Photosensitive gel films prepared by the chemical modification and their application to surface-relief gratings

A novel technique has been developed to fabricate surface-relief gratings u sing photosensitive gel films. Gel films which were derived from metal-alko xides chemically modified with P-diketones were photosensitive owing to rem aining chelate rings; the W-irradiation of these gel films substantially de creased their solubility in acidic aqueous solutions or organic solvents. L eaching of the gel films after UV-irradiation through a mask and subsequent heat-treatment gave negative patterns of the mask used. Fine-patterns of P LZT films, as well as Al2O3, ZrO2, and TiO2 films, were successfully formed by the above process. Utilizing this process, surface-relief gratings were fabricated on silica glass and Si substrates by the irradiation of the mod ified gel films with a XeF excimer laser through a phase mask. Very uniform diffraction gratings with a pitch of about 1.0 mu m were produced for Al2O 3, ZrO2, and TiO2 films, along with PLZT films. The morphology and diffract ion efficiency of the gratings obtained were examined in terms of fabricati on conditions. (C) 1999 Elsevier Science S.A. All rights reserved.