Fatigue and retention of Pb(Zr0.53Ti0.47)O3 thin film capacitors with Pt and RuO2 electrodes

Abstract

Pb(Zr_0.53Ti_0.47)O₃ (PZT) thin films were deposited on Pt and RuO₂ coated Si and MgO substrates using the sol-gel process. Fatigue and retention tests were performed on these samples. The films grown on RuO₂ electrodes are fatigue-free up to nearly 10¹¹ cycles. Their retention life-time extrapolates to more than 10¹⁰ seconds. The fatigue behavior of films grown on Pt electrodes depends on the PZT film orientation. Highly oriented (001) PZT films maintain 50% of their initial P∗r-P⁁r value after 10¹¹ cycles. The randomly oriented films maintain less than 3% of the initial P∗r-P⁁r value after 10¹¹ cycles. However, the retention life-time of both highly oriented and randomly oriented PZT films grown on Pt electrodes extrapolates to higher than 10¹¹ seconds. It appears that fatigue of films grown on RuO₂ is mainly controlled by the film/electrode interface. On the other hand, fatigue of films grown on Pt appears to depend on both the film/electrode interface as well as on bulk effects.