Pt/Bi4Ti3O12(001)/Bi2SiO5(100)/Si(100) structures have been fabricated by the metal-organic chemical vapor deposition (MOCVD) at 500°C. Bi2SiO5film is used as a buffer layer to grow ferroelectric Bi4Ti3O12films because of its relatively high dielectric constant (εr=30). The memory window has a C-V characteristic of about 0.8 V, and the retention time estimated by the zero-bias capacitance for the Pt/100-nm-Bi4Ti3O12/30-nm-Bi2SiO5/Si/Al structure is more than 11 days.