Studies of Ir–Ta–O as High Temperature Stable Electrode Material and Its Application for Ferroelectric SrBi2Ta2O9 Thin Film Deposition

An Ir–Ta–O/Ta/Si structure with Ir–Ta–O as electrode and Ta as diffusion barrier layer on silicon substrate has been fabricated. The Ir–Ta–O film was deposited by reactive sputtering using separate Ir and Ta targets in oxygen ambient. Annealing results performed from 500–1000°C in oxygen ambient showed that the Ir–Ta–O film exhibited extraordinary high temperature stability. This film showed good conductivity and integrity even after 5 min annealing at 1000°C. No destructive peeling and hillock formation were observed. By using this film as bottom electrode for depositing ferroelectric SrBi2Ta2O9 thin film at 800°C, good ferroelectric properties were achieved.