Deposition of Bi4−xLaxTi3O12 films by direct liquid injection-metalorganic chemical vapor deposition

Abstract

Deposition of Bi4−xLaxTi3O12 (BLT) films with direct liquid injection-metal organic chemical vapor deposition using a single-mixed solution of Bi(Ph)3, Ti(dmae)4, and La(tmhd)3- pentamethyldiethylenetriamine was studied. On Pt surface, the deposition rate of the BLT film was almost independent of the deposition temperature. Above 425 °C, it appears that precursors were dissociated in the gas phase and the deposition rate was decreased. The film composition could be controlled by adjusting the concentration of Bi and La precursors in the solution through the competitive substitution of Bi and La element in the Bi site of Bi-layer perovskite structure (Bi4 Ti3 O12). Fatigue-free and highly c-axis oriented BLT thin films were grown on Pt/TiO2/SiO2/Si at the deposition temperature of 400 °C. For the film annealed at 650 °C, the remanent polarization (2Pr) and coercive field (Ec) were 12 μC/cm2 and 56 kV/cm, respectively. The BLT capacitors did not show any significant fatigue up to 4×1010 cycles at a frequency of 1 MHz.