US Patent 7826505 III-V group GaN-based compound semiconductor device

A III-V Group GaN-based compound semiconductor device with an improved structure having low current comsumption, high optical output, and a long lifetime is provided. The III-V Group GaN-based compound semiconductor device includes an active layer and a first clad layer and a second clad layer, wherein at least one of the first clad layer and the second clad layer has a superlattice structure formed of a plurality of alternating AlxGa(1-x)N layers (0<x<1) and GaN layers, and the composition ratio of aluminum of the AlxGa(1-x)N layers decreases at a predetermined rate away from the active layer.