Direct contact of indium tin oxide layer to Al(Ni) alloy electrodes for a-Si:H thin film transistors: Effects of Ni alloying on interfacial oxide growth and contact resistance

Sputtering of indium tin oxide (ITO) on pure Al substrate produces an Al2O3 layer at the interface, leading to Schottky contact characteristics. A very small amount of Ni (2at.% Ni) added to Al drastically reduces the contact resistance of an ITO/Al(Ni) alloy electrode to approximately 4.3×10-4Ω-cm2, with a low electrical resistivity of~3 μΩ-cm, demonstrating the feasibility of using ITO/Al(Ni) alloy structures as electrodes for a-Si:H thin film transistors. The mechanism for initial interfacial oxidation occurring during sputtering of ITO on the surface of Al(Ni) and subsequent annealing at 320°C was proposed to reveal the role of Ni during the sputtering and annealing processes. •Indium tin oxide (ITO)/Al(Ni) alloy contacts were fabricated.•Contact resistance of ITO/Al(Ni) alloy varied with Ni content.•Mechanism for initial interfacial oxidation during sputtering of ITO was proposed.