Patent ID: 7741654

Claim:
A Group III nitride semiconductor optical device comprising: an active layer made of a Group III nitride semiconductor; a current-confining layer provided over the active layer; an opening for current injection provided as a current injection region in the current-confining layer; a cladding layer of a superlattice structure provided on an upper part of the current-confining layer and the opening for current injection; a contact layer provided on an upper part of the cladding layer; and an electrode provided on a surface of the contact layer, wherein the dislocation density of the cladding layer in a region directly above the current-confining layer is higher than the dislocation density of the cladding layer in a region directly above the opening for current injection, wherein the current-confining layer is made of Al x Ga y In 1-x-y N (0.4≦×≦1, 0≦y≦0.6, 0 ≦×+y≦1), wherein the thickness of the current-confining layer is selected in the range of 50 nm or thicker, but 200 nm or thinner, wherein the Group III nitride semiconductor optical device further comprises an insulating layer having an opening that is provided on the surface of the contact layer, wherein the electrode is provided so as to be in contact with the contact layer exposed in the opening, wherein the opening for current injection of the current injection region is in stripe shape, wherein the current-confining layer is constituted by a pair of stripe-shaped current-confining layers provided on both sides of the stripe-shaped opening for current injection, and wherein each of ends of the opening provided in the insulating layer is positioned over the current-confining layers.