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Focused ion beam (FIB) milling techniques have been used for more than a decade to prepare organic-rich shale samples for electron microscopy. Nano- and micro-scale imaging of organic pores is used to assess pore volumes and hence estimate gas-in-place. Ion milling natural composites is particularly challenging due to drastic extremes in the physical properties of individual phases such as minerals and organics. Damage to the organic-rich phases occurs due to the large differences in thermal conductivities of minerals and organics that could reach an order of magnitude and the resulting buildup of heat in the organics. Furthermore, radiation damage via ion implantation may also alter the structural characteristics of the shale. Herein, the damage associated with preparing electron-transparent kerogen specimen using low kV FIB, cryo-FIB, and cryomicrotome, a new technique for shale kerogen, is quantified using experimental and modeling techniques. The degree of gallium implantation is quantified using scanning transmission electron microscopy (STEM), selected area electron diffraction (SAED), and energy dispersive X-ray spectroscopy (EDX) along with the stopping range of ions in matter (SRIM) model. Interestingly, although the use of cryogenic temperature removes the thermal effect, Ga+ ion implantation is observed in the specimen prepared by cryo-FIB. Furthermore, the magnitude of the thermal damage at a highly localized level was determined using nano-beam electron diffraction (NBED) performed at −196 °C. Time-resolved diffraction patterns indicate that despite the fact kerogen is among the most stable geopolymers, the aromatic components still degraded due to the local temperature increases. On the other hand, the cryomicrotome technique operating at liquid nitrogen temperature is demonstrated as a suitable method to prepare thin kerogen specimen while minimizing structural damage and preserving its native porosity and chemical composition.

This article presents an examination of well-controlled patterns created using a Ga+-based focused ion beam (FIB) on glass, while silicon substrates were used to evaluate the FIB performance by its achievable feature size versus time constraints. The pattern creation on glass was developed with the aim of studying potential surface-enhanced Raman spectroscopy (SERS) applications. Furthermore, the FIB was used to create dimer systems of periodically and randomly positioned dumbbell-shaped pits on the glass (each dimer occupies an area of 203 × 87 nm2). By following the bitmap pattern files, the FIB ensured there was 3000 dimer fabrication over a 20 × 20 μm2 large area, with a pit size and position variation below 10 nm. The article highlights that FIB can be used for precise large-area nano-fabrication. The gold nanoparticle dimers were formed on the prepatterned surface via capillary force-assisted deposition. The fabricated nanostructures were tested in SERS measurements. The enhancement factor for Rhodamine B molecule reached ~105, demonstrating the potential application of the method to create nanostructures in the sensor domain. [ABSTRACT FROM AUTHOR]

Pyrenoids are subcompartments of algal chloroplasts that increase the efficiency of Rubisco-driven CO 2 fixation. Diatoms fix up to 20% of global CO 2 , but their pyrenoids remain poorly characterized. Here, we used in vivo photo-crosslinking to identify pyrenoid shell (PyShell) proteins, which we localized to the pyrenoid periphery of model pennate and centric diatoms, Phaeodactylum tricornutum and Thalassiosira pseudonana. In situ cryo-electron tomography revealed that pyrenoids of both diatom species are encased in a lattice-like protein sheath. Single-particle cryo-EM yielded a 2.4-Å-resolution structure of an in vitro TpPyShell1 lattice, which showed how protein subunits interlock. T. pseudonana TpPyShell1/2 knockout mutants had no PyShell sheath, altered pyrenoid morphology, and a high-CO 2 requiring phenotype, with reduced photosynthetic efficiency and impaired growth under standard atmospheric conditions. The structure and function of the diatom PyShell provide a molecular view of how CO 2 is assimilated in the ocean, a critical ecosystem undergoing rapid change. [Display omitted] • Identification of the PyShell, a protein sheath that surrounds diatom pyrenoids • Multiscale imaging of PyShell lattices from in situ architecture to in vitro structure • PyShell knockout disrupts pyrenoid morphology and function, impairing cell growth • The PyShell is widely conserved, enabling much of the ocean's CO 2 fixation Identification and characterization of a protein lattice around the pyrenoid compartments of diatoms reveals that these prolific marine algae evolved a distinct pyrenoid architecture to promote Rubisco's CO 2 -fixing activity. [ABSTRACT FROM AUTHOR]

In recent years, the field of micro- and nanochannel fabrication has seen significant advancements driven by the need for precision in biomedical, environmental, and industrial applications. This review provides a comprehensive analysis of emerging fabrication technologies, including photolithography, soft lithography, 3D printing, electron-beam lithography (EBL), wet/dry etching, injection molding, focused ion beam (FIB) milling, laser micromachining, and micro-milling. Each of these methods offers unique advantages in terms of scalability, precision, and cost-effectiveness, enabling the creation of highly customized micro- and nanochannel structures. Challenges related to scalability, resolution, and the high cost of traditional techniques are addressed through innovations such as deep reactive ion etching (DRIE) and multipass micro-milling. This paper also explores the application potential of these technologies in areas such as lab-on-a-chip devices, biomedical diagnostics, and energy-efficient cooling systems. With continued research and technological refinement, these methods are poised to significantly impact the future of microfluidic and nanofluidic systems. [ABSTRACT FROM AUTHOR]

The residual stress greatly affects the mechanical behavior of a material. In this work, the effect of residual stress on the isothermal tensile behavior of NiTi shape memory alloy is studied. The focused ion beam (FIB) and digital image correlation (DIC) are combined to measure the two-dimensional residual stress in nanocrystalline NiTi plates processed with prestrain laser shock peening. A four-point bending experiment is used to verify the accuracy of this measurement method. The results show that FIB-DIC method is an attractive tool for measuring the two-dimensional residual stress in nanocrystalline materials. It is shown that the internal residual stress can significantly reduce the phase transition stress, and the mechanism is studied via finite element and theoretical analyses. This work demonstrates that the mechanical behavior of NiTi shape memory alloys can be tailored via residual stress engineering.

