Characterization of lanthanum-doped bismuth titanate thin films prepared by polymeric precursor method

Lanthanum-modified bismuth titanate, Bi 4− x La x Ti 3O 12 (BLT), with x ranging from 0 to 0.75 was grown on Pt/Ti/SiO 2/Si substrates using a polymeric precursor solution and spin-coating method. The dielectric constant of highly doped bismuth titanate was equal to 148 while dielectric losses remained low (tan δ=0.0018), and the films showed well-saturated polarization-electric field curves (2 P r=40.6 μC/cm 2 and V c=0.99 V). The leakage current densities improve for the lanthanum-doped system. For five-layered BLT films with x=0.75, a charge storage density of 35 fC/μm 2 and a thickness of 320 nm were found.