A high-quality silicon carbide single crystal growth apparatus

Abstract

The utility model relates to silicon carbide single crystal growth technical field, concretely relates to a high quality silicon carbide single crystal growth device, including crucible body, the crucible cover body of buckling on the crucible body, be provided with seed crystal on the crucible cover body, be provided with the separation component in the crucible body, and the separation component is parallel to the bottom of the crucible body and sets up, the inner part of the crucible body is separated and forms two chambers of upper and lower, respectively is growth chamber and filler chamber, the filler chamber is paved with the powder layer required for crystal growth in, the powder layer includes silicon carbide powder layer and carbon powder layer, the carbon powder layer is paved in the upper of silicon carbide powder layer. The growth device can form the rich silicon atmosphere reaction through carbon powder layer and silicon carbide powder layer sublimation, significantly reduce the erosion of rich silicon atmosphere to the crucible, prolong the service life of the crucible, and avoid the formation recessed structure damage on the inner wall of the crucible, and then significantly reduce the probability of the appearance polytypoid structure transition, microtube and other defects in the crystal.

Description

Technical Field

[0001] This utility model relates to the field of silicon carbide single crystal growth and technology, and in particular to a high-quality silicon carbide single crystal growth device. Background Technology

[0002] Silicon carbide (SiC), as a third-generation wide-bandgap semiconductor material, has become an ideal choice for manufacturing high-temperature, high-frequency, high-power, and radiation-resistant electronic devices due to its superior properties. Physical vapor transport (PVT) is currently the mainstream method for growing SiC single crystals. However, this method still has a series of defects that affect the growth quality of SiC single crystals. Specifically, in the early stage of SiC single crystal growth, the gas phase component formed by the thermal decomposition and sublimation of SiC powder exhibits silicon-rich characteristics. This silicon-rich gas phase leads to excessively high silicon atmosphere partial pressure inside the crucible. Excessively high silicon atmosphere partial pressure will cause severe corrosion to the crucible, which will not only significantly shorten the service life of the crucible and limit its reuse, but also gradually form depressions on the inner wall of the crucible as corrosion continues, causing changes in the overall shape of the crucible. Even small changes in the shape of the crucible will disrupt the original temperature field balance, change the temperature field distribution, and induce defects such as polymorphic structural transformation and microtubes in the crystal, thereby reducing the growth quality and overall performance of SiC single crystals. In addition, in the early stage of single crystal growth, a large number of carbon particles generated will be transported to the growth surface, resulting in early carbon inclusions; in the middle and late stages of single crystal growth, the SiC powder in the crucible will be severely carbonized due to the rapid silicon sublimation. The carbonized silicon carbide material is easily transported to the growth surface with the atmosphere, resulting in middle and late stage carbon inclusions.

[0003] Patent application number 202211528490.3 discloses a silicon carbide crystal growth apparatus and its filling method. However, the growth apparatus cannot reduce or avoid the erosion of the crucible by the silicon-rich atmosphere, nor can it solve the problem of carbon inclusion defects caused by carbon particles and carbonized silicon carbide materials being transported to the growth surface with the gas phase components during single crystal growth.

[0004] This invention provides a high-quality silicon carbide single crystal growth device to solve the problems of existing devices being easily corroded, having a short service life, and having defects such as microtubes and carbon inclusions in the grown silicon carbide single crystals. Utility Model Content

[0005] The purpose of this invention is to provide a high-quality silicon carbide single crystal growth device to solve the problems of existing devices being easily corroded, having a short service life, and having defects such as microtubes and carbon inclusions in the grown silicon carbide single crystals.

[0006] The technical solution of this utility model is: a high-quality silicon carbide single crystal growth device, including a crucible body and a crucible cover fastened to the crucible body; a seed crystal is disposed on the crucible cover; a partition component is disposed inside the crucible body, and the partition component is disposed parallel to the bottom of the crucible body, dividing the interior of the crucible body into upper and lower chambers, which are a growth chamber and a filling chamber, respectively; a powder layer required for crystal growth is laid in the filling chamber, and the gas components formed by the sublimation of the powder layer under heat flow into the growth chamber after passing through the partition component to grow crystals;

[0007] The powder layer includes a silicon carbide powder layer and a carbon powder layer; the carbon powder layer is laid on top of the silicon carbide powder layer and is used to react with the silicon-rich atmosphere formed by the thermal sublimation of the silicon carbide powder layer.

