Device and method for growing high-quality silicon carbide crystal and silicon carbide crystal

Abstract

The present invention relates to the field of silicon carbide crystal growth, and provides a device and method for growing a high-quality silicon carbide crystal and a silicon carbide crystal. An annular flow guide plate used for guiding a gas-phase crystal growth component to flow to a seed crystal is arranged in the device, and a pressure equalizing structure is arranged on the annular flow guide plate; by arranging the pressure equalizing structure on the annular flow guide plate, the pressure difference between a second chamber above the annular flow guide plate and a first chamber below the annular flow guide plate can be effectively reduced, so that the pressures of the two chambers are close to each other as much as possible, the flow velocity of a gas-phase crystal growth component in a gap between the top end of the annular flow guide plate and the edge of a seed crystal can be effectively reduced, and thus the growth speed of a silicon carbide crystal at the edge of the seed crystal is as same as possible as that of a silicon carbide crystal at the center of the seed crystal, thereby avoiding the defects of a concave interface and the like of a silicon carbide crystal growing on the seed crystal and improving the growth quality of a silicon carbide crystal. The silicon carbide crystal prepared by the method has the characteristics of few defects and high quality.

Description

Device and method for growing high-quality silicon carbide crystals, and silicon carbide crystals Technical Field

[0001] The present invention relates to the field of silicon carbide crystal growth, and in particular to a device and method for growing high-quality silicon carbide crystals and the silicon carbide crystals. Background Art

[0002] As a representative of the third-generation semiconductor materials, silicon carbide is widely used in power electronics, radio frequency devices, optoelectronic devices and other fields due to its excellent properties such as large bandgap, high saturated electron mobility, strong breakdown field and high thermal conductivity.

[0003] In order to increase the growth rate of silicon carbide crystals on seed crystals and limit the size and shape of silicon carbide crystals, a guide plate is generally provided in the upper middle part of the crucible to guide the gas phase growth component (mainly Si m C n , that is, the carbon-silicon component) flows as much as possible toward the seed crystal. However, to prevent interference between the guide plate and the seed crystal, a gap is usually reserved between the top of the guide plate and the edge of the seed crystal. This gap causes a certain pressure difference between the chamber above the guide plate and the chamber below it in the early stages of SiC crystal growth. This causes the gas-phase growth component to flow faster and more rapidly in this gap, resulting in excessive growth at the edge of the seed crystal and the formation of a "concave interface", which affects the growth quality of the SiC crystal. Summary of the Invention

[0004] The objects of the present invention include, for example, providing an apparatus, method and silicon carbide crystal for growing high-quality silicon carbide crystals, which can effectively reduce the flow rate of the gas phase crystal growth component in the gap between the top of the guide plate and the edge of the seed crystal, so that the silicon carbide crystal can grow uniformly in all parts of the seed crystal, thereby improving the growth quality of the silicon carbide crystal.

[0005] The embodiments of the present invention can be implemented as follows:

[0006] In a first aspect, the present invention provides an apparatus for growing high-quality silicon carbide crystals, comprising:

[0007] a crucible, wherein a top wall of the crucible is provided with a seed crystal for growing silicon carbide crystals;

[0008] An annular guide plate is arranged in the crucible, the bottom end of the annular guide plate is connected to the side wall of the crucible, the top end extends toward the seed crystal and has a gap with the edge of the seed crystal, the annular guide plate, the seed crystal, the side wall of the crucible, and the bottom wall of the crucible together form a first chamber, the annular guide plate, the seed crystal, the side wall of the crucible and the top wall of the crucible together form a second chamber, the first chamber and the second chamber are connected through the gap, and a pressure equalizing structure for balancing the pressure of the first chamber and the second chamber is provided on the annular guide plate.

[0009] In an optional embodiment, the pressure equalizing structure includes an air hole opened on the annular guide plate, and the air hole connects the first chamber and the second chamber.

[0010] In an optional embodiment, there are a plurality of air holes, and the plurality of air holes are arranged in one or more circles around the axis of the crucible.

[0011] In an optional embodiment, the plurality of air holes are arranged in multiple circles around the axis of the crucible, the multiple circles of air holes are spaced apart in the radial direction of the crucible, and any two adjacent circles of air holes are staggered in the radial direction of the crucible.

