Mechanical stress effect on leakage current in Bi3.25La0.75Ti3O12 thin films

Bi3.25La0.75Ti3O12 (BLT) ferroelectric thin films were prepared on Pt/Ti/SiO2/Si substrates by metalorganic decomposition method. Mechanical stress effect on leakage current was investigated. The results demonstrate that the leakage current increases with increasing electric field. Under mechanical tensile or compressive stress, the increase trend of the leakage current with electric field shows negligible change in low field region (below 75 kV/cm), while that gets weakened in high field region (above 75 kV/cm) compared with that at free state (zero stress). At a certain electric field (above 75 kV/cm), the leakage current decreases with increasing tensile or compressive stress. The effect of domain reorientation induced by stress combined with the contribution from charge injected into films is found to be reasonable for the explanation of the leakage current in BLT thin films under different stress.