Dielectric and optical properties of BaTiO3 thin films prepared by low-temperature process

Barium titanate (BaTiO3) thin films have been prepared by low temperature processing on Pt/Ti/SiO2/Si substrates using sol-gel-hydrothermal (SGHT) technique, which combined the conventional sol-gel process and hydrothermal method. X-ray diffraction analysis showed that the barium titanate thin films are polycrystalline. As-reacted barium titanate films grown on Pt(111)/Ti/SiO2/Si(100) substrates had a dielectric constant (epsilon) and loss tangent (tan delta) of 80 and 0.05 at 1 MHz, respectively. The optical constants including refractive index n, extinction coefficient k, and absorption coefficient alpha of the barium titanate thin films in the wavelength range of 2.5-12.6 mu m were obtained by infrared spectroscopic ellipsometry.