Preparation of Bi₄Ti₃O₁₂ thin films by pulsed laser deposition at room temperature

Bismuth titanate (Bi₄Ti₃O₁₂) thin films were successfully deposited on 7.62 cm Pt/Ti/SiO₂/Si(100) substrates by pulsed laser deposition (PLD) technique at room temperature. The microstructure and crystallinity of the annealed thin films appeared to depend on the annealed temperature and time. The prepared films, which were simply treated with a conventional thermal annealing (CTA) or rapid thermal annealing (RTA) process at a relatively high treatment temperature, exhibited a mixed phase structures consisted of Bi₄Ti₃O₁₂ and Bi₂O₇. In contrast, the films, which were annealed by a combined method with conventional thermal annealing and rapid thermal annealing, showed a pure ferroelectric phase Bi₄Ti₃O₁₂, and well-developed crystallinity. The homogeneity about thickness and stoichiometricity of the prepared Bi₄Ti₃O₁₂ films were investigated by Rutherford backscattering spectrometry (RBS) and spreading resistance probe (SRP) technique. The results of transmission electron microscopy (TEM) and SRP experiments indicated that the prepared Bi₄Ti₃O₁₂ thin films had dense, smooth surface morphology and clear, sharp interface as well.