Silicon carbide crystal growing device

Abstract

The invention discloses a silicon carbide crystal growth device. The silicon carbide crystal growth device comprises a growth container; the powder container is suitable for containing silicon carbide powder, the powder container is arranged in the growth container, and a containing space is formed between the outer circumferential surface of the powder container and the inner circumferential surface of the growth container; the flow guide cylinder comprises a plurality of arc-shaped flow guide parts which can be mutually separated in the circumferential direction, the flow guide cylinder is supported on the upper end face of the powder container, and each arc-shaped flow guide part can move in the radial direction and is constructed to be suitable for sliding to the containing space from the upper end face of the powder container under the pushing of growing polycrystals. According to the silicon carbide crystal growing device, the dislocation defect density of a crystal basal plane can be reduced, an annealing process and growing temperature do not need to be sacrificed, and the silicon carbide crystal growing device has the advantages of small crystal defects, high production efficiency and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicon carbide crystal growth, in particular to a silicon carbide crystal growth device. BACKGROUND

[0002] There are three main linear dislocation defects in the dislocation defects of the silicon carbide crystal produced by the physical vapor transport (PVT) method, which are respectively a screw dislocation (TSD), a threading edge dislocation (TED) and a basal plane dislocation (BPD). The basal plane dislocation (BPD) has a great influence on the performance of a device. The BPD is mainly affected by the temperature distribution, the temperature gradient and the thermal annealing.

[0003] In the related art, the way to reduce the BPD defect density is to shorten the annealing time or reduce the annealing temperature by adjusting the temperature of the external thermal field in the high-temperature section after the growth of the silicon carbide crystal is completed, or even to use the "quenching" method. However, due to the excellent heat preservation of the thermal field of the silicon carbide crystal, there is a very large hysteresis in the external adjustment of the annealing process. Moreover, shortening the annealing time or reducing the annealing temperature may cause the generation of other serious defects, cause the crystal to have a large residual stress, even cause the crystal to crack, and affect the surface control in the subsequent processing process. Or, in the process of crystal growth, the thermal stress is slowed down by reducing the growth temperature of the crystal to induce the BPD defect, but this will reduce the growth rate of the crystal and affect the production efficiency. SUMMARY

[0004] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a silicon carbide crystal growth device which can reduce the basal plane dislocation defect density of the crystal without sacrificing the annealing process and the growth temperature, and has the advantages of small crystal defects, high production efficiency, etc.

[0005] To achieve the above-mentioned purpose, according to an embodiment of the present application, a silicon carbide crystal growth device is provided, which comprises: a growth container; a powder container adapted to contain silicon carbide powder, the powder container being arranged in the growth container and having a containing space between the outer periphery of the powder container and the inner periphery of the growth container; a flow guide cylinder comprising a plurality of arc-shaped flow guide members which can be separated from each other in the circumferential direction, the flow guide cylinder being supported on the upper end surface of the powder container, and each arc-shaped flow guide member being movable in the radial direction and being configured to be adapted to slide from the upper end surface of the powder container to the containing space under the push of the growing polycrystal.

[0006] The silicon carbide crystal growth device according to the embodiment of the present application can reduce the basal plane dislocation defect density of the crystal without sacrificing the annealing process and the growth temperature, and has the advantages of small crystal defects, high production efficiency, etc.

[0007] In addition, the silicon carbide crystal growth device according to the above-mentioned embodiment of the present application can further have the following additional technical features. According to one embodiment of the present application, the crystal growth rate of the silicon carbide crystal growth device is 10.5-12 g / h.

[0008] According to one embodiment of the present application, the silicon carbide crystal growth device further comprises a seed plate adapted to bond a seed crystal, the seed plate being located above and spaced apart from the flow guide cylinder, the flow guide cylinder being spaced apart from the seed crystal, the seed plate being provided with a plurality of exhaust holes, the exhaust holes being located radially outward of the flow guide cylinder, and the plurality of exhaust holes being spaced apart circumferentially.

