Abstract: The wafer having a retardation distribution measured with a light having a wavelength of 520 nm, wherein an average value of the retardation is 38 nm or less, wherein the wafer comprises a micropipe, and wherein a density of the micropipe is 1.5/cm2 or less, is disclosed.

Abstract: Example embodiments relate to a method of measurement, an apparatus for measurement, and an ingot growing system that measure properties relating an induction heating characteristic of a graphite article. The method of measurement comprises an arranging step of arranging a graphite article to the coil comprising a winded conducting wire; and a measuring step of applying power for measurement to the coil through means of measurement connected electronically to the coil, and measuring electromagnetic properties induced in the coil. The method of measurement and the like measure electromagnetic properties of graphite articles like an ingot growing container, and an insulating material, and provide data required for selecting so that further enhanced reproducibility for growth of an ingot can be secured.

Abstract: A method of growing a semi-insulating SiC single crystal ingot, the method comprising the steps of: (1) placing a dopant coated with silicon carbide (SiC) and a carbon-based material into a reaction vessel containing a seed crystal fixed thereto; and (2) growing a SiC single crystal on the seed crystal, thereby yielding a high-quality semi-insulating SiC single crystal ingot with a uniform thickness-based doping concentration. In addition, another embodiment relates to a method of growing a semi-insulating silicon carbide single crystal ingot, the method comprising the steps of: (a) placing in a reaction vessel, a composition comprising a carbon-containing polymer resin, a solvent, a dopant, and silicon carbide (SiC); (b) solidifying the composition; and (c) growing a SiC single crystal ingot on a seed crystal fixed to the reaction vessel, thereby yielding a high-quality semi-insulating SiC single crystal ingot with a uniform thickness-based doping concentration.

Abstract: An intake-type smoke removal system is disclosed. The intake-type smoke removal system discharges gas flowing into a smoke removal zone to the outside of the smoke removal zone and includes a vacuum generating multistage Venturi configured to allow water provided from the outside to pass therethrough, the vacuum generating multistage Venturi being configured to generate negative pressure based on the Venturi effect while the water passes therethrough to suck the gas in the smoke removal zone, mix the sucked gas with the water, and discharge the gas mixed with the water.

Abstract: A method of manufacturing a silicon carbide ingot, includes a preparing operation of adjusting internal space of a reactor in which silicon carbide raw materials and a seed crystal are disposed to have a high vacuum atmosphere, a proceeding operation of injecting an inert gas into the internal space, heating the internal space by moving a heater surrounding the reactor to induce the silicon carbide raw materials to sublimate, and growing the silicon carbide ingot on the seed crystal, and a cooling operation of cooling the temperature of the internal space to room temperature. The moving of the heater has a relative position which becomes more distant at a rate of 0.1 mm/hr to 0.48 mm/hr based on the seed crystal.

Abstract: A multifunctional sprinkler device concealed in a ceiling for simultaneously removing smoke and toxic gas is disclosed. The multifunctional sprinkler device concealed in a ceiling for simultaneously removing smoke and toxic gas, in the event of a fire, suctions and removes surrounding smoke and toxic gas while spraying water and at the same time, prevents suffocation by lowering a lethal dose of the toxic gas to be lower than or equal to a safe range within a short time, and provides lighting even in the event of a fire and power outage to guide rapid evacuation.

Abstract: An embodiment relates to a multilayer graphite sheet with excellent electromagnetic shielding capability and thermal conductivity, and a manufacturing method therefor, wherein the multilayer graphite sheet has a multilayer structure of five or more layers in total and can be manufactured to have a thick thickness of 70 ?m or more such that the electromagnetic shielding capability can be significantly improved. In addition, the multilayer graphite sheet is manufactured by graphitizing a hybrid laminate in which heterogeneous materials are mixed such that thermal conductivity and electromagnetic shielding capability can be simultaneously realized at a lower cost, thereby being useful as a thick film sheet which used in various applications such as home appliances and electric vehicles.

Abstract: A method for preparing a SiC ingot includes: preparing a reactor by disposing a raw material in a crucible body and disposing a SiC seed in a crucible cover, and then wrapping the crucible body with a heat insulating material having a density of 0.14 to 0.28 g/cc; and growing the SiC ingot from the SiC seed by placing the reactor in a reaction chamber and adjusting an inside of the reactor to a crystal growth atmosphere such that the raw material is vapor-transported and deposited to the SiC seed.

Abstract: Disclosed are a silicon carbide powder, a method of manufacturing a silicon carbide powder, and a silicon carbide wafer. More particularly, the silicon carbide powder includes carbon and silicon and in the silicon carbide powder, O1s/C1s of a surface measured by X-ray photoelectron spectroscopy is 0.28 or less.

Abstract: Disclosed are a silicon carbide powder and a method of manufacturing a silicon carbide ingot using the same. More particularly, the silicon carbide powder includes carbon and silicon and has a particle circularity of 0.4 to 0.9 measured through 2D image analysis.

