Growth crucible, growth device and growth method of silicon carbide crystals

Abstract

The invention relates to the technical field of silicon carbide crystal growth, and particularly provides a growth crucible, a growth device and a growth method of silicon carbide crystals. The growth crucible comprises a body part, a covering part and a flow guide part; wherein the flow guide part is arranged between the body part and the covering part; the flow guide part is of an annular structure and comprises a first surface, a second surface and a plurality of flow guide holes, wherein the first surface and the second surface are oppositely arranged, and the flow guide holes communicate with the first surface and the second surface. The orthographic projections of the first opening and the second opening of the flow guide hole on the second surface are at least partially not overlapped, the first opening is the opening of the flow guide hole on the first surface, and the second opening is the opening of the flow guide hole on the second surface. By arranging the annular flow guide part with the inclined flow guide holes, sublimation gas can be effectively guided to form an ordered flow path, vortex generation is reduced, gas concentration distribution uniformity is improved, and the crystal growth device has the advantages of improving crystal growth interface stability and crystal quality.

Description

Technical Field

[0001] This application relates to the field of silicon carbide crystal growth technology, and in particular to a growth crucible, growth apparatus and growth method for silicon carbide crystals. Background Technology

[0002] Silicon carbide (SiC), a typical binary compound semiconductor material, has become a core material in the field of wide-bandgap semiconductors due to its excellent comprehensive performance. Its physical properties are outstanding, with a Mohs hardness of 9.5, second only to diamond, and excellent thermal conductivity. A typical crystal form, represented by 4H-SiC, has a bandgap of 3.2 eV. Semiconductor devices based on this material exhibit significant advantages such as low leakage current and high breakdown electric field, making it an ideal core material for high-power electronic devices. Furthermore, its saturated electron mobility is 2-3 times higher than that of traditional silicon materials, demonstrating irreplaceable application potential in the field of high-frequency devices.

[0003] However, the growth of silicon carbide crystals faces significant technical challenges. Despite its thermodynamic stability and high melting point, silicon carbide decomposes directly into silicon vapor and carbon vapor under normal pressure and high temperature conditions, a characteristic that limits the application of traditional crystal growth methods. Currently, the physical vapor transport (PVT) method is the industry-recognized mainstream technology for silicon carbide single crystal growth. In the process of growing 4H-SiC single crystals using the PVT method, seed crystal temperature control, saturated vapor pressure control, optimization of silicon carbide sublimation rate, and the distribution and flow state of sublimation gas are the key factors determining crystal quality (such as defect density and uniformity) and growth rate.

[0004] In existing technologies, the flow state of the mixed gas generated during silicon carbide sublimation within the growth furnace cavity is significantly inadequate. The flow is not ideal—uniform, linear, and uniformly upward—but rather tends to form vortex-like flows. This non-ideal flow state leads to uneven gas concentration distribution and disordered transport paths within the furnace cavity, resulting in problems such as unstable crystal growth interfaces and poor doping uniformity, severely restricting the efficient preparation of high-quality silicon carbide single crystals. Summary of the Invention

[0005] The main objective of this application is to provide a growth crucible, growth apparatus, and growth method for silicon carbide, aiming to solve the technical problem that the uneven flow state of the mixed gas generated by silicon carbide sublimation in the growth furnace cavity leads to uneven gas concentration distribution and disordered transport path in the furnace cavity, which in turn causes unstable crystal growth interface and poor doping uniformity.

[0006] To achieve the above objectives, in a first aspect, this application provides a growth crucible for silicon carbide, comprising: a body portion, a cover portion, and a flow guiding portion; wherein, a receiving cavity with an opening is formed inside the body portion; the cover portion is disposed at one end of the body portion near the opening of the receiving cavity; A flow guide is disposed between the main body and the cover; wherein the flow guide is an annular structure, the flow guide includes a first surface and a second surface disposed opposite to each other and a plurality of flow guide holes connecting the first surface and the second surface; the orthographic projections of the first opening and the second opening of the flow guide holes on the second surface do not overlap at least partially, the first opening is the opening of the flow guide hole on the first surface, and the second opening is the opening of the flow guide hole on the second surface; the orthographic projections of each flow guide hole intersect at least in pairs.

[0007] Optionally, the extension lines of each of the flow guide holes located on one side of the first surface have at least two points of intersection.

[0008] Optionally, the cross-sectional shape of the guide hole along the direction perpendicular to the first surface is a parallelogram.

[0009] Optionally, one interior angle of the parallelogram is α, where 15°≤α≤75°.

