Patent ID: 8008647

Claim:
A nitride semiconductor device comprising: a p-type nitride semiconductor layer; an n-type nitride semiconductor layer; and an active layer disposed between the p-type and n-type nitride layers and comprising a plurality of quantum barrier layers and quantum well layers deposited alternately on each other, wherein the active layer has a superlattice structure where the quantum barrier layer has a thickness for enabling a carrier injected from the p-type and n-type nitride semiconductor layers to be tunneled therethrough, at least one of the quantum barrier layers has an energy band gap greater than that of the p-type nitride semiconductor layer, the plurality of quantum barrier layers have different energy band gaps in order for the energy band gaps to increase with proximity to the p-type nitride semiconductor layer, each energy band gap of the quantum barrier layers is greater than respective energy band gaps of the quantum well layers, and the quantum barrier having an energy band gap greater than that of the p-type nitride semiconductor is disposed between two of the quantum well layers.