Deposition of gold nanofeatures on silicon samples by field-induced deposition using a scanning tunneling microscope

Gold islands of diameter as small as 15 nm and 6 nm high were deposited on a standard silicon (100) surface by field-induced deposition using a scanning tunneling microscope operating with Pt or W tips coated by a gold film. Gold atoms are transferred by applying to the sample negative voltage pulses of few volts in magnitude, and of some tens of microseconds in duration. The scanning tunneling microscope tip morphology and composition have been analyzed systematically by field-emission gun scanning electron microscope plus energy dispersive x-ray (EDX) microanalysis before and after its use for lithography. The deposits composition have also been analyzed by EDX. Finally, preliminary results on trials of direct bonding of microscopic contact leads are presented.