Effects of chemical stability of platinum/lead zirconate titanate and iridium oxide/lead zirconate titanate interfaces on ferroelectric thin film switching reliability

摘要

We report a comparative study focusing on characterization of the ferroelectric film/top electrode interface and electrical measurements, for nominally identical Pb(Zr,Ti)O_3 (PZT) films with either Pt or IrO_2 top electrodes. We find that the superior reliability and polarization switching behavior of capacitors with IrO_2 top electrodes are associated with the inert nature of lead present near the PZT film surface during top electrode processing. In contrast, lead near the PZT surface reacted with the Pt at the film/Pt-top-electrode interface, possibly creating a stable Pb_xPt_(1-x)phase, and this reaction appeared to cause thickening of a nonferroelectric layer at the PZT/electrode interface.