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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]

The present work focuses on the shrinkage of PMMA films under irradiation and its application to the creation of optical devices. We prepared the free-standing PMMA films in four different thicknesses (13, 21, 32, and 43 μm), and PMMA films of the same thickness, but deposited on a glass substrate. A diffraction grating was chosen as the optical device to show the applicability of the method. The study revealed that at a film thickness of 13–32 μm, the shrinkage of the free-standing film increases proportionally to its thickness, while the film on the substrate does not have a pronounced dependence. Films with the thickness of 43 µm do not follow this trend. It was found that under the same irradiation conditions, the film on the substrate shrinks more compared to the free-standing film. Interference patterns from the created diffraction gratings were shown to present spurious illumination areas. [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.

The most significant goal of nanophotonics is the development of high-speed quantum emitting devices operating at ambient temperature. In this regard, plasmonic nanoparticles-on-mirror are potential candidates for designing high-speed photon sources. We introduce a novel hybrid nanoantenna (HNA) with CdSe/CdS colloidal quantum dots (QDs) based on a silver nanocube in a metal cup that presents a nanoparticle-in-cavity coupled with an emitters system. We use focused ion beam nanolithography to fabricate an ordered array of cups, which were then filled with colloidal nanoparticles using the most simple drop-casting and spin coating methods. The spectral and time-resolved studies of the samples with one or more nanocubes in the cup reveal a significant change in the radiation characteristics of QDs inside the nanoantenna. The Purcell effect causes an increase in the fluorescence decay rate (≥30) and an increase in the fluorescence intensity (≥3) of emitters in the HNA. Using the finite element method simulations, we have discovered that the proximity of the cups wall affects the oscillation modes of the gap plasmon, which, in turn, leads to changes in the electric field enhancement inside the nanoantenna gap. Additionally, substantial variations in the behavior of the gap plasmons at different polarizations of the exciting radiation have been revealed. The proposed nanoantenna can be useful in the development of plasmonic sensors, display pixels, and single-photon sources. [ABSTRACT FROM AUTHOR]

Optical and electrooptical properties of a system consisting of subwavelength metal gratings and nematic liquid crystal layer are studied. Aluminium gratings that also act as interdigitated electrodes are produced by focused ion beam lithography. It is found that a liquid crystal layer strongly influences both the resonance and light polarization properties characteristic of the gratings. Enhanced transmittance is observed not only for the TM-polarized light in the near infrared spectral range but also for the TE-polarized light in the visible range. Although the electrodes are separated by nanosized slits, and the electric field is strongly localized near the surface, a pronounced electrooptical effect is registered. The effect is explained in terms of local reorientation of liquid crystal molecules at the grating surface and propagation of the orientational deformation from the surface into the bulk of the liquid crystal layer. [ABSTRACT FROM AUTHOR]

The feature of the promising tool of lithographic nanostructuring based on selective exposure of polymer resist by ion beam is very compact (of about tens of nanometers) beam interaction volume. Herewith the main part of beam energy is deposited in the resist and is spent to its modification. It causes the set of advantages specific for this method: sub-10 nanometer resolution achievable, very high energy efficiency and almost complete absence of proximity effect. But also due to this feature absorbed doze essentially inhomogeneous in resist and the dissolution rate is strongly dependent on depth. So the common procedure of resist contrast determination cannot be applied anymore. In the present work a new method for resist contrast determination considering the relation between dissolution rate and deposited energy density is suggested and realized. By using it for PMMA resist irradiated by 30 keV Ga+ ion beam the value of contrast was determined to be 3.1 and ions energy length was estimated to be 42 nm. [ABSTRACT FROM AUTHOR]

