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Abstract. Maskless fabrication techniques of nanoelectrode with nanogaps are investigated, which use sputter etching technique by Ga focused ion beam (FIB). The etching steps are reliably controlled in-situ by monitoring a current fed to the films. 30 keV Ga FIB with a beam size of 12 nm is irradiated on double layer films consisting of 10-30 nm thick Au top conducting layer and 1-2 nm thick Ti bottom adhesion layer to form nanowires and gaps. The films are deposited on a silicon substrate on which 200 nm of oxide has been thermally grown and patterned to define 5-7 ƒÊm wide strips by photolithography and Ar sputter etching. By the present techniques nanogaps with a width much smaller than a beam diameter are fabricated. The minimum gap width of ~3 nm and the highest gap resistivity of ~80 Gƒ¶ are obtained.
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