Symposium Organizers
Alex Belianinov, Oak Ridge National Laboratory
Frances Allen, University of California, Berkeley
Shinichi Ogawa, National Institute of Advanced Industrial Science and Technology
Tom Wirtz, Luxembourg Institute of Science and Technology (LIST)
Symposium Support
Raith America, Inc.
ZEISS Microscopy
TC03.01: Gas Field Source Ion Microscopy
Session Chairs
Frances Allen
Alex Belianinov
Tuesday PM, November 28, 2017
Hynes, Level 2, Room 201
9:00 AM - *TC03.01.01
Precision Milling and Drilling with a Light Ion Beam
John Notte 1 , Deying Xia 1
1 , Carl Zeiss Microscopy, Peabody, Massachusetts, United States
Show AbstractOne of the great virtues of ions beams (compared e-beam or photonic instruments) is their ability to modify the sample in useful ways by direct momentum transfer. With the advent of highly focused ion beams with sub-10 nm probe sizes, precision milling and drilling of thin membranes becomes possible. There are several unique applications that are gaining increased attention such as biomolecule detection [1]. The ORION NanoFab by Zeiss offers a very small focused probe size (0.5 nm) in combination with low mass ion species at intermediate energies (10 to 35 keV). This combination is well suited for the patterning thin samples such as boron nitride, silicon nitride, graphene, amorphous carbon, silicon, and silicon dioxide.
This talk will provide a review of the instrument’s capabilities such as the ion beam’s small focused probe size, the precision beam control, and the software for automation. Attention will also be given to the physics of the material removal (sputtering) process for the special case of light ions. For light ions, at sufficiently high energies, the beam stays relatively collimated as it penetrates into the sample. This allows the material to be removed with much higher precision and efficacy than could be attained by alternative methods. Modeling results will be presented to provide some insights into the nanoscale material removal process, and factors determining material removal rate. Experimental results demonstrate the scaling with beam parameters (such as total dose, areal dose, defocus) and the time evolution of the pore diameter.
[1] Precise Fabrication of 5nm Graphene Nanopores with a Helium Ion Microscope for Biomolecule Detection. Y. Deng, Q. Huang, Y. Zhao, D. Zhou, C. Ying and D. Wang, Nanotechnology 28, 045302 (2017).
9:30 AM - *TC03.01.02
Scaling the Focused Ion Beam for Applications in Semiconductors
Shida Tan 1
1 , Intel Corporation, Santa Clara, California, United States
Show AbstractThe various phases of the Moore’s Law or the semiconductor performance scaling in the past 52 years has transformed the planet. This trend will continue into the future through not only the traditional transistor density scaling, but also heterogeneous integration and computing architectural innovations. Focused Ion Beam (FIB) is used broadly in the semiconductor industry for a wide range of applications. The scaling of the Moore’s Law poses increasing challenges for FIB applications with smaller critical device dimensions, thinner process layers, densely packed structures, and complex device routing and design architecture. In this paper, we will discuss FIB scaling directions with emphasis on alternative ion beam technologies to gallium Liquid Metal Ion Source (LMIS). The imaging and nanomachining attributes of the helium and neon Gas Field Ionization Source (GFIS) technology and their unique applications in the areas of circuit edit, failure analysis, fault isolation, yield analysis, and mask repair will be discussed in this paper. Trade-offs between various beam parameter to enable successful implementation, challenges of the existing technologies, and the requirements for future instrumentation development will be discussed.
TC03.02: Ion Imaging, Milling and Shaping
Session Chairs
Frances Allen
Alex Belianinov
Tuesday PM, November 28, 2017
Hynes, Level 2, Room 201
10:30 AM - *TC03.02.01
FIB Preparation of Polymer TEM Samples
Andrew Minor 1 2
1 , University of California, Berkeley, Berkeley, California, United States, 2 , Lawrence Berkeley National Laboratory, Berkeley, California, United States
Show AbstractFocused ion beam (FIB) instruments have proven to be an invaluable tool for transmission electron microscopy (TEM) sample preparation. FIBs enable relatively easy and site-specific cross-sectioning of different classes of materials. However, damage mechanisms due to ion bombardment and beam heating effects in materials limit the usefulness of FIBs for soft materials such as polymers. This talk will discuss strategies for limiting beam damage during FIB-preparation of soft materials. Methods of limiting damage that will be discussed include ion species, beam parameters, and cryogenic milling.
11:00 AM - TC03.02.02
Understanding and Controlling Dynamics of Graphene Milling Process Using Helium Ion Beam
Songkil Kim 1 , Anton Ievlev 1 , Ivan Vlassiouk 1 , Matthew Burch 1 , Ondrej Dyck 1 , Xiahan Sang 1 , Raymond Unocic 1 , Alex Belianinov 1 , Sergei Kalinin 1 , Stephen Jesse 1 , Olga Ovchinnikova 1
1 , Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States
Show AbstractAbstract
Graphene has been under intense exploration owing to its excellent electronic, mechanical and thermal properties. This two-dimensional material allows controlled modification of structural, electronic and chemical properties, which can be utilized to design new functional devices. Advances in ion beam-based “direct-write” nanofabrication techniques have provided a tool to precisely manipulate materials and develop new types of high-performance electronic devices. Helium ion microscope (HIM) offers “direct-write” capabilities, packaged in a machine capable of both imaging and nanofabrication, thus making it an excellent candidate for processing of 2D materials. However, despite graphene’s excellent properties and existing tools to take advantage of them, there are still challenges to overcome in the development of a high-performance graphene electronic device using the “direct-write” lithographic technique. An example is the minimization of damage on edges and basal planes of graphene during the milling process to fabricate a graphene device. As such, in-depth understanding of the graphene milling process is necessary.
In this study, we explore graphene milling by helium ion beam in order to take advantage of the underlying milling mechanisms to control electronic and mechanical properties of this material. We demonstrate the localized formation, growth and coalescence of nanopores, by investigating different levels of atomic-to-nanoscale defects in graphene using Raman spectroscopy and Scanning Transmission Electron Microscopy. Using advanced image data analytics, we illustrate the different dynamic behaviors of graphene milling depending on the material’s initial conditions. This work provides in-depth understanding of the graphene milling process, which will be used as a foundation to develop new pathways for manufacturing 2D material based electronic devices.
Acknowledgement
This work was conducted at the Center for Nanophase Materials Sciences (CNMS), which is a U.S. Department of Energy (DOE) Office of Science User Facility.
11:15 AM - TC03.02.03
Laser-Assisted Nanofabrication in the Helium Ion Microscope
Michael Stanford 1 , Kyle Mahady 1 , Brett Lewis 1 , Jason Fowlkes 1 2 , Shida Tan 3 , Richard Livengood 3 , Gregory Magel 4 , Thomas Moore 4 , Philip Rack 1
1 , Univ of Tennessee, Knoxville, Tennessee, United States, 2 Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States, 3 , Intel Corporation, Santa Clara, California, United States, 4 , Waviks Inc, Dallas, Texas, United States
Show Abstract
Focused helium ion (He+) processing has been demonstrated as a high-resolution nanopatterning technique; however, it can be limited by issues such as low sputter yield as well as the introduction of undesired subsurface damage. Here, we introduce a variety of pulsed laser-assisted He+ nanoprocessing techniques which demonstrate notable enhancement over standard He+ processing. These laser-assisted processing techniques are enabled due to the development of the multi-wavelength laser delivery system which mounts on a high-angle port of the helium ion microscope. First, a synchronized infrared pulsed laser is used to demonstrate the in situ mitigation of subsurface damage induced by He+ ion exposures in silicon. The pulsed laser assist provides highly localized in situ photothermal energy which reduces the implantation and defect concentration by greater than 90%. A pulsed laser-assisted He+ milling process is also shown to enable high-resolution milling of titanium while reducing subsurface damage in situ. Finally, a pulsed laser-assisted and gas-assisted focused ion beam induced etching process is shown to increase the etch yield by ∼9× relative to the pure He+ sputtering process. The laser-assisted processing techniques expand the capabilities of focused He+ processing thus extending the applicability of the He+ probe as a nanopattering tool.
11:30 AM - TC03.02.04
Preparation of Silicon Nitride Phase Plates Using Focused Ion Beams
Alexander Müller 1 , Karen Bustillo 1 , Frances Allen 1 2 , Andrew Minor 1 2 , Colin Ophus 1
1 , Lawrence Berkeley National Laboratory, Berkeley, California, United States, 2 Department of Materials Science and Engineering, University of California, Berkeley, California, United States
Show AbstractIn the last few years, several research groups have worked on using phase plates to shape the electron beam of transmission electron microscopes (TEM), achieving results as diverse as vortex beams [1], phase contrast scanning TEM (STEM) [2], and spherical-aberration corrected STEM [3]. Phase plates are often machined using focused ion beam (FIB) microscopes, which have a high precision and allow fast preparation at a comparatively low cost. However, optimizing the fabrication can be challenging and time-consuming, as the resulting phase plate must fulfill several requirements. As the phase shift strongly depends on the thickness of the material, precise thickness control is required over comparatively large areas of hundreds of square micrometers. Furthermore, sharp, well-defined features are desirable. The fabrication is complicated by the strain inherent to the silicon nitride membranes commonly used, and milling can distort the membrane, moving it out-of-plane and even causing ruptures. Yet another concern is ion implantation, which changes the scattering coefficient of the material and thereby the induced phase shift. Lastly, the resulting phase plate should be as thin as possible to minimize high-angle scattering of the electron beam [4].
In this work, we investigated the influence of several milling parameters on the resulting patterns. Test squares were milled into silicon nitride membranes using the Ga-beam of a FIB microscope. Stream files were generated using custom code and allowed directly addressing the digital-to-analog converter. The resulting test patterns were then imaged by optical microscopy and by TEM, thickness maps were acquired by energy-filtered TEM (EFTEM), and Ga-implantation was measured using electron-dispersive X-ray spectroscopy (EDS). Using these methods, we investigated the effect of mill order, beam current, mill time, and number of repetitions on thickness, surface roughness, sharpness of features, and Ga implantation. We further analyzed the stability of the membrane by testing how far it can be thinned at different locations. We thereby optimize the milling parameters for the preparation of phase plates using FIB, and hope that the insights gained by our work will aid the research community in efficiently preparing high-quality phase plates.
[1] M. Uchida and A. Tonomura, Nature 464, 737 (2010).