[0009] According to one embodiment of the present application, the flow guide cylinder is spaced apart from the seed crystal by 1-3 mm in the radial direction, the flow guide cylinder is spaced apart from the seed crystal by 1-2 mm in the vertical direction, and the contact surface between the lower end surface of the flow guide cylinder and the upper end surface of the powder container has a width of 1-3 mm in the radial direction.

[0010] According to one embodiment of the present application, the outer edge of the lower end surface of the flow guide cylinder is provided with a limiting protrusion, and the limiting protrusion is in abutment with the outer circumferential surface of the powder container.

[0011] According to one embodiment of the present application, the inner circumferential surface of the limiting protrusion is formed with an outer guide surface inclined outward from top to bottom.

[0012] According to one embodiment of the present application, the upper end of the outer circumferential surface of the powder container is formed with an inner guide surface inclined outward from top to bottom.

[0013] According to one embodiment of the present application, the diameter of the flow guide cylinder gradually increases from top to bottom.

[0014] According to one embodiment of the present application, the arc-shaped flow guide members are four and each of the arc-shaped flow guide members is a quarter of a circular arc.

[0015] According to one embodiment of the present application, the accommodating space is provided with a buffer member.

[0016] Additional aspects and advantages of the present application will be made apparent by the following description and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0017] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood by considering the following detailed description, including the accompanying drawings, in which: Figure 1 is a sectional view of a silicon carbide crystal growth device according to some embodiments of the present application.

[0018] Figure 2 is a sectional view of a silicon carbide crystal growth apparatus according to another embodiment of the present application.

[0019] Figure 3 is a sectional view of a silicon carbide crystal growth apparatus according to another embodiment of the present application.

[0020] Figure 4 is a sectional view of a silicon carbide crystal growth apparatus according to another embodiment of the present application.

[0021] Figure 5 is a sectional view of a silicon carbide crystal growth apparatus according to another embodiment of the present application.

[0022] Figure 6 is a sectional view of a silicon carbide crystal growth apparatus according to another embodiment of the present application.

[0023] Figure 7 is a sectional view of a silicon carbide crystal growth apparatus according to another embodiment of the present application.

[0024] Figure 8 is a sectional view of a silicon carbide crystal growth apparatus according to another embodiment of the present application.

[0025] Figure 9 is a sectional view of a silicon carbide crystal growth apparatus according to another embodiment of the present application.

[0026] Figure 10 is a sectional view of a silicon carbide crystal growth apparatus according to another embodiment of the present application.

[0027] Figure 11 is a sectional view of a silicon carbide crystal growth apparatus according to another embodiment of the present application.

[0028] Figure 12 is a sectional view of a silicon carbide crystal growth apparatus according to another embodiment of the present application.

[0029] Reference signs: silicon carbide crystal growth apparatus 1, growth container 10, containing space 11, graphite cylinder 12, powder container 20, porous graphite plate 21, flow guide cylinder 30, arc-shaped flow guide 31, limiting convex edge 32, seed plate 40, exhaust hole 41, buffer 50, quartz cylinder 60, induction coil 70, heat insulation felt 80, temperature measuring hole 81, carrier disc 90, silicon carbide powder 2, seed crystal 3, single crystal 4, polycrystal 5. DETAILED DESCRIPTION

[0030] The present application is made based on the following facts and problems: In the related art, the way to reduce the BPD defect density is to shorten the annealing time or reduce the annealing temperature by adjusting the external thermal field temperature in the high-temperature section after the silicon carbide crystal growth is completed, or even to use the "quenching" method. However, due to the excellent heat preservation of the silicon carbide crystal growth thermal field, there is a very large hysteresis in the external adjustment of the annealing process. Moreover, shortening the annealing time or reducing the annealing temperature may cause the generation of other serious defects, cause the crystal to have a large residual stress, and even cause the crystal to crack, thereby affecting the surface control in the subsequent processing process. Or, in the crystal growth process, the BPD defects are reduced by reducing the growth temperature of the crystal to slow down the thermal stress, but this will reduce the crystal growth rate and affect the production efficiency.

[0031] Specifically, in the related art, a flow guide cylinder needs to be arranged to guide and limit the flow of the gas phase components during the crystal growth process. After the crystal growth, the flow guide cylinder is located radially outside the crystal. During the annealing process, since the flow guide cylinder is a graphite material, the flow guide cylinder will affect the crystal through heat conduction and heat radiation, causing the crystal to be subjected to a large thermal stress, thereby increasing the BPD defect density of the crystal.

