge connection portion extending radially outward from the main body component.

[0010] Preferably, in some embodiments, the main body component of the first partition of the present invention is 10-15mm thick, the edge connection portion is 4-6mm thick, and the vertical height of the first raw material space is 50-60mm; the main body component of the second partition is 5-8mm thick, the edge connection portion is 2-3mm thick, and the vertical height of the second raw material space is 10-15mm; the third partition is 10-15mm thick, and the vertical height of the third raw material space is 10-15mm; the ventilation holes are evenly distributed on the first partition main body component, the second partition component and the third partition, and the diameter of the ventilation holes is 2mm.

[0011] Preferably, in some embodiments, the first baffle body component of the present invention is connected to the edge connection portion of the first baffle through a first connecting ring, the thickness of the main component and the edge connection portion of the first baffle is 10-15 mm, the thickness of the first connecting ring is 4-6 mm, the diameter of the first baffle body component is 120-140 mm (6-inch hot field), and the vertical height of the first raw material space is 50-60 mm; the main component of the second baffle is connected to the edge connection portion of the second baffle through a second connecting ring, and the thickness of the main component of the second baffle is 5-8 mm, the thickness of the second connecting ring is 2-3mm, the thickness of the second partition edge connection part is 10-15mm, the diameter of the main part of the second partition is 180-196mm (6-inch hot field), and the vertical height of the second raw material space is 10-15mm; the thickness of the third partition is 10-15mm, and the vertical height of the third raw material space is 10-15mm; the ventilation holes are evenly distributed on the first partition main part, the second partition main part, the second partition edge connection part and the third partition, and the diameter of the ventilation holes is 2mm.

[0012] Preferably, in some embodiments, the present invention further includes a first mounting plate, a second mounting plate and a third mounting plate, and the first mounting plate, the second mounting plate and the third mounting plate are all annular structures, and an annular groove is defined on the upper portion of the first mounting plate, the second mounting plate and the third mounting plate, and the edge connecting portions of the first partition plate and the second partition plate and the outer bottom of the third partition plate are connected with a mounting ring, and the first partition plate, the second partition plate and the third partition plate are respectively connected to the first mounting plate, the second mounting plate and the third mounting plate through the cooperation of the mounting ring and the annular groove, and the first mounting plate, the second mounting plate and the third mounting plate are placed inside the crucible from bottom to top by mutual embedding, and are close to the inner wall of the crucible.

[0013] Compared with the prior art, the present invention has the following excellent effects:

[0014] 1) Multiple partitions are arranged from bottom to top inside the crucible to divide the inside of the crucible into multiple raw material spaces from bottom to top. The closer the raw material space is to the crystal growth interface, the smaller the particle size of the silicon carbide powder inside it and the higher the purity. During the crystal growth process, the partition inside the crucible will be corroded and broken, and thus move downward. The silicon carbide powder on the upper part of the partition will also move downward to the area close to the high temperature zone. On the one hand, the broken and downward movement of the partition avoids the formation of a ceramic body in the low temperature zone at the upper center of the crucible, thereby improving the effective utilization rate of the silicon carbide powder. On the other hand, the silicon carbide powder on the upper part of the partition moves downward to the high temperature zone, which is beneficial to increase the decomposition rate of the silicon carbide powder, thereby increasing the growth rate of the crystal.

[0015] 2) The utility model avoids the formation of ceramic bodies in the powder source. When silicon carbide powder sublimates into silicon carbide gas, there is no obstruction of the ceramic body during the rising process, so that the crystal growth surface is flat, avoiding the technical problem of a concave crystal growth surface, and effectively improving the crystal quality.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of a thermal field structure for silicon carbide crystal growth according to one embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of a thermal field structure for silicon carbide crystal growth according to one embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of an exhaust pipe assembly of a silicon carbide crystal growth thermal field structure according to an embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of the partition and mounting plate structure of the silicon carbide crystal growth thermal field structure according to one embodiment of the present utility model;

[0021] Figure 5 This is a high temperature zone distribution diagram of a silicon carbide crystal growth thermal field structure according to one embodiment of the present utility model;

