Preparation of Bi₄Ti₃O₁₂ films by MOCVD and their application to memory devices

Abstract

Abstract Bi4Ti3O12 thin films were prepared on Pt/SiO2/Si(100) by metalorganic chemical vapor deposition (MOCVD). C-axis oriented Bi4Ti3O12 thin films were grown on Pt/SiO2/Si (100) at 550°C. These films deposited directly on the substrates exhibit very rough surface morphology. However, a Bi4Ti3O12 film with a Bi2Ti2O7 buffer layer on Pt/SiO2/Si(100) exhibits very smooth morphology and has high c-axis orientation. This film shows remanent polarization of 0.6 μC/cm2, coercive field of 13 kV/cm and dielectric constant of 180. MFIS and MFMIS structures which were NDRO ferroelectric memory devices were fabricated using the Bi4Ti3O12 films by MOCVD. In C-V measurement, memory windows by remanent polarization were shown in these structures. When Pt/IrO2/poly-Si was used as a floating gate, some improvements in C-V characteristics were obtained.