Fabrication of dissimilar metal electrodes with nanometer interelectrode distance for molecular electronic device characterization

We report a versatile process for the fabrication of dissimilar metal electrodes with a minimum interelectrode distance of less than 6 nm using electron beam lithography and liftoff pattern transfer. This technique provides a controllable and reproducible method for creating structures suited for the electrical characterization of asymmetric molecules for molecular electronics applications. Electrode structures employing pairs of Au electrodes and non-Au electrodes were fabricated in three different patterns. Parallel electrode structures 300 mu m long with interelectrode distances as low as 10 nm, 75 nm wide electrode pairs with interelectrode distances less than 6 nm, and a multiterminal electrode structure with reproducible interelectrode distances of 8 nm were realized using this technique. The professing issues associated with the fabrication of these structures are discussed along with the intended application of these devices. (C) 2000 American Vacuum Society. [S0734-211X(00)03903-2].