Ultra-low contact resistance of epitaxially interfaced bridged silicon nanowires

Laterally oriented single-crystal silicon nanowires are epitaxially grown between highly doped vertically oriented silicon electrodes in the form of nanobridges. Resistance values extracted from the current-voltage measurements for a large number of nanobridges with varying lengths and diameters are used to propose a model which highlights the relative contribution of the contact resistance to the total resistance for nanowire-based devices. It is shown that the contact resistance depends on the effective conducting cross-section area and hence is influenced by the presence of a surface depletion layer. On the basis of our measured data and constructed model, we estimated the specific contact resistance to be in the range 3.74 x 10(-6) to 5.02 x 10(-6) Omega cm2 for our epitaxial interfacing method. This value is at least an order of magnitude lower than that of any known contact made to nanowires with an evaporated metal film, a common method for integrating semiconductor nanowires in devices and circuits.