PHOTOCHEMICAL VAPOR-DEPOSITION OF AL THIN-FILMS ON TI, TIO2, AND PD SURFACES

Al thin films were deposited via photochemical vapor deposition on cat alytic layers of Ti, TiO2, and Pd, using dimethylaluminum hydride, Dep osition was carried out al low gas pressures to induce a surface react ion based on adsorption and subsequent decomposition of adsorbates. Of these three layers Ti was so effective as a catalyst that the Al film s were thermally deposited even at a low substrate temperature of 60 d egrees C with a growth rate of 0.5 nm/min. The UV light generated by a deuterium lamp helped increase the growth rates. On the other hand, A l could be deposited oil TiO2 layers only under irradiation at a subst rate temperature of 120 degrees C. It took several minutes to cover th e TiO2 surface with Al and initiate the Al film's growth. An entirely opposite result was observed for Al deposition on Pd layers. Here, the UV light inhibited the Al growth on the surface, whereas the films we re deposited thermally. X-ray photoelectron spectroscopy showed the fo rmation of a photolytic production of the adsorbate, which acts presum ably as a center that inhibits further Al growth.