In one aspect, the invention includes a method of forming circuitry comprising: a) forming a capacitor electrode over one region of a substrate: b) forming a capacitor dielectric layer proximate the electrode; c) forming a conductive diffusion barrier layer, the conductive diffusion barrier layer being between the electrode and the capacitor dielectric layer; d) forming a conductive plug over another region of the substrate, the conductive plug comprising a same material as the conductive diffusion barrier layer; and e) at least a portion of the conductive plug being formed simultaneously with the conductive diffusion barrier layer. In another aspect, the invention includes an integrated circuit comprising a capacitor and a conductive plug, the conductive plug and capacitor comprising a first common and continuous layer. In yet another aspect, the invention includes a circuit construction comprising: a) a substrate having a memory array region and a peripheral region that is peripheral to the memory array region; b) a capacitor construction over the memory array region of the substrate, the capacitor construction comprising a storage node, a capacitor dielectric layer and a cell plate layer; the capacitor dielectric layer being between the storage node and the cell plate layer; and c) an electrical interconnect over the peripheral region, the interconnect being electrically connected to the cell plate layer and extending between the cell plate layer and the substrate.