[0012] In an optional embodiment, the annular guide plate includes a first annular portion and a second annular portion connected at an angle, the end of the first annular portion away from the second annular portion is connected to the inner wall of the crucible, the end of the second annular portion away from the first annular portion extends toward the seed crystal, and the air hole is opened in the first annular portion.

[0013] In an optional embodiment, the first annular portion is flat and perpendicular to the axis of the crucible, the outer circumferential wall of the first annular portion is connected to the side wall of the crucible, the second annular portion is hollow cylindrical or hollow conical, the bottom end of the second annular portion is connected to the inner circumferential wall of the first annular portion, and the top end extends toward the seed crystal.

[0014] In an optional embodiment, the pores are arranged to be inclined toward the seed crystal.

[0015] In an optional embodiment, the pore diameter gradually decreases in a direction approaching the seed crystal.

[0016] In an optional embodiment, the pressure equalizing structure includes silicon carbide powder placed in the second chamber.

[0017] In an optional embodiment, at least one concentration adjustment through hole is provided on the crucible at the periphery of the second chamber.

[0018] In an optional embodiment, the first annular portion includes a plurality of sub-annular portions distributed vertically, and the air holes are distributed on each sub-annular portion.

[0019] In an optional embodiment, along the transport direction of the crystal growth component, several layers of the sub-annular portions have pores with gradually smaller diameters.

[0020] In a second aspect, an embodiment of the present invention further provides a method for growing high-quality silicon carbide crystals, which is based on the apparatus for growing high-quality silicon carbide crystals described in any of the above embodiments, comprising:

[0021] placing silicon carbide powder in the crucible;

[0022] The crucible is evacuated and then filled with an inert gas;

[0023] Heating the crucible to raise the temperature inside the crucible to 2000-2600° C.;

[0024] The crucible is evacuated again to reduce the pressure inside the crucible to 0.01-4E3Pa;

[0025] The silicon carbide powder sublimates and begins to grow silicon carbide crystals on the seed crystals;

[0026] After the silicon carbide crystals have grown for 10-300 hours, the crucible is refilled with inert gas to increase the pressure inside the crucible to 5E3-1E5 Pa;

[0027] After the growth of the silicon carbide crystal is completed, the crucible is stopped from being heated. After the temperature inside the crucible drops to room temperature, the silicon carbide crystal is taken out of the crucible.

[0028] In a third aspect, the present invention further provides a silicon carbide crystal, which is prepared using the method for growing high-quality silicon carbide crystals described in the above embodiment.

[0029] The beneficial effects of the embodiments of the present invention include, for example:

[0030] The device for growing high-quality silicon carbide crystals provided by the present invention includes a crucible and an annular guide plate, wherein the top wall of the crucible is provided with a seed crystal for growing silicon carbide crystals. The annular guide plate is disposed in the crucible, the bottom end of the annular guide plate being connected to the side wall of the crucible, the top end extending toward the seed crystal and having a gap between it and the edge of the seed crystal. The annular guide plate, the seed crystal, the side wall of the crucible, and the bottom wall of the crucible together form a first chamber, and the annular guide plate, the seed crystal, the side wall of the crucible, and the top wall of the crucible together form a second chamber, and the first chamber and the second chamber are connected by the gap. A pressure equalizing structure for balancing the pressure in the first chamber and the second chamber is provided on the annular guide plate. By setting up the pressure equalizing structure on the annular guide plate, the pressure difference between the first chamber and the second chamber can be effectively reduced, so that the pressures of the two chambers are as close as possible. This can effectively reduce the flow rate of the gas phase crystal growth component in the gap between the top of the annular guide plate and the edge of the seed crystal, so that the growth rate of the silicon carbide crystal at the edge of the seed crystal is as similar as possible to the growth rate of the silicon carbide crystal in the center of the seed crystal, thereby avoiding defects such as "concave interface" in the silicon carbide crystal on the seed crystal and improving the growth quality of the silicon carbide crystal.

[0031] From another perspective, the present invention avoids excessive concentration of crystal growth gas phase components at the edge of the crystal, excessive growth rate leading to defects such as edge polycrystalline and phase change, or formation of concave crystal interface affecting crystal growth quality by controlling the radial concentration distribution of crystal growth gas phase components.

