NOVEL MODIFICATION METHOD OF SOL-GEL THIN-FILMS - DENSIFICATION OF SILICA-GEL FILMS WITH ELECTRONIC EXCITATION

Significant structural changes in silica gel films with synchrotron ra diation (SR) and energetic He+ ions have been found. Irradiation with photons in the energy range higher than approximately 8 eV and 100-keV He+ ions induce an increase in refractive index and a decrease in thi ckness of silica gel films. Fourier transform infrared absorption spec tra indicate that irradiation with the photons and the ions reduces th e Si-OH content and the average Si-O-Si bridging angle. Electronic exc itation with energetic photons is suggested to induce atomic rearrange ment which causes densification of silica gel. Structural changes with He+ implantation is also tentatively ascribed to an electronic proces s. Electronic processes using SR and light ion implantation are antici pated to offer an alternative route to prepare dense thin films derive d from sol-gel method.