Abstract :
The ultra-soft X-ray emission spectra were taken from surfaces of bulk silica glass and silica glass films exposed to an
argon excimer laser ls126 nm.and compared with the spectra taken from the virgin surfaces. The precipitation of
crystalline silicon is found to take place in thin surface layers of the irradiated bulk silica glass and 15 nm film. An
estimation of concentration of crystalline silicon precipitation with the depth is given on the basis of the measurements of Si
L2,3 X-ray emission spectra obtained at different accelerating voltages of the electron beam on the X-ray tube. Based upon
the precipitation conditions for these samples, we discuss the crystalline silicon precipitation mechanism: the electronic
excitation induces the bond-breaking between Si and O atoms, although there is a critical density of photons for the
bond-breaking and temperature rise enhances the crystalline silicon precipitation. q1998 Elsevier Science B.V.
