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Structure of latent tracks created by swift heavy-ion bombardment of amorphous SiO 2

2000; American Physical Society; Volume: 62; Issue: 6 Linguagem: Inglês

10.1103/physrevb.62.3689

1095-3795

Kunio Awazu, Satoshi Ishii, Kunihiro Shima, S. Roorda, J. L. Brebner,

Diamond and Carbon-based Materials Research

The defect structure of ion irradiation damage localized in latent tracks in amorphous ${\mathrm{SiO}}_{2}$ and their role in the chemical etch rate of such tracks has been studied. A variety of light and heavy ions were used with energies ranging from 4 to 127 MeV. It was found that the frequency of the infrared absorption associated with the asymmetric stretch vibration of Si-O was significantly reduced following swift heavy-ion bombardment and that the shift correlated with the enhancement of the etching rate. In contrast, no correlation between the etching rate and either the ${E}^{\ensuremath{'}}$ center or the oxygen deficient center was observed. The IR peak shift has been related to the transition of ordinal six rings of ${\mathrm{SiO}}_{4}$ tetrahedra to planar three- and four-member rings, which were generated in the latent track due to the flash heating and quenching by bombardment. We propose that large numbers of planar three- and four-member rings in the latent track are responsible for the fast chemical etching rate.