Crystallization and microstructure development of sol-gel derived titaniumdioxide thin films with single and multiple layers

Sol-gel TiO2 thin films were fabricated at 650 degrees C using sol that was derived from the Ti((OPr)-Pr-i)(4)-diethanolamine-H2O-(PrOH)-Pr-i system. Repeated deposition and rapid heating resulted in columnar grains, whereas slow heating-at a rate of 10 degrees-20 degrees C/min-caused equiaxed grain s to form. Slow heating caused the film to crystallize as anatase. The anat ase-to-rutile ratio of the rapidly heated film increased with increased dep osition thickness and repeated depositions. The tendency of the thicker fil m to crystallize as rutile during rapid heating was attributed to the rapid grain growth of fine anatase grains.