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Ahmed A, Kottke PA, Fedorov AG. Electrochemical Lensing for High Resolution Nanostructure Synthesis in Liquids. ACS APPLIED NANO MATERIALS 2024; 7:15438-15445. [PMID: 39022451 PMCID: PMC11249771 DOI: 10.1021/acsanm.4c02295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Revised: 06/12/2024] [Accepted: 06/13/2024] [Indexed: 07/20/2024]
Abstract
The advancement of liquid phase electron/ion beam induced deposition has enabled an effective direct-write approach for functional nanostructure synthesis with the possibility of three-dimensional control of morphology. For formation of a metallic solid phase, the process employs ambient temperature, beam-guided, electrochemical reduction of precursor cations, resulting in rapid formation of structures, but with challenges for retention of resolution achievable via slower electron beam approaches. The possibility of spatial control of redox pathways via the use of water-ammonia solvents has opened avenues for improved nanostructure resolution without sacrificing the growth rate. In particular, ammonia enables "electrochemical lensing" in which a tightly confined and highly reducing environment is created locally to enable high resolution, rapid beam-directed nanostructure growth. We demonstrate this unique approach to high resolution synthesis through a combination of analysis and experiment.
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Affiliation(s)
- Auwais Ahmed
- George
W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Peter A. Kottke
- George
W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Andrei G. Fedorov
- George
W. Woodruff School of Mechanical Engineering and Parker H. Petit Institute
for Bioengineering and Biosciences, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
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2
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Nydegger M, Wang ZJ, Willinger MG, Spolenak R, Reiser A. Direct In- and Out-of-Plane Writing of Metals on Insulators by Electron-Beam-Enabled, Confined Electrodeposition with Submicrometer Feature Size. SMALL METHODS 2024; 8:e2301247. [PMID: 38183406 DOI: 10.1002/smtd.202301247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/18/2023] [Indexed: 01/08/2024]
Abstract
Additive microfabrication processes based on localized electroplating enable the one-step deposition of micro-scale metal structures with outstanding performance, e.g., high electrical conductivity and mechanical strength. They are therefore evaluated as an exciting and enabling addition to the existing repertoire of microfabrication technologies. Yet, electrochemical processes are generally restricted to conductive or semiconductive substrates, precluding their application in the manufacturing of functional electric devices where direct deposition onto insulators is often required. Here, the direct, localized electrodeposition of copper on a variety of insulating substrates, namely Al2O3, glass and flexible polyethylene, is demonstrated, enabled by electron-beam-induced reduction in a highly confined liquid electrolyte reservoir. The nanometer-size of the electrolyte reservoir, fed by electrohydrodynamic ejection, enables a minimal feature size on the order of 200 nm. The fact that the transient reservoir is established and stabilized by electrohydrodynamic ejection rather than specialized liquid cells can offer greater flexibility toward deposition on arbitrary substrate geometries and materials. Installed in a low-vacuum scanning electron microscope, the setup further allows for operando, nanoscale observation and analysis of the manufacturing process.
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Affiliation(s)
- Mirco Nydegger
- Laboratory for Nanometallurgy, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, Zürich, 8093, Switzerland
| | - Zhu-Jun Wang
- Scientific Center of Optical and Electron Microscopy, ScopeM, ETH Zürich, Otto-Stern Weg 3, Zürich, 8093, Switzerland
- School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai, 201210, People's Republic of China
| | - Marc Georg Willinger
- Scientific Center of Optical and Electron Microscopy, ScopeM, ETH Zürich, Otto-Stern Weg 3, Zürich, 8093, Switzerland
- School of Natural Science, Department of Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85747, Garching, Germany
| | - Ralph Spolenak
- Laboratory for Nanometallurgy, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, Zürich, 8093, Switzerland
| | - Alain Reiser
- Laboratory for Nanometallurgy, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, Zürich, 8093, Switzerland
- Department of Materials Science and Engineering, KTH Royal Institute of Technology, Brinellvägen 23, Stockholm, 11428, Sweden
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3
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Esfandiarpour S, Hastings JT. Limiting regimes for electron-beam induced deposition of copper from aqueous solutions containing surfactants. NANOTECHNOLOGY 2021; 32:155302. [PMID: 33406512 DOI: 10.1088/1361-6528/abd8f5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Focused electron beam induced deposition of pure materials from aqueous solutions has been of interest in recent years. However, controlling the liquid film in partial vacuum is challenging. Here we modify the substrate to increase control over the liquid layer in order to conduct a parametric study of copper deposition in an environmental scanning electron microscope. We identified the transition from electron to mass-transport limited deposition as well as two additional regimes characterized by aggregated and high-aspect ratio deposits. We observe a high deposition efficiency of 1-10 copper atoms per primary electron that is consistent with a radiation chemical model of the deposition process.
