In this work latent ion tracks were produced in 0.5 mu m 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 (nu(T)nu(B)). A threshold for track development at about 3 MeV (corresponding to an electronic stopping power of 192 eV/angstrom) was obtained. The velocity ratio then increased with the energy to nu(T)/nu(B) similar or equal to 1.6 at 12.5 MeV (440 eV/angstrom). 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 T and UB. The threshold for track development was again at 3 MeV, and the velocity ratio increased with the energy to nu(T)/nu(B) congruent to 5.5 at 12.5 MeV. The track yield was about 100% for all the energies above the threshold.
Wet and vapor etching of tracks produced in SiO2 by Ti ion irradiation
Bianconi M;Cristiani S
2007
Abstract
In this work latent ion tracks were produced in 0.5 mu m 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 (nu(T)nu(B)). A threshold for track development at about 3 MeV (corresponding to an electronic stopping power of 192 eV/angstrom) was obtained. The velocity ratio then increased with the energy to nu(T)/nu(B) similar or equal to 1.6 at 12.5 MeV (440 eV/angstrom). 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 T and UB. The threshold for track development was again at 3 MeV, and the velocity ratio increased with the energy to nu(T)/nu(B) congruent to 5.5 at 12.5 MeV. The track yield was about 100% for all the energies above the threshold.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
