Disclosed is a semiconductor device comprising a substrate including a first region and a second region, a first gate pattern on the substrate of the first region, and a second gate pattern on the substrate of the second region. The first gate pattern comprises a first high-k dielectric pattern, a first N-type metal-containing pattern, and a first P-type metal-containing pattern that are sequentially stacked. The second gate pattern comprises a second high-k dielectric pattern and a second P-type metal-containing pattern that are sequentially stacked.