[0022] Figure 6 This is a diagram showing the positions of the first and second baffles of the silicon carbide crystal growth thermal field structure in the middle and late stages of crystal growth according to one embodiment of the present invention;

[0023] Figure 7 This is a schematic diagram of the thermal field structure of silicon carbide crystal growth according to one embodiment of the present utility model;

[0024] Figure 8This is a schematic diagram of the thermal field structure of silicon carbide crystal growth according to one embodiment of the present utility model;

[0025] Figure 9 This is a schematic diagram of the partition and mounting plate structure of the silicon carbide crystal growth thermal field structure according to one embodiment of the present utility model;

[0026] Figure 10 This is a high temperature zone distribution diagram of a silicon carbide crystal growth thermal field structure according to one embodiment of the present utility model;

[0027] Figure 11 This is a diagram showing the positions of the first and second baffles of the silicon carbide crystal growth thermal field structure in the middle and late stages of crystal growth according to one embodiment of the present invention;

[0028] Reference numerals:

[0029] 100: Thermal field structure of silicon carbide crystal growth;

[0030] 10: seed crystal;

[0031] 20: Crucible;

[0032] 30: exhaust assembly; 31: connection part; 311: exhaust hole; 32: annular graphite pressure plate; 33: graphite cover plate;

[0033] 40: Vent; 401: Edge connection; 402: Mounting ring; 41: First partition; 411: First raw material space; 412: First mounting plate; 414: First connecting ring; 403: Main body; 42: Second partition; 421: Second raw material space; 422: Second mounting plate; 424: Second connecting ring; 43: Third partition; 431: Third raw material space; 432: Third mounting plate;

[0034] 50: Insulation tube;

[0035] 60: electromagnetic induction coil;

[0036] 70: Ceramic body. DETAILED DESCRIPTION

[0037] The following describes in detail embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0038] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but a person of ordinary skill in the art will appreciate the applicability of other processes and / or the use of other materials.

[0039] Example 1

[0040] Reference below Figures 1 to 6 The silicon carbide crystal growth thermal field structure 100 according to an embodiment of the present invention is described, including a crucible 20, a partition component, an exhaust assembly 30, an insulation cylinder 50, and an electromagnetic induction coil 60. The partition component includes multiple partitions, and the partitions are provided with air holes 40. The air holes 40 are mainly used to filter impurities in the silicon carbide gas to improve the growth quality of the crystal. Multiple partitions are installed in intervals from top to bottom inside the crucible 20, defining multiple raw material spaces within the crucible 20. The partitions from the bottom to the next top can break and sink after corrosion. The raw material spaces contain silicon carbide powder, and the closer the raw material space is to the crystal growth interface, the smaller the particle size and the higher the purity of the silicon carbide powder inside. The exhaust assembly 30 covers the top of the crucible 20, and the top wall of the exhaust assembly 30 is installed with a seed crystal 10. The insulation tube 50 wraps around the outside of the crucible 20, and a set gap is formed between the top wall of the insulation tube 50 and the top wall of the exhaust assembly 30. Specifically, the insulation tube 50 is sealed at both top and bottom. The crucible 20 and the exhaust assembly 30 are both placed inside the insulation tube 50. The insulation tube 50 is mainly used to maintain the internal temperature of the crucible 20. The electromagnetic induction coil 60 surrounds the outside of the insulation tube 50 and is used to heat the crucible 20. In this embodiment, the crucible 20 is a graphite crucible 20, the insulation tube 50 is made of insulation felt, and the partitions are graphite plates.

