Improved ohmic contacts for SiC nanowire devices with nickel-silicide

Abstract

The effect of annealing temperature has been investigated to obtain a low ohmic contact for silicon carbide nanowire field-effect transistor (SiC NW FET). Fabrication of two types of SiC NW FET has been studied using cylinder and needle shapes of SiC NW. The experimental results show that an annealing temperature of 650 °C leads to the lowest ohmic contact resistance on SiC NW FET. It is believed that the Ni silicide phases formed on SiC NWs make low resistance ohmic contacts. Ni silicide phases begin to intrude into the SiC NW channel after an annealing step at 700 °C for 30 s and consequently, it forms either a SiC/Ni silicide heterostructure or a fully Ni silicidized SiC NW depending on the channel length. A fully silicidized SiC NW exhibits a low channel resistance (740 Ω) and a high current density (1.46 × 107 A cm−2 at 1.4 V). The needle shape of SiC NWs is transformed into a bead necklace like morphology after Ni silicide intrusion.