Process and device technologies for 1 Gbit dynamic random-access memory cells

This article discusses the technological issues involved with continuing the miniaturization of dynamic random-access memory cells into the gigabit era. Ever-smaller giga-generation dynamic random-access memory cells require three-dimensional high-charge density capacitors with high-ε insulating films, leading to the need for further improvements in lithographic resolution for ever-smaller, higher aspect ratio memory cells, and planarization technologies for reducing the memory-cell height. This article demonstrates two technologies for meeting these two requirements: high acceleration energy electron-beam lithography and KrF excimer-laser phase-shift photolithography, and plate-wiring merge technology. Metal–insulator–metal 1.6 nm Ta2O5 CROWN capacitors and single Si3N4 spacer OSELO isolation technology for an experimental 1 Gbit dynamic random-access memory chip are also discussed.