[0032] Embodiments of the present application will be described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0033] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application. In addition, the features defined as "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise stated, the meaning of "a plurality of" is two or more. In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "linking" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal connection of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0034] A silicon carbide crystal growth device 1 according to an embodiment of the present application will be described below with reference to the accompanying drawings.

[0035] As shown in the drawings, the silicon carbide crystal growth device 1 according to an embodiment of the present application includes a growth container 10, a powder container 20 and a draft tube 30. Figures 1-12 The powder container 20 is adapted to contain silicon carbide powder 2, and the powder container 20 is arranged in the growth container 10, and a containing space 11 is provided between the outer peripheral surface of the powder container 20 and the inner peripheral surface of the growth container 10. The draft tube 30 includes a plurality of arc-shaped draft members 31 which are separable from each other in the circumferential direction, and the draft tube 30 is supported on the upper end surface of the powder container 20 (the up-down direction is shown by the arrow in the drawing), and each arc-shaped draft member 31 is movable in the radial direction and is configured to be adapted to slide from the upper end surface of the powder container 20 to the containing space 11 under the pushing of the growing crystal.

[0036] Specifically, the growth container 10 can include a container body and a container cover, and the growth container 10 can be a crucible.

[0037] During the crystal growth process, the volume of the crystal gradually increases as the crystal grows, and the volume of the crystal continues to increase after the crystal contacts the draft tube 30, pushing the draft tube 30 to move, pushing the draft tube 30 to the radial outside of the powder container 20, and the draft tube 30 falls into the containing space 11 under the action of gravity.

[0038] After that, the annealing stage is entered, and since the draft tube 30 has fallen into the containing space 11, the crystal is no longer affected by the draft tube 30 around the crystal, reducing the heat conduction and heat radiation received by the crystal, effectively reducing the thermal stress of the crystal edge, and greatly reducing the thermal induced BPD defect density of the crystal edge.

[0039]

[0040] ​According to the silicon carbide crystal growth device 1 of the embodiment of the present application, by arranging the accommodating space 11 and arranging the flow guide cylinder 30 to include a plurality of arc-shaped flow guide members 31 which are separable from each other in the circumferential direction, the flow guide cylinder 30 is supported on the upper end surface of the powder container 20, and each arc-shaped flow guide member 31 is movable in the radial direction, so that the arc-shaped flow guide member 31 can slide from the upper end surface of the powder container 20 to the accommodating space 11 under the pushing of the growing crystal. Compared with the silicon carbide crystal growth device in the related art, the arc-shaped flow guide member 31 can be moved by the pushing of the crystal growth before the annealing process in the crystal growth process, so that the arc-shaped flow guide member 31 slides to the accommodating space 11, and thus the flow guide cylinder 30 does not affect the annealing process of the crystal by heat conduction and heat radiation in the annealing stage, the thermal stress of the crystal edge is effectively reduced, the basal plane dislocation defect density of the crystal edge caused by thermal induction is greatly reduced, the flow guide cylinder 30 is driven by the crystal growth, and other structures for driving the flow guide cylinder 30 in the growth container 10 are not needed, so that the structure of the silicon carbide crystal growth device 1 can be simplified, and the design and manufacturing difficulty of the silicon carbide crystal growth device 1 is reduced.

[0041] In addition, by making the flow guide cylinder 30 slide to the accommodating space 11 before the annealing process to avoid affecting the annealing process of the crystal and reduce the basal plane dislocation defect density of the crystal, compared with the way of reducing the annealing temperature and shortening the annealing time in the related art, the annealing temperature and time of the crystal do not need to be sacrificed, the crystal can be effectively annealed, the internal stress of the silicon carbide crystal is released in the annealing process, the defects such as cracking and large stress of the crystal are avoided, and the surface control in the subsequent processing process is not affected.

