Pt and RuO2 bottom electrode effects on Pb(Zr,Ti)O-3 memory capacitors

This study examines the effects of bottom electrodes for metal ferroelectri c metal (MFM) capacitor applications. We investigated the following paramet ers of bottom electrodes and Pb(Zr0.53Ti0.47)O-3 (PZT) thin films: substrat e temperature, rf power, pas flow rate, Ar/O-2 ratio, electrode material, a nd post-annealing effect. Bottom electrodes grown at 300 degrees C for Pt a nd 200 degrees C for RuO2 exhibited a film resistivity of 10(-4)Omega.cm; h ad a surface roughness of approximately 55 Angstrom and a preferred crystal orientation. Rapid thermal annealing (RTA) treatments on a Pt electrode at 600 degrees C for 30 s improved the resistivity to 5 x 10(-6) Omega.cm and generated the (111) preferred crystal orientation. PZT films exhibited a s trong PZT (101) peak for an optimized Pt bottom electrode and (111); (200): (112) planes without preferred PZT orientations for the RuO2 electrode. A well-fabricated Pd/PZT/Pt capacitor showed a leakage current density in the order of 6 x 10(-5) A/cm(2), a dielectric constant (epsilon(r)) of 365. a remanent polarization (P-r) of 27 mu C/cm(2), and a coercive field (E-c) of 50.5 kV/cm. This paper discusses the bottom electrode propel ties as well as their recommended conditions in memory device applications of thin-film PZT capacitors.