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Matthews MB, Kearns SL, Buse B. Electron Beam-Induced Carbon Erosion and the Impact on Electron Probe Microanalysis. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2018; 24:612-622. [PMID: 30442209 DOI: 10.1017/s1431927618015398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Electron beam-induced carbon contamination is a balance between simultaneous deposition and erosion processes. Net erosion rates for a 25 nA 3 kV beam can reduce a 5 nm C coating by 20% in 60 s. Measurements were made on C-coated Bi substrates, with coating thicknesses of 5-20 nm, over a range of analysis conditions. Erosion showed a step-like increase with increasing electron flux density. Both the erosion rate and its rate of change increase with decreasing accelerating voltage. As the flux density decreases the rate of change increases more rapidly with decreasing voltage. Time-dependent intensity (TDI) measurements can be used to correct for errors, in both coating and substrate quantifications, resulting from carbon erosion. Uncorrected analyses showed increasing errors in coating thickness with decreasing accelerating voltage. Although the erosion rate was found to be independent of coating thickness this produces an increasing absolute error with decreasing starting thickness, ranging from 1.5% for a 20 nm C coating on Bi at 15 kV to 14% for a 5 nm coating at 3 kV. Errors in Bi Mα measurement are <1% at 5 kV or above but increase rapidly below this, both with decreasing voltage and increasing coating thickness to 20% for a 20 nm coated sample at 3 kV.
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Affiliation(s)
| | - Stuart L Kearns
- 2University of Bristol,School of Earth Sciences, Wills Memorial Building, Queens Road, Clifton, BS8 1RJ,UK
| | - Ben Buse
- 2University of Bristol,School of Earth Sciences, Wills Memorial Building, Queens Road, Clifton, BS8 1RJ,UK
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2
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Prewett PD, Hagen CW, Lenk C, Lenk S, Kaestner M, Ivanov T, Ahmad A, Rangelow IW, Shi X, Boden SA, Robinson APG, Yang D, Hari S, Scotuzzi M, Huq E. Charged particle single nanometre manufacturing. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2018; 9:2855-2882. [PMID: 30498657 PMCID: PMC6244241 DOI: 10.3762/bjnano.9.266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 10/16/2018] [Indexed: 06/01/2023]
Abstract
Following a brief historical summary of the way in which electron beam lithography developed out of the scanning electron microscope, three state-of-the-art charged-particle beam nanopatterning technologies are considered. All three have been the subject of a recently completed European Union Project entitled "Single Nanometre Manufacturing: Beyond CMOS". Scanning helium ion beam lithography has the advantages of virtually zero proximity effect, nanoscale patterning capability and high sensitivity in combination with a novel fullerene resist based on the sub-nanometre C60 molecule. The shot noise-limited minimum linewidth achieved to date is 6 nm. The second technology, focused electron induced processing (FEBIP), uses a nozzle-dispensed precursor gas either to etch or to deposit patterns on the nanometre scale without the need for resist. The process has potential for high throughput enhancement using multiple electron beams and a system employing up to 196 beams is under development based on a commercial SEM platform. Among its potential applications is the manufacture of templates for nanoimprint lithography, NIL. This is also a target application for the third and final charged particle technology, viz. field emission electron scanning probe lithography, FE-eSPL. This has been developed out of scanning tunneling microscopy using lower-energy electrons (tens of electronvolts rather than the tens of kiloelectronvolts of the other techniques). It has the considerable advantage of being employed without the need for a vacuum system, in ambient air and is capable of sub-10 nm patterning using either developable resists or a self-developing mode applicable for many polymeric resists, which is preferred. Like FEBIP it is potentially capable of massive parallelization for applications requiring high throughput.
