Ion Mixing of Near-Noble Transition Metal Films on Evaporated and Large-Grained Aluminum Substrates

Abstract

ABSTRACTIon mixing experiments using Xe ions at temperatures ranging from 77K to about 450K were conducted on Al/Ni and Al/Pt couples. Evaporated polycrystalline Al films and large-grained Al crystals were used as substrates. Xenon irradiation of Al/Pt bilayers achieves considerable intermixing and a temperature dependence is observed. Only moderate interfacial mixing with little temperature dependence is observed in Al/Ni bilayers. The mixing efficiency of Al/Ni is consistent with the phenomenological model of thermal spike mixing, and so is the absence of a pronounced temperature dependence below 450K. No significant difference is noted in ion mixing of evaporated and large-grained Al substrates. In contrast to ion mixing, Al/Pt and Al/Ni samples behave similarly upon thermal annealing and form well-defined compounds. The results are also compared with Si/metal systems, where silicides can be formed readily by low temperature thermal annealing as well as by ion mixing of bilayer samples.