Nickel Monosilicide Contact Formation in Electrolessly Etched Silicon Nanowires Deposited onto Nickel Electrodes

Large arrays of silicon nanowires are fabricated by electroless etching of (100) p-type silicon wafers: The nanowires are separated from substrates, deposited onto interdigitated nickel electrodes, and annealed to form silicide contacts. Two-probe electrical characterization of interdigitated electrodes with hundreds of silicided nanowires deposited across electrode pairs shows a linear current-voltage behavior with an estimated nanowire resistivity approximately equal to the parent wafer. Results from X-ray photoelectron spectroscopy and X-ray absorption near-edge structure show the formation of a nickel monosilicide (NiSi) phase near the tips of nanowires adjacent to nickel reservoirs during an anneal. The work shows that a facile and nonvacuum process may be used to create ohmic contacts between high volumes of nanowires and pre-existing electrodes. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3122703] All rights reserved.