Silicon carbide crystal growth device capable of reducing wrappage

Abstract

The invention discloses a silicon carbide crystal growth device capable of reducing inclusions, comprising: an upper crucible defining a crystal growth chamber with an open bottom, the top wall of the crystal growth chamber being provided with a seed crystal; a crucible body; the first graphite filtering piece is in lap joint with the first annular step, the second graphite filtering piece is in lap joint with the second annular step, silicon carbide powder is laid below the first graphite filtering piece, and an inert particle filling layer is laid between the first graphite filtering piece and the second graphite filtering piece; a first airflow through hole is formed in the middle of the first graphite filter part, a second airflow through hole is formed in the middle of the second graphite filter part, and the diameter of the first airflow through hole is smaller than that of the second airflow through hole. According to the silicon carbide crystal growth device disclosed by the invention, the first graphite filtering piece, the inert particle filling layer and the second graphite filtering piece are sequentially arranged in the vertical direction, so that the inclusion defect of the silicon carbide crystal ingot can be reduced.

Description

Technical Field

[0001] The invention relates to the field of silicon carbide crystal growth, and in particular to a silicon carbide crystal growth device capable of reducing inclusions. Background Art

[0002] Silicon carbide (SiC) single crystal material has the characteristics of wide band gap, high critical electric field, high thermal conductivity, and high carrier saturation drift velocity. It is an important third-generation semiconductor material and is suitable for use as a substrate for power / RF devices.

[0003] At present, the industrial growth of silicon carbide crystals mainly uses the physical vapor transport (PVT) method. In the process of growing silicon carbide single crystals by physical vapor transport, on the one hand, due to the presence of various impurities in the silicon carbide raw materials, these impurities will sublimate into the gas phase with the raw materials at high temperatures, and gather on the growth surface of the seed crystal and in the crystal to form inclusions of impurity particles; on the other hand, due to the low melting point characteristics of the silicon component, it will evaporate and sublimate preferentially. The preferential evaporation and sublimation characteristics of silicon will cause the silicon carbide raw materials to gradually loosen and carbonize. During the further growth of silicon carbide, the airflow will carry these carbon particles into the growth surface of the seed crystal, thereby forming carbon inclusions in the silicon carbide single crystal. Therefore, how to reduce the inclusions in silicon carbide single crystals is a technical problem that technicians in this field urgently need to solve. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention is to propose a silicon carbide crystal growth device that can reduce inclusions by providing a first graphite filter, an inert particle filling layer and a second graphite filter arranged in sequence in the upper and lower directions, and the purified silicon carbide gas enters the crystal growth chamber and is transported to the seed crystal growth surface for crystallization, which is beneficial to reducing the inclusion defects of the silicon carbide ingot.

[0005] A silicon carbide crystal growth device capable of reducing inclusions according to an embodiment of the present invention comprises: an upper crucible, wherein the upper crucible defines a crystal growth chamber with an open bottom, and a seed crystal is arranged on the top wall of the crystal growth chamber; a crucible body, wherein the crucible body defines a powder cavity with an open top, the upper crucible is threadedly connected to the crucible body, and the inner wall of the crucible body is provided with a first annular step and a second annular step, and the second annular step is located above the first annular step; a first graphite filter and a second graphite filter, wherein the first graphite filter is overlapped on the first annular step, and the second graphite filter is overlapped on the second annular step, silicon carbide powder is laid below the first graphite filter, and an inert particle filling layer is laid between the first graphite filter and the second graphite filter, a first airflow hole is arranged in the middle of the first graphite filter, and a second airflow hole is arranged in the middle of the second graphite filter, the first graphite filter and the second graphite filter are arranged concentrically, and the diameter of the first airflow hole is smaller than the diameter of the second airflow hole.

[0006] According to the silicon carbide crystal growth device capable of reducing inclusions in the embodiment of the present invention, a first graphite filter, an inert particle filling layer and a second graphite filter arranged in sequence in the upper and lower directions are arranged, and the purified silicon carbide gas enters the crystal growth chamber and is transported to the seed crystal growth surface for crystallization, which is beneficial to reducing the inclusion defects of the silicon carbide ingot. At the same time, the first graphite filter and the second graphite filter adjacent to each other along the axial direction of the crucible body, the first graphite filter located below has a smaller diameter of the first air flow hole, and the annular area of ​​the first graphite filter is larger, which can block more inclusions from the silicon carbide powder. In addition, by concentrically arranging the first graphite filter and the second graphite filter, it can be ensured that the atmosphere rises more smoothly. The first graphite filter, the inert particle filling layer and the second graphite filter can continuously and progressively block the inclusions, which can effectively filter the generated tiny inclusions, reduce the inclusion content in the silicon carbide single crystal, and thus improve the quality of the silicon carbide single crystal.

