Low leakage BiFeO3 thin films fabricated by chemical solution deposition

BiFeO3 (BFO) films were fabricated by spin-coating precursor solution on Pt/Ti/SiO2/Si(100) substrates through chemical solution deposition (CSD) technique. A pure perovskite phase was formed at annealing temperatures as low as 350 degrees C for 10 min. The leakage current density decreased with annealing temperature until 500-550 C,degrees and then increased again at 600 degrees C. The lowest leakage current density obtained was about 10(-6) A/cm(2) at 100 kV/cm for the 500 degrees C-annealed BFO film. The leakage current was found to be closely related to grain size and grain size distribution, indicating that grain boundary-related mechanisms dominate conduction. The dielectric constant increased with increasing annealing temperature from 90 to 120. The polarization-electric field curves could be obtained even in BFO films annealed at such low temperatures as 350 degrees C. The remnant polarization remained relatively unchanged with annealing temperature, which was about 30 mu C/cm(2), and the coercive field had a value close to 80 kV/cm. (c) 2005 The Electrochemical Society.