Patent ID: 7471711

Claim:
A semiconductor light emitting device comprising: a plurality of layers of III-V compound semiconductor materials, each layer including at least N, the plurality of layers including an n-type cladding layer, a p-type cladding layer, and an active layer interposed between said n-type cladding layer and said p-type cladding layer, wherein said n-type cladding layer includes a first n-type layer of n-type Al x Ga 1-x N having an Al composition ratio x satisfying 0.01≦x<0.06, said n-type cladding layer includes a second n-type layer of n-type Al y Ga 1-y N having an Al composition ratio y higher than x, said second n-type layer is separated from said active layer by at least part of said first n-type layer, said p-type cladding layer includes a first p-type layer of p-type Al z Ga 1-z N having an Al composition ratio z satisfying 0.01≦z<0.06, said p-type cladding layer further includes a second p-type layer of p-type AlGaN having an Al composition ratio higher than z, and said second p-type layer is separated from said active layer by at least part of said first p-type layer.