3D microstructures in pure poly(dimethylsiloxane) (PDMS) and PDMS with embedded Au nanoparticles were prepared by ion beam lithography without any further etching. Two mega‐electron volts helium and 10 MeV oxygen ions were used for ion microstructuring. Parallel lines of 1 mm in length and 10 μm in thickness were fabricated for investigation of the effect of the nanoparticles presence in the polymer on the surface morphology of the created microstructures. The created microstructures were checked by optical microscope. Infrared (IR) spectrometry was used to study the effect of the ions type and fluence on the chemical changes of the material. Atomic force microscopy was used for the fine detail study as well as for checking the microstructure quality. Analysis revealed an increased radiation resistance of the nanocomposite compared to the pure PDMS. Shrinkage is proportional to the fluence, but the maximum value for both materials is limited by saturation. 3D microstructure in modified PDMS obtained at the same irradiation condition as pure PDMS is characterized by its smaller height. Obtaining the microstructure in nanocomposite of the same height as in pure PDMS by increasing the fluence can be impossible due to saturation of shrinkage and/or radiation‐induced heating of the material. [ABSTRACT FROM AUTHOR]

We report on nanoscale patterning of GaAs (100) semiconductor substrates employing an ion projection through a self-organized stencil mask. The nanostructured mask, formed by ion beam sputtering of a polycrystalline Au film, allows driving the GaAs morphology strongly out of equilibrium. In a second stage, after the stencil mask is removed, we quantitatively follow the dynamical evolution of the forced system toward equilibrium by analyzing the evolution of the power spectral density of the height profiles and their slope and curvature distribution. Strong differences are observed by comparing the relaxation dynamics of GaAs surfaces which tend to smoothen with that of glass, a material which instead tends to non-linearly amplify the pattern once driven out of equilibrium by the stencil mask. [ABSTRACT FROM AUTHOR]

We demonstrate a novel approach for the easy fabrication of photonic crystals (PCs) with arbitrary optical lattice using two-photon holographic lithography (HL). The quadratic dependence of the two-photon absorption process dramatically increases the contrast of the pattern and the low absorption coefficient of the photoresist at 720 nm lead to a high aspect ratio and low fluctuation of the pattern. By applying such a technique, defect-free and highly uniform one-dimensional gratings, two-dimensional quasicrystals, and three-dimensional (3D) face center cube-type PCs of high aspect ratio and small filling factor are obtained. This two-photon based HL technique is particularly suitable for making 3D PCs and quasicrystals with complex and fine structural details. [ABSTRACT FROM AUTHOR]

The optical properties of InGaN/GaN quantum wells, which were nanopatterned into cylindrical shapes with diameters of 2 μm, 1 μm, or 500 nm by chemically assisted ion beam etching, were investigated. Photoluminescence (PL) and time-resolved PL measurements suggest inhomogeneous relaxation of the lattice-mismatch induced strain in the InGaN layers. By comparing to a strain distribution simulation, we found that partial stain relaxation occurs at the free side wall, but strain remains in the middle of the pillar structures. The strain relaxation leads to an enhanced radiative recombination rate by a factor of 4–8. On the other hand, nonradiative recombination processes are not strongly affected, even by postgrowth etching. Those characteristics are clearly reflected in the doughnut-shape emission patterns observed by optical microscopy. [ABSTRACT FROM AUTHOR]

Resistive switching memory cells with polycrystalline (AgI)0.2(Ag2MoO4)0.8 (AIMO) solid electrolyte films as storage medium were fabricated on SiO2/Pt/Ti/Si substrates by using pulse laser deposition technique and focused ion beam lithography. X-ray diffraction, scanning electron microscopy, and energy dispersive x-ray analysis have been employed to investigate the structure, the surface morphology, and the composition of AIMO thin films. The Ag/AIMO/Pt memory cells with sandwich structure exhibit stable, reproducible, and reliable resistive switching characteristics. The ratio of resistance between high resistance states and low resistance states can reach ∼105. Moreover, the low resistance is ∼500 Ω at a compliance current of 0.5 mA, which is favorable to reduce the power dissipation of the entire circuit. The switching-on mechanism has been discussed and the metallic conduction characteristic has also been verified. The fast response speed and the good retention properties further indicate that polycrystalline AIMO thin film is a potential candidate for the next generation nonvolatile memory. [ABSTRACT FROM AUTHOR]

