Composition and Crystal Phase Control of Chemical-Vapor-Deposited Pb(Zr_x,Ti_1-x)O₃ Films on Various Oxide Electrodes with Reactants Pb(C₂H₅)₄, Zr(O-t-C₄H₉)₄, Ti(O-i-C₃H₇)₄ and O₂

Abstract

The film-composition-determining path of lead zirconate titanate chemical vapor deposition (PZT-CVD) in a cold-wall reactor operated at 773 K was studied using Pb(C2H5)4, Zr(O-t-C4H9)4, Ti(O-i-C3H7)4, and O2 as the reactants. The differences in composition and crystalline properties of PZT films grown on various oxide substrate surfaces under the same reaction conditions revealed that a heterogeneous reaction between Pb(C2H5)4 and O2 to form PbO as an intermediate plays a decisive role in determining the PZT composition in this multi-component CVD system. To explain these substrate-dependent differences in growth behavior, a reaction model was then developed that utilizes the electronegativity difference of O between the PbO and the oxide substrate as the affinity index for chemisorption of Pb(C2H5)4. This model explains well why PZT grown on IrO2 (with a strong affinity) tends to be Pb-rich in composition but Pb-deficient on (La,Sr)CoO3 (with a weak affinity).