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Affiliation(s)
- Philip D Prewett
- Oxford Scientific Consultants Ltd, 67 High Street, Dorchester-on-Thames, OX10 7HN, UK
| | - Cornelis W Hagen
- Department of Imaging Physics, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, Netherlands
| | - Claudia Lenk
- Department of Micro- and Nanoelectronic Systems, Ilmenau University of Technology, Max-Planck-Ring 1, Ilmenau 98693, Germany
| | - Steve Lenk
- Department of Micro- and Nanoelectronic Systems, Ilmenau University of Technology, Max-Planck-Ring 1, Ilmenau 98693, Germany
| | - Marcus Kaestner
- Department of Micro- and Nanoelectronic Systems, Ilmenau University of Technology, Max-Planck-Ring 1, Ilmenau 98693, Germany
| | - Tzvetan Ivanov
- Department of Micro- and Nanoelectronic Systems, Ilmenau University of Technology, Max-Planck-Ring 1, Ilmenau 98693, Germany
| | - Ahmad Ahmad
- Department of Micro- and Nanoelectronic Systems, Ilmenau University of Technology, Max-Planck-Ring 1, Ilmenau 98693, Germany
| | - Ivo W Rangelow
- Department of Micro- and Nanoelectronic Systems, Ilmenau University of Technology, Max-Planck-Ring 1, Ilmenau 98693, Germany
| | - Xiaoqing Shi
- Electronics and Computer Science, University of Southampton, Southampton, SO17 1BJ, UK
| | - Stuart A Boden
- Electronics and Computer Science, University of Southampton, Southampton, SO17 1BJ, UK
| | - Alex P G Robinson
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Dongxu Yang
- School of Physics and Astronomy, University of Birmingham, Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Sangeetha Hari
- Department of Imaging Physics, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, Netherlands
| | - Marijke Scotuzzi
- Department of Imaging Physics, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, Netherlands
| | - Ejaz Huq
- Oxford Scientific Consultants Ltd, 67 High Street, Dorchester-on-Thames, OX10 7HN, UK
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3
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Neustetter M, Mauracher A, Limão-Vieira P, Denifl S. Complete ligand loss in electron ionization of the weakly bound organometallic tungsten hexacarbonyl dimer. Phys Chem Chem Phys 2016; 18:9893-6. [PMID: 27006205 DOI: 10.1039/c6cp00558f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We observed the bare W2(+) metal cation upon electron ionization of the weakly bound W(CO)6 dimer. This metal cation can be only observed due to the fast conversion of the weak cluster bond into a strong covalent bond between the metal moieties.
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Affiliation(s)
- Michael Neustetter
- Institut für Ionenphysik und Angewandte Physik, Leopold Franzens Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.
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4
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Hayashida M, Malac M, Bergen M, Li P. Nano-dot markers for electron tomography formed by electron beam-induced deposition: Nanoparticle agglomerates application. Ultramicroscopy 2014; 144:50-7. [DOI: 10.1016/j.ultramic.2014.04.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 02/04/2014] [Accepted: 04/18/2014] [Indexed: 10/25/2022]
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5
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Arnold G, Timilsina R, Fowlkes J, Orthacker A, Kothleitner G, Rack PD, Plank H. Fundamental resolution limits during electron-induced direct-write synthesis. ACS APPLIED MATERIALS & INTERFACES 2014; 6:7380-7. [PMID: 24761930 DOI: 10.1021/am5008003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
In this study, we focus on the resolution limits for quasi 2-D single lines synthesized via focused electron-beam-induced direct-write deposition at 5 and 30 keV in a scanning electron microscope. To understand the relevant proximal broadening effects, the substrates were thicker than the beam penetration depth and we used the MeCpPt(IV)Me3 precursor under standard gas injection system conditions. It is shown by experiment and simulation how backscatter electron yields increase during the initial growth stages which broaden the single lines consistent with the backscatter range of the deposited material. By this it is shown that the beam diameter together with the evolving backscatter radius of the deposit material determines the achievable line widths even for ultrathin deposit heights in the sub-5-nm regime.
