Fluorine Penetration into Amorphous SiO2 Glass at SF6 Atmosphere Using Q-Switched Nd:YAG and Excimer Laser Irradiations

At low pressures up to 0.1 mbar, the evidence of simultaneous SF6 gas decomposition and the morphology alteration on amorphous SiO2 glass have been investigated using various laser irradiations at typical wavelengths, i.e., ultraviolet (UV; 193 nm), visible (532 nm), and near infrared (NIR; 1064 nm). The instrumental micro-analysis of the surface were carried out by a number of instruments such as laser breakdown spectroscopy (LIBS), scanning electron microscopy (SEM), Rutherford back scattered spectroscopy (RBS), wavelength dispersive X-ray (WDX) mapping, energy dispersive X-ray (EDX) microanalysis and photo-spectrometry accordingly. It was shown that the excimer laser at shorter wavelengths induces microstructuring on glass mainly due to the surface UV photoablation and the subsequent collisional SF6 decomposition. Conversely, at the longer wavelengths such as the fundamental and second harmonic generation of a Q-switched Nd:YAG laser, the treatment of the target is done based on the micro-plasma induced ablation and the following electron-impact SF6 decomposition. (C) 2010 The Japan Society of Applied Physics