SEMICONDUCTOR DEVICE

A semiconductor device includes a substrate; lower electrodes on the substrate; a dielectric layer on the lower electrodes; an upper electrode on the dielectric layer; a contact structure connected to the upper electrode; and a wiring layer on the contact structure, wherein the contact structure includes a lower plug, and an upper plug on the lower plug, an upper surface of the lower plug is substantially coplanar with an upper surface of the upper electrode, a first width of the upper surface of the lower plug is narrower than a second width of a lower surface of the upper plug, and the lower surface of the upper plug is in contact with the upper surface of the lower plug.