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In the present article, ion-beam lithography in ion-exchanged glasses is used as a method for the fabrication of miniaturized phase optical diffractive elements. It is established that, as a result of the interaction of a low-energy (∼ 40 keV) He+ ion beam with silver-ion-exchanged glasses, the index of refraction of interacted area increases. In the interacted areas of the samples, the formation of neutral silver nanoparticles leads to an increase in the index of refraction. This paves the way to employ such material to produce optical phase diffractive elements such as slits, gratings, or Fresnel’s zone plates. It is found that a remarkable dispersion for the index of refraction (n = n(λ)) gives rise to the dependence of diffraction efficiency of produced elements to the wavelength of the probe beams. The produced elements are of good quality, optically effective, chemically stable, waterproof, and scratch resistant.

Focused ion beam sources have recently been commercialized and are increasingly utilized for applications in nanotechnology. There is a desire to pattern large designs, millimeter in scale, while still achieving sub-nanometer resolution in the smallest features. However, focused helium ion beams are restricted to fields of view of roughly 100 micrometers. Recently, we have developed an automated process for layout designs with feature sizes from sub-nanometer to millimeter scales, using Raith lithography software in a Zeiss Orion Plus helium ion microscope. The technique relies on stitching writefields together and incorporating automated focusing algorithms in the Raith software. This procedure was demonstrated by scaling and automating the process of producing ion-damaged Josephson junctions in arrays in the high-temperature superconducting material YB $_2$ C $_3$ O $_{7-\delta }$ . We demonstrate that the automated process reduces operator input while maintaining consistency at the smallest resolutions.

The investigation of secondary effects induced by ionizing radiation represents a new and ever-growing research field in radiobiology. This new paradigm cannot be investigated only using standard instrumentation and methodologies, but rather requires novel technologies to achieve significant progress. In this framework, we developed diamond-based sensors that allow simultaneous real-time measurements with a high spatial resolution of the secretory activity of a network of cells cultured on the device, as well as of the dose at which they are exposed during irradiation experiments. The devices were functionally characterized by testing both the above-mentioned detection schemes, namely: amperometric measurements of neurotransmitter release from excitable cells (such as dopamine or adrenaline) and dosimetric evaluation using different ionizing particles (alpha particle and X-ray photons). Finally, the sensors were employed to investigate the effects induced by X-rays on the exocytotic activity of PC12 neuroendocrine cells by monitoring the modulation of the dopamine release in real-time.

Given the current need for resist materials for patterning transistors with ultralow nodes, there has been a quest for developing resists with improved performance for nanoscale patterning with goo...

The performance enhancements of Si junctionless transistors (JLTs) with a short gate length (LG) below 10 nm by a pronounced ferroelectric (FE) gate dielectric were demonstrated for the first time. A TiN gate with LG = ∼8 nm was defined by helium ion beam lithography (HIBL) using hydrogen silsesquioxane as a resist. As compared with the paraelectric HfO2 gate oxide, the FE Hf0.5Zr0.5O2 gate dielectric leads to a suppression of the off-state current (IOFF) by ∼2 orders of magnitude and a reduction of the minimum subthreshold swing (SS) to ∼33 mV dec−1, along with an enhancement of the on/off ratio in the reverse-sweep direction in JLTs with LG = ∼8 nm. JLTs with a long LG = 5 μm were also investigated for comparison, revealing a decrease of IOFF by ∼25× and the sub-60 mV dec−1 SS across ∼3 orders of drain current (ID) under a large drain voltage (VD = 0.5 V) operation during the reverse sweep in FE JLTs. A time domain analysis indicated that the transient negative capacitance (TNC) effect takes place in the FE gate dielectric. A physical model was proposed to account for the TNC effect and the sub-60 mV dec−1 SS based on the capacitance increase during the FE polarization switching. This study also demonstrates for the first time the fabrication of nanoelectronic devices with a sub-10 nm critical dimension by using the HIBL technique with a damage-free dose.

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.

We discuss physical processes underlying the generation of ion beams with high emission current density in electrohydrodynamic (EHD) emitters based on liquid metals and alloys and with room temperature ionic liquids. We consider EHD effects that influence the emission of ions (ion production mechanisms) and the kinetics of ion interactions in high-density beams. We analyze the factors determining the emission zone size, sustainability of emission at high and low currents, generation of clusters, increase in energy spread, decrease in brightness, and other features of ion beams. We consider the specific design features of EHD emitters and the problems of practically ensuring their stable operation. Discussed in detail are modern application areas for ion sources with EHD emitters, including technological installations for ion beam lithography, micro- and nanopatterning, ion microscopes and tools for local mass spectrometry of secondary ions, and systems to control and neutralize the potential of spacecraft as well as electrostatic rocket engines (microthrusters). We analyze prospects for further development of EHD emitters themselves and instruments based on them.

