Focused Electron Beam-Based 3D Nanoprinting for Scanning Probe Microscopy: A Review

Abstract

Scanning probe microscopy (SPM) has become an essential surface characterization technique in research and development. By concept, SPM performance crucially depends on the quality of the nano-probe element, in particular, the apex radius. Now, with the development of advanced SPM modes beyond morphology mapping, new challenges have emerged regarding the design, morphology, function, and reliability of nano-probes. To tackle these challenges, versatile fabrication methods for precise nano-fabrication are needed. Aside from well-established technologies for SPM nano-probe fabrication, focused electron beam-induced deposition (FEBID) has become increasingly relevant in recent years, with the demonstration of controlled 3D nanoscale deposition and tailored deposit chemistry. Moreover, FEBID is compatible with practically any given surface morphology. In this review article, we introduce the technology, with a focus on the most relevant demands (shapes, feature size, materials and functionalities, substrate demands, and scalability), discuss the opportunities and challenges, and rationalize how those can be useful for advanced SPM applications. As will be shown, FEBID is an ideal tool for fabrication/modification and rapid prototyping of SPM-tipswith the potential to scale up industrially relevant manufacturing.

Mechanical Properties of 3D Nanostructures Obtained by Focused Electron/Ion Beam-Induced Deposition: A Review

“…All the impinging electrons will enter the pillar apex within the focus spot area of the electron beam and then spread and dilute until they exit the pillar in the backward (BSE) or forward (FSE) direction, as schematically shown in Figure 2c. The broadening of the primary electron beam within the tip apex is responsible for the conical pillar apex shape, as shown in Figure 2d and shown in slightly more detail in another review article by Plank et al [67]. The pillar also grows laterally due to SE generation close to the surface, which emerges due to the inelastic collision events along the primary electron trajectories.…”

“…The abbreviation a-C:H,O,F reads as amorphous carbon being hydrogenated, oxygenated, and/or fluorinated. [64] FEB: [60][61][62][63][64][65][66][67][68][69][70] No FIB data * Literature references in these two columns differ from column one (left) when no composition data was found there.…”

Combined Ammonia and Electron Processing of a Carbon-Rich Ruthenium Nanomaterial Fabricated by Electron-Induced Deposition

“…Ru ratio indicates that C was lost from the deposit and replaced by N. Note that the C:N ratio of the obtained material is that of a typical carbon nitride, i.e., C3N4 [16][17][18]. We note that the density of amorphous C3N4 (1.3-1.4 g/cm 3 [29]) as compared to that of a RuC9 deposit (3.2 g/cm 3 [9]) can account for a volume increase of roughly 230-250%. A height increase of ~220% (see Supplementary Materials, Figure S2) compares well with this estimate.…”

“…Here, we demonstrate that electron irradiation, in the presence of ammonia (NH 3 ), performed on carbon-rich deposits produced from the organometallic precursor (EtCp) 2 Ru, converts the carbonaceous matrix to a material with the typical composition of carbon nitride (C 3 N 4 ). This study builds on our previous work regarding the electron-induced chemistry of NH 3 . With respect to FEBID applications, we demonstrated that chlorine-contaminated ruthenium deposits produced from η 3 -allyl ruthenium tricarbonyl chloride (η 3 -C 3 H 5 )Ru(CO) 3 Cl can be purified by electron exposure in the presence of NH 3 [20].…”

“…Nanoscale materials fabricated by focused electron beam-induced deposition (FEBID) drive the development of novel devices for a variety of applications [1][2][3]. In FEBID, volatile precursor molecules that contain an element of the desired material are adsorbed on a surface and fragmented under a tightly focused electron beam.…”