Method for producing group-III nitride crystal, group-III nitride crystal, semiconductor device, and device for producing group-III nitride crystal

A method for producing a Group III nitride crystal, comprising:

• a first Group III nitride crystal production process of producing a first Group III nitride crystal by liquid phase epitaxy;
• and
• a second Group III nitride crystal production process of producing a second Group III nitride crystal on the first Group III nitride crystal by vapor phase epitaxy,
• the first Group III nitride crystal production process comprising:
• a seed crystal selection step of selecting a plurality of parts of a preliminarily provided Group III nitride as seed crystals for generation and growth of Group III nitride crystals;
• a contact step of bringing the surfaces of the seed crystals into contact with an alkali metal melt;
• and
• a Group III nitride crystal liquid phase growth step of causing a Group III element and nitrogen to react with each other in a nitrogen-containing atmosphere in the alkali metal melt to generate and grow Group III nitride crystals,
• wherein in the Group III nitride crystal liquid phase growth step, the Group III nitride crystals are bound together by growth of the Group III nitride crystals grown from the seed crystals to produce the first Group III nitride crystal,
• in the Group III nitride crystal liquid phase growth step, the first Group III nitride crystal includes at least one of (a) through holes obtained by not binding some parts of Group III nitride crystals that are adjacent to one another, and (b) concave portions, and
• in the second Group III nitride crystal production process, the second Group III nitride crystal is grown so as to fill or cover the through holes or the concave portions that remain in the first Group III nitride crystal with the second Group III nitride crystal.