DRAM having peripheral circuitry in which source-drain interconnection contact of a MOS transistor is made small by utilizing a pad layer and manufacturing method thereof

摘要

A MOS transistor included in a peripheral circuit of a DRAM has conductive layers for interconnection on respective surfaces of a pair of source.drain regions. The source.drain interconnection layers are electrically connected to the source.drain regions through the conductive layers. One of the pair of conductive layers is formed in the same step as a bit line of a memory cell, by the same material as the bit line. The other one of the pair of conductive layers is formed in the same step as a storage node of a capacitor of the memory cell, by using the same material as the storage node. The pair of conductive layers prevent direct connection between the source.drain interconnection layer and the source.drain regions, so that reduction in size of the source.drain regions can be realized.