Anomalous diffusion of Mo implanted into aluminium

Mo ions are implanted into aluminium with a high ion flux and high dose at elevated temperatures of 300 degree C, 400 degree C and 500 degree C. X-ray diffraction spectra show that the Al12 Mo phases are formed. Rutherford backscattering spectroscopy indicates that a profile of Mo appears in Al around the depth of 550 nm and with an atomic concentration of ∼7%, when Mo is implanted to the dose of 3 x 1017/cm2 with an ion flux of 45 μA/cm2 (400 degree C). If the dose increases to 1 x 1018/cm2 at the same ion flux, the penetration of Mo ions in Al can reach a depth of 2μm, which is greater than the ion project range Rp (52.5 nm) . The results show that anomalous diffusion takes place. Owing to the intense atom collision cascades, the diffusion coefficient increases greatly with the increase of the ion flux and dose. The Mo diffusion coefficients in Al are calculated . The Mo retained dose in Al increases obviously with the increase of the ion flux