[0032] Accordingly, the method for growing high-quality silicon carbide crystals adopts the above-mentioned device, and the silicon carbide crystals prepared therefrom have the characteristics of few defects and high quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0034] FIG1 is a schematic structural diagram of an apparatus for growing high-quality silicon carbide crystals provided by a first embodiment of the present invention;

[0035] FIG2 is a schematic structural diagram of an annular guide plate provided in a first embodiment of the present invention;

[0036] FIG3 is a schematic structural diagram of an apparatus for growing high-quality silicon carbide crystals provided by a second embodiment of the present invention;

[0037] FIG4 is a schematic structural diagram of an apparatus for growing high-quality silicon carbide crystals provided by a fifth embodiment of the present invention;

[0038] FIG5 is a schematic structural diagram of an apparatus for growing high-quality silicon carbide crystals according to a sixth embodiment of the present invention;

[0039] Icons: 100-crucible; 102-first chamber; 104-second chamber; 106-gap; 108-concentration adjustment hole; 110-seed crystal; 200-annular guide plate; 210-first annular portion; 212-air hole; 214-sub-annular portion; 220-second annular portion; 222-rounded corner; 300-silicon carbide powder; 400-silicon carbide crystal. DETAILED DESCRIPTION

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0042] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0043] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the invention is usually placed when in use. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as a limitation on the present invention.

[0044] In addition, the terms "first", "second", etc., if used, are merely used to distinguish and describe, and should not be understood as indicating or implying relative importance.

[0045] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0046] In order to increase the growth rate of silicon carbide crystals on the seed crystals, existing crucibles used for silicon carbide crystal growth generally have guide plates on the side walls of the crucible to guide the gas-phase growth components to flow directly to the seed crystals on the top wall of the crucible. However, in order to avoid interference between the guide plate and the seed crystals, the position of the top of the guide plate is restricted, so that there is a certain gap between it and the edge of the seed crystal. This gap will cause a certain pressure difference between the chamber above the guide plate and the chamber below it in the early stage of silicon carbide crystal growth. This pressure difference will cause the flow rate of the gas-phase growth components in this gap to be very high, that is, the flow rate of the gas-phase growth components at the edge of the seed crystal is much higher than the flow rate at the center of the seed crystal. This will inevitably lead to the growth rate of the silicon carbide crystals at the edge of the seed crystal being much higher than the growth rate at the center of the seed crystal, making the silicon carbide crystals prone to defects such as "concave interfaces", seriously affecting the growth quality of the silicon carbide crystals.

[0047] In response to the above situation, the present invention provides a device and method for growing high-quality silicon carbide crystals. By arranging a pressure-equalizing structure on the guide plate in the crucible, the device can effectively balance the pressure in the upper and lower chambers of the guide plate in the crucible, effectively reduce the pressure difference between the two chambers, and thereby effectively reduce the flow rate of the gas-phase crystal growth component in the gap between the top of the guide plate and the edge of the seed crystal, so that the growth rate of the silicon carbide crystal at the edge of the seed crystal is as close as possible to the growth rate at the center of the seed crystal, thereby making the silicon carbide crystals in different parts of the seed crystal grow uniformly, avoiding defects such as "concave interface" in the silicon carbide crystal, and improving the growth quality of the silicon carbide crystal.

[0048] The overall structure, working principle, technical effects achieved, and detailed steps of the supporting method of the device for growing high-quality silicon carbide crystals provided by the present invention are described in detail below through examples and in conjunction with the accompanying drawings. First embodiment

[0049] Referring to Figures 1 and 2, the apparatus for growing high-quality silicon carbide crystals provided by the present invention includes a crucible 100, an annular guide plate 200, a heat-insulating structure (not shown), and a heating structure (not shown). The heating structure and the heat-insulating structure are both disposed on the outside of the crucible 100. The heating structure is used to generate heat in the crucible 100, thereby sublimating the silicon carbide powder 300 at the bottom of the crucible to form a vapor-phase crystal growth component. Specifically, the heating structure can be induction heating or resistance heating. The heat-insulating structure is used to slow down heat loss from the crucible 100 and can be graphite felt, graphite paper, etc.

[0050] A seed crystal 110 for growing silicon carbide crystals 400 is provided on the top wall of crucible 100 (crucible 100 generally comprises a detachably connected crucible body and a crucible lid, with the lid forming the top wall and the body forming the bottom and side walls). Seed crystals 110 may be secured by methods including, but not limited to, bonding and clamping. The bottom and side walls of crucible 100 are used to hold silicon carbide powder 300.

[0051] The annular guide plate 200 is disposed in the crucible 100 and is used to guide the vapor phase crystal growth components formed after the silicon carbide powder 300 sublimates to flow toward the seed crystal 110 , thereby achieving the growth of the silicon carbide crystal 400 .

[0052] Specifically, the bottom of the annular guide plate 200 is connected to the sidewall of the crucible 100, generally connected to the upper middle portion of the sidewall of the crucible 100. The top of the annular guide plate 200 extends toward the seed crystal 110 with a gap 106 between it and the edge of the seed crystal 110.

[0053] The annular guide plate 200 and the seed crystal 110 divide the interior space of the crucible 100 into two chambers. The annular guide plate 200, the seed crystal 110, a portion of the sidewall of the crucible 100 (the portion below the annular guide plate 200), and the bottom wall of the crucible 100 collectively form a first chamber 102. The annular guide plate 200, the seed crystal 110, a portion of the sidewall of the crucible 100 (the portion above the annular guide plate 200), and the top wall of the crucible 100 collectively form a second chamber 104. The first chamber 102 includes a large chamber and a small chamber that are interconnected. The large chamber is generally cylindrical, and the small chamber is generally truncated cone-shaped and located above the large chamber. The second chamber 104 is generally annular and disposed around the small chamber. The first chamber 102 and the second chamber 104 are connected by a gap 106 . The vapor phase growth component formed by the silicon carbide powder 300 in the crucible 100 after heating and sublimation flows upward in the first chamber 102 to the seed crystal 110 and can flow into the second chamber 104 from the annular gap 106 .

[0054] The annular guide plate 200 can adopt different structures as needed. Please refer to Figure 1 again. In this embodiment, the annular guide plate 200 includes a first annular portion 210 and a second annular portion 220 connected at an angle. The axes of the first annular portion 210 and the second annular portion 220 coincide with the axis of the crucible 100. The end of the first annular portion 210 away from the second annular portion 220 is connected to the inner wall of the crucible 100, and the end of the second annular portion 220 away from the first annular portion 210 extends toward the seed crystal 110.

[0055] In this embodiment, the first annular portion 210 is flat and perpendicular to the axis of the crucible 100. The outer circumferential wall of the first annular portion 210 is connected to the side wall of the crucible 100. The second annular portion 220 is hollow and conical. The bottom end of the second annular portion 220 is connected to the inner circumferential wall of the first annular portion 210, and the top end extends toward the seed crystal 110. The hollow conical shape can reduce resistance to the vapor-phase growth components and more effectively guide the vapor-phase growth components toward the seed crystal 110.

[0056] It should be noted that, in other embodiments, the first annular portion 210 may also be a hollow cone; the second annular portion 220 may also be a hollow cylinder; the annular guide plate 200 may also include at least three annular portions, and the at least three annular portions are connected in sequence at an angle, the lowest annular portion is connected to the side wall of the crucible 100, and the highest annular portion extends to a position close to the edge of the seed crystal 110.

[0057] Furthermore, the annular guide plate 200 is provided with a pressure equalizing structure for balancing the pressures of the first chamber 102 and the second chamber 104. The pressure equalizing structure can adopt different structures as needed. Referring to FIG. 1 again, in this embodiment, the pressure equalizing structure includes an air hole 212 provided on the annular guide plate 200. The air hole 212 connects the first chamber 102 and the second chamber 104. In other words, the first chamber 102 and the second chamber 104 are connected not only through the gap 106, but also through the air hole 212.

