Composition Control of Pb(ZrxTi1-x)O3 Thin Films Prepared by Metalorganic Chemical Vapor Deposition

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Abstract
PbO, ZrO2, TiO2 and Pb(Zr x Ti1-x )O3 (PZT) films were prepared by metalorganic chemical vapor deposition (MOCVD) using Pb(C11H19O2)2, Zr(O·t-C4H9)4, Ti(O·i-C3H7)4 and O2 as source materials. The deposition rates of the constituent metals of Pb(Zr x Ti1-x )O3 (PZT) film were investigated as functions of the input gas flow rate of the source materials and the deposition temperature. Composition ratios of the PZT film became constant when the Ar carrier gas flow rate of the Pb source was above 100 cm3/min at 500°C. This suggests that a self-correcting composition region exists for this input gas composition at 500°C. The deposition rates of each of the constituent metals of the PZT films were quite different from those in the corresponding single-oxide films, PbO, ZrO2, and TiO2 films. Therefore, the composition ratio of the PZT film could not be estimated from the deposition rates of the corresponding single-oxide films. The deposition temperature dependence of the deposition rates of Ti and Zr in the PZT films was almost the same. This results in the Zr/(Zr+Ti) ratio being independent of the deposition temperature. However, the deposition behavior of Pb was different from those of Ti and Zr. Therefore, the Pb/(Pb+Zr+Ti) ratio must be adjusted by changing the input gas flow rate of the Pb source when the deposition temperature is changed.