[0007] In some embodiments of the present invention, the first graphite filter element is further provided with a plurality of first through holes, and the plurality of first through holes are arranged around the first air flow hole, the diameter of the first air flow hole is 70mm-80mm, the diameter of the first through hole is 2mm-3mm, and the hole spacing between two adjacent first through holes is 2mm-3mm.

[0008] In some embodiments of the present invention, the first graphite filter element is further provided with a plurality of transition holes, the plurality of transition holes are arranged in a ring shape and are located between the first air flow holes and the plurality of the first through holes, and the diameter of the transition holes is 4 mm-6 mm.

[0009] In some embodiments of the present invention, the second graphite filter element is further provided with a plurality of second through holes, the plurality of second through holes are arranged around the second air flow through hole, the diameter of the second air flow through hole is 100 mm-110 mm, and the diameter of the second through hole is 1.5 mm-2.5 mm.

[0010] In some embodiments of the present invention, the inert particle filling layer includes at least one of tungsten, tantalum, molybdenum, niobium, hafnium, chromium, vanadium, zirconium and titanium.

[0011] In some embodiments of the present invention, the height of the inert particle filling layer is 20 mm-25 mm.

[0012] In some embodiments of the present invention, the silicon carbide crystal growth device also includes: an annular lining ring, which is arranged in the crucible body and located between the first graphite filter and the second graphite filter, and the surface of the annular lining ring is provided with a tantalum carbide coating.

[0013] In some embodiments of the present invention, the thickness of the tantalum carbide coating is 20 μm-60 μm.

[0014] In some embodiments of the present invention, the silicon carbide crystal growth device also includes: a tantalum mesh, which is located between the first graphite filter and the inner wall of the crucible body, and the tantalum mesh includes a first mesh body and a second mesh body, the first mesh body is formed in a ring shape, and the first mesh body is in contact with the inner circumferential wall of the crucible body, the second mesh body is circular and connected to the bottom end of the first mesh body, and the second mesh body is in contact with the inner bottom wall of the crucible body.

[0015] In some embodiments of the present invention, the particle size of the silicon carbide powder is 8-40 mesh, the specification of the tantalum mesh is 60-100 mesh, and the thickness of the tantalum mesh is 1mm-3mm.

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

[0017] Figure 1 is a schematic structural diagram of a silicon carbide crystal growth device according to an embodiment of the present invention;

[0018] Figure 2 is a schematic structural diagram of a first graphite filter according to an embodiment of the present invention;

[0019] Figure 3 is a schematic structural diagram of a second graphite filter according to an embodiment of the present invention;

[0020] Figure 4is a schematic structural diagram of a first graphite filter according to another embodiment of the present invention;

[0021] Figure 5 is a schematic diagram of a top view of a first mesh body according to an embodiment of the present invention;

[0022] Figure 6 is a schematic diagram of a top view of the structure of a second mesh body according to an embodiment of the present invention;

[0023] Figure 7 yes Figure 6 Schematic diagram of the front view of the second mesh body.

[0024] Reference numerals:

[0025] Silicon carbide crystal growth apparatus 100;

[0026] Upper crucible 10; crucible cover 11; graphite ring 12; guide inclined hole 121; seed crystal 13; crystal growth chamber 14;

[0027] Crucible body 20; first annular step 21; second annular step 22;

[0028] A first graphite filter 30; a first air flow hole 31; a first through hole 32; a transition hole 33;

[0029] A second graphite filter 40; a second air flow hole 41; a second through hole 42;

[0030] Silicon carbide powder 50;

[0031] Inert particle filling layer 60;

[0032] annular backing ring 70;

[0033] Tantalum mesh 80; first mesh body 81; second mesh body 82. DETAILED DESCRIPTION

[0034] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0035] The disclosure below provides many different embodiments or examples to implement different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific processes and examples of materials, but those of ordinary skill in the art can be aware of the applicability of other processes and / or the use of other materials.

[0036] Reference below Figure 1-Figure 7 A silicon carbide crystal growth apparatus 100 capable of reducing inclusions according to an embodiment of the present invention is described.