Since the fabrication of micro-/nanoelectronic devices are marching toward ultralow node technology with dense patterns to meet the current industry demands, continuous advancement is needed in ter...

Hybrid metal-organic cluster resist materials, also termed as organo-inorganics, demonstrate their potential for use in next-generation lithography owing to their ability for patterning down to ∼10 nm or below. High-resolution resist patterning is integrally associated with the compatibility of the resist and irradiation of the exposure source. Helium ion beam lithography (HIBL) is an emerging approach for the realization of sub-10 nm patterns at considerably lower line edge/width roughness (LER/LWR) and higher sensitivity as compared to electron beam lithography (EBL). Here, for the first time, a negative tone resist incorporating nickel (Ni)-based metal-organic clusters (Ni-MOCs) was synthesized and patterned using HIBL and EBL at 30 keV. This resist comprises a nickel-based metal building unit covalently linked with the organic ligand: m-toluic acid (C

Our research is devoted to the shrinkage and swelling of PMMA film after micro-structuring with ion beam lithography. 10 MeV O4+ ions were used in the experiment. Parallel lines of 1 mm in length and 10 μm in thickness were created. The number of scan cycles and ion fluence were varied. The influence of the irradiation regime on PMMA elemental composition in micro-structured parts and microstructure morphology were studied. It was shown that microstructures created in PMMA film undergo both shrinkage and swelling processes depending on both the scan speed and the fluence. For the same fluence, shrinkage appears at fast scan speeds and swelling at slow ones. The same phenomenon was found in relation to the fluence for the same scan speed. It was observed that PMMA film rupture caused by irradiation occurred prior to the start of the carbonization of the irradiated area.

In neuroscience, a deep understanding of communication mechanisms at the cellular level is of paramount importance, since their dysfunction determines the onset of several diseases. The development of innovative sensors devoted to the investigation of both chemical and electrical signals it is therefore essential to improve the outcome of standard trials and to define novel methodologies. Here we report on the fabrication and the characterization of multi-functional micrographite patterned diamond multi-electrode arrays. These sensors are obtained by means of a three-dimensional patterning process of single-crystal diamond substrates by means of MeV ion-beam-based lithography, which allows the direct fabrication of graphitic micro-channels embedded within the bulk of the electrically insulating diamond matrix. Proof-of-concept in vitro experiments on cultured neurons and cardiac tissue were performed, in which quantal secretory events were amperometrically recorded from dopaminergic neurons, while potentiometric measurements of action potential generation were collected from both hippocampal neuronal networks and intact sinoatrial nodes. These achievements represent the demonstration of the applicability of an all-carbon hybrid graphite/diamond device for the multi parametric detection of chemical and electrical signals, thus representing a fundamental step for the simultaneous in vitro measurement of the two types of signals from the same biological sample.

Our work presents and investigates the effectiveness of a model-based proximity effect correction method for helium ion beam lithography (HIBL). This method iteratively modulates the shape of a pattern by a feedback compensation mechanism until the simulated patterning fidelity satisfies specific constraints. A point spread function (PSF) is utilized to account for all phenomena involved during the scattering events of incident ion beam particles in the resist. Patterning prediction for subsequent correction process is derived from the energy intensity distribution due to convolution between the PSF and the pattern, with an adequate cut-off threshold. The performance of this method for HIBL is examined through several designed layouts from 15- to 5-nm in half pitches, under specific process parameters, including acceleration voltage, resist thickness, and resist sensitivity. Preliminary results show its effectiveness in improving the patterning fidelity of HIBL.

Focusing on the potential applications of tailored graphene nanoribbons (t-GNRs), in this work, we systematically study size effects on the electronic transport in t-GNR-based molecular junctions. As a result of the manufacturing error generated during the processing or synthesis of t-GNRs using techniques such as ion beam lithography, the final dimensions of the as-fabricated devices often deviate from the design values, giving rise to a size distribution around the mean value which could considerably affect the device performance. To simulate the effects of the manufacturing error, a series of t-GNR-based junctions with various dimensions have been modelled and systematically investigated using density functional theory (DFT) coupled with the non-equilibrium Green's function (NEGF). For junctions that consist of an acene chain connected with two graphene nanosheets, it is found that the chain length has little influence on the electronic transport and that, on the other hand, the junction conductivity is significantly altered by its width due to the different number and nature of the electron transfer pathways. Furthermore, increasing the width of the junction leads to a clear odd-even variation of decreasing amplitude in its transport behavior. These findings underpin further fundamental and device-based studies of t-GNRs.

