Characterization of lead zirconate titanate heterolayered thin films prepared on Pt/Ti/SiO 2/Si substrate by the sol–gel method

Abstract

Ferroelectric lead zirconate titanate (PZT) heterolayered thin films were fabricated by the spin coating method on a Pt/Ti/SiO 2/Si substrate using PZT (10/90) and PZT (90/10) metal alkoxide solutions. All PZT heterolayered films showed a uniform grain structure without the presence of rosette structures. It can be assumed that the lower PZT layers played the role of a nucleation site or a seeding layer for the formation of the upper PZT layer. Zr and Ti atoms were diffused into the adjacent PZT layers and the Pb diffusion into the Pt bottom electrode was observed. The Pb atoms that diffused into the Pt electrode were mainly distributed at the surface of Pt electrode beneath the PZT/Pt interface. Below the Pt layer, a metallic Ti layer was transformed into a Ti oxide layer by the diffusion of oxygen from the atmosphere and SiO 2. The PZT/Pt interfacial layer showed a microstructure characterized by a grain phase surrounded by a Pb-deficient pyrochlore matrix phase. The heterogeneous interfacial layer at PZT film interfaces was caused by diffusion of Zr and Ti elements during the PZT film growth.