Compositional dependence of ferroelectric properties of highly c-axis oriented Bi4−xNdxTi3O12 film capacitors

Highly c-axis oriented neodymium-modified bismuth titanate (Bi4−xNdxTi3O12) films having a variety of neodymium (Nd) contents were successfully grown on Pt/TiO2/SiO2/Si(100) substrates using metal–organic sol decomposition. After systematically examining ferroelectric properties of the c-axis oriented Bi4−xNdxTi3O12 film capacitors as a function of the Nd-content, we concluded that the capacitor with x=0.85 had the largest remanent polarization. The Bi3.15Nd0.85Ti3O12 capacitor fabricated using a top Pt electrode showed well-saturated polarization-electric field (P-E) switching curves with the remanent polarization (Pr) of 51 μC/cm2 and the coercive field (Ec) of 99 kV/cm at an applied voltage of 10 V. More importantly, the Pt/Bi3.15Nd0.85Ti3O12/Pt capacitor exhibited fatigue-free behavior up to 4.5×1010 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.