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Affiliation(s)
- Georg Arnold
- Institute for Electron Microscopy and Nanoanalsis, Graz University of Technology , Steyrergasse 17, 8010 Graz, Austria
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6
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van Dorp WF, Beyer A, Mainka M, Gölzhäuser A, Hansen TW, Wagner JB, Hagen CW, De Hosson JTM. Focused electron beam induced processing and the effect of substrate thickness revisited. NANOTECHNOLOGY 2013; 24:345301. [PMID: 23899908 DOI: 10.1088/0957-4484/24/34/345301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The current understanding in the study of focused electron beam induced processing (FEBIP) is that the growth of a deposit is mainly the result of secondary electrons (SEs). This suggests that the growth rate for FEBIP is affected by the SE emission from the support. Our experiments, with membranes thinner than the SE escape depth, confirm this hypothesis. We used membranes of 1.4 and 4.3 nm amorphous carbon as supports. At the very early stage, the growth is support-dominated and the growth rate on a 4.3 nm thick membrane is three times higher than on a 1.4 nm thick membrane. This is consistent with Monte Carlo simulations for SE emission. The results suggest that SEs are dominant in the dissociation of W(CO)6 on thin membranes. The best agreement between simulations and experiment is obtained for SEs with energies between 3 and 6 eV.With this work we revisit earlier experiments, working at a precursor pressure 20 times lower than previously. Then, despite using membranes thinner than the SE escape depth, we did not see an effect on the experimental growth rate. We explain our current results by the fact that very early in the process, the growth becomes dominated by the growing deposit itself.
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Affiliation(s)
- W F van Dorp
- Materials Science, Zernike Institute for Advanced Materials, University of Groningen, Nijenborg 4, 9747 AG Groningen, The Netherlands.
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7
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Rosenberg SG, Barclay M, Fairbrother DH. Electron induced reactions of surface adsorbed tungsten hexacarbonyl (W(CO)6). Phys Chem Chem Phys 2013; 15:4002-15. [PMID: 23400276 DOI: 10.1039/c3cp43902j] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Tungsten hexacarbonyl (W(CO)(6)) is frequently used as an organometallic precursor to create metal-containing nanostructures in electron beam induced deposition (EBID). However, the fundamental electron stimulated reactions responsible for both tungsten deposition and the incorporation of carbon and oxygen atom impurities remain unclear. To address this issue we have studied the effect of 500 eV incident electrons on nanometer thick films of W(CO)(6) under Ultra-High Vacuum (UHV) conditions. Results from X-ray Photoelectron Spectroscopy, Mass Spectrometry, and Infrared Spectroscopy reveal that the initial step involves electron stimulated desorption of multiple CO ligands from parent W(CO)(6) molecules and the formation of partially decarbonylated tungsten species (W(x)(CO)(y)). Subsequent electron interactions with these W(x)(CO)(y) species lead to ligand decomposition rather than further CO desorption, ultimately producing oxidized tungsten atoms incorporated in a carbonaceous matrix. The presence of co-adsorbed water during electron irradiation increased the extent of tungsten oxidation. The electron stimulated deposition cross-section of W(CO)(6) at an incident electron energy of 500 eV was calculated to be 6.50 × 10(-16) cm(-2). When considered collectively with findings from previous precursors (MeCpPtMe(3) and Pt(PF(3))(4)), results from the present study are consistent with the idea that the electron induced reactions in EBID are initiated by low energy secondary electrons generated by primary beam-substrate interactions, rather than by the primary beam itself.
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8
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Chee SW, Sharma R. Controlling the size and the activity of Fe particles for synthesis of carbon nanotubes. Micron 2012; 43:1181-7. [DOI: 10.1016/j.micron.2012.01.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Revised: 01/12/2012] [Accepted: 01/21/2012] [Indexed: 11/15/2022]
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9
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Hayashida M, Iijima T, Fujimoto T, Ogawa S. Position-controlled marker formation by helium ion microscope for aligning a TEM tomographic tilt series. Micron 2012; 43:992-5. [PMID: 22542313 DOI: 10.1016/j.micron.2012.03.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 03/15/2012] [Accepted: 03/15/2012] [Indexed: 11/18/2022]
Abstract
We formed nano-dots using a helium ion microscope (HIM) equipped with a gas injection system. Because of position controllability, the nano-dot markers could be placed efficiently on a specimen using the HIM. The sizes of the dots were controlled by changing the beam radiation time. We tried for the first time to form dots on a rod-shaped specimen to use them as markers for aligning a transmission electron microscope tomographic tilt series before reconstructing 3D images.
