Provided is a semiconductor device including a substrate including a cell array area and a peripheral circuit area and including a plurality of first active areas defined in the cell array area and at least one second active area defined in the peripheral circuit area; a plurality of bit lines arranged in the cell array area of the substrate and extending in a first direction; a plurality of cell pad structures arranged between the bit lines and each including a first conductive layer, a first intermediate layer, and a first metal layer that are sequentially arranged on a top surface of the first active area; and a peripheral circuit gate electrode disposed on the peripheral circuit area of the substrate and including a second conductive layer, a second intermediate layer, and a second metal layer sequentially arranged on the at least one second active area.