[0037] Reference Figure 1 As shown, a silicon carbide crystal growth device 100 capable of reducing inclusions according to an embodiment of the present invention may include: an upper crucible 10 , a crucible body 20 , a first graphite filter 30 , and a second graphite filter 40 .

[0038] Reference Figure 1 As shown, the upper crucible 10 defines a crystal growth chamber 14 with an open bottom, and a seed crystal 13 is arranged on the top wall of the crystal growth chamber 14. For example, the upper crucible 10 includes a crucible cover 11 and a graphite ring 12. The seed crystal 13 is pasted on the bottom of the crucible cover 11. The graphite ring 12 is connected to the crucible cover 11 by threads, and the crystal growth chamber 14 is defined between the crucible cover 11 and the graphite ring 12.

[0039] Reference Figure 1 As shown, the crucible body 20 defines a powder cavity with an open top, the upper crucible 10 is threadedly connected to the crucible body 20, the inner wall of the crucible body 20 is provided with a first annular step 21 and a second annular step 22, the second annular step 22 is located above the first annular step 21, the first graphite filter 30 is overlapped on the first annular step 21, and the second graphite filter 40 is overlapped on the second annular step 22. It can be understood that by providing the first annular step 21 and the second annular step 22, the installation of the first graphite filter 30 and the second graphite filter 40 is facilitated.

[0040] Reference Figure 1As shown, silicon carbide powder 50 is laid under the first graphite filter 30, wherein the particle size of the silicon carbide powder 50 can be 5-60 meshes. The silicon carbide powder 50 is the raw material for growing silicon carbide single crystals by the PVT method. The particle size, crystal form, purity and other states of the powder will directly affect the quality of the silicon carbide single crystal, thereby affecting the electrical properties of the silicon carbide single crystal and even the quality of the subsequent devices. In addition, the sublimation of the powder during the crystal growth process and the transportation of gas-phase silicon carbide in the powder also have an important influence on the quality of the silicon carbide single crystal.

[0041] Reference Figure 1 As shown, an inert particle filling layer 60 is laid between the first graphite filter 30 and the second graphite filter 40. The inert particle filling layer 60 has the function of adsorbing and filtering carbon inclusions. For example, the particle size of the inert particles can be 0.5mm-5mm. A first airflow hole 31 is provided in the middle of the first graphite filter 30, and a second airflow hole 41 is provided in the middle of the second graphite filter 40. The first graphite filter 30 and the second graphite filter 40 are concentrically arranged, and the diameter of the first airflow hole 31 is smaller than the diameter of the second airflow hole 41. The bottom of the graphite ring 12 is threadedly connected to the top of the crucible body 20, and the bottom surface of the graphite ring 12 abuts against the second graphite filter 40 to fix the second graphite filter 40.

[0042] It should be noted that when loading, the silicon carbide powder 50 can be first loaded into the bottom of the crucible body 20 until the loading height of the silicon carbide powder 50 reaches the first annular step 21, and then the first graphite filter 30 is installed on the first annular step 21, and then an inert particle filling layer 60 is arranged above the first graphite filter 30 until the height of the inert particle filling layer 60 reaches the second annular step 22, and then the second graphite filter 40 is installed on the second annular step 22, and finally the crucible 10 is installed to complete the loading.

[0043] It can be understood that, according to the silicon carbide crystal growth device 100 capable of reducing inclusions, the first graphite filter 30, the inert particle filling layer 60 and the second graphite filter 40 arranged in sequence in the up-down direction are provided, and the purified silicon carbide gas enters the crystal growth chamber 14 and is transported to the growth surface of the seed crystal 13 for crystallization, which is beneficial to reducing the inclusion defects of the silicon carbide ingot. At the same time, the first graphite filter 30 and the second graphite filter 40 adjacent to each other along the axial direction of the crucible body 20, the first graphite filter 30 located below the first graphite filter 30 and the second graphite filter 40 are arranged in sequence in the up-down direction. The diameter of the air flow hole 31 is relatively small, and the annular surface area of ​​the first graphite filter element 30 is relatively large, so that more tiny inclusions from the silicon carbide powder 50 can be blocked, and by arranging the first graphite filter element 30 and the second graphite filter element 40 concentrically, the atmosphere can be ensured to rise more smoothly. The first graphite filter element 30, the inert particle filling layer 60 and the second graphite filter element 40 can continuously and progressively block the inclusions, and can effectively filter the generated tiny inclusions, reduce the inclusion content in the silicon carbide single crystal, and thus improve the quality of the silicon carbide single crystal.