We demonstrate the capabilities of ion-beam lithography (IBL) for the manufacturing of the X-ray refractive micro-optics. For the first time with the help of IBL, the hardest of current materials – diamond – was milled, and microscale diamond half-lenses were produced. Lenses have a rotationally parabolic profile with radii of parabola apexes in the range from 3 to 10 μm. As has been confirmed with SEM, the surface of produced lenses was free of low- and high-frequency modulations: figure errors of fabricated lenses were < 200 nm, while the surface roughness was estimated to be 30 nm. The optical performance of the lens was successfully tested at a third-generation synchrotron, where the lenses provided diffraction-limited focusing of X-ray radiation and demonstrated intensity profiles with Gaussian distributions at every measured longitudinal position (along the optical axis) downstream of the optics.

Optics express 28(4), 4773 - 4785 (2020). doi:10.1364/OE.384647, We demonstrate that ion-beam lithography can be applied to the fabrication of rotationally parabolic refractive diamond X-ray micro-lenses that are of interest to the field of high-resolution X-ray focusing and microscopy. Three single half-lenses with curvature radii of 4.8 µm were produced and stacked to form a compound refractive lens, which provided diffraction-limited focusing of X-ray radiation at the P14 beamline of PETRA-III (DESY). As shown with SEM, the lenses are free of expressed low- and high-frequency shape modulations with a figure error of < 200 nm and surface roughness of 30 nm. Precise micro-manipulation and stacking of individual lenses are demonstrated, which opens up new opportunities for compact X-ray microscopy with nanometer resolution., Published by Soc., Washington, DC

Controlling the propagations of surface plasmon polaritons (SPPs) is important for many applications. Now, mainly structures for controlling SPPs are etched directly in the metal surface through experimental methods, such as focus ion beam lithography (FIB). In view of mature technology in processing dielectric products, we propose the metal-dielectric composite holography (MDCH) method to design dielectric structures for controlling the propagation of SPPs. The holographic groove structures are designed in dielectric film to control SPP propagation through the surface electromagnetic wave holography (SWH) method. The mutual coherence theory is applied to analyze the influence of the grooves in dielectric film on the phase of propagating SPPs, and the reconstruction condition is obtained. Based on the analysis results, two schemes are proposed to make MDCH structures satisfy the condition: reducing the width of the grooves or filling the grooves with another dielectric. The finite difference time domain (FDTD) method is applied to test the two schemes. Simulation results prove that two schemes are feasible when the width of the groove is smaller than 40 nm or the refractive index of the filling dielectric is limited to a certain range. The investigation verifies that the MDCH method is feasible and the SPP waves can be controlled with high efficiency. Based on the investigation, the mature hologram-fabricated methods and dielectric-processing methods may be used to fabricate structures for controlling SPP waves. The MDCH method may open up the possibility for mass production of plasmonic devices, avoiding the FIB experimental method.

Interaction volume of beam-resist is a basis unit of beam-lithography, directly determines the critical parameters of beam-lithography. We have visualized the interaction volume at the state-of-the-art sub-10 nm scale by a spot irradiation of sub-nanometer helium ion beam into an approximately free-standing resist. The visualized interaction volume suggests helium ion beam has an excellent capability in nanofabrication. Specifically, helium ion beam-lithography is 1000 times more efficient than electron beam-lithography (EBL), owns a sub-4 nm resolution, can achieve a large pattern aspect ratio (greater than 8), and does not suffer from backscattering effect at a normal exposure dose. Furthermore, the interaction volume has been theoretically studied by considering the spatial distribution of energy deposited in the resist, and eventually lead to a model for pattern prediction and proximity effect corrections. We expect that, our approach to visualize the interaction volume may be applied to study other high resolution lithographic techniques such as x-ray lithography and EBL, and it may open new possibilities in other applications, like beam-imaging, beam-milling, and beam-modification.

We introduce a helium ion beam lithography and liftoff process to fabricate arbitrary nanostructures. Exploiting existing high-resolution positive tone resists such as poly (methyl methacrylate) (PMMA), the process offers three significant advantages over electron beam lithography: (a) the exposing helium ion beam produces a high secondary electron yield leading to fast patterning, (b) proximity effects are negligible due to the low count of backscattered helium ions from the substrate, and (c) the process is transferrable with minimal alteration among different types of substrates (e.g. silicon, fused silica). The process can be used to pattern any material compatible with liftoff such as evaporated metals or dielectrics, and allows overlay of nanostructures precision-aligned to microstructures realised beforehand on the same substrate. The process is demonstrated for several PMMA thicknesses to liftoff different thicknesses of deposited material. Resolution trials are conducted to determine the limits of the process for each PMMA thickness. Isolated lines as narrow as 14 nm, and line-space gratings of 40 nm pitch (50% duty cycle), are produced as resolution tests by lifting off a 20 nm thick Au film. Nanostructures of aspect ratio up to ∼3:1 have been realised. Plasmonic nanoantenna arrays overlaid to microscale contacts are produced as device demonstrators, for which optical measurements are in excellent agreement with theory.

