Method for manufacturing silicon carbide ingot

Abstract

The present invention includes the steps of: arranging a silicon carbide raw material and a seed crystal in a reaction vessel having an inner space; primarily elevating the temperature of the inner space by a heating means surrounding the reaction vessel; secondarily elevating the temperature of the inner space by the heating means while decompressing the inner space; inducing growth of a silicon carbide ingot under the reduced pressure condition after the pressure reduction of the inner space is completed; cooling the temperature of the inner space to room temperature, wherein the inner space includes an upper part in which the seed crystal is disposed and a lower part in which the silicon carbide raw material is disposed and in the secondarily temperature elevating step, a difference between the upper temperature of the inner space and the lower temperature of the inner space is maintained at 50℃ to 100℃.

Description

Method for manufacturing silicon carbide ingot The present invention relates to a method for manufacturing a silicon carbide ingot. Silicon carbide (SiC) boasts excellent heat resistance, mechanical strength, and radiation resistance, allowing for production on large-diameter substrates. Furthermore, SiC boasts superior physical strength and chemical resistance, a large energy band gap, and high electron saturation drift velocity and voltage resistance. Therefore, it is widely used in semiconductor devices requiring high power, efficiency, voltage, and capacity, as well as in abrasives, bearings, and refractory plates. Silicon carbide is manufactured through various methods, including heat treatment or electrical current application of carbon raw materials such as silicon carbide waste. Conventional methods include the Acheson process, reaction sintering, pressureless sintering, and chemical vapor deposition (CVD). However, these methods suffer from the problem of residual carbon raw materials, which can act as impurities and degrade the thermal, electrical, and mechanical properties of silicon carbide. For example, Japanese Patent Application Laid-Open No. 2002-326876 discloses a method for manufacturing a silicon carbide precursor by reacting it at high temperature under an inert gas such as argon (Ar) after a heat treatment process to polymerize or cross-link a silicon source and a carbon source. However, this process has the problem of high manufacturing cost and uneven powder size because it requires high-temperature heat treatment at 1,800°C to 2,100°C under vacuum or inert gas conditions. Moreover, wafers used in the solar cell and semiconductor industries are manufactured by growing silicon ingots in crucibles made of graphite or other materials. This manufacturing process generates significant amounts of waste slurry containing silicon carbide, as well as silicon carbide waste adsorbed to the inner walls of the crucible. However, this waste has traditionally been landfilled, leading to environmental problems and significant disposal costs. The present invention provides a method for manufacturing a silicon carbide ingot having a low occurrence of defects, an excellent growth rate, and improved crystal quality. A method for manufacturing a silicon carbide ingot according to the present invention comprises the steps of arranging a silicon carbide raw material and seed crystals in a reaction vessel having an internal space, the step of first heating the temperature of the internal space by a heating means surrounding the reaction vessel, the step of secondarily heating the temperature of the internal space by the heating means while depressurizing the internal space, the step of inducing growth of a silicon carbide ingot under the depressurized pressure when the depressurization of the internal space is completed, and the step of cooling the temperature of the internal space to room temperature, wherein the internal space includes an upper portion where the seed crystals are arranged and a lower portion where the silicon carbide raw material is arranged, and in the second heating step, a difference between the temperature of the upper portion of the internal space and the temperature of the lower portion of the internal space is maintained at 50°C to 100°C. In one embodiment of the present invention, the first heating step may be performed until the depressurization of the internal space begins. In one embodiment of the present invention, the second heating step may be performed until the depressurization of the internal space is completed. In one embodiment of the present invention, the upper temperature of the internal space in the second heating step may be 2,200°C to 2,250°C. In one embodiment of the present invention, the lower temperature of the internal space in the second heating step may be 2,250°C to 2,350°C. In one embodiment of the present invention, in the step of inducing growth of the silicon carbide ingot, the difference between the upper temperature of the internal space and the lower temperature of the internal space can be maintained at 50°C to 200°C. In one embodiment of the present invention, in the first temperature raising step, the difference between the upper temperature of the internal space and the lower temperature of the internal space can be maintained at 40°C to 60°C. In one embodiment of the present invention, the heating means may include a plurality of coils that move in the height direction of the reaction vessel and generate an induced current in the reaction vessel. In one embodiment of the present invention, the distance between the coil and the reaction vessel may be 60 mm to 600 mm. In one embodiment of the present invention, the diameter of each of the plurality of coils may be 5 mm to 40 mm, and the spacing between the plurality of coils may be 5 mm to 30 mm. In one embodiment of the present invention, the induced current of the coil is 1 × 10 4 A to 2 × 10 6 It could be A. In one embodiment of the present invention, in the second heating step, the center position of the coil according to the following equation 1 can satisfy 40% to 60%. [Formula 1] Coil center position (%) = (H1 / H0) × 100 In the above equation 1, H0 is the total height of the reaction vessel, and H1 is the height of the reaction vessel at a position corresponding to the center of the plurality of coils based on the height direction of the reaction vessel. In one embodiment of the present invention, the center position of the coil according to the above formula 1 can satisfy 53% to 57%. In one embodiment of the present invention, in the step of inducing growth of the silicon carbide ingot, the center position of the coil according to the above formula 1 can satisfy 20% to 50%. In the method for manufacturing a silicon carbide ingot according to the present invention, in the step of increasing the temperature of the internal space by a heating means while depressurizing the internal space, the difference between the upper temperature of the internal space and the lower temperature of the internal space is maintained at 50°C to 100°C. By controlling the process temperature in this way, the phenomenon of seed loss due to silicon-rich gas sublimating in the early stage of growth of the silicon carbide ingot can be minimized. In addition, in the method for manufacturing a silicon carbide ingot according to the present invention, in the step of inducing growth of the silicon carbide ingot, the difference between the upper temperature of the internal space and the lower temperature of the internal space can be maintained at 50°C to 200°C. After the ratio of carbon and silicon is stabilized in this way, by adjusting the process temperature to a different process temperature range from the previous process temperature, the deposition rate of silicon carbide gas on the seed crystal increases, and the growth rate of the silicon carbide ingot can be improved. By the method for manufacturing a silicon carbide ingot according to the present invention, a silicon carbide ingot substantially free of defects and having improved crystal quality, a wafer manufactured therefrom, etc. can be provided. Figure 1 is a flowchart schematically showing a manufacturing method according to the present invention. Figure 2 is a flowchart specifically illustrating step S10. Figure 3 is a flowchart specifically illustrating step S20. Figure 4 is a flowchart specifically illustrating step S50. FIGS. 5 and 6 schematically illustrate a cross-section of a silicon carbide ingot manufacturing device for manufacturing a silicon carbide ingot according to one embodiment of the invention. Figure 7 schematically illustrates the position of the coil at step S30. Figure 8 schematically illustrates the position of the coil at step S40. Figure 9 is a photograph of the surface of a silicon carbide ingot according to Example 1 taken using an optical microscope. Figure 10 is a photograph of the surface of a silicon carbide ingot according to Comparative Example 1 taken using an optical microscope. Figure 11 is a photograph of the surface of a silicon carbide ingot according to Comparative Example 2 taken using an optical