The present invention provides a method for producing a Group III nitride crystal, capable of producing a Group III nitride crystal in a large size with few defects and high quality. The method is a method for producing a Group III nitride crystal (13), including: a seed crystal selection step of selecting plural parts of a Group III nitride crystal layer (11) as seed crystals for generation and growth of Group III nitride crystals (13); a contact step of causing the surfaces of the seed crystals to be in contact with an alkali metal melt; a crystal growth step of causing a Group III element and nitrogen to react with each other under a nitrogen-containing atmosphere in the alkali metal melt to generate and grow the Group III nitride crystals (13), wherein the seed crystals are hexagonal crystals, in the seed crystal selection step, the seed crystals are arranged so that m-planes of the respective crystals grown from the seed crystals that are adjacent to each other do not substantially coincide with each other, and in the crystal growth step, the plural Group III nitride crystals (13) grown from the plural seed crystals by the growth of the Group III nitride crystals (13) are bound.

A self-supporting substrate includes a first nitride layer grown by hydride vapor deposition method or ammonothermal method and comprising a nitride of one or more element selected from the group consisting of gallium, aluminum and indium; and a second nitride layer grown by a sodium flux method on the first nitride layer and comprising a nitride of one or more element selected from the group consisting of gallium, aluminum and indium. The first nitride layer includes a plurality of single crystal grains arranged therein and being extended between a pair of main faces of the first nitride layer. The second nitride layer includes a plurality of single crystal grains arranged therein and being extended between a pair of main faces of the second nitride layer. The first nitride layer has a thickness larger than a thickness of the second nitride layer.

A production apparatus is used for a solution growth method. The production apparatus includes a seed shaft and a crucible. The seed shaft has a lower end surface to which an SiC seed crystal is attached. The crucible contains an SiC solution. The crucible includes a cylindrical portion, a bottom portion, and an inner lid. The bottom portion is disposed at a lower end of the cylindrical portion. The inner lid is disposed in the cylindrical portion. The inner lid has a through hole and is positioned below a liquid surface of the SiC solution when the SiC solution is contained in the crucible.

A group 13 element source, a flux comprising at least one of an alkali metal and an alkaline earth metal, and an additive being liquid at an ambient temperature are placed in a crystal growing vessel. The crystal growing vessel is heated and pressurized under a nitrogen atom-containing gas atmosphere to form a melt containing the group 13 element source, the flux and the additive. Evaporation of the additive is prevented until the flux is melted. The crystal of the nitride of the group 13 element is then grown in the melt.

Growth of single crystals of lead zirconate titanate (PZT) and other perovskites is accomplished by liquid phase epitaxy onto a substrate of suitable structural and lattice parameter match. A solvent and specific growth conditions for stable growth are required to achieve the desired proportions of Zr and Ti.

Growth of single crystals of lead zirconate titanate (PZT) and other perovskites is accomplished by liquid phase epitaxy onto a substrate of suitable structural and lattice parameter match. A solvent and specific growth conditions for stable growth are required to achieve the desired proportions of Zr and Ti.

Provided are an SiC single-crystal ingot containing an SiC single crystal having a low threading dislocation density and low resistivity; an SiC single crystal; and a production method for the SiC single crystal. The SiC single crystal ingot contains a seed crystal and a grown crystal grown by a solution process in which the seed crystal is the base point, the grown crystal of the SiC single crystal ingot containing a nitrogen density gradient layer in which the nitrogen content increases in the direction of growth from the seed crystal.

Provided are an SiC single-crystal ingot containing an SiC single crystal having a low threading dislocation density and low resistivity; an SiC single crystal; and a production method for the SiC single crystal. The SiC single crystal ingot contains a seed crystal and a grown crystal grown by a solution process in which the seed crystal is the base point, the grown crystal of the SiC single crystal ingot containing a nitrogen density gradient layer in which the nitrogen content increases in the direction of growth from the seed crystal.

A low-resistance p-type SiC single crystal containing no inclusions is provided. This is achieved by a method for producing a SiC single crystal wherein a SiC seed crystal substrate 14 is contacted with a Si—C solution 24 having a temperature gradient in which the temperature falls from the interior toward the surface, to grow a SiC single crystal, and wherein the method comprises: using, as the Si—C solution, a Si—C solution containing Si, Cr and Al, wherein the Al content is 3 at % or greater based on the total of Si, Cr and Al, and making the temperature gradient y (° C./cm) in the surface region of the Si—C solution 24 satisfy the following formula (1): y≧0.15789x+21.52632 (1) wherein x represents the Al content (at %) of the Si—C solution.

A low-resistance p-type SiC single crystal containing no inclusions is provided. This is achieved by a method for producing a SiC single crystal wherein a SiC seed crystal substrate 14 is contacted with a Si—C solution 24 having a temperature gradient in which the temperature falls from the interior toward the surface, to grow a SiC single crystal, and wherein the method comprises: using, as the Si—C solution, a Si—C solution containing Si, Cr and Al, wherein the Al content is 3 at % or greater based on the total of Si, Cr and Al, and making the temperature gradient y (° C./cm) in the surface region of the Si—C solution 24 satisfy the following formula (1): y≧0.15789x+21.52632 (1) wherein x represents the Al content (at %) of the Si—C solution.