Fabrication of Ferroelectric Bi₄Ti₃O₁₂ Thin Films by Dipping Pyrolysis of Metal Naphthenates and Micropatterns by an Electron Beam

Abstract

Fabrication of ferroelectric Bi 4 Ti 3 O 12 thin films was carried out by dipping pyrolysis of metal naphthenates. Single-phase Bi 4 Ti 3 O 12 thin films with c -axis orientation perpendicular to the substrate surface were fabricated on Pt plates. They exhibited good ferroelectric properties: coercive field of 7.7 kV/cm and remanent polarization of 8.2 µ C/cm 2 . For the films fabricated on Pt/Ti/ SiO 2 /Si substrates, however, the Bi 2 Ti 2 O 7 phase mainly grew because of Ti diffusion into the bismuth titanate layer during the heat treatment. Fine micropatterns with linewidth of less than 1 µ m in precursors of Bi 4 Ti 3 O 12 were formed by spin-coating, irradiation with an electron beam and development. They were crystallized into the Bi 4 Ti 3 O 12 phase by successive pyrolysis and annealing. The reaction between the metal naphthenate films and energized electrons was studied by IR spectroscopic analysis.