Preparation of cross-sectional TEM samples for low-angle ion milling

The ideal ion-milled transmission electron microscope (TEM) sample would contain large, thin areas in selected regions, minimal top and bottom surface amorphization, and minimal preferential etching of adjacent materials. This desire has led to studies of these effects and improvements in designs and techniques for ion mills. Minimizing the incident angle of the ion beam to the surface of the sample has been found to be one of the most effective techniques for fulfilling these requirements. A new generation of ion mills has recently been designed to allow low-angle ion milling for the production of very high quality cross-sectional TEM samples. To take advantage of the low-angle ion milling capabilities and high-powered ion sources in these mills, new sample preparation techniques are required. In this paper, a simple technique of mounting material in a specialized titanium grid for cross-sectional TEM sample preparation is presented. This technique is designed to take full advantage of the powerful capabilities of these new low-angle ion mills.