Correlating dopant distributions and electrical properties of boron-doped silicon nanowires

Abstract

Quantitative nonuniform radial doping profiles in vapor liquid solid grown boron-doped silicon nanowires are correlated with axial variations in electrical properties. Boron concentrations measured by atom probe tomography are lower for the core material grown from a gold catalyst than for material deposited on the nanowire surface. Transistors fabricated along a single nanowire exhibit a transition from nonlinear contact-dominated behavior to linear behavior with increasing thickness of the dopant-enriched surface layer. Simple models confirm that the surface is doped to a level that enables the contact resistance to become comparable to the channel resistance, suggesting that unintentional surface doping may play a role in lowering contact resistances in some nanowire devices.