Lanthanum-modified lead zirconate titanate (PLZT) thin films (50-200nm) were deposited on Pt/SiO
2/Si substrate by metalorganic chemical vapor deposition (MOCVD). The electrical properties of the films were investigated as a function of the La content or the substrate temperature. Ferroelectric PZT (0/50/50) films were obtained at a substrate temperature as low as 500°C, and their electric characteristics were improved with increasing substrate temperature. La was adequately solid-dissolved into the PZT above 650°C. PLZT (15/45/55) films having a thickness of 100nm were found to have good properties for application to capacitors of dynamic random access memory, (DRAM), i, e., effective charge density of 80fF/μm
2, dielectric constant of 1000, SiO
2 equivalent thickness of 0.4nm and leakage current density of 5×10
-8A/cm
2. La addition to PZT was effective in reducing the leakage current with an increase in the registration rate. RuO
2 and IrO
2 bottom electrodes for ferroelectric PLZT films were also investgated. The RuO
2 films were found to serve as effective diffusion barriers for NIT and MgO. Significant interdiffusion at RuO
2/Si and RuO
2/SiO
2 interfaces occurred during the deposition of PLZT films, and annealing of RuO
2 film considerably depressed the interface reactions.
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