Radiation Effects Of Vacuum Ultraviolet Laser Photons on Silicon Dioxide

Abstract

AbstractThe argon excimer laser provides 9.8-eV photons that readily surmount the electronic bandgap energy of SiO2 (∼9.0 eV), directly generating excitons in a single-photon absorption process. We have shown by Si L2,3 (Si 3s→2p) X-ray emission spectroscopy, Si 2p X-ray photoelectron spectroscopy and Raman spectroscopy that this absorption process is responsible for silicon precipitation in the silica. The X-ray emission studies further show that the silicon precipitates are crystalline, forming in highest concentration in 120–230 nm layer beneath the laserirradiated surface. Silicon precipitation was not observed on samples irradiated with 146-nm krypton excimer radiation due to a smaller 8.5-eV photon energy that is below the silica bandgap.