PbO_x phase separation in PbZr_0.52Ti_0.48O₃ based capacitors made using sol-gel films with high Pb precursor excess

We present a study of the impact of Pb excess content on electrical performance of lead zirconate titanate (PbZr 0.52 Ti 0.48 O 3 , PZT) thin-film capacitors. High Pb excess eliminates the ZrOx interface layer between the PZT and the electrode but also reduces the breakdown field, while the linear dielectric character of the capacitor response increases with Pb excess. The chemical sensitivity of hard x-ray photoelectron spectroscopy with in situ bias provides direct evidence of a polar but the non-ferroelectric PbO x phase in the bulk of the sol-gel film. The phase has a distinct core level signature and is consistent with the dielectric response at low field, which becomes more ferroelectric at higher field, as well as the lower remanent polarization and breakdown field.