[2] C. Ophus et al., Nature Communications 7, 10719 (2016).
[3] R. Shiloh et al., arXiv:1705.052321 (2017).
[4] T.R. Harvey et al., New Journal of Physics 16, 09303 (2014).
11:45 AM - TC03.02.05
Patterning Strategies for Large Area and Continuous FIB Nanofabrication Based on Precise Stage Movement
Sven Bauerdick 1 , Achim Nadzeyka 1 , Bjoern Wittmann 1 , Joel Fridmann 2 , Joe Klingfus 2 , Michael Kahl 1
1 , Raith GmbH, Dortmund Germany, 2 , Raith America Inc., Islandia, New York, United States
Show Abstract
Focused ion beam (FIB) systems are applied to an increasing number of applications in R&D nanofabrication. As a result, more advanced and sophisticated patterning approaches also become increasingly important [1,2]. FIB nanofabrication provides direct, resistless, and three-dimensional patterning and is partnered due to these complementary strengths with other lithography techniques. There are also opportunities to transfer instrument solutions and patterning strategies from one discipline to the other, for instance, apply EBL techniques to FIB nanofabrication. We show that with a lithography-centric instrument design in architecture and components it has been possible to employ write field stitching as well as truly continuous, i.e. stitch-free, writing to FIB nanofabrication, after optimization of parameters that are unique to milling as compared to resist-based EBL.
Besides investigation, patterning optimization and application examples for stitching with FIB milling we report on a patterning methodology with a truly continuous stage movement while milling/ cutting with an ion beam. This allows for the creation of continuous structures which can extend for mm or even cm. A high speed pattern generator is synchronized to the movements of the laser-interferometer stage while the beam movement is optimized, e.g. in order to prevent re-deposition. We tested different beam strategies and found that simple beam patterns (which are suitable for EBL) result in V shaped grooves with a lot of re-deposited material (Figure 1), but an improved beam pattern needs to mimic the looping strategy of conventional milling. Optimal patterns are calculated with respect to stage speed, beam current, desired depth, and looping strategy. The result is shown in Figure 2 for grooves with defined depth and steep walls keeping re-deposition to a minimum.
Finally, the same instrumentation can be employed for continuous stripe-like patterning over larger areas with various more sophisticated, repetitive, beam movements (Figure 3). As FIB milling is a quite slow patterning technique compared to EBL, this approach is better-suited for resist, functionalization and implantation applications. Examples for hard masking with Ga in diamond [3] or silicon samples and especially with ions like Au or Si [4,5] will be presented and discussed. In general, the results show that with instrument optimization stitching as well as continuous writing strategies can be successfully applied to direct FIB milling as well as FIB masking and functionalization applications. This will bring advances in optical or fluidic applications which are exceeding a single write field [3].
TC03.03: Ion Microscopy and Secondary Ion Mass Spectrometry
Session Chairs
Tuesday PM, November 28, 2017
Hynes, Level 2, Room 201
1:30 PM - *TC03.03.01
SIMS Performed on the Helium-Ion Microscope—New Prospects for Highest Spatial Resolution Imaging and Correlative Microscopy
Jean-Nicolas Audinot 1 , Florian Vollnhals 1 , Patrick Philipp 1 , Santhana Eswara 1 , David Dowsett 1 , Tom Wirtz 1
1 Material Research & Technology, Luxembourg Institute of Science and Technology, Belvaux Luxembourg
Show AbstractIn order to add nano-analytical capabilities to the Helium Ion Microscope (HIM), we have developed a Secondary Ion Mass Spectrometry (SIMS) system specifically designed for the Zeiss ORION NanoFab HIM [1-2]. SIMS is based on the generation and identification of characteristic secondary ions by irradiation with a primary ion beam. It is an extremely powerful technique for analysing surfaces owing in particular to its excellent sensitivity (detection limits down to the ppb are possible, so that SIMS can be used to detect both major and trace elements), high dynamic range (a same signal can be followed over several orders of magnitude), and ability to differentiate between isotopes.
In SIMS, the typical interaction volume between the impinging ion beam and the sample is around 10 nm in the lateral direction. As the probe size in the HIM is substantially smaller (both for He and Ne), the SIMS lateral resolution on the integrated HIM-SIMS is limited only by fundamental considerations and not, as is currently the case on commercial SIMS instruments, the probe size [2,3]. We have demonstrated that our instrument is capable of producing elemental SIMS maps with lateral resolutions down to 12 nm [2-4]. Furthermore, HIM-SIMS opens the way for in-situ correlative imaging combining high resolution SE images with elemental and isotopic ratio maps from SIMS [2,3]. This approach allows SE images of exactly the same zone analysed with SIMS to be acquired easily and rapidly, followed by a fusion between the SE and SIMS data sets. Moreover, with the SIMS add-on, it is now possible to follow the chemical composition in real time during nano-patterning in the HIM for applications such as end-pointing.
In this talk, we will present a number of examples taken from various fields of materials science (battery materials, solar cells, micro-electronics, coatings, multilayers) and life science (nanoparticles in creams and biological tissues) to show the powerful analytical capabilities and correlative microscopy possibilities enabled by the integrated HIM-SIMS instrument.
[1] T. Wirtz, N. Vanhove, L. Pillatsch, D. Dowsett, S. Sijbrandij, J. Notte, Appl. Phys. Lett. 101 (4) (2012) 041601-1-041601-5
[2] T. Wirtz, D. Dowsett, P. Philipp, Helium Ion Microscopy, edited by G. Hlawacek, A. Gölzhäuser, Springer, 2017
[3] T. Wirtz, P. Philipp, J.-N. Audinot, D. Dowsett, S. Eswara, Nanotechnology 26 (2015) 434001
[4] P. Gratia, G. Grancini, J.-N. Audinot, X. Jeanbourquin, E. Mosconi, I. Zimmermann, D. Dowsett, Y. Lee, M. Grätzel, F. De Angelis, K.Sivula, T. Wirtz, M. K. Nazeeruddin, J. Am. Chem. Soc. 138 (49) (2016) 15821–15824
2:00 PM - TC03.03.02
3D Chemical Analysis of Inorganic and Organic Nanostructures Using ToF-SIMS and In Situ SPM
Ewald Niehuis 1 , Rudolf Moellers 1 , Felix Kollmer 1 , Derk Rading 1 , Henrik Arlinghaus 1 , Nathan Havercroft 2 , Adi Scheidemann 3
1 , ION-TOF GmbH, Muenster Germany, 2 , ION-TOF USA Inc., Chestnut Ridge, New York, United States, 3 , Nanoscan AG, Duebendorf Switzerland
Show AbstractTOF-SIMS is known to be an extremely sensitive surface analysis technique which provides elemental as well as comprehensive molecular information on any kinds of solid surfaces. A high lateral resolution down to 20 nm can be achieved using Bismuth liquid metal ion guns [1]. In combination with conventional low energy oxygen or cesium sputtering, 3D structures can be analysed with a high lateral resolution and a depth resolution in the nm range. With the advent of large gas cluster ion beams (GCIB) [2], the 3D capability of the TOF-SIMS was extended to complex organic materials and devices [3]. Inherent to all 3D SIMS data is a z-axis with a native time scale instead of a length scale. A starting topography of the initial sample surface as well as an evolving topography due to different sputter rates of the compounds cannot be identified by the technique and lead to major distortions of 3D data sets. The sputter rates of the various inorganic and organic materials are very different in particular for large gas cluster sputtering [4] and can be strongly influenced by radiation damage of organic materials.
We integrated a Scanning Probe Microscope (SPM) unit into a ToF-SIMS instrument. The SPM provides the required complementary information on the surface topography down to the nanometer level. Beyond that, SPM yields valuable information on physical properties if the cantilever is operated in the appropriate dynamic operation modes (e.g. KPFM, conductive AFM, MFM). The core piece of the new instrument is a piezo driven stage which moves the sample between the TOF-SIMS and the SPM analysis position with high precision and speed. The SPM unit is mounted on a 3-axis linearized flexure stage scanner with a very small out-of-plane motion and a scan range of 80 x 80 x 10 µm3. The SPM is also required to measure the sputter crater depth with high precision. For crater sizes of several hundred µm, a special long distance surface profiler mode was developed to measure the correct shape and depth of the sputter crater.
In this paper we will describe the instrument capabilities and present various examples highlighting the strength of this novel combined instrument and its potential for a wide range of applications. Examples include the characterization of semiconductor devices, SOFC, OLED as well as biological single cells.
[1] F. Kollmer, W. Paul, M. Krehl and E. Niehuis, Surf. Interface Anal. 45, (2013) 312
[2] S. Ninomiya, K. Ichiki, H. Yamada, Y. Nakata, T. Seki, T. Aoki and J. Matsuo,
Rapid Commun. Mass Spectrom. 23, 3264 (2009)
[3] E. Niehuis, R. Moellers, D. Rading, H.-G. Cramer, R. Kersting, Surf. Interface Anal. 45, (2013) 158
[4] M.P. Seah, J. Phys. Chem. C, 2013, 117(24), pp 12622-12632
2:15 PM - TC03.03.03
Ion Beam Based Approach for Thin Films Thinning and Cleaning
Anton Ievlev 1 , Marius Chyasnavichyus 1 , Donovan Leonard 1 , Lane Martin 2 , Sergei Kalinin 1 , Petro Maksymovych 1 , Olga Ovchinnikova 1
1 , Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States, 2 , University of California, Berkeley, Berkeley, California, United States
Show AbstractThe ability to control thin-film growth has led to advances in our understanding of fundamental physics as well as to the emergence of novel technologies. Processing techniques that allow for monolayer precision control during the growth process like pulsed-laser deposition (PLD) and atomic-layer deposition (ALD) grow materials in accordance with fundamental physics and allow for only certain terminations at the film interface and surface. Additionally, when using these approaches dislocations and vacancies will migrate to the film interface causing problems for controlling the chemistry of the interface as well as leading to surface instabilities and contamination. Altogether, these factors limit the scope of systems we can produce and study experimentally.
Here we open a new direction for research in complex oxides by demonstrating a subtractive fabrication process that enables creation and modification of thin films with pre-defined thicknesses. It allows us to elucidate the properties of oxides while simultaneously minimizing the effects of contaminants. We apply a combination of Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) with Atomic Force Microscopy (AFM) for precise sputtering of the nanometer-thin layers of material. The sputtering process is realized by the ion beam under control of mass spectrometry. AFM is further utilized for sputtering depth calibration. To verify this technique, we systematically investigated systematic thickness dependence of ferroelectric switching of lead-zirconate-titanate, with just one epitaxial film. Surprisingly, we observe not only robust switching in pre-sputtered films, but also strong improvement of piezoelectric response once the aged surface layer is removed.
