An Important Failure Mechanism in MOCVD (Ba,Sr)TiO 3 thin Films: Resistance Degradation

We have investigated the intrinsic resistance degradation behavior of fiber-textured MOCVD (Ba,Sr)TiO 3 thin films appropriate for use in advanced DRAMs and integrated decoupling capacitors, as a function of applied voltage polarity, thickness, temperature, and dc bias/field. The results suggest that there is a significant stoichiometry effect on the measured resistance degradation lifetimes. The measured degradation lifetime increases as the Ti content is increased from 51.0 to 52.0 at%Ti, and then decreases with higher at%Ti. Predicted resistance degradation lifetimes obtained from both temperature and voltage extrapolations to DRAM operating conditions of 85°C and 1.6 V exceed the current benchmark of 10 years for all of the films studied.