Field-ion specimen preparation using focused ion-beam milling

Preparation of field-ion specimens from various materials has been accompli shed using focused ion-beam milling in either a simple cutting mode or by a pplication of an annular-shaped ion-milling pattern. These specimens have b een investigated using field-ion microscopy and three-dimensional atom prob e analysis. In the cutting mode, gallium implantation is minimised when usi ng a lower beam energy. However, with annular milling, using 30 keV ions op posed to 10 keV ions results in less gallium implantation and produces a sm aller shank angle and a sharper apex radius. High-dose ion imaging at 30 ke V ion energy, even with relatively low beam currents, results in excessive implantation during held-ion specimen fabrication. Focused ion-beam milling provides not only an alternative method of field-ion sample preparation, b ut also, in conjunction with atom probe analysis, allows the quantitative i nvestigation of the gallium implantation and damage which occurs during the milling. (C) 1999 Elsevier Science B.V. All rights reserved.