High-Quality GaN Crystal Growth Using Flux-Film-Coated LPE with Na Flux

Flux-film-coated liquid phase epitaxy (FFC-LPE), in which a liquid Ga-Na film is coated on a GaN surface, is used for the synthesis of GaN crystals. The addition of a minor amount of additives of group II elements (Ca and Sr) shows the effects that the inclusions are eliminated from a GaN crystal while significantly reducing dislocation density during FFC-LPE. By performing FFC-LPE growth with Ca and Sr additives, the wettability of the seed crystal and the flux is greatly improved, resulting in the achievement of the single molecule step growth mode. Inclusions that are inevitably included in the GaN crystal through the conventional Na flux method can be prohibited by the realization of this growth mode. The dislocation density of the seed-GaN decreases to 2.5 x 10(6)cm(-2)(<1/100th of the seed crystal) after the growth thickness of 10 mu m by means of the FFC-LPE method.