Concentrations of defects in amorphous ${\mathrm{SiO}}_2$ created by implantation of 10 MeV protons were examined. The depth profile of Si-Si bonds, $E^{\prime }$ centers, or peroxy radicals (PORs) was close to that of electronic energy loss. Interstitial ${\mathrm{O}}_2$ molecules were identified and their concentration was larger than that of PORs. The total concentration of the Si-Si bonds and $E^{\prime }$ centers was comparable to that of the interstitial ${\mathrm{O}}_2$ and PORs. These results provide experimental evidence that Frenkel defect formation of an oxygen occurs in amorphous ${\mathrm{SiO}}_2$ by dense electronic excitation. The efficiency of the Frenkel defect formation was estimated as $\sim 5\times {10}^{-7\mathrm{}}{\mathrm{eV}}^{-1\mathrm{}}$.

• Received 15 August 1997

DOI:https://doi.org/10.1103/PhysRevLett.80.317