Electrochemical deposition of barium titanate thin films on TiN/Si substrates

Barium titanate (BaTiO3) films were synthesized on TiN-coated Si substrates by electrochemically anodic oxidation in mixed alkaline electrolytes of 0.5 M Ba(CH3COO)2 and 2 M NaOH. A potentiostatic mode was conducted to make the films with the voltages ranging from 2 to 60 V at 70 °C for only 1 min. X-ray diffraction results show that cubic BaTiO3 films were successfully prepared on TiN-coated substrates at the reaction voltages above 2 V. Field-emission scanning electron microscopy revealed that the obtained BaTiO3 films possessed uniformly distributed spherical-particulate surface morphology with a nanolayered feature. The thickness of BaTiO3 could reach about 4 μm after electrochemical oxidation with the voltage of 60 V. The growth rate of BaTiO3 films synthesized by the electrochemical oxidation was much faster than that of the films prepared by the previously reported hydrothermal and hydrothermal–galvanic couple methods where only a single layer was produced. Potentiodynamic polarization reveals that the corrosion resistance of TiN-coated substrates was greatly improved by electrochemical deposition of the dense and thick BaTiO3 films over the substrates.