Formation of Metal-Semiconductor Axial Nanowire Heterostructures through Controlled Silicidation Undergraduate Researcher

Semiconductor nanowires show promise for application in nanoscale electronics, but the difficulty of forming low-resistance ohmic contacts provides a challenge to their implementation. To improve the electrical performance of lithographically defined nickel contacts, nickel-silicide/ silicon axial nanowire heterostructures were formed by controlled partial silicidation. Prior to annealing, two-terminal silicon nanowire devices had nonlinear and asymmetric current-voltage behavior indicative of poor electrical contacts. After the formation of heterostructure contacts, nanowire devices carried increased current, pointing to reduced contact resistance, and a larger fraction of nanowire devices exhibited linear current-voltage characteristics. A study of the silicidation kinetics revealed a linear growth rate of 0.2 μm/min, suggesting the rate may be limited by the silicidation reaction at the interface.