[0044] Reference Figure 1 As shown, the graphite ring 12 has a diverting inclined hole 121, the central axis of the diverting inclined hole 121 coincides with the central axis of the crucible body 20, and in the direction from bottom to top, the hole wall of the diverting inclined hole 121 extends toward the direction close to the central axis of the crucible body 20, and the angle between the hole wall of the diverting inclined hole 121 and the horizontal plane is 50°-70°. In other words, the angle between the hole wall of the diverting inclined hole 121 and the horizontal plane can take any value between 50°-70°. It should be noted that the inclined hole wall of the diverting inclined hole 121 cooperates with the second graphite filter 40 to effectively block the powder source surface from radiating heat to the corresponding part of the crucible cover 11, which is conducive to reducing the radial temperature gradient at the crucible cover 11, and the temperature on the crystal growth surface is more uniform, which can make the surface morphology of the growing crystal flatter on the one hand, thereby improving the utilization rate of the silicon carbide single crystal, and on the other hand, it is conducive to reducing the thermal stress in the silicon carbide single crystal to improve the quality of the crystal.

[0045] In some embodiments of the present invention, reference Figure 1 and Figure 2As shown, the first graphite filter element 30 is also provided with a plurality of first through holes 32, and the plurality of first through holes 32 are arranged around the first air flow hole 31, the diameter of the first air flow hole 31 is 70mm-80mm, the diameter of the first through hole 32 is 2mm-3mm, and the hole spacing between two adjacent first through holes 32 is 2mm-3mm. In other words, the diameter of the first air flow hole 31 can take any value between 70mm and 80mm, for example, the diameter of the first air flow hole 31 can take a value of 71mm, 73mm, 75mm, 77mm, 78mm or 79mm; the diameter of the first through hole 32 can take any value between 2mm and 3mm, for example, the diameter of the first through hole 32 can take a value of 2.1mm, 2.3mm, 2.4mm, 2.6mm, 2.8mm or 2.9mm; the hole spacing between two adjacent first through holes 32 can take any value between 2mm and 3mm, for example, the hole spacing between two adjacent first through holes 32 can take a value of 2.1mm, 2.3mm, 2.4mm, 2.7mm, 2.8mm or 2.9mm.

[0046] It can be understood that by making the diameter of the first air flow hole 31 between 70mm-80mm, on the one hand, the diameter of the first air flow hole 31 is not too large, so as to ensure the annular area of ​​the first graphite filter 30 and improve the blocking effect on the inclusions; on the other hand, the diameter of the first air flow hole 31 can be made not too small, so as to ensure the flow of atmosphere through the first air flow hole 31 and reduce the impact on the flow of atmosphere toward the seed crystal; by making the diameter of the first through hole 32 between 2mm-3mm, on the one hand, the diameter of the first through hole 32 can be made not too large, so as to ensure the filtering effect on the inclusions, and on the other hand, the diameter of the first through hole 32 can be made not too small, which is beneficial to ensure the stability of the atmosphere flow inside the crucible; by making the hole spacing between two adjacent first through holes 32 between 2mm-3mm, it is beneficial to further improve the filtering performance of the first graphite filter 30.

[0047] In some embodiments of the present invention, reference Figure 4 As shown, the first graphite filter 30 is also provided with a plurality of transition holes 33, which are arranged in an annular manner and are located between the first air flow holes 31 and the plurality of first through holes 32, and the diameter of the transition holes 33 is 4 mm-6 mm. In other words, the diameter of the transition holes 33 can be any value between 4 mm and 6 mm. It can be understood that by providing the transition holes 33, the flow area of ​​the first graphite filter 30 can be gradually increased from the outside to the inside in the radial direction. Under the premise of ensuring the filtering capacity of the first graphite filter 30, the influence of the first graphite filter 30 on the flow of the atmosphere in the crucible can be further reduced, which is conducive to ensuring the stability of the thermal field.

