Size-reduced silicon nanowires: Fabrication and electrical characterization

Silicon nanowires of diameters down to 100 nm and typical lengths of 1-3 μm have been fabricated in silicon-on-insulator material by electron beam lithography and plasma etching. They were subsequently size-reduced by photoelectrochemical etching resulting in wire widths down to 10 nm. To enable accurate control of the photoelectrochemical size-reduction, a micro-electrochemical cell was developed, enabling single nanowires to be exposed to the etching solution while being illuminated by a laser or a lamp. The arrangement allows contact leads to be extended to metal contact pads located outside the cell, which can be connected by probes, allowing in situ electrical characterization of a nanowire during etching. In this paper, we describe the experimental setup, the fabrication method and show examples of achieved wire widths together with some preliminary results from the electrical characterization.