We present a straightforward method for fabrication of patterns of metallic nanostructures. The focused ion beam (FIB) lithography has been used to locally modify a native SiO2 layer on a silicon substrate. On the modified areas preferential nucleation of cobalt islands is observed. The cobalt islands formed upon deposition at 400–430 °C combined with an intermediate annealing at 550 °C have a uniform size distribution and their size can be controlled by the distance between the nucleation sites and the amount of deposited material. It is proposed that the island formation at patterned sites is due to reduced surface diffusion of Co atoms in the vicinity of FIB modified areas. The intermediate annealing improves the island morphology since the kinetic diffusion limits are lowered and system reconfigures toward its equilibrium state. [ABSTRACT FROM AUTHOR]

The reactions of Con+ (n=1–18) with N2 are measured as a function of kinetic energy over a range of 0–15 eV in a guided ion beam tandem mass spectrometer. A variety of Com+, ComN+, and ComN2+ (m≤=n) product ions are observed, all in endothermic processes, with collision-induced dissociation dominating the products for all clusters. Bond dissociation energies for both cobalt cluster nitrides and dinitrides are derived from threshold analysis of the energy dependence of the endothermic reactions using several different approaches. These values show only a mild dependence on cluster size over the range studied, although the Co13+–N bond energy is relatively weak. The bond energies of Con+–N for larger clusters suggest that a reasonable value for the desorption energy of atomic nitrogen from bulk phase cobalt is 6.3±0.2 eV, which is somewhat lower than the only available value in the literature, an estimate based on the enthalpy of formation of bulk cobalt nitride. The trends in the cobalt nitride thermochemistry are also compared to previously determined metal-metal bond energies, D0(Con+–Co), and to D0(Fen+–N). Implications for catalytic ammonia production using cobalt versus iron are discussed. [ABSTRACT FROM AUTHOR]

We have studied spin-dependent tunneling in La2/3Ba1/3MnO3-δ based trilayer magnetic tunnel junctions fabricated by pulsed laser deposition. In the heteroepitaxial trilayer structures, a strained SrTiO3 layer of different thickness was used as a tunneling barrier. For the junctions with a SrTiO3 barrier, the measured tunneling characteristics deviated considerably from the ideal characteristics expected for elastic tunneling through an ideal barrier. The data indicate that inelastic multistep tunneling as described by the Glazman-Matveev model is present. Our analysis indicates that the SrTiO3 barrier layer consists of two different parts: The interface region with the manganite electrodes containing a high density of structural defects, and the central barrier layer with a small density of defects. The observed temperature dependence of the junction resistance can be explained by a series connection of the resistance contributions from the interfacial and central barrier part. The magnetic field dependence of the junction resistance is found to depend strongly on the barrier thickness and can show complicated behavior due to both a complex magnetic state in the junction electrode and magnetic interactions between the ferromagnetic electrodes. A very large tunneling magnetoresistance up to ΔR/Rp≃1200% is observed that, however, depends sensitively on the magnetic history. [ABSTRACT FROM AUTHOR]

Current-induced spin-torque switching was demonstrated on sub-100 nm magnetic tunnel junction devices fabricated on 200 mm substrates utilizing 180 nm complimentary metal–oxide–semiconductor back-end-of-the-line (BEOL) technology. Low resistance-area (RA) product and high tunneling magnetoresistance (TMR) were achieved by using substrates containing a CoFeB free layer and a thin MgO barrier. To obtain the desired sub-100 nm features, photoresist trimming was applied on patterns created by a 248 nm lithography tool. Furthermore, the magnetic stack was defined using an ion beam etch that stopped on the thin MgO barrier. Field-sweep measurements on elliptical devices that are 80 nm wide and 160 nm long indicated RA∼4 Ω μm2 and TMR∼90%. Upon injecting current into the devices while applying an external offset field of 28 Oe, current-induced switching occurred from parallel (P) to antiparallel (AP) state at +1.3 mA, and from AP to P state at -1.25 mA. BEOL process integration on 200 mm substrates enabled statistical analysis of device properties, such as the observation of two breakdown mechanisms in the devices. [ABSTRACT FROM AUTHOR]