[0010] Optionally, the receiving cavity has a protrusion on the inner wall surface near the cover, and the protrusion is a continuous annular structure or an intermittent annular structure.

[0011] Optionally, the body, the cover, and the flow guide are all made of graphite.

[0012] Optionally, the cover includes: The crucible lid has an internal cavity with an opening, the opening of which is positioned opposite to the opening of the receiving cavity; A growth plate, located within the cavity, is used to hold seed crystals.

[0013] Optionally, the end face of the crucible cover away from the main body is provided with a plurality of through holes, and the plurality of through holes communicate with the cavity.

[0014] Secondly, this application provides a silicon carbide crystal growth apparatus, comprising: The growth crucible described in any of the first aspects above; A heating device is located at the bottom of the growth crucible.

[0015] Thirdly, this application provides a method for growing silicon carbide crystals, implemented based on the silicon carbide crystal growth apparatus described in the third aspect above, the method comprising: 4H-SiC was selected as the seed crystal, and the seed crystal was fixed on the surface of the growth plate near the body. The silicon carbide raw material is placed into the receiving cavity, and the body, cover and guide parts are assembled. The silicon carbide crystal growth apparatus is heated using a heating device, and the temperature near the growth plate is controlled to be greater than or equal to 2130°C and less than or equal to 2200°C, and the pressure between the containment cavity and the cavity body is controlled to be greater than or equal to 500Pa and less than or equal to 1000Pa.

[0016] This application discloses a silicon carbide crystal growth crucible, growth apparatus, and growth method. A flow guide is disposed between the body and the cover; the flow guide is annular and includes a first surface and a second surface disposed opposite to each other, and a plurality of flow guide holes connecting the first and second surfaces; the orthographic projections of the first and second openings of the flow guide holes do not overlap at least partially, with the first opening being the opening of the flow guide hole on the first surface and the second opening being the opening of the flow guide hole on the second surface. That is, by providing an annular flow guide with inclined flow guide holes, sublimation gas can be effectively guided to form an orderly flow path, reducing eddy current generation, thereby improving the uniformity of gas concentration distribution and having the advantages of improving the stability of the crystal growth interface and the crystal quality.

[0017] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 A cross-sectional view of a silicon carbide crystal growth crucible provided for this application; Figure 2 for Figure 1 Top view of the guide section provided in the image; Figure 3 for Figure 1 The cross-sectional view of the guide section provided in the image; Figure 4 for Figure 1 A schematic diagram of the structure of one embodiment of the protrusion provided in the diagram; Figure 5 for Figure 4 A schematic diagram of another embodiment of the protrusion provided in the diagram; Figure 6 A top view of the crucible lid provided in an embodiment of this application; Figure 7 A cross-sectional view of the silicon carbide crystal growth apparatus provided in an embodiment of this application.

[0020] Figure label: 1. Main body; 11. Receiving cavity; 111. Protrusion; 2. Cover; 21. Crucible lid; 211. Cavity; 212. Through hole; 22. Growth plate; 221. Seed crystal; 3. Flow guide section; 31. First surface; 32. Second surface; 33. Flow guide hole; 331. First opening; 332. Second opening; 4. Heating device.

[0021] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0023] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0024] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0025] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0026] In existing technologies, during the growth of silicon carbide crystals, sublimated gas easily forms vortex-like flows within the furnace cavity, leading to uneven gas concentration distribution and disordered transport paths. This results in problems such as unstable crystal growth interfaces and poor doping uniformity. Although traditional physical vapor transport methods are the mainstream technology, there are still significant shortcomings in the control of gas flow states, which restricts the efficient preparation of high-quality crystals.

[0027] To address the aforementioned problems, the inventors discovered that optimizing the gas flow path is key to improving crystal quality. Analysis of the eddy formation mechanism revealed that straight flow paths easily lead to energy accumulation, resulting in turbulent gas flow. Therefore, a structure capable of altering the gas transport direction is needed to disperse flow energy and suppress eddy formation. Based on this idea, the inventors proposed incorporating a component with a special flow-guiding structure inside the crucible, achieving airflow direction control through an asymmetric channel layout.

[0028] Figure 1 A cross-sectional view of a silicon carbide crystal growth crucible provided in this application. Figure 2 for Figure 1 The top view of the guide section provided in the image. Figure 3 for Figure 1 The cross-sectional diagram of the guide section provided in the document. Figure 4 for Figure 1 A schematic diagram of one embodiment of the protrusion provided in the diagram. Figure 5 for Figure 4 A schematic diagram of another embodiment of the protrusion provided in the diagram. Figure 6 This is a top view of the crucible lid provided in an embodiment of this application. Figure 7 A cross-sectional view of the silicon carbide crystal growth apparatus provided in an embodiment of this application.