Ion beam-induced heat damage in thermally low conductive specimens such as biological samples is gaining increased interest within the scientific community. This is partly due to the increased use of FIB-SEMs in biology as well as the development of complex materials, such as polymers, which need to be analyzed. The work presented here looks at the physics behind the ion beam–sample interactions and the effect of the incident ion energy (set by the acceleration voltage) on inducing increases in sample temperature and potential heat damage in thermally low conductive materials such as polymers and biological samples. The ion beam-induced heat for different ion beam currents at low acceleration voltages is calculated using Fourier’s law of heat transfer, finite element simulations, and numerical modelling results and compared to experiments. The results indicate that with lower accelerator voltages, higher ion beam currents in the nanoampere range can be used to pattern or image soft material and non-resin-embedded biological samples with increased milling speed but reduced heat damage.

Biological channels, especially membrane proteins, play a crucial role in metabolism, facilitating the transport of nutrients and other materials across cell membranes in a bio‐electrolyte environment. Artificial nanopores are employed to study ion and biomolecule transport behavior inside. While the non‐specific interaction between the nanopore surface and transport targets has garnered significant attention, the impact of surface roughness is overlooked. In this study, Nanopores with different levels of inner surface roughness is created by adjusting the FIB (Focus Ion Beam) fabrication parameters. Experiments and molecular dynamics (MD) simulations are employed to demonstrate that greater roughness results from larger FIB beam currents and shorter processing times. Lower roughness increases the capture rate of biomolecules, while greater roughness enhances the normalized blockade current (ΔI/I0). The phenomenon of rougher nanopores are attributed to a barrier‐dominated capture mechanism and more likely to induce DNA folding. This transport barrier exists in rough nanopores by utilizing steer molecular dynamics (SMD) simulations to investigate the force profile of a dA10 DNA molecule during translocation is demonstrated. This work illustrates how surface roughness influences the ionic current features and the translocation of biomolecules, paving a new way for tunning the molecule transport in nanopores. [ABSTRACT FROM AUTHOR]

The realization of perovskite oxide nanostructures with controlled shape and dimensions remains a challenge. Here, we investigate the use of helium and neon focused ion beam (FIB) milling in an ion microscope to fabricate BaTiO3 nanopillars of sub-500 nm in diameter starting from BaTiO3 (001) single crystals. Irradiation of BaTiO3 with He ions induces the formation of nanobubbles inside the material, eventually leading to surface swelling and blistering. Ne-FIB is shown to be suitable for milling without inducing surface swelling. The resulting structures are defect-free single crystal nanopillars, which are enveloped, on the top and lateral sidewalls, by a point defect-rich crystalline region and an outer Ne-rich amorphous layer. The amorphous layer can be selectively etched by dipping in diluted HF. The geometry and beam-induced damage of the milled nanopillars depend strongly on the patterning parameters and can be well controlled. Ne ion milling is shown to be an effective method to rapidly prototype BaTiO3 crystalline nanostructures. [ABSTRACT FROM AUTHOR]

We investigate the processes of microrelief formation on a Si(100) surface under irradiation with a Ga+-ion beam with an energy of 30 keV and a fluence of D = 1.25 × 1018–2 × 1019 cm–2 at incident angles of θ = 30°–85°. Within the angular range of θ = 40°–70°, a faceted wavy relief forms on the Si surface, while at θ = 30°, a sinusoidal relief develops. An experimental dependence of the periodic structure wavelength as a function of irradiation time λ(t) ~ t n, where n = 0.33–0.35, is obtained. The average values of relief propagation velocities and their direction relative to the incident ion direction are determined for θ = 30° and 40°, amounting to –5.3 ± 0.6 and –6.3 ± 0.6 nm s–1, respectively. The results are discussed in detail within the framework of existing models of wavelike surface relief formation under ion bombardment. [ABSTRACT FROM AUTHOR]

Superconducting quantum interference devices (SQUIDs) are directly sensitive to magnetic flux. Nano-fabricated SQUID chip with miniaturized superconducting circuits can be further utilized as scanning probes for imaging of materials. Scanning SQUID microscopy (SSM) combines both high spatial resolution and high magnetic field sensitivity and is especially suitable for studying low dimensional materials with small sensing volumes. Here, we briefly review the fabrication of different types of nano-SQUIDs and the recent progress of utilizing them for scanning microscopy of quantum materials. We focus on but are not limited to topological states, unconventional superconductivity and exotic magnetism with a particular interest in two-dimensional materials. The magnetometry, susceptometry and current imaging modes of the SSM coupled with the external tuning of the material by magnetic field, electrical field gating and strain reveals a multitude of information beyond the scopes of charge-sensing probes.

