Electrochemical deposition of barium titanate thin films on TiN/Si substrates
Abstract Barium titanate (BaTiO 3 ) films were synthesized on TiN-coated Si substrates by electrochemically anodic oxidation in mixed alkaline electrolytes of 0.5 M Ba(CH 3 COO) 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 BaTiO 3 films were successfully prepared on TiN-coated substrates at the reaction voltages above 2 V. Field-emission scanning electron microscopy revealed that the obtained BaTiO 3 films possessed uniformly distributed spherical-particulate surface morphology with a nanolayered feature. The thickness of BaTiO 3 could reach about 4 μm after electrochemical oxidation with the voltage of 60 V. The growth rate of BaTiO 3 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 BaTiO 3 films over the substrates.