[0029] like Figure 1 , Figure 2 and Figure 3As shown in the embodiment of this application, a growth crucible for silicon carbide crystals is proposed. The growth crucible includes: a body part 1, a cover part 2, and a flow guiding part 3. The body part 1 has an opening in the cavity 11. The cover part 2 is located at one end of the body part 1 near the opening of the cavity 11. The flow guiding part 3 is located between the body part 1 and the cover part 2. The flow guiding part 3 has an annular structure and includes a first surface 31 and a second surface 32 disposed opposite to each other, and a plurality of flow guiding holes 33 connecting the first surface 31 and the second surface 32. The first opening 331 and the second opening 332 of the flow guiding holes 33 do not overlap at least partially in their orthographic projections on the second surface 32. The first opening 331 is the opening of the flow guiding hole 33 on the first surface 31, and the second opening 332 is the opening of the flow guiding hole 33 on the second surface 32.

[0030] The main body 1 refers to the main structure that carries the raw materials. Its receiving cavity 11 is used to place the silicon carbide raw material 112, which can be implemented using a cylindrical or conical container structure to form a closed growth space. The cover 2 refers to the component that covers the opening of the main body 1, which can be implemented using a split sealing structure, and cooperates with the main body 1 to form a closed cavity 211. The flow guide 3 refers to the annular structure set in the middle section of the crucible, which can be implemented using graphite to form a perforated annular ring, used to guide the gas flow direction. The flow guide hole 33 refers to the channel that penetrates the upper and lower surfaces of the flow guide 3. The projection of its first opening 331 and second opening 332 is misaligned, which can be implemented using an inclined through hole or stepped hole structure, forcing the gas to change its flow direction when passing through.

[0031] Furthermore, the extension lines of each guide hole 33 located on one side of the first surface 31 have at least two points of intersection.

[0032] Specifically, when the gas flows upward from the main body 1, it first enters the first opening 331 of the guide hole 33 in the guide section 3. Because the first opening 331 and the second opening 332 of the guide hole 33 are misaligned in their projection positions on the second surface 32, the gas is forced to deflect when passing through the guide hole 33. The inclined guide hole 33 guides the originally spiraling upward airflow, causing the gas to flow along the inclined channel, changing the flow direction of the gas, thereby making the gas rise uniformly and suppressing the formation of eddies.

[0033] Furthermore, since the extension lines of adjacent guide holes 33 on one side of the first surface 31 intersect, that is, the first openings 331 of adjacent guide holes 33 form airflow convergence points in the region of the first surface 31, the airflows from different channels collide with each other here, further dispersing the kinetic energy of the gas flow. The annular guide structure makes the gas evenly distributed along the circumference, avoiding local velocity differences. Through the synergistic effect of multiple channels, the originally linearly rising airflow is decomposed into multiple controllable branch flows, effectively suppressing the formation of vortices.

[0034] This design, through the staggered arrangement of the guide holes 33, enables controllable changes in gas flow direction during transmission, disrupting the conditions for vortex generation. Existing technologies with uniformly arranged vertical channels can only achieve simple flow splitting, while the inclined channel design of this design generates three-dimensional airflow interference, significantly improving flow uniformity.

[0035] Through the above technical solution, this application effectively improves the flow state of sublimation gas, reduces the occurrence of eddy currents, and makes the gas distribution at the growth interface more uniform. The temperature gradient stability at the crystal growth interface is improved, and the transport path of the raw material vapor is more controllable, thereby reducing the crystal defect density and improving doping uniformity and crystal growth quality.

[0036] like Figure 3 As shown in the exemplary embodiment, the present application further proposes that the cross-sectional shape of the guide hole 33 along the direction perpendicular to the first surface 31 is a parallelogram.

[0037] The parallelogram cross-section refers to the closed geometric shape of the flow hole 33 in the direction perpendicular to the first surface 31, where all four sides are straight line segments. This can be achieved through machining or mold forming, resulting in symmetrical or asymmetrical inclination angles on both sides of the flow hole. The interior angle α of the parallelogram refers to an interior angle less than 90°, which can be achieved using an angle value within the range of 15° to 75°. The degree of inclination of the flow hole is controlled by adjusting the size of the acute angle.

