Structure and ferroelectric properties of Bi_(3.25)La_(0.75)Ti_3O_(12) and Bi_(3.25)Nd_(0.75)Ti_3O_(12) thin films prepared by a MOD method

摘要

The structure and ferroelectric properties of Bi_(3.25)La_(0.75)Ti_3O_(12) (BLT) and Bi_(3.25)Nd_(0.75)Ti_3O_(12) (BNT) thin films deposited on (111)Pt/Ti/SiO_2/Si substrates using a metalorganic decomposition (MOD) method were investigated. Both the films were polycrystalline structure with the single bismuth-layered phase. The BNT film showed the (117) random orientation, while the BLT film displayed (00l)-preferential orientation. The BNT film showed a larger remnant polarization (～13.8 μC/cm~2) than the BLT film (～3.5 μC/cm~2), while both films displayed almost the same value of coercive field. The BNT film had the larger dielectric constant and a litter larger dissipation factor than the BLT film. The superior ferroelectricity of the BNT film was mainly attributed to its (117) random orientation. Furthermore, the BNT film displayed good fatigue endurance up to 10~9 switching cycles, indicating it was a useful candidate for integrated device applications.