In situ nanowire growth for electrical interconnects

We report a technique to grow a single tungsten nanowire at a predetermined location by using field emission in a low-pressure tungsten carbonyl atmosphere. A sharp tip is first made to contact the intended location of growth. Electrical current is then passed through the contact. When the contact is broken, the resulting localized plasma discharge at the point of breakage causes a nanowire to initiate. Continued growth at low currents results in a single nanowire a few nanometres in diameter and up to tens of micrometres in length. The nanowire is overcoated by a thin carbon layer which protects the metal core from oxidation and corrosion. Electrical measurements of nanowires grown between two pads show resistivity one to two orders of magnitude higher than that of bulk tungsten. The technique can be applied to the interconnection of nanostructures to electrodes on a die.