Annealing of aluminum thin films deposited on silica

The reaction of aluminum on silica has long been known. We present a morphological study of the small irregular transparent domains which form during the annealing of Al thin films on SiO2 at temperatures in the range 400–600°C. We show that the oxidation of Al and the reduction of SiO2 proceed via irreversible growth of 2-D aggregates, which, in some regimes, are DLA-fractals. The morphological approach, which is complementary to the purely thermodynamic studies done so far, gives information on the chemical process.