The evolution of a multilayer sample surface during focused ion beam processing was simulated using the level set method and experimentally studied by milling a silicon dioxide layer covering a crystalline silicon substrate. The simulation took into account the redeposition of atoms simultaneously sputtered from both layers of the sample as well as the influence of backscattered ions on the milling process. Monte Carlo simulations were applied to produce tabulated data on the angular distributions of sputtered atoms and backscattered ions.Two sets of test structures including narrow trenches and rectangular boxes with different aspect ratios were experimentally prepared, and their cross sections were visualized in scanning transmission electron microscopy images. The superimposition of the calculated structure profiles onto the images showed a satisfactory agreement between simulation and experimental results. In the case of boxes that were prepared with an asymmetric cross section, the simulation can accurately predict the depth and shape of the structures, but there is some inaccuracy in reproducing the form of the left sidewall of the structure with a large amount of the redeposited material.To further validate the developed simulation approach and gain a better understanding of the sputtering process, the distribution of oxygen atoms in the redeposited layer derived from the numerical data was compared with the corresponding elemental map acquired by energy-dispersive X-ray microanalysis.

Recent decades have witnessed a remarkable pace of innovation and performance improvements in integrated circuits (ICs), which have become indispensable in an array of critical applications ranging from military infrastructure to personal healthcare. Meanwhile, recent developments have brought physical security to the forefront of concern, particularly considering the valuable assets handled and stored within ICs. Among the various invasive attack vectors, micro-probing attacks have risen as a particularly menacing threat. These attacks leverage advanced focused ion beam (FIB) systems to enable post-silicon secret eavesdropping and circuit modifications with minimal traceability. As an evolved variant of micro-probing attacks, reroute attacks possess the ability to actively disable built-in shielding measures, granting access to the security-sensitive signals concealed beneath. To address and counter these emerging challenges, we introduce a layout-level framework known as Detour-RS. This framework is designed to automatically assess potential vulnerabilities, offering a systematic approach to identifying and mitigating exploitable weaknesses. Specifically, we employed a combination of linear and nonlinear programming-based approaches to identify the layout-aware attack costs in reroute attempts given specific target assets. The experimental results indicate that shielded designs outperform non-shielded structures against reroute attacks. Furthermore, among the two-layer shield configurations, the orthogonal layout exhibits better performance compared to the parallel arrangement. Furthermore, we explore both independent and dependent scenarios, where the latter accounts for potential interference among circuit edit locations. Notably, our results demonstrate a substantial near 50% increase in attack cost when employing the more realistic dependent estimation approach. In addition, we also propose time and gas consumption metrics to evaluate the resource consumption of the attackers, which provides a perspective for evaluating reroute attack efforts. We have collected the results for different categories of target assets and also the average resource consumption for each via, required during FIB reroute attack. [ABSTRACT FROM AUTHOR]

In recent years, the potential of porous soft materials in various device technologies has increased in importance due to applications in fields, such as wearable electronics, medicine, and transient devices. However, understanding the 3‐dimensional architecture of porous soft materials at the microscale remains a challenge. Herein, we present a method to structurally analyze soft materials using Focused Ion Beam – Scanning Electron Microscopy (FIB‐SEM) tomography. Two materials, polymethyl methacrylate (PMMA) membrane and pine wood veneer were chosen as test‐cases. FIB‐SEM was successfully used to reconstruct the true topography of these materials in 3D. Structural and physical properties were subsequently deduced from the rendered 3D models. The methodology used segmentation, coupled with optimized thresholding, image processing, and reconstruction protocols. The 3D models generated pore size distribution, pore inter‐connectivity, tortuosity, thickness, and curvature data. It was shown that FIB‐SEM tomography provides both an informative and visual depiction of structure. To evaluate and validate the FIB‐SEM reconstructions, porous properties were generated from the physical property analysis techniques, gas adsorption analysis using Brunauer‐Emmett‐Teller (BET) surface area analysis and mercury intrusion porosimetry (MIP) analysis. In general, the data obtained from the FIB‐SEM reconstructions was well‐matched with the physical data. Research Highlights: Porous specimens of both synthetic and biological nature, a poly(methyl methacrylate) membrane and a pine veneer respectively, are reconstructed via FIB‐SEM tomography without resin‐embedding.Different thresholding and reconstruction methods are explored whereby shadowing artifacts are present with the aid of free open‐source software.Reconstruction data is compared to physical data: MIP, gas adsorption isotherms which are analyzed via BET and Barrett‐Joyner‐Halenda (BJH) analysis to yield a full picture of the materials. [ABSTRACT FROM AUTHOR]

This study explores the microstructural characteristics of gadolinium (Gd)-rich phases in titanium (Ti) alloys through comprehensive electron microscopy analysis. The Ti alloys were produced using plasma arc melting and subsequently hot-forged. Elaborate material characterization, including scanning electron microscopy, electron backscatter diffraction, and energy dispersive spectroscopy, revealed the formation of round or angular Gd oxides and elongated Gd-rich grains within the alloy. High-magnification transmission electron microscopy and X-ray diffraction confirmed the presence of the FCC-type γ-Gd phase, influenced by the oxygen intake during casting, coexisting with Gd2O3 due to their similar crystal structures. The study also observed internal twins in the Gd grains, potentially delaying the transformation to the stable α-Gd phase. The significant mechanical property differences between the Gd-rich phases and the Ti matrix caused defects at phase interfaces during hot processing, weakening the Gd phase. This work enhances the understanding of Gd phase formation and its implications on the mechanical properties of Ti–Gd alloys.

