Patent ID: 8723202

Claim:
A semiconductor light emitting device, comprising: a substrate; a first conductive semiconductor layer on the substrate; an active layer on the first conductive semiconductor layer; a second conductive semiconductor layer on the active layer, the second conductive semiconductor layer including a top surface and a bottom surface opposing to the top surface, the bottom surface being adjacent to the active layer; a roughness layer disposed on the second conductive semiconductor layer and including Al material; a conductive layer including Ti material on the roughness layer; and at least one of a first AlGaN based semiconductor layer disposed on the active layer and a second AlGaN based semiconductor layer disposed under the active layer, wherein the first conductive semiconductor layer includes a first GaN layer and the second conductive semiconductor layer includes a second GaN layer, wherein the second conductive semiconductor layer includes a plurality of apexes on the top surface, the distance between at least two apexes of the plurality of apexes is about 0.3 μm to about 1.0 μm, wherein the conductive layer includes a lower surface having a shape corresponding to the top surface of the second conductive semiconductor layer, and wherein the roughness layer includes a lower surface having a shape corresponding to the top surface of the second conductive semiconductor layer.