[0041] Specifically, the decomposition rate of silicon carbide powder in the high-temperature zone within crucible 20 is low, and the resulting gaseous components are more uniform, which helps reduce the probability of polymorphic, point, and line defects forming in the crystal, thereby improving the quality of the crystal. Furthermore, the low decomposition rate reduces the amount of carbon generated, thereby reducing the density of carbon inclusions in the crystal, thereby improving the purity and performance of the crystal. As the temperature decreases, the smaller the particle size and the higher the purity of the silicon carbide powder, the more beneficial the crystal growth. Since the bottom of crucible 20 is the high-temperature zone, the temperature gradually decreases from the bottom to the top of crucible 20. Therefore, in this embodiment, the closer the raw material space is to the crystal growth interface, the smaller the particle size of the silicon carbide powder within it. Furthermore, since the high-temperature zone is farthest from the crystal growth interface, the lower the purity requirement for silicon carbide is. However, near the crystal growth interface, higher-purity silicon carbide powder is required, which helps improve the overall quality of the silicon carbide crystal. Therefore, in this embodiment, the closer the raw material space is to the crystal growth interface, the higher the purity of the silicon carbide powder within it.

[0042] During the crystal growth process, as the silicon carbide powder in the high temperature zone is continuously decomposed by heat, a large amount of metastable gas phase components SimCn are formed. The metastable SimCn gas phase continuously corrodes the partition in the high temperature zone. As the reaction proceeds, the partition will be corroded and gradually fail, and eventually break in the middle and late stages of the crystal, causing the partition to sink. Figure 3 and Figure 4 As shown, as the partition sinks, the silicon carbide powder above the broken partition (i.e., the silicon carbide powder away from the high temperature zone) will move to the high temperature zone, thereby avoiding the formation of the 6H-SiC ceramic body 70. Similarly, this phenomenon will also occur on other partitions. Through the above reaction, the utilization efficiency of the silicon carbide powder is effectively improved, the formation of the ceramic body 70 is avoided, the circulation of the gas phase component SimCn is hindered, the quality of the crystal is improved, and the production cost is reduced.

[0043] refer to Figure 1 and Figure 3As shown, in some embodiments, the exhaust assembly 30 of this embodiment is an annular structure, and a connecting portion 31 extends radially outward from the upper portion of the exhaust assembly 30. The exhaust assembly 30 is covered on the upper portion of the crucible 20 through the connecting portion 31, and the bottom of the exhaust assembly 30 is in close contact with the upper surface of the top partition, and there is a certain gap between the outer wall of the exhaust assembly 30 and the inner wall of the crucible 20; the upper portion of the exhaust assembly 30 defines an annular groove for accommodating a graphite cover plate 33, and an annular graphite pressure plate 32 is placed on the upper portion of the graphite cover plate 33. The outer diameter of the annular graphite pressure plate 32 is equal to the outer diameter of the graphite cover plate 33, and the width of the annular graphite pressure plate 32 is the same as the width of the annular groove, and the graphite cover plate 33 is an exhaust. The seed crystal 10 is installed on the top wall of the gas component 30 and the lower surface of the graphite cover plate 33. The top partition, the graphite cover plate 33 and the inner wall of the exhaust component 30 jointly define a growth space for crystal growth; exhaust holes 311 are provided on the side walls of the exhaust component 30 and the connecting part 31. The exhaust holes 311 effectively prevent excessive components from evaporating during the crystal growth process and depositing at the edge of the crystal. Specifically, the crystallization rate of the crystal is determined by the axial temperature gradient designed by the heat field. The setting of the exhaust holes 311 can discharge the interference of excess components out of the crystal growth area to avoid adverse factors such as excessive components leading to a fast initial growth rate and uncontrollable crystal weight gain leading to a decrease in crystal quality.

[0044] refer to Figure 1 and Figure 4 As shown, in some embodiments, there are three partitions in this embodiment, including a first partition 41, a second partition 42 and a third partition 43. The first partition 41, the second partition 42 and the third partition 43 are all circular structures. The first partition 41, the second partition 42 and the third partition 43 are installed in sequence from bottom to top inside the crucible 20. The first partition 41 and the inner bottom wall and side wall of the crucible 20 jointly define a first raw material space 411. The first partition 41, the second partition 42 and the inner wall of the crucible 20 jointly define a second raw material space 421. The second partition 42, the first partition 41 and the inner wall of the crucible 20 jointly define a third raw material space 431.

