Interdigitated 50 nm Ti electrode arrays fabricated using XeF2 enhanced focused ion beam etching

The fabrication of interdigitated titanium nanoelectrode arrays of 50 nm in width and spacing is described in this work. The nanoarrays have been realized using a Ga+ focused ion beam (FIB). FIB milling is typically accompanied by redeposition of removed material, which represents an important hindrance for milling closely spaced nanostructures. Redeposition effects have been reduced by means of XeF2 gas assistance, which increases the etch yield by a factor of seven compared with pure ion milling. Furthermore, we used a simple adsorption model, which led to the conclusion that dwell time and refresh time should be <500 ns and >30 ms, respectively, for optimized XeF2 assisted Ti milling. The measured resistance R of the electrodes is higher than 1 GΩ