AFM lithography for the definition of nanometre scale gaps: Application to the fabrication of a cantilever-based sensor with electrochemical current detection

The concept, design and fabrication of a cantilever-based sensor operating in liquid for biochemical applications are reported. A novel approach for detecting the deflection of a functionalized cantilever is proposed. It consists of detecting the change of the electrochemical current level when a voltage is applied between a deflecting cantilever, acting as one of the electrodes, and a reference fixed electrode placed in close proximity to the free extreme of the cantilever. The detection is possible since the distance between the two electrodes is smaller than 50 nm. The sensor is fabricated by using a combination of MEMS technology and AFM-based lithography.