Low current MeV Au2+ ion-induced amorphization in silicon: Rutherford backscattering spectrometry and transmission electron microscopy study

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Vol. 207; no. 3; pp. 291 - 295
• Main Authors: Kamila, J., Satpati, B., Goswami, D.K., Rundhe, M., Dev, B.N., Satyam, P.V.
• Format: Journal Article
• Language: English
• Published: 01.07.2003
• ISSN: 0168-583X
• DOI: 10.1016/S0168-583X(03)00459-2

The amorphization due to MeV Au2+ ion implantation in Si(111) has been studied using Rutherford backscattering spectrometry /channeling (RBS/C) and transmission electron microscopy (TEM) methods. 1.5 MeV Au2+ ions were implanted into Si(111) substrates at various fluences at low currents (0.02-0.04 *mAcm-2) while the samples were kept at room temperature. The RBS/C results for as-implanted specimen shows the onset fluence for amorphization to be ~5x1013 ionscm-2 which is much lower than the fluence reported earlier. Selected area diffraction (TEM) for a sample implanted at a of 1x1014 ionscm-2 confirms the occurrence of the amorphization. Earlier, amorphization studies by Alford and Theodore, using 2.4 MeV gold ions in silicon (100) reported a threshold fluence of 1.8x1015 ionscm-2 for amorphization when the implantation was carried out at higher currents (0.2-5 *mAcm-2) [J. Appl. Phys. 76 (1994) 7265]. The nuclear energy loss (Sn) for 1.5 MeV gold ions in silicon is ~13% greater than the value for 2.4 MeV and cannot be the sole reason for lower threshold fluence for the amorphization. The amorphization at a relatively lower fluence for the low current implantations could be possible due to reduction in the dynamical annealing effects.