microscope. Fig. 12 is a photograph of the surface of a silicon carbide wafer sample according to Example 1 taken using an optical microscope. Figure 13 is a photograph of the surface of a silicon carbide wafer sample according to Comparative Example 1 taken using an optical microscope. Figure 14 is a photograph of the surface of a silicon carbide wafer sample according to Comparative Example 2 taken using an optical microscope. The structural or functional descriptions of the embodiments disclosed in this specification or application are merely illustrative for the purpose of explaining embodiments according to the technical idea of ​​the present invention, and the embodiments according to the technical idea of ​​the present invention can be implemented in various forms other than the embodiments disclosed in this specification or application, and the technical idea of ​​the present invention is not construed as being limited to the embodiments described in this specification or application. When a component is referred to as "including" in this specification or application, unless otherwise specifically stated, this does not exclude other components, but rather implies the inclusion of additional components. Furthermore, all numerical ranges indicating physical properties, dimensions, etc. of the components described in this specification or application should be understood to be modified by the term "about" in all cases unless otherwise specified. Furthermore, "ppm" in this specification or application refers to weight basis. The description of "A and / or B" in this specification or application means "A, B, or A and B." In addition, when it is said that a certain component is "connected" to another component, this includes not only the case where it is "directly connected" but also the case where it is "connected with another component in between." In addition, the meaning of B being located on A means that B is located in direct contact with A or that B is located on A with another layer located therebetween, and is not limited to being interpreted as being located in contact with the surface of A. In addition, the singular expression is interpreted to include the singular or plural as interpreted in the context unless specifically stated otherwise. In addition, each embodiment may be combined with each other, as long as they are not technically incompatible with each other. Hereinafter, the present invention will be described in detail. A method for manufacturing a silicon carbide ingot according to the present invention comprises the steps of arranging a silicon carbide raw material and seed crystals in a reaction vessel having an internal space, the step of first heating the temperature of the internal space by a heating means surrounding the reaction vessel, the step of secondarily heating the temperature of the internal space by the heating means while depressurizing the internal space, the step of inducing growth of a silicon carbide ingot under the depressurized pressure when the depressurization of the internal space is completed, and the step of cooling the temperature of the internal space to room temperature, wherein the internal space includes an upper portion where the seed crystals are arranged and a lower portion where the silicon carbide raw material is arranged, and in the second heating step, a difference between the temperature of the upper portion of the internal space and the temperature of the lower portion of the internal space is maintained at 50°C to 100°C. FIG. 1 is a flowchart schematically showing a manufacturing method according to the present invention, FIG. 2 is a flowchart specifically showing step S10, and FIGS. 5 and 6 schematically show a cross-section of a silicon carbide ingot manufacturing device for manufacturing a silicon carbide ingot according to one embodiment of the invention. Referring to FIGS. 1, 2, 5 and 6, the manufacturing method includes a step of placing silicon carbide raw material (20) and seed crystals (30) (S10). The above step S10 may include a step (S11) of arranging the silicon carbide raw material (20) and the seed crystal (30) to face each other, a step (S12) of sealing the internal space of the reaction vessel (10), a step (S13) of arranging an insulating material (40) surrounding the reaction vessel (10), and a step of arranging a heating means (60) outside the reaction vessel (10) and the insulating material (40). The silicon carbide raw material (20) of the above step S11 may include silicon carbide. The above silicon carbide raw material (20) may include α-phase silicon carbide and / or β-phase silicon carbide. The above silicon carbide raw material (20) may include a silicon carbide single crystal and / or a silicon carbide polycrystal. The above silicon carbide raw material (20) may further contain unwanted impurities in addition to silicon carbide. The above silicon carbide raw material (20) may further contain a carbonaceous material such as graphite as an impurity. The carbonaceous material may be derived from a graphite crucible, etc. The carbonaceous material may be included in the silicon carbide raw material (20) in an amount of about 1 wt% to about 60 wt%. The carbonaceous material may be included in the silicon carbide raw material (20) in an amount of about 2 wt% to about 60 wt%. The carbonaceous material may be included in the silicon carbide raw material (20) in an amount of about 5 wt% to about 60 wt%. The carbonaceous material may be included in the silicon carbide raw material (20) in an amount of about 5 wt% to about 50 wt%. The carbonaceous material may be included in the silicon carbide raw material (20) in an amount of about 50 wt% or less. The carbonaceous material may be included in the silicon carbide raw material (20) in an amount of about 45 wt% or less. The carbon-based material may be included in the silicon carbide raw material (20) in an amount of about 40 wt% or less. The carbon-based material may be included in the silicon carbide raw material (20) in an amount of about 1 wt% to about 50 wt%. The carbon-based material may be included in the silicon carbide raw material (20) in an amount of about 5 wt% to about 45 wt%. The carbon-based material may be included in the silicon carbide raw material (20) in an amount of about 10 wt% to about 40 wt%. The carbon-based material may be included in the silicon carbide raw material (20) in an amount of about 10 wt% to about 35 wt%. The carbon-based material may be included in the silicon carbide raw material (20) in an amount of about 10 wt% to about 30 wt%. The carbon-based material may be included in the silicon carbide raw material (20) in an amount of about 10 wt% to about 20 wt%. The silicon carbide raw material (20) may further include free silicon as an impurity. The free silicon may be derived from a silicon substrate and / or a silicon component. The silicon component may be a component used in semiconductor equipment, such as a focus ring. The free silicon may be included in the silicon carbide raw material in an amount of about 0.01 wt% to about 10 wt%. The above silicon carbide raw material (20) may further include metal impurities. The metal impurities may be selected from the group consisting of lithium, boron, sodium, aluminum, phosphorus, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, strontium, zirconium, molybdenum, tin, barium, tungsten, or lead. The content of the metal impurity may be about 0.1 ppm to 13 ppm based on the total weight of the silicon carbide raw material (20). The content of the metal impurity may be about 0.3 ppm to 12 ppm. The content of the metal impurity may be about 0.5 ppm to 8 ppm. The content of the metal impurity may be about 0.8 ppm to 10 ppm. The content of the metal impurity may be about 1 ppm to 6 ppm. The content of the metal impurity may be about 0.1 ppm to 5 ppm. The content of the metal impurity may be about 0.5 ppm to 3 ppm. The content of the metal impurity may be about 0.5 ppm to 2 ppm. The above silicon carbide raw material (20) may further include non-metallic impurities. The non-metallic impurities may be selected from the group consisting of fluorine, nitrogen, chlorine, or phosphorus. The content of the non-metallic impurities may be about 0.01 ppm to 30 ppm based on the total weight of the silicon carbide raw material (20). The content of the non-metallic impurities may be about 0.3 ppm to 20 ppm. The content of the non-metallic impurities may be about 0.5 ppm to 15 ppm. The content of the non-metallic impurities may be about 1 ppm to 15 ppm. The content of the non-metallic impurities may be about 3 ppm to 13 ppm. The content of the non-metallic impurities may be about 1 ppm to 10 ppm. The content of the non-metallic impurities may be about 5 ppm to 15 ppm. The content of the non-metallic impurities may be about 5 ppm to 12 ppm. The above silicon carbide raw material (20) may contain about 30 wt% or more of particles having a particle size of about 100 μm or more. The above silicon carbide raw material (20) may contain about 50 wt% or more of particles having a particle size of about 100 μm or more. The above silicon carbide raw material (20) may