Microscopes and various forms of interferometers have been used for decades in optical metrology of objects that are typically larger than the wavelength of light λ. Metrology of sub-wavelength objects, however, was deemed impossible due to the diffraction limit. We report the measurement of the physical size of sub-wavelength objects with deeply sub-wavelength accuracy by analyzing the diffraction pattern of coherent light scattered by the objects with deep learning enabled analysis. With a 633 nm laser, we show that the width of sub-wavelength slits in an opaque screen can be measured with an accuracy of ∼λ/130 for a single-shot measurement or ∼λ/260 (i.e., 2.4 nm) when combining measurements of diffraction patterns at different distances from the object, thus challenging the accuracy of scanning electron microscopy and ion beam lithography. In numerical experiments, we show that the technique could reach an accuracy beyond λ/1000. It is suitable for high-rate non-contact measurements of nanometric sizes of randomly positioned objects in smart manufacturing applications with integrated metrology and processing tools. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) Published version The authors acknowledge the Singapore Ministry of Education (Grant No. MOE2016-T3-1-006); the Agency for Science, Technology and Research (A∗ STAR), Singapore (Grant No. SERC A1685b0005); and the Engineering and Physical Sciences Research Council UK (Grants No. EP/N00762X/1 and No. EP/M0091221), and the European Research Council (Advanced grant FLEET786851). T.P. acknowledges support from the China Scholarship Council (CSC No. 201804910540).

Co/Pt multilayer dots arrays with 580-nm periodicity were fabricated using Laser interference lithography (LIL) and an ion-beam milling technique. We obtained uniform dots arrays with a large area by optimizing the exposure parameters and improving exposure conditions. We obtained their shapes and magnetic domain structures and investigated using an Atomic force microscope (AFM) and Magnetic force microscope (MFM). The AFM and MFM images show: 1) when their size is smaller than 400nm, the dots are in single-domain state and their shape tends to be circular; and 2) when their size is greater than 400nm, the dots are in multi-domain state and they tend to form squares. The dots arrays possibly can be used in nano-scale magnetic storage.

Developing high technologies but in economic manners is necessary and also feasible for developing countries. At Chiang Mai University, Thailand, we have developed MeV-ion microbeam technology based on a 1.7-MV Tandetron tandem accelerator with our limited resources in a cost-effective manner. Instead of using expensive and technically complex electrostatic or magnetic quadrupole focusing lens systems, we have developed cheap MeV-ion microbeams using programmed L-shaped blade aperture and capillary techniques for MeV ion beam lithography or writing and mapping. The programmed L-shaped blade micro-aperture system consists of a pair of L-shaped movable aperture pieces which are controlled by computer to cut off the ion beam for controlling the beam size down to the micrometer order. The capillary technique utilizes our home-fabricated tapered glass capillaries to realize microbeams. Either system can be installed inside the endstation of the MeV ion beam line of the accelerator. Both systems have been applied to MeV-ion beam lithography or writing of micro-patterns for microfluidics applications to fabricate lab-on-chip devices. The capillary technique is being developed for MeV-ion beam mapping of biological samples. The paper reports details of the techniques and introduces some applications.

A technique for forming a nanosized gate of a high-power microwave transistor is proposed. The optimal exposure parameters of 950-PMMA-A2 and ELP-20 resists are established. The technological route of ion beam lithography with the use of multilayer resists is investigated. A technique for fabricating a continuous mesh of earthed alignment marks formed on the ion-sensitive resist to visualize the alignment marks on a dielectric substrate by ion microscopy is developed.

The availability of metrology solutions, one of the critical factors to drive leading-edge semiconductor devices and processes, can be confronted with difficulties in the advanced nodes. For developing new metrology solutions, highquality test structures fabricated at specific sizes are needed. Electron-beam direct-write lithography has been utilized to manufacture such samples. However, it can encounter significant-resolution difficulties and require complicated process optimization in sub-10-nm nodes. This study investigates the feasibility and patterning control of metrology test structure fabrication by helium-ion-beam direct-write lithography (HIBDWL). Features down to IRDS 1.5-nm node are resolvable without needing any resolution enhancement technique from the lithography simulation. Further, patterns beyond 1.5-nm node can be achievable with the help of proximity effect correction technique. Preliminary results of simulation demonstrate that HIBDWL can be a promising alternative for fabricating programmed defects (PDs) and test structure to develop advanced metrology solutions in sub-7-nm nodes.