This article presents an examination of well-controlled patterns created using a Ga+-based focused ion beam (FIB) on glass, while silicon substrates were used to evaluate the FIB performance by its achievable feature size versus time constraints. The pattern creation on glass was developed with the aim of studying potential surface-enhanced Raman spectroscopy (SERS) applications. Furthermore, the FIB was used to create dimer systems of periodically and randomly positioned dumbbell-shaped pits on the glass (each dimer occupies an area of 203 × 87 nm2). By following the bitmap pattern files, the FIB ensured there was 3000 dimer fabrication over a 20 × 20 μm2 large area, with a pit size and position variation below 10 nm. The article highlights that FIB can be used for precise large-area nano-fabrication. The gold nanoparticle dimers were formed on the prepatterned surface via capillary force-assisted deposition. The fabricated nanostructures were tested in SERS measurements. The enhancement factor for Rhodamine B molecule reached ~105, demonstrating the potential application of the method to create nanostructures in the sensor domain.

In recent years, the field of micro- and nanochannel fabrication has seen significant advancements driven by the need for precision in biomedical, environmental, and industrial applications. This review provides a comprehensive analysis of emerging fabrication technologies, including photolithography, soft lithography, 3D printing, electron-beam lithography (EBL), wet/dry etching, injection molding, focused ion beam (FIB) milling, laser micromachining, and micro-milling. Each of these methods offers unique advantages in terms of scalability, precision, and cost-effectiveness, enabling the creation of highly customized micro- and nanochannel structures. Challenges related to scalability, resolution, and the high cost of traditional techniques are addressed through innovations such as deep reactive ion etching (DRIE) and multipass micro-milling. This paper also explores the application potential of these technologies in areas such as lab-on-a-chip devices, biomedical diagnostics, and energy-efficient cooling systems. With continued research and technological refinement, these methods are poised to significantly impact the future of microfluidic and nanofluidic systems.

Although in situ transmission electron microscopy (TEM) of nanomaterials has been gaining importance in recent years, difficulties in sample preparation have limited the number of studies on electrical properties. Here, a support‐based preparation method of individual 1D and 2D materials is presented, which yields a reproducible sample transfer for electrical investigation by in situ TEM. A mechanically rigid support grid facilitates the transfer and contacting to in situ chips by focused ion beam with minimum damage and contamination. The transfer quality is assessed by exemplary specimens of different nanomaterials, including a monolayer of WS2. Possible studies concern the interplay between structural properties and electrical characteristics on the individual nanomaterial level as well as failure analysis under electrical current or studies of electromigration, Joule heating, and related effects. The TEM measurements can be enriched by additional correlative microscopy and spectroscopy carried out on the identical object with techniques that allow a characterization with a spatial resolution in the range of a few microns. Although developed for in situ TEM, the present transfer method is also applicable to transferring nanomaterials to similar chips for performing further studies or even for using them in potential electrical/optoelectronic/sensing devices. [ABSTRACT FROM AUTHOR]

Through its capability for 3D mapping of Li at the nanoscale, atom probe tomography (APT) is poised to play a key role in understanding the microstructural degradation of lithium‐ion batteries (LIB) during successive charge‐ and discharge cycles. However, APT application to materials for LIB is plagued by the field induced delithiation (deintercalation) of Li‐ions during the analysis itself that prevents the precise assessment of the Li distribution. Here, we showcase how a thin Cr‐coating, in‐situ formed on APT specimens of NMC811 in the focused‐ion beam (FIB), preserves the sample's integrity and circumvent this deleterious delithiation. Cr‐coated specimens demonstrated remarkable improvements in data quality and virtually eliminated premature specimen failures, allowing for more precise measurements via. improved statistics. Through improved data analysis, we reveal substantial cation fluctuations in commercial grade NMC811, including complete grains of LiMnO. The current methodology stands out for its simplicity and cost‐effectiveness and is a viable approach to prepare battery cathodes and anodes for systematic APT studies. [ABSTRACT FROM AUTHOR]

The deformation behavior of single crystals of manganese pillars generated by focused ion beam (FIB), with diameters ranging from -1 μm to -4.5 μm, has been studied as a function of specimen size using micropillar compression at ambient temperature. The manganese pillars were machined from randomly chosen larger grains of polycrystalline metal. At ambient temperature, single crystals of manganese display chaotic slip planes emerging on the sample surface and brittle plastic deformation when the sample size is decreased to the micrometer scale. The manganese pillars reached very high f low stresses in the range of 4-5.6 GPa. The stress-strain curves of all tested manganese pillars demonstrated significant work hardening and smooth f low behavior, with strains up to 8-10%. After 10% strain, however, the f low stresses remained constant with no work hardening. As previously reported, the manganese pillars with undetermined crystal orientation demonstrated a less pronounced size effect (-0.14) by the size effect exponent of BCC pillars. [ABSTRACT FROM AUTHOR]

This work reports on the investigation of homogeneity of the inside of indium micro-bumps/columns placed on Ti/Pt/Au under bump metallisation. This is very important for connection resistivity, long-time durability, and subsequent hybridisation process (e.g., die-bonding). Gold reacts with indium to form intermetallic alloys with different chemo-physical parameters than pure indium. The geometrical and structural parameters of intermetallic alloys were analysed based on transmission electron microscope images. Distribution of elements in the investigated samples was determined using the transmission electron microscope with energy dispersive spectroscopy method. A thickness of intermetallic alloy was 1.02 µm and 1.67 µm in non-annealed (A) and annealed (B) indium columns, respectively. The layered and column-like interior structure of alloys was observed for both samples, respectively, with twice bigger grains in sample B. The graded chemical composition of Au-In intermetallic alloy was detected for the non-annealed In columns in contrast to the constant composition of 40% of Au and 60% of In for the annealed sample B. The atomic distribution has a minor impact on the In column mechanical stability. A yield above 99% of an In column with a 25 µm diameter and a 11 µm height is possible for a uniform columnar structure of intermetallic alloy with a thickness of 1.67 µm. [ABSTRACT FROM AUTHOR]

