A semiconductor device including a substrate; bottom electrodes on the substrate, each bottom electrode including a first region and a second region, the second region containing an additional element relative to the first region; a first supporting pattern on the substrate and in contact with a portion of a side surface of each bottom electrode; a top electrode on the bottom electrodes; a dielectric layer between the bottom electrodes and the top electrode; and a capping layer between the bottom electrodes and the dielectric layer, the capping layer covering a top surface and a bottom surface of the first supporting pattern, wherein the second region is in contact with the capping layer, and the capping layer and the dielectric layer include different materials from each other.