Patent ID: 7846820

Claim:
A process for producing a nitride semiconductor, comprising: step (A) of providing a nitride semiconductor substrate; step (B) of forming on the nitride semiconductor substrate a plurality of stripe ridges having upper faces which are parallel to a principal face of the nitride semiconductor substrate, and thereafter covering regions of the principal face of the nitride semiconductor substrate where the plurality of stripe ridges are not formed and side faces of each stripe ridge with a selective-growth mask, so as to expose the upper face of each stripe ridge; step (C) of selectively growing Al x Ga y In z N crystals (0≦x, y, z≦1: x+y+z=1) on the upper faces of the plurality of stripe ridges, the Al x Ga y In z N crystals containing an n-type impurity at a first concentration; and step (D) of growing an Al x′ Ga y′ In z′ N crystal (0≦x′, y′, z′≦1: x′+y′+z′=1) on the Al x Ga y In z N crystals, the Al x′ Ga y′ In z′ N crystal containing an n-type impurity at a second concentration which is lower than the first concentration, and linking every two adjoining Al x Ga y In z N crystals with the Al x′ Ga y′ In z′ N crystal to form one nitride semiconductor layer.