Contact Reactions at Thin Film Aluminium/Transition Metal Interfaces

Abstract

AbstractContact reactions at thin film Al/TM interfaces (TM = W, Cr, Co, Zr and Ta) have been studied by means of cross sectional transmission electron microscopy. In all cases the first phase formed at the interface was the most aluminium-rich compound as given in the correspondent phase diagram: In the case of Al/W, Al/Cr as well as Al/Co growth of Al12W, Al7Cr, and Al9Co2, respectively, with rather smooth, planar morphology has been observed. On the other hand, Al/Zr and Al/Ta contacts exhibit a irregular growth morphology of Al3Zr, and Al3Ta, respectively.In addition, precipitation behaviour of rapidly solidified supersaturated Al(TM) solid solutions upon thermal annealing has been studied, in order to get a better insight on preferred orientation relationships between aluminium and the aluminides as well as on the influence of defects, e.g. grain boundaries.Based on the observed morphologies and orientation relationships a model will be proposed for the different modes of interfacial reactions, i.e. with planar or irregular growth morphology.