An apparatus for the manufacture of synthetic diamonds includes a pressure vessel having a chamber therein, and a body located in the chamber. The pressure vessel and the body are formed of materials having different coefficients of expansion. The coefficient of expansion of the body is greater than the coefficient of expansion of the pressure vessel. The pressure vessel is formed from a material having a melting point in excess of 1327° C. and capable of withstanding a pressure of at least 4.4 Gpa at a temperature of at least 1327° C. The chamber is configured to receive the body, and a carbon source, the apparatus further comprising a heating means configured to heat at least the body to a temperature at least of 1327° C. The coefficient of expansion of the body is selected such that upon heating thereof to at least 1327° C. the pressure exerted on the carbon source is at least 4.4 Gpa.

A crucible device includes a heating chamber, at least a first crucible in which a first crystal is growable, and at least a second crucible in which a second crystal is growable. The first crucible and the second crucible are arranged within the heating chamber spaced apart from each other along a horizontal and vertical and any orientational direction. The crucible device further comprises a heating system arranged within the heating chamber, wherein the heating system is configured for adjusting a temperature along the horizontal and vertical and any orientational directions.

In a method for manufacturing a silicon carbide ingot, a silicon carbide ingot, a system for manufacturing a silicon carbide into according to embodiments of the present invention, a crucible assembly comprising a crucible body having an inner space and a crucible cover covering the crucible body, a silicon carbide ingot is grown after disposing a raw material and a silicon carbide seed, wherein a weight of the crucible assembly is set to have a weight ratio of 1.5 to 2.7 when a weight of the raw material is regarded as 1. Thus, a silicon carbide ingot has a large area and reduced defects can be manufactured.

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.

A crucible for growing a metal oxide single crystal is provided that can facilitate the balance between the thickness and the strength (hardness) of the constant diameter portion of the crucible and is capable of performing growth of a crystal having a large diameter. The crucible according to the present invention is a crucible for growing a metal oxide single crystal, including a reinforcing belt material provided on an outer periphery of a constant diameter portion of the crucible. It is possible that the crucible has an upper portion having a thickness that is smaller than a thickness of a lower portion of the crucible, and the upper portion of the crucible is the constant diameter portion.

A gallium oxide crystal manufacturing device includes a crucible to hold a gallium oxide source material therein, a crucible support that supports the crucible from below, a crucible support shaft that is connected to the crucible support from below and vertically movably supports the crucible and the crucible support, a tubular furnace core tube that surrounds the crucible, the crucible support and the crucible support shaft, a tubular furnace inner tube that surrounds the furnace core tube, and a resistive heating element including a heat-generating portion placed in a space between the furnace core tube and the furnace inner tube. Melting points of the furnace core tube and the furnace inner tube are not less than 1900° C. A thermal conductivity of a portion of the furnace core tube located directly next to the crucible in a radial direction thereof is higher than a thermal conductivity of the furnace inner tube.

A method for producing a solar crucible includes providing a crucible base body of transparent or opaque fused silica having an inner wall, providing a dispersion containing amorphous SiO.sub.2 particles, applying a SiO.sub.2-containing slip layer to at least a part of the inner wall by using the dispersion, drying the slip layer to form a SiO.sub.2-containing grain layer and thermally densifying the SiO.sub.2-containing grain layer to form a diffusion barrier layer. The dispersion contains a dispersion liquid and amorphous SiO.sub.2 particles that form a coarse fraction and a fine fraction with SiO.sub.2 nanoparticles. The weight percentage of the SiO.sub.2 nanoparticles based on the solids content of the dispersion is in the range between 2 and 15% by weight. The SiO.sub.2-containing grain layer is thermally densified into the diffusion barrier layer through the heating up of the silicon in the crystal growing process.

A method for manufacturing a silicon carbide single crystal includes: packing a silicon carbide source material into a crucible, the silicon carbide source material having a flowability index of not less than 70 and not more than 100; and sublimating the silicon carbide source material by heating the silicon carbide source material.

Provided is a method of enhancing silicon carbide monocrystalline growth yield, including the steps of: (A) filling a bottom of a graphite crucible with a silicon carbide raw material selected; (B) performing configuration modification on a graphite seed crystal platform; (C) fastening a silicon carbide seed crystal to the modified graphite seed crystal platform with a graphite clamping accessory; (D) placing the graphite crucible containing the silicon carbide raw material and the silicon carbide seed crystal in an inductive high-temperature furnace; (E) performing silicon carbide crystal growth process by physical vapor transport; and (F) obtaining silicon carbide monocrystalline crystals. The geometric configuration of the surface of the graphite seed crystal platform is modified to eradicate development of peripheral grain boundary.

A vacuum system for silicon crystal growth includes a silicon crystal growth chamber, a first vacuum pipe, a second vacuum pipe, and an oxides container. The first vacuum pipe is coupled to the chamber and has within a first brush that is movable in a first direction for removing internal oxides. The second vacuum pipe is coupled to the first vacuum pipe for receiving the internal oxides via the first brush and has within a second brush that is movable in a second direction different from the first direction. The second brush transports the received internal oxides away from the first vacuum pipe. The oxides container is coupled to the second vacuum pipe for receiving the internal oxides via the second brush.