Photolysis of organically modified gel films and its application to the fine-patterning of oxide thin films

Abstract

The fine-patterning process is very important for the application of sol-gel derived thin films to optical and electronic devices. In the present study, a new technique for the patterning of oxide thin films has been developed. Gel films obtained from metal-alkoxides chemically modified with (beta) -diketones have optical absorption bands in the UV-range characteristic of the (pi) -(pi) * transition in chelate bonds. The irradiation of UV-light corresponding to this transition dissociated the chelate bonds and simultaneously decreased the solubility of the gel films in acidic solutions or alcohols. These findings are indicative of the occurrence of some structural changes in the gel films. The change in solubility of organically modified gel films by the UV-irradiation has been applied to the fine-patterning process; the gel films were irradiated with UV-light and leached in appropriate solutions, followed by the heat-treatment. The present process enables us to make fine-patterns of ZrO<SUB>2</SUB> and TiO<SUB>2</SUB> films on a variety of substrates.