[0038] Specifically, the guide hole 33 forms an inclined channel structure with a parallelogram cross-section, and its two side walls are asymmetrically distributed relative to the first surface 31 and the second surface 32. When the sublimated gas flows through the guide hole 33, the geometry of the inclined channel forces the gas to deflect during the flow. The presence of acute angles creates a clear guiding surface on the channel wall, and gas molecules change their trajectory along a preset angle after colliding with the wall. This directional guidance effect can suppress disordered gas diffusion, allowing the airflow to form a stable laminar flow state after passing through the guide hole 33, thereby reducing the generation of local eddies.

[0039] This scheme uses an inclined channel design with a parallelogram cross-section to geometrically constrain the gas during transport, forcing it to flow in a specific direction. This alters the dynamic characteristics of the gas flow and fundamentally optimizes the airflow distribution pattern.

[0040] Through the above technical solution, this application can effectively guide the sublimation gas to form directional laminar flow, reduce the degree of flow path turbulence, and make the gas uniformly distributed at the crystal growth interface, thereby improving the stability of the crystal growth interface and reducing the crystal defect density.

[0041] Please continue reading. Figure 3 In an exemplary embodiment, optionally, one interior angle of the parallelogram is α, where 15°≤α≤75°.

[0042] Here, an interior angle α of the parallelogram refers to an interior angle of the parallelogram that is less than 90°. Specifically, it can be achieved using an angle value within the range of 15° to 75°. The inclination of the channel is controlled by adjusting the size of the acute angle. This angle range is used to adjust the gas flow direction by limiting the inclination of the guide hole 33 wall. The range of 15° to 75° is a boundary condition set based on gas dynamics characteristics. When the angle is less than 15°, an excessively large inclination of the guide hole 33 wall will cause excessive deflection of the gas flow path, while when the angle is greater than 75°, an excessively small inclination of the guide hole 33 wall will result in insufficient gas flow direction adjustment capability.

[0043] Specifically, when the cross-section of the guide hole 33 adopts a parallelogram structure, its acute angle is controlled between 15° and 75°. Within this range, the inclination angle of the guide hole 33 wall can form an effective gas guiding channel while avoiding sudden changes in flow resistance due to an excessively small angle or turbulence effects caused by an excessively large angle. For example, when the acute angle is set to 30 degrees, the guide hole 33 wall forms a moderately inclined channel, causing uniform deflection flow when the gas passes through; when the acute angle is set to 60 degrees, the inclination of the guide hole 33 wall decreases but still maintains the ability to control the gas flow direction. This selection of angle range allows the gas to form a stable laminar flow state when flowing through the guide hole 33, while multi-directional diffusion of the gas within the crucible is achieved through combinations of guide holes 33 with different angles.

[0044] This solution limits the acute angle range of the cross-section of the guide hole 33, enabling a controllable deflection effect of the gas as it passes through the guide hole 33. This avoids uneven concentration gradients caused by an overly straight flow path and prevents flow separation caused by excessively large angles. It should be noted that the parallelogram cross-sectional shape of the guide hole 33 in this embodiment is merely an exemplary example. This application does not specifically limit the cross-sectional shape of the guide hole 33, as long as the orthographic projections of the first opening 331 and the second opening 332 of the guide hole 33 do not at least partially overlap.

[0045] Through the above technical solution, this application effectively improves the uniformity of sublimation gas distribution during silicon carbide crystal growth, making the gas flow path more stable and controllable, thereby reducing concentration fluctuations at the crystal growth interface and improving the integrity and doping uniformity of the crystal structure. The optimized design of the acute angle parameters of the flow guide hole 33 maintains gas transport efficiency while suppressing the impact of non-ideal flow states on crystal growth quality.

[0046] like Figure 4 and Figure 5As shown, in an exemplary embodiment, the receiving cavity 11 has a protrusion 111 on the inner wall surface near the cover 2, and the protrusion 111 has a continuous annular structure.

[0047] Optionally, the inner wall surface of the receiving cavity 11 near the cover 2 is provided with a protrusion 111, and the protrusion 111 has an intermittent annular structure.

[0048] The protrusion 111 refers to a physical blocking structure extending from the inner wall of the receiving cavity 11 towards the interior of the cavity 211. Specifically, it can be formed into a ring-shaped protrusion on the inner wall of the crucible using machining or molding processes, providing an installation position for the guide section 3 (graphite ring). For example... Figure 4 As shown, a continuous annular structure refers to a closed annular protrusion without interruption along the circumference of the inner wall. Specifically, it can be formed by machining annular flanges of uniform height. For example... Figure 5 As shown, the discontinuous ring structure refers to multiple independent protruding units distributed circumferentially along the inner wall. Specifically, the discretely distributed protrusions can be formed by drilling or milling processes.

