Development of CVD-Ru/Ta/sub 2/O/sub 5//CVD-TiN capacitor for multigigabit-scale DRAM generation

We have investigated the electrical properties of metal/Ta/sub 2/O/sub 5//metal (MIM-Ta/sub 2/O/sub 5/) capacitor for multigigabit-scale DRAMs. CVD-TiN film was used as a bottom electrode, whereas PVD-TiN, CVD-TiN and CVD-Ru metals were compared for a top electrode. Our results, including electrical properties and step coverage, showed that a CVD-Ru film is the most promising top electrode material. Based on this result, a CVD-Ru/Ta/sub 2/O/sub 5//CVD-TiN capacitor with cylinder-type storage node was developed, and the cell capacitance of 40fF/cell with the leakage current of 0.1fA/cell at /spl plusmn/1 V applied voltage was accomplished.