QUANTITATIVE MEASUREMENT OF SPACE-CHARGE EFFECTS IN LEAD ZIRCONATE-TITANATE MEMORIES

By combining Auger data on the width of an oxygen depletion layer near the Pt electrodes with a modified Langmuir-Child law for the leakage current: I(V) = aV + bV2, we deduce parameters related to the space-charge density and field in 210-nm-thick PbZr1-xTi(x)O3 memories. The results are compared with the space charge fields inferred by Okazaki (approximately 10 kV/cm for PZT), which involve measuring the switching speeds t(s)(E) for positive and negative voltages. Differences in the voltage dependencies of the leakage current are found after fatigue and are related to specific electrochemical processes involving oxygen deposition on electrode surfaces.