[0049] In some embodiments, the body 1, the cover 2, and the guide 3 are all made of graphite.

[0050] Graphite material refers to a crystalline material composed of carbon elements, specifically high-purity isostatically pressed graphite, whose layered crystal structure endows the material with anisotropic thermal conductivity. The body part 1 refers to the component constituting the main structure of the crucible, specifically formed by processing a cylindrical graphite block, with its internal receiving cavity 11 for loading silicon carbide raw material 112. The cover part 2 is a structural component that seals the opening of the receiving cavity 11, specifically implemented as a graphite cover with through holes 212, used to establish a gaseous substance transport channel. The flow guiding part 3 is a functional component that regulates the gas flow path, specifically implemented as a porous graphite ring structure, with the geometric arrangement of its flow guiding holes 33 determining the gas transport direction.

[0051] Specifically, in a high-temperature growth environment, the high thermal conductivity of graphite allows heat to diffuse uniformly along the axial direction of the main body 1, preventing excessive temperature differences between the bottom and top of the receiving cavity 11. When the flow guide 3, main body 1, and cover 2 are made of the same material, the consistency of their thermal expansion coefficients eliminates interfacial thermal stress, preventing deformation or misalignment of the flow guide 33 during thermal cycling. Graphite's high-temperature resistance ensures that the flow guide 33 maintains its preset geometric shape at 2200 degrees Celsius, ensuring the directional flow of silicon carbide vapor along the inclined channels. Graphite's chemical stability prevents it from reacting with silicon vapor to form silicon carbide deposits, maintaining the unobstructed flow of the flow guide 33.

[0052] Compared to existing technologies, traditional crucibles using a combination of different materials, such as metal and ceramic components, suffer from cracks at the interface due to differences in thermal expansion coefficients, leading to gas leakage or flow path deviation at high temperatures. In contrast, crucible assemblies made from a single graphite material expand and contract synchronously with temperature changes, maintaining the positional accuracy of the flow guide holes 33. Compared to improved solutions that use graphite coatings only in specific areas of the flow guide section 3, the overall graphite structure eliminates the risk of coating peeling, ensuring long-term reliability.

[0053] Through the above technical solutions, this application achieves a uniform distribution of the internal thermal field of the crucible, keeping the transmission speed of silicon carbide vapor in the guide hole 33 stable; maintaining the geometric accuracy of the guide hole 33 structure, avoiding the deviation of the gas flow path due to material deformation; preventing the contamination of the crystal growth environment by material deterioration under high temperature conditions, ensuring the chemical purity of silicon carbide single crystal; reducing the risk of structural failure during repeated heating and cooling, and extending the service life of the crucible.

[0054] like Figure 1 and Figure 6 As shown in the exemplary embodiment, this application further proposes a structural scheme including a crucible cover 21 and a growth plate 22. The crucible cover 21 forms a cavity 211 with an opening inside, and the opening of the cavity 211 is disposed opposite to the opening of the receiving cavity 11. The growth plate 22 is disposed inside the cavity 211 for placing seed crystals 221.

[0055] The crucible lid 21 is a covering component with a specific cavity structure. Specifically, it can be made of graphite material to form a container structure with symmetrical openings. The alignment of the openings of the cavity 211 and the receiving cavity 11 forms a continuous sealed space, enabling directional control of the gas phase transport path. The growth plate 22 is an independent component that supports the seed crystal 221. Specifically, it can be a flat graphite plate fixed inside the cavity 211. Physical isolation prevents material migration between the seed crystal 221 and the crucible lid 21 under high-temperature conditions, while providing a stable supporting plane for crystal growth.

[0056] Specifically, the opening of the cavity 211 of the crucible lid 21 and the opening of the receiving cavity 11 of the main body 1 form a symmetrical layout, allowing the sublimation gas to maintain axial flow during transport. The growth plate 22 is fixed at a specific position inside the cavity 211, and the seed crystal 221 is precisely placed in the thermal equilibrium region at the end of the gas transport path. The symmetrical opening structure of the cavity 211 and the receiving cavity 11 forms a continuous channel, enabling the gas to complete directional transport within the sealed space. The physical isolation design between the growth plate 22 and the crucible lid 21 effectively prevents the contact reaction between the graphite material and the seed crystal 221 under high temperature conditions while maintaining the mechanical stability of the seed crystal 221.

[0057] This scheme constructs a symmetrically opened, sealed cavity 211 to create a stable laminar flow state for the gas during transport, preventing the generation of eddies. An independent growth plate structure 22 is employed to achieve physical isolation while ensuring support strength.