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Affiliation(s)
- Samaneh Esfandiarpour
- Electrical and Computer Engineering, University of Kentucky, Lexington, KY 40506, United States of America
| | - J Todd Hastings
- Electrical and Computer Engineering, University of Kentucky, Lexington, KY 40506, United States of America
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4
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Lami SK, Kaphle AP, Briot NJ, Botman A, Todd Hastings J. Nanoscale focused electron beam induced etching of nickel using a liquid reactant. NANOTECHNOLOGY 2020; 31:425301. [PMID: 32580183 DOI: 10.1088/1361-6528/ab9fb4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Nickel nanostructures have found widespread application as both functional components, e.g. in magnetic systems, and as part of the lithographic pattern transfer process as etch masks, EUV mask absorbers, and imprint templates. Electron-beam induced etching of nickel is highly desirable for the repair and editing of masks and templates with high resolution and without substrate damage. However, there are no known gas-phase reactants that produce volatile nickel products under e-beam irradiation. Here we report the successful local etching of nickel by a focused electron beam in an environmental scanning electron microscope using a liquid reactant, aqueous sulfuric acid. Sulfuric acid did not spontaneously etch nickel under ESEM conditions, but nickel was etched in areas exposed to the electron beam. Etching parameters such as dose, refresh time, and addition of a surfactant were investigated. The extent of the etch increases with dose before terminating at sub-micron feature sizes. The etch resolution improves with the addition of surfactant. This approach enables local nickel patterning with complete film removal but without damaging underlying layers. With further refinement, the process may enable nickel absorber repair and editing and remove a significant obstacle to the use of nickel in EUV lithography.
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Affiliation(s)
- Sarah K Lami
- Department of Electrical and Computer Engineering, University of Kentucky, Lexington, Kentucky 40506, United States of America. AL-Furat AL-Awsat Technical University, Najaf 54003, Iraq
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5
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Lami SK, Smith G, Cao E, Hastings JT. The radiation chemistry of focused electron-beam induced etching of copper in liquids. NANOSCALE 2019; 11:11550-11561. [PMID: 31168552 DOI: 10.1039/c9nr01857c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Well-controlled, focused electron-beam induced etching of copper thin films has been successfully conducted on bulk substrates in an environmental scanning electron microscope by controlling liquid-film thickness with an in situ correlative interferometry system. Knowledge of the liquid-film thickness enables a hybrid Monte Carlo/continuum model of the radiation chemistry to accurately predict the copper etch rate using only electron scattering cross-sections, radical yields, and reaction rates from previous studies. Etch rates depended strongly on the thickness of the liquid film and simulations confirmed that this was a result of increased oxidizing radical generation. Etch rates also depended strongly, but non-linearly, on electron beam current, and simulations showed that this effect arises through the dose-rate dependence of reactions of radical species.
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Affiliation(s)
- Sarah K Lami
- Department of Electrical and Computer Engineering, University of Kentucky, Lexington, Kentucky 40506, USA.
