QUASI-CRYSTALLINE STRUCTURE FORMATION IN THIN-FILMS

Experimental techniques used for preparing quasi-crystalline (QC) thin films are reviewed. Results of experiments in which the QC phase formation was produced by high temperature (575 K) successive deposition (HTSD) of aluminium and a transition metal are discussed in detail. It is shown that HTSD-prepared thin of QC phase formation. A model consisting of nucleation, growth and coalescence of QC grains as well as perpendicular growth of the continuous film is proposed for the description of QC film growth. Auger depth profiling and energy-dispersive X-ray analysis of cross-sectional transmission electron microscopy samples of the Al/QC layer system proved the homogeneity of a thick (approximately-0.5-mu-m) QC film and gave a composition of 80 at.% Al-20 at.% Mn for the QC phase. It has been determined that the reaction producing the QC phase takes place at the free surface of the QC phase in the case of HTSD, and aluminium is transported through the QC layer to the reaction sites. The formation of voids in the host aluminium films indicates that there exist specific sites in these films, possibly resulting from defects, which are the sources of aluminium diffusion.