Patent ID: 8293012

Claim:
A method of growing an Al x Ga 1-x N crystal (0<x≦1) by sublimation onto an undersubstrate under a controlled ambient in a reaction vessel, the Al x Ga 1-x N crystal growth method comprising: setting up in the reaction vessel a crystal-growth ambient containing suitable Al x Ga 1-x N crystal-growth precursors and a flowing carrier gas; heating the undersubstrate to a temperature of from 1600° C. to less than 2000° C.; introducing into the ambient at least one Group-IVb element in gaseous form, together with the carrier gas, at a flow rate of 0.005 sccm to 250 sccm, or in solid form together with the Al x Ga 1-x N precursors, so as to incorporate into the ambient at a concentration of from 1 ppm to 15 mass %, for a predetermined period of time extending at least from the start of the growing of the crystal until half the period required for the crystal growth has passed, impurities constituted by the at least one Group-IVb element and thereby form, in the growing of crystal onto the undersubstrate, plural-faceted hexagonal-mouthed pits on the major growth plane of the Al x Ga 1-x N crystal; and controlling the crystal-growth temperature, the concentration of the ambient impurities, and the predetermined time period during which the impurities are introduced into the ambient so as to grow the Al x Ga 1-x N crystal such that the ratio of the total area of the plane of the pit opening to the total area of the major growth plane is at least 30%.