[0045] Preferably, in some embodiments, the silicon carbide powder contained in the first raw material space 411 of this embodiment has a particle size of 10-20 mesh and a purity of 99.999%; the silicon carbide powder contained in the second raw material space 421 has a particle size of 30-40 mesh and a purity of 99.999%; the silicon carbide powder contained in the third raw material space 431 has a particle size of 50-60 mesh and a purity of 99.999%; the silicon carbide powder above the third partition 43 has a particle size of 80-100 mesh and a purity of 99.9999999%. In this embodiment, the first raw material space 411 is located at the bottom of the crucible 20, closest to the high-temperature zone and farthest from the crystal growth interface. Therefore, the silicon carbide powder in this raw material area has a larger particle size and lower purity. This is because larger-particle silicon carbide powder can maintain a lower decomposition rate. Maintaining a lower decomposition rate in the high-temperature zone can, on the one hand, reduce the heterogeneity of the gas phase components caused by rapid decomposition, thereby reducing the probability of polymorphic, point, and line defects in the crystal, improving the quality of the crystal. On the other hand, it can reduce the amount of carbon generated, thereby reducing the density of carbon inclusions in the crystal, and improving the purity and performance of the crystal. In addition, because the first raw material space is farthest from the crystal growth interface, and the high-purity silicon carbide powder above the third partition can filter the silicon carbide gas sublimated from the lower part, improving the cleanliness of the silicon carbide gas, high-purity silicon carbide powder is not required here, reducing production costs. The silicon carbide powder above the third partition 43 is farthest from the high temperature zone, and small-sized silicon carbide powder is required to maintain a high decomposition rate when the temperature reaches the decomposition temperature, which is beneficial to improving the growth rate of the crystal. Since the silicon carbide powder there is closest to the crystal growth surface, the use of silicon carbide powder with higher purity is beneficial to improving the growth quality of the crystal. In addition, the silicon carbide powder placed above the third partition has a higher purity, which plays a role in filtering the silicon carbide gas sublimated from the crucible 20, especially avoiding carbon encapsulation defects. This is because: crystal defects often occur in the early stage of crystal growth, such as dislocations, phase changes, carbon encapsulation, etc. Among them, the purity of the powder, especially It is the carbon encapsulation caused by the non-stoichiometric biochemical reaction of metal elements in the powder or silicon carbide powder during the crystal growth process. When the axial temperature gradient (in the early stage of crystal growth) is large, the carbon in the powder will gather toward the center of the crystal, thereby forming fine carbon encapsulation. Therefore, a higher purity powder source (5N and above) is usually required during the growth of silicon carbide crystals. In this embodiment, a group of higher purity silicon carbide powder is placed on the upper part of the third partition 43. During the crystal growth process, it can filter the silicon carbide gas sublimated from the high temperature zone at the bottom, which is beneficial to maintain the cleanliness of the crystal growth interface in the early stage of crystal growth and effectively avoid crystal carbon encapsulation defects.

[0046] Of course, appropriate silicon carbide powder can also be selected according to actual conditions, based on the principle that the closer the raw material space is to the crystal growth interface, the smaller the silicon carbide powder particle size and the higher the purity.

[0047] refer to Figure 4 As shown, in some embodiments, the first partition 41 and the second partition 42 of this embodiment both include a main body part 403 and an edge connection portion 401 extending radially outward from the main body part 403. Specifically, in this embodiment, the main body part 403 of the first partition 41 has a thickness of 10-15 mm, the edge connection portion 401 has a thickness of 4-6 mm, and the vertical height of the first raw material space 411 is 50-60 mm; the main body part 403 of the second partition 42 has a thickness of 5-8 mm, the edge connection portion 401 has a thickness of 2-3 mm, and the vertical height of the second raw material space 421 is 10-15 mm; the third partition 43 has a thickness of 10-15 mm, and the vertical height of the third raw material space 431 is 10-15 mm; the vents 40 are evenly distributed on the main body part 403 of the first partition 41, the second partition 42 and the third partition 43, and the diameter of the vents 40 is 2 mm.

