Oxygen vacancy as fatigue evidence of La _0.5 Sr _0.5 CoO ₃ /PbZr _0.4 Ti _0.6 O ₃ /La _0.5 Sr _0.5 CoO ₃ capacitors

Abstract

La0.5Sr0.5CoO3 (LSCO) films grown on SrTiO3 substrates, cooled at reduced oxygen pressures, ranging from 8×104 to 1×10−4 Pa, from the depostion temperature, are used as the bottom electrodes of PbZr0.4Ti0.6O3 (PZT) capacitors to study the impact of oxygen stoichiometry of the LSCO bottom electrodes on the structural and physical properties of LSCO/PZT/LSCO capacitors. It is found that the tetragonality, polarization and fatigue-resistance of PZT films decrease with the decrease of the cooling oxygen pressure. Almost 60% polarization degradation occurs for the PZT capacitor with the LSCO bottom electrode cooled in 1×10−4 Pa oxygen up to 1010 switching cycles, indicating that the oxygen vacancy of the bottom electrode can result in fatigue of the LSCO/PZT/LSCO capacitor.