In various embodiments, controlled heating and/or cooling conditions are utilized during the fabrication of aluminum nitride single crystals and aluminum nitride bulk polycrystalline ceramics. Thermal treatments may also be utilized to control properties of aluminum nitride crystals after fabrication.

A member for an apparatus for manufacturing a semiconductor single crystal having long product life and a tantalum carbide coated carbon material are provided. The tantalum carbide coated carbon material according to the present invention is a tantalum carbide coated carbon material in which at least a part of a surface of a carbon base material is coated with a tantalum carbide coated film containing tantalum carbide as a main component, in which in the tantalum carbide coated film, an intensity of an X-ray diffraction line corresponding to a plane with respect to an out-of-plane direction is larger than intensities of X-ray diffraction lines corresponding to other crystal planes, and the intensity ratio is 60% or more with respect to a sum of intensities of X-ray diffraction lines corresponding to all crystal planes.

A member for an apparatus for manufacturing a semiconductor single crystal having long product life and a tantalum carbide coated carbon material are provided. The tantalum carbide coated carbon material according to the present invention is a tantalum carbide coated carbon material in which at least a part of a surface of a carbon base material is coated with a tantalum carbide coated film containing tantalum carbide as a main component, in which in the tantalum carbide coated film, an intensity of an X-ray diffraction line corresponding to a plane with respect to an out-of-plane direction is larger than intensities of X-ray diffraction lines corresponding to other crystal planes, and the intensity ratio is 60% or more with respect to a sum of intensities of X-ray diffraction lines corresponding to all crystal planes.

A silicon carbide crystal includes a seed layer, a bulk layer, and a stress buffering structure formed between the seed layer and the bulk layer. The seed layer, the bulk layer, and the stress buffering structure are each formed with a dopant that cycles between high and low dopant concentration. The stress buffering structure includes a plurality of stacked buffer layers and a transition layer over the buffer layers. The buffer layer closest to the seed layer has the same variation trend of the dopant concentration as the buffer layer closest to the transition layer, and the dopant concentration of the transition layer is equal to the dopant concentration of the seed layer.

A composite substrate includes: a piezoelectric layer; and a reflective layer arranged on a rear surface side of the piezoelectric layer, wherein the reflective layer includes a high-impedance layer and a low-impedance layer containing silicon oxide, and wherein a ratio of a region of first structures in the high-impedance layer is more than 70%.

A system for simultaneously manufacturing more than one single crystal of a semiconductor material by physical vapor transport (PVT) includes a plurality of reactors and a common vacuum channel connecting at least a pair of reactors of the plurality of reactors. Each reactor has an inner chamber adapted to accommodate a PVT growth structure for growth of a single semiconductor crystal. The common vacuum channel is connectable to a vacuum pump system for creating and/or controlling a common gas phase condition in the inner chambers of the pair of reactors.

A gas phase nanowire growth apparatus including a reaction chamber, a first input and a second input. The first input is located concentrically within the second input and the first and second input are configured such that a second fluid delivered from the second input provides a sheath between a first fluid delivered from the first input and a wall of the reaction chamber.

This disclosure relates to methods of growing crystalline layers on amorphous substrates by way of an ultra-thin seed layer, methods for preparing the seed layer, and compositions comprising both. In an aspect of the invention, the crystalline layers can be thin films. In a preferred embodiment, these thin films can be free-standing.

A method for producing a p-type 4H—SiC single crystal includes sublimating a nitrided aluminum raw material and a SiC raw material. Further, there is a stacking of a SiC single crystal, which is co-doped with aluminum and nitrogen, on one surface of a seed crystal.

[Object] To provide a thin plate-shaped single-crystal production equipment and a thin plate-shaped single-crystal production method that can produce a thin plate-shaped single crystal having a uniform dopant concentration at an optimum chemical composition and a thickness of several hundreds of micrometers continuously at low cost with high precision even when the single crystal is a single crystal of an incongruent melting material or a solid solution material or a single crystal of a congruent melting material.

[Solution] Thin plate-shaped single-crystal production equipment includes: an infrared ray irradiation apparatus that irradiates an upper surface of a raw material lump for production of a thin plate-shaped single crystal with an infrared ray to melt the upper surface; and an elevator apparatus that causes a lower surface of a thin plate-shaped seed single crystal to be immersed in a melt melted using the infrared ray irradiation apparatus and formed on the upper surface and then pulls the thin plate-shaped seed single crystal immersed in the melt upward. The thin plate-shaped single-crystal production equipment is configured such that, by using the elevator apparatus to immerse the lower surface of the thin plate-shaped seed single crystal in the melt formed on the upper surface of the raw material lump for the production of the thin plate-shaped single crystal using the infrared ray irradiation apparatus, growth of a single crystal is started from the lower surface of the immersed thin plate-shaped seed single crystal and that, by using the elevator apparatus to pull the thin plate-shaped seed single crystal upward, the thin plate-shaped single crystal is produced continuously.