This work was conducted at the Center for Nanophase Materials Sciences, which is a Department of Energy (DOE) Office of Science User Facility.
2:30 PM - *TC03.03.04
Multimodal Chemical Imaging of Nanoscale Interfacial Phenomena on a Combined HIM-SIMS Platform
Olga Ovchinnikova 1
1 , Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States
Show AbstractThe key to advancing energy materials is to understand and control the structure and chemistry at interfaces. However, significant gaps hamper chemical characterization available to study and fully comprehend interfaces and dynamic processes; partly due to the lack of breadth of necessary information, as well as its scattered nature among a multitude of necessary measurement platforms. Multimodal chemical imaging transcends existing analytical capabilities for nanometer scale spatially resolved interfacial studies, through a unique merger of advanced helium ion microscopy (HIM) and secondary ion mass spectrometry (SIMS) techniques. In this talk I will discuss how to visualize material transformations at interfaces, to correlate these changes with chemical composition, and to distil key performance-centric material parameters using a multimodal chemical imaging approach on a combined HIM-SIMS system. Particular attention will be focused on how to use the HIM-SIMS to study the role of ionic migration on the photovoltaic performance, or alternatively whether the ionic migration plays a positive or negative role in determining superior photovoltaic performance in organic-inorganic perovskites (HOIPs). I will discuss how synthesizing perovskite on custom substrates effect active chemical agents in materials and understand how interfaces in materials affect the local chemistry, specifically, key energy related parameters such as electron and ion motion and their re-distribution. Overall, multimodal chemical imaging on a combined HIM-SIMS platform offers the potential to unlock the mystery of active interface formation through intertwining data analytics, nanoscale elemental characterization, with imaging; to better grasp the physical properties of materials and the mechanistic physics-chemistry interplay behind their properties.
Acknowledgements
This work was conducted at the Center for Nanophase Materials Sciences, which is a Department of Energy (DOE) Office of Science User Facility
TC03.04: Material Property Mapping and Ion Transmission
Session Chairs
Tuesday PM, November 28, 2017
Hynes, Level 2, Room 201
3:30 PM - *TC03.04.01
Structuring Magnetic and Electronic Materials Using GFIS Noble Gas Focused Beams
Gregor Hlawacek 1
1 , Helmholtz Zentrum Dresden Rossendorf, Dresden Germany
Show AbstractNew device concepts envisioned to solve some of the pressing problems in todays computing technology require new methodological approaches --both for manufacturing but also during initial research. In this presentation I want to highlight the potential and limitations of ion beams and in particular gas field ion source based (GFIS) noble gas beams for this demanding development process.
In an first example I want to present results of low fluence ion beam structuring of alloys with interesting magnetic properties such as FeAl. This material undergoes a phase transition upon ion irradiation that converts the initially paramagnetic material into a ferromagnetic one. Using the highly localized irradiation possible in the helium ion microscope and low fluencies of only 1-5 Ne per nm2 we can locally change the properties and thus create arbitrary shaped nano magnets. The fundamental properties of these electron spin controlling structures with critical dimensions as small as 20 nm can be studied by TEM holography or scanning transmission x-ray microscopy.
Other device concepts require the control of currents at the single electron level. In the second part of the talk I will present first results of the realization of a CMOS compatible single electron transistor (SET) that works at room temperature (RT). We employ a focused GFIS Ne beam to locally mix silicon into a thin silicon dioxide
layer. During a subsequent thermal treatment a single silicon cluster with a diameter of only 2-3 nm forms in the oxide. The cluster is separated from the surrounding silicon by only 2 nm providing optimum tunnel distances for RT SET operation. This process is based on the small size of collision cascade in the HIM. A more CMOS compatible restriction of the mixed volume can be achieved by using broad beam irradiation and nano-pillars. The first is a well established technique in semiconductor fabrication and latter can be mass fabricated using
advanced lithography. In the so achieved restricted mixed volume a single cluster forms during the subsequent annealing.
Both examples highlight the flexibility of the GFIS technique and its potential for the rapid prototyping of new device concepts based on ion beam techniques.
This work has been partially funded by the European Union’s Horizon 2020 Research and Innovation Program under grant agreement No. 688072 “IONS4SET”.
4:00 PM - TC03.04.02
Scanning Transmission Helium-Ion Microscopy with a Dedicated Detector
Taylor Woehl 1 , Ryan White 2 , Robert Keller 2
1 , University of Maryland, College Park, Maryland, United States, 2 , National Institute of Standards and Technology, Boulder, Colorado, United States
Show AbstractHere we employ a multichannel plate as a helium ion sensitive transmission detector in a commercial helium ion microscope for annular dark-field imaging of nanomaterials, i.e. scanning transmission helium ion microscopy. In contrast to previous transmission helium ion microscopy approaches that used secondary electron conversion holders, our new approach detects transmitted helium ions with a dedicated annular detector. Monte Carlo simulations are used to predict detector collection angles at which annular dark-field images with atomic number contrast are obtained. We demonstrate atomic number contrast imaging via scanning transmission ion imaging of silica-coated gold nanoparticles and magnetite nanoparticles and explain collection angle dependent contrast inversion. The large elastic scattering cross-section of helium ions and potential for optimization of the multichannel plate detector to provide high-sensitivity suggests applications for imaging low-contrast 2D materials. We expect this new approach to scanning transmission ion microscopy will open avenues for more quantitative ion imaging techniques, such as direct mass-thickness determination, and advance fundamental understanding of underlying ion scattering mechanisms leading to image formation.
4:15 PM - TC03.04.03
Transmission Images of He Ion-Beam Milling and Channeling through Thin Si Membranes
Karen Kavanagh 1 , Christoph Herrmann 1 , Jiaming Wang 1 , Symphony Huang 1 , Shelley Scott 2 , Max Lagally 2
1 , Simon Fraser University, Burnaby, British Columbia, Canada, 2 , University of Wisconsin, Madison, Wisconsin, United States
Show AbstractHelium ion channeling and blocking (MeV energies) in backscattering geometries are well known methods for the detection of point defects in crystalline materials. Lower-energy focussed-He ion beams (15 - 40 keV) are also known to channel based on contrast visible in secondary electron images, generated while scanning the He beam over the sample surface. Since the resolution of such images is less than 1 nanometer, the potential for using He channeling intensities as a local probe of point defects in thin samples is intriguing. We have been experimenting with a digital camera for the direct detection of He ions transmitted through thin Si membranes. The camera consists of an array of Si p-i-n diodes (55 μm square pixels) located below the sample stage and tilt cradle in our He ion microscope (Zeiss Nanofab). We will present transmission scattering images and peak intensity profiles, comparing amorphous to single-crystalline Si membranes (25 nm - 75 nm thick) as a function of beam energy and tilt angle. Planar channeling is detected with critical angles of 1° (25 kV), as predicted by the Lindhard continuum model. Milling rates are affected by channeling with nanoscale holes forming faster in amorphous membranes.
Acknowledgements: Norcada Inc. (Edmonton) for supplying Si (100) 50 nm thick membranes; NSERC, CFI/BCKDF, 4DLABs for funding.
4:30 PM - TC03.04.04
Evidence form Low Temperature RBS-Channeling Study of Structural Phase Transition in the Incoherent Lattice Fluctuations, Lattice Distortion and Local Microstructure of Pure and Implanted SrTiO3
Kalyan Sasmal 1 , Wei-Kan Chu 1
1 Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, Texas, United States
Show AbstractLow temperature Rutherford Backscattering Spectrometry Axial Ion Channeling ( 2.0 MeV He+ ), ultrafast real-space probe of sub-picometre atomic displacement is used to probe displacive structural phase transition (PT) & Jahn-Teller (JT) lattice distortion in perovskite SrTiO3. It provides direct evidence of incoherent lattice fluctuations (thermal vibrational amplitude) as function of temp across non-ferroelectric (FE) 2nd order antiferrodistortive cubic to body centered tetragonal (O1h→D184h with doubled primitive unit cell) structural PT at Curie-Weiss T0 =105 K, caused by antiphase tilting of TiO6 octahedra , leads to low T quantum paraelectric, by minimizing Gibbs free energy. AFD rotation opens bandgap & weakens FE instability by reducing cross gap hybridization. Defects in semiconducting SrTiO3 narrows large band gap & raises Fermi level into conduction band & ensures conductivity. Depth distributions of implanted (Fe, Cr etc.) derived from XPS peaks intensity, agrees with SRIM simulation. No significant diffusion of Fe/Cr after rapid thermal annealing to 1000°C.JT effect occur for degenerate filled & empty molecular orbitals. Critical channeling angle ψc & ratio of minima of angular RBS-ICh spectral yield χmin for Sr & Ti sublattices determine JT lattice distortion in transition element (Fe, Cr etc.) implanted SrTiO3. Similar values of ψ1/2 for Sr sublattice indicates no displacement of Sr. Absence of peak in minima of angular ICh spectra and distortion of Ti sublattice infers implanted Fe & Cr is actually located in Ti positions but not in interstitial positions. Narrowing of U shaped wells for Ti sublattice suggests Cr & Fe displaces Ti ions from ideal lattice sites. Temp dependence of Thermal vibrational amplitudes (ρ) of Sr & Ti also displacements of Ti4+ are calculated based on Linhard’s continuum model. Change in ρ indicating a dynamic or static displacement of Sr & Ti atoms and sudden decrease of ρ with decreasing temperature due to AFD-PT at T0≈ 105 K, lead to two different regions with different lattice constants. Implanted SrTiO3 shows a minor tetragonal phase corresponds to lattice expansion along c-axis. GID-XRD φ plot shows expected four fold rotation symmetry around [001] axis, indicating minor phase is not randomly oriented. Cr & Fe impurity could induce Raman active localized Oxygen vibrational mode, not involving motion of nearest Fe or Ti ions. TEM Samples for cross sectional microstructure analysis are prepared by FIB milling. Conventional & High-Resolution TEM imaging, Selected Area Electron Diffraction & Energy Dispersive Spectroscopy were used to identify the presence of atomic distortions, defects and local microstructure.
