The effect of metallic oxide layer on reliability of lead zirconate titante thin film capacitors

The fatigue characteristics of Pb(Zr,Ti)O3 (PZT) thin film capacitors with various metallic oxide layers between PZT and Pt electrodes have been investigated. Various metallic oxides such as MgO, CeO2, Mn2O3, and (La,Sr)CoO3 (LSCO) were used. These oxides range over a wide variety of non-stoichiometry, i.e. from stoichiometric insulating oxides to non-stoichiometric conducting oxides. These PZT thin film capacitor stacks consist of Pt/metallic oxide/PZT (2000 إ)/LSCO (700 إ) /Pt/Ti/SiO2/Si, in which the PZT layers grown on these LSCO layers were the randomly oriented perovskite phase. Therefore, the Pt/PZT interface was modified with the metallic oxide layers. As the degree of non-stoichiometry in the metallic oxide film increases, the fatigue resistance of the PZT thin film capacitors tends to increase. This result suggests that non-stoichiometric oxides alleviate the accumulation of oxygen vacancies near the interface which has been proposed as a primary cause of fatigue in lead base perovskite thin films. It is suggested that the change in the oxygen stoichiometry near the modified interface via oxygen transport or surface reaction affects the fatigue characteristic of PZT thin film capacitors.