Focused ion beam (FIB) has become a powerful tool for transmission electron microscopy sample preparation in the nanoelectronics industry and has in recent years also shown its benefits for specific preparation steps in electrical scanning probe microscopy (SPM). Most recently, a novel SPM approach – so-called reverse tip sample (RTS) SPM – has been proposed in which the position of sample and tip are switched compared to standard SPM; in RTS SPM the sample is attached to the end of a cantilever beam. To achieve this configuration, the region of interest must first be extracted from a substrate and then needs to be reliably fixed to the cantilever by FIB. Therefore, we have explored and developed dedicated FIB preparation methods for RTS SPM in this work. Our established procedures ensure a strong mechanical and good electrical connection of the sample to the cantilever for both cross-section and top view sample preparation. Furthermore, we introduce an approach for mounting samples from a full wafer size workflow. This paper presents the developed FIB procedures and discusses the quality and stability of all mounted samples and their electrical evaluation in RTS SPM.

Mechanical size effects are a well known phenomenon when the sample volume is reduced or the characteristic length of the microstructure is changed. While size effects in micropillar compression (smaller is stronger) or due to grain refinement (Hall-Petch) are well understood, this is less so in fracture mechanics. Given this lack of knowledge, the main question addressed in this work is: What happens to the fatigue crack growth properties when extrinsic size effects play a role? To answer this question, nanocrystalline nickel cantilevers, ranging in width from 5 to Image 1, were subjected to fatigue crack growth. The crack growth rates and stress intensity factors were calculated and the Paris exponent in the stable crack growth regime was determined. It was found that the results scatter more strongly for the smaller cantilevers compared to the larger cantilevers. Results are interpreted in terms of plastic zone size and ligament size which are found to be critical for small cantilevers.

V-Cr-Ti alloys with reduced Ti contents are expected to be good candidates as recyclable structural materials for fusion reactors. Herein, He irradiation was applied to V-4Cr-xTi (x = 0 to 4) alloys to investigate the additional effect of Ti and gas interstitial impurities on their microstructural evolution and irradiation hardening. Following He irradiation of the specimens at 700 °C with a maximum damage depth of 0.5 dpa, transmission electron microscopy and nanoindentation hardness tests were conducted. The microstructural evolution of the titanium-oxycarbonitride (Ti(CON)) precipitates formed during He ion irradiation was observed. The behavior of irradiation hardening is explained by the formation process of Ti(CON) precipitates and the magnitude of irradiation hardening depends on the amount of gas interstitial impurities that contribute to precipitate formation.

Wearable and implantable microscale electronic sensors have been developed for a range of biomedical applications. The sensors, typically millimeter size silicon microchips, are sought for multiple sensing functions but are severely constrained by size and power. To address these challenges, a hardware programmable application‐specific integrated circuit design is proposed and post‐process methodology is exemplified by the design of battery‐less wireless microchips. Specifically, both mixed‐signal and radio frequency circuits are designed by incorporating metal fuses and anti‐fuses on the top metal layer to enable programmability of any number of features in hardware of the system‐on‐chip (SoC) designs. This is accomplished in post‐foundry editing by combining laser ablation and focused ion beam processing. The programmability provided by the technique can significantly accelerate the SoC chip development process by enabling the exploration of multiple internal circuit parameters without the requirement of additional programming pads or extra power consumption. As examples, experimental results are described for sub‐millimeter size complementary metal‐oxide‐semiconductor microchips being developed for wireless electroencephalogram sensors and as implantable microstimulators for neural interfaces. The editing technique can be broadly applicable for miniaturized biomedical wearables and implants, opening up new possibilities for their expedited development and adoption in the field of smart healthcare. [ABSTRACT FROM AUTHOR]

We studied the influence of the focused ion beam milling of ridge waveguides on lasing parameters of edge-emitting lasers, based on a separate confinement double heterostructure. It is shown that there are three degrees of influence, according to the etching depth: modification of the waveguide properties only, a decrease in efficiency without changing the threshold current, and a simultaneous deterioration in the threshold current and efficiency with significant modification of the optical characteristics of the laser. [ABSTRACT FROM AUTHOR]

Focused ion beam (FIB) machining can be used to fabricate gallium arsenide-based devices, which have a surface finish of several nanometers, and the FIB machining speed and surface finish can be greatly improved using xenon difluoride (XeF2) gas-assisted etching. Although the refresh time is one of the most important parameters in the gas-assisted etching process, its effect on the machining quality of the surface finish has rarely been studied. Therefore, in this work, we investigated the effect of the refresh time on the etching process, including the dissociation process of XeF2, the refresh time dependency of the sputter in yield under different incident angles, and the surface finish under different refresh times. The results revealed that a selective etching mechanism occurred at different refresh times. At an incidence angle of 0°, the sputtering yield increased with the refresh time and reached its maximum value at 500 ms; at an incidence angle of 30°, the sputtering yield reached its minimum value at a refresh time of 500 ms. For surface roughness, the incident angle played a more important role than the refresh time. The surface finish was slightly better at an incidence angle of 30° than at 0°. In addition, both F and Xe elements were detected in the processed area: Xe elements were evenly distributed throughout the processing area, while F elements tended to accumulate in the whole processing area. The results suggest that the optimum surface can be obtained when a larger refresh time is employed.Highlights: The sputtering yield varies with refreshing time under different incidence angle conditions due to the difference in material removal rate. The effect of varying refresh time on machined surface roughness is approximated under the same incidence angle. In all refresh time conditions, the F elements are concentrated in the processed area, while the Xe elements are evenly distributed across the entire surface. [ABSTRACT FROM AUTHOR]

