SCANNING-TUNNELING-MICROSCOPY BASED LITHOGRAPHY OF OCTADECANETHIOL ON AU AND GAAS

We have demonstrated that low energy electron beams (less-than-or-equal-to 10 eV) from a scanning tunneling microscope (STM) can be used to modify a surface of self-assembled monolayers of octadecanethiol [ODT, CH3(CH2)17SH] on gold and GaAs. STM modification in air was used to produce grating patterns up to 140 mum in total size. Line sizes as small as 15 nm were produced in ODT on GaAs at a bias of 10 V, and slightly larger sizes were produced on the gold substrate. Biases of greater than 4 V are necessary for the fabrication of these raised lines, as observed with an atomic force microscope (AFM). The patterns in ODT on gold were successfully transferred into the gold layer with a wet chemical etch demonstrating that the monolayer performs as a positive electron beam resist.