Patent ID: 8466477

Claim:
A semiconductor device, comprising an active layer which comprises a single or multiple quantum well structure having a quantum well having In x1 Ga 1-x1 N (0<x1≦1) and a barrier layer having In x2 Ga 1-x2 N (0≦x2<1, x1>x2); a first semiconductor layer which comprises GaN-based compound semiconductor of first conductive type; a first layer having In 1-x-y1 Ga x Al y1 N (0≦x<1, 0<y1≦1), disposed between the active layer and the first semiconductor layer; a second semiconductor layer which comprises GaN-based compound semiconductor of first conductive type, which is disposed between the first layer and the first semiconductor layer; a third semiconductor layer which comprises In x3 Ga 1-x3 N (0≦x3<1, x2>x3) of first conductive type disposed between the active layer and the first layer; and a second layer having In y2 Ga 1-y2 N (0<y2≦1) layer disposed at least one of between the first layer and the second semiconductor layer and between the first layer and the third semiconductor layer, a band gap of second layer being smaller than those of the first layer, the first semiconductor layer, the second semiconductor layer and the third semiconductor layer.