Patent ID: 8023545

Claim:
A semiconductor light emitting device, comprising a conductive semiconductor substrate on which at least the following layers are stacked in the order listed below: a first clad layer; an active layer which includes at least one highly strained quantum well layer having a compressive strain amount not less than 1% with respect to the conductive semiconductor substrate; and a second clad layer, wherein the apparatus further comprises a strain buffer layer adjacently formed on the active layer and includes a layer having a compressive strain amount not greater than the strain amount of the active layer, wherein sum S of the product of the compressive strain amount and layer thickness of each layer included in the strain buffer layer represented by Formula (1) below satisfies Formula (2) below: S=Σ (Δ i×Ti ) (1) 0.2%·μm≧ S≧ 0.02%·μm (2) where, Δi and Ti are the compressive strain amount (%) and layer thickness (μm) of i th layer of the strain buffer layer from the active layer side, and Σ means to sum up the product in each layer included in the strain buffer layer.