Semiconductor memory device having tree-type capacitor

摘要

A semiconductor memory device such as a DRAM device with a tree-type capacitor having an increased charge storage area includes a substrate, a transfer transistor formed on the substrate and having a drain region, and the tree-type capacitor electrically connected to the drain region. The tree-type capacitor includes a storage electrode shaped in a tree-structure having a trunk-like conductive layer and at least a branch-like conductive layer branching out from the trunk-like conductive layer. A dielectric layer covers the storage electrode and an overlaying conductive layer covers the dielectric layer. The trunk-like conductive layer has one end electrically connected to the drain region of the transfer transistor. The trunk-like conductive layer and the branch-like conductive layer in combination form the storage electrode of the data storage capacitor of the semiconductor memory device and the overlaying conductive layer serves as an opposed electrode to the storage electrode.