Solid state reactions in Al–Cu–Fe thin film systems

This work is an investigation on the phase formation in Al–Cu–Fe thin film systems. This investigation was carried out on four samples with different Al/Cu/Fe thickness ratios. The samples were prepared by sputtering at room temperature and characterised using in-situ resistivity measurements, and in-situ X-Ray Diffraction (XRD) measurements from room temperature up to 600 °C. The sequence of phase formation was evidenced for all the samples studied in this work. Whatever the composition, the first reaction occurs at the Al/Cu interface at around 200 °C and leads to the formation of Al2Cu. The nature of the following phases depends on the Al/Cu/Fe thickness ratios. Since at the end of the heat treatment, the sample has reached its equilibrium state, this work also brings new information on the Al–Cu–Fe ternary phase diagram. Resistivity values at room temperature of the ternary single phase materials, α-Al23CuFe4 and ω-Al7Cu2Fe, are reported for the first time.