Patent ID: 8692278

Claim:
A light emitting device comprising: a light emitting structure including a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer between the first and second conductive semiconductor layers; a first ohmic layer physically contacted with an upper surface of light emitting structure; and a second ohmic layer including a light extraction pattern having holes and physically contacted with an upper surface of the first ohmic layer, wherein the second ohmic layer is formed of a material identical to a material of the first ohmic layer, wherein a chemical binding energy between materials constituting of the second ohmic layer is lower than a chemical binding energy between materials constituting of the first ohmic layer, wherein a boundary surface disposed between the first and second ohmic layers is formed by a difference between the chemical binding energies and is a surface adjusting a depth of the light extraction pattern by the difference of the chemical binding energies, wherein the second ohmic layer including the light extraction pattern is located at a higher position than that of the upper surface of the first ohmic layer and the boundary surface, wherein the second ohmic layer including the light extraction pattern is not contacted with the upper surface of the second conductive semiconductor layer, wherein each of the plurality of holes of the second ohmic lager has a depth the same as a thickness of the second ohmic layer, wherein the depth of the light extraction pattern is the depth of the each of the plurality of holes, and wherein the second ohmic layer directly contacts a first electrode, wherein the first and second ohmic layers formed of an oxide layer, and wherein the oxide layer does not contain a nitride.