Nanoscale effects in focused ion beam processing

Abstract

Focused ion beams with diameters of 8 to 50 nm are used for material processing in the nanoscale regime. In this paper, effects of the ion beam-solid interaction determining the formation of small structures by ion-beam sputtering and chemically assisted material deposition and etching are investigated. In the case of decreasing feature size, angle-dependent sputtering, a non-constant sputter rate, and scattered ions play an important role. The impact on side-wall angle, aspect ratio, and shape of the bottom of the etched structures is discussed. In beam tail regions, these effects will be especially pronounced, leading to material swelling instead of material removal. Ion beam assisted etching and deposition will face additional effects. For small structures, gas depletion becomes a significant drawback. The impact on gas depletion and the competition with sputtering are discussed

Focused ion beam induced deflections of freestanding thin films

“…It has been widely recognized that ion beams often induce compositional and morphological changes on solid surfaces due to atomic displacement, structural damage, sputter erosion, hydrocarbon contamination, and ion implantation. [1][2][3][4][5][6] While such effects may in some situations be detrimental, they may also be exploited to create or tailor nanostructures. For example, the increased etch resistance of silicon caused by Ga + doping has been exploited to generate etch masks for anisotropic etching, 5 and Ar + ion beams have been used to sculpt nanopores and other fine nanostructures in thin silicon nitride membranes.…”

Focus Ion Beam/Scanning Electron Microscopy Characterization of Osteoclastic Resorption of Calcium Phosphate Substrates

“…Drobne et al, as well as other authors, extensively described the potential of FIB milling to process biological samples and shed light on the optimal processing parameters in order to avoid shrinkage, melting effect, Ga + implantation or side-wall artefacts. 18,[27][28][29][30] These effects can be effectively reduced by a first Pt layer deposition which protects the sample surface against re-deposition of ablated atoms, provides mechanical stability and reduces curtain effects. In addition, damage can be minimized by working with low ion beam currents and low acceleration voltages, especially during the final steps of the crosssection polishing.…”

“…In addition, damage can be minimized by working with low ion beam currents and low acceleration voltages, especially during the final steps of the crosssection polishing. 29 All these strategies have been applied in the present study to investigate a series of three apatitic substrates consisting of two biomimetic formulations and a sintered material. As illustrated in Figure 1g, resorption pits were easily visualized on some substrates (white arrows), namely sintered HA, where typical 30-50µm sized resorption lacunae were observed.…”

Application of Focused Ion Beam Micromachining: A Review

“…Taper angle is exhibited during FIB sputtering of microfeatures that requires depth or height such as microholes. The trend of the Gaussian profile and redeposition effect was found to be the cause of this taper angle existence [6,10]. This phenomenon shows that the actual geometry shape for microholes may deviate from the desire shape [6].…”

“…R a was found to be the most crucial factor in producing good surface quality of micrcomponents [14,15,16]. Researchers have found that the sidewall R a is estimated to be below 100 nm when sputtering GaN by using a lower beam current since a large beam diameter is produced when a high beam current is used [10,14]. Material removal rate, MRR in physical sputtering depends on parameters such as dwell time.…”