Enhancement of polarization in bismuth titanate thin films co-modified by La and Nd for non-volatile memory applications

Bismuth titanate thin films co-modified by La and Nd, Bi3.15(La0.425Nd0.425)Ti3O12 (BLNT) were grown on Pt/Ti/SiO2/Si(100) substrates by metalorganic solution decomposition method. The co-substitution leads to structural distortion with enhanced remanent polarization. The BLNT film capacitor with a top Pt electrode showed a large remanent polarization (2Pr) of 90 μC/cm2 at an applied voltage of 10 V, which is higher than that of highly c-axis oriented BLT, and comparable with BNdT thin films. The BLNT films exhibited a fatigue-free behavior up to 1×109 switching cycles at a frequency of 1 kHz. These experimental results reveal that BLNT thin films can be used as capacitors in ferroelectric random access memory applications.