The success of titanium dental implants relies on osseointegration, the load‐bearing connection between bone tissue and the device that, in contact osteogenesis, comprises the deposition of bony cement line matrix onto the implant surface. Titanium dioxide nanotubes (NTs) are considered a promising surface for improved osseointegration, yet the mechanisms of cement line integration with such features remains elusive. Herein, we illustrate cement line deposition into NTs on the surface of titanium implants with two underlaying microstructures: a machined surface or a blasted/acid etched surface placed in the tibiae of Wistar rats. After retrieval, scanning electron microscopy of tissue reflected from the implant surface indicated minimal incursion of the cement line matrix into the NTs. To investigate this further, focused ion beam was utilized to prepare cross‐sectional samples that could be characterized using scanning transmission electron microscopy. The cement line matrix covered NTs regardless of underlying microstructure, which was further confirmed by elemental analysis. In some instances, cement line infiltration into the NTs was noted, which reveals a mechanism of nanoscale anchorage. This study is the first to demonstrate cement line deposition into titanium NTs, suggesting nano‐anchorage as a mechanism for the success of the NT modified surfaces in vivo. [ABSTRACT FROM AUTHOR]

The ability to spatially control and modify material properties on the nanoscale, including within nanoscale objects themselves, is a fundamental requirement for the development of advanced nanotechnologies. The development of a platform for nanoscale advanced materials engineering (P-NAME) designed to meet this demand is demonstrated. P-NAME delivers a high-resolution focused ion beam system with a coincident scanning electron microscope and secondary electron detection of single-ion implantation events. The isotopic mass-resolution capability of the P-NAME system for a wide range of ion species is demonstrated, offering access to the implantation of isotopes that are vital for nanomaterials engineering and nanofunctionalization. The performance of the isotopic mass selection is independently validated using secondary ion mass spectrometry (SIMS) for a number of species implanted into intrinsic silicon. The SIMS results are shown to be in good agreement with dynamic ion implantation simulations, demonstrating the validity of this simulation approach. The wider performance capabilities of P-NAME, including sub-10 nm ion beam imaging resolution and the ability to perform direct-write ion beam doping and nanoscale ion lithography, are also demonstrated. [ABSTRACT FROM AUTHOR]

We reveal a novel phenomenon observed after self-catalytic growth of GaAs nanowires (NWs) on Si(111) substrates treated with a Ga focused ion beam (FIB). Depending on the ion dose, NW arrays with various geometrical parameters can be obtained. A minor treatment of the substrate enables a slight increase in the surface density of NWs relative to an unmodified substrate area. As the ion dose is increased up to ∼0.1 pC μ m−2, the growth of GaAs NWs and nanocrystals is suppressed. However, a further increase in the ion dose stimulates the crystal growth leading to the formation of extremely thin NWs (39 ± 5 nm) with a remarkably high surface density of up to 15 μ m−2. Resting upon an analysis of the surface structure before and after stages of ion-beam treatment, ultra-high vacuum annealing and NW growth, we propose a mechanism underlying the phenomenon observed. We assume that the chemical interaction between embedded Ga ions and a native Si oxide layer leads either to the enhancement of the passivation properties of the oxide layer within FIB-modified areas (at low and middle ion doses), or to the etching of the passivating oxide layer by excess Ga atoms, resulting in the formation of pores (at high ion doses). Due to this behavior, local fabrication of GaAs NW arrays with a diverse range of characteristics can be implemented on the same substrate. This approach opens a new way for self-catalytic growth of GaAs NWs. [ABSTRACT FROM AUTHOR]

The milling profiles of single-crystal gallium nitride (GaN) when subjected to focused ion beams (FIBs) using gallium (Ga), xenon (Xe), and helium (He) ion sources were investigated. An experimental analysis via annular dark-field scanning transmission electron microscopy (ADF-STEM) and high-resolution transmission electron microscopy (HRTEM) revealed that Ga-FIB milling yields trenches with higher aspect ratios compared to Xe-FIB milling for the selected ion beam parameters (30 kV, 42 pA), while He-FIB induces local lattice disorder. Molecular dynamics (MD) simulations were employed to investigate the milling process, confirming that probe size critically influences trench aspect ratios. Interestingly, the MD simulations also showed that Xe-FIB generates higher aspect ratios than Ga-FIB with the same probe size, indicating that Xe-FIB could also be an effective option for nanoscale patterning. Atomic defects such as vacancies and interstitials in GaN from He-FIB milling were suggested by the MD simulations, supporting the lattice disorder observed via HRTEM. This combined experimental and simulation approach has enhanced our understanding of FIB milling dynamics and will benefit the fabrication of nanostructures via the FIB technique. [ABSTRACT FROM AUTHOR]

Metal oxide semiconductor (MOS) gas sensors are widely used for gas detection. Typically, the hotplate element is the key component in MOS gas sensors which provide a proper and tunable operation temperature. However, the low power efficiency of the standard hotplates greatly limits the portable application of MOS gas sensors. The miniaturization of the hotplate geometry is one of the most effective methods used to reduce its power consumption. In this work, a new method is presented, combining electron beam lithography (EBL) and focused ion beam (FIB) technologies to obtain low power consumption. EBL is used to define the low-resolution section of the electrode, and FIB technology is utilized to pattern the high-resolution part. Different Au++ ion fluences in FIBs are tested in different milling strategies. The resulting devices are characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and secondary ion mass spectrometry (SIMS). Furthermore, the electrical resistance of the hotplate is measured at different voltages, and the operational temperature is calculated based on the Pt temperature coefficient of resistance value. In addition, the thermal heater and electrical stability is studied at different temperatures for 110 h. Finally, the implementation of the fabricated hotplate in ZnO gas sensors is investigated using ethanol at 250 °C. [ABSTRACT FROM AUTHOR]

