Experimental evidence for Frenkel defect formation in amorphous SiO2 by electronic excitation

Concentrations of defects in amorphous SiO2 created by implantation of 10 MeV protons were examined. The depth profile of Si-Si bonds, E' centers, or peroxy radicals (PORs) was close to that of electronic energy loss. Interstitial O-2 molecules were identified and their concentration was larger than that of PORs. The total concentration of the Si-Si bonds and E' centers was comparable to that of the interstitial O-2 and PORs. These results provide experimental evidence that Frenkel defect formation of an oxygen occurs in amorphous SiO2 by dense electronic excitation. The efficiency of the Frenkel defect formation was estimated as similar to 5 X 10(-7) eV(-1).