[0042] In addition, by making the flow guide cylinder 30 slide to the accommodating space 11 before the annealing process to avoid affecting the annealing process of the crystal and reduce the basal plane dislocation defect density of the crystal, compared with the way of reducing the growth temperature to reduce the basal plane dislocation defect density in the related art, the silicon carbide crystal growth device 1 can still maintain a high growth rate, the crystal growth period is shortened, the crystal production efficiency is improved, and the time and energy cost are saved.

[0043] Therefore, the silicon carbide crystal growth device 1 according to the embodiment of the present application can reduce the basal plane dislocation defect density of the crystal without sacrificing the annealing process and the growth temperature, has the advantages of small crystal defect and high production efficiency.

[0044] Hereinafter, the silicon carbide crystal growth device 1 according to the embodiment of the present application will be described with reference to the accompanying drawings.

[0045] In some embodiments of the present application, as shown in Figures 1-12 The silicon carbide crystal growth device 1 according to the embodiment of the present application includes a growth container 10, a powder container 20 and a flow guide cylinder 30.

[0046] Specifically, as shown in Figures 1-10 andFigure 12 As shown, the silicon carbide crystal growth device 1 further comprises a seed plate 40, on which the seed crystal 3 is adapted to be bonded, and the seed plate 40 is arranged above and spaced from the draft tube 30, and the draft tube 30 is spaced from the seed crystal 3. In this way, not only can the seed crystal 3 be bonded conveniently, but also the seed plate 40 and the seed crystal 3 can be prevented from directly contacting the draft tube 30 to affect the movement of the draft tube 30.

[0047] In some embodiments, as Figures 1-5 As shown, the diameter of the draft tube 30 is uniform. In other words, the diameter of the draft tube 30 does not change in the up-down direction, and the crystal grows at a constant diameter under the guiding effect of the draft tube 30.

[0048] Specifically, as Figure 5 As shown, due to the gap between the draft tube 30 and the seed crystal 3, part of the sublimated gas phase components will flow out between the draft tube 30 and the seed crystal 3, and start to deposit polycrystal 5 relying on the seed plate 40. As the crystal growth proceeds, the polycrystal 5 at the edge of the single crystal 4 also grows continuously. Since the growth rate of the polycrystal 5 is higher than that of the single crystal 4, when the thickness of the polycrystal 5 grown laterally exceeds the radial width of the contact surface between the draft tube 30 and the powder container 20, the draft tube 30 is repelled and slides down to the accommodation space 11. In addition, due to the large axial temperature gradient and the generally small radial temperature gradient in the physical vapor transport method of silicon carbide crystal growth, the axial and radial growth rates of the polycrystal 5 are different, which enables the polycrystal 5 to gradually extend into the draft tube 30 while increasing the thickness radially outward during the growth process, thereby pushing the draft tube 30 to move and slide down.

[0049] The seed plate 40 is provided with a plurality of exhaust holes 41, which are located radially outward of the draft tube 30 and are circumferentially spaced. Specifically, the seed plate 40 is spaced from the inner top surface of the container cover of the growth container 10 to form an exhaust space, and the exhaust holes 41 communicate with the exhaust space. The exhaust holes 41 are 10 mm away from the outer edge of the seed crystal 3, the diameter of the exhaust holes 41 is 2.5 mm, and there are 16 exhaust holes 41, so as to ensure smooth exhaust. In this way, the excess gas phase components flowing out of the draft tube 30 through the exhaust holes 41 can be removed, preventing the polycrystal from being generated on the outside of the draft tube 30 to hinder the movement of the draft tube 30.

[0050] Advantageously, the crystal growth rate of the silicon carbide crystal growth device 1 is 10.5-12 g / h. Specifically, when the growth rate is too low, it can result in insufficient radial thickness growth of the polycrystal 5, causing the draft tube 30 to fail to slide off. When the growth rate is too high, due to the too fast radial thickness growth of the polycrystal 5, the draft tube 30 slides off too early, causing the edge polycrystal 5 to no longer be limited during the remaining growth process, resulting in too fast growth rate of the polycrystal 5, thus causing a series of crystal growth defects caused by the polycrystal 5, such as polycrystal embedding in the single crystal 4 region, polycrystal-induced cracks and phase changes, etc. Thus, when the crystal growth rate is 10.5-12 g / h, the crystal growth can be ended, the draft tube can be effectively repelled, and at the same time, a high vapor component sublimation rate can be ensured, the inner edge of the draft tube 30 and the outer edge of the polycrystal 5 are washed by the vapor component, and the separation can be better.

