Semiconductor memory device with capacitor, for DRAM

摘要

A semiconductor memory device has a transfer transistor formed on the substrate, and including drain and source regions. A storage capacitor is electrically coupled to a of drain and source region of the transfer transistor. The storage capacitor comprises: (1) a trunk-like conductive layer with a bottom part electrically coupled to one of drain and source regions, and with one upwardly extending part after extending a distance from the bottom with one approximately upward direction, then extending circumferentially with approximately horizontal direction; (2) a branch-like up conductive layer electrically coupled to above of the trunk-like conductive layer; (3) at least a branch-like down conductive layer with a cross section like L-shape and connected to on down surface of the branch-like up conductive layer. The trunk-like conductive layer, the branch-like up conductive layer, and type branch-like down conductive layer constitute a storage electrode of the storage capacitor. At least one trunk-like conductive layer, with a cross section similar to L shape, whose one end connected to upper surface of the trunk-like conductive layer, the trunk-like conductive layer and branch-like conductive layer constituting a storage electrode of the storage capacitor. A dielectric layer is formed on the truck-like conductive layer and exposed surface of branch-like conductive layer; (6) a upper conductive layer formed on the dielectric, constituting one opposed electrode of the storage capacitor.