contain about 70 wt% or more of particles having a particle size of about 100 μm or more. The silicon carbide raw material (20) may contain about 30 wt% or more of particles having a particle size of about 1 mm or more. The silicon carbide raw material (20) may contain about 50 wt% or more of particles having a particle size of about 1 mm or more. The silicon carbide raw material (20) may contain about 70 wt% or more of particles having a particle size of about 1 mm or more. The silicon carbide raw material (20) may contain about 30 wt% or more of particles having a particle size of about 10 mm or more. The silicon carbide raw material (20) may contain about 50 wt% or more of particles having a particle size of about 10 mm or more. The silicon carbide raw material (20) may contain about 70 wt% or more of particles having a particle size of about 10 mm or more. Here, a sphere having the same volume as the volume of the particle is assumed, and the diameter of the sphere is defined as the particle diameter. The above silicon carbide raw material (20) may be derived from a substrate comprising silicon carbide. The above silicon carbide raw material (20) may be derived from a wafer comprising silicon carbide as a whole. The above silicon carbide raw material (20) may be derived from a silicon carbide layer deposited on a substrate such as silicon. The above silicon carbide raw material (20) may be derived from a silicon carbide single crystal ingot. The silicon carbide single crystal ingot may be generated during the manufacturing process and discarded due to defects. The above silicon carbide raw material (20) may be derived from a silicon carbide polycrystal. The above silicon carbide raw material (20) may be derived from a silicon carbide sintered body. The silicon carbide sintered body may be formed by sintering silicon carbide powder. The silicon carbide sintered body may be a component included in semiconductor manufacturing equipment. The above silicon carbide raw material (20) may be derived from a graphite component including a silicon carbide layer. The graphite component may include a crucible or the like for forming a silicon carbide ingot. The above silicon carbide raw material (20) may be derived from a component of a semiconductor device including a silicon carbide layer. The silicon carbide layer may be formed by depositing silicon carbide on the surface of a silicon component or the like through a chemical vapor deposition (CVD) process. The above silicon carbide raw material (20) may have a lump shape. The above silicon carbide raw material (20) may have a plate shape. The above silicon carbide raw material (20) may have a block shape. One or more silicon carbide blocks may be included in the crucible body (11). The apparent volume of the silicon carbide block may be about 1 ㎤ or more. The apparent volume of the silicon carbide block may be about 5 ㎤ or more. The apparent volume of the silicon carbide block may be about 10 ㎤ or more. The apparent volume of the silicon carbide block may be about 20 ㎤ or more. The apparent volume of the silicon carbide block may be about 100 ㎤ or more. The apparent volume of the silicon carbide block may be about 1,000 ㎤ or more. The apparent volume of the silicon carbide block may be about 5,000 ㎤ or more. The apparent volume of the silicon carbide block may be about 1 ㎥ or less. The apparent volume of the silicon carbide block may be smaller than the volume of the internal space of the crucible body (11). The apparent volume may be a volume measured based on the outer shape of the silicon carbide block. The apparent volume may be a volume measured on the assumption that there are no pores at all within the silicon carbide block. The sum of the volume of silicon carbide within the silicon carbide block and the volume of pores within the silicon carbide block may be the apparent volume. The silicon carbide block may have a columnar shape, such as a circular column or a polygonal column. The silicon carbide block may have a polyhedral shape. The silicon carbide block may have a plate shape. The silicon carbide block may have a horn shape, such as a cone or a polygonal pyramid. The silicon carbide block may have a donut shape. The silicon carbide block may have a shape in which a portion is cut. The above silicon carbide block may be single crystal or polycrystalline. The above silicon carbide block may be a sintered body. That is, the above silicon carbide block may be formed into a block shape by sintering silicon carbide particles or the like. The above silicon carbide block may be formed by depositing silicon carbide by chemical vapor deposition. The above silicon carbide block may be formed by depositing silicon carbide by physical vapor deposition. The above silicon carbide block may include α-phase silicon carbide or β-phase silicon carbide. The above silicon carbide block may have high thermal conductivity. The thermal conductivity of the silicon carbide block may be about 10 W / mK or more. The thermal conductivity of the silicon carbide block may be about 20 W / mK or more. The thermal conductivity of the silicon carbide block may be about 30 W / mK or more. The thermal conductivity of the silicon carbide block may be about 50 W / mK or more. The thermal conductivity of the silicon carbide block may be about 70 W / mK or more. The thermal conductivity of the silicon carbide block may be about 100 W / mK or more. The thermal conductivity of the silicon carbide block may be about 110 W / mK or more. The upper limit of the thermal conductivity of the silicon carbide block may be about 2,000 W / mK. The silicon carbide block may have anisotropic thermal conductivity. The silicon carbide block may be arranged to have a thermal conductivity of about 10 W / mK or more in a horizontal direction. The silicon carbide block may be arranged to have a thermal conductivity of about 20 W / mK or more in a horizontal direction. The silicon carbide block may be arranged to have a thermal conductivity of about 30 W / mK or more in a horizontal direction. The silicon carbide block may be arranged to have a thermal conductivity of about 40 W / mK or more in a horizontal direction. The silicon carbide block may be arranged to have a thermal conductivity of about 50 W / mK or more in a horizontal direction. The silicon carbide block may be arranged to have a thermal conductivity of about 70 W / mK or more in a horizontal direction. The silicon carbide block may be arranged to have a thermal conductivity of about 100 W / mK or more in a horizontal direction. The above silicon carbide block may be arranged to have a thermal conductivity of about 110 W / mK or more in the horizontal direction. The upper limit of the thermal conductivity of the silicon carbide block in the horizontal direction may be about 2,000 W / mK. Since the silicon carbide block has a thermal conductivity in the above range, heat generated from the crucible body (31) can be efficiently transferred to the center of the internal space of the crucible body (11). Accordingly, the temperature gradient in the horizontal direction within the crucible body (11) can be minimized. The diameter of the silicon carbide block may be substantially the same as the inner diameter of the crucible body (11). The silicon carbide block may almost completely fill the lower portion of the crucible body (11). At least a portion of the outer surface of the silicon carbide block may be in direct contact with the inner surface of the crucible body (11). Of the outer surface of the silicon carbide block, a portion in contact with the inner surface of the crucible body (11) may be about 20% or more. When the crucible body (11) and the silicon carbide block are partially in contact, heat generated in the crucible body (11) can be easily transferred to the silicon carbide block. The seed (31) in the above step S11 can be placed at the upper part of the internal space and can be placed facing the silicon carbide raw material (20). The above seed (30) may be any one of the wafers to which an off-angle is applied, which is an angle selected in the range of 0 to 8 degrees with respect to the (0001) plane. The above seed crystal (30) may be a substantially single-crystal 4H silicon carbide (SiC) ingot with minimal defects or polymorphic inclusions. The above seed crystal (30) may be substantially composed of 4H silicon carbide (SiC). The seed well (30) may have a diameter of 4 inches or more, 5 inches or more, or 6 inches or more. The seed well (30) may have a diameter of 4 to 12 inches, 4 to 10 inches, or 6 to 8 inches. The seed (30) may be bonded to a seed holder (not shown). The seed holder may include graphite. The seed holder may be made of graphite. The seed holder may include anisotropic graphite and / or isotropic graphite. The seed holder (not shown) may be made of anisotropic graphite and / or isotropic graphite. The seed holder may have high thermal conductivity. The seed holder may have high thermal conductivity in a horizontal direction. The seed holder may have a thermal conductivity of about 100 W / mK or more in at least one direction. The seed holder may have a thermal conductivity