[0051] Further, the draft tube 30 is spaced apart from the seed crystal 3 by 1-3 mm in the radial direction, and the draft tube 30 is spaced apart from the seed crystal 3 by 1-2 mm in the up-down direction. Here, the draft tube 30 is preferably spaced apart from the seed crystal 3 by 2 mm in the radial direction, and the draft tube 30 is preferably spaced apart from the seed crystal 3 by 1.5 mm in the up-down direction. In this way, it can be facilitated to ensure that there is sufficient gap between the draft tube 30 and the seed crystal 3, not only can the movement of the draft tube 30 be avoided, but also the outflow of the vapor component can be facilitated.

[0052] The width of the contact surface between the draft tube 30 and the upper end surface of the powder container 20 in the radial direction is 1-3 mm. Here, the width of the contact surface between the draft tube 30 and the upper end surface of the powder container 20 in the radial direction is preferably 2 mm. In this way, it can be facilitated to control the contact area between the draft tube 30 and the powder container 20, and the draft tube 30 can be prevented from sliding off too early or being difficult to slide off.

[0053] Specifically, the axial temperature gradient during the physical vapor transport method silicon carbide crystal growth process is large, which can be controlled at 30-60 ℃ / cm, and the radial temperature gradient is usually small, which does not exceed 10 ℃ / cm. Therefore, by utilizing the difference between the axial and radial growth rates, when the crystal growth rate of the silicon carbide crystal growth device 1 is 10.5-12 g / h, the axial thickness of the polycrystal grows to 24-26 mm, and the radial thickness grows more than 2 mm, so that the draft tube can be repelled after the crystal growth is ended.

[0054] More advantageously, as Figures 2-6As shown, the outer edge of the lower end surface of the draft tube 30 is provided with a limiting protrusion 32, which abuts against the outer circumferential surface of the powder container 20. In this way, the limiting protrusion 32 can be used to limit the moving direction of the draft tube 30, so as to avoid asymmetric displacement of the plurality of arc-shaped draft members 31 of the draft tube 30, avoid the situation that one side of the arc-shaped draft members 31 moves while the other side does not move, or even the situation that one side of the arc-shaped draft members 31 presses the other side of the arc-shaped draft members 31 to move in the opposite direction, so as to ensure that the arc-shaped draft members 31 can move and slide down as expected.

[0055] Further, as shown, Figures 3-6 the inner circumferential surface of the limiting protrusion 32 is formed with an outer guide surface that is inclined outward from top to bottom. In this way, the draft tube 30 can be further facilitated to slide down under the guidance of the outer guide surface.

[0056] Still further, as shown, Figures 3-10 the upper end of the outer circumferential surface of the powder container 20 is formed with an inner guide surface that is inclined outward from top to bottom. In this way, the draft tube 30 can be further facilitated to slide down under the guidance of the inner guide surface.

