Ferroelectric properties of highly c-axis oriented Bi 4− xLa xTi 3O 12 film-based capacitors

Abstract

Highly c-axis oriented lanthanum-modified bismuth titanate (Bi 4− x La x Ti 3O 12) films having a variety of lanthanum (La) contents were grown on Pt/TiO 2/SiO 2/Si(100) substrates using metal-organic sol deposition and subsequent annealing at 650 °C for 1 h. After systematically examining the ferroelectric properties of Bi 4− x La x Ti 3O 12 films as a function of the La-content, it was concluded that the film with x=0.85 had the largest remanent polarization in the direction parallel to the c-axis. The Pt/Bi 3.15La 0.85Ti 3O 12/Pt capacitor showed a well-saturated polarization–electric field (P–E) switching curve with the switching remanent polarization (2 P r) value of 33 μC/cm 2 and the coercive field ( E c) of 68 kV/cm at an applied voltage of 10 V. More importantly, the capacitor exhibited fatigue-free behavior up to 6.5×10 10 read/write switching cycles at a frequency of 1 MHz. The capacitor also demonstrated an excellent charge-retaining ability and a strong resistance against the imprinting failure.