We investigated the influence of the irregular shape of air holes on the optical characteristics of channel-drop filters built in a two-dimensional photonic crystal slab. Three differently shaped structures are tested by experiments and simulations to demonstrate the shape-tuning capability of the optical devices. A four-channel filter based on this shape design is presented. The photonic crystal consists of a triangular array of air holes fabricated by focused ion beam lithographic technology on a silicon slab with thickness of 260 nm. The filter contains a heterostructure with different lattice constants of 420 and 430 nm. In each channel, the filtering functionality is guaranteed by the indirect resonant coupling between waveguide and cavity. The elliptical air holes that surround the cavity have different parameters, and this leads to a fine tuning of the cavity’s resonant frequencies. The performance of the multichannel filter is found to be very encouraging. [ABSTRACT FROM AUTHOR]

Extreme ultraviolet (EUV) discharge-based lamps for EUV lithography need to generate extremely high power in the narrow spectrum band of 13.5±0.135 nm. A simplified collisional-radiative model and radiative transfer solution for an isotropic medium were utilized to investigate the wavelength-integrated light outputs in tin (Sn) plasma. Detailed calculations using the Hebrew University-Lawrence Livermore atomic code were employed for determination of necessary atomic data of the Sn4+ to Sn13+ charge states. The result of model is compared with experimental spectra from a Sn-based discharge-produced plasma. The analysis reveals that considerably larger efficiency compared to the so-called efficiency of a black-body radiator is formed for the electron density ≃1018 cm-3. For higher electron density, the spectral efficiency of Sn plasma reduces due to the saturation of resonance transitions. [ABSTRACT FROM AUTHOR]

PbTiO3 nanorods with tetragonal phase were synthesized by hydrothermal method and heat treatment, and temperature-dependent electrical transport properties of individual PbTiO3 nanorod were investigated. The results show that the conductivities of PbTiO3 nanorods are gradually enhanced with temperature increasing from 77.4 to 295 K, and exhibit the typical nonlinear I–V characteristics. The barrier height between Au electrode and nanorod is reduced from 0.137 to 0.088 eV with increasing bias from 0.2 to 1 V. The corresponding values of thermal activation energies are 0.172 and 0.06 eV below the conduction band for 180–295 and 77.4–180 K, respectively. This semiconductor-like behavior may result from the larger number of surface defects or localized states in the amorphorized PbTiO3. [ABSTRACT FROM AUTHOR]

Presents information on a study which investigated the image blurring as a result of stochastic particle-particle interactions for projection electron- and ion-beam lithography systems. Physical basis of nearest-neighbor theory; Ways to optimize the electron-optic; Application of n-n theory to projection systems; Conclusions.

A new approach for calculating the ion dose spatial distribution of the focused ion beam is proposed. The approach is based on the analysis of the secondary electron microscopy image of the area irradiated by the focused ion beam. [ABSTRACT FROM AUTHOR]

The work presents experimental data of Ga+ focused ion beam etching of disc and ring patterns in Si3N4/GaN structure. The reasons for the difference in etching depth between the discs and the rings are described. [ABSTRACT FROM AUTHOR]