[0048] In this embodiment, the thickness of the main part 403 of the first partition 41 and the second partition 42 is greater than the thickness of the edge connection part 401 thereof. The edge connection part 401 is thin, which is convenient for being corroded and broken during the crystal growth process. After the edge connection part 401 of the first partition 41 and the second partition 42 is corroded and broken, the main part 403 of the first partition 41 and the second partition 42 moves downward, and the silicon carbide powder in the second raw material space 421 and the third raw material space 431 also moves downward, so that the silicon carbide powder originally in the low temperature zone (located at the upper center position of the crucible 20) moves downward to the area close to the high temperature zone, which is conducive to the decomposition and sublimation of the silicon carbide powder. On the one hand, it avoids the formation of the ceramic body 70, and on the other hand, it improves the effective utilization rate of the silicon carbide powder. Figure 5 and Figure 6 shown.

[0049] refer to Figure 1 and Figure 4 As shown, in some embodiments, the present invention further includes a first mounting plate 412, a second mounting plate 422, and a third mounting plate 432. The first mounting plate 412, the second mounting plate 422, and the third mounting plate 432 are all annular structures. An annular groove is defined on the upper portion of the first mounting plate 412, the second mounting plate 422, and the third mounting plate 432. A mounting ring 402 is connected to the edge connecting portion 401 of the first partition 41 and the second partition 42, and the outer bottom of the third partition 43. The first partition 41, the second partition 42, and the third partition 43 are respectively connected to the first mounting plate 412, the second mounting plate 422, and the third mounting plate 432 through the cooperation of the mounting ring 402 and the annular groove. The first mounting plate, the second mounting plate 422, and the third mounting plate 432 are placed inside the crucible 20 from bottom to top by being embedded in each other and closely attached to the inner wall of the crucible 20. In this embodiment, the partitions are mounted by mounting plates, which facilitates installation and removal of the partitions.

[0050] Example 2

[0051] This embodiment is substantially the same as the first embodiment, except that a connecting ring is connected between the main body 403 and the edge connecting portion 401 of the first and second separators 41 and 42. The edge connecting portions 401 of the two separators are relatively thick and not easily corroded or broken, while the connecting ring is relatively thin and easily corroded or broken. The specific structure is as follows:

[0052] refer to Figures 7 to 11 As shown, the main part 403 of the first partition 41 is connected to the edge connection part 401 of the first partition 41 through the first connecting ring 414. The thickness of the main part 403 and the edge connection part 401 of the first partition 41 is 10-15 mm, the thickness of the first connecting ring 414 is 4-6 mm, the diameter of the main part 403 of the first partition 41 is 120-140 mm (6-inch hot field), and the vertical height of the first raw material space 411 is 50-60 mm; the main part 403 of the second partition 42 is connected to the edge connection part 401 of the first partition 41 through the second connecting ring 424. The second partition 42 is connected to the edge connection part 401, the thickness of the main part 403 of the second partition 42 is 5-8mm, the thickness of the second connecting ring 424 is 2-3mm, the thickness of the edge connection part 401 of the second partition 42 is 10-15mm, the diameter of the main part 403 of the second partition 42 is 180-196mm (6-inch hot field), the vertical height of the second raw material space 421 is 10-15mm; the thickness of the third partition 43 is 10-15mm, and the vertical height of the third raw material space 431 is 10-15mm. Figure 9 As shown, the vent holes 40 are evenly distributed on the main part 403 of the first partition 41, the main part 403 of the second partition 42, the edge connection part 401 of the second partition 42 and the third partition 43. The diameter of the vent holes 40 is 2 mm. Figure 9 shown.

[0053] refer to Figure 10 and Figure 11As shown, during the crystal growth process, as the crystal growth time progresses, the first connecting ring 414 of the first partition 41 and the second connecting ring 424 of the second partition 42 corrode and eventually break, causing the main body components 403 of the first partition 41 and the second partition 42 to separate from the edge components and move downward. The silicon carbide powder on the upper portions of the main body components 403 of the two partitions also moves downward, preventing the formation of the ceramic body 70. Simultaneously, after the silicon carbide powder moves downward, it is closer to the high-temperature zone, which is conducive to the decomposition of the silicon carbide powder and improves the overall effective utilization rate of the silicon carbide powder. Furthermore, since the diameter of the main body component 403 of the first partition 41 is 120-140 mm, and the diameter of the main body component 403 of the second partition 42 is 180-196 mm, and only the main body components 403 move downward, the large-scale downward movement of the silicon carbide powder on the upper portions of the partitions is reduced, reducing the change in the temperature gradient within the crucible 20 caused by the change in the powder source position, avoiding the problem of carbon encapsulation caused by drastic changes, and improving the growth quality of the crystal.

