Fabrication of ferroelectric Bi₄Ti₃O₁₂ thin films and micropatterns by means of chemical solution decomposition and electron beam irradiation

Abstract

Fabrication of ferroelectric Bi₄Ti₃O₁₂ thin films were carried out by chemical solution decomposition process. Bismuth and titanium octylates were used as starting materials. Precursor solutions were prepared by mixing the octylates with Bi:Ti molar ratio of 5.2:3.0. The films were crystallized into single-phase Bi₄Ti₃O₁₂ with c-axis orientation by heat treatment at 800°C for 30 min in air. The resultant film with a thickness of 400 nm consisted of large platelike crystals and exhibited ferroelectric properties; the remanent polarization of 0.4 μC/cm² and the coercive field of 20 kV/cm. Fabrication of ferroelectric Bi₄Ti₃O₁₂ micropatterns were also carried out by electron-beam-induced patterning process using liquid sources. The fine Bi₄Ti₃O₁₂ micropatterns with a linewidth of 0.3 μm were obtained. To promote crystal growth, heat treatment in O₂ gas with a pressure of 0.3 MPa was carried out. Resultant micropatterns were, however, polycrystals consisted of small grains.

Key Words:

• ferroelectric
• Bi₄Ti₃O₁₂
• metal octylate
• thin film
• micropatterning
• beam-induced deposition