The detection of quantal exocytic events from neurons and neuroendocrine cells is a challenging task in neuroscience. One of the most promising platforms for the development of a new generation of biosensors is diamond, due to its biocompatibility, transparency and chemical inertness. Moreover, the electrical properties of diamond can be turned from a perfect insulator into a conductive material (resistivity ~mΩ·cm) by exploiting the metastable nature of this allotropic form of carbon. A 16‑channels MEA (Multi Electrode Array) suitable for cell culture growing has been fabricated by means of ion implantation. A focused 1.2 MeV He+ beam was scanned on a IIa single-crystal diamond sample (4.5 × 4.5 × 0.5 mm3) to cause highly damaged sub-superficial structures that were defined with micrometric spatial resolution. After implantation, the sample was annealed. This process provides the conversion of the sub-superficial highly damaged regions to a graphitic phase embedded in a highly insulating diamond matrix. Thanks to a three-dimensional masking technique, the endpoints of the sub-superficial channels emerge in contact with the sample surface, therefore being available as sensing electrodes. Cyclic voltammetry and amperometry measurements of solutions with increasing concentrations of adrenaline were performed to characterize the biosensor sensitivity. The reported results demonstrate that this new type of biosensor is suitable for in vitro detection of catecholamine release.

Nanodots consisting of Co/Pt multilayer have been fabricated using nanosphere lithography and ion beam etching. The nanodots retained the perpendicular anisotropy as that of the continuous films. However, the coercivity of the nanodots was greatly enhanced, more substantially for smaller nanodots. Concurrently, the remnant magnetization was reduced to 50%–80%. Magnetic force microscopy revealed that the domain pattern of nanodots at the remnant state was largely single domain but with nonperpendicular stray fields on the edges, indicating noncollinear alignment of magnetizations in those regions. [ABSTRACT FROM AUTHOR]

Large arrays of permalloy (Ni81Fe19) annular structures were fabricated using a self-aligned patterning process based on ion-beam proximity lithography (IBPL), where a broad beam of energetic He ions is shaped into billions of ion beamlet by a stencil mask to pattern electron beam sensitive resist. IBPL was used to form an array of circular openings in poly(methyl methacrylate) (PMMA) resist, followed by a tone reversal process to form circular pillars in an underlying polymethylglutarimide (PMGI) layer. The PMGI pillars were conformally coated with silicon oxide, which was followed by anisotropic reactive ion etch (RIE) to form silicon oxide rings, which were transferred into the underlying sputter deposited permalloy thin film by ion milling. This fabrication approach was used to make 6 x 6 mm2 arrays of rings on a constant pitch of 670 nm with the outer diameters varied between 350 nm and 450 nm with a fixed inner diameter of 150 nm. Three unique samples that were fabricated and characterized using a vibrating sample magnetometer. The measured M-H loops showed the switching from an onion to a vortex and back to an onion state and are in good agreement with micromagnetic simulations and previously published data. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, 3D volumetric energy deposition and local crosslinking of hydrogen silsesquioxane (HSQ) are experimentally and numerically explored in focused helium ion beam lithography (HIBL). In particular, a through‐membrane exposure method is developed to make visible and subsequently to measure the 3D interaction volume and energy deposition of helium ions in HSQ. By comparing the actual dimensions of the crosslinked HSQ structures with Monte Carlo modeling of the spatial distribution of the energy deposition, the critical energy density for crosslinking HSQ is obtained. Finally, 3D nanofabrication of complex crosslinked HSQ nanostructures such as embedded nanochannels and suspended grids is demonstrated using two different exposure configurations. The proposed method expands the 2D point spread function of HIBL into three dimensions, thus opening a new avenue for nanoscale 3D fabrication. [ABSTRACT FROM AUTHOR]