[0058] In this way, in addition to flowing toward the seed crystal 110 under the guidance of the annular guide plate 200, the vapor-phase growth component in the first chamber 102 can also flow into the second chamber 104 through the air hole 212 (see Figure 1 for details, the dotted line with an arrow in the figure represents the flow path of the vapor-phase growth component), so that the pressure of the second chamber 104 increases simultaneously with the pressure of the first chamber 102, thereby balancing the pressure of the first chamber 102 and the second chamber 104, reducing the pressure difference between the two, and thereby reducing the flow rate of the vapor-phase growth component at the gap 106, thereby making the growth rate of the silicon carbide crystal 400 at the edge and center of the seed crystal 110 as similar as possible, thereby avoiding the defect of "concave interface" during the growth of the silicon carbide crystal 400 and ensuring the growth quality of the silicon carbide crystal 400.

[0059] The specific position of the air hole 212 on the annular guide plate 200 can be set as needed. In this embodiment, in detail, the air hole 212 is opened in the first annular portion 210. In other embodiments, the air hole 212 can also be opened in the second annular portion 220 or opened in the first annular portion 210 and the second annular portion 220.

[0060] There are multiple air holes 212, and the multiple air holes 212 are arranged in one or more circles around the axis of the crucible 100. In this embodiment, the multiple air holes 212 are arranged in multiple circles around the axis of the crucible 100. The multiple circles of air holes 212 are spaced apart along the radial direction of the crucible 100, and any two adjacent circles of air holes 212 are staggered in the radial direction of the crucible 100. Providing multiple circles of air holes 212 around the axis of the crucible 100 effectively increases the connecting area between the first chamber 102 and the second chamber 104, thereby more effectively reducing the pressure difference between the first chamber 102 and the second chamber 104. The staggered arrangement of the air holes 212 in two adjacent circles can improve the uniformity of the multiple connecting locations between the first chamber 102 and the second chamber 104, thereby ensuring that the pressure at different locations within the second chamber 104 is as uniform as possible, facilitating a rapid increase in the pressure within the second chamber 104 to balance the pressure with that of the first chamber 102.

[0061] Furthermore, in this embodiment, the number of circles of air holes 212 is three circles, and the number of air holes 212 in the three circles is equal and is 16-20. The multiple air holes 212 in the outermost circle correspond one-to-one to the multiple air holes 212 in the middle circle, and the multiple air holes 212 in the middle circle correspond one-to-one to the multiple air holes 212 in the innermost circle. The line connecting the centers of the three corresponding air holes 212 located in the outermost circle, the middle circle and the innermost circle is an arc line, and the apertures of the three air holes 212 gradually decrease from the outside to the inside. This arrangement can make the gas-phase crystal growth component that passes through the multiple air holes 212 from the first chamber 102 and enters the second chamber 104 produce a swirl effect close to the outer wall of the second annular portion 220, so that the gas-phase crystal growth component can reach the gap 106 more quickly and evenly to balance the pressure of the two chambers, thereby reducing the flow rate of the gas-phase crystal growth component in the gap 106.

[0062] The shape and orientation of the pores 212 can also be set according to actual needs. In this embodiment, the pores 212 are tilted toward the seed crystal 110. Furthermore, the aperture of the pores 212 gradually decreases in the direction close to the seed crystal 110. The pores 212 are tilted toward the seed crystal 110, which can make the vapor-phase crystal growth components reach the gap 106 faster after passing through the pores 212, thereby increasing the pressure increase rate of the second chamber 104. The gradually decreasing aperture of the pores 212 has a pressurizing effect, which can further increase the pressure increase rate of the second chamber 104. At the same time, the top of the second annular portion 220 is provided with a chamfered corner 222 near the outer periphery of the second chamber 104, so that the vapor-phase crystal growth components in the second chamber 104 can reach the gap 106 more smoothly, thereby achieving pressure balance between the first chamber 102 and the second chamber 104.

[0063] By arranging multiple circles of air holes 212 around the axis of the crucible 100 on the annular guide plate 200, the air holes 212 are inclined toward the seed crystal 110 and the aperture gradually decreases, so that the gas-phase growth components in the first chamber 102 can pass through the air holes 212 while rising into the second chamber 104 and quickly reach the gap 106 between the edge of the seed crystal 110 and the top of the annular guide plate 200, thereby quickly balancing the pressure in the first chamber 102 and the second chamber 104, reducing the flow rate of the gas-phase growth components in the gap 106, and allowing the silicon carbide crystal 400 to grow evenly at the edge and center of the seed crystal 110, thereby ensuring the quality of the silicon carbide crystal 400. Second embodiment

[0064] The overall structure, working principle and technical effects of the apparatus for growing high-quality silicon carbide crystals provided in this embodiment are basically the same as those of the first embodiment, and the difference lies in the specific scheme of the pressure equalization structure.

