Transistor on capacitor (TOC) cell with quarter pitch layout for 0.13 /spl mu/m DRAMs and beyond

Abstract

We present a new trench type cell, transistor on capacitor (TOC) cell with 1/4 pitch layout. Two kinds of new idea have been implemented. One is that the density of the trench capacitor is closest packed by introducing 1/4 pitch layout. The other is that the transfer transistor is fabricated over the trench capacitor by introducing the newly developed epitaxial growth and Chemical Mechanical Polish (CMP) technologies. As a result, trench opening can be enlarged without reducing the gate length of the transfer transistor.