TC03.05: Poster Session: Imaging and Surface Modification by Ion Microscopy
Session Chairs
Wednesday AM, November 29, 2017
Hynes, Level 1, Hall B
8:00 PM - TC03.05.01
Application Method of Sub-Images Extracted for Higher-Resolution Imaging and Images Fussion for Multi-Scale Pore Space Characterization
Yongjie Ma 1 , Xin Wang 1 , Ye Xu 2 , Chaohua Guo 3 , Zhonghai Zhou 1 , Danyong Li 4
1 , Institute of Oceanographic Instrumentation, Shandong Academy of Sciences (SDIOI), Qingdao City China, 2 , Beihang University, Beijing China, 3 , China University of Geosciences (Wuhan), Wuhan China, 4 , OLEUMTECH Co., Ltd, Beijing China
Show AbstractWith development in research of unconventional resources, such as shale-gas and hydrate gas, more and more high-resolution imaging equipment, such as XRD and FIB-SEM, are used to study the phenomenon in micro-structure of pore space, for example the transfer of fluid and heat. A few issues were found during this period, for instance, how to select the proper sub-image from a sample and how to integrate a higher-resolution sub-image into the whole image. Therefore, we proposed a series of solutions based on mathematical and morphological approaches. We got typical sub-sample images for higher resolution imaging by calculating Euler number and connectivity. To keep the original structure of pore space, we used laser to get the relative coordination of sub-images, so that we can integrate them into the whole image accurately again. In the next step, we used pore network modeling method to avoid complex computing. Our solutions have satisfied customers’ demands very well.
8:00 PM - TC03.05.02
Rapid Screening of Nanoporous Structures in SiO2 Catalyst Particles via Helium Ion Microscopy
Matthew Burch 1 , Anton Ievlev 1 , Holland Hysmith 1 , Kyle Mahady 2 , Philip Rack 2 , Lubin Luo 3 , Alex Belianinov 1 , Sergey Yakovlev 3 , Olga Ovchinnikova 1
1 , Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States, 2 , University of Tennessee, Knoxville, Knoxville, Tennessee, United States, 3 , ExxonMobil Chemical Company, Baytown, Texas, United States
Show AbstractNano-porous materials are some of the most important modern materials, as they are utilized extensively in a vast number of applications, from battery and solar cell applications to drug delivery and agriculture. However, despite there importance, the number of techniques to observe and quantify pore shape, size, and structure remain limited. The most common techniques involve the use of gas absorption, where a gas is absorbed by a material and subsequently desorbed. The rate and amount of absorption, can be fit to different models and salient parameters, such as pore volume and size, can be extracted. However, despite gas absorption being the industry standard technique, it has some fundamental drawbacks which include the speed at which a sample can be analyzed (~1 sample per day) and the inability to directly observe surface pore morphology, which is an integral and important parameter for porous applications.
In this work, we utilize helium ion microscopy (HIM) to rapidly image and quantify the pore structure at the surface of porous SiO2 catalyst precursor particles. HIM has a few significant advantages over traditional scanning electron microscopy (SEM), such as the ease in which non-conductive materials systems can be directly imaged without the need for any kind of conductive coating, which can obscure, and even modify, surface features. The HIM can images these surfaces due to the positive charge of the bombarding helium atom and the application of an electron flood gun to compensate for any positive charging. Through the use of advanced image analytics, the pore structure of the SiO2 particles can be directly observed and quantified. We then compare our results to the industry standard gas absorption and demonstrate that our results agree within 5% of the gas absorption technique for a commercially available sample. Further, to understand the surface interaction between the HIM and the SiO2 particles, we utilized advanced ion-matter interaction software that demonstrates that at low ion dosages, the surface of the SiO2 particle is negligibly modified during imaging.
Acknowledgements
Research was supported and conducted at the Center for Nanophase Materials Sciences, which is sponsored at Oak Ridge National Laboratory by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy. The authors acknowledge the ExxonMobil Chemical Company for support.
8:00 PM - TC03.05.03
Two-Dimensional Circuitry Achieved by Defect Engineering of Transition Metal Dichalcogenides with the Helium Ion Microscope
Michael Stanford 1 , Pushpa Pudasaini 1 , Anna Hoffman 1 , Philip Rack 1
1 , Univ of Tennessee, Knoxville, Tennessee, United States
Show Abstract
Two-dimensional materials, such as transition metal dichalcogenides (TMDs), have demonstrated promising semiconducting properties. The electrical and optical properties of TMDs can be fined tuned by altering material thickness as well as chemical composition. Properties can also be tuned by defect engineering. In this work, a focused He+ beam as well as a remote plasma source were utilized to introduce defects into TMDs such as WSe2 and WS2. High spatial resolution as well as fine control of energetic He+ conditions enable defects to be directly-written with control over the defect concentration. Scanning transmission electron microscopy reveals that defects introduced into the TMDs range from chalcogen vacancies (0D defects) to 1D defects and extended defect networks. Tailoring defect concentration enables tunability of the electronic properties with insulating, semiconducting, and metallic behavior each obtainable. By tuning electronic properties, we demonstrate direct-write logic gates such as resistor loaded invertors with a voltage gain of greater than 5. We also demonstrate the fabrication of edge-contacted field effect transistors by defect engineering homojunctions between metallic and semiconducting WSe2 with on/off ratios greater than 106. Defect engineering of TMDs enables the direct-write of complex devices into single flakes toward the goal of atomically thin circuitry.
8:00 PM - TC03.05.04
Luminescence Tuning in BiFeO3 (BFO) Thin Films by Swift Heavy Ion Irradiation
Balram Tripathi 1 2 , Manoj Kumar 3 , Rajesh Katiyar 1 , F Singh 4 , K.B. Sharma 2 , Ram S Katiyar 1
1 Physics, University of Puerto Rico, San Juan, Puerto Rico, United States, 2 Physics, S S Jain Subodh PG (Autonomous) College, Jaipur, Rajasthan, India, 3 Physics, Malviya National Institute of Technology, Jaipur, Rajasthan, India, 4 Material Science, Inter University Accelerator Centre Aruna Asaf Ali Marg, New Delhi India
Show AbstractBiFeO3 (BFO) has attracted extensive research as an excellent multiferroic material. The structural, electronic, optical and photoluminescence properties of bismuth ferrite (BiFeO3) thin films deposited by pulse laser deposition on Si(100) substrate were investigated. X-ray diffraction pattern reveals a well grown epitaxial BFO thin film. Atomic force microscopy study confirms that BFO film is dense with smooth surface. By swift heavy ion (SHI) irradiation it is possible to modify structural strain in films which tunes the optical luminescence, electrical and magnetic properties. The dependence of luminescence, on deposition temperature, pressure and SHI irradiation fluence will be discussed.
8:00 PM - TC03.05.05
Ion Beam Induced Current Measurements with Helium Ion Microscopy
Alex Belianinov 1 , Songkil Kim 1 , Ryan Buechley 1 , Matthew Burch 1 , Olga Ovchinnikova 1 , Stephen Jesse 1
1 , Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States
Show AbstractThe scanning electron microscope (SEM) is a versatile high-resolution microscopy tool, and perhaps the most widely used imaging platform across many engineering and scientific fields. Within the last decade, another microscopy technique based on a gaseous field ionization source, utilizing Helium and Neon ions has been introduced. While the popularity of the SEM is hardly challenged by the Helium Ion Microscopy (HIM), there are instances when imaging with ions offers significant advantage as opposed to imaging with electrons. In principle, both HIM and the SEM share many similarities, for example, a HIM operating at 40 keV will generate ions with velocity comparable to SEM operating at 5 keV. However, due to much higher stopping power of ions, as compared to electrons, ion based secondary electron (iSE) will be higher. Also, as a result, there is little ion backscattering, and consequently, the concentration of the ion-generated iSE2 (additional secondary electron generated by SE interaction within the material) is usually insignificant.
In this work, we exploit small interaction volumes in the HIM, and take advantage of the lower iSE2 yield, and positively charged helium ions to map ion beam induced current (IBIC) in solar cell materials. Similar studies, using electrons, have visualized induced current profiles at grain profiles in polycrystalline solar cells, and in silicon. Furthermore, broad ion sources have been utilized in conjunction with scanning probe systems in the past to map out current changes in FinFETs. We are interested in utilizing the HIM to map current at the nanoscale near p-n junctions in CdTe to elucidate differences in contrast captured by the ion beam induced current, as opposed to the electron beam induced current. These findings will illustrate the peculiarities of ionic transport in these solar cell materials, and will evaluate the HIM technology as a potential quality control tool.
Symposium Organizers
Alex Belianinov, Oak Ridge National Laboratory
Frances Allen, University of California, Berkeley
Shinichi Ogawa, National Institute of Advanced Industrial Science and Technology
Tom Wirtz, Luxembourg Institute of Science and Technology (LIST)
Symposium Support
Raith America, Inc.
ZEISS Microscopy
TC03.06: Electron and Ion Induced Deposition
Session Chairs
Frances Allen
Alex Belianinov
Wednesday AM, November 29, 2017
Hynes, Level 2, Room 201
9:00 AM - *TC03.06.01
Mechanism-Based Design of Precursors for FEBID
Lisa McElwee-White 1
1 , University of Florida, Gainesville, Florida, United States
Show AbstractFocused electron beam induced deposition (FEBID) can create metal-containing nanostructures by using electrons to induce local decomposition of organometallic precursors. For FEBID to emerge as a broadly applicable nanofabrication technique, however, control must be exerted over not just the size and shape, but also the chemical composition of the nanostructures. The common practice has been to use precursors designed for thermal processes, such as chemical vapor deposition (CVD). Unfortunately, organometallic precursors that yield pure metal deposits in CVD generally create FEBID deposits with high levels of organic contamination. We are using mechanistic insights from surface science and gas phase electron-molecule interactions to design organometallic precursors specifically for FEBID. Synthesis of the candidate precursor complexes and evaluation of their electron-induced reactivity under UHV and steady state deposition conditions allow us to identify privileged ligands for use in FEBID. Examples to be discussed include (η3-C3H5)Ru(CO)3X, cis-Pt(CO)2X2, and CF3AuCNR where X = halide and R = alkyl.
