Effect of SiOH and SiCl on ArF-excimer laser-induced absorption in soot-remelted silica

Characteristics of ArF-excimer laser-induced absorption in various types of fused silica synthesized by the vapor-phase axial deposition-soot remelting method were investigated. Fused silica containing 2-6 x 10(18) cm(-3) of OH and no Cl shows an absorption band at 5.8 eV ascribed to the E' center (=Si .) and an absorption band at 4.8 eV ascribed to oxygen related centers. A sample containing about 3 x 10(19) cm(-3) of Cl and no OH shows only the 5.8 eV band. An OH- and Cl-free silica had a preexisting absorption band at 5.0 eV ascribed to an oxygen deficient center (ODC; = Si ... Si =) and a weak band at 5.8 eV; the 5.0 eV band changed into a 5.8 eV band by irradiating it with the ArF laser. These phenomena can be interpreted as follows: typical silica glasses are considerably deformed from the ideal network and terminal groups such as Si-OH and Si-Cl reduce some amount of highly strained bonds in the glass network. In the sample containing a considerable amount of Cl and no OH, Si-Cl could be the major precursor of the E' center because only a weak 5.8 eV band is observed. In silica containing a relatively small amount of OH and no Cl, bond breakage is the major process by which laser induced defects are produced. (C) 1997 American Institute of Physics.