Preparation of Bi4Ti3O12 Thin Film on Si(100) Substrate Using Bi2SiO5 Buffer Layer and Its Electric Characterization

Abstract

Bi₄Ti₃O₁₂ thin films 100, 200 and 400 nm thick were prepared on Si(100) substrates using 30 nm Bi₂SiO₅ as a buffer layer, by metalorganic chemical vapor deposition (MOCVD). It was demonstrated that c-axis-oriented Bi₄Ti₃O₁₂ films can be grown on Si substrates at 500°C using an a-axis-oriented Bi₂SiO₅ buffer layer. The dielectric constant of the Bi₂SiO₅ film was estimated to be about 30 from capacitance measurements. The capacitance-vs-voltage (C-V) characteristics of Pt/Bi₄Ti₃O₁₂/Bi₂SiO₅/Si (MFIS) structures had ferroelectric switching properties, and the memory windows were about 0.8, 1.5 and 2.9 V for 100, 200 and 400 nm Bi₄Ti₃O₁₂, respectively. Furthermore, it was shown that the capacitance at zero bias remains almost constant for 12 days. This suggests that Bi₄Ti₃O₁₂/Bi₂SiO₅/Si MFIS structures have excellent memory retention properties.