Preparation of different protected bimetallic nanoelectrodes with 30nm gapwidth and access window

Reproducible fabrication of 30 nm metallic nanogaps on silicon chips and their electrochemical characterization are presented. The fabrication of the chip is a combination of an optical lithography step and two electron-beam (e-beam) steps. An optimized adhesion layer/metal layer combination (Ti/Pt/Au) and an adopted two layer e-beam resist are used. Specifically the chip has been covered with different protection layers, except of an access window located on top of the nanogaps, calibration electrodes and contact pads, respectively (Fig.1). After characterising the gaps and of the protection layer by cyclical voltammetry in 0.1 M H$_2$SO$_4$ aqueous electrolyte, the deposition of Cu onto the nanogaps will be presented. Fig.1: Different Nanoelectrode Strcutures with access window on top covered by SiO$_2$/Si$_3$N$_4$/SiO$_2$ used as protection layer.