Chemical-vapour-deposition growth and electrical characterization of intrinsic silicon nanowires

In this work, we present the elaboration and the electrical characterisation of undoped silicon nanowires (SiNWs) which are grown via vapour–liquid–solid mechanism using Au nucleation catalyst and SiH4 as the silicon source. The nanowires were investigated by high-resolution transmission electron microscopy. An electrical test structure was realized by a dispersion of the nanowires on SiO2/Si substrate with photolithography pre-patterned Au/Ti microelectrodes. The connexion is made on a single nanowire using a cross beam plate form allowing scanning electron microscopy imaging and the deposition of tungsten wiring by focussed ion beam deposition. The current–voltage characteristics of the nanowires are linear which indicates an ohmic contact between tungsten allow and SiNWs. The total resistance of the nanowires increases from 135 MΩ to 5 GΩ when the diameter decreases from 190 to 130 nm. This effect is may be due to the reduction of the conductive inner volume of the nanowires and to charged defects at the Si–SiO2 interface if we assume that the contact resistance is constant. Moreover, gate-dependent current versus bias voltage measurement show that the nanowires exhibit a field effect response characteristic of a p-type semiconductor.