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

摘要

A dynamic memory device forming a plurality of one-transistor type memory cells in a semiconductor substrate is disclosed. The substrate includes a first portion of one conductivity type, and a second portion of one conductivity type having a higher impurity concentration than that of the first portion and separated from a major surface of the substrate by interposing a part of the first portion. A groove is provided from the major surface into the second portion through the part of the first portion such that a first side wall of the groove is made of the first portion and a second side wall under the first side wall and the bottom of the groove are made of the second portion. A dielectric film of the capacitor is formed on the second side wall and the bottom of the groove, and an electrode of the capacitor is formed on the dielectric film with the groove. One of source and drain regions of the opposite conductivity type of the transfer gate transistor is formed in the first portion, separated from the second portion and contact at its end section to a part of the first side wall of the groove. The electrode of the capacitor is connected to the end section of the source or drain region of the transfer gate transistor.