Single and multilayer ferroelectric PbZr xTi 1− xO 3 (PZT) on BaTiO 3

Abstract

Ferroelectric PbZr x Ti 1− x O 3 (PZT) thin films have been deposited on Pt-coated Si substrates by using r.f. magnetron sputtering. The optimized processing condition to obtain proper stoichiometric PZT, the desired ferroelectric perovskite phase, and better dielectric properties was demonstrated using a PZT target with Pb/(Zr + Ti) ratio of 1.2 and depositing at 350 °C, followed by thermal treatment at 620 °C for 30 min. The structural and electrical properties of the PZT layer were further improved by fabricating a novel multilayer structure which combined the PZT with the nanolayer BaTiO 3. The leakage current density was reduced from 2 × 10 −7 A cm −2 for the single layer structure to 2 × 10 −9 A cm −2 for the multilayer structure at a field of 4 × 10 5 V cm −1, while maintaining the high relative effective dielectric constant of 442. The relative dielectric constant of the PZT film in the multilayer structure was calculated to be about 880.