Abstract: A method of growing a semi-insulating SiC single crystal ingot, the method comprising the steps of: (1) placing a dopant coated with silicon carbide (SiC) and a carbon-based material into a reaction vessel containing a seed crystal fixed thereto; and (2) growing a SiC single crystal on the seed crystal, thereby yielding a high-quality semi-insulating SiC single crystal ingot with a uniform thickness-based doping concentration. In addition, another embodiment relates to a method of growing a semi-insulating silicon carbide single crystal ingot, the method comprising the steps of: (a) placing in a reaction vessel, a composition comprising a carbon-containing polymer resin, a solvent, a dopant, and silicon carbide (SiC); (b) solidifying the composition; and (c) growing a SiC single crystal ingot on a seed crystal fixed to the reaction vessel, thereby yielding a high-quality semi-insulating SiC single crystal ingot with a uniform thickness-based doping concentration.

Abstract: Disclosed are a silicon carbide wafer and a method of manufacturing the same. The silicon carbide wafer includes an upper surface and a lower surface, the upper surface includes a first target region, the first target region being within 85% of a radius of the upper surface based on a center of the upper surface, a first peak omega angle measured at intervals of 15 mm in a first direction in the first target region is within ?1° to +1° based on a peak omega angle measured at the center of the upper surface, and the first direction is a [1-100] direction and a direction passing through the center of the upper surface.

Abstract: A method of cleaning a wafer comprises: a scrubbing operation comprising treating a target wafer to be cleaned with a brush at a rotation rate of 200 rpm or less to prepare a brush cleaned wafer; and a cleaning operation comprising cleaning the brush cleaned wafer with a cleaning solution to prepare a cleaned bare wafer, wherein the cleaning operation comprises a first cleaning operation and a second cleaning operation sequentially.

Abstract: A silicon carbide ingot producing method is provided. The method produces a silicon carbide ingot in which an internal space of a reactor is depressurized and heated to create a predetermined difference in temperature between upper and lower portions of the internal space. The method produces a silicon carbide ingot in which a plane of a seed crystal corresponding to the rear surface of the silicon carbide ingot is lost minimally. Additionally, the method produces a silicon carbide ingot with few defects and good crystal quality.

Abstract: A wafer having relaxation moduli different by 450 GPa or less, as determined by dynamic mechanical analysis, when loaded to 1 N and 18 N with a loading rate of 0.1 N/min at a temperature of 25° C.

Abstract: A graphite sheet having a ratio of thermal diffusivity in horizontal and vertical directions of 300 or more is disclosed. Also, a graphite sheet having a ratio of thermal diffusivity in a vertical direction of 2.0 mm2/s or less is disclosed. The graphite sheet has excellent thermal conductivity in horizontal and vertical directions and excellent flexibility at the same time and can be produced at low manufacturing cost, thereby holding an economic advantage.

Abstract: A silicon carbide wafer has one surface and the other surface opposite to the one surface. An average Rmax roughness of the one surface is 2.0 nm or less, and an average Ra roughness of the one surface is 0.1 nm or less. An edge region is a region in which a distance from an edge of the silicon carbide wafer toward a center is 5% to 75% of a radius of the silicon carbide wafer, and a central region is a region having a radius of 25% of the radius of the silicon carbide wafer at the center of the silicon carbide wafer. A difference between an average Rmax roughness of the edge region of the one surface and an average Rmax roughness of the central region of the one surface is 0.01 nm to 0.5 nm.

Abstract: A SiC ingot includes: a main body including a first cross-sectional plane of the main body and a second cross-sectional plane of the main body facing the first cross-sectional plane; and a protrusion disposed on the second cross-sectional plane and including a convex surface from the second cross-sectional plane of the main body, wherein a first end point disposed at one end of the second cross sectional plane, a second end point disposed at another end of the second cross sectional plane, and a peak point disposed on the convex surface are disposed on a third cross-sectional plane of the main body perpendicular to the first cross-sectional plane, and wherein a radius of curvature of an arc corresponding to a line of intersection between the third cross-sectional plane and the convex surface satisfies Equation 1 below: 3D?r?37D??[Equation 1] where r is the radius of curvature of the arc corresponding to the line of intersection between the third cross-sectional plane and the convex surface, and D is a leng

Abstract: A method for preparing a SiC ingot includes: disposing a raw material and a SiC seed crystal facing each other in a reactor having an internal space; subliming the raw material by controlling a temperature, a pressure, and an atmosphere of the internal space; growing the SiC ingot on the seed crystal; and collecting the SiC ingot after cooling the reactor. The wafer prepared from the ingot, which is prepared from the method, generates cracks when an impact is applied to a surface of the wafer, the impact is applied by an external impact source having mechanical energy, and a minimum value of the mechanical energy is 0.194 J to 0.475 J per unit area (cm2).

Abstract: A SiC ingot includes: a main body including a first cross-sectional plane of the main body and a second cross-sectional plane of the main body facing the first cross-sectional plane; and a protrusion disposed on the second cross-sectional plane and including a convex surface from the second cross-sectional plane of the main body, wherein a first end point disposed at one end of the second cross sectional plane, a second end point disposed at another end of the second cross sectional plane, and a peak point disposed on the convex surface are disposed on a third cross-sectional plane of the main body perpendicular to the first cross-sectional plane, and wherein a radius of curvature of an arc corresponding to a line of intersection between the third cross-sectional plane and the convex surface satisfies Equation 1 below: 3D?r?37D??[Equation 1] where r is the radius of curvature of the arc corresponding to the line of intersection between the third cross-sectional plane and the convex surface, and D is a lengt