of about 110 W / mK or more in at least one direction. The seed holder may have a thermal conductivity of about 120 W / mK or more in at least one direction. The seed holder may have a thermal conductivity of about 130 W / mK or more in at least one direction. The seed holder may have a thermal conductivity of about 140 W / mK or more in at least one direction. The seed holder may have a thermal conductivity of about 150 W / mK or more in at least one direction. The crucible cover (12) and the seed holder may be formed integrally with each other. The crucible cover (12) and the seed holder may be formed of graphite. The crucible cover (12) and the seed holder may have a thermal conductivity of about 100 W / mK or more in at least one direction among the horizontal directions. The crucible cover (12) and the seed holder may have a thermal conductivity of about 110 W / mK or more in at least one direction among the horizontal directions. The crucible cover (12) and the seed holder may have substantially the same thermal conductivity according to the direction. The seed (30) and the seed holder may be bonded to each other by an adhesive layer (not shown). The adhesive layer may include a carbide such as a graphite filler and a phenol resin. The adhesive layer may have a low porosity. The seed (30) may be arranged so that the C-side faces downward. The above step S12 can seal the internal space of the reaction vessel (10). The above reaction vessel (10) may include a crucible body (11) and a crucible cover (12). The crucible body (11) may accommodate the silicon carbide raw material (20). The crucible body (11) may include graphite. The crucible body (11) may be made of graphite. The crucible body (11) may be a graphite crucible. The crucible body (11) may be a conductor. The crucible body (11) may be heated by the resistive heat generated by the heating means (60). The density of the crucible body (11) may be 1.70 g / cm3 to 1.90 g / cm3. The density of the crucible body (11) may be 1.75 g / cm3 to 1.90 g / cm3. The density of the crucible body (11) may be 1.75 g / cm3 to 1.85 g / cm3. The crucible cover (12) may be placed on the upper portion of the crucible body (11) and may cover the entrance of the crucible body (11). The crucible cover (12) may have a circular plate shape. The crucible cover (12) may entirely cover the entrance of the crucible body (11). The crucible cover (12) may have a shape corresponding to the entrance of the crucible body (11). The thickness of the crucible cover (12) may be about 10 mm to about 50 mm. The thickness of the crucible cover (12) may be about 15 mm to about 50 mm. The thickness of the crucible cover (12) may be about 15 mm to about 45 mm. The density of the crucible cover (12) may be 1.70 g / cm3 to 1.90 g / cm3. The density of the crucible cover (12) may be 1.75 g / cm3 to 1.90 g / cm3. The density of the crucible cover (12) may be 1.75 g / cm3 to 1.85 g / cm3. The crucible cover (12) may include graphite. The crucible cover (12) may be substantially made of graphite. The crucible cover (12) may be applied in a form that covers the entire opening of the crucible body (11). The above crucible cover (12) may be applied to cover a portion of the opening of the crucible body (11) or may include a through hole (not shown). The crucible body (11) and the crucible cover (12) may be assembled to form the reaction vessel (10). The above step S13 can place an insulating material (40) surrounding the reaction vessel (10). The above insulation (40) can affect the temperature gradient of the reaction vessel (10) or the internal space of the reaction vessel (10) in a colon growth atmosphere. The insulation (40) may include graphite insulation. The insulation (40) may include rayon-based graphite felt or pitch-based graphite felt. The above insulation (40) may include a first insulation material that wraps the crucible body (11), and a second insulation material that wraps the crucible cover (12). The first insulation material may form a gap of 0 mm to 10 mm with the crucible body (11). The first insulation material may form a gap of 0 mm to 5 mm with the crucible body (11). The first insulation material may form a gap of 0 mm to 3 mm with the crucible body (11). The first insulation material may form a gap of 1 mm to 3 mm with the crucible body (11). The gap may serve as a buffer according to a change in the volume of the crucible body (11). The second insulation material may be formed with a gap of 0 mm to 10 mm from the crucible cover (12). The second insulation material may be formed with a gap of 0 mm to 5 mm from the crucible cover (12). The second insulation material may be formed with a gap of 0 mm to 3 mm from the crucible cover (12). The second insulation material may be formed with a gap of 1 mm to 3 mm from the crucible cover (12). The gap may serve as a buffer according to a change in the volume of the crucible cover (12). At least a portion of the second insulating material may have a void space. By having the void space in the second insulating material, heat generated from the crucible can be smoothly dissipated. The above insulating material (40) may have a density of 0.12 g / cc to 0.30 g / cc. The above insulating material (40) may have a density of 0.13 g / cc to 0.25 g / cc. The above insulating material (40) may have a density of 0.14 g / cc to 0.20 g / cc. When the above ranges are satisfied, the quality of the silicon carbide ingot can be improved, and the crystal growth atmosphere can be controlled during the growth process of the silicon carbide ingot, so that a silicon carbide ingot of better quality can be grown. The above insulating material (40) may have a porosity of 73 vol% to 95 vol%. The above insulating material (40) may have a porosity of 76 vol% to 93 vol%. The above insulating material (40) may have a porosity of 81 vol% to 91 vol%. When the above ranges are satisfied, the frequency of crack occurrence in the manufactured silicon carbide ingot may be further reduced. The above insulating material (40) may have a compressive strength of 0.21 Mpa or more. The above insulating material (40) may have a compressive strength of 0.49 Mpa or more. The above insulating material (40) may have a compressive strength of 0.78 Mpa or more. The above insulating material (40) may have a compressive strength of 3 Mpa or less. The above insulating material (40) may have a compressive strength of 2.5 Mpa or less. When the above ranges are satisfied, the thermal and mechanical stability is excellent, and the probability of ash generation is reduced, so that a silicon carbide ingot of better quality can be manufactured. The thickness of the above insulation (40) may be 20 mm or more. The thickness of the above insulation (40) may be 30 mm or more. The thickness of the above insulation (40) may be 150 mm or less. The thickness of the above insulation (40) may be 120 mm or less. The thickness of the above insulation (40) may be 80 mm or less. When the above range is satisfied, the insulation effect can be sufficiently obtained without unnecessary waste of the above insulation. The above insulating material (40) may have a density of 0.12 g / cc to 0.30 g / cc and a porosity of 72 vol% to 90 vol%. When the above ranges are satisfied, the shape of the silicon carbide ingot being manufactured can be suppressed from growing concavely or excessively convexly, and the phenomenon of polymorph quality deteriorating or cracks occurring in the silicon carbide ingot can be reduced. In the above step S14, a heating means (60) can be placed outside the reaction vessel (10) and the insulation material (40). The reaction vessel (10) or the internal space of the reaction vessel (10) can be heated by the heating means (60). The heating means (60) may be movable in the height direction (Y) of the reaction vessel and may include a plurality of coils (60) that generate an induced current in the reaction vessel (10). The plurality of coils (60) may be formed along the outer circumferential surface of the insulating material (40). The heating means (60) can move substantially parallel to the reaction vessel (10). Accordingly, the relative position between the heating means (60) and the reaction vessel (10) can be changed, so that a temperature gradient in the internal space of the reaction vessel (10) can be induced. In addition, a temperature difference can be generated between the upper temperature (T1) of the internal space and the lower temperature (T2) of the internal space by the heating means (60). The distance (d2) between the coil (60) and the reaction vessel (10) may be 60 mm to 600 mm. The distance (d2) between the coil (60) and the reaction vessel (10) may be 60 mm to 550 mm. The distance (d2) between the coil (60) and the reaction vessel (10) may be 60 mm to 500 mm. The distance (d2) between the coil (60) and the reaction vessel (10) may be 60 mm to 450 mm. The distance (d2) refers to the distance between the outer surface of the reaction vessel (10) and the center point of the coil (60). When the above range is satisfied, the induced current induced by the coil (60) can be efficiently transmitted to the reaction vessel (10), so