Electron Beam Lithography (EBL) at sub-10 nm resolution is mainly limited by resist contrast and proximity effects. In this work, we investigate the use of a recently developed alumina-based resist as a negative-tone resist for EBL at 100 keV and focused helium ion beam lithography (FHIBL). The resist is synthesized using a sol-gel method and turns into a near completely inorganic alumina system when exposed to the electron/ion beam. We first investigate the effect on the resist contrast curve on i) development temperature; ii) stability of the resist after exposure and before post-baking and development; and iii) aging of the resist solution. We demonstrate the patterning of isolated features as small as 6.5 nm using an EBL and 5 nm using FHIBL and a resolution down to 10 nm for FHIB exposed films. Finally, we demonstrate the pattern transfer of 10 nm lines with an aspect ratio of 10 in silicon, using an optimized reactive ion etching process. [ABSTRACT FROM AUTHOR]

High-resolution focused ion beam lithography has been used to fabricate YBa2Cu3O7-x (YBCO) wires with nanometric lateral dimensions. In the present work, we investigate Flux-flow instabilities in nanowires of different widths, showing sudden voltage switching jumps from the superconducting to the normal state. We present an extensive study on the temperature and field dependence of the switching characteristics which reveal that voltage jumps become less abrupt as the temperature increases, and disappear at the vortex-liquid state. On the contrary, the current distribution at the critical point becomes narrower at high temperatures. Sharp voltage switchings very close to the critical current density can be obtained by reducing the width of the nanowires, making them very appealing for practical applications. [ABSTRACT FROM AUTHOR]

Recently, carbon ion beam based therapies are becoming important in the medical field including dosimetric applications. The present study focuses on the synthesis, and dosimetric characteristics of CaSO 4 :Dy nanophosphors (NPs) irradiated by 200 keV C ions. This NPs was prepared by chemical co-precipitation method , irradiated at different fluences of low energy C ion and characterized for the structural, morphological and thermoluminescence (TL) properties. X-Ray Diffraction of the NPs revealed that the hkl peak intensities, as well as crystalline sizes, decreased with increasing ion fluences. Transmission Electron Microscopy results showed that the particle surface found to be damaged due to ion irradiation. From Fourier Transform Infra-Red spectra, the wave numbers ranging from 2000 cm −1 to 2450 cm −1 and 800 cm −1 to 1800 cm −1 have drastically changed in terms of intensity, the shape, and several bonds were observed to be broken and merge due to the C ion induced effects. Moreover, the surface morphology also shows systematic changes. This CaSO 4 :Dy NPs was found to be a quite sensitive to TL dosimetric properties in the fluence range of 1 × 10 13 to 5 × 10 14 ions/cm 2 . The TL properties such as glow curve, sensitivity response, fading, and trapping parameters have been calculated. The patterns that emerge suggest that different trapping mechanisms are operating as evident from their glow curve deconvolution (GCD) functions. The CaSO 4 :Dy NPs can be effectively used to detect the dose of 200 keV C ions during therapy as a medical dosimetry or vivo dosimetry. [ABSTRACT FROM AUTHOR]

Coherently embedded structures in a crystalline substrate are known as endotaxial structures. In this paper, we report on the growth of silver (Ag) endotaxial structures in silicon using the aspects of both ion implantation and irradiation. In one case, endotaxial nanostructures of Ag at the Si interface are formed with 30 keV negatively charged silver ions (Ag − ) on GeO x /SiO x /Si system. In another case, 30 keV Ag − ions are used to create defects in GeO x , SiO x and in silicon substrate. Further deposition of a thin layer of Ag on irradiated GeO x /SiO x /Si system yielded endotaxial Ag nanostructures relatively at lower temperature (700 °C) compared to the system without any irradiation effects. We also reveal that the irradiation effects with 1.8 MeV Ag + ions do not influence the early onset temperature of endotaxial nanostructure formation (unlike low energy ions). We show that it is essential to have crystalline silicon substrate to form Ag endotaxial nanostructures to grow endotaxial structures. [ABSTRACT FROM AUTHOR]