[0057] In the embodiment shown, Figure 1 the controlled crystal growth rate is 11.85g / h. The specific crystal growth process is as follows: vacuum acquisition for 2h30min; vacuum leak detection for 30min; high flow rate pressure control, within 30min, argon (Ar) flow rate 800sccm, nitrogen (N2) flow rate 0sccm, pressure control 500mbar, power 0kw; low flow rate pressure control, within 30min, argon (Ar) flow rate 100sccm, nitrogen (N2) flow rate 20sccm, pressure control 500mbar, power 0kw; power increase control, within 1h, argon (Ar) flow rate 100sccm, nitrogen (N2) flow rate 5sccm, pressure control 300mbar, power 5.5kw; power increase control, within 1h, argon (Ar) flow rate 100sccm, nitrogen (N2) flow rate 8sccm, pressure control 100mbar, power 12.5kw; power increase control, within 1h, argon (Ar) flow rate 100sccm, nitrogen (N2) flow rate 8sccm, pressure control 50mbar, power 14.5kw; power increase control, within 1h, argon (Ar) flow rate 100sccm, nitrogen (N2) flow rate 8sccm, pressure control 5mbar, power 16.5kw; Power control: within 1 hour, argon (Ar) flow rate 100 sccm, nitrogen (N2) flow rate 8 sccm, pressure control 1.5 mbar, power 18.5 kW; Crystal growth, within 5 hours, argon (Ar) flow rate 100 sccm, nitrogen (N2) flow rate 20 sccm, pressure controlled at 1.5 mbar, power 18.5 kW; Crystal growth, within 90 hours, argon (Ar) flow rate 100 sccm, nitrogen (N2) flow rate 25 sccm, pressure controlled at 1.5 mbar, power 20.5 kW; In-situ annealing, within 12 hours, argon (Ar) flow rate 100 sccm, nitrogen (N2) flow rate 0 sccm, pressure control 800 mbar, power 18.5 kW; Cooling, within 50 minutes, argon (Ar) flow rate 100 sccm, nitrogen (N2) flow rate 0 sccm, pressure control 800 mbar, power 0 kW; Cooling, within 24 hours, argon (Ar) flow rate 100 sccm, nitrogen (N2) flow rate 0 sccm, pressure control 800 mbar, power 0 kW; Start the furnace.

[0058] In other embodiments, such as Figures 6-10 As shown, the diameter of the flow guide tube 30 gradually increases from top to bottom. This allows the single crystal 4 to expand in diameter under the guidance of the flow guide tube 30. The gradual increase in diameter of the single crystal 4 from top to bottom effectively pushes the flow guide tube 30 down during the growth process, eliminating the need for polycrystalline growth. This also eliminates the need to adjust the polycrystalline growth rate by adjusting the crystal growth rate of the silicon carbide crystal growth device 1. Furthermore, the flow guide tube 30 can limit polycrystalline growth, avoiding a series of crystal growth defects caused by polycrystalline growth, which is beneficial for improving crystal quality and yield.

[0059] Specifically, such as Figure 10 As shown, the radial straight-line distance between the inner edge of the top diameter of the guide tube 30 and the outer edge of the bottom diameter of the guide tube 30 is d, the axial height of the guide tube 30 (crystal growth thickness) is h, and the diameter expansion angle between the vertical projection lines along the height direction of the guide tube 30 is θ. These three satisfy tanθ = d / h. During the silicon carbide crystal diameter expansion growth process, the straight-line distance d and the crystal thickness h can be flexibly controlled. For example, if the diameter expansion angle is set to 15° and the lateral straight-line distance d remains 5mm, then the crystal thickness can exceed 18.66mm. As another example, if the diameter expansion angle is set to 5°, the lateral straight-line distance d can be significantly reduced; for example, if the crystal thickness is controlled to 17.15mm, then d only needs to be 1.5mm. The range of selectable diameter expansion angles is relatively large, generally not exceeding 30°.

[0060] Optionally, such as Figure 11As shown, the plurality of arc-shaped flow guides 31 can be equal-division arcs of the flow guide cylinder 30, for example, bisecting arcs, trisecting arcs, etc. Here, it is preferred that the arc-shaped flow guides 31 are four and each arc-shaped flow guide 31 is a quarter arc. Since the fewer the number of arc-shaped flow guides 31, the greater the concentric arc cut angle, the greater the radial width of the accommodating space 11 required, by providing four arc-shaped flow guides 31, each arc-shaped flow guide 31 can have a greater concentric arc cut angle, facilitating control of the radial width of the accommodating space 11. Specifically, as shown in Figures 1-10 As shown, the accommodating space 11 is provided with a buffer 50. Specifically, the buffer 50 can be graphite soft felt and the thickness is 10 mm. The buffer 50 is provided above the graphite cylinder 12. In this way, it is convenient to buffer the dropped flow guide cylinder 30.

[0061] Specifically, as shown in Figures 1-10 As shown, the accommodating space 11 is also provided with a graphite cylinder 12, which abuts the inner circumferential surface of the growth container 10 and the outer circumferential surface of the powder container 20, so as to facilitate the heating effect of the powder container 20.

