Focused ion-beam milling for field-ion specimen preparation: preliminary investigations

Focused ion-beam milling has been used to fabricate field-ion specimens from a pure metal, a metal alloy, an intermetallic alloy and a multilayer film device. Gallium ions of 30 keV energy with beam currents of 4-1000 pA were used for micromachining of the field-ion specimens and for simultaneous imaging. The final sharpening for pure metal and intermetallic specimens and the entire sharpening procedure for a metal alloy sample and a multilayer film structure containing 100 repetitions of a Cu-2 nm/Co-2 (nm) bilayer were accomplished using the focused ion-beam system, Atom probe analysis indicated that although the amount of gallium implantation was minimal in a Cu-15% Co alloy, significant damage occurred in Cu/Co multilayer film structures prepared by focused ion-beam milling. Focused ion-beam techniques provide an alternative to traditional electropolishing methods for field-ion specimen preparation and atom probe analysis provides quantitative information of implanted gallium and ion-induced damage in such samples. (C) 1998 Elsevier Science B.V. All rights reserved.