SOL-GEL FABRICATION OF EPITAXIAL AND ORIENTED TIO2 THIN-FILMS

Thin films of titania have been prepared by spin coating on fused silica, Si(100), and rutile(110), starting with a sol-gel process. The alkoxide solution was chelated with diisopropanolamine, and the resulting precursor solution was hydrolyzed prior to coating. Oriented rutile films were obtained on fused silica and Si(100), while epitaxially oriented film was formed on rutile(110). X-ray diffraction results indicated that the as-deposited films transformed to rutile via anatase with increasing temperature. The phase transformation temperature was found to be dependent on the substrate, and it was in general higher on the substrates than that observed for the gel powder. Microstructural studies revealed that these films consisted of finely dispersed grains of 0.05 to 0.15-mu-m in size.