Effects of Ti/Ir top electrodes of PZT capacitors on the hydrogen related degradation

Hydrogen annealing damages on properties of PZT capacitors and a role of Ti /Ir hybrid structure top electrodes on capacitors are investigated in this study. It is demonstrated that the capacitors with Ti/Ir structure top elec trodes improve a resistance against hydrogen related degradation. As the th ickness ratio of Ti/Ir increases, the capacitors show enhanced endurance ag ainst hydrogen damages. Especially, PZT (350nm) capacitors with Ti(80nm)/ I r(20nm) hybrid top electrodes show only 26% decrease in nonvolatile polariz ations (P*(r)) under +/-7V, while 67% of P*(r) of ferroelectric capacitors with Ir top electrodes is reduced after forming gas annealing at 250 degree sC for 10min. Based on the XPS analysis, ferroelectric characteristics of P ZT thin film capacitors are degraded by destruction of Pb-O bond into metal lic Ph due to hydrogen anneal on the catalytic top electrodes (Ir, Pt).