Patent ID: 7212556

Claim:
A semiconductor laser device comprising: a contact layer, which is made of a nitride semiconductor of a first conductivity type and is formed over a substrate; a first cladding layer, which is made of a nitride semiconductor of a first conductivity type and is formed over the contact layer; an active layer, which is made of In y Ga 1−y N and is formed over the first cladding layer; a second cladding layer, which is made of still another nitride semiconductor of a second conductivity type and is formed over the active layer; and an In x Ga 1−x N layer of the first conductivity type is formed between the substrate and the first cladding layer, wherein 0<x<1, 0<y<1 and x≧y in the composition of In, and a substantial portion of light-emitting recombination occurs in the In x Ga 1−x N active layer material.