A Gbit-scale DRAM stacked capacitor technology with ECR MOCVD SrTiO₃ and RIE patterned RuO₂/TiN storage nodes

摘要

A new stacked capacitor technology with high permittivity ECRMOCVD SrTiO₃ films on 1 Gbit compatible RuO₂/TiNstorage nodes was developed for Gigabit-scale DRAMs. A cell capacitanceof 25 fF and leakage current density of 8×10-7A/cm2 can be achieved with this capacitor technology, using0.5 μm high stacked storage electrodes in a 0.125 μm2capacitor area. Fine storage RuO₂/TiN electrodes werepatterned down to 0.2 μm by electron beam lithography and RIE usingan O₂-based etching mixture. A new low temperature ECR MOCVDtechnique was also developed to prepare highly reliableSrTiO₃ films to be used on the storage electrode sidewalls