[0048] In some embodiments of the present invention, reference Figure 1 and Figure 3 As shown, the second graphite filter element 40 is further provided with a plurality of second through holes 42, and the plurality of second through holes 42 are arranged around the second air flow hole 41, and the diameter of the second air flow hole 41 is 100 mm-110 mm. In other words, the second air flow hole 41 can take any value between 100 mm and 110 mm, for example, the second air flow hole 41 can take a value of 101 mm, 103 mm, 105 mm, 106 mm, 107 mm, 108 mm or 109 mm; the diameter of the second through hole 42 is 1.5 mm-2.5 mm. In other words, the diameter of the second through hole 42 can take any value between 1.5 mm and 2.5 mm, for example, the diameter of the second through hole 42 can be 1.5 mm, 1.7 mm, 1.9 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm or 2.5 mm. It can be understood that by making the diameter of the second air flow hole 41 between 100mm-110mm and the diameter of the second through hole 42 between 1.5mm-2.5mm, on the one hand, the filtering capacity of the second graphite filter 40 can be guaranteed, and on the other hand, it is conducive to ensuring the stability of the gas flow in the crucible body 20, thereby minimizing the impact on the transport of the sublimation atmosphere of the silicon carbide powder 50 and improving the quality of the silicon carbide single crystal.

[0049] In some embodiments of the present invention, reference Figure 1 As shown, the inert particle filling layer 60 includes at least one of tungsten, tantalum, molybdenum, niobium, hafnium, chromium, vanadium, zirconium and titanium. Alternatively, the inert particle filling layer 60 includes one of tungsten, tantalum, molybdenum, niobium, hafnium, chromium, vanadium, zirconium and titanium. Alternatively, the inert particle filling layer 60 is composed of a plurality of tungsten, tantalum, molybdenum, niobium, hafnium, chromium, vanadium, zirconium and titanium. Optionally, the inert particles can be high-purity tantalum particles (for example, with a purity of 99.99%), and the tantalum particles are 2mmx2mm in size. The high-purity tantalum particles can completely bury the silicon carbide powder 50 during filling, on the one hand, ensuring that the particles are not too small to cause gas path blockage, and on the other hand, ensuring that the particles are not too large to affect the filtering effect. Of course, the material type of the inert material particles here is only an example, but any inert particles that will not affect the silicon carbide crystal growth process are within the scope of protection of the present invention.

[0050] In some embodiments of the present invention, reference Figure 1As shown, the height of the inert particle filling layer 60 is 20mm-25mm. In other words, the distance between the top surface and the bottom surface of the inert particle filling layer 60 can take any value in the range of 20mm-25mm. For example, the height of the inert particle filling layer 60 can be 21mm, 22mm, 23mm, 24mm or 25mm. It can be understood that by making the height of the inert particle filling layer 60 20mm-25mm, on the one hand, it can be ensured that the height of the inert particle filling layer 60 is not too high, which is conducive to reducing costs, and on the other hand, it can be ensured that the height of the inert particle filling layer 60 is not too low, thereby ensuring the filtering effect of the inert particle filling layer 60. Optionally, the charging height of the silicon carbide powder 50 can be 60mm-90mm.

[0051] In some embodiments of the present invention, reference Figure 1 As shown, the silicon carbide crystal growth device 100 also includes an annular liner ring 70, which is arranged in the crucible body 20 and between the first graphite filter 30 and the second graphite filter 40, and the surface of the annular liner ring 70 is provided with a tantalum carbide coating. The annular liner ring 70 is a hard graphite part. The second annular step 22 is defined by the top surface of the annular liner ring 70 and the inner peripheral wall of the crucible body 20, and the diameter of the second graphite filter 40 is slightly larger than the diameter of the first graphite filter 30, so as to facilitate installation.

[0052] It can be understood that the tantalum carbide coating itself has good chemical stability and corrosion resistance. Therefore, providing a tantalum carbide coating on the annular liner ring 70 can prevent the gas entering the inert particle filling layer 60 from directly corroding the crucible body 20, which is beneficial to reducing the possibility of corrosion particles of the crucible body 20 entering the silicon carbide crystal and causing inclusion defects. At the same time, the annular liner ring 70 is a graphite annular structure with a simple structure. Compared with depositing the tantalum carbide coating on the entire crucible body 20, depositing the tantalum carbide coating on the annular liner ring 70 has a simple process and low cost.