[0058] Through the above technical solutions, this application achieves precise positioning of the seed crystal 221 in the optimal thermodynamic region, ensuring the axial stability of the gas transport path and avoiding the interpenetration of heterogeneous materials under high-temperature conditions. The sublimated gas forms a uniform diffusion within the symmetrical cavity 211 structure, effectively controlling the material deposition rate at the crystal growth interface. The independent setting of the growth plate 22 blocks the migration path of graphite material to the seed crystal 221, reducing the probability of internal crystal defects.

[0059] In some embodiments, the end face of the crucible cover 21 away from the body part 1 is provided with a plurality of through holes 212, and the plurality of through holes 212 communicate with the cavity 211.

[0060] The through-hole 212 refers to a through-hole structure formed on the end face of the crucible lid 21. It can be achieved through mechanical drilling or laser processing, and the diameter of the hole can be adjusted according to the gas flow requirements. The through-hole 212 facilitates the operator's manual opening of the crucible lid 21. The cavity 211 refers to the hollow structure formed inside the crucible lid 21, which provides space for the installation of the growth plate 22. Its volume matches the space requirements of the seed crystal 221 growth area.

[0061] like Figure 7 As shown in the illustration, this application also provides a silicon carbide crystal growth apparatus. This growth apparatus includes a silicon carbide crystal growth crucible provided in any of the above embodiments and a heating device 4 disposed at the bottom of the growth crucible.

[0062] The silicon carbide crystal growth crucible refers to a sealed container structure comprising a body 1, a cover 2, and a flow guide 3. The flow guide 3 is designed as an annular component with asymmetric flow guide holes 33. Specifically, it can be made of graphite material to form an annular partition. The inlet and outlet projection positions of the flow guide holes 33 are at least partially misaligned, guiding the gas through inclined channels to form a uniform upward path. The heating device 4 refers to the energy supply unit located at the bottom of the crucible. Specifically, it can be a resistance heater or an induction coil. A bottom-up temperature gradient is formed through the bottom heat source, causing the mixed gas generated by the sublimation of the raw materials to be directionally transported under thermal convection.

[0063] Specifically, the flow guide section 3 of the growth crucible optimizes the gas flow path through the geometric arrangement of the flow guide holes 33. The projected misalignment design of the inlet and outlet of the flow guide holes 33 generates a tangential velocity component when the gas passes through, suppressing eddy formation. The thermal field distribution of the bottom heating device 4 and the spatial position of the flow guide holes 33 work synergistically to control the gas diffusion rate and direction through a temperature gradient. During crystal growth, the mixed gas generated by the sublimation of the raw materials is guided by the flow guide holes 33 to form a laminar flow, while the bottom heat source maintains a stable thermal convection effect, matching the gas phase transport path with the temperature field distribution, thereby reducing concentration fluctuations and stabilizing the crystal growth interface.

[0064] This solution actively regulates the gas flow pattern and thermal field distribution through the combined design of the flow guide hole 33 structure and the bottom heating device 4, so that the gas transmission path and temperature gradient form a spatial coupling, thus solving the crystal defect problem caused by flow turbulence in traditional methods.

[0065] Through the above technical solution, this application achieves directional control of the gas flow state during silicon carbide crystal growth, effectively reducing the randomness of the gas phase transport path and maintaining a stable material supply at the crystal growth interface. Simultaneously, the temperature gradient formed by the bottom heating device 4, in synergy with the flow guide hole 33 structure, suppresses local overheating or overcooling, improving the uniformity of crystal doping and the consistency of growth rate.

[0066] This application embodiment also provides a growth method based on a silicon carbide crystal growth apparatus. The growth method includes the following steps: selecting 4H-SiC as a seed crystal 221 and fixing it on the surface of the growth plate 22 near the body part 1; placing the silicon carbide raw material 112 into the receiving cavity 11 and completing the assembly of the body part 1, the cover part 2, and the guide part 3; heating by a heating device 4, and controlling the temperature near the growth plate 22 to be greater than or equal to 2130°C and less than or equal to 2200°C, and controlling the pressure between the receiving cavity 11 and the cavity 211 to be greater than or equal to 500Pa and less than or equal to 1000Pa (that is, controlling the growth interface temperature of the seed crystal 221 to be in the range of 2130°C–2200°C, and controlling the furnace pressure to be in the range of 500Pa–1000Pa).