9:30 AM - *TC03.06.02
Characteristics of Beam Induced Depositions Made with Electrons and H, He, Ga, O or Xe Ions
Johannes Mulders 1
1 , ThermoFisher Scientific, Eindhoven Netherlands
Show AbstractBeam induced depositions are micro and nano scale structures directly created by a precursor decomposition, induced by a focused beam of energetic charged particles that interacts with the sample. The beam can consist out of electrons, such as available in a regular scanning electron microscope (SEM) or out of ions, of which Ga is the most commonly used in a focused ion beam system (FIB). However, recently other types of ions have become available and the deposition characteristic with these ions has been studied as well. Important characteristics are the composition of the actual deposition, in view of the applied precursor and ion species, the process-speed or yield, the micro-structure and of course the main “intended property” of the nano-structure such as conductivity for metal deposition or isolator deposition and magnetic and plasmonic properties of ferro-magnetic materials and gold respectively.
A typical characteristic of ion beam induced deposition as opposed to electron beam induced deposition is the fact that the ion itself is incorporated in the deposition. This can result in implantation, blister formation or, depending on the particle, in additional chemical activity which is similar to adding particles as a purification strategy: the beam ion is part of the chemical reaction mechanism. Due to the overall higher energy of the ion – secondary effects such as scattering resulting in the formation of halo type structures. Finally the ions do have a milling component in the dynamic deposition process and this component can either be neglected, such as for H or has a major influence on the process, such as for Xe. Although oxygen beams are available in most SIMS instrumentation, their applicability for ion beam induced deposition has hardly been studied. Extrapolating from the results from other beams, the characteristic of oxygen for the creation of small scale structures will be estimated.
TC03.07: 3D Structure Fabrication
Session Chairs
Frances Allen
Alex Belianinov
Wednesday PM, November 29, 2017
Hynes, Level 2, Room 201
10:30 AM - *TC03.07.01
The Three-Dimensional Nano- and Microstructure Fabrications by Using Focused Ion Beam
Reo Kometani 1
1 Graduate School of Frontier Sciences, The University of Tokyo, Chiba Japan
Show AbstractFocused-ion-beam chemical vapor deposition (FIB-CVD) is a key technology in order to achieve the three-dimensional (3-D) nano- and microstructure fabrication. Bottom up fabrications of the 3-D nano- and microstructures are performed by precisely controlling the irradiation position and time of FIB under the atmosphere of source gas. We have researching on FIB-CVD in order to realize various 3-D nanodevices. Thus far, growth characteristics of the 3-D nanostructure, a pattern generator for precise fabrication, material characteristics and device fabrications had been studied.
The pattern generator had been developed by evaluating growth characteristics of the 3-D nanostructure. We found that it is possible to detect the growth angle of nanostructure by monitoring secondary electron intensity and substrate current during fabrication. And, the pattern generator which enables the real-time control of growth shape was developed. We demonstrated that the fabrication of ultra-long overhang structures by the real-time control of the irradiation time of FIB using this pattern generator.
Material characteristics of the nanostructures fabricated by FIB-CVD were evaluated. As a result, diamond-like carbon (DLC) structure could be deposited by using phenanthrene as a gas source. And nanostructure made of DLC had superior mechaniacal characteristics. Furthermore, we found that DLC is functionalized as a piezoresistive material by annealing treatment.
Furthermore, we demonstrated the various 3-D nano- and microdevices using FIB-CVD. As an application of FIB-CVD, nanomechanical devices had been developed. Fabrication of a nanomanipulator as a mechanlcal device was studied. Nanomanipulator with the 3-D finger structure was useful to manipulate the nanoparts. Moreover, an optomechanical resonator with the 3-D plasmonic structure for wavelength detection was fabricated by using FIB-CVD. High resolution wavelength measurement of 2.2 pm was achieved. FIB-CVD is a powerful tool to carry out researches various functional devices. The 3-D nano- and microstructure fabrications by FIB-CVD and its applications will be reported in detail.
11:00 AM - TC03.07.02
Focused Ion Beam Induced Deposition of Complex Nanoscale 3D-Structures via Helium Ion Beam Irradiation
Matthew Burch 1 , Anton Ievlev 1 , Michael Stanford 2 , Brett Lewis 2 , Xiahan Sang 1 , Songkil Kim 1 , Jason Fowlkes 1 , Philip Rack 2 , Raymond Unocic 1 , Alex Belianinov 1 , Olga Ovchinnikova 1
1 , Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States, 2 , University of Tennessee, Knoxville, Knoxville, Tennessee, United States
Show AbstractThe ability to fabricate free-standing complex metallic structures at the nano-scale has the ability to impact a variety of fields, from nano-lithography to the construction of bacterial “lobster traps.” Much work has been dedicated to this work, with a variety of fabricating techniques, from two-beam photon lithography to in-situ liquid growth techniques being utilized. In particular, focused electron beam induced deposition (FEBID), has stood out as a superior technique, which can create free-standing structures at the nano-scale. Recently, Fowlkes, et. al. developed advanced electron-precursor simulations that allow the prediction and subsequent construction of very complex nano-structures. An alternative to FEBID is focused ion beam induced deposition (FIBID) with helium ion microscopy (HIM). FIBID has several potential advantages over FEBID, including the ability to in-situ mill and subsequently deposit on samples, including 2D material systems. In addition, due to the ability to charge compensate with the use of an electron flood gun, FIBID allows for nano-scale deposition on very insulating materials.
In this work, we utilize the software devised by Fowlkes, et. al. to fabricate complex 3-dimensional structures with FIBID. To understand the various parameters and how they impact the final grown 3D structure, we created a software, which rapidly extracts the growth parameters of branched-grown pillars used to calibrate the software. We analyzed hundreds of pillars to understand the trends by varying the precursor flow rate, beam current, dwell time and pitch. From the parameters, we’ve begun to understand and optimize the grown structures for size and shape. Further, we utilize electron energy loss spectroscopy (EELS) and energy dispersive x-ray spectroscopy (EDS) to understand the chemical nature of the different grown structures.
Acknowledgements
Research was supported and conducted at the Center for Nanophase Materials Sciences, which is sponsored at Oak Ridge National Laboratory by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy.
11:15 AM - TC03.07.03
Growing Nanostructures with Focused Ion Beams
Frances Allen 1 , Alexander Müller 2 , Andrew Minor 1 2
1 Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, California, United States, 2 , Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California, United States
Show AbstractIon-beam-induced deposition (IBID) in a focused ion beam (FIB) microscope is the process by which a gaseous precursor is injected towards the sample and the ion beam is rastered across a region of interest to decompose the precursor molecules resulting in their deposition on the sample surface. The decomposition reaction occurs primarily as a result of interactions with the low-energy secondary electrons that are generated when the ion beam impacts the sample. Gallium IBID is widely used in FIB processes, for example in circuit edit applications or for the deposition of protective layers prior to FIB cross-sectioning. With the advent of the Helium Ion Microscope (HIM), which generates finely focused helium and neon ion beams from an atomically sharp gas field-ionization source, IBID by lighter ion species has now become possible. Due to the nature of the beam-sample interaction, specifically the narrower interaction volume near the sample surface from which secondary electrons are emitted, helium and neon IBID enables direct-write at a higher spatial resolution than gallium IBID. Here, helium, neon and gallium IBID of tungsten and silicon oxide chemistries is investigated. Optimum parameters for deposition by the various ion beams are determined as are the precise elemental compositions of the deposited materials using scanning transmission electron microscopy x-ray energy-dispersive spectrometry (STEM-XEDS). Unique applications of IBID in the HIM will be discussed.
11:30 AM - TC03.07.04
Focused Electron- and Focused-Ion Beam Fabrication of Ultra-Low Power Gas Nanosensors Based on Single Metal-Oxide Nanowires
Jordi Sama 1 2 , Guillem Domènech-Gil 1 2 , J. Daniel Prades 1 2 , Olga Casals Guillen 1 2 , Francisco Hernandez-Ramirez 1 2 , Mauricio Moreno 1 2 , Sven Barth 3 , Albert Romano-Rodriguez 1 2
1 Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona (UB), Barcelona Spain, 2 MIND-Department of Electronics, Universitat de Barcelona, Barcelona Spain, 3 Department of Materials Chemistry, Vienna University of Technology (TUW), Vienna Austria
Show AbstractMonocrystalline defect-free metal oxide nanowires are very interesting material for the fabrication of future sensing devices. For this reason, they have been investigated for more than 20 years. Monocrystalline nanowires offer large surface-to-volume ratio [1,2] and because their surfaces can be well controlled, they can provide quite well-known interaction with gases, allowing basic understanding of gas-solid interactions, which can be potentially exploited for commercially applications. However, a large drawback of such devices is that they need to operate at high temperatures, in excess of 150C, but mostly above 200C and, sometimes, even 300C, to allow adsorption-desorption processes. Furthermore, the fabrication of gas sensing devices based on them is still challenging.
In this work we will present the results of our extensive research in the development of gas sensors based on individual nanowires, carried out over the last 13 years, in which we have used Focused Electron- (FEBID) and Focused Ion-Beam Induced Deposition (FIBID) for the fabrication of gas sensing devices based on individual nanowires. The active materials employed were single crystalline, dislocation free metal oxide nanowires (diameter 40-400 nm), synthesized by chemical vapor deposition (CVD) of molecular precursors [2] grown on ceramic or silicon substrates. The grown nanowires are transferred onto suspended substrates with heater and interdigitated microelectrodes, which require few mW to reach the above-mentioned temperature ranges. The contact fabrication has been achieved by FEBID and FIBID [3].
When using a Source-Measurement Unit (SMU) to measure the resistance variation of the single nanowire when in contact with different gas atmospheres, due to the enhanced local Joule effect, local heating occurs. This can be employed to provide the required operating temperature of the gas sensors without applying external power to the heaters and, consequently, the power demand of such device is reduced to about 20 mW. Based on this approach we have developed a portable detection system that uses a thermoelectric generator to provide the required operating power to both heat and read-out the gas sensing results [4], benefiting from the focused electron and ion technologies.
In this work we will present the state of our almost zero-power gas detection systems based on individual nanowires.
References
[1] S. Barth, F. Hernandez-Ramirez, J.D. Holmes, A. Romano-Rodriguez, Prog. Mater. Sci. 55 (2011) 563.
[2] S. Mathur, S. Barth, H. Shen, J. C. Pyun, U. Werner, Small 1 (2005) 713.
[3] F. Hernandez-Ramirez, A. Tarancon, O. Casals, J. Rodriguez, A. Romano-Rodriguez, J. R. Morante, S. Barth, S. Mathur, T. Y. Choi, D. Poulikakos, V. Callegari, P. M. Nellen, Nanotechnol. 17 (2006) 5577.
