Electrical Properties of Bi4-xLaxTi₃O₁₂Ferroelectric Thin Films Prepared by Metalorganic Decomposition Method

Bi 4- x La x Ti 3 O 12 (BLT) ferroelectric thin films were prepared on a Pt/TiO x /SiO 2 /Si substrate using metalorganic decomposition (MOD) method, and their electrical properties were evaluated with thickness, composition and crystallization annealing temperature. Irrespective of the preparation conditions, BLT films were c -axis oriented, and had a dense surface morphology without pore to produce smooth Pt/BLT/Pt interfaces of capacitor. The film thickness was controlled as 90 nm to obtain a low coercive voltage (2 V c ) without the problem of capacitor short-fail. The proper composition of Bi 3.35 La 0.85 Ti 3 O 12 was selected for the largest switching polarization ( P * - P ∧ ), good fatigue endurance and a low leakage current density ( J L ). After crystallization annealing at 700°C, the optimized film of 90 nm Bi 3.35 La 0.85 Ti 3 O 12 showed the good electrical properties, such as 2 V c of 2.0 V, P * - P ∧ of 13 µC/cm 2 , J L of 1 × 10 -6 A/cm 2 at a applied voltage of 3 V and no polarization loss up to 1 × 10 11 fatigue cycles, for ferroelectric random access memory (FeRAM) application.