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In this work latent ion tracks were produced in 0.5 μm thermal SiO2/Si by Ti ion irradiation. The samples were subsequently etched both in aqueous and in vapor HF solution. As expected, the wet etching process resulted in conically shaped holes, whose superficial diameter increased linearly with the etching time, and was correlated to the track to bulk etching velocity ratio (vT/vB). A threshold for track development at about 3 MeV (corresponding to an electronic stopping power of 192 eV/Å) was obtained. The velocity ratio then increased with the energy to vT/vB ≅ 1.6 at 12.5 MeV (440 eV/Å). For the vapor etching process, cylindrical pores were obtained, with an almost constant diameter of 20–30 nm, until the SiO2/Si interface was reached. Subsequently the pore diameter quickly increased, with a rate much higher than both vT and vB. The threshold for track development was again at 3 MeV, and the velocity ratio …
Publication date: 
1 Apr 2007

F Bergamini, M Bianconi, S Cristiani

Biblio References: 
Volume: 257 Issue: 1-2 Pages: 593-596
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms