A nitride semiconductor LED improved in lighting efficiency and a fabrication method thereof, in which an n-doped semiconductor layer is formed on a substrate. An active layer is formed on the n-doped semiconductor layer to expose at least a partial area of the n-doped semiconductor layer. A p-doped semiconductor layer is formed on the active layer. A p+-doped semiconductor layer is formed on the p-doped semiconductor layer. An n+-doped semiconductor layer is formed in at least a partial upper region of the p+-doped semiconductor layer via n-dopant ion implantation. The n+-doped semiconductor layer cooperates with an underlying partial region of the p+-doped semiconductor layer to realize a reverse bias tunneling junction. Also, an upper n-doped semiconductor layer is formed on the n+-doped semiconductor layer to realize lateral current spreading. The invention can improve lighting efficiency by using the reverse bias tunneling junction and/or the lateral current spreading.