that the growth rate of the silicon carbide ingot can be improved. The diameter (r) of each of the plurality of coils (60) may be 5 mm to 40 mm, and the spacing (d1) between the plurality of coils (60) may be 5 mm to 30 mm. The diameter (r) of each of the plurality of coils (60) may be 5 mm to 30 mm, and the spacing (d1) between the plurality of coils (60) may be 10 mm to 30 mm. The diameter (r) of each of the plurality of coils (60) may be 5 mm to 20 mm, and the spacing (d1) between the plurality of coils (60) may be 10 mm to 30 mm. The spacing (d1) refers to the distance between the center lines of the coils (60) adjacent to each other at the top and bottom. When the above range is satisfied, the reaction vessel (10) may be uniformly heated, and thus the speed at which silicon carbide gas is deposited on the seed layer (30) may be improved. The induced current of the above coil (60) is 1 × 10 4 A to 2 × 10 6 A may be. The induced current of the above coil (60) is 1.5 × 10 4 A to 2 × 10 6 A may be. The induced current of the above coil (60) is 1.5 × 104 A to 1.5 × 10 6 A may be. The induced current of the above coil (60) is 1 × 10 5 A to 1.5 × 10 6 A may be. When the above range is satisfied, the growth rate of the silicon carbide ingot can be improved while suppressing excessive saturation of the silicon carbide gas at the initial stage of temperature increase. In the above step S10, the reaction vessel (10) and the insulation material (40) may be positioned within the reaction chamber (50). The reaction chamber (50) may be connected to the interior of the reaction chamber (50) and may include a vacuum exhaust device for controlling the vacuum level within the reaction chamber (50). The reaction chamber (50) may be connected to the interior of the reaction chamber (50) and may include a pipe for introducing gas into the interior of the reaction chamber (50) and a mass flow controller for controlling the introduction of the gas. Through these, the flow rate of the inert gas in the step of inducing growth of the silicon carbide ingot and the step of cooling may be controlled. The above manufacturing method includes a first temperature-raising step (S20). The S20 step is a step of raising the temperature of the internal space by the heating means (60) surrounding the reaction vessel (10). Fig. 3 is a flowchart specifically illustrating step S20. Referring to Fig. 3, step S20 may include a step of adjusting to a high vacuum atmosphere (S21), a step of injecting an inert gas into the internal space (S22), and a step of increasing the temperature of the internal space using a heating means (60) (S23). The above step S21 can adjust the internal space of the reaction vessel (10) to a high vacuum atmosphere. The step S21 can reduce the pressure of the internal space to 50 torr or less. The step S21 can reduce the pressure of the internal space to 10 torr or less. The step S21 can reduce the pressure of the internal space to 5 torr or less. The step S21 can reduce the pressure of the internal space to 1 torr to 5 torr. By the step S21, the defect of the silicon carbide ingot can be reduced. The above step S22 may inject an inert gas into the internal space of the reaction vessel (10). By the step S22, the internal space may be substantially controlled to have an inert gas atmosphere. The type of the inert gas may be argon (Ar), helium (He), nitrogen (N2), or a mixed gas thereof. The pressure of the internal space in the step S22 may be 500 torr to 800 torr. The pressure of the internal space in the step S22 may be 600 torr to 800 torr. The pressure of the internal space in the step S22 may be 650 torr to 800 torr. The above step S23 may be a step of first increasing the temperature of the internal space using the heating means (60). The first temperature increasing may be performed until the depressurization of the internal space begins. The first temperature increasing may be performed at a rate of 1 ℃ / min to 10 ℃ / min. The first temperature increasing may be performed at a rate of 3 ℃ / min to 10 ℃ / min. The first temperature increasing may be performed at a rate of 5 ℃ / min to 10 ℃ / min. The step S23 may be performed to increase the temperature so that the lower temperature (T2) of the internal space becomes about 1,500 ℃ to 1,700 ℃. The step S23 may be performed to increase the temperature so that the lower temperature (T2) of the internal space becomes about 1,550 ℃ to 1,700 ℃. The above step S23 can be heated so that the lower temperature (T2) of the internal space becomes about 1,550 ℃ to 1,650 ℃. When the above range is satisfied, the occurrence of polymorphs other than the desired crystal can be prevented, and the growth of the silicon carbide ingot can proceed stably. In the step S23, the difference between the upper temperature (T1) of the internal space and the lower temperature (T2) of the internal space can be maintained at 40 ℃ to 60 ℃. In the step S23, the difference between the upper temperature (T1) of the internal space and the lower temperature (T2) of the internal space can be maintained at 45 ℃ to 60 ℃. In the step S23, the difference between the upper temperature (T1) of the internal space and the lower temperature (T2) of the internal space can be maintained at 45 ℃ to 55 ℃. The above manufacturing method includes a second temperature increasing step (S30). The S30 step is a step of secondarily increasing the temperature of the internal space by the heating means (60) while depressurizing the internal space. The meaning of the second temperature increasing step may mean a temperature increasing step that is distinct from the first temperature increasing step in the S20 step. The S30 step may be performed until the depressurization of the internal space is completed. The S30 step may be a step of depressurizing the pressure of the internal space to reach a growth pressure and increasing the temperature of the internal space to reach a growth temperature. By the S30 step, the ratio of carbon and silicon in the silicon carbide gas may be stabilized. The above S30 step can be decompressed to a growth pressure of 1 torr to 50 torr. The above S30 step can be decompressed to a growth pressure of 1 torr to 30 torr. The above S30 step can be decompressed to a growth pressure of 1 torr to 10 torr. The above S30 step can apply a difference between the upper temperature (T1) of the internal space and the lower temperature (T2) of the internal space by the coil (60). Fig. 7 schematically illustrates the positions of the coils at step S30. Referring to Fig. 7, the plurality of coils (60) can be moved in the height direction of the reaction vessel (10). H0 is the total height of the reaction vessel (10), and H1 refers to the height of the reaction vessel at a position corresponding to the center of the plurality of coils (60) based on the height direction of the reaction vessel (10). The internal space of the reaction vessel (10) corresponding to the center of the plurality of coils (60) may be the maximum heating area. In the above step S30, the upper temperature (T1) of the internal space and the lower temperature (T2) of the internal space can be controlled according to the central position of the plurality of coils (60). In the above step S30, the difference between the upper temperature (T1) of the internal space and the lower temperature (T2) of the internal space can be controlled by adjusting the central position of the plurality of coils (60). The internal space includes an upper portion where the seed crystal (30) is arranged and a lower portion where the silicon carbide raw material (20) is arranged, and in the step S30, the difference between the upper temperature (T1) of the internal space and the lower temperature (T2) of the internal space is maintained at 50°C to 100°C. When the above range is satisfied, the phenomenon of seed crystal loss due to silicon-rich gas sublimated in the early stage of growth of the silicon carbide ingot can be minimized. Accordingly, a silicon carbide ingot and wafer having substantially no defects and improved crystal quality can be manufactured. The above step S30 may be performed at a heating rate of 1°C / min to 5°C / min. The above step S30 may be performed at a heating rate of 2°C / min to 5°C / min. The above step S30 may be performed at a heating rate of 2°C / min to 4°C / min. In the step S30, the upper temperature (T1) of the internal space may be 2,200°C to 2,250°C. In the step S30, the upper temperature (T1) of the internal space may be 2,220°C to 2,250°C. In the step S30, the upper temperature (T1) of the internal space may be 2,225°C to 2,250°C. In the step S30, the upper temperature (T1) of the internal space may be 2,230°C to 2,250°C. In the step S30, the lower temperature (T2) of the internal space may be 2,250°C to 2,350°C. In the step S30, the lower temperature (T2) of the internal space may be 2,270°C to 2,350°C. In the step S30, the lower temperature (T2) of the internal space may be 2,280°C to 2,350°C. In the step S30, the lower temperature (T2) of the internal space may be 2,280°C to 2,320°C. In the above step S30, the center position of the coil (60) according to the following equation 