In the present work, we report on the fabrication of a diamond-based device targeted to the detection of quantal neurotransmitter release. We have developed Multi-electrode Arrays with 16 independent graphitic channels fabricated by means of Deep Ion Beam Lithography (DIBL). These devices are capable of detecting the in vitro exocytotic event from neurosecretory cells, while overcoming several critical limitations of standard amperometric techniques.

Field-emission devices are promising candidates to replace silicon fin field-effect transistors as next-generation nanoelectronic components. For these devices to be adopted, nanoscale field emitters with nanoscale gaps between them need to be fabricated, requiring the transfer of, for example, sub-10 nm patterns with a sub-20 nm pitch to substrates like silicon and tungsten. New resist materials must therefore be developed that exhibit the properties of sub-10 nm resolution and high dry etch resistance. A negative tone, metal–organic resist is presented here. It can be patterned to produce sub-10 nm features when exposed to helium ion beam lithography at line doses on the order of tens of picocoulombs per centimeter. The resist was used to create 5 nm wide, continuous, discrete lines spaced on a 16 nm pitch in silicon and 6 nm wide lines on an 18 nm pitch in tungsten, with line edge roughness of 3 nm. After the lithographic exposure, the resist demonstrates high resistance to silicon and tungsten dry etch conditions (SF_6 and C_4F_8 plasma), allowing the pattern to be transferred to the underlying substrates. The resist’s etch selectivity for silicon and tungsten was measured to be 6.2:1 and 5.6:1, respectively; this allowed 3 to 4 nm thick resist films to yield structures that were 21 and 19 nm tall, respectively, while both maintained a sub-10 nm width on a sub-20 nm pitch.

Resist-based ion beam lithography has been studied by exposing different species of ions (He+, Si++, Ga+ and Au++) on 700 and 2000 Å thick poly(methyl methacrylate) (or PMMA) films supported on Si substrates. By comparing the resist sensitivities to different ions and the cross-sectional shapes of the developed features with the simulation outputs from the TRIM (TRansport of Ions in Matter) software, long-chain scissoring in PMMA can be largely attributed to ion-initiated electron cascades (as evaluated by ion energy loss to the electrons) and recoil atom cascades (as evaluated by vacancy distribution in TRIM). The ion-initiated electron cascades contribute more to the resist sensitivity for the lighter ions, while the recoil atom cascades are more important for the heavier ions. A proportional relation between the resist sensitivity and the product of the ion energy loss to electrons and vacancy number is obtained semi-empirically for heavy ions. The He+ ion is the only ion species that can travel through and therefore expose the entire 2000-Å thick PMMA resist film, while the heaviest ion, Au++, provides the highest resist sensitivity. The effective energy and momentum impartment to the resist by the ion, as revealed by recoil atom cascades and vacancy formation, is important to significantly expanding the material types suitable for ion beam lithography.

A (Lu,Y)2SiO5:Ce (LYSO) crystal, as a heavy inorganic scintillator, is currently in high demand for various applications in the fields of particle detection. However, its high refractive index (n = 1.83) gives restriction on the measurements of rare events or weak particle flow, where high energy resolution is urgently required for detectors based on the crystal. Utilizing the electron beam lithography technique and the ion beam lithography method, we have successfully prepared a 2.0 × 2.0 mm2 large area two-dimensional photonic crystal (PhC) structure on the LYSO crystal surface. Compared with the plain reference sample, the optical measurements show a 53% enhancement of light extraction for the LYSO nanostructured surface, and the resulted improvement of energy resolution (full width at half maximum) is measured to be 43.8% by gaussian fittings to the energy spectra excited by the 241Am α source. With the advantage of high-resolution patterning, high thermal stability, and firm stickiness on the substrate, the present prescription of the PhC fabrication is still favorable for some special fields (e.g., homeland security and space exploration) though the writing process is extremely time consuming and expensive to use.