[4] J.D. Prades, R. Jimenez-Diaz, F. Hernandez-Ramirez, S. Barth, A. Cirera, A. Romano-Rodriguez, S. Mathur, J.R. Morante, Appl. Phys. Lett. 93 (2008) 123110.
TC03.08: Ion Implantation and Defect Engineering
Session Chairs
Wednesday PM, November 29, 2017
Hynes, Level 2, Room 201
1:30 PM - *TC03.08.01
Helium-Ion Beam Induced Deposition—Combining the Best of Two*?
Paul Alkemade 1
1 , Delft University of Technology, Delft Netherlands
Show AbstractThe recent introduction of the helium ion microscope (HIM) offers new possibilities for materials modification and fabrication with spatial resolution below 10 nm [1]. In particular, the specific interaction of He+ ions in the tens of keV energy range with materials—i.e., minimal deflection, minimal sample erosion by ion sputtering, and mainly energy loss via electronic excitations—renders the HIM a special tool for ion-beam-induced deposition (IBID). This presentation gives an overview is of helium-ion-beam-induced deposition (He-IBID). Continuum models and Monte Carlo models that describe the deposition processes, are discussed and examples of experimental He-IBID studies are presented. It is e.g. shown that deposition takes place only in a small zone around the impact point of the ion beam. Also, the characterization of deposited material is discussed in terms of microstructure and resistivity. Overall, He-IBID resembles more electron-beam-induced-deposition (EBID) than Ga-ion-beam-induced-deposition (Ga-IBID).
* EBID and Ga-IBID
[1] P.F.A. Alkemade and H. Miro, Appl. Phys. A (2014) 117: 1727. doi:10.1007/s00339-014-8763-y
2:00 PM - *TC03.08.02
Modification of High-Transition Temperature Superconductors with Focused Helium Ion Irradiation
Shane Cybart 1
1 , University of California, Riverside, Riverside, California, United States
Show AbstractThe 1987 discovery of high-TC superconductivity in ceramic materials at temperatures around 90K set off a frenzy of research in the development of high-TC electronics, motivated by the prospects of electronics operating in liquid nitrogen at 77K opposed to 4K liquid helium. Unfortunately, researchers soon discovered that these new materials were much more difficult to process than conventional metal superconductors. High-TC materials are very anisotropic and the superconducting properties vary along the different crystallographic directions which complicates manufacturing of the basic building blocks of superconducting electronics: Josephson junctions. Furthermore, the length scale of superconductivity in high-TC ceramics is very short compared to low-TC metals. Despite these challenges many high-TC Josephson junction manufacturing techniques have emerged over the last three decades but none is able to generate large numbers of junctions with predictable characteristics necessary for large scale circuits. Recently, my group has demonstrated a new scalable nanomanufacturing method of high-TC electronics using the finely focused beam from a helium ion microscope, which has the potential to deliver large numbers of high-quality circuits while at the same time reducing their costs by orders of magnitude. The key to this method is that the material is very sensitive to the oxygen ordering in the crystal lattice which can be altered by light ion irradiation. Increasing ion irradiation levels has the effects of increasing resistivity and reducing the superconducting transition temperature. At modest irradiation levels the material becomes insulating and no longer conducts or superconducts. Restricting this converted region to the nanoscale allows for the creation of in-plane tunneling barriers directly in the material with no resists or etching. In this presenation, I will present some of the novel characteristics and applications of this new remarkable technology ranging including biomedical sensors for neural imaging and advanced wide bandwidth electrically small antennas.
2:30 PM - TC03.08.03
Utilizing the Helium Ion Beam Microscope for Implantation Studies
David Frazer 1 , Yun Yang 1 , Mehdi Balooch 1 , Frances Allen 1 , Peter Hosemann 1
1 , University of California, Berkeley, Berkeley, California, United States
Show AbstractFusion as well as fission applications are concerned about the effects of helium on the structural materials. Transmutation reactions do lead to helium buildup in materials and subsequently to bubble formation. The formed bubbles can alter the mechanical properties of the material and further lead to volumetric swelling. In order to study these phenomena Helium ion beam implantation has been used. In the past it was difficult and lengthy to study a variety of different implantation conditions or dose on materials, especially on the same sample. The development of finely focused ion beams, as they are deployed in the ORION nanofab allows to rapidly probe a variety of different implantation conditions or doses. The ORION nanofab enables accurate and quick implantation of a variety of doses on a single sample which coupled with techniques such as atomic force microscopy (AFM) and nanoindentation allow for rapid analysis of the effect of the ion implantation in the material.
In addition, the ability to accurately implant helium into a defined region on the materials allows to study the effects of implantation of helium on specific regions of interest such as interfaces and evaluate their ability to act as sinks for helium which could improve the materials performance. In this work, we implant a variety of materials to different dose (1E16-1E18 ion/cm2) at room temperature with subsequent AFM and nanoindentation to evaluate the swelling and mechanical property change. In addition, focused ion beam transmission electron microscopy (TEM) liftout foils were manufactured of the implanted regions to evaluate the bubble distribution and size.
We also performed implantation into metal/metal (Cu/Nb) interfaces and metal/oxide (Fe/Y2O3) interfaces to evaluate the interfaces ability to accumulate helium. Post implantation TEM analysis were performed to evaluate the bubble size and distribution and evaluate difference across the interface. Lastly, in-situ TEM heat treatments were performed on the interface materials to evaluate the bubble growth at the interface and in the bulk of the two materials.
2:45 PM - TC03.08.04
In Situ Ion-Beam Microscopy Capabilities at the Sandia Ion-Beam Laboratory
Samuel Briggs 1 , Christopher Barr 1 , Patrick Price 1 , Caitlin Taylor 1 , Brittany Muntifering 1 , Daniel Bufford 1 , Khalid Hattar 1
1 , Sandia National Laboratories, Albuquerque, New Mexico, United States
Show AbstractThe Ion Beam Laboratory (IBL) located at Sandia National Laboratories (SNL) is a state-of-the-art user facility that excels in using ion accelerators and electron microscopes to study and modify materials systems for a variety of applications. An assortment of different accelerators is housed at the IBL, including a HVE 6 MV Tandem, a NEC 1 MV Tandem, a NEC 3 MV Pelletron, a Radio Frequency Quadrupole (RFQ) booster, a HVEE Implanter, an A&D 100 kV Nanoimplanter, and a 10 kV Colutron. One of the many unique experimental capabilities of the IBL are the specially modified electron microscopes that allow for direct observations of radiation-solid interactions. This includes the in-situ ion irradiation transmission electron microscope (I3TEM), a JEOL 2100 200kV LaB6 TEM with dynamic TEM (DTEM) capabilities and a multitude of in-situ specimen holders facilitating simultaneous specimen heating, cooling, straining, biasing, etc.; and the newly-installed in-situ ion irradiation scanning electron microscope (I3SEM), a JEOL JSM-IT300HR/LV 30kV FEG SEM with several in-situ mechanical testing stages. Both microscopes are connected to the HVE 6 MV Tandem, allowing for a variety of ion species with energies ranging to tens of keV to 100 MeV to be directed into their respective experimental chambers during live observation. Furthermore, the I3TEM is also connected to the 10 kV Colutron, allowing for limited triple-beam experiments with H2/D2, He, and a heavy ion irradiating species. In-situ study of ion beam/material interactions has multitude of experimental applications, including radiation damage and nuclear materials research, implantation and doping of semiconductor materials, and ion beam modification of surfaces and subsurfaces. Several examples of experimental electron microscopy observations with in-situ ion beam irradiation and implantation performed at the Sandia IBL will be showcased.
This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA-0003525. A portion of this work was supported by the U.S. Department of Energy, Office of Nuclear Energy under DOE Idaho Operations Office Contract DE-AC07-051D14517 as part of a Nuclear Science User Facilities experiment.
TC03.09: Ion Microscopy Imaging and Resolution
Session Chairs
Wednesday PM, November 29, 2017
Hynes, Level 2, Room 201
3:30 PM - *TC03.09.01
Secondary Electron Hyperspectral Imaging—High Resolution Chemical Characterization by Helium Ions
Cornelia Rodenburg 1 , Robert Masters 1 , Kerry Abrams 1 , Nicola Stehling 1 , Jan Schäfer 4 , Katja Fricke 4 , Robert O'Connell 2 , Yangbo Zhou 2 3 , Hongzhou Zhang 2
1 , University of Sheffield, Sheffield United Kingdom, 4 , Leibniz Institute for Plasma Science and Technology, Greifswald Germany, 2 , Trinity College Dublin, Dublin Ireland, 3 , Nanchang University, Nanchang China
Show AbstractIn the Helium ion microscope, a finely focused probe of Helium Ions can be scanned across a sample surface, thus combining many of the advantages] of focused ion beam (FIB) nano-fabrication [1] and of low voltage scanning electrons microscopy, LV-SEM when the Helium Ion induced secondary electron signal is exploited for imaging.
For LV-SEM secondary electron imaging we have shown that strong chemical contrast and increased spatial resolution can be achieved by exploiting the secondary electron spectrum [2] to carry out hyperspectral imaging [3]. Here, we will present some of the information that only becomes accessible through the analysis of the secondary electron spectrum. We will be presenting secondary electron spectra of a number of materials, including single & multilayer graphene, aerographite, highly oriented pyrolithic graphite, semiconducting polymers and organic/inorganic hybride materials and identify the origin of specific spectra features in these materials. We then present examples of hyperspectral imaging (forming images from secondary electrons of different energies) in order to map nano-scale chemical variations in chemical composition and molecular/order and orientation in these materials on the nano-scale.
Next we show on the example of highly oriented pyrolitic graphite and a number of semiconducting polymers the close relation ship of secondary electron spectra measured in LV-SEM and the Helium ion microscope, and that the secondary electron spectra in the latter can reveal the presence, of both contamination or ion beam damage, which is important in the context of nano-fabrication.
Finally, we demonstrate how the helium ion beam in the Helium Ion Microscope can be successfully used to prepare x-sections of polymer-fullerene films so that nano-scale chemical variations across the film thickness can be mapped.
In summary we present a new route to exploring chemical variations carbon in based materials, in both two and three dimensions, by using helium ion beams in combination with secondary electron hyperspectral imaging.