[0053] In some embodiments of the present invention, referring to Figure 1 As shown, the thickness of the tantalum carbide coating is 20 μm-60 μm. In other words, the thickness of the tantalum carbide coating can be any value between 20 μm and 60 μm. For example, the thickness of the tantalum carbide coating can be 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 50 μm or 60 μm. It can be understood that by setting the thickness of the annular backing ring 70 to 20 μm-60 μm, it is beneficial to ensure the comprehensive performance of the annular backing ring 70. Optionally, the tantalum carbide coating can be made by chemical vapor deposition, and has good adhesion to the annular backing ring 70 and is not easy to fall off.

[0054] In some embodiments of the present invention, reference Figure 1As shown, the silicon carbide crystal growth device 100 also includes: a tantalum mesh 80, which is located between the first graphite filter 30 and the inner wall of the crucible body 20, and the tantalum mesh 80 includes a first mesh body 81 and a second mesh body 82. The first mesh body 81 is formed in a ring shape, and the first mesh body 81 is in contact with the inner peripheral wall of the crucible body 20. The second mesh body 82 is circular and connected to the bottom end of the first mesh body 81, and the second mesh body 82 is in contact with the inner bottom wall of the crucible body 20. It should be noted that the first mesh body 81 and the second mesh body 82 are separate parts, and the texture of the tantalum mesh 80 is relatively hard. When installing the tantalum mesh 80, the first mesh body 81 can be first installed in the bottom of the crucible body 20, and then the second mesh body 82 can be installed, and the second mesh body 82 can be in contact with the inner peripheral wall of the crucible body 20. Among them, the mesh of the tantalum mesh 80 can be formed in a circular, elliptical or polygonal shape.

[0055] It can be understood that the tantalum mesh 80 has the advantages of high purity, excellent corrosion resistance, and good mechanical properties. During the crystal growth process, the crucible body 20 will be severely corroded. By arranging the tantalum mesh 80 in the crucible body 20, the corrosion particles on the inner wall of the crucible body 20 can be blocked from entering the crystal growth atmosphere, which is beneficial to further reduce the inclusion defects of the silicon carbide crystals, thereby improving the crystal growth quality.

[0056] It should be noted that during the crystal growth process, some corroded carbon particles in the crucible body 20 will be deposited on the tantalum mesh 80, making the mesh holes smaller or even blocking the mesh holes, but it does not affect the ability of the tantalum mesh 80 to isolate the corroded particles. Therefore, the tantalum mesh 80 can be reused, which is beneficial to reduce production costs.

[0057] In some embodiments of the present invention, reference Figure 1 As shown, the particle size of the silicon carbide powder 50 is 8-40 mesh, the specification of the tantalum mesh 80 is 60-100 mesh, and the thickness of the tantalum mesh 80 is 1mm-3mm. In other words, the particle size of the silicon carbide powder 50 can be any value between 8-40 mesh, the specification of the tantalum mesh 80 can be any value between 60-100 mesh, and the thickness of the tantalum mesh 80 can be any value between 1mm-3mm. For example, in one example, the specification of the tantalum mesh 80 is 60 mesh, and the thickness of the tantalum mesh 80 is 2mm. It can be understood that by making the particle size of the silicon carbide powder 50 8-40 mesh and the specification of the tantalum mesh 80 60-100 mesh, the silicon carbide powder 50 can be prevented from contacting the surrounding wall of the crucible during loading, which is beneficial to reduce the corrosion of the crucible body 20 during the crystal growth process. At the same time, by making the thickness of the tantalum mesh 80 1mm-3mm, it is beneficial to reduce costs while ensuring the structural strength of the tantalum mesh 80.

[0058] Please refer to the following Figure 1 as well as Figure 3-Figure 7The silicon carbide crystal growth device 100 capable of reducing inclusions of the present invention is described in detail. Of course, it can be understood that the following description is intended to explain the present invention, but cannot be used as a limitation of the present invention.

[0059] Reference Figure 1 As shown, a silicon carbide crystal growth device 100 capable of reducing inclusions according to an embodiment of the present invention includes: an upper crucible 10 , a crucible body 20 , a first graphite filter 30 , a second graphite filter 40 and a tantalum mesh 80 .

[0060] Reference Figure 1 As shown, the upper crucible 10 includes a crucible cover 11 and a graphite ring 12 , a seed crystal 13 is pasted on the bottom of the crucible cover 11 , the graphite ring 12 is connected to the crucible cover 11 by threads, and a crystal growth chamber 14 is defined between the crucible cover 11 and the graphite ring 12 .