In atom beam lithography, a beam of kilo-electron-volt helium atoms illuminates a stencil mask and transmitted beamlets transfer the mask pattern to resist on a substrate. It shares the advantages of masked ion beam lithography but is immune to charging artifacts that limit resolution and pattern fidelity. This paper describes a high-brightness source of energetic He atoms, where He+ ions are extracted from a multicusp ion source, focused by two-stage accelerating optics, and neutralized by charge-transfer scattering in a differentially pumped, He-filled cell. Since scattering angles are extremely small, the straight line trajectories of scattered atoms are essentially tangent to the (possibly curved) trajectories of the parent ions. Space-charge repulsion prevents the ion beam crossing over; instead, it converges to a waist of minimum cross section before diverging further downstream. Atom trajectories produced by a cell placed in the region of intense space charge near the waist are strongly affected by the curvature of ion trajectories within the cell. The flaring of the ion beam due to space charge can be used to increase the width of the atom beam, although to the detriment of resolution. In this paper, the authors study a configuration where the cell is placed in the converging ion beam as far as practicable from the ion-beam waist. The atom beam then converges to a crossover, which becomes the virtual source seen by the mask. The source diameter and angular flux density initially increase with increasing cell pressure but saturate at higher pressures; the respective saturation values at 50 keV are 125 μm (2σ) and 8.7 × 1017 particles/s sr. Under these conditions, the beam diameter is ∼2.5 cm, 7 m from the source. A practical system for subnanometer printing is discussed with 0.2 nm (2σ) penumbral blur and 1.25 × 1013 particles/s cm2 flux density over a 1 cm circular field.In atom beam lithography, a beam of kilo-electron-volt helium atoms illuminates a stencil mask and transmitted beamlets transfer the mask pattern to resist on a substrate. It shares the advantages of masked ion beam lithography but is immune to charging artifacts that limit resolution and pattern fidelity. This paper describes a high-brightness source of energetic He atoms, where He+ ions are extracted from a multicusp ion source, focused by two-stage accelerating optics, and neutralized by charge-transfer scattering in a differentially pumped, He-filled cell. Since scattering angles are extremely small, the straight line trajectories of scattered atoms are essentially tangent to the (possibly curved) trajectories of the parent ions. Space-charge repulsion prevents the ion beam crossing over; instead, it converges to a waist of minimum cross section before diverging further downstream. Atom trajectories produced by a cell placed in the region of intense space charge near the waist are strongly affected by...

Following a brief historical summary of the way in which electron beam lithography developed out of the scanning electron microscope,three state-of-the-art charged-particle beam nanopatterning technologies are considered. All three have been the subject of arecently completed European Union Project entitled “Single Nanometre Manufacturing: Beyond CMOS”. Scanning helium ionbeam lithography has the advantages of virtually zero proximity effect, nanoscale patterning capability and high sensitivity in combinationwith a novel fullerene resist based on the sub-nanometre C60 molecule. The shot noise-limited minimum linewidthachieved to date is 6 nm. The second technology, focused electron induced processing (FEBIP), uses a nozzle-dispensed precursorgas either to etch or to deposit patterns on the nanometre scale without the need for resist. The process has potential for highthroughput enhancement using multiple electron beams and a system employing up to 196 beams is under development based on acommercial SEM platform. Among its potential applications is the manufacture of templates for nanoimprint lithography, NIL. Thisis also a target application for the third and final charged particle technology, viz. field emission electron scanning probe lithography,FE-eSPL. This has been developed out of scanning tunneling microscopy using lower-energy electrons (tens of electronvoltsrather than the tens of kiloelectronvolts of the other techniques). It has the considerable advantage of being employed without theneed for a vacuum system, in ambient air and is capable of sub-10 nm patterning using either developable resists or a self-developingmode applicable for many polymeric resists, which is preferred. Like FEBIP it is potentially capable of massive parallelizationfor applications requiring high throughput.

Helium ion beam lithography (HIL) is an emerging nanofabrication technique. It benefits from a reduced interaction volume compared to that of an electron beam of similar energy, and hence reduced long-range scattering (proximity effect), higher resist sensitivity and potentially higher resolution. Furthermore, the small angular spread of the helium ion beam gives rise to a large depth of field. This should enable patterning on tilted and curved surfaces without the need of any additional adjustments, such as laser-auto focus. So far, most work on HIL has been focused on exploiting the reduced proximity effect to reach single-digit nanometer resolution, and has thus been concentrated on single-pixel exposures over small areas. Here we explore two new areas of application. Firstly, we investigate the proximity effect in large-area exposures and demonstrate HIL's capabilities in fabricating precise high-density gratings on large planar surfaces (100 μm × 100 μm, with pitch down to 35 nm) using an area dose for exposure. Secondly, we exploit the large depth of field by making the first HIL patterns on tilted surfaces (sample stage tilted 45°). We demonstrate a depth of field greater than 100 μm for a resolution of about 20 nm.

This work presents a model-based proximity effect correction method and investigates its potential for helium ion beam lithography (HIBL). This method iteratively modulates the shape of pattern by a feedback compensation mechanism until the simulated patterning fidelity satisfied specific constraints. A point spread function is utilized to account for all phenomena involved during the scattering events of incident ion beam particle in the resist. Patterning prediction for subsequent correction process is derived from the energy intensity distribution, as a result of convolution between the point spread function and the pattern, with an adequate threshold. The performance of this method for HIBL is examined through several designed patterns from 15- to 5-nm HP under certain process parameters, including acceleration voltage, resist thickness and sensitivity. Preliminary results show its effectiveness on improving the patterning fidelity of HIBL.

