Provided are a semiconductor device having a superlattice semiconductor layer and a method of fabricating the same. The semiconductor device includes a superlattice semiconductor layer in which first material layers and second material layers formed of different materials are alternately stacked. A plurality holes are formed in the first material layers and the second material layers forming a superlattice structure, and the holes are filled with materials of the adjacent material layers. The provided superlattice structure reduces a driving voltage by transferring charges through the holes in the first material layers and the second material layers while maintaining a predetermined optical confinement characteristic.