EXTRINSIC-DEFECT AND INTRINSIC-DEFECT CREATION IN AMORPHOUS SIO2

We have studied the creation efficiency of various intrinsic and extrinsic defects in high-[OH] amorphous silica subjected to the ultraviolet emission from an O2 plasma or Co60 -ray radiation. Both oxygen-vacancy- and nitrogen-related defects are observed following -ray irradiation or ultraviolet exposure. The wavelength range responsible for defect creation is estimated to be 200300 nm (4Ephoton5.9 eV). The ultraviolet power output of the plasma estimated by comparing defect yields with those from a Hg lamp (=185 and 254 nm) suggests 200P900 mW cm-2 for a plasma power density 300 mW cm-3. Nonbridging oxygen-hole centers and hydrogen-related defect centers as well as methyl radical (CH3.) defects are observed after -ray irradiation but not after ultraviolet exposure. The efficiency of creation of the various defects is material dependent. © 1990 The American Physical Society.