Transparent conductive films of metal grating have been prepared by ion beam lithography method. The surface appearance and thickness of films were measured by atomic force microscope (AFM). Metal grating thickness uniformity has been improved to 2.34% when the flap was used to correction. Visible and near-infrared transparent have been measured by Lambda 900 spectrophotometer.

Fresnel zone plates (FZP) are diffractive photonic devices used for high-resolution imaging and lithography at short wavelengths. Their fabrication requires nano-machining capabilities with exceptional precision and strict tolerances such as those enabled by modern lithography methods. In particular, ion beam lithography (IBL) is a noteworthy method thanks to its robust direct writing/milling capability. IBL allows for rapid prototyping of high-resolution FZPs that can be used for high-resolution imaging at soft X-ray energies. Here, we discuss improvements in the process enabling us to write zones down to 15 nm in width, achieving an effective outermost zone width of 30 nm. With a 35% reduction in process time and an increase in resolution by 26% compared to our previous results, we were able to resolve 21 nm features of a test sample using the FZP. The new process conditions are then applied for fabrication of large arrays of high-resolution zone plates. Results show that relatively large areas can be decorated with nanostructured devices via IBL by using multipurpose SEM/FIB instruments with potential applications in FEL focusing, extreme UV and soft X-ray lithography and as wavefront sensing devices for beam diagnostics.

We report precise nanostructuring on genetically engineered spider silk using ion beam lithography (IBL) and electron beam lithography (EBL) to create well-defined 2D bionanopatterns and further assemble 3D bionanoarchitectures, named “Protein LEGO”, with shapes and functions on demand, serving as functional biointerfaces for structure enhanced fluorescence and guided cell seeding as proof-of-concepts. The control over the sequence and molecular weights of recombinant spider silk proteins via genetic engineering offers ease of functionalization and unprecedented lithographic resolutions and sharpness compared to natural proteins. This approach provides a facile method for patterning biomolecules within nanoscopic protein structures that could serve as the building blocks for functional nanocomponents and nanodevices.

Selective deoxygenation of graphene oxide has been conducted with regard with the design and fabrication of graphene based devices. The ion beam lithography is considered to be a powerful method for patterning onto graphene oxide foil. A helium beam has been used for both direct patterning onto graphene oxide foil and simultaneous online characterisation of its structural and compositional changes. Scanning electron microscopy, energy dispersive spectroscopy and Rutherford backscattering spectrometry analyses have been accurately employed to reveal and monitor the deoxygenation of the graphene oxide foil demonstrating the reliability of the direct patterning using the ion beam lithography technique.

International audience; 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 electron 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.

Here we demonstrate photonic integrated devices based on bioinspired peptide materials exhibiting wide optical transparency, nonlinear and electro-optical properties, and fabricated them by combining bottom-up controlled deposition of peptide large planar wafers and top-down focus ion beam lithography.

A kinoform lens is a highly efficient photonic device capable of focusing a wide range of electromagnetic radiation. Unfortunately, its realization without the need of any approximation remained elusive for a very long time. A direct, simple and precise fabrication method was still missing. Here, an efficient preparation scheme is presented for the first time. Two kinoform lenses made out of polycrystalline gold and nano-crystalline PdSi, are successfully fabricated, thoroughly characterized and tested for their ultimate focusing performances at soft X-ray energies. The fabrication is made possible by means of gray-scale direct-write ion beam lithography. A first ever 2D imaging is carried out via scanning transmission X-ray microscopy achieving resolutions down to 60 nm. The diffraction efficiency is measured to be 77% to 89% of the theoretical value and is only limited by the strong absorption at the soft X-ray energy range. The impact of materials selection on the final quality of the lens is emphasized. The overall results enable the production of almost perfect kinoform profiles with high precision. This opens unprecedented perspectives for the focusing of soft and hard X-rays at very high efficiencies and paves the way toward new applications in a wider energy range.