[0061] Reference Figure 1 As shown, the crucible body 20 defines a powder cavity with an open top, the upper crucible 10 is threadedly connected to the crucible body 20, the inner wall of the crucible body 20 is provided with a first annular step 21 and a second annular step 22, the second annular step 22 is located below the first annular step 21, the first graphite filter 30 is overlapped on the first annular step 21, the second graphite filter 40 is overlapped on the second annular step 22, the annular liner 70 is provided in the crucible body 20 and is located between the first graphite filter 30 and the second graphite filter 40, the surface of the annular liner 70 is provided with a tantalum carbide coating, and the thickness of the tantalum carbide coating is 30μm.

[0062] Reference Figure 1 as well as Figure 5-Figure 7 As shown, silicon carbide powder 50 is laid below the first graphite filter 30, wherein the particle size of the silicon carbide powder 50 can be 8-40 meshes, and the height of the silicon carbide powder 50 can be 80 mm. The tantalum mesh 80 is located between the first graphite filter 30 and the inner wall of the crucible body 20, and the tantalum mesh 80 includes a first mesh body 81 and a second mesh body 82. The first mesh body 81 is formed in an annular shape, and the first mesh body 81 is attached to the inner peripheral wall of the crucible body 20. The second mesh body 82 is circular and connected to the bottom end of the first mesh body 81. The second mesh body 82 is attached to the inner bottom wall of the crucible body 20. The specification of the tantalum mesh 80 is 60 meshes, and the thickness of the tantalum mesh 80 is 1.5 mm.

[0063] Reference Figure 1 As shown, an inert particle filling layer 60 is laid between the first graphite filter element 30, the second graphite filter element 40 and the annular liner ring 70. The inert particle filling layer 60 has the function of adsorbing and filtering carbon inclusions. The inert particle filling layer 60 is specifically composed of tantalum particles. The size of the tantalum particles is 2mmx2mm. The height of the inert particle filling layer 60 is 25mm.

[0064] Reference Figure 1 and Figure 3 As shown, the first graphite filter 30 is provided with a first air flow hole 31, a transition hole 33 and a first through hole 32. The first air flow hole 31 is located in the middle of the first graphite filter 30, and a plurality of first through holes 32 are arranged around the first air flow hole 31. A plurality of transition holes 33 are arranged in a ring and are located between the first air flow hole 31 and the plurality of first through holes 32. Specifically, the diameter of the first air flow hole 31 is 75 mm, the first through hole 32 is 11 circles, the diameter of the first through hole 32 is 2 mm, the diameter of the transition hole 33 is 4 mm, and the hole spacing is 2 mm.

[0065] Reference Figure 1 and Figure 2 As shown, a second air flow hole 41 and a plurality of second through holes 42 are provided in the middle of the second graphite filter element 40. The second air flow hole 41 is located in the middle of the second graphite filter element 40, and a plurality of second through holes 42 are arranged around the second air flow hole 41. The diameter of the second air flow hole 41 is 105 mm, the diameter of the second through hole 42 can be 1.6 mm, and the hole spacing is 1 mm.

[0066] The quality of the silicon carbide single crystals obtained in the examples and comparative examples was characterized, and the characterization results are shown in the following table.

[0067] Silicon carbide crystal performance parameters Example Comparative Example Crystal thickness (mm) 23 24 Polymorphic none 2％ Resistivity (ohm*cm) 0.02 0.024 <![CDATA[Microtubule density (ea / cm 2 )]]> 0.05 0.5 Visual observation of the cumulative area of ​​carbon inclusions (observation under strong light) ≤0.02％ ≤0.5％ Cumulative area of ​​hexagonal holes (observed under strong light) ≤0.02％ ≤0.4％ <![CDATA[Total dislocation density (ea / cm 2 )]]> 2000 5000

[0068] It can be seen from the above table that the cumulative area of ​​carbon inclusions in the silicon carbide single crystal grown in this embodiment is greatly reduced compared with the comparative example.

