Low energy focused ion beam milling of silicon and germanium nanostructures

Abstract

In this paper focused ion beam milling of very shallow nanostructures in silicon and germanium by low energy Ga( + ) ions is studied with respect to ion beam and scanning parameters. It has been found that, using low energy ions, many scanning artefacts can be avoided and, additionally, some physical effects (e.g. redeposition and ion channelling) are significantly suppressed. The structures milled with low energy ions suffer less subsurface ion beam damage (amorphization, formation of voids) and are thus more suitable for selected applications in nanotechnology.

Three‐dimensional nanofabrication of polystyrene by focused ion beam

“…There is no large disparity in terms of milled depth, given the fact that the beam currents and beam exposure times are similar in all cases. This implies that the milling rate, and therefore the milled depth is strongly affected by the beam current and exposure time, but much less strongly affected by the beam voltage, consistent with the observations of others (Kolibal et al ., 2011). Although it has little effect on the milling rate, the beam voltage can be used to control the depth of damage caused by ion implantation (Yao, 2007; Felfer et al ., 2011).…”

“…FIB micromachining and the associated heating can be detrimental to the fabricated polymer structures if optimum conditions are not used. Methods used to eliminate gallium damage and implantation in metals and semiconductors such as performing low ion energy milling on the structure (Felfer et al ., 2011; Kolibal et al ., 2011) or post‐annealing the structure at elevated temperature (Kupfer et al ., 2010) may not be sufficient to effectively remove the damage in polymers as the estimated damaged region is comparatively deeper (∼50 nm at 10 kV) and due to thermal effects, where the generation of local heat is more significant in polymers than in metals and semiconductors, under similar beam conditions.…”

“…FIB micromachining and the associated heating can be detrimental to the fabricated polymer structures if optimum conditions are not used. Methods used to eliminate gallium damage and implantation in metals and semiconductors such as performing low ion energy milling on the structure (Felfer et al, 2011;Kolibal et al, 2011) or post-annealing the Fig. 8.…”

Liquid-like behaviour of gold nanowire bridges

“…The milling strategy was to perform two identical rectangular raster scans, sequentially, to form a gold on silicon supported nanowire with length parallel to the longer sides of the scan boxes. The resulting nanowire will have received a small collateral dose of Ga + ions due to the beam tails [8], but this process is different from that of Li et al [1], who deliberately subjected their gold nanostructures to a broad area, bulk irradiation, with a defined dose of Ga + ions in order to observe its effect on surface morphology, including shrinking of features.…”

Focused Ion Beam Nanoscale Patterned Transmission-Enhanced Fiber-Optic Tips

“…20 21 FIB has its strength in one-step maskless simpler, more flexible, and better-controlled nano-precision machining, patterning and fabrication especially for various submicron or nanoscale functional samples or devices via ion beam induced milling, etching and deposition due to its advantages of large depth of focus, high resolution, patterning flexibility, and direct-writing capability. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] In addition, another advantage of FIB is that it can be conveniently used to machine the biology to analyze its nanophotonic structures, 35 and FIB nanopatterning can be further used to fabricate the designed nanoscale devices inspired by the observed biophotonic structures. So far, although FIB has been widely used for nanopatterning and nanofabrication for some nanodevices/nanostructures, only a few literatures regarding FIB nanopatterning on the metallically-coated flat-top fiber endfaces can be referred to, and these fiber endface nanostructures were actually fabricated on the cleaved coarse fiber tips, 1 16-18 i.e., the used fiber tip diameters were equal to the optical fiber diameters instead of the thinner tapered/angled fiber tips.…”