Ion-beam-induced SbSi mixing

Abstract

Thin 15 nm bilayers of antimony on silicon, or a thin 10 Å antimony marker layer buried in a matrix of silicon, were irradiated with 10 keV Ar + at room temperature with fluences in the range from 5 × 10 14 to 3 × 10 16 ions cm -2 Sputtering of the antimony film during ion irradiation was compensated for by simultaneous controlled deposition (dynamic mixing). 2 MeV helium backscattering was used to study the resulting films and to examine the interfacial changes occuring as a result of ion beam mixing. The amount of mixing was found to be proportional to ϕ 1 2 . The mixing efficiency was found to be in reasonable agreement with previously reported data using 200–300 keV bombarding ions but it was an order of magnitude higher than that obtained using the linear cascade mixing conditions of Sigmund and Gras-Marti. The effect of film thickness on mixing was investigated by varying the antimony film thickness in the range 50–200 Å and the results were compared with those obtained using a computer simulation model based on the MARLOWE code and using a Thomas-Fermi potential with a screening length suggested by Firsov. There appears to be good agreement between the simulated and the experimentally obtained data.