1 can satisfy 40% to 60%. [Formula 1] Coil center position (%) = (H1 / H0) × 100 In the above equation 1, H0 is the total height of the reaction vessel, and H1 is the height of the reaction vessel at a position corresponding to the center of the plurality of coils based on the height direction of the reaction vessel. The center position of the coil (60) according to the above formula 1 can satisfy 41% to 59%, 45% to 59%, 45% to 58%, or 53% to 57%. When the above range is satisfied, the phenomenon of seed crystal loss can be minimized, so that a silicon carbide ingot and wafer having substantially no defects and improved crystal quality can be manufactured. The above manufacturing method includes a step of inducing growth of a silicon carbide ingot (S40). Step S40 is a step of inducing growth of a silicon carbide ingot (31) under the decompressed pressure after the depressurization of the internal space is completed. Step S40 may be a step of maintaining the internal space at a constant temperature and a constant pressure and inducing growth of the silicon carbide ingot (31). Step S40 is performed by sublimating the silicon carbide raw material (20) after the temperature is increased to the temperature of step S30, thereby forming the silicon carbide ingot (31). Fig. 8 schematically illustrates the position of the coils at step S40. Referring to Fig. 8, after step S30, the plurality of coils (60) can be moved downwards in the reaction vessel (10). In the above step S40, the plurality of coils (60) are moved downwards in the reaction vessel (10), so that the difference between the upper temperature (T1) of the internal space and the lower temperature (T2) of the internal space can increase compared to the step S30. In the above step S40, the difference between the upper temperature (T1) of the internal space and the lower temperature (T2) of the internal space can be maintained at 50 ℃ to 200 ℃. After the ratio of carbon and silicon in the silicon carbide gas is stabilized by the above step S30, the temperature in the step S40 is adjusted to a specific temperature range different from that in the step S30, thereby increasing the deposition rate of the silicon carbide gas in the seed (30), and thus improving the growth rate of the silicon carbide ingot (31). The above step S40 may be performed for 5 to 180 hours. The above step S40 may be performed for 30 to 160 hours. The above step S40 may be performed for 50 to 150 hours. In the step S40, the upper temperature (T1) of the internal space may be 2,000°C to 2,250°C. In the step S40, the upper temperature (T1) of the internal space may be 2,050°C to 2,250°C. In the step S40, the upper temperature (T1) of the internal space may be 2,100°C to 2,250°C. In the step S40, the upper temperature (T1) of the internal space may be 2,100°C to 2,220°C. In the step S40, the lower temperature (T2) of the internal space may be 2,250°C to 2,350°C. In the step S40, the lower temperature (T2) of the internal space may be 2,270°C to 2,350°C. In the step S40, the lower temperature (T2) of the internal space may be 2,280°C to 2,350°C. In the step S40, the lower temperature (T2) of the internal space may be 2,280°C to 2,320°C. In the above step S40, the center position of the coil according to the above formula 1 can satisfy 20% to 50%, 22% to 50%, or 22% to 48%. When the above range is satisfied, the deposition rate of the silicon carbide gas in the seed (30) increases, so that the growth rate of the silicon carbide ingot (31) can be improved. The above manufacturing method includes a cooling step (S50). Fig. 4 is a flowchart specifically illustrating step S50. Referring to FIG. 4, the S50 step may include a step of first cooling while pressurizing the internal space (S51), a step of second cooling the temperature of the internal space to room temperature (S52), and a step of recovering the silicon carbide ingot (S53). The above step S51 may be performed while pressurizing the internal space of the reaction vessel (10) to a maximum pressure of 800 torr. The step S51 may be performed while pressurizing the internal space of the reaction vessel (10) to a pressure higher than atmospheric pressure. The step S51 may be performed at a cooling rate of 1 to 10 °C / min. The step S51 may be performed at a cooling rate of 3 to 9 °C / min. The step S51 may be performed at a cooling rate of 5 to 8 °C / min. The above step S51 can add a predetermined flow rate of an inert gas to the inside of the reaction vessel (10). The inert gas can flow in the internal space of the reaction vessel (10), and the flow can be formed in the direction of the silicon carbide raw material (20) toward the seed (30). The above step S52 may be a step of cooling the temperature of the internal space of the reaction vessel (10) to room temperature. The recovery of the silicon carbide ingot (31) in the above step S53 may be performed by cutting the rear surface of the silicon carbide ingot (31) in contact with the seed crystal (30). The above silicon carbide ingot (31) may contain 4H SiC. The surface of the above silicon carbide ingot (31) may have a convex shape or a flat shape. If the surface of the above silicon carbide ingot (31) is formed in a concave shape, other polymorphs such as 6H-SiC may be mixed in addition to the intended 4H-SiC crystal, which may lower the quality of the silicon carbide ingot (31). If the surface of the above silicon carbide ingot (31) is formed in an excessively convex shape, cracks may occur in the silicon carbide ingot (31) itself, or the crystals may break when processed into wafers. Whether the above silicon carbide ingot (31) is an excessively convex ingot is determined based on the degree of warpage, and the warpage of the silicon carbide ingot (31) manufactured according to the manufacturing method of the present invention may be 20 mm or less. The above warpage can be evaluated by placing a sample of the silicon carbide ingot (31) on which growth is completed on a platen and measuring the height of the center and edge of the ingot with respect to the rear surface of the ingot using a height gauge (Height Gauge) as a value of (center height - edge height). A positive value of the warpage value indicates convexity, a value of 0 indicates flatness, and a negative value indicates concaveness. The above silicon carbide ingot (31) may have a convex or flat surface and may have a warpage of 0 mm to 14 mm. The above silicon carbide ingot (31) may have a warpage of 0 mm to 11 mm. The above silicon carbide ingot (31) may have a warpage of 0 mm to 8 mm. When the above range is satisfied, wafer processing may be easier and the occurrence of breakage may be reduced. The above silicon carbide ingot (31) may be a substantially single-crystal 4H SiC ingot with minimal defects or polymorphic inclusions. The above silicon carbide ingot (31) is substantially composed of 4H SiC, and its surface may be convex or flat. The above silicon carbide ingot (31) can provide a silicon carbide wafer of higher quality by reducing defects that may occur in the silicon carbide ingot. The silicon carbide ingot (31) manufactured according to the manufacturing method of the present invention can reduce pits on its surface, and for example, in an ingot having a diameter of 4 inches or more, the pits included in its surface can be 10 k / cm2 or less. The surface pit measurement of the above silicon carbide ingot (31) can be evaluated by observing a total of five locations, one location in the central portion of the ingot surface excluding the facets, and four locations in the 3 o'clock, 6 o'clock, 9 o'clock, and 12 o'clock directions located approximately 10 mm inside the central portion from the ingot edge, using an optical microscope, and measuring the pit per unit area (1 ㎠) at each location, and then taking the average value. The above silicon carbide ingot (31) may have a wafer whose locking angle is obtained by applying an off-angle of 0 degrees to the (0001) plane from the above ingot, and may be -1.0 to +1.0 degrees, -0.5 to +0.5 degrees, or -0.1 to +0.1 degrees relative to the reference angle. When the above range is satisfied, the silicon carbide ingot (31) may have excellent crystal properties. The above rocking angle is measured by applying a high-resolution X-ray diffraction analysis system (HR-XRD system) to align the wafer [11-20] direction to the X-ray path, setting the X-ray source optic and X-ray detector optic angles to 2θ (35 to 36 degrees), and then adjusting the omega (ω) or theta (θ) angle to match the off-angle of the wafer to measure the rocking curve, and setting the difference between the peak angle, which is the reference angle, and the two FWHM values ​​as the rocking angle, respectively, so that the crystallinity can be evaluated. The silicon carbide ingot (31) can be processed by applying an external grinding device to trim the outer edge of the ingot (External Grinding), cutting it to a certain thickness (Slicing), and then edge grinding, surface grinding, and polishing. The above cutting step may be a step of slicing the silicon carbide ingot (31) to have a certain off-angle to prepare a sliced ​​crystal. The off-angle is in 4H SiC.

