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.

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.

A method for manufacturing an epitaxial wafer comprising a silicon carbide substrate and a silicon carbide voltage-blocking-layer, the method includes: epitaxially growing a buffer layer on the substrate, doping a main dopant for determining a conductivity type of the buffer layer and doping an auxiliary dopant for capturing minority carriers in the buffer layer at a doping concentration less than the doping concentration of the main dopant, so that the buffer layer enhances capturing and extinction of the minority carriers, the minority carriers flowing in a direction from the voltage-blocking-layer to the substrate, so that the buffer layer has a lower resistivity than the voltage-blocking-layer, and so that the buffer layer includes silicon carbide as a main component; and epitaxially growing the voltage-blocking-layer on the buffer layer.

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 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 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.

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.

An object of the present invention is to provide a novel SiC single crystal with reduced internal stress while suppressing SiC sublimation. In order to solve the above problems, the present invention provides a method for producing SiC single crystals, including a stress reduction step of heating a SiC single crystal at 1800° C. or higher in an atmosphere containing Si and C elements to reduce internal stress in the SiC single crystal. With this configuration, the present invention can provide a novel SiC single crystal with reduced internal stress while suppressing SiC sublimation.

The present disclosure provides systems and methods for forming block crystals of a metal compound. In some embodiments, a method for forming block crystals of a metal compound may comprise (a) introducing a source metal into a furnace; (b) forming a complete or partial vacuum in the furnace and increasing a temperature of the furnace above a melting point of the source metal to form a liquid flow of the source metal; (c) breaking the liquid flow to generate particles of the source metal; (d) ionizing the particles in an ionization chamber to form ionized particles, wherein the ionization chamber has a temperature above a decomposition temperature of the metal compound; and (e) introducing the ionized particles into a growth chamber comprising a reactive gas that is reactive with the ionized particles, to thereby form the block crystals of the metal compound.

The present disclosure provides systems and methods for forming block crystals of a metal compound. In some embodiments, a method for forming block crystals of a metal compound may comprise (a) introducing a source metal into a furnace; (b) forming a complete or partial vacuum in the furnace and increasing a temperature of the furnace above a melting point of the source metal to form a liquid flow of the source metal; (c) breaking the liquid flow to generate particles of the source metal; (d) ionizing the particles in an ionization chamber to form ionized particles, wherein the ionization chamber has a temperature above a decomposition temperature of the metal compound; and (e) introducing the ionized particles into a growth chamber comprising a reactive gas that is reactive with the ionized particles, to thereby form the block crystals of the metal compound.