Focused Ion Beam Fabrication of Sub-20nm Inter-Electrode Gaps for Room Temperature Operating Single Electron Transistor

Fabricating nanoelectrodes with a few nanometer inter-electrode gap laterally is a challenge with existing technologies. In this work, we present a simple method to fabricate electrode pairs with a sub-20 nm inter-electrode gaps using Focused Ion Beam (FIB) etching technology. Unlike previously reported methods, no internal or external modification in the Focused Ion Beam system is needed in this technique. An inter-electrode gap of 17 nm in a Cr electrode pair is successfully fabricated by optimizing the thickness of the Cr film. This fabrication technique is further applied to realize the source drain and gate electrodes with a targeted inter-electrode gap of 20 nm, for room temperature operating Single Electron Transistors.