[0065] 3 , in this embodiment, the pressure-equalizing structure includes silicon carbide powder 300 placed in the second chamber 104. This structure does not require the air holes 212 to be formed in the annular guide plate 200. Instead, the silicon carbide powder 300 is placed in the first chamber 102 while a relatively small amount of silicon carbide powder 300 is placed in the second chamber 104. In this way, while the silicon carbide powder 300 in the first chamber 102 is heated and sublimated to form a vapor-phase growth component, which flows upward to the seed crystal 110 to grow the silicon carbide crystal 400, the silicon carbide powder 300 in the second chamber 104 is also heated and sublimated to form a vapor-phase growth component (see FIG. 2 for details, where the dashed line with an arrow in the figure indicates the flow path of the vapor-phase growth component). As a result, the pressure in the second chamber 104 increases simultaneously with the pressure in the first chamber 102, thereby minimizing the pressure difference between the first chamber 102 and the second chamber 104 and achieving a certain pressure equilibrium. This reduces the flow rate of the vapor-phase growth component in the first chamber 102 at the gap 106, ensuring that the growth rates of the silicon carbide crystal 400 at the edge and center of the seed crystal 110 are as similar as possible. This allows the silicon carbide crystal 400 to grow uniformly at all parts of the seed crystal 110, avoiding defects such as "concave interfaces" and improving the growth quality of the silicon carbide crystal 400.

[0066] In summary, the apparatus for growing high-quality silicon carbide crystals provided in the first and second embodiments of the present invention each include a crucible 100 and an annular guide plate 200. A seed crystal 110 for growing a silicon carbide crystal 400 is disposed on the top wall of the crucible 100. The annular guide plate 200 is disposed within the crucible 100. The bottom end of the annular guide plate 200 is connected to the side wall of the crucible 100, and the top end extends toward the seed crystal 110, with a gap 106 between the annular guide plate 200 and the edge of the seed crystal 110. The annular guide plate 200, the seed crystal 110, the side walls of the crucible 100, and the bottom wall of the crucible 100 collectively form a first chamber 102. The annular guide plate 200, the seed crystal 110, the side walls of the crucible 100, and the top wall of the crucible 100 collectively form a second chamber 104. The first chamber 102 and the second chamber 104 are connected via the gap 106. The annular guide plate 200 is provided with a pressure equalizing structure for balancing the pressures in the first chamber 102 and the second chamber 104. By providing this pressure equalizing structure on the annular guide plate 200, the pressure difference between the first chamber 102 and the second chamber 104 can be effectively reduced, making the pressures in the two chambers as close as possible. This effectively reduces the flow rate of the vapor-phase crystal growth components in the gap 106 between the top of the annular guide plate 200 and the edge of the seed crystal 110, thereby making the growth rate of the silicon carbide crystal 400 at the edge of the seed crystal 110 as close as possible to the growth rate of the silicon carbide crystal 400 in the center of the seed crystal 110. This avoids defects such as a "concave interface" in the silicon carbide crystal 400 on the seed crystal 110 and improves the growth quality of the silicon carbide crystal 400. Third embodiment

[0067] This embodiment provides a method for growing high-quality silicon carbide crystals, which is based on the apparatus of the first embodiment or the second embodiment and specifically includes the following steps:

[0068] Put silicon carbide powder 300 into the crucible 100;

[0069] The crucible 100 is evacuated and then filled with an inert gas;

[0070] Heating the crucible 100 to raise the internal temperature of the crucible 100 to 2000-2600° C.