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6
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Prabu V, Obst M, Hosseinkhannazer H, Reynolds M, Rosendahl S, Wang J, Hitchcock AP. Instrumentation for in situ flow electrochemical Scanning Transmission X-ray Microscopy (STXM). THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:063702. [PMID: 29960523 DOI: 10.1063/1.5023288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We report the design and performance of a 3-electrode device for real time in situ scanning transmission X-ray microscopy studies of electrochemical processes under both static (sealed, non-flow) conditions and with a continuous flow of electrolytes. The device was made using a combination of silicon microfabrication and 3D printing technologies. The performance is illustrated by results of a study of copper deposition and stripping at a gold working electrode. X-ray absorption spectromicroscopy at the Cu 2p edge was used to follow the evolution as a function of potential and time of the spatial distributions of Cu(0) and Cu(i) species electro-deposited from an aqueous solution of copper sulphate. The results are interpreted in terms of competing mechanisms for the reduction of Cu(ii).
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Affiliation(s)
- Vinod Prabu
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S4M1, Canada
| | - Martin Obst
- BayCEER, University of Bayreuth, D-95448 Bayreuth, Germany
| | | | | | - Scott Rosendahl
- Canadian Light Source, 44 Innovation Boulevard, Saskatoon, Saskatchewan S7N 2V3, Canada
| | - Jian Wang
- Canadian Light Source, 44 Innovation Boulevard, Saskatoon, Saskatchewan S7N 2V3, Canada
| | - Adam P Hitchcock
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S4M1, Canada
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7
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Esfandiarpour S, Boehme L, Hastings JT. Focused electron beam induced deposition of copper with high resolution and purity from aqueous solutions. NANOTECHNOLOGY 2017; 28:125301. [PMID: 28220760 DOI: 10.1088/1361-6528/aa5a4a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Electron-beam induced deposition of high-purity copper nanostructures is desirable for nanoscale rapid prototyping, interconnection of chemically synthesized structures, and integrated circuit editing. However, metalorganic, gas-phase precursors for copper introduce high levels of carbon contamination. Here we demonstrate electron beam induced deposition of high-purity copper nanostructures from aqueous solutions of copper sulfate. The addition of sulfuric acid eliminates oxygen contamination from the deposit and produces a deposit with ∼95 at% copper. The addition of sodium dodecyl sulfate (SDS), Triton X-100, or polyethylene glycole (PEG) improves pattern resolution and controls deposit morphology but leads to slightly reduced purity. High resolution nested lines with a 100 nm pitch are obtained from CuSO4-H2SO4-SDS-H2O. Higher aspect ratios (∼1:1) with reduced line edge roughness and unintended deposition are obtained from CuSO4-H2SO4-PEG-H2O. Evidence for radiation-chemical deposition mechanisms was observed, including deposition efficiency as high as 1.4 primary electrons/Cu atom.
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8
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Shanley TW, Bonnie F, Scott J, Toth M. Role of Gas Molecule Complexity in Environmental Electron Microscopy and Photoelectron Yield Spectroscopy. ACS APPLIED MATERIALS & INTERFACES 2016; 8:27305-27310. [PMID: 27649062 DOI: 10.1021/acsami.6b08681] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Environmental scanning electron microscopy (ESEM) and environmental photoelectron yield spectroscopy (EPYS) enable electron imaging and spectroscopy of surfaces and interfaces in low-vacuum gaseous environments. The techniques are both appealing and limited by the range of gases that can be used to amplify electrons emitted from a sample and used to form images/spectra. However, to date only H2O and NH3 gases have been identified as highly favorable electron amplification media. Here we demonstrate that ethanol vapor (CH3CH2OH) is superior to both of these and attribute its performance to its molecular complexity and valence orbital structure. Our findings improve the present understanding of what constitutes a favorable electron amplification gas and will help expand the applicability and usefulness of the ESEM and EPYS techniques.
