Investigation of PtNb Alloy Electrodes for Ferroelectric Pb(Zr,Ti)O_3 Thin Film Capacitors

摘要

PtNb alloy thin films with Nb content of 4.5 mass% and Pt films were fabricated on SiO_2/Si substrates by DC magnetron sputtering and their thermal stability was investigated. The resistivity of as-deposited PtNb films was approximately 40 μΩcm and gradually decreased to 30 μΩcm with an increasing of the annealing temperature. These values were double that of the resistivity of Pt films, but lower than the resistivity of conventional oxide electrodes. The surface morphology of PtNb films did not change at any annealing temperature below 650℃ while the recrystallization and the grain growth were observed in Pt films above 550℃. The Pb(Zr,Ti)O_3 (PZT) thin films formed on PtNb electrodes by the chemical solution deposition (CSD) method at 650℃ consisted of large plate-like crystals, while the PZT thin films on Pt electrodes had a cluster-like structure which consisted of small grains and pores. The endurance property of PZT capacitors was significantly improved by using PtNb electrodes.