[0067] Among these, the seed crystal 221 growth interface temperature control refers to maintaining the temperature balance in the contact area between the seed crystal 221 and the raw material sublimation gas. This can be achieved using a multi-stage temperature control system combined with real-time temperature feedback adjustment, ensuring sufficient sublimation of the raw material while avoiding thermal damage to the seed crystal 221. The furnace pressure control refers to adjusting the pressure of the gas environment inside the growth device. This can be achieved through the coordinated operation of a vacuum pump and an inert gas injection system, suppressing turbulence by reducing gas phase transport resistance. The flow guide 3 assembly refers to installing a structure with flow guide holes 33 between the main body 1 and the cover 2. This can be achieved through tenon and mortise joints between graphite components to achieve a sealed connection, utilizing the spatial distribution of the flow guide holes 33 to guide the gas into an orderly flow path.

[0068] Specifically, during the seed crystal 221 fixing stage, by attaching the 4H-SiC seed crystal 221 to the surface of the growth plate 22 near the raw material area, the sublimation gas transport distance is shortened and the lattice matching is enhanced. During the assembly stage, the annular structure of the flow guide 3 and its flow guide holes 33, through their tilted opening design, cause directional deflection of the gas as it passes through, suppressing eddy formation. During the heating stage, when the temperature is controlled within the range of 2130°C–2200°C, the sublimation rate of the silicon carbide raw material 112 and the deposition rate on the surface of the seed crystal 221 reach a dynamic equilibrium. Meanwhile, the furnace pressure range of 500Pa–1000Pa reduces the probability of collisions between gas molecules, promoting the directional migration of gaseous components along the path defined by the flow guide holes 33. The synergistic effect of temperature and pressure forms a stable supersaturation gradient, enabling uniform deposition of gas molecules at the seed crystal 221 interface.

[0069] In some exemplary embodiments, the seed crystal 221 can be fixed using a high-temperature adhesive, such as graphite adhesive, to bond the seed crystal 221 to the surface of the growth plate 22. Temperature control can be achieved by arranging thermocouples in different areas of the furnace, for example, setting temperature measuring points in the raw material area and the seed crystal 221 area respectively, and adjusting the heating power through a PID algorithm. Pressure control can adopt a dynamic balance mode, for example, starting a vacuum pump to evacuate gas when the furnace pressure exceeds a set threshold, and injecting argon gas to maintain stability when the pressure is below the lower limit.

[0070] This scheme, through the spatial arrangement of the guide holes 33 combined with precise temperature and pressure control, enables the sublimation gas to form a linear flow path, effectively eliminating eddy currents. Simultaneously, the combination of a specific temperature range and a low-pressure environment ensures complete sublimation of the raw materials while reducing energy loss during gas phase transport. Compared to conventional processes that rely solely on temperature or pressure regulation, this significantly improves crystal growth stability.

[0071] Through the above technical solution, this application solves the problem of growth interface fluctuation caused by gas flow turbulence during silicon carbide crystal growth. By forming an ordered gas flow path, the gas phase components are uniformly deposited on the surface of the seed crystal 221, improving the integrity of the crystal structure. At the same time, precise control of temperature and pressure optimizes the utilization rate of raw materials, shortens the crystal growth cycle, and realizes the efficient preparation of 4H-SiC single crystals.

[0072] This application further proposes a method for growing silicon carbide crystals, including selecting 4H-SiC as a seed crystal 221 and fixing the seed crystal 221 on the surface of the growth plate 22 near the body part 1; placing the silicon carbide raw material 112 into the receiving cavity 11 and assembling the body part 1, the cover part 2 and the guide part 3; heating the growth device using a heating device 4, controlling the growth interface temperature of the seed crystal 221 within the range of 2130°C–2200°C, and controlling the furnace pressure within the range of 500Pa–1000Pa.

[0073] The fixed position of the seed crystal 221 refers to the tight bonding of the seed crystal 221 to the contact surface of the growth plate 22 using mechanical clamps or high-temperature adhesives, ensuring a constant relative position between the crystal growth interface and the raw material sublimation area. The temperature control range refers to the real-time monitoring of the surface temperature of the seed crystal 221 using thermocouples or infrared temperature measuring devices, combined with power adjustment of the heating device 4 to achieve closed-loop temperature control. This range balances the silicon carbide sublimation rate and crystal growth stability. The pressure control range refers to the dynamic adjustment of the gas pressure inside the furnace using a vacuum pump group and an inert gas injection system, employing a pressure sensor and a proportional-integral-differential algorithm to achieve pressure stability. This range suppresses disordered gas flow and optimizes the transmission path.

