INFLUENCE OF OXYGEN IMPURITIES ON ION BEAM INDUCED INTERDIFFUSION IN THIN Au-Al MULTILAYERS DEPOSITED ON DIFFERENT SUBSTRATES

Abstract

Au-Al interdiffusion processes in thin layers deposited on various substrates were investigated with RBS during high current ion irradiation. The atomic movements were identified simultaneously (in-situ RBS) with a depth resolution of a few nanometers. It was observed that heating of the specimens due to ion irradiation was the most evident mechanism inducing atom transport. After only 8 min of irradiation with 300 nA 2.0 MeV 4 He + ions (beam spot diameter 0.5 mm), two Au-Al layers (total thickness 600 nm) deposited on glassy carbon or gold were found to be fully interdiffused. In contrast to that, no significant interdiffusion was measured for the same systems deposited on wafer silicon and polished aluminium substrates. To understand this behaviour, depth distributions of oxygen impurities were measured using enhanced elastic backscattering spectroscopy (σ ≈ 102 σ R with 7.6 MeV 4 He ions.