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: 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 method for preparing a seed crystal including a protective film includes preparing i) a first layer composition of a first binder resin and a first solvent and ii) a second layer composition of a second binder resin, a filler, and a second solvent, applying the first layer composition to the rear surface of a seed crystal to form a first coating layer on the rear surface of the seed crystal and drying the first coating layer to form a first layer on the rear surface of the seed crystal, and applying the second layer composition onto the first layer to form a second coating layer on the first layer, followed by heat treating to form a second layer on the first layer wherein the first layer and the second layer are sequentially disposed on the rear surface of the seed crystal, and wherein the first layer has a thickness corresponding to 30% or less of the distance from the bottom surface of the first layer to the top surface of the second layer.

Abstract: A silicon carbide ingot manufacturing method and a silicon carbide ingot manufacturing system are provided. The silicon carbide ingot manufacturing method and the silicon carbide ingot manufacturing system may change a temperature gradient depending on the growth of an ingot by implementing a guide which has a tilted angle to an external direction from the interior of a reactor, in an operation to grow an ingot during a silicon carbide ingot manufacturing process.

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: A method for producing an ingot includes loading a raw material comprising a raw material powder having a D50 of 80 ?m or more into a reactor (loading step), controlling the internal temperature of the reactor such that adjacent particles of the raw material powder are interconnected to form a necked raw material (necking step), and sublimating components of the raw material from the necked raw material to grow an ingot (ingot growth step).

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 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 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 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 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 epitaxial wafer including a wafer having one surface and an other surface, and an epitaxial layer formed on the one surface of the wafer, wherein a roughness skewness (Rsk) of the one surface is ?3 nm to 3 nm, and a roughness average (Ra) of an edge area of the one surface is different from that of a central area of the one surface by ?2 nm to 2 nm when the edge area of the one surface is defined as an area between 13.3% and 32.1% of the radius of the wafer in a direction from the edge of the one surface toward the center thereof and the central area of the one surface is defined as an area at 9.4% of the radius of the wafer from the center of the one surface.

Abstract: An apparatus for producing an ingot includes a crucible body having an opening and in which raw materials are accommodated, and a lid assembly located at the opening and having a portion fixed to the crucible body. The lid assembly includes a placement hole having open upper and lower ends, a frame member arranged along a periphery of the opening while surrounding a periphery of the placement hole, and a core member located in the placement hole and movable upward and downward with respect to the frame member.

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: 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 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 method for preparing a SiC ingot includes preparing a crucible assembly comprising a crucible body having an internal space, loading a raw material into the internal space of the crucible body and placing a plurality of SiC seed in the internal space of the crucible body at regular intervals spaced apart from the raw material, and growing the SiC ingot from the plurality of SiC seed by adjusting the internal space of the crucible body to a crystal growth atmosphere such that the raw material is vapor-transported and deposited to the plurality of SiC seed. A density of the crucible body may be 1.70 to 1.92 g/cm3.

Abstract: An adhesive layer of seed crystal includes a graphitized adhesive layer, wherein the graphitized adhesive layer is prepared by heat-treating a pre-carbonized adhesive layer, and wherein the adhesive layer has Vr value of 28%/mm3 or more, and the Vr value is represented by Equation 1 below: Vr ? = { Sq ( V ? 1 - V ? 2 ) } × 1 ? 0 3 [ Equation ? ? 1 ] where Sg (%) is represented by Equation 2 below, V1 is a volume (mm3) of the pre-carbonized adhesive layer, and V2 is a volume (mm3) of the graphitized adhesive layer, Sg ? = { 1 - ( A ? 2 A ? 1 ) } × 1 ? 0 ? 0 ? % [ Equation ? ? 2 ] where A1 is an area (mm2) of the pre-carbonized adhesive layer, and A2 is an area (mm2) of the graphitized adhesive layer.

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: Disclosed is a method of providing a sign language video reflecting an appearance of a conversation partner. The method includes recognizing a speech language sentence from speech information, and recognizing an appearance image and a background image from video information. The method further comprises acquiring multiple pieces of word-joint information corresponding to the speech language sentence from joint information database, sequentially inputting the word-joint information to a deep learning neural network to generate sentence-joint information, generating a motion model on the basis of the sentence-joint information, and generating a sign language video in which the background image and the appearance image are synthesized with the motion model. The method provides a natural communication environment between a sign language user and a speech language user.