FORMATION OF AN ACTIVE ELECTRONIC BARRIER AT AL SEMICONDUCTOR INTERFACES - A NOVEL-APPROACH IN CORROSION PREVENTION

Aluminum surfaces exhibit improved corrosion protection when coated with suitable semiconductor/insulator thin films. These coatings, generally realized in metal-semiconductor (MS) or metal-insulator-semiconductor (MIS) structural configurations, lead to an interfacial electric field that acts as an effective built-in electronic barrier. Anodic polarization data on samples fabricated in both MS left bracket e. g. , Al-indium tin oxide (ITO) right bracket and MIS(e. g. , Al-SiO//2-ITO) configurations have demonstrated the protective nature of the barrier. The electronic barrier heights increase with the presence of a thin SiO//2 layer at the metal/semiconductor interface and the energy gap of ITO, which depends on the indium content. A comparison of these results with data on plasma-deposited Al-Si//3N//4 samples is also presented.