DEFECT PAIR CREATION THROUGH ULTRAVIOLET-RADIATION IN DENSE, AMORPHOUS SIO2

Defect creation in 24% densified, high-OH-concentration amorphous SiO2 has been studied using 248-nm excimer laser radiation. Combining laser and -ray radiation data, we find correlated growth of oxygen-vacancy and nonbridging oxygen-hole-center defects over a range of concentration from 5×1015 to 5×1017 cm-3. Oxygen-hole centers are created at least 100 times more efficiently in densified, high-OH-concentration SiO2 than in undensified, high-OH-concentration SiO2 for the same 248-nm-radiation dose. It is argued that strained bond cleavage is the dominant mechanism of defect creation by energetic photons in metastably densified oxides. The primary oxygen-vacancy-center creation mechanism by ultraviolet radiation in undensified, high-OH-concentration SiO2 appears to be network-atom-displacement related. © 1990 The American Physical Society.