Comparative study of ion milling techniques in cross‐sectional transmission electron microscope specimen preparation

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

“…The requirements for ion-milled TEM samples with many square microns of uniformly thin material in a selected area, a minimally thick amorphous layer on the top and bottom surfaces of the sample, and minimal preferential etching (one material sputtering faster than an adjacent material) have led to studies of these effects and improvements in sample preparation techniques and in the design of ion mills. Minimizing the incident ion angle to the surface of the sample has been found to be one of the most effective techniques for fulfilling these requirements (McCaffrey et al, 1992;Schuhrke et al, 1992;Zielinski and Tracy, 1992). Results of these studies indicate that the lower the incident ion beam angle to the sample, the fewer the artifacts that are produced.…”

Preparation of high‐quality ultrathin transmission electron microscopy specimens of a nanocrystalline metallic powder

“…An ideal TEM specimen is described as an object having a uniform low thickness, conserving the original sample structure concerning the lattice geometry as well as chemistry, and displaying no oxidation and contamination surface layers (Egerton et al, 2004;McCaffrey and Barna, 1997). For preparing high-quality, low-thickness TEM specimens of a wide range of materials classes, broad-beam low-angle ion beam (LAIB) milling has been proved beneficial (McCaffrey and Barna, 1997;McCaffrey et al, 1992;Schuhrke et al, 1992;Strecker et al, 1999;Zielinski and Tracy, 1992), although, due to the small ablation rates at low angles, it is a time-consuming procedure depending on the thickness achieved by the mechanical prethinning. Here, thin-grinding by means of the Tripod/T-tool technique has the advantage of producing very flat and thin specimen discs (Anderson and Klepeis, 1997;Benedict et al, 1992;Zhang, 1998Zhang, , 2002.…”

Preparation for TEM of layered samples with fragile microstructure and weak layer interface

“…These observations referred to an ion milling angle of 15°. Zielinski and Tracy (1992) compared different ion milling techniques. Shallow angle milling (e.g., 4°) is a useful method that creates large thin areas.…”