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

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.