Atomic mixing in thin film systems by swift heavy ions

Because of their sensitivity to the electronic energy loss of swift heavy ions, we have investigated the high energy ion beam mixing of oxide layer systems. In this paper we present a summary of the results and first steps towards interpretation and modelling of the observed phenomena. As was also observed in the case of track formation, mixing was found to occur only if the electronic energy loss exceeds a threshold value. The threshold is determined by the less sensitive material, which is a clear hint that both sides of the interface must have been molten, to enable for effective interdiffusion. This interpretation is supported by the estimated interdiffusion constants which indeed lie in the range known for liquid state diffusion. (C) 2002 Elsevier Science B.V. All rights reserved.