[0069] It can be understood that the silicon carbide crystal growth device 100 capable of reducing inclusions according to the embodiment of the present invention is provided with a first graphite filter 30, an inert particle filling layer 60 and a second graphite filter 40 arranged in sequence in the up-down direction, the first air flow hole 31 of the first graphite filter 30 located at the bottom has a smaller diameter, and the annular surface area of ​​the first graphite filter 30 is larger, which can block more tiny inclusions from the silicon carbide powder 50, and by arranging the first graphite filter 30 and the second graphite filter 40 concentrically, it can be ensured that the atmosphere is The rise is more stable, the first graphite filter 30, the inert particle filling layer 60 and the second graphite filter 40 can continuously and progressively block the inclusions, and can effectively filter the generated tiny inclusions, reduce the inclusion content in the silicon carbide single crystal, and thus improve the quality of the silicon carbide single crystal. In addition, by arranging a tantalum mesh 80 in the crucible body 20, the carbon inclusions on the crucible body 20 can be blocked from entering the crystal growth atmosphere, which is beneficial to reduce the possibility of corrosion particles on the crucible body 20 entering the silicon carbide crystal to cause inclusion defects, thereby improving the crystal growth quality.

[0070] Other structures and operations of the silicon carbide crystal growth apparatus 100 according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail here.

[0071] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0072] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0073] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0074] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0075] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0076] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A silicon carbide crystal growth device capable of reducing inclusions, characterized in that: include: An upper crucible, wherein the upper crucible defines a crystal growth chamber with an open bottom, and a seed crystal is disposed on a top wall of the crystal growth chamber; A crucible body, wherein the crucible body defines a powder cavity with an open top, the upper crucible is threadedly connected to the crucible body, and the inner wall of the crucible body is provided with a first annular step and a second annular step, wherein the second annular step is located above the first annular step; A first graphite filter element and a second graphite filter element, the first graphite filter element is overlapped on the first annular step, the second graphite filter element is overlapped on the second annular step, silicon carbide powder is laid under the first graphite filter element, an inert particle filling layer is laid between the first graphite filter element and the second graphite filter element, a first air flow hole is provided in the middle of the first graphite filter element, a second air flow hole is provided in the middle of the second graphite filter element, the first graphite filter element and the second graphite filter element are concentrically arranged, and the diameter of the first air flow hole is smaller than the diameter of the second air flow hole.

2. The silicon carbide crystal growth device capable of reducing inclusions according to claim 1, characterized in that: The first graphite filter element is also provided with a plurality of first through holes, which are arranged around the first air flow hole, the diameter of the first air flow hole is 70mm-80mm, the diameter of the first through hole is 2mm-3mm, and the hole spacing between two adjacent first through holes is 2mm-3mm.

3. The silicon carbide crystal growth device capable of reducing inclusions according to claim 2, characterized in that: The first graphite filter element is also provided with a plurality of transition holes, which are arranged in a ring shape and are located between the first air flow holes and the plurality of the first through holes, and the diameter of the transition holes is 4 mm-6 mm.

4. The silicon carbide crystal growth device capable of reducing inclusions according to claim 2, characterized in that: The second graphite filter element is also provided with a plurality of second through holes, and the plurality of second through holes are arranged around the second air flow through hole, the diameter of the second air flow through hole is 100 mm-110 mm, and the diameter of the second through hole is 1.5 mm-2.5 mm.

5. The silicon carbide crystal growth device capable of reducing inclusions according to claim 1, characterized in that: The inert particle filling layer includes at least one of tungsten, tantalum, molybdenum, niobium, hafnium, chromium, vanadium, zirconium and titanium.

6. The silicon carbide crystal growth device capable of reducing inclusions according to claim 5, characterized in that: The height of the inert particle filling layer is 20 mm-25 mm.

7. The silicon carbide crystal growth device capable of reducing inclusions according to claim 1, characterized in that: Also includes; An annular liner ring is arranged in the crucible body and between the first graphite filter element and the second graphite filter element, and a tantalum carbide coating is arranged on the surface of the annular liner ring.

8. The silicon carbide crystal growth device capable of reducing inclusions according to claim 7, characterized in that: The thickness of the tantalum carbide coating is 20 μm-60 μm.

9. The silicon carbide crystal growth device capable of reducing inclusions according to any one of claims 1 to 8, characterized in that: Also includes: Tantalum mesh, the tantalum mesh is located between the first graphite filter and the inner wall of the crucible body, the tantalum mesh includes a first mesh body and a second mesh body, the first mesh body is formed into a ring shape, the first mesh body is in contact with the inner circumferential wall of the crucible body, and the second mesh body is in contact with the inner bottom wall of the crucible body.

10. The silicon carbide crystal growth device capable of reducing inclusions according to claim 9, characterized in that: The particle size of the silicon carbide powder is 8-40 mesh, the specification of the tantalum mesh is 60-100 mesh, and the thickness of the tantalum mesh is 1mm-3mm.

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