Investigation of surface amorphization of silicon wafers during ion-milling

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

“…10). This roughly agrees with the thickness of the amorphized surface layers determined from cross sections of Si TEM lamellae reported by Schuhrke et al (1992). As the specimen is at least 10 times thicker, the amorphization does not significantly deteriorate the image contrast.…”

“…If the original structure of the sample is to be imaged, these layers must be thin relative to the thickness of the specimen. It is well known that amorphized surface zones form during ion milling, whose depth depends on ion energy and incidence angle (Barna et al, 1999;McCaffrey et al, 2001;Schuhrke et al, 1992). For the LAIB milled specimens, HRTEM images document that the amorphized zone of the specimen edge has a lateral width of $1 nm (Fig.…”

“…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 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.…”

Transmission electron microscopy: A critical analytical tool for ULSI technology

“…In addition, ion-beam induced compositional mixing of adjoining layers of material severely degrades analytical data obtained by EDS or EELS. Clearly, there is an emerging industry-wide need to develop site-specific approaches to TEM sample preparation that produce significantly less surface damage, Argon ion milling is the only technique known now to provide thin specimens with significantly less surface amorphization than that provided by gallium FIB systems [22]. However, the endpoint control that can provide thin, centered cross-sections of small structures does not exist.…”