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Affiliation(s)
- Toby W Shanley
- School of Physics and Advanced Materials, University of Technology Sydney , Ultimo, NSW 2007, Australia
| | - Fadi Bonnie
- School of Physics and Advanced Materials, University of Technology Sydney , Ultimo, NSW 2007, Australia
| | - John Scott
- School of Physics and Advanced Materials, University of Technology Sydney , Ultimo, NSW 2007, Australia
| | - Milos Toth
- School of Physics and Advanced Materials, University of Technology Sydney , Ultimo, NSW 2007, Australia
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9
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Jesse S, Borisevich AY, Fowlkes JD, Lupini AR, Rack PD, Unocic RR, Sumpter BG, Kalinin SV, Belianinov A, Ovchinnikova OS. Directing Matter: Toward Atomic-Scale 3D Nanofabrication. ACS NANO 2016; 10:5600-18. [PMID: 27183171 DOI: 10.1021/acsnano.6b02489] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Enabling memristive, neuromorphic, and quantum-based computing as well as efficient mainstream energy storage and conversion technologies requires the next generation of materials customized at the atomic scale. This requires full control of atomic arrangement and bonding in three dimensions. The last two decades witnessed substantial industrial, academic, and government research efforts directed toward this goal through various lithographies and scanning-probe-based methods. These technologies emphasize 2D surface structures, with some limited 3D capability. Recently, a range of focused electron- and ion-based methods have demonstrated compelling alternative pathways to achieving atomically precise manufacturing of 3D structures in solids, liquids, and at interfaces. Electron and ion microscopies offer a platform that can simultaneously observe dynamic and static structures at the nano- and atomic scales and also induce structural rearrangements and chemical transformation. The addition of predictive modeling or rapid image analytics and feedback enables guiding these in a controlled manner. Here, we review the recent results that used focused electron and ion beams to create free-standing nanoscale 3D structures, radiolysis, and the fabrication potential with liquid precursors, epitaxial crystallization of amorphous oxides with atomic layer precision, as well as visualization and control of individual dopant motion within a 3D crystal lattice. These works lay the foundation for approaches to directing nanoscale level architectures and offer a potential roadmap to full 3D atomic control in materials. In this paper, we lay out the gaps that currently constrain the processing range of these platforms, reflect on indirect requirements, such as the integration of large-scale data analysis with theory, and discuss future prospects of these technologies.
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Affiliation(s)
| | | | - Jason D Fowlkes
- Department of Materials Sciences, University of Tennessee , Knoxville, Tennessee 37996, United States
| | | | - Philip D Rack
- Department of Materials Sciences, University of Tennessee , Knoxville, Tennessee 37996, United States
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10
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Boehme L, Bresin M, Botman A, Ranney J, Hastings JT. Focused electron beam induced etching of copper in sulfuric acid solutions. NANOTECHNOLOGY 2015; 26:495301. [PMID: 26567988 DOI: 10.1088/0957-4484/26/49/495301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We show here that copper can be locally etched by an electron-beam induced reaction in a liquid. Aqueous sulfuric acid (H2SO4) is utilized as the etchant and all experiments are conducted in an environmental scanning electron microscope. The extent of etch increases with liquid thickness and dose, and etch resolution improves with H2SO4 concentration. This approach shows the feasibility of liquid phase etching for material selectivity and has the potential for circuit editing.
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Affiliation(s)
- Lindsay Boehme
- Department of Electrical and Computer Engineering, University of Kentucky, 453 F. Paul Anderson Tower, Lexington, KY 40506, USA
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11
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Fisher JS, Kottke PA, Kim S, Fedorov AG. Rapid Electron Beam Writing of Topologically Complex 3D Nanostructures Using Liquid Phase Precursor. NANO LETTERS 2015; 15:8385-91. [PMID: 26561872 DOI: 10.1021/acs.nanolett.5b04225] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Advancement of focused electron beam-induced deposition (FEBID) as a versatile direct-write additive nanoscale fabrication technique has been inhibited by poor throughput, limited choice of precursors, and restrictions on possible 3D topologies. Here, we demonstrate FEBID using nanoelectrospray liquid precursor injection to grow carbon and pure metal nanostructures via direct decomposition and electrochemical reduction of the relevant precursors, achieving growth rates 10(5) times greater than those observed in standard gas-phase FEBID. Initiating growth at the free surface of a liquid pool enables fabrication of complex 3D carbon nanostructures with strong adhesion to the substrate. Deposition of silver microstructures at similar growth rates is also demonstrated as a promising avenue for future development of the technique.