Minimal proximity effect coupled with uniform energy deposition in thin polymer layers make Proton Beam Writing (PBW) an intuitive direct-write lithographic technique. Feature sizes matching the focused beam spot size have been fabricated in photoresists down to 19 nm. Reproducible sub-10 nm beam focusing will make PBW a promising contender for sub-10 nm lithography. In this paper, we present beam size characterization by imaging a PBW resolution standard using transmitted/scattered ions and secondary electrons. Using Scanning Transmission Ion Microscopy (STIM) spectra for 1 and 2 MeV H 2 + beams, we experimentally measure the thickness of the resolution standard to be 0.9 ± 0.1 μm, applying two independent calibration methods, which match the original intended thickness during fabrication. Through bias optimization of a Micro-Channel Plate (MCP), we show a tuneable secondary electron detection per proton for imaging with a maximum of 75% e/p for a beam of 1 MeV H 2 + . Based on STIM mode beam size measurement, we discuss considerations for quadrupole system alignment in order to remove higher order translational and rotational misalignments critical to achieve sub-40 nm spot sizes. A spot size of 13 × 32 nm 2 (STIM) was achieved using a newly developed interface, capable of autofocusing ion beams and performing PBW. [ABSTRACT FROM AUTHOR]

In the present work, we report on the monolithic fabrication by means of ion beam lithography of hollow micro-channels within a diamond substrate, to be employed for microfluidic applications. The fabrication strategy takes advantage of ion beam induced damage to convert diamond into graphite, which is characterized by a higher reactivity to oxidative etching with respect to the chemically inert pristine structure. This phase transition occurs in sub-superficial layers thanks to the peculiar damage profile of MeV ions, which mostly damage the target material at their end of range. The structures were obtained by irradiating commercial CVD diamond samples with a micrometric collimated C + ion beam at three different energies (4 MeV, 3.5 MeV and 3 MeV) at a total fluence of 2 × 10 16 cm −2 . The chosen multiple-energy implantation strategy allows to obtain a thick box-like highly damaged region ranging from 1.6 μm to 2.1 μm below the sample surface. High-temperature annealing was performed to both promote the graphitization of the ion-induced amorphous layer and to recover the pristine crystalline structure in the cap layer. Finally, the graphite was removed by ozone etching, obtaining monolithic microfluidic structures. These prototypal microfluidic devices were tested injecting aqueous solutions and the evidence of the passage of fluids through the channels was confirmed by confocal fluorescent microscopy. [ABSTRACT FROM AUTHOR]

The concept of fluorescent sensing in a microchannel equipped with focusing light Fresnel lenses has been demonstrated. The concept employs a line or array of Fresnel lenses generating a line or array of focused light spots within a microfluidic channel, to increase the sensitivity of fluorescent signal detection in the system. We have presented efficient methods of master mold fabrication based on the lithography method and focused ion beam milling. The flexible microchannel was fabricated by an imprint process with new thiolene-epoxy resin with a good ability to replicate even submicron-size features. For final imprinted lenses, the measured background to peak signal level shows more than nine times the increase in brightness at the center of the focal spot for the green part of the spectrum (532 nm). The effectiveness of the microlenses in fluorescent-marked Escherichia coli bacteria was confirmed in a basic fluoroscope experiment, showing the increase of the sensitivity of the detection by the order of magnitude. [ABSTRACT FROM AUTHOR]

Focused ion beam nanoscale synthesis has emerged as a critical tool for selected area nanofabrication. Helium and neon ion beams from the gas field ion source have recently demonstrated unparalleled resolution among other scanning ion beams. In this review, the authors focus on the nanoscale synthesis applications for these ion species which have been demonstrated to date. The applications and recent work can broadly be grouped into the following categories: (1) Monte Carlo simulations, (2) direct-write milling or sputtering, (3) ion beam lithography, (4) selective ion implantation or defect introduction and (5) gas-assisted processing. A special emphasis is given toward using He+ and Ne+ for the processing of two dimensional materials, as several groups have demonstrated promising results. Finally, the authors will discuss the future outlook of He+ and Ne+ nanoprocessing techniques and applications. [ABSTRACT FROM AUTHOR]