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Affiliation(s)
- Misa Hayashida
- National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology-AIST, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
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10
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van Dorp WF, Lazić I, Beyer A, Gölzhäuser A, Wagner JB, Hansen TW, Hagen CW. Ultrahigh resolution focused electron beam induced processing: the effect of substrate thickness. NANOTECHNOLOGY 2011; 22:115303. [PMID: 21301081 DOI: 10.1088/0957-4484/22/11/115303] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
It is often suggested that the growth in focused electron beam induced processing (FEBIP) is caused not only by primary electrons, but also (and even predominantly) by secondary electrons (SEs). If that is true, the growth rate for FEBIP can be changed by modifying the SE yield. Results from our Monte Carlo simulations show that the SE yield changes strongly with substrate thickness for thicknesses below the SE escape depth. However, our experimental results show that the growth rate is independent of the substrate thickness. Deposits with an average size of about 3 nm were written on 1 and 9 nm thick carbon substrates. The apparent contradiction between simulation and experiment is explained by simulating the SE emission from a carbon substrate with platinum deposits on the surface. It appears that the SE emission is dominated by the deposits rather than the carbon substrate, even for deposits as small as 0.32 nm(3).
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Affiliation(s)
- W F van Dorp
- Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands.
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11
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Fowlkes JD, Rack PD. Fundamental electron-precursor-solid interactions derived from time-dependent electron-beam-induced deposition simulations and experiments. ACS NANO 2010; 4:1619-29. [PMID: 20201541 DOI: 10.1021/nn901363a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Unknown parameters critical to understanding the electron-precursor-substrate interactions during electron-beam-induced deposition (EBID) have long limited our ability to fully control this nanoscale, directed assembly method. We report here values that describe the precursor-solid interaction, the precursor surface diffusion coefficient (D), the precursor sticking probability (delta), and the mean precursor surface residence time (tau), which are critical parameters for understanding the assembly of EBID deposits. Values of D = 6.4 microm(2) s(-1), delta = 0.0250, and tau = 3.20 ms were determined for a commonly used precursor molecule, tungsten hexacarbonyl W(CO)6. Space and time predictions of the adsorbed precursor coverage were solved by an explicit finite differencing numerical scheme. Evolving nanopillar surface morphology was derived from simulations considering electron-induced dissociation as the critical depletion term. This made it possible to infer the space- and time-dependent precursor coverage both on and around nanopillar structures to better understand local precursor dynamics during mass-transport-limited (MTL) and reaction-rate-limited (RRL) EBID.
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Affiliation(s)
- Jason D Fowlkes
- Nanofabrication Research Laboratory, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37381-6487, USA.
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12
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Dhawan A, Gerhold M, Madison A, Fowlkes J, Russell PE, Vo-Dinh T, Leonard DN. Fabrication of nanodot plasmonic waveguide structures using FIB milling and electron beam-induced deposition. SCANNING 2009; 31:139-146. [PMID: 19670460 DOI: 10.1002/sca.20152] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Fabrication of metallic Au nanopillars and linear arrays of Au-containing nanodots for plasmonic waveguides is reported in this article by two different processes-focused ion beam (FIB) milling of deposited thin films and electron beam-induced deposition (EBID) of metallic nanostructures from an organometallic precursor gas. Finite difference time domain (FDTD) modeling of electromagnetic fields around metallic nanostructures was used to predict the optimal size and spacing between nanostructures useful for plasmonic waveguides. Subsequently, a multi-step FIB fabrication method was developed for production of metallic nanorods and nanopillars of the size and geometry suggested by the results of the FDTD simulations. Nanostructure fabrication was carried out on planar substrates including Au-coated glass, quartz, and mica slides as well as cleaved 4-mode optical fibers. In the second fabrication process, EBID was utilized for the development of similar nanostructures on planar Indium Tin Oxide and Titanium-coated glass substrates. Each method allows formation of nanostructures such that the plasmon resonances associated with the nanostructures could be engineered and precisely controlled by controlling the nanostructure size and shape. Linear arrays of low aspect ratio nanodot structures ranging in diameter between 50-70 nm were fabricated using EBID. Preliminary dark field optical microscopy demonstrates differences in the plasmonic response of the fabricated structures.
