A semiconductor device and a method of manufacturing the same, the device including a plurality of lower electrodes on a semiconductor substrate; a support pattern connecting the lower electrodes at sides of the lower electrodes; and a dielectric layer covering the lower electrodes and the support pattern, wherein each of the plurality of lower electrodes includes a pillar portion extending in a vertical direction perpendicular to a top surface of the semiconductor substrate; and a protrusion protruding from a sidewall of the pillar portion so as to be in contact with the support pattern, the pillar portion includes a conductive material, the protrusion includes a same conductive material as the pillar portion and is further doped with impurities.