Patent ID: 7481881

Claim:
A method of manufacturing GaN crystal substrate, comprising: a step of forming an aperture-window-defining mask layer onto a growth substrate; a step of growing onto the mask layer GaN crystal by a hydride vapor-phase epitaxy employing GaCl and NH 3 source gases; and a step, in said step of growing GaN crystal, of controlling the partial pressure of the GaCl source gas to be from 0.5 kPa to 1.5 kPa, the partial pressure of the NH 3 source gas to be from 5.0 kPa to 10 kPa, and the crystal-growth temperature to a predetermined value; wherein the GaCl and NH 3 source-gas partial pressures are controlled, and the crystal-growth temperature is predetermined so as to form in the crystal-growth surface facet-plane-defining pits that enlarge diametrically as the crystal grows, yet such that the pit-size increase factor of the pits is in the range of from 5% to 20%, and letting the growth rate of the c-plane be V c and the growth rate of the facet plane be V F , such that V c ≦V F sin θ, whereby the pits in the crystal-growth surface do not coalesce.