[0071] The crucible 100 is evacuated again to reduce the internal pressure of the crucible 100 to 0.01-4E3 Pa;

[0072] The silicon carbide powder 300 sublimates and begins to grow a silicon carbide crystal 400 on the seed crystal 110;

[0073] After the silicon carbide crystal 400 has grown for 10-300 hours, the crucible 100 is refilled with inert gas to increase the pressure inside the crucible 100 to 5E3-1E5 Pa;

[0074] After the growth of the silicon carbide crystal 400 is completed, the heating of the crucible 100 is stopped. After the temperature inside the crucible 100 drops to room temperature, the silicon carbide crystal 400 is taken out of the crucible 100.

[0075] The rate of vacuuming and filling is controlled by a mechanical pump, a butterfly valve, and a flow meter. When placing silicon carbide powder 300 in crucible 100, if the apparatus is based on the first embodiment, silicon carbide powder 300 only needs to be placed in first chamber 102. If the apparatus is based on the second embodiment, silicon carbide powder 300 needs to be placed in both first chamber 102 and second chamber 104. Fourth embodiment

[0076] This embodiment provides a silicon carbide crystal 400 , which is prepared using the method for growing high-quality silicon carbide crystals provided in the third embodiment and has the characteristics of few defects and high quality. Fifth embodiment

[0077] Referring to FIG. 4 , the apparatus for growing high-quality silicon carbide crystals provided by the present invention is improved relative to the first embodiment in that:

[0078] The crucible 100 is provided with a plurality of concentration adjustment holes 108 , which are located on the side or upper portion of the second chamber 104 ;

[0079] In this embodiment, considering that the saturation concentrations of gas phase components such as Si and Si2C are relatively high in the early stages of crystal growth, a significantly silicon-rich growth gas phase component is formed, which is not conducive to the high-quality growth of silicon carbide crystal 400. The presence of concentration adjustment through-hole 108 allows excess silicon-rich components to overflow from crucible 100, thereby regulating the carbon-silicon ratio of the growth gas phase components within the crucible, which is conducive to improving the growth quality of silicon carbide crystal 400.

[0080] At the same time, the concentration adjustment through hole 108 also has a drainage function, guiding the crystal growth gas phase components to flow upward, thereby facilitating the formation of the silicon carbide crystal 400. Sixth embodiment

[0081] 5 , the apparatus for growing high-quality silicon carbide crystals provided by the present invention is improved relative to the first embodiment in that:

[0082] The first annular portion 210 includes two layers of sub-annular portions 214, with pores 212 distributed on the two layers of sub-annular portions 214. During heating, the silicon carbide crystal growth gas phase components flow from bottom to top through the two layers of sub-annular portions 214. The sub-annular portion 214 on the lower layer has pores 212 with larger pore diameters than the sub-annular portion 214 on the upper layer.

[0083] It is easy for those skilled in the art to understand that the upper and lower sub-annular portions 214 in this embodiment may not be directly connected, for example, the upper sub-annular portion 214 is connected to the second annular portion 220, and the lower sub-annular portion 214 is connected to the side wall of the crucible 100.

[0084] The technical solution of this embodiment is to balance the distribution of the concentration of the growth gas phase components based on the flow rate. Specifically, the edge of the annular guide plate 200, that is, the position of the first annular portion 210, is more susceptible to heat and has a higher temperature. Therefore, the flow rate of the growth gas phase components is faster, which is not conducive to the balance of the concentration of the growth gas phase components. Therefore, two layers of sub-annular portions 214 are provided, and the apertures of the pores 212 are gradually reduced from bottom to top to provide additional resistance to the faster-flowing growth gas phase components, thereby balancing the distribution of the concentration of the growth gas phase components in the crucible 100.

[0085] It is easy to understand for those skilled in the art that, as a further preferred embodiment of the present invention, the sub-annular portion 214 may be multi-layered, such as 3 to 5 layers;

[0086] The aperture of the pores 212 of the uppermost sub-annular portion 214 can be sufficiently small, even approaching zero, to form sufficient resistance.

[0087] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with this technical field within the technical scope disclosed in the present invention should be covered by the scope of protection of the present invention.