[0062] As shown in Figure 12 The silicon carbide crystal growth device 1 further comprises a quartz cylinder 60, an induction coil 70, a heat preservation felt 80 and a carrier plate 90. The induction coil 70 provides a heat source by induction heating. The heat preservation felt 80 is graphite hard felt with a purity of 30-50 ppm, and the heat preservation felt 80 is provided with a temperature measuring hole 81.

[0063] Figure 1 The embodiment shown is embodiment 1, Figure 2 The embodiment shown is embodiment 2, Figures 3-5 The embodiment shown is embodiment 3, Figure 6 The embodiment shown is embodiment 4, Figures 7-10 The embodiment shown is embodiment 5, and the experimental verification shows that the crystal defects of the equal-diameter flow guide cylinder and the expanded-diameter flow guide cylinder in embodiments 1-5 and the related art are as shown in the following table:

[0064] It can be seen that the crystal grown by the silicon carbide crystal growth device 1 according to the embodiment of the present application has a significant improvement in basal plane dislocation defects.

[0065] Other configurations and operations of the silicon carbide crystal growth device 1 according to the embodiment of the present application are known to those skilled in the art, and will not be described in detail here.

[0066] In the description of the specification, reference to "one embodiment", "some embodiments", "an exemplary embodiment", "an example", "a specific example", or "some examples" means that a particular feature, structure, material, or characteristic being described is included in at least one embodiment or example of the application. The appearances of the phrases "in one embodiment", "in some embodiments", "in an exemplary embodiment", "an example", "a specific example", or "some examples" in various places in the specification are not necessarily referring to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0067] Although embodiments of the application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and alterations can be made hereto without departing from the principles and the scope of the application, which is defined by the claims and their equivalents.

Claims

1. A silicon carbide crystal growth apparatus, characterized in that, The application relates to a silicon carbide crystal growth device, which comprises: a growth container; a powder container, which is adapted to contain silicon carbide powder, is arranged in the growth container, and has a containing space between the outer periphery of the powder container and the inner periphery of the growth container; a draft tube, which comprises a plurality of arc-shaped draft members that can be separated from each other in the circumferential direction, is supported on the upper end surface of the powder container, and each arc-shaped draft member can move in the radial direction and is configured to slide from the upper end surface of the powder container to the containing space under the push of a growing crystal.

2. The silicon carbide crystal growth apparatus of claim 1, wherein, The crystal growth rate of the silicon carbide crystal growth device is 10.5-12 g / h.

3. The silicon carbide crystal growth apparatus of claim 1, wherein, The device further comprises a seed plate, which is adapted to bond a seed crystal, is arranged above the draft tube and is spaced apart from the draft tube, the draft tube is spaced apart from the seed crystal, and the seed plate is provided with a plurality of exhaust holes, the exhaust holes are located radially outside the draft tube, and the plurality of exhaust holes are arranged in the circumferential direction.

4. The silicon carbide crystal growth apparatus of claim 3, wherein The draft tube is spaced apart from the seed crystal by 1-3 mm in the radial direction, the draft tube is spaced apart from the seed crystal by 1-2 mm in the vertical direction, and the contact surface between the draft tube and the upper end surface of the powder container has a width of 1-3 mm in the radial direction.

5. The silicon carbide crystal growth apparatus of claim 1, wherein, The outer edge of the lower end surface of the draft tube is provided with a limiting convex edge, and the limiting convex edge abuts against the outer periphery of the powder container.

6. The silicon carbide crystal growth apparatus of claim 5, wherein, The inner periphery of the limiting convex edge is formed with an outer guide surface that is inclined outward from top to bottom.

7. The silicon carbide crystal growth apparatus of claim 1, wherein The upper end of the outer periphery of the powder container is formed with an inner guide surface that is inclined outward from top to bottom.

8. The silicon carbide crystal growth apparatus of claim 1, wherein, The diameter of the draft tube gradually increases from top to bottom.

9. The silicon carbide crystal growth apparatus of claim 1 wherein, The arc-shaped draft members are four, and each arc-shaped draft member is a quarter of a circular arc.

10. The silicon carbide crystal growth apparatus of claim 1, wherein, The containing space is provided with a buffer member.

Images