An Arxps Investigation of the Initial Growth of Aluminum Films on the (0001) Face of Sapphire.

The (0001) face of α-Al2O3 and the initial growth of ultra-thin aluminum, films deposited on this surface were studied by a combination of low energy electron diffraction, angle resolved x-ray photoelectron spectroscopy and thermal desorption techniques. At high temperatures, the (0001) face of α-Al2O3 reconstructs to form a (√31×√31)R±9° structure which remains stable at lower temperatures, as evidenced by IEED. ARXPS shows that the annealed sanple retains its bulk composition up to the solid-vacuum interface. Thin Al films were deposited on the above surface by in situ evaporation. ARXPS results indicate a uniform growth of the initial monolayer of aluminum. Further growth (<3 A°) deviated fr the layer by layer adsorption mechanism.