[0054] Specifically, in Example 1, the diameter of the partition main body component 403 is relatively large. After the partition edge connection part 401 is broken, the partition main body component 403 and the powder above it move downward. The sudden break causes a large amount of powder to move downward instantly, which will cause drastic changes in the powder interior, thereby increasing the probability of carbon wrapping. In order to further reduce the problem of carbon encapsulation, considering the basic principle of induction heating, the temperature at the edge and bottom of the crucible 20 is higher, and the temperature at the upper center of the crucible 20 is lower. Therefore, the silicon carbide powder at the edge and bottom of the crucible 20 is closer to the high temperature zone of the thermal field. The decomposition efficiency of the silicon carbide powder in this area is higher and there is no need to move downward. The silicon carbide powder at the upper center of the crucible 20 is in the low temperature zone, that is, the high temperature zone, and needs to be moved downward to a position closer to the high temperature zone. On the one hand, it can avoid the formation of ceramic bodies, and on the other hand, it can improve the decomposition efficiency of silicon carbide powder, thereby increasing the growth rate of the crystal. Therefore, in this embodiment, only the diameter of the partition main body 403 in the lower area is set to be smaller than that in embodiment 1. After breaking, the silicon carbide powder above the main body 403 moves down to a position close to the high temperature zone. Since the amount of silicon carbide powder that moves down is relatively small, the impact on the inside of the powder is small, further avoiding the formation of carbon encapsulation, further improving the growth quality of the crystal, and at the same time avoiding the formation of ceramic bodies in the low temperature zone, thereby improving the powder source utilization rate.

[0055] Other components of the silicon carbide crystal growth thermal field structure according to the embodiment of the present invention, such as the crucible and the electromagnetic induction coil, and their operation are well known to those skilled in the art and will not be described in detail here.

[0056] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to 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 present invention 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 should not be understood as a limitation to the present invention.

[0057] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined.

[0058] In this utility model, unless otherwise expressly specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. For those skilled in the art, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0059] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0060] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0061] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and purpose of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A silicon carbide crystal growth thermal field structure, characterized in that: include Crucible; A partitioning member, comprising a plurality of partitions, each having a vent hole, and spaced apart from top to bottom within the crucible to define a plurality of raw material spaces within the crucible. The partitions from the bottommost layer to the second-topmost layer can break and sink after being corroded. The raw material spaces contain silicon carbide powder, and the closer the raw material space is to the crystal growth interface, the smaller the particle size and the higher the purity of the silicon carbide powder therein. An exhaust assembly, the exhaust assembly covering the upper portion of the crucible, wherein a seed crystal is mounted on the top wall of the exhaust assembly; A heat-insulating cylinder is wrapped around the outside of the crucible, and a set gap is formed between the heat-insulating cylinder and the top wall of the exhaust component.

2. The silicon carbide crystal growth thermal field structure according to claim 1, characterized in that: The exhaust assembly is an annular structure, and a connecting portion extends radially outward from the upper part of the exhaust assembly. The exhaust assembly is covered on the upper part of the crucible through the connecting portion, and the bottom of the exhaust assembly is in close contact with the upper surface of the top partition plate, and a certain gap is provided between the outer wall of the exhaust assembly and the inner wall of the crucible; the upper part of the exhaust assembly defines an annular groove for accommodating a graphite cover plate, and an annular graphite pressure plate is placed on the upper part of the graphite cover plate, the outer diameter of the annular graphite pressure plate is equal to the outer diameter of the graphite cover plate, and the width of the annular graphite pressure plate is the same as the width of the annular groove, the graphite cover plate is the top wall of the exhaust assembly, the seed crystal is mounted on the lower surface of the graphite cover plate, the top partition plate, the graphite cover plate and the inner wall of the exhaust assembly jointly define a growth space for crystal growth; exhaust holes are provided on the side walls of the exhaust assembly and the connecting portion.

