Dynamic random access memory device having a plurality of improved one-transistor type memory cells.

摘要

A dynamic random access memory device including one-transistor type memory cells each having a trench capacitor is disclosed. An impurity region of a conductivity type opposite to the substrate and having a net-like plane shape is provided in an inner portion of the substrate, and the impurity region is led-out at a part to the major surface of the substrate. A trench is formed in the substrate from the major surface into the impurity region so that a wall section of the trench is constituted by the impurity region. An dielectric film of the capacitor is formed on the wall section, and a capacitor electrode is formed on the dielectric film and connected to source or drain region of the transistor.