Schottky-Ohmic transition in metal-all-around electrical contacts to silicon nanowires

In this paper, systematic study on electrical contacts to silicon nanowires (SiNWs) is performed using a developed Schottky barrier simulator. At room temperature, the SiNW-metal contact is always characterized by Schottky behaviors, with the barrier height exhibiting a minimum at a diameter of about 4 nm. At ultralow temperature of 138 K, a Schottky-Ohmic transition is found in SiNW, which originates from the limited extent of the depletion region in SiNW as a result of its small geometrical dimension. The generality of diameter dependent barrier heights for different material configurations, impacts of doping in SiNW, and interfacial oxide layer between the metal and SiNW is also studied to understand the influence of the SiNW size on the contact properties including Schottky barrier height, band profile, and specific contact resistance. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3117490]