Multiple Double Cross-Section Transmission Electron Microscope Sample Preparation of Specific Sub-10 nm Diameter Si Nanowire Devices

Abstract

The ability to prepare multiple cross-section transmission electron microscope (XTEM) samples from one XTEM sample of specific sub-10 nm features was demonstrated. Sub-10 nm diameter Si nanowire (NW) devices were initially cross-sectioned using a dual-beam focused ion beam system in a direction running parallel to the device channel. From this XTEM sample, both low- and high-resolution transmission electron microscope (TEM) images were obtained from six separate, specific site Si NW devices. The XTEM sample was then re-sectioned in four separate locations in a direction perpendicular to the device channel: 90° from the original XTEM sample direction. Three of the four XTEM samples were successfully sectioned in the gate region of the device. From these three samples, low- and high-resolution TEM images of the Si NW were taken and measurements of the NW diameters were obtained. This technique demonstrated the ability to obtain high-resolution TEM images in directions 90° from one another of multiple, specific sub-10 nm features that were spaced 1.1 μm apart.

Vertical III–V Nanowire Device Integration on Si(100)

“…In one specific case, a sample that was initially cross-sectioned and analyzed in the TEM was then placed back in the DB-FIB and resectioned in the direction perpendicular to the [110], forming a planview (or top-down) section of the previously sectioned nanowires. 26 Single GaAs nanowires were investigated by μ-PL using a spectrometer equipped with a He−Ne laser (λ = 633 nm, power < 15 μW/μm 2 ) and a liquid-N 2 -cooled CCD detector. For investigation of the electrical properties, Si(100)-InAs diodes were fabricated by etching away the empty part of the template by a timed buffered HF etch, leaving a SiO 2 insulation layer on the substrate and side walls of the nanowires.…”

“…In contrast, InAs nanowires with horizontal top facets appear stacking-fault-free when viewed in the [11̅ 0] direction (Figure 5b). However, when viewed along the [110] direction in cross-sectional images 26 (the planview image in Figure 5d), the (11̅ 1)-oriented stacking faults that run vertically through the entire length of the nanowire become visible. The observation of differences in stacking-fault orientation can explain the existence of the two distinct facet morphologies (Figure 3c and d).…”

A Method for Directly Correlating Site-Specific Cross-Sectional and Plan-View Transmission Electron Microscopy of Individual Nanostructures

“…7d) as a light ring around the NW, and also of faceting of the Si-NW. This is significant as other multiview FIB preparation techniques typically result in damage of the outer 10 nm of the specimen (De Veirman, 2003; Gignac et al, 2011; Hertog et al, 2012). Thus, the FIB lift-out from a drop-cast plan-view TEM specimen on a standard TEM grid provides a uniquely clean cross-sectional view of the entire NW diameter.…”

“…In the semiconductor industry, for example, TEM samples of failed devices for both plan-view and cross-section imaging (De Veirman, 2003; Hillmann et al, 2009) are prepared routinely. Observing a 1D nanostructure such as a single NW in both orientations is nontrivial but has recently been demonstrated (Gignac et al, 2009, 2010, 2011) for semiconductor devices that consisted of lithographically-defined Si nanowires produced using a top-down fabrication approach. In their work, Gignac et al first cross-sectioned a Si-NW device to produce a plan-view TEM image of the Si-NW to measure the gate length.…”

Fundamentals and Applications of Scanning and Transmission Electron Microscopes

“…Non-conducting samples tend to be charged electrically when they are swept by the electron beam causing sweeping defects, distortions and mirages in the generated image, especially when the secondary electrons are used to form the image. It is advisable to deposit an ultrafine layer of a conductive material on the surface of the non-conducting samples, this ultra-thin layer generally formed of metals such as gold, gold-palladium alloys, platinum, osmium, iridium, tungsten, chromium and graphite, among others [19,20].…”