3. The silicon carbide crystal growth thermal field structure according to claim 2, characterized in that: There are three partitions in total, including a first partition, a second partition and a third partition. The first partition, the second partition and the third partition are all circular structures. The first partition, the second partition and the third partition are installed in sequence from bottom to top inside the crucible. The first partition and the inner bottom wall and side wall of the crucible jointly define a first raw material space. The first partition, the second partition and the inner wall of the crucible jointly define a second raw material space. The second partition, the first partition and the inner wall of the crucible jointly define a third raw material space.

4. The silicon carbide crystal growth thermal field structure according to claim 3, characterized in that: The silicon carbide powder contained in the first raw material space has a particle size of 10-20 mesh and a purity of 99.999%; the silicon carbide powder contained in the second raw material space has a particle size of 30-40 mesh and a purity of 99.999%; the silicon carbide powder contained in the third raw material space has a particle size of 50-60 mesh and a purity of 99.999%; the silicon carbide powder above the third partition has a particle size of 80-100 mesh and a purity of 99.9999999%.

5. The silicon carbide crystal growth thermal field structure according to claim 3, characterized in that: The first partition plate and the second partition plate each include a main body component and an edge connection portion extending radially outward from the main body component.

6. The silicon carbide crystal growth thermal field structure according to claim 5, characterized in that: The main body of the first partition has a thickness of 10-15 mm, the edge connection portion has a thickness of 4-6 mm, and the vertical height of the first raw material space is 50-60 mm; The thickness of the main part of the second partition is 5-8 mm, the thickness of the edge connection part is 2-3 mm, and the vertical height of the second raw material space is 10-15 mm; The thickness of the third partition is 10-15 mm, and the vertical height of the third raw material space is 10-15 mm; The ventilation holes are evenly distributed on the first partition body component, the second partition component and the third partition, and the diameter of the ventilation holes is 2 mm.

7. The silicon carbide crystal growth thermal field structure according to claim 3, characterized in that: The first separator main body is connected to the first separator edge connection portion via a first connecting ring. The thickness of the first separator main body and the edge connection portion is 10-15 mm. The thickness of the first connecting ring is 4-6 mm. The diameter of the first separator main body is 120-140 mm (6-inch hot field). The vertical height of the first raw material space is 50-60 mm. The main body of the second separator is connected to the edge connection portion of the second separator through a second connecting ring. The thickness of the main body of the second separator is 5-8 mm, the thickness of the second connecting ring is 2-3 mm, the thickness of the edge connection portion of the second separator is 10-15 mm, the diameter of the main body of the second separator is 180-196 mm (6-inch hot field), and the vertical height of the second raw material space is 10-15 mm. The thickness of the third partition is 10-15 mm, and the vertical height of the third raw material space is 10-15 mm; The ventilation holes are evenly distributed on the first separator main body component, the second separator main body component, the second separator edge connecting portion and the third separator, and the diameter of the ventilation holes is 2 mm.

8. A silicon carbide crystal growth thermal field structure according to claim 6 or 7, characterized in that: It also includes a first mounting plate, a second mounting plate and a third mounting plate, the first mounting plate, the second mounting plate and the third mounting plate are all annular structures, the upper parts of the first mounting plate, the second mounting plate and the third mounting plate define annular grooves, the edge connecting parts of the first partition plate and the second partition plate and the outer bottom of the third partition plate are connected with mounting rings, the first partition plate, the second partition plate and the third partition plate are respectively connected to the first mounting plate, the second mounting plate and the third mounting plate through the cooperation of the mounting rings and the annular grooves, the first mounting plate, the second mounting plate and the third mounting plate are placed inside the crucible from bottom to top by mutual embedding, and are close to the inner wall of the crucible.

Images