Contact resistivity reduction through interfacial layer doping in metal-interfacial layer-semiconductor contacts

Metal-induced-gap-states model for Fermi-level pinning in metal-semiconductor contacts has been extended to metal-interfacial layer (IL)-semiconductor (MIS) contacts using a physics-based approach. Contact resistivity simulations evaluating various ILs on n-Ge indicate the possibility of forming low resistance contacts using TiO2, ZnO, and Sn-doped In2O3 (ITO) layers. Doping of the IL is proposed as an additional knob for lowering MIS contact resistance. This is demonstrated through simulations and experimentally verified with circular-transfer length method and diode measurements on Ti/n(+)-ZnO/n-Ge and Ti/ITO/n-Ge MIS contacts. (C) 2013 AIP Publishing LLC.