Semiconductor memory device having a plurality of memory cells of single transistor type.

摘要

A new memory device of single transistor type is disclosed. A substrate (10) has the surface portion (12) of low impurity concentration and the inner portion (11) of high impurity concentration, and a trench (60) is formed in the substrate from the surface portion into the inner portion such that the trench surrounds a cell section (50) of the substrate. A switching transistor is formed in the surface portion at the cell section, and a capacitor is formed in the trench such that a MOS type capacitor is constituted by a capacitor electrode (13), the lower side wall (40) by the inner portion of the substrate and an insulating film (30) therebetween. A bit line (24) is connected to a conductive layer (22) provided at the upper part of the trench, and the conductive layer is connected to the source or drain region (20, 21) of the transistor.