F-doped and H2-impregnated synthetic SiO2 glasses for 157 nm optics

Optical transmission change and point defect formation by irradiation with F-2 excimer laser light (similar to 10 mJ/cm(2)/pulse x 3.6 x 10(5) pulses, lambda = 157 nm) were examined for four types of synthetic SiO2 glasses: wet (OH content: 1.7 x 10(19) cm(-3)), dry (OH content: <1 x 10(16) cm(-3)), F-doped (F content: 2.2 x 10(20)-4.2 x 10(20) cm(-3), OH content: <1 x 10(16) cm(-3)), and H-2-impregnated (OH content; 1.9 x 10(18) cm(-3), H-2 content; 1 x 10(18) cm(-3)) SiO2 glasses.; Intense optical absorption bands peaking at 4.8 and 5.8 eV, which are attributed to nonbridging oxygen hole center and E' center, respectively, and a shoulder at similar to 7 eV were induced in the wet and dry specimens after the irradiation. On the other hand, the intensities of absorption bands induced in the F-doped and H-2-impregnated specimens were smaller by an order of magnitude than those in other specimens. The internal (reflection-corrected) transmittance at the wavelength of 157 nm for 5 mm thick samples after the irradiation was 87% for the F-doped, 82% for the H-2-impregnated, 14% for the wet, and 2.4% for the dry silica glasses. The present results show that F doping or H-2 impregnation is an effective way to improve resistance of SiO2 glasses to F-2 laser damage. (C) 1999 American Vacuum Society. [S0734-211X(99)09606-7].