[0001] Based on the surface. The off-angle may be an angle selected from 0 to 15 degrees. The off-angle may be an angle selected from 0 to 12 degrees. The off-angle may be an angle selected from 0 to 8 degrees. The above cutting step can be applied without limitation to any slicing method commonly used in wafer manufacturing. For example, cutting using a diamond wire or a wire containing diamond slurry, or cutting using a blade or wheel partially coated with diamond, etc. can be applied. The thickness of the above-mentioned sliced ​​crystal can be adjusted in consideration of the thickness of the wafer to be manufactured, and can be sliced ​​to an appropriate thickness in consideration of the thickness after polishing in the polishing step described later. The above polishing step may be a step of polishing the sliced ​​crystal to a thickness of 300 um to 800 um to form a silicon carbide wafer. The above polishing step may be performed using a polishing method typically applied to wafer manufacturing. For example, a method in which polishing is performed after processes such as lapping and / or grinding is performed may be applied. Hereinafter, the present invention will be described in more detail based on examples and comparative examples. However, the following examples and comparative examples are merely illustrative examples for further explaining the present invention, and the present invention is not limited to the following examples and comparative examples. Example Example 1 <Manufacturing of silicon carbide ingots> As in the silicon carbide ingot manufacturing device illustrated in FIG. 5, silicon carbide raw material (20) was charged into the inner space of a reaction vessel (10) having a height of 220 mm, and a seed crystal (30) was placed on the upper portion of the inner space. The seed crystal (30) was made of a 6-inch 4H-SiC crystal, and was fixed so that the C plane ((0001) plane) faced the silicon carbide raw material (20). Thereafter, the crucible body (11) was covered using a crucible cover (12), the outside was surrounded with an insulating material (40), and a coil (60), which is a heating means, was placed on the outside. As illustrated in FIG. 6, the coil (60) was placed such that the distance (d2) from the reaction vessel was about 60 mm, the diameter (r) was about 20 mm, and the spacing (d1) between the coils was about 25 mm. Additionally, the induced current of the coil (60) is about 1.5 × 10 5 It was set to A. The internal space of the above reaction vessel (10) was depressurized to adjust to a vacuum atmosphere, and argon (Ar) gas was injected so that the internal space reached 760 torr. Thereafter, the temperature was initially increased at a rate of 10 ℃ / min to approximately 1600 ℃ based on the lower temperature (T2) of the internal space. Thereafter, the internal space was depressurized and the temperature was increased for a second time at a rate of 4 ℃ / min to 5 ℃ / min, and at this time, the center position of the coil (60), the upper temperature (T1) of the internal space, the lower temperature (T2) of the internal space, and the difference between the upper temperature (T1) and the lower temperature (T2) of the internal space were set to the conditions shown in Table 1 below. After the depressurization of the internal space was completed, the central position of the coil (60) was changed to grow a silicon carbide ingot (31) on the surface of the seed (30) for about 100 hours. At this time, the central position of the coil (60), the upper temperature (T1) of the internal space, the lower temperature (T2) of the internal space, and the difference between the upper temperature (T1) and the lower temperature (T2) of the internal space were set to the conditions shown in Table 1 below. Afterwards, the temperature of the internal space was cooled to 25 ℃ at a rate of 5 ℃ / min, and at the same time, argon (Ar) gas was injected so that the pressure of the internal space became 760 torr, and the silicon carbide ingot formed in the seed hole (30) was recovered. <Manufacturing of wafer samples> The outer surface of the silicon carbide ingot was ground to about 5% of the maximum outer diameter to process it into a cylindrical shape with a uniform outer diameter, and cut to have an off angle of about 4° with respect to the (0001) plane of the silicon carbide ingot, to manufacture a wafer sample with a thickness of 360 μm. Examples 2 to 6 and Comparative Examples 1 to 4 Silicon carbide ingot and wafer samples were manufactured by the same process as Example 1, except that the silicon carbide ingot was manufactured under the conditions shown in Table 1 below. Second heating stage: Growth induction stage of silicon carbide ingot: Coil center position 1) Temperature of the upper part of the internal space 2) Internal space lower temperature 3) temperature difference 4) Coil center position 1) Internal space upper temperature 2) Internal space lower temperature 3) temperature difference 4) Unit %℃%℃Example 154.52,2252,3007545.52,2102,30090Example 256.82,2502,3005047.72,2202,30080Example 352.32,2302,3007041.02,2002,300100Example 447.72,2202,3008022.72,1502,300150Example 547.72,2202,3008022.72,1502,300150Example 641.02,2002,30010031.82,1002,300200Comparative Example 11002,2702,300301002,2702,30030Comparative example 231.82,1002,30020031.82,1002,300200Comparative example 377.32,2602,3004022.72,1502,300150Comparative example 49.12,0002,3003004.51,9002,3004001) Coil center position: (H1(mm) / 220(mm) in Fig. 7) × 1002) Internal space upper temperature: Temperature measured at T1 in Fig. 53) Internal space lower temperature: Temperature measured at T2 in Fig. 54) Temperature difference: Temperature measured at T2 in Fig. 5 - Temperature measured at T1 Experimental example Experimental Example 1 - Defect Evaluation The surfaces of the silicon carbide ingots manufactured in Example 1 and Comparative Examples 1 and 2 were photographed using an optical microscope (Eclipse LV150, Nikon). The photograph of Example 1 is shown in Fig. 9, the photograph of Comparative Example 1 is shown in Fig. 10, and the photograph of Comparative Example 2 is shown in Fig. 11. Separately, each of the wafer samples manufactured in Examples 1 to 6 and Comparative Examples 1 to 4 was cut into a size of 50 mm Х 50 mm, and then etched by immersing in potassium hydroxide (95%) at a temperature of 600 ° C. for 3 minutes. Thereafter, the surface of the etched wafer sample was photographed using the optical microscope (Eclipse LV150, Nikon). The photograph of Example 1 is shown in FIG. 12, the photograph of Comparative Example 1 is shown in FIG. 13, and the photograph of Comparative Example 2 is shown in FIG. 14. In addition, in order to quantitatively evaluate the defect density of the wafer sample, an area of ​​500 Х 500 ㎛ on the surface of the wafer sample was arbitrarily designated 12 times, and the number of defects in each area was determined, and the average number of defects per unit area was calculated, and the results are shown in Table 2 below. Experimental Example 2 - Growth Rate Evaluation The growth rates of the silicon carbide ingots of each of Examples 1 to 6 and Comparative Examples 1 to 4 were measured, and the results are shown in Table 2 below. Experimental Example 3 - Seed loss evaluation The presence or absence of seed loss in the silicon carbide ingot manufacturing process of Examples 1 to 6 and Comparative Examples 1 to 4 was evaluated according to the following criteria, and the results are shown in Table 2 below. - Good: No cracks observed - Defect: Cracks observed due to seed loss Classification EPD 1) Growth rate, seed quality loss, evaluation unit, number of defects / cm 2㎛ / h-Example 18,560240Good Example 28,230240Good Example 38,540240Good Example 48,630245Good Example 58,620245Good Example 68,960250Good Comparative Example 135,880175Poor Comparative Example 225,660250Poor Comparative Example 329,810180Poor Comparative Example 455,340265Poor1) EPD: Etch Pit Density Looking at Tables 1 and 2 above, in the step of increasing the temperature of the internal space by a heating means while depressurizing the internal space, it was confirmed that in Examples 1 to 6, in which the difference between the upper temperature of the internal space and the lower temperature of the internal space was set to 50°C to 100°C, defects were significantly reduced and seed crystals were not lost compared to Comparative Examples 1 to 4. More specifically, looking at the surface photograph of the silicon carbide ingot of Example 1 (Fig. 9), it was confirmed that defects were significantly reduced compared to the surface photograph of the silicon carbide ingot of Comparative Example 1 (Fig. 10) and the surface photograph of the silicon carbide ingot of Comparative Example 2 (Fig. 11). In addition, in the step of inducing growth of the silicon carbide ingot, in Examples 1 to 6, in which the difference between the upper temperature of the internal space and the lower temperature of the internal space was set to 50°C to 200°C by changing the center position of the coil, it was confirmed that the deposition rate of silicon carbide gas in the seed crystal increased compared to Comparative Examples 1 and 3, and thus the growth rate of the silicon carbide ingot was improved. The embodiment can be applied to a method for manufacturing a silicon carbide ingot.

