Arsenic beam induced mixing in Ta/Pd thin films

In this paper we present a study of atomic mixing in Ta/Pd bilayers deposited on silicon, induced by As+ ion implantation. The films were deposited by dc sputtering to thicknesses of 60 nm (Pd) and 50 nm (Ta) on n-(111)Si wafers. After deposition the samples were implanted with As+ ions at 250 keV and 450 keV, to doses from 1 x 1015 ions cm-2 to 1 x 1016 ions cm-2, at room temperature (RT). Thermal treatments of samples were performed in vacuum (1 x 10-5 mbar) at 400oC and at 600oC, for 20 min. Structural changes were analysed by Rutherford backscattering spectroscopy (RBS), X-ray diffraction (XRD) and scanning electron microscopy (SEM). We have studied the effects of the ion ranges and doses on the reactions in films, and also the effects of additional thermal treatments. The results indicate a dependence of the mixing processes on the film thickness to the ion range ratio (d/Rp). (author)