[0008] Preferably, the packing cavity is provided with a porous graphite ring for filtering and optimizing the flow direction of gas components; the porous graphite ring is arranged parallel to the bottom of the crucible body and positioned below the carbon powder layer.

[0009] Preferably, the separating component includes a graphite ring and a porous graphite plate arranged coaxially; the outer side of the graphite ring abuts against the inner sidewall of the crucible body, and the inner side contacts the side of the porous graphite plate.

[0010] Preferably, the inner side of the graphite ring is provided with a protruding step; the porous graphite plate is placed on the step.

[0011] Preferably, there is a reserved space between the powder layer and the separating component for the diffusion and flow of gas components.

[0012] Preferably, the silicon carbide powder layer includes at least two layers, namely a first silicon carbide powder layer and a second silicon carbide powder layer laid on top of the first silicon carbide powder layer;

[0013] The particle size of the silicon carbide particles in the first silicon carbide powder layer is larger than the particle size of the silicon carbide particles in the second silicon carbide powder layer.

[0014] The porous graphite ring is positioned above the first silicon carbide powder.

[0015] Preferably, both the separator and the porous graphite ring are coated with a high-temperature resistant metal carbide coating or a metal nitride coating.

[0016] Compared with the prior art, the advantages of this utility model are:

[0017] (1) The present invention provides a high-quality silicon carbide single crystal growth device. This growth device can react with the silicon-rich atmosphere formed by the sublimation of carbon powder layer and silicon carbide powder layer, which can significantly reduce the erosion of the crucible body by the silicon-rich atmosphere, extend the service life of the crucible, and avoid structural damage such as the formation of depressions on the inner wall of the crucible body. This significantly reduces the probability of defects such as polymorphic structural transformation and microtubes in the crystal. It solves the problems of existing devices being easily eroded, having a short service life, and having defects such as microtubes and carbon inclusions in the grown silicon carbide single crystal. At the same time, this growth device can filter the gas components formed by the sublimation of powder at the bottom and side of the crucible body by heating through porous graphite rings, filter the gas components formed by the sublimation of the first silicon carbide powder layer by heating through the second silicon carbide powder layer, and filter the gas components flowing to the growth cavity through the separation component. This effectively reduces the number of carbon particles transported to the growth cavity, thereby significantly improving the growth quality of silicon carbide single crystal and reducing the number of carbon inclusions in the silicon carbide ingot. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0019] Figure 1 This is a schematic diagram of the structure of the high-quality silicon carbide single crystal growth apparatus described in this utility model;

[0020] Figure 2 This invention provides a simulation diagram of the graphitization state of the powder layer in the middle and late stages of an existing growth device.

[0021] Figure 3 The silicon carbide ingots obtained by this invention using the high-quality silicon carbide single crystal growth apparatus described above;

[0022] The components are: 1. Crucible body; 2. Crucible lid; 3. Seed crystal; 4. Separator assembly; 41. Graphite ring; 42. Porous graphite plate; 5. Filler cavity; 6. Growth cavity; 7. Powder layer; 71. Silicon carbide powder layer; 711. Silicon carbide powder layer; 712. Silicon carbide powder layer; 72. Carbon powder layer; 8. Porous graphite ring. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to specific embodiments:

[0024] A high-quality silicon carbide single crystal growth apparatus, such as Figure 1As shown, the system includes a crucible body 1 and a crucible cover 2. A seed crystal 3 is bonded to the inside of the crucible cover 2, which is then fastened to the crucible body 1, forming a relatively sealed and stable growth space. A partition component 4 is installed inside the crucible body 1. This partition component 4 is installed parallel to the bottom of the crucible body 1 and divides the interior of the crucible body 1 into upper and lower chambers: a filling chamber 5 located below the partition component 4 and a growth chamber 6 located above the partition component 4. This partition design effectively controls the flow of gas components and the reaction zone, creating more favorable environmental conditions for silicon carbide single crystal growth. The filling cavity 5 is filled with a powder layer 7 required for crystal growth. The gas components formed by the sublimation of these powder layers 7 under heat flow into the growth cavity 6 after passing through the separator 4 for crystal growth. The powder layer 7 includes a silicon carbide powder layer 71 and a carbon powder layer 72, with the carbon powder layer 72 laid on top of the silicon carbide powder layer 71. The main function of this laying method is to allow the silicon-rich atmosphere generated by the sublimation of the silicon carbide powder layer 71 to react with the carbon powder layer 72 laid on top during the heating process, thereby effectively adjusting the composition and ratio of the gas components and providing a stable gas source for the high-quality growth of silicon carbide single crystals. In addition, the reaction of the carbon powder layer 72 with the formed silicon-rich atmosphere can effectively reduce the corrosive effect of the silicon-rich atmosphere on the crucible body 1. This can not only extend the service life of the crucible, but also avoid structural damage such as depressions on the inner wall of the crucible body 1. This can significantly reduce defects such as polymorphic structural transformation and microtubes in the crystal, and improve the growth quality and overall performance of SiC single crystals.

