In-situ preparation of polycrystalline BaTiO3 thin films on silicon by hydrothermal method

Insulating cubic BaTiO3(c-BT) polycrystalline thin films were synthesized on titanium covered silicon substrates using a novel low temperature technique called hydrothermal method. The films were hydrothermally formed by submerging the substrate in a 0.5M Ba(OH)(2) aqueous solution sealed inside an autoclave, heating to 160 degrees C with saturated vapor pressure around 0.8MPa and holding for various periods ranging from 1 to 9 hours. The surface of as-treated samples was dense, smooth pinhole-free with high homogeneity. Scanning electron microscopic (SEM) morphology showed the 6-hour-prepared films were composed of submicrocrystallines with grain Size varied from 100 to 300nm in diameter. The films were characterized by X-ray diffraction (XRD), SEM, cross-sectional transmission electron microscopy (XTEM), Auger electron spectroscopy (AES) and Rutherford backscattering spectroscopy(RBS) analyses. The experimental results proved that hydrothermal method will become a valuable approach for fabricating perovskite oxide films which is of great significance.