Patent ID: 8236103

Claim:
A method for producing a Group III nitride semiconductor crystal, comprising: a first step of supplying a Group III raw material using N 2 for carrier gas at a pressure of 1,000 to 1×10 4 Pa into a reaction furnace having a wall surface and ceiling and having a susceptor to form and grow a polycrystalline Group III nitride semiconductor layer using nitrogen generated by the decomposition of materials adhering to the wall surface or ceiling of the reaction furnace or to the susceptor directly on a sapphire substrate heated to a temperature of 950° C. to 1,200° C. in the absence of a low-temperature buffer layer so that the Group III raw material is excessive in a stoichiometric ratio of the Group III raw material and the Group V raw material; and consecutively, a second step of vapor-phase-growing a Group III nitride semiconductor crystal on the substrate heated to 950° C. to 1,200° C., at a temperature equal to or less than the temperature in the first step using a Group III raw material and a nitrogen raw material.