Bio-nanophotonics is a wide field in which advanced optical materials, biomedicine, fundamental optics, and nanotechnology are combined and result in the development of biomedical optical chips. Silk fibers or synthetic bioabsorbable polymers are the main light-guiding components. In this work, an advanced concept of integrated bio-optics is proposed, which is based on bioinspired peptide optical materials exhibiting wide optical transparency, nonlinear and electrooptical properties, and effective passive and active waveguiding. Developed new technology combining bottom-up controlled deposition of peptide planar wafers of a large area and top-down focus ion beam lithography provides direct fabrication of peptide optical integrated circuits. Finding a deep modification of peptide optical properties by reconformation of biological secondary structure from native phase to β-sheet architecture is followed by the appearance of visible fluorescence and unexpected transition from a native passive optical waveguiding to an active one. Original biocompatibility, switchable regimes of waveguiding, and multifunctional nonlinear optical properties make these new peptide planar optical materials attractive for application in emerging technology of lab-on-biochips, combining biomedical photonic and electronic circuits toward medical diagnosis, light-activated therapy, and health monitoring.

An emerging lithographic technique offers a promising alternative to electron beam lithography for fabricating new semiconductor devices with both traditional and non-traditional resists.

Fabrication processes that microelectronic developed for Integrated circuit (IC) technologies for decades, do not meet the new emerging structuration’s requirements, in particular non-IC related technologies one, such as MEMS/NEMS, Micro-Fluidics, photovoltaics, lenses. Actually complex 3D structuration requires complex lithography patterning approaches such as gray-scale electron beam lithography, laser ablation, focused ion beam lithography, two photon polymerization. It is now challenging to find cheaper and easiest technique to achieve 3D structures. In this work, we propose a straightforward process to realize 3D structuration, intended for silicon based materials (Si, SiN, SiOCH). This structuration technique is based on nano-imprint lithography (NIL), ion implantation and selective wet etching. In a first step a pattern is performed by lithography on a substrate, then ion implantation is realized through a resist mask in order to create localized modifications in the material, thus the pattern is transferred into the subjacent layer. Finally, after the resist stripping, a selective wet etching is carried out to remove selectively the modified material regarding the non-modified one. In this paper, we will first present results achieved with simple 2D line array pattern processed either on Silicon or SiOCH samples. This step have been carried out to demonstrate the feasibility of this new structuration process. SEM pictures reveals that “infinite” selectivity between the implanted areas versus the non-implanted one could be achieved. We will show that a key combination between the type of implanted ion species and wet etching chemistries is required to obtain such results. The mechanisms understanding involved during both implantation and wet etching processes will also be presented through fine characterizations with Photoluminescence, Raman and Secondary Ion Mass Spectrometry (SIMS) for silicon samples, and ellipso-porosimetry and Fourier Transform InfraRed spectroscopy (FTIR) for SiOCH samples. Finally the benefit of this new patterning approach will be presented on 3D patterns structures.

A comparison of the performance of high resolution lithographic tools is presented here. We use extreme ultraviolet interference lithography, electron beam lithography, and He ion beam lithography tools on two different resists that are processed under the same conditions. The dose-to-clear and the lithographic contrast are determined experimentally and are used to compare the relative efficiency of each tool. The results are compared to previous studies and interpreted in the light of each tool-specific secondary electron yield. In addition, the patterning performance is studied by exposing dense line/spaces patterns and the relation between critical dimension and exposure dose is discussed. Finally, the Lumped Parameter Model is employed in order to quantitatively estimate the critical dimension of line/spaces, using each tool specific aerial image. Our implementation is then validated by fitting the model to the experimental data from interference lithography exposures, and extracting the resist contrast., EIPBN 2016 Conference

The control of the charge state of nitrogen-vacancy (NV) centers in diamond is of primary importance for the stabilization of their quantum-optical properties, in applications ranging from quantum sensing to quantum computing. To this purpose, in this work current-injecting micro-electrodes were fabricated in bulk diamond for NV charge state control. Buried (i.e. 3 {\mu}m in depth) graphitic micro-electrodes with spacing of 9 {\mu}m were created in single-crystal diamond substrates by means of a 6 MeV C scanning micro-beam. The high breakdown field of diamond was exploited to electrically control the variation in the relative population of the negative (NV-) and neutral (NV0) charge states of sub-superficial NV centers located in the inter- electrode gap regions, without incurring into current discharges. Photoluminescence spectra acquired from the biased electrodes exhibited an electrically induced increase up to 40% in the NV- population at the expense of the NV0 charge state. The variation in the relative charge state populations showed a linear dependence from the injected current at applied biases smaller than 250 V, and was interpreted as the result of electron trapping at NV sites, consistently with the Space Charge Limited Current interpretation of the abrupt current increase observed at 300 V bias voltage. In correspondence of such trap-filling-induced transition to a high-current regime, a strong electroluminescent emission from the NV0 centers was observed. In the high-current-injection regime, a decrease in the NV- population was observed, in contrast with the results obtained at lower bias voltages. These results disclose new possibilities in the electrical control of the charge state of NV centers located in the diamond bulk, which are characterized by longer spin coherence times., Comment: 28 pages, 8 figures