Evaluation of metalorganic precursors for fabrication of lead-based ferroelectric thin films

Abstract

Eight kinds of metalorganic precursors for metalorganic chemical vapor deposition of lead-based ferroelectric thin films were used to evaluate residual carbon concentration and growth rate of the oxide films. Secondary ion mass spectroscopy measurements indicated that Pb(DPM)2, Zr(O-tC4H9)4, and Ti(O-iC3H7)4 are the most suitable precursors for reducing the carbon concentration in PbO, ZrO2 and TiO2 films, respectively. Using these precursors, a Pb(Zr0.52, Ti0.48)O3 thin film with a residual carbon concentration as low as 0.02mol% was grown at 763 K. Growth rates for various temperature were measured for six precursors. The rates obtained from alcoxide precursors, such as (C2H5)PbOCH2C(CH3)3, Zr(O-tC4H9)4 and Ti(O-iC3H7)4, were saturated in a wide temperature range. An epitaxial PbTiO3 film was obtained on a (100)Pt/(100)MgO substrate at 763K using (C2H5)PbOCH2C(CH3)3 and Ti(O-iC3H7)4 Precise control of the film composition is indispensable for low temperature fabrication of Pb-based ferroelectric thin films.