[0074] Specifically, after the seed crystal 221 is fixed, a closed growth environment is formed through assembly. During the heating process, the silicon carbide raw material 112 sublimates into a gaseous substance within the receiving cavity 11. When the temperature is controlled within the range of 2130°C–2200°C, the raw material fully sublimates but does not reach the critical decomposition temperature, and the gaseous substance forms a directional flow through the guide holes 33. When the pressure is maintained at 500Pa–1000Pa, the mean free path of the gas molecules is shortened, and the flow direction is guided by the geometry of the guide holes 33, reducing turbulence. When the gaseous substance is deposited on the surface of the seed crystal 221, the stable temperature gradient and pressure gradient work together to maintain a planar advancement mode at the crystal growth interface, avoiding lattice defects caused by local overcooling or overheating.

[0075] This method transforms disordered eddies into laminar flow by limiting the temperature and pressure parameter ranges and combining this with the gas distribution optimization function of the flow guide structure. The doping inhomogeneity problem caused by gas concentration fluctuations in existing technologies is improved in this scheme by stabilizing the transport path, allowing the crystal growth interface to maintain continuous expansion.

[0076] Through the above technical solution, this application achieves directional transport of gaseous substances during silicon carbide crystal growth, effectively suppressing crystal interface fluctuations caused by gas flow turbulence. The improved stability of the temperature gradient at the crystal growth interface leads to a more uniform deposition rate of silicon carbide molecules on the seed crystal 221 surface, reducing the defect density within the crystal. The synergistic effect of furnace pressure and the flow guiding structure reduces the randomness of the gas transport path, improving the uniformity of dopant element distribution in the crystal.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A silicon carbide crystal growth crucible, characterized in that, include: The main body (1) has an opening in the cavity (11) inside. A cover (2) is provided at one end of the main body (1) near the opening of the receiving cavity (11); A flow guide (3) is provided between the main body (1) and the cover (2); The flow guide (3) is an annular structure, and the flow guide (3) includes a first surface (31) and a second surface (32) disposed opposite to each other, and a plurality of flow guide holes (33) connecting the first surface (31) and the second surface (32). The first opening (331) and the second opening (332) of the flow guide hole (33) do not overlap at least partially on the orthographic projection of the second surface (32). The first opening (331) is the opening of the flow guide hole (33) on the first surface (31), and the second opening (332) is the opening of the flow guide hole (33) on the second surface (32).

2. The silicon carbide crystal growth crucible according to claim 1, characterized in that, The extension lines of each of the flow guide holes (33) located on one side of the first surface (31) have at least two points of intersection.

3. The silicon carbide crystal growth crucible according to claim 1, characterized in that, The cross-sectional shape of the guide hole (33) along the direction perpendicular to the first surface (31) is a parallelogram.

4. The silicon carbide crystal growth crucible according to claim 3, characterized in that, One interior angle of the parallelogram is α, and 15°≤α≤75°.

5. The silicon carbide crystal growth crucible according to claim 1, characterized in that, The receiving cavity (11) has a protrusion (111) on the inner wall surface near the cover (2), and the protrusion (111) is a continuous annular structure or an intermittent annular structure.

6. The silicon carbide crystal growth crucible according to claim 1, characterized in that, The main body (1), the cover (2) and the guide (3) are all made of graphite.

7. The silicon carbide crystal growth crucible according to claim 1, characterized in that, The cover (2) includes: The crucible lid (21) has an interior cavity (211) with an opening, the opening of which is opposite to the opening of the receiving cavity (11); A growth plate (22) is disposed inside the cavity (211) for placing seed crystals (221).

8. The silicon carbide crystal growth crucible according to claim 7, characterized in that, The crucible lid (21) has multiple through holes (212) on the end face away from the main body (1), and the multiple through holes (212) are connected to the cavity (211).

9. A silicon carbide crystal growth apparatus, characterized in that, include: The growth crucible as described in any one of claims 1 to 8; Heating device (4) is located at the bottom of the growth crucible.

10. A method for growing silicon carbide crystals, implemented based on the silicon carbide crystal growth apparatus of claim 9, characterized in that, The method includes: 4H-SiC was selected as the seed crystal (221), and the seed crystal (221) was fixed on the surface of the growth plate (22) near the body part (1); The silicon carbide raw material (112) is placed into the receiving cavity (11), and the main body (1), the cover (2) and the guide (3) are assembled. The growth apparatus for silicon carbide crystal is heated by heating device (4), and the temperature near growth plate (22) is controlled to be greater than or equal to 2130°C and less than or equal to 2200°C. The pressure between the containment cavity (11) and the cavity (211) is controlled to be greater than or equal to 500Pa and less than or equal to 1000Pa.

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