CHARACTERIZATION OF MIXED ZINC-OXIDIZED ZINC THIN-FILMS DEPOSITED BY A COLD REMOTE NITROGEN PLASMA

A method for the deposition of a zinc-containing film on aluminium and polypropylene substrates by a cold remote nitrogen plasma (CRNP) was described. The reactivity of the CRNP was first used to clean the substrate which had to be metallized; when the substrate was a polymer, this step was also used to increase its wettability. The reactivity of the CRNP was then used to decompose diethylzinc vapour in order to deposit, at ambient temperature, a zinc-containing film with a blue-grey metallic appearance. XPS analyses were performed after transfer to ambient air during about 10 min. An Ar+ etching procedure was then used to progressively investigate the inner layers. The evolution of the Zn Auger LMM transition and of the O1s, C1a and N1s photoelectron peaks were studied versus the Ar+ etching duration. Under a contamination layer, the amounts of C and N relative to Zn in the coating film were very low while oxidized zinc species have been detected in the film. Oxidation of the Zn deposit may occur either during the process itself or during air exposure before XPS analyses considering the porosity of the film. The nature of the interface with the substrate appears different: with the aluminium substrate, the deposited film was a Zn-ZnO-Zn(OH)(2) mixture with a zinc rate equal to 55%. With the polypropylene substrate, Zn(OH)(2) appeared only on the outer layer. Inside it was a Zn-ZnO mixture.