Damage of alumina films by medium energy hydrogen and helium ions

Bailey, Paul, Noakes, T.C.Q., Liu, Y., Alexander, M.R., Koroleva, E.V., Skeldon, P., Thompson, G.E., Habazaki, H. and Shimizu, K. (2002) Damage of alumina films by medium energy hydrogen and helium ions. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 197 (3-4). pp. 265-270. ISSN 0168-583X

Abstract

Following previous observations of detachment of amorphous, anodic alumina films from aluminium by 100 keV H+ ions, further experiments have been carried out using H+, D+, 3He+ and 4He+ ions, at energies in the range of 0.5–270 keV, to irradiate anodized aluminium with oxides of thickness from 30 to 500 nm. Surface damage was investigated by field-emission-gun scanning electron microscopy and transmission electron microscopy. Detachment of the oxide, which takes place close to, or at, the metal/oxide interface, occurred only following irradiation by H+ and D+ ions, with the ions being stopped in the metal rather than the oxide. The threshold fluence for initiation of detachment is approximately 3×1015 ions cm−2. No detachment was detected following irradiations by 3He+ and 4He+ ions with fluences up to 5×1016 ions cm−2 and ranges similar to those of H+ and D+ ions, although vacancy production is much greater for helium ions. These findings indicate that detachment is associated with accumulation of hydrogen species in the vicinity of the metal/oxide interface, rather than condensation of vacancies. Such behaviour is consistent with the expected mobility of hydrogen, but not of helium, in aluminium near room temperature

Item control for Repository Staff only: