US Patent 11289625 Light emitting diode of improved light extraction rate

A light emitting diode includes a first type semiconductor layer, an active layer, a second type semiconductor layer, a patterned electrode layer, a flat layer and a reflective layer. The active layer is disposed on the first type semiconductor layer. The second type semiconductor layer is disposed on the active layer. The second type semiconductor layer includes a first surface and a second surface having a first arithmetic mean roughness. The patterned electrode layer is disposed on the second surface of the second type semiconductor layer. The planarization layer is disposed on the second type semiconductor layer. The planarization layer includes a third surface and a fourth surface. The third surface is in contact with the second surface of the second type semiconductor layer. The fourth surface has a second arithmetic mean roughness that is less than the first arithmetic mean roughness.