Sol-gel processing of oriented SrTiO₃ thin films

Sol-gel processing was employed to fabricate multilayered SrTiO₃ thin films onto fused silica, Si (100) and SrTiO₃ (110) substrates. A Sr-Ti alkoxide precursor solution, chemically modified with diisopropanolamine, was hydrolyzed and spin-coated onto these substrates. These films were annealed at 300 °C and then heated to 650 °C for 1 h in air, which resulted in the formation of phase pure crystalline SrTiO₃. X-ray diffraction analysis indicated that partially oriented films were deposited onto fused silica and Si (100), while highly oriented film was formed on SrTiO₃ (110). A typical microstructure of the film deposited on SrTiO₃ (110) and heated at 650 °C for 1 h showed the presence of submicrometer grains on the order of 0.05 to 0.1 μm. The thickness of a single coating measured from the cross section of the SEM micrograph was about 0.1 to 0.2 μm.