Electrothermal modelling for EIBJ nanogap fabrication

Fabrication of electrodes with a controlled nanometric separation is strategic for many application fields as molecular electronics and biosensors. A technological process at room temperature with an high yield can be defined starting from electromigration induced break junction technique (EIBJ). A self assembly adhesion molecule (MPTMS (3-mercaptopropyl)trimethoxysilane) for gold, efficiently used in previous works, solves the problems of metallic residuals, typical of titanium and chromium. As a consequence a simple and low cost technological process to realise gold nanogaps at room temperature becomes feasible. The analysis of internal mechanisms that act on metal wire, when the density produces electromigration, together with a thermal model of the wire itself, can be used to control nanogap dimension. The design of a large set of wires, where different geometries are used to modify their thermal behaviour during electromigration, is used to verify feedback algorithms to control applied bias voltage. Some interesting experimental results seem to confirm the model proposed by the authors, opening new opportunities for future high yield nanogap fabrication.