Ion implantation is a key capability for the semiconductor industry. As devices shrink, novel materials enter the manufacturing line, and quantum technologies transition to being more mainstream. Traditional implantation methods fall short in terms of energy, ion species, and positional precision. Here, we demonstrate 1 keV focused ion beam Au implantation into Si and validate the results via atom probe tomography. We show the Au implant depth at 1 keV is 0.8 nm and that identical results for low-energy ion implants can be achieved by either lowering the column voltage or decelerating ions using bias while maintaining a sub-micron beam focus. We compare our experimental results to static calculations using SRIM and dynamic calculations using binary collision approximation codes TRIDYN and IMSIL. A large discrepancy between the static and dynamic simulation is found, which is due to lattice enrichment with high-stopping-power Au and surface sputtering. Additionally, we demonstrate how model details are particularly important to the simulation of these low-energy heavy-ion implantations. Finally, we discuss how our results pave a way towards much lower implantation energies while maintaining high spatial resolution. [ABSTRACT FROM AUTHOR]

Abstract: A method for small-scale testing and imaging of freestanding, microtomed polymer films using a push-to-pull device is presented. Central to this method was the development of a sample preparation technique which utilized solvents at cryogenic temperatures to transfer and deposit delicate thin films onto the microfabricated push-to-pull devices. The preparation of focused ion beam (FIB)-milled tensile specimens enabled quantitative in situ TEM tensile testing, but artifacts associated with ion and electron beam irradiation motivated the development of a FIB-free specimen preparation method. The FIB-free method was enabled by the design and fabrication of oversized strain-locking push-to-pull devices. An adaptation for push-to-pull devices to be compatible with an instrumented nanoindenter expanded the testing capabilities to include in situ heating. These innovations provided quantitative mechanical testing, postmortem TEM imaging, and the ability to measure the glass transition temperature, via dynamic mechanical analysis, of freestanding polymer films. Results for each of these mentioned characterization methods are presented and discussed in terms of polymer nanomechanics. Graphic Abstract: [Figure not available: see fulltext.]

Abstract: A method for small-scale testing and imaging of freestanding, microtomed polymer films using a push-to-pull device is presented. Central to this method was the development of a sample preparation technique which utilized solvents at cryogenic temperatures to transfer and deposit delicate thin films onto the microfabricated push-to-pull devices. The preparation of focused ion beam (FIB)-milled tensile specimens enabled quantitative in situ TEM tensile testing, but artifacts associated with ion and electron beam irradiation motivated the development of a FIB-free specimen preparation method. The FIB-free method was enabled by the design and fabrication of oversized strain-locking push-to-pull devices. An adaptation for push-to-pull devices to be compatible with an instrumented nanoindenter expanded the testing capabilities to include in situ heating. These innovations provided quantitative mechanical testing, postmortem TEM imaging, and the ability to measure the glass transition temperature, via dynamic mechanical analysis, of freestanding polymer films. Results for each of these mentioned characterization methods are presented and discussed in terms of polymer nanomechanics. Graphic Abstract: [Figure not available: see fulltext.]

Recent decades have witnessed a remarkable pace of innovation and performance improvements in integrated circuits (ICs), which have become indispensable in an array of critical applications ranging from military infrastructure to personal healthcare. Meanwhile, recent developments have brought physical security to the forefront of concern, particularly considering the valuable assets handled and stored within ICs. Among the various invasive attack vectors, micro-probing attacks have risen as a particularly menacing threat. These attacks leverage advanced focused ion beam (FIB) systems to enable post-silicon secret eavesdropping and circuit modifications with minimal traceability. As an evolved variant of micro-probing attacks, reroute attacks possess the ability to actively disable built-in shielding measures, granting access to the security-sensitive signals concealed beneath. To address and counter these emerging challenges, we introduce a layout-level framework known as Detour-RS. This framework is designed to automatically assess potential vulnerabilities, offering a systematic approach to identifying and mitigating exploitable weaknesses. Specifically, we employed a combination of linear and nonlinear programming-based approaches to identify the layout-aware attack costs in reroute attempts given specific target assets. The experimental results indicate that shielded designs outperform non-shielded structures against reroute attacks. Furthermore, among the two-layer shield configurations, the orthogonal layout exhibits better performance compared to the parallel arrangement. Furthermore, we explore both independent and dependent scenarios, where the latter accounts for potential interference among circuit edit locations. Notably, our results demonstrate a substantial near 50% increase in attack cost when employing the more realistic dependent estimation approach. In addition, we also propose time and gas consumption metrics to evaluate the resource consumption of the attackers, which provides a perspective for evaluating reroute attack efforts. We have collected the results for different categories of target assets and also the average resource consumption for each via, required during FIB reroute attack.