[1] Gregor Hlawacek et al., “Helium ion microscopy” J. Vac. Sci. Technol. B 32(2), (2014): 020801
[2] Robert C Masters et al. “Sub-nanometre resolution imaging of polymer–fullerene photovoltaic blends using energy-filtered scanning electronmicroscopy” Nature Communications 6 (2015): 6928.
[3] Vikas Kumar et al. "Nanoscale Mapping of Bromide Segregation on the Cross Sections of Complex Hybrid Perovskite Photovoltaic Films Using Secondary Electron Hyperspectral Imaging in a Scanning Electron Microscope." ACS Omega 2 (5) (2017): 2126-2133.
4:00 PM - TC03.09.02
Contrast Differences Between Nitrogen and Helium Ion Induced Secondary Electron Images beyond Instrument Effects
Marek Schmidt 1 , Shinichi Ogawa 2 , Hiroshi Mizuta 1
1 , Japan Advanced Institute of Science and Technology, Nomi Japan, 2 , National Institute of Advanced Industrial Science and Technology, Tsukuba Japan
Show AbstractThe first decade after the commercial integration of a gas field ion source (GFIS) operating with light ions into a microscope has renewed the interest in the focused ion beam technology as the resolution is pushed into the sub-10-nm regime. Helium ions allow for unprecedented depth of view in the secondary electron (SE) imaging mode, and different contrast mechanisms from scanning electron microscopy give additional information about the imaged sample.
The GFIS is capable to generate tightly focused ion beams from other source gases as well, including hydrogen [1], neon [2] and nitrogen [3]. Regarding machining properties, the former ends up as implanted protons in the sample, which in turn avoids swelling that is affecting other gases. Neon and nitrogen, on the other hand, are significantly heavier and are a compromise between gallium ions with larger sputter yield and low resolution, and the hydrogen/helium beams with high resolution but low sputter yield. Nevertheless, nitrogen stands out among all the discussed ion species as it forms very strong covalent bonds. A recent study showed that the covalent bond is not broken during ionization, but instead upon sample impact [4]. The SE contrast was found to be affected by the imaging gas (helium or nitrogen), an effect especially prevalent in samples subjected to considerable oxygen reactive ion etching [5]. However, helium and nitrogen SE images were acquired in the same nanofabrication system, thus effects of the instrument on image formation are possible.
In our talk we will compare images acquired by helium in the Zeiss Orion Plus with those take by helium and nitrogen in the nanofabrication system. These images confirm that the nitrogen ion induced SE formation by nitrogen ions is especially sensitive to the surface properties of carbon. The better contrast of surface defects is explained by the larger lateral scattering just below the surface that increases the mutual illumination.
Acknowledgements: T. Iijima is acknowledged for the usage of the HIM at AIST SCR Station. This research was supported through the Grant-in-Aid for Scientific Research (S) No. 25220904 from Japan Society for the Promotion of Science and the Center Of Innovation (COI) program of the Japan Science Technology Agency.
References:
[1] S. Matsubara et al., Microsc. Microanal., vol. 22, no. S3, pp. 614–615, Jul. 2016.
[2] R. H. Livengood et al., Nucl. Instrum. Methods Phys. Res. Sect. Accel. Spectrometers Detect. Assoc. Equip., vol. 645, no. 1, pp. 136–140, Jul. 2011.
[3] F. Aramaki et al., in Proc. SPIE 9235, Monterey, USA, 2014, vol. 9235, p. 92350F–92350F–8.
[4] M. E. Schmidt et al., “Interaction study of nitrogen ion beam with silicon,” J. Vac. Sci. Technol. B, 2017.
[5] M. E. Schmidt et al., Microsc. Microanal., pp. 1–11, May 2017.
4:15 PM - TC03.09.03
Simulation Based Investigation of Gas Assisted Focused Ion Beam Etching— Elucidating Resolution Effects
Kyle Mahady 1 , Philip Rack 1 2 , Shida Tan 3 , Yuval Greenzweig 4 , Richard Livengood 3 , Amir Raveh 4
1 , University of Tennessee, Knoxville, Tennessee, United States, 2 Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States, 3 , Intel Corporation, Santa Clara, California, United States, 4 , Intel Israel, Haifa Israel
Show AbstractWe present a Monte Carlo simulation study of focused ion beam etching using a gas assist. The use of a precursor gas greatly enhances material removal rate when compared to ion beam sputtering, enabling features such as valleys to be etched with lower ion doses, and consequently less damage to the substrate. However, the geometry of etched features is influenced by ion species, energy, current, and gas pressure, necessitating the use of simulations to fully understand how the nanostructure develops. In this talk, we describe simulations using our simulation code EnvizION, which simulates monolayer adsorption of XeF2 to a SiO2 substrate, and the reactions between adsorbed gas and surface atoms which lead to volatilization and material removal. We study the effect of etching parameters on the shape of etched valleys, and the influence of ion species such as Ne+ and Ga+, to characterize the underlying limitations on etching resolution. Simulations are compared against experimental results, for validation and to understand experimentally observed features.
4:30 PM - TC03.09.04
Investigation of Gas-Assisted Etching, Deposition and Substrate Damage by Primary Ions, within the Single Beam Width of FIB Systems with Ga LMI and Xe ICP Sources
Valery Ray 1 2 , Ali Hadjikhani 1 , Sina Shahbazmohamadi 1
1 Reverse Engineering, Fabrication, Inspection, and Nondestructive Evaluation Center, University of Connecticut, Storrs, Connecticut, United States, 2 , PBS&T, MEO Engineering Company Inc, Methuen, Massachusetts, United States
Show AbstractFocused Ion Beam instruments based on Ga LMIS and Xe ICP sources widely used as material analysis sample preparation tools and in semiconductor failure analysis, while Ga FIB instruments also found use in industrial applications of photolithographic mask repair and semiconductor circuit edit. Shrinkage of features within semiconductor devices under Moore Law created peculiar situation where dimensions of the objects being modified by FIB during circuit edit operations have approached diameter of the ion beam.
We will present results of TEM study of single beam-width sputtering and deposition experiments with Ga and Xe FIB, and the methodology of analyzing gas-assisted processes within single beam width. Results of such analysis help with identifying limitations of each of the primary ion species, demonstrate possibility of using existing FIB technology for editing future generations of semiconductor devices, and indicate directions for future research of interactions of the focused ion beam with materials and directions for development of gas-assisted etching and deposition processes.
References:
[1] Y. Greenzweig et al., “Current Density Profile Characterization and Analysis Method for Focused Ion Beam” Microelectronics Engineering 155 (2016) pp. 19 – 24.
[2] E. Chang et. al., “Reconstructing Focused Ion Beam Current Density Profile by Iterative Simulation Methodology” JVST B 34(6) , 06KO01 (2016)
[3] V. Ray et. al., “Optimizing Gas-Assisted Processes for Ga and Xe FIB Circuit Edit Application” Proc. 42nd ISTFA 2016, pp. 535 – 537
Symposium Organizers
Alex Belianinov, Oak Ridge National Laboratory
Frances Allen, University of California, Berkeley
Shinichi Ogawa, National Institute of Advanced Industrial Science and Technology
Tom Wirtz, Luxembourg Institute of Science and Technology (LIST)
Symposium Support
Raith America, Inc.
ZEISS Microscopy
TC03.10: Novel Ion Sources
Session Chairs
Frances Allen
Alex Belianinov
Thursday AM, November 30, 2017
Hynes, Level 2, Room 201
9:15 AM - *TC03.10.01
Cold-Atom Focused Ion Beams—New Species, Low Energies and High Brightness
Jabez McClelland 1 , William McGehee 1 , Jamie Gardner 1 2 , Evgheni Strelcov 1 2 , Vladimir Oleshko 1 , Saya Takeuchi 3 1 , Thomas Michels 1 4 , Vladimir Aksyuk 1 , Christopher Soles 1 , Andrew Schwarzkopf 5 , Brenton Knuffman 5 , Adam Steele 5
1 , National Institute of Standards and Technology, Gaithersburg, Maryland, United States, 2 Maryland Nanocenter, University of Maryland, College Park, Maryland, United States, 3 , Theiss Research, La Jolla, California, United States, 4 , Ilmenau University of Technology, Ilmenau Germany, 5 , zeroK NanoTech, Gaithersburg, Maryland, United States
Show AbstractWhile most ion sources for focused ion beam (FIB) applications rely on a very sharp tip to create high brightness, a new type of source has recently emerged which instead exploits the extremely cold temperatures attainable through laser cooling [1]. In these sources, the brightness arises not from localizing ion emission to a nanometer-scale area on the surface of a tip, but rather through a dramatic reduction in the random transverse motion of the ions. Here, neutral atoms are cooled to temperatures in the microkelvin range, ionized via near-threshold photoionization, and extracted to form a highly collimated ion beam. The cooling process, which does not involve any cryogens, is based on scattering of near-resonant laser light tuned just below a sharp absorption resonance in the neutral atom, and can attain temperatures as low as 10 μK in some species.
Particular advantages of a cold-atom ion source include access to new ionic species (laser cooling in over 27 atomic species has been demonstrated), a very low energy spread (permitting high resolution focusing at low beam energies), and a brightness that can be significantly higher than the industry standard Ga liquid metal ion source (LMIS). Additional advantages include long term stability, insensitivity to contamination, and controllable emission current from several nanoamperes down to the single ion level.
In our initial demonstration, we created a lithium FIB with energy between 0.5 keV and 4 keV, current of several picoamperes, and focal spot as small as 27 nm [2]. This instrument has proven useful for several diverse new applications, including imaging of photonic modes in microdisk optical resonators [3] and nanoscale injection of Li ions in battery materials to study ion mobility on a local scale [4]. Recently, an improved cold atom source using Cs ions has attained a spot size of 2 nm in a 2 pA beam at 10 keV beam energy. The brightness was measured to be 2.4 x 107 A m-2 sr-1 eV-1, a value 24 times greater than the LMIS [5]. Due to this extremely high brightness and the heavy mass of Cs ions, this source has great promise for applications in areas such as next-generation circuit edit and secondary ion mass spectrometry. These two demonstrations suggest that cold-atom ion sources have great potential for creating a broad diversity of focused ion beams with expanded capabilities.
[1] J.J. McClelland, A.V. Steele, B. Knuffman, K.A. Twedt, A. Schwarzkopf, and T.M. Wilson, Appl. Phys. Rev. 3, 011302 (2016).