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Affiliation(s)
- Jeffrey S Fisher
- George W. Woodruff School of Mechanical Engineering and ‡Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Peter A Kottke
- George W. Woodruff School of Mechanical Engineering and ‡Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Songkil Kim
- George W. Woodruff School of Mechanical Engineering and ‡Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Andrei G Fedorov
- George W. Woodruff School of Mechanical Engineering and ‡Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
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12
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Lai SE, Hong YJ, Chen YT, Kang YT, Chang P, Yew TR. Direct-Writing of Cu Nano-Patterns with an Electron Beam. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2015; 21:1639-1643. [PMID: 26381450 DOI: 10.1017/s1431927615015111] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We demonstrate direct electron beam writing of a nano-scale Cu pattern on a surface with a thin aqueous layer of CuSO4 solution. Electron beams are highly maneuverable down to nano-scales. Aqueous solutions facilitate a plentiful metal ion supply for practical industrial applications, which may require continued reliable writing of sophisticated patterns. A thin aqueous layer on a surface helps to confine the writing on the surface. For this demonstration, liquid sample holder (K-kit) for transmission electron microscope (TEM) was employed to form a sealed space in a TEM. The aqueous CuSO4 solution inside the sample holder was allowed to partially dry until a uniform thin layer was left on the surface. The electron beam thus reduced Cu ions in the solution to form the desired patterns. Furthermore, the influence of e-beam exposure time and CuSO4(aq) concentration on the Cu reduction was studied in this work. Two growth stages of Cu were shown in the plot of Cu thickness versus e-beam exposure time. The measured Cu reduction rate was found to be proportional to the CuSO4(aq) concentration.
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Affiliation(s)
- Shih-En Lai
- Department of Materials Science and Engineering,National Tsing-Hua University,Hsinchu 30013,Taiwan,R.O.C
| | - Ying-Jhan Hong
- Department of Materials Science and Engineering,National Tsing-Hua University,Hsinchu 30013,Taiwan,R.O.C
| | - Yu-Ting Chen
- Department of Materials Science and Engineering,National Tsing-Hua University,Hsinchu 30013,Taiwan,R.O.C
| | - Yu-Ting Kang
- Department of Materials Science and Engineering,National Tsing-Hua University,Hsinchu 30013,Taiwan,R.O.C
| | - Pin Chang
- Department of Materials Science and Engineering,National Tsing-Hua University,Hsinchu 30013,Taiwan,R.O.C
| | - Tri-Rung Yew
- Department of Materials Science and Engineering,National Tsing-Hua University,Hsinchu 30013,Taiwan,R.O.C
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Bresin M, Botman A, Randolph SJ, Straw M, Hastings JT. Liquid phase electron-beam-induced deposition on bulk substrates using environmental scanning electron microscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2014; 20:376-384. [PMID: 24589298 DOI: 10.1017/s1431927614000117] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The introduction of gases, such as water vapor, into an environmental scanning electron microscope is common practice to assist in the imaging of insulating or biological materials. However, this capability may also be exploited to introduce, or form, liquid phase precursors for electron-beam-induced deposition. In this work, the authors report the deposition of silver (Ag) and copper (Cu) structures using two different cell-less in situ deposition methods--the first involving the in situ hydration of solid precursors and the second involving the insertion of liquid droplets using a capillary style liquid injection system. Critically, the inclusion of surfactants is shown to drastically improve pattern replication without diminishing the purity of the metal deposits. Surfactants are estimated to reduce the droplet contact angle to below ~10°.
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Affiliation(s)
- Matthew Bresin
- 1 Department of Electrical and Computer Engineering, University of Kentucky, 453 F. Paul Anderson Tower, Lexington, KY 40506, USA
| | - Aurelien Botman
- 2 FEI Company, 5350 Dawson Creek Drive, Hillsboro, OR 97214, USA
| | | | - Marcus Straw
- 2 FEI Company, 5350 Dawson Creek Drive, Hillsboro, OR 97214, USA
| | - Jeffrey Todd Hastings
- 1 Department of Electrical and Computer Engineering, University of Kentucky, 453 F. Paul Anderson Tower, Lexington, KY 40506, USA
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