Claims

1. A device for growing high-quality silicon carbide crystals, It is characterized in that include: A crucible (100), wherein a top wall of the crucible (100) is provided with a seed crystal (110) for growing a silicon carbide crystal (400); An annular guide plate (200), the annular guide plate (200) being arranged in the crucible (100), the bottom end of the annular guide plate (200) being connected to the side wall of the crucible (100), the top end of the annular guide plate (200) extending toward the seed crystal (110) and having a gap (106) between the top end and the edge of the seed crystal (110), the annular guide plate (200), the seed crystal (110), the side wall of the crucible (100), and the bottom wall of the crucible (100) together forming a A first chamber (102), the annular guide plate (200), the seed crystal (110), the side wall of the crucible (100) and the top wall of the crucible (100) together form a second chamber (104), the first chamber (102) and the second chamber (104) are connected via the gap (106), and the annular guide plate (200) is provided with a pressure equalizing structure for balancing the pressure of the first chamber (102) and the second chamber (104); The pressure equalizing structure comprises an air hole (212) opened on the annular guide plate (200), the air hole (212) connecting the first chamber (102) and the second chamber (104), the annular guide plate (200) comprising a first annular portion (210) and a second annular portion (220) connected at an angle, one end of the first annular portion (210) away from the second annular portion (220) is connected to the inner wall of the crucible (100), one end of the second annular portion (220) away from the first annular portion (210) extends toward the seed crystal (110), and the air hole (212) is opened in the first annular portion (210).

2. The device for growing high-quality silicon carbide crystal according to claim 1, It is characterized in that The number of the air holes (212) is multiple, and the multiple air holes (212) are arranged in one or more circles around the axis of the crucible (100).

3. The device for growing high-quality silicon carbide crystal according to claim 2, It is characterized in that The plurality of air holes (212) are arranged in a plurality of circles around the axis of the crucible (100); the plurality of circles of air holes (212) are spaced apart in the radial direction of the crucible (100); and any two adjacent circles of air holes (212) are staggered in the radial direction of the crucible (100).

4. The apparatus for growing high-quality silicon carbide crystal according to claim 1, It is characterized in that The first annular portion (210) is in the shape of a plate and is perpendicular to the axis of the crucible (100); the outer peripheral wall of the first annular portion (210) is connected to the side wall of the crucible (100); the second annular portion (220) is in the shape of a hollow cylinder or a hollow cone; the bottom end of the second annular portion (220) is connected to the inner peripheral wall of the first annular portion (210), and the top end extends toward the seed crystal (110).

5. The apparatus for growing high-quality silicon carbide crystal according to claim 1, It is characterized in that The pores (212) are arranged obliquely toward the seed crystal (110), and the aperture of the pores (212) gradually decreases in a direction approaching the seed crystal (110).

6. The apparatus for growing high-quality silicon carbide crystal according to claim 1, It is characterized in that The pressure equalization structure includes silicon carbide powder (300) placed in the second chamber (104).

7. The apparatus for growing high-quality silicon carbide crystal according to claim 1, It is characterized in that At least one concentration adjustment through hole (108) is provided on the crucible (100) at the periphery of the second chamber (104).

8. The apparatus for growing high-quality silicon carbide crystal according to claim 1, It is characterized in that The first annular portion (210) comprises a plurality of sub-annular portions (214) distributed vertically, and the air holes (212) are distributed on each sub-annular portion (214).

9. The apparatus for growing high-quality silicon carbide crystal according to claim 8, It is characterized in that Along the transmission direction of the crystal growth component, several layers of the sub-annular portions (214) have pores (212) with gradually smaller diameters.

10. A method for growing high quality silicon carbide crystals, It is characterized in that The device for growing high-quality silicon carbide crystal according to claim 1 comprises: Putting silicon carbide powder (300) into the crucible (100); The crucible (100) is evacuated and then filled with an inert gas; Heating the crucible (100) so that the temperature inside the crucible (100) rises to 2000-2600° C.; The crucible (100) is evacuated again to reduce the internal pressure of the crucible (100) to 0.01-4E3 Pa; The silicon carbide powder (300) sublimates and begins to grow silicon carbide crystals (400) on the seed crystals (110); After the silicon carbide crystal (400) has grown for 10-300 hours, the crucible (100) is refilled with an inert gas to increase the internal pressure of the crucible (100) to 5E3-1E5 Pa; After the growth of the silicon carbide crystal (400) is completed, the heating of the crucible (100) is stopped, and after the temperature inside the crucible (100) drops to room temperature, the silicon carbide crystal (400) is taken out of the crucible (100).

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