Disclosed is a semiconductor device for improving a gate induced drain leakage and a method for fabricating the same, and the semiconductor device includes a substrate, a first doped region and a second doped region formed to be spaced apart from each other by a trench in the substrate, a first gate dielectric layer over the trench, a lower gate over the first gate dielectric layer, an upper gate over the lower gate and having a smaller width than the lower gate, and a second gate dielectric layer between the upper gate and the first gate dielectric layer.