Control of Crystal Orientations and Its Electrical Properties of PZT/Ru and PZT/RuO2 Thin Films by MOCVD

Abstract

AbstractRu and RuO2 thin films were deposited on (100)LaAlO3 (LAO), (100)MgO and (111)Pt/Ir/ SiO2/Si substrates byMOCVD. Pb(Zr,Ti)O3 (PZT) was fabricated on Ru/LAOand RuO2/LAO. Ru thin films deposited at 400°C or higher on LaAlO3 and MgO showed epitaxial (001) crystal orientation. (001) uniaxial Ru was deposited on Pt/Ir/SiO2/Si. RuO2 thin films with (100) orientation were deposited both on LaAlO3 and Pt/Ir/SiO2/Si. (110)-oriented RuO2 thin film was deposited on MgO. Epitaxial RuO2 thin films were deposited on LaAlO3 and MgO at 400°C or higher. The smoothest surfaces and the lowest room-temperature electrical resistivities were obtained at 400°C and 450°C, respectively. The crystal orientations and electrical properties of the PZT thin films deposited on the Ru and RuO2 thin films at 550°C were strongly affected by the crystal orientations and microstructure of the Ru and the RuO2 films. Rhombohedral Pb(Zr0.6Ti0.4)03 thin films deposited on RuO2/LAOand Ru/LAO at 550°C with lower growth rate (1.2nm/min) showed (110) and (001) orientation, respectively. The remanent polarization value (Pr) for (001) PZT on Ru/LAO was ∼70 μC/cm2. (110) PZT on RuO2/LAO showed lower Pr (∼30 μC/cm2), but showed low leakage current (10-9 A/cm2 at 500kV/cm). The dense microstructures and smooth surface structures brought the good leakage characteristics.