[0025] In the middle and later stages of crystal growth, such as Figure 2 As shown, the darker areas indicate areas of severe graphitization. Based on the analysis of the graphitization state of silicon carbide powder during the simulation growth process, it is known that the graphitization of the powder at the bottom and sides of the crucible body 1 is more severe. To effectively avoid or minimize the undesirable situation where the carbonized silicon carbide material is transported to the growth surface by the atmosphere and forms carbon inclusions, a porous graphite ring 8 is provided in the filling cavity 5. This ring is used to filter the gas components formed by the thermal sublimation of the powder at the bottom and sides of the crucible body 1. Furthermore, the porous graphite ring 8 can optimize the flow direction of the gas components formed by the thermal sublimation of the powder at the bottom and sides of the crucible body 1, thereby ensuring the quality of crystal growth. The porous graphite ring 8 is positioned parallel to the bottom of the crucible body 1 below the carbon powder layer 72, and the outer surface of the porous graphite ring 8 abuts against the inner wall of the crucible body 1. The frictional force generated by this close contact keeps the porous graphite ring 8 in a fixed position throughout the crystal growth process.

[0026] The separating component 4 includes a graphite ring 41 and a porous graphite plate 42 arranged coaxially. The outer side of the graphite ring 41 abuts against the inner wall of the crucible body 1, and the inner side contacts the side of the porous graphite plate 42. During crystal growth, the gaseous components formed by the sublimation of the powder flow to the growth chamber 6 through the pores of the porous graphite plate 42. In this process, the porous graphite plate 42 acts as a filter for the gaseous components, effectively intercepting carbon particles in the gaseous components and preventing them from being transported to the growth chamber 6, thereby ensuring the purity of the crystal growth atmosphere. To ensure that the porous graphite plate 42 can be placed stably during crystal growth and to avoid shaking due to airflow impact, which would affect the filtration effect and crystal growth quality, a protruding step is provided on the inner side of the graphite ring 41. The porous graphite plate 42 is placed on this step, and the porous graphite plate 42 is stably fixed through the support and limiting effect of the step. In addition, there is a reserved space between the powder layer 7 and the separator 4, which provides the necessary space for the diffusion and flow of gas components, ensuring that the gas can flow smoothly into the growth chamber 6.

[0027] The silicon carbide powder layer 71 comprises at least two layers: a first silicon carbide powder layer 711 and a second silicon carbide powder layer 712 disposed on top of the first silicon carbide powder layer 711. The silicon carbide particles used in the first silicon carbide powder layer 711 have a larger particle size than those used in the second silicon carbide powder layer 712. The larger particle size of the silicon carbide particles causes the first silicon carbide powder layer 711 to exhibit higher porosity, while the second silicon carbide powder layer, composed of smaller particle size silicon carbide particles, exhibits higher porosity. The porosity of 712 is relatively low. In the thermal environment of crystal growth, the bottom of the crucible body 1 is in a high-temperature region, which allows the first silicon carbide powder layer 711 with a larger particle size at the bottom to be heated and sublimated immediately, generating corresponding gas components. When the gas components flow upward and pass through the second silicon carbide powder layer 712 with a smaller particle size, due to the pore structure characteristics of the second silicon carbide powder layer 712, it can filter some of the carbon particles in the gas components, thereby effectively reducing the number of carbon particles transported upward. The particle size of the first silicon carbide powder is preferably 700µm-2500µm, and the laying thickness is 30mm-60mm; the particle size of the second silicon carbide powder is preferably 300µm-700µm, and the laying thickness is 30mm-60mm; the carbon powder layer is made of carbon particles with a particle size of 30µm-150µm, and the laying thickness of the carbon powder layer is 5-20mm, most preferably 10-15mm.

