EVALUATION OF ELECTRICAL-PROPERTIES AND SIMS PROFILES ON FORMING GAS(N-2-H-2) ANNEALED PT PZT/PT CAPACITORS/

PZT is promising material for FeRAM. It has a serious problem on the C MOS wafer process that electrical properties are degraded with forming gas annealing. Recently, the degradation mechanism has been investiga ted actively, but it isn't understood enough. We studied electric prop erties and SIMS profiles after N-2-H-2 annealing on Pt/PZT/Pt capacito rs. For the first time, we found that hydrogen atoms increased in PZT layer and oxygen atoms decreased in upper Pt layer after N-2-H-2 annea ling. The nonvolatile polarization (Pnv) decreased in proportional to the hydrogen content in PZT. And the annealing induced the voltage shi ft of hysteresis when capacitors polarized before anneal. On the other hand, a clear corelation was not seen between Pnv and the oxygen cont ent in Pt; however, the adhesion of Pt/PZT became poor in case of a sm all amount of oxygen in Pt. The oxygen in Pt has a contribution to the adhesion of Pt/PZT.