Real-time RBS of solid-state reaction in thin films

Selected examples of real-time RES are shown to underline the strengths of the technique. Due to the simultaneous depth and compositional profiling capabilities of RES it is possible in combination with a linearly ramped heat treatment, to determine both the pre-exponential factor and the activation energy of phase formation from a single sample. Other in situ, real-time techniques also use linearly ramped temperature anneals but require several different temperature ramps to obtain the same parameters. In inert marker experiments the movement of a thin, inert layer is used to determine the atomic transport during growth. The example shown highlights the advantages of the real-time RES technique where slight movements of the marker layer are significant. Linear reaction kinetics is shown for CrSi2 formation. Two linear regimes were found. The second regime coincided with unintentional oxidation of the Cr surface. An added advantage of kinetic analysis by real-time RES is the fact that in those cases where sample preparation is difficult and at times irreproducible, e.g. due to experimental details, the fact that the sample kinetics can be measured from a single sample provide far better results. This is illustrated by considering growth kinetics of Ni-Si samples, where the Si had been intentionally doped with oxygen. (C) 2000 Elsevier Science B.V. All rights reserved.