[2] B. Knuffman, A.V. Steele, J. Orloff, and J.J. McClelland, New J. Phys. 13, 103035 (2011).
[3] K.A. Twedt, J. Zou, M. Davanco, K. Srinivasan, J.J. McClelland and V.A. Aksyuk, Nature Photonics 10, 35 (2015).
[4] S. Takeuchi, W.R. McGehee, J.L. Schaefer, T.M. Wilson, K.A. Twedt, E.H. Chang, C.L. Soles, V.P Oleshko and J.J. McClelland, J. Electrochem. Soc. 163, A1010 (2016).
[5] A.V. Steele, A. Schwarzkopf, J.J. McClelland, and B. Knuffman, Nano Futures 1, 015005 (2017).
9:45 AM - TC03.10.02
FIB with Ion Species for Advanced Nanofabrication and Ion Implantation—Achievements and Challenges of the Ion Source
Sven Bauerdick 1 , Lothar Bischoff 2 , Lars Bruchhaus 1 , Paul Mazarov 1 , Ralf Jede 1
1 , Raith GmbH, Dortmund Germany, 2 , HZDR, Dresden Germany
Show AbstractToday’s Focused Ion Beam (FIB) tools are mainly based on Gallium liquid metal ion sources (LMIS). We have extended the ion column and source technology towards new ion species employing a liquid metal alloy ion source (LMAIS) and an ExB filter for the long-term stable delivery of multiple ion species. This range of ion species with different mass or charge (Figure 1) can be beneficial for various nanofabrication applications and especially for ion implantation down to the single ion level. We focus mainly on the family of alloys based on Au, Si and Ge, whereas nearly half of the elements of the Periodic Table are in principle available in LMAIS technology (Figure 2).
We present the capabilities of the multiple-species FIB nanofabrication instrument including excellent long-term current stability and sub-20 nm beam resolution with various ions and clusters. We discuss fully characterized ion sources as well as potential candidates for new ion species. In particular applications in quantum photonics and single ion implantation require species like Si, Ge, P, Sb, Bi or Cr. Besides providing the ion beam, a main challenge is the control of the accurate position and ultra-low dose on the sample without any artefacts, as required for creating active vacancy centers [2].
Moreover we will discuss the main properties of a modern LMAIS like long life-time, high brightness and stable ion current. The physical basics and experimental results of LMAIS, their physical properties (I-V characteristics, energy spread) and questions of the preparation technology using elementary as well as binary and ternary alloys as source material will be covered. Furthermore selected applications will be presented to underline the impact of these sources in modern nanotechnology by highly focused ion beams.
TC03.11: Impacts of Novel Ion Source Technology
Session Chairs
Frances Allen
Alex Belianinov
Thursday PM, November 30, 2017
Hynes, Level 2, Room 201
10:30 AM - *TC03.11.01
Mask Repair Technology Using Gas Field Ion Source
Anto Yasaka 1 , Fumio Aramaki 1 , Tomokazu Kozakai 1 , Osamu Matsuda 1 , Kensuke Shiina 1 , Koji Nagahara 1
1 , Hitachi High-Tech Science Center, Tokyo Japan
Show AbstractWe developed a new ion beam based mask repair system using a gas field ion source (GFIS). For conventional photomasks, nitrogen ions were used to repair defects, while hydrogen ions were used for EUVL masks. We evaluated the performance of the mask repair system on MoSi based phase shift masks and EUV masks. The results demonstrate that GFIS technology is a reliable solution of repairing defects on high end photomasks for 1Xnm generation and beyond.
11:00 AM - TC03.11.02
Coldfib—The New FIB Source from Laser Cooled Atoms
Matthieu Viteau 1 , Arnaud Houel 1 , Anne Delobbe 1 , Morgan Reveillard 1 , Daniel Comparat 2
1 , Orsay Physics, Fuveau France, 2 91, Centre National de la Recherche Scientifique (CNRS), Orsay France
Show AbstractCharged particle beams of controlled energy and strong focusing are widely used tools in industry and science. Focused Ion Beam (FIB) column combine with a Scanning Electron Microscope (SEM) provide full control of nanofabrication or nanolithography processes. Ion energy can be varied typically in the 1–30KeV range, with an energy-dependent resolution attaining the nanometer range. State-of-the-art FIBs commercially available are based mainly on plasma, liquid metal tip or helium ion sources for large, intermediate, and low currents, respectively. Despite the very high technological level of the available machines, research of new ion sources allowing even higher resolution and a wider choice of atomic or molecular ions for new and demanding application is very active.
As an example, the world of electronic components evolves regularly towards the miniaturization by integrating a number of transistors more and more important. The dimensions being smaller and smaller (technology 10 nm, 7 nm even 5 nm), nowadays the instruments of analysis used, like the conventional FIB, reach their limit. Thus it’s necessary to realize a technological breakthrough to be able to observe, analyze and modify components and structures on the scale of the nanometer.
Our new system, Coldfib, wants to take up this challenge of the nanomanufacturing by the coupling of two high technologies: the laser cooling of atoms, and manipulation of charged particles.
Very innovative, this industrial solution, based on a source of ions obtained from atoms laser cooled and ionized, will allow realizing ions beam in the unequalled performances, to reach engraving’s sizes of some nanometers. This new technology offers a resolution, for example at 5KeV, 10 times better than the LMIS one, and reaches the nanometer at 30keV.
We’ll present in this talk the integration on the SEM-FIB TESCAN instrument. In addition to the experimental1 part and performances2 will also show some first applications.
1L. Kime, et al., High-flux monochromatic ion and electron beams based on laser-cooled atoms, Phys. Rev. A 88, 033424 (2013)
2M. Viteau, et al., Ion microscopy based on laser-cooled cesium atoms, Ultramicroscopy (2016)
11:15 AM - TC03.11.03
Novel Atomic Layer Etching Using Gas Cluster Ion Beam Irradiation
Noriaki Toyoda 1
1 , University of Hyogo, Himeji Japan
Show AbstractNovel atomic layer etching (ALE) using gas cluster ion beam (GCIB) irradiation was investigated. Since the kinetic energy of gas cluster ions is shared by thousands of gas atoms or molecules, energy/atoms or energy/molecules can be easily reduced to several eV. Therefore, low-damage surface modification is promoted. In additions, since gas cluster ions realize dense energy deposition, chemical reactions on surface are enhanced at low substrate temperature. These characteristics of GCIB are beneficial for ALE process. In general, ALE is promoted by self-limiting steps of adsorption of reactive gas, evacuation of residual gas, and removal of altered layer by ion bombardments. In this study, GCIB is used as a novel low-energy ion beam for removal of altered surface layer. As a feasibility study, ALE of Cu films with oxygen GCIB in acetic acid vapor were investigated. In the beginning of ALE cycle, acetic acid adsorbed on Cu surface. Thin layer of acetic acid remained on Cu after evacuation of residual gas. Subsequently, chemically altered layer was etched by oxygen GCIB irradiation. In the case of 20 keV oxygen GCIB irradiations, Cu atoms with adsorbed acetic acid were removed reactively. However, Cu atoms beneath the surface layer were physically sputtered at the same time. Consequently, the etching process with 20 kV oxygen GCIB was not self-limiting. On the contrary, Cu atoms with adsorbed acetic acid were reactively etched by 5 keV oxygen GCIB, however, Cu atoms beneath layer were not physically sputtered. Therefore, the ALE process with 5 kV oxygen GCIB was self-limiting, which is crucial for ALE. Since there are various combination between adsorbed molecules and target materials, it is expected that ALE with GCIB will be applicable for various materials, such as 2D materials and so on.
11:30 AM - *TC03.11.04
Improving the Study of Bone Diseases by Correlative Electron-, Ion- and X-Ray Microscopy including their Spectroscopic Techniques
Silke Christiansen 1 2 3
1 Christiansen Research Group, Helmholtz Zentrum Berlin für Materialien und Energie, Berlin Germany, 2 Physics Department, Free University, Berlin Germany, 3 Christiansen Research Group, Max Planck Institute for the Science of Light, Erlangen Germany
Show AbstractIn the last decades a lot of knowledge was gathered on the structure and composition of a fascinating bio-material - bone. Bones are a conglomerate of an interconnected network of bone cells, nutrition- and blood channels, embedded in a functional network of nanostructures forming the trabecular and cortical bone.
Cutting-edge correlative high-resolution microscopy and spectroscopy enables to reach the next level of understanding of healthy and diseased bone tissue. Correlative workflows starting from X-ray volume analysis with voxel sizes of ~700nm, over large scale scanning electron microscopy data acquisition, to dual beam microscope analysis (focused electron- and ion beam) allow for investigation of structures at multiple lengths scale and thus merging the “larger picture” and the underlying ultrastructure with statistical significance. In combination with further analytical add-ons, physical properties such as optical, structural, mechanical, compositional, topographical etc. deliver a highly detailed correlative data-set.
In aging and diseased bone tissue, the structure of cortical bone changes at the nano- and ultrastructural level. Correlative microscopy investigations revealed e.g. that in diseased bone many lacunae fill with a-cellular, mineral material. Cellular communication is severely hindered as much as a loss of bone homeostasis takes place and consequently an increase in bone fragility occurs. Calcified nano-pearls (~650 nm in diameter) form and aggregate until ultimately, the lacunae are entirely filled. The a-cellular filling material of lacunae differs in composition compared to the surrounding bone matrix.
The pearls’ composition is studied with nano-scale precision using time-of-flight mass spectrometry (TOFMS) in a dual beam focused electron- and ion-beam (FIBSEM) microscope, using the ion beam to sputter the volume material of interest. In addition, Raman spectroscopy of mineralized pearls provide structural information through the analysis of vibrational modes.
Bone degradation through localized mineralization needs to be further understood to ultimately control and counteract bone’s mechanical degradation by suitable medication and to further strengthen fracture resistance. To understand the underlying metabolic processes of mineralization, further knowledge of the nano-pearls’ composition, morphology and structure are required and combined TOFMS in a FIBSEM correlated with Raman spectroscopy will contribute unique information.
References
P. Milovanovic, E. Zimmermann, B. Hoffmann, G. Sarau, T. Yorgan, M. Amling, S.H. Christiansen, B. Busse, The Formation of Calcified Nanospherites during Micropetrosis Represents a Unique Mineralization Mechanism in Aged Human Bone, small 13(3), 1602215 (2017)