Nanoscale electrical contacts grown by focused ion beam (FIB)-induced deposition

Abstract

A detailed description of the use of the focused ion beam (FIB) to grow electrical contacts is presented. The combination of FIB with precursor compounds, which are delivered on the area of interest by means of gas-injection systems, allows the growth of electrical contacts with nanometric resolution on targeted places. The technique has been coined focused ion beam-induced deposition (FIBID). Pros and cons with respect to other existing techniques for contacting are discussed. The FIBID contacts reported in this chapter are based on the use of Pt and W precursors, which result in the growth of deposits with resistivities down to 100 μΩ cm without any post-treatment. A comparison of FIBID with focused electron beam-induced deposition, the sister technique that uses focused electrons instead of ions, is also presented. The steps to follow in order to be successful in the contacting process by means of FIBID are described. Examples of the contacting to individual nanowires and nanoparticles carried out in our laboratory are shown, together with the corresponding four-probe transport measurements. Below 5 K, W deposits are superconducting and can be therefore used for zero-resistance lead contacts, superconductor-based nanocontacts and probing of proximity effects, opening new perspectives as described here.