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: Disclosed is a method of manufacturing a silicon carbide wafer. The method of manufacturing a silicon carbide wafer includes a step of disposing a silicon carbide block in a crucible; a step of sublimating a silicon carbide included in the silicon carbide block to form a silicon carbide ingot; and a step of processing the silicon carbide ingot.

Abstract: In a silicon carbide wafer in an embodiment, in the photoluminescence signal intensity spectrum obtained after irradiating a laser on one surface of the silicon carbide wafer, the number of peak signals having an intensity more than 1.2 times the average signal intensity of the spectrum is 1/cm2 or less.

Abstract: A thrust enhancing device is disclosed. The thrust enhancing device enhances thrust of a thrust generation part in a state coupled to the thrust generation part configured to obtain a propulsive force by using a reaction force of a fluid. The thrust enhancing device includes a venturi part configured to receive a basic fluid allowed to flow by the thrust generation part and allow the basic fluid to pass through the inside thereof, and an ejection induction part disposed in an inner flow field of the venturi part and configured to linearize a flow of a fluid to be ejected to the outside of the venturi part.

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 silicon carbide wafer manufacturing method includes: a bending measuring step of measuring a first edge having the greatest degree of a bending at one surface of a silicon carbide ingot having one surface; a cutting start step of starting a cutting at a second edge having a distance of r×a along an edge of the one surface from the first edge in a direction parallel to or with a predetermined off angle with respect to the one surface through the wire saw, a cutting speed being decreased to a first cutting speed in the cutting start step; a cutting proceeding step in which the first cutting speed is substantially constant within a variation of about ±5% of the first cutting speed; and a finish step in which the cutting speed is increased from the first cutting speed and the cutting of the silicon carbide ingot is completed.

Abstract: A wafer manufacturing method, an epitaxial wafer manufacturing method, and a wafer and epitaxial wafer manufactured thereby, are provided. The wafer manufacturing method enables the manufacture of a wafer with a low density of micropipe defects and minimum numbers of particles and scratches. The epitaxial wafer manufacturing method enables the manufacture of an epitaxial wafer that has low densities of defects such as downfall, triangular, and carrot defects, exhibits excellent device characteristics, and improves the yield of devices.

Abstract: A thrust enhancing device is disclosed. The thrust enhancing device enhances thrust of a thrust generation part in a state coupled to the thrust generation part configured to obtain a propulsive force by using a reaction force of a fluid. The thrust enhancing device includes a venturi part configured to receive a basic fluid allowed to flow by the thrust generation part and allow the basic fluid to pass through the inside thereof, and an ejection induction part disposed in an inner flow field of the venturi part and configured to linearize a flow of a fluid to be ejected to the outside of the venturi part.

Abstract: A wafer manufacturing method, an epitaxial wafer manufacturing method, and a wafer and epitaxial wafer manufactured thereby, are provided. The wafer manufacturing method enables the manufacture of a wafer with a low density of micropipe defects and minimum numbers of particles and scratches. The epitaxial wafer manufacturing method enables the manufacture of an epitaxial wafer that has low densities of defects such as downfall, triangular, and carrot defects, exhibits excellent device characteristics, and improves the yield of devices.

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: 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.