Abstract: A method for producing a Group III nitride semiconductor includes feeding a nitrogen-containing gas into a molten mixture of a Group III metal and a flux placed in a furnace, to thereby grow a Group III nitride semiconductor on a seed substrate, wherein the Group III nitride semiconductor is grown on the seed substrate, while controlling the surface modification weight ratio, which is defined as the ratio of the weight of Na including a portion surface-modified through oxidation or hydroxidation to the weight of Na when the surface thereof has no surface-modified portion as a reference weight, with Na serving as the flux.

Abstract: A method for producing a Group III nitride semiconductor includes feeding a nitrogen-containing gas into a molten mixture of a Group III metal and a flux placed in a furnace, to thereby grow a Group III nitride semiconductor on a seed substrate. At least an oxidation amount of Na, serving as the flux, is controlled outside the furnace, and the controlled Na is fed into the furnace.

Abstract: The present invention suppresses anomalous growth of a Group III nitride semiconductor at the periphery of a seed substrate. The invention is directed to a method for producing a Group III nitride semiconductor including feeding a nitrogen-containing gas into a molten mixture of a Group III metal and a flux placed in a furnace, to thereby grow a Group III nitride semiconductor on a seed substrate. The oxygen concentration of the furnace internal atmosphere is elevated after the growth initiation temperature of the Group III nitride semiconductor has been achieved. In a period from the initiation of the growth to a certain timing, the oxygen concentration of the furnace internal atmosphere is controlled to 0.02 ppm or less, and thereafter, to greater than 0.02 ppm and 0.1 ppm or less.