XPS studies on intermetallic phases formed in Al-Ni and Al-Mn thin films

Thin films of AlNi and AlMn alloys were prepared by high-temperature successive vapour deposition (HTSVD). In the case of AlNi a pronounced shift (∼0.5 eV) of the Ni Auger parameter [combined Ni 2p binding energy (BE) and Ni L3 VV kinetic energy (KE) values] to lower values can be detected for the Al3Ni compound, the structure of which was determined by x-ray diffraction. In the AlMn system a quasi-crystalline Al4Mn phase was formed and its structure was determined by selected area electron diffraction as well as by TEM and cross-sectional TEM. XPS measurements show that for this AlMn phase only a small peak shift (∼0.3 eV) of the Mn 2p core level can be related to the compound formation as compared to the pure metallic state of the components. The same shift to lower values was also obtained for the Auger parameter (Mn 2p BE + Mn L3M23M23). The small peak observed by others at 2.4 eV higher than the Al 2p BE is unambiguously related to the oxygen content in our samples. On the basis of the results we can conclude that the observed core level and Auger line shifts; the small linewidths and especially the Auger parameter shift to lower values are all indicative of the formation of intermetallic compounds in these systems.