Microfabrication of extraction electrodes for local-electrode atom probes

The local-electrode atom probe (and scanning atom probe) is a recently proposed innovation in atom probe technology. An important step in itʹs development is the fabrication of suitable local-extraction electrodes. Several techniques are currently being devised to fabricate these electrodes. One uses focused ion beam milling to drill an aperture at the apex of a conical nickel shell. Electrodes are also being fabricated using various micromachining techniques on silicon. The feasibility of optical alignment of specimen and electrode is explored. Optically transparent electrodes are under development to facilitate the use of this alignment technique. This paper discusses details of the electrode fabrication processes and presents initial results.