A semiconductor device including a lower contact pattern including a first metal, an upper contact pattern including a second metal, a first resistivity of first metal being greater than a second resistivity of the second metal, and a metal barrier layer between the lower contact pattern and a lower portion of the upper contact pattern, the metal barrier layer including a third metal, the third metal being different from the first and second metals may be provided. A lower width of the upper contact pattern may be less than an upper width of the lower contact pattern.