Thin dielectric reliability assessment for DRAM technology with deep trench storage node

摘要

The reliability results of thin gate oxide and nitride-oxide film development for application in dynamic random access memories are presented. Data and observations from this technology development are embedded in general state-of-the-art review. Therein features of lifetime extrapolation models are discussed. Process and test structures as well as the stress procedure are briefly described. Among the data presented are long term stress results supporting the anode hole injection model down to 5 V, breakdown propagation results and the soft breakdown of 6 nm oxide, which allows detection of device degradation due to Fowler-Nordheim stress. Furthermore the dependence of the voltage acceleration on oxide thickness is shown for the range of less than 2-10 nm oxide thickness. The importance of physical failure analysis is emphazised.