Abstract Wearable and implantable microscale electronic sensors have been developed for a range of biomedical applications. The sensors, typically millimeter size silicon microchips, are sought for multiple sensing functions but are severely constrained by size and power. To address these challenges, a hardware programmable application‐specific integrated circuit design is proposed and post‐process methodology is exemplified by the design of battery‐less wireless microchips. Specifically, both mixed‐signal and radio frequency circuits are designed by incorporating metal fuses and anti‐fuses on the top metal layer to enable programmability of any number of features in hardware of the system‐on‐chip (SoC) designs. This is accomplished in post‐foundry editing by combining laser ablation and focused ion beam processing. The programmability provided by the technique can significantly accelerate the SoC chip development process by enabling the exploration of multiple internal circuit parameters without the requirement of additional programming pads or extra power consumption. As examples, experimental results are described for sub‐millimeter size complementary metal‐oxide‐semiconductor microchips being developed for wireless electroencephalogram sensors and as implantable microstimulators for neural interfaces. The editing technique can be broadly applicable for miniaturized biomedical wearables and implants, opening up new possibilities for their expedited development and adoption in the field of smart healthcare.

Zinc oxide (ZnO) nanorod arrays have a wide range of applications. Controlling the position of the seed layers (ZnO films) and the nanorod morphology plays an essential role in the fabrication of the sensors and the fulfilment of specific sensing properties, while the patterning of seed layers and controlling the NR morphology have mostly been studied separately. In this study, a focused ion beam was employed to decompose spin-coated zinc acetate films for the precise positioning of the seed layers. The resulting ZnO films were used to hydrothermally grow vertical ZnO NRs that process a high responsivity of 1.24 × 106 A/W at a bias voltage of 5 V. Moreover, this approach provides the following advantages: (1) the carbon to zinc ratio of the zinc acetate film decreased from 4:1 to 1:18.9 after irradiation, demonstrating the efficient decomposition; (2) a patterned ZnO film can be obtained with a low irradiation dose of 1000 μC/cm2; and (3) the seed layer can be utilized directly for vertical nanorod growth without annealing. The morphology of NRs is characterized, and the nanorods grown on seed layers under different treatment conditions had different X-ray diffraction (XRD) peak patterns. Furthermore, the UV–vis absorption spectra of the nanorods were measured. Finally, we examined the rapid patterning of the ZnO thin films. We propose a simple and efficient approach for the decomposition of zinc acetate into patterned ZnO; this provides an integrated solution for ZnO film positioning and the vertical growth of ZnO NRs, which could also offer an approach and inspiration for ultraviolet (UV) detection and ideas for the localized growth of other ZnO nanomaterials. [ABSTRACT FROM AUTHOR]

In situ TEM mechanical stages based on micro-electromechanical systems (MEMS) have developed rapidly over recent decades. However, image-based quantification of MEMS mechanical stages suffers from the trade-off between spatial and temporal resolutions. Here, by taking in situ TEM nanoindentation as an example, we developed a novel method for image-based quantified in situ TEM mechanical tests with both high spatial and temporal resolutions. A reference beam was introduced to the close vicinity of the indenter–sample region. By arranging the indenter, the sample, and the reference beam in a micron-sized area, the indentation depth and load can be directly and dynamically acquired from the relative motion of markers on the three components, while observing the indentation process at a relatively high magnification. No alteration of viewing area is involved throughout the process. Therefore, no deformation events will be missed, and the collection rate of quantification data can be raised significantly. [ABSTRACT FROM AUTHOR]

Organic—inorganic hybrid perovskites have attracted considerable attention for developing novel optoelectronic devices owing to their excellent photoresponses. However, conventional nanolithography of hybrid perovskites remains a challenge because they undergo severe damage in standard lithographic solvents, which prohibits device miniaturization and integration. In this study, a novel transparent stencil nanolithography (t‐SL) technique is developed based on focused ion beam (FIB)‐assisted polyethylene terephthalate (PET) direct patterning. The proposed t‐SL enables ultrahigh lithography resolution down to 100 nm and accurate stencil mask alignment. Moreover, the stencil mask can be reused more than ten times, which is cost‐effective for device fabrication. By applying this lithographic technique to hybrid perovskites, a high‐performance 2D hybrid perovskite heterostructure photodetector is fabricated. The responsivity and detectivity of the proposed heterostructure photodetector can reach up to 28.3 A W−1 and 1.5 × 1013 Jones, respectively. This t‐SL nanolithography technique based on FIB‐assisted PET direct patterning can effectively support the miniaturization and integration of hybrid‐perovskite‐based electronic devices. [ABSTRACT FROM AUTHOR]

Recent technical advances in the detection of backscattered electrons during scanning electron microscopy (SEM) have improved resolution and have provided several new technologies for research and clinical practice in kidney disease. The advances include three-dimensional (3D) electron microscopy (3D-EM), correlative light and electron microscopy (CLEM), low-vacuum SEM (LVSEM), and scanning transmission electron microscopy (STEM). 3D-EM analysis used to be laborious, but recently three different technologies, serial block-face SEM, focused ion beam SEM, and array tomography, have made 3D-EM easier by automating sectioning and the subsequent image acquisition in an SEM. CLEM is a method to correlate light microscopic images, especially immunofluorescent and electron microscopy images, providing detailed ultrastructure of the area of interest where the immunofluorescent marker is located. LVSEM enables the use of SEM on materials with poor electron conductivity. For example, LVSEM makes it possible for high resolution, 3D observation of paraffin sections. Finally, STEM is a method to observe ultrathin sections with improved resolution by using the focused electron beam scanning used in SEM and not the broad electron beam used in transmission electron microscopy. These technical advances in electron microscopy are promising to provide plenty of novel insights for understanding the pathogenesis and diagnosis of various glomerular diseases.