[0028] Based on the thermal field distribution and particle generation, the porous graphite ring 8 is positioned above the first silicon carbide powder layer 711, that is, between the two layers of silicon carbide powder. Since the side wall at the bottom of the crucible body 1 is the area with the highest temperature in the entire thermal field, the number of graphitized particles generated here is the largest under these high temperature conditions. Placing the porous graphite ring 8 here can make full use of its porous structure, effectively filter out the carbonized particles in the gas composition, further optimize the crystal growth environment, and ensure the quality of crystal growth.

[0029] The surfaces of the aforementioned separator 4 and porous graphite ring 8 are coated with a high-temperature resistant rare metal carbide coating or a metal nitride coating to prevent gas components from corroding the separator 4 and porous graphite ring 8; and the rare metal is preferably tantalum, titanium, niobium, hafnium, tungsten, zirconium or vanadium; the porosity of the aforementioned porous graphite plate 42 and porous graphite ring 8 is preferably 30% to 80%.

[0030] Crystal growth is performed using the high-quality silicon carbide single crystal growth apparatus provided in this application, such as... Figure 3 As shown, high-quality silicon carbide ingots with almost no defects such as microtubes and carbon inclusions can be obtained.

[0031] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. It is obvious to those skilled in the art that this utility model is not limited to the details of the above exemplary embodiments, and that it can be implemented in other specific forms without departing from the spirit or basic characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this utility model is defined by the appended claims rather than the foregoing description, and therefore, all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within this utility model.

Claims

1. A high-quality silicon carbide single crystal growth apparatus, characterized in that, The system includes a crucible body (1) and a crucible cover (2) fastened to the crucible body (1); a seed crystal (3) is provided on the crucible cover (2); a partition component (4) is provided inside the crucible body (1), and the partition component (4) is arranged parallel to the bottom of the crucible body (1), dividing the interior of the crucible body (1) into upper and lower chambers, namely a growth chamber (6) and a filling chamber (5); a powder layer (7) required for crystal growth is laid in the filling chamber (5), and the gas components formed by the sublimation of the powder layer (7) under heat flow into the growth chamber (6) after passing through the partition component (4) to grow crystals; The powder layer (7) includes a silicon carbide powder layer (71) and a carbon powder layer (72); the carbon powder layer (72) is laid on top of the silicon carbide powder layer (71) and is used to react with the silicon-rich atmosphere formed by the thermal sublimation of the silicon carbide powder layer (71).

2. The high-quality silicon carbide single crystal growth apparatus according to claim 1, characterized in that: The packing cavity (5) is provided with a porous graphite ring (8) for filtering and optimizing the flow direction of gas components; the porous graphite ring (8) is arranged parallel to the bottom of the crucible body (1) and is located below the carbon powder layer (72).

3. The high-quality silicon carbide single crystal growth apparatus according to claim 2, characterized in that: The separating component (4) includes a graphite ring (41) and a porous graphite plate (42) arranged coaxially; the outer side of the graphite ring (41) abuts against the inner sidewall of the crucible body (1), and the inner side contacts the side of the porous graphite plate (42).

4. The high-quality silicon carbide single crystal growth apparatus according to claim 3, characterized in that: The graphite ring (41) has a protruding step on its inner side; the porous graphite plate (42) is placed on the step.

5. The high-quality silicon carbide single crystal growth apparatus according to claim 2, characterized in that: There is a reserved space between the powder layer (7) and the separator (4) for the diffusion and flow of gas components.

6. The high-quality silicon carbide single crystal growth apparatus according to claim 2, characterized in that: The silicon carbide powder layer (71) includes at least two layers, namely a first silicon carbide powder layer (711) and a second silicon carbide powder layer (712) laid on top of the first silicon carbide powder layer (711). The particle size of silicon carbide particles in the first silicon carbide powder layer (711) is larger than that of silicon carbide particles in the second silicon carbide powder layer (712). The porous graphite ring (8) is positioned above the first silicon carbide powder layer (711).

7. The high-quality silicon carbide single crystal growth apparatus according to claim 2, characterized in that: Both the separator (4) and the porous graphite ring (8) are coated with a high-temperature resistant metal carbide coating or a metal nitride coating.

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