Claims

1. A step of placing silicon carbide raw material and seed crystals in a reaction vessel having an internal space; A step of first increasing the temperature of the internal space by a heating means surrounding the reaction vessel; A step of secondarily increasing the temperature of the internal space by the heating means while depressurizing the internal space; A step of inducing growth of a silicon carbide ingot under the decompressed pressure by completing depressurization of the internal space; and It includes a step of cooling the temperature of the internal space to room temperature, The above internal space includes an upper portion where the seed is arranged and a lower portion where the silicon carbide raw material is arranged. A method for manufacturing a silicon carbide ingot, wherein, in the second heating step, the difference between the upper temperature of the internal space and the lower temperature of the internal space is maintained at 50°C to 100°C.

2. In paragraph 1, A method for manufacturing a silicon carbide ingot, wherein the first heating step is performed until the depressurization of the internal space begins.

3. In paragraph 1, A method for manufacturing a silicon carbide ingot, wherein the above-mentioned second heating step is performed until the depressurization of the internal space is completed.

4. In paragraph 1, A method for manufacturing a silicon carbide ingot, wherein in the second heating step, the upper temperature of the internal space is 2,200 ℃ to 2,250 ℃.

5. In paragraph 1, A method for manufacturing a silicon carbide ingot, wherein in the second heating step, the lower temperature of the internal space is 2,250 ℃ to 2,350 ℃.

6. In paragraph 1, A method for manufacturing a silicon carbide ingot, wherein, in the step of inducing growth of the silicon carbide ingot, the difference between the upper temperature of the internal space and the lower temperature of the internal space is maintained at 50°C to 200°C.

7. In paragraph 1, A method for manufacturing a silicon carbide ingot, wherein, in the first heating step, the difference between the upper temperature of the internal space and the lower temperature of the internal space is maintained at 40°C to 60°C.

8. In paragraph 1, A method for manufacturing a silicon carbide ingot, wherein the heating means includes a plurality of coils that move in the height direction of the reaction vessel and generate an induced current in the reaction vessel.

9. In paragraph 8, A method for manufacturing a silicon carbide ingot, wherein the distance between the coil and the reaction vessel is 60 mm to 600 mm.

10. In paragraph 8, A method for manufacturing a silicon carbide ingot, wherein each of the plurality of coils has a diameter of 5 mm to 40 mm and the spacing between the plurality of coils is 5 mm to 30 mm.

11. In paragraph 8, The induced current in the above coil is 1 × 10 4 A to 2 × 10 6 A method for manufacturing a silicon carbide ingot, which is A.

12. In paragraph 8, A method for manufacturing a silicon carbide ingot, wherein in the second heating step, the center position of the coil according to the following formula 1 satisfies 40% to 60%: [Formula 1] Coil center position (%) = (H1 / H0) × 100 In the above equation 1, H0 is the total height of the reaction vessel, and H1 is the height of the reaction vessel at a position corresponding to the center of the plurality of coils based on the height direction of the reaction vessel.

13. In paragraph 12, A method for manufacturing a silicon carbide ingot, wherein the center position of the coil according to the above formula 1 satisfies 53% to 57%.

14. In paragraph 12, A method for manufacturing a silicon carbide ingot, wherein, in the step of inducing growth of the silicon carbide ingot, the center position of the coil according to the above formula 1 satisfies 20% to 50%.

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