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Affiliation(s)
- Anuj Dhawan
- U. S. Army Research Office, Research Triangle Park, Durham, North Carolina, USA.
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13
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van Dorp WF, Hagen CW, Crozier PA, Kruit P. Growth behavior near the ultimate resolution of nanometer-scale focused electron beam-induced deposition. NANOTECHNOLOGY 2008; 19:225305. [PMID: 21825760 DOI: 10.1088/0957-4484/19/22/225305] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
An attempt has been made to reach the ultimate spatial resolution for electron beam-induced deposition (EBID) using W(CO)(6) as a precursor. The smallest dots that have been written have an average diameter of 0.72 nm at full width at half maximum (FWHM). A study of the nucleation stage revealed that the growth is different for each dot, despite identical growth conditions. The center of mass of each dot is not exactly on the position irradiated by the e-beam but on a random spot close to the irradiated spot. Also, the growth rate is not constant during deposition and the final deposited volume varies from dot to dot. The annular dark field signal was recorded during growth in the hope to find discrete steps in the signal which would be evidence of the one-by-one deposition of single molecules. Discrete steps were not observed, but by combining atomic force microscope measurements and a statistical analysis of the deposited volumes, it was possible to estimate the average volume of the units of which the deposits consist. It is concluded that the volume per unit is as small as 0.4 nm(3), less than twice the volume of a single W(CO)(6) molecule in the solid phase.
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Affiliation(s)
- W F van Dorp
- Delft University of Technology, Faculty of Applied Sciences, Lorentzweg 1, 2628 CJ Delft, The Netherlands
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14
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Lukasczyk T, Schirmer M, Steinrück HP, Marbach H. Electron-beam-induced deposition in ultrahigh vacuum: lithographic fabrication of clean iron nanostructures. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2008; 4:841-6. [PMID: 18457333 DOI: 10.1002/smll.200701095] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The generation of nanostructures with arbitrary shapes and well-defined chemical composition is still a challenge and targets the core of the fast-growing field of nanotechnology. One approach is the maskless nanofabrication technique of electron-beam-induced deposition (EBID). Up to now, the purity of these EBID structures has been rather poor. Here we demonstrate that by performing the EBID process solely under ultrahigh vacuum conditions, the lithographic generation of iron nanostructures on Si(100) with an unprecedented purity of higher than 95% is possible. One particular new aspect is the formation of EBID deposits with reduced size in a strain-induced diffusive process, resulting in deposits significantly smaller than 10 nm.
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Affiliation(s)
- Thomas Lukasczyk
- Lehrstuhl für Physikalische Chemie II, Interdisciplinary Center for Molecular Materials, Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany
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15
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Song M, Furuya K. Fabrication and characterization of nanostructures on insulator substrates by electron-beam-induced deposition. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2008; 9:023002. [PMID: 27877950 PMCID: PMC5099707 DOI: 10.1088/1468-6996/9/2/023002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Revised: 08/01/2008] [Accepted: 02/19/2008] [Indexed: 05/22/2023]
Abstract
The fabrication, characterization, and decoration with metallic nanoparticles of nanostructures such as nanowhiskers, nanodendrites, and fractal-like nanotrees on insulator substrates by electron-beam-induced deposition (EBID) are reviewed. Nanostructures with different morphologies of whiskers, dendrites, or trees are fabricated on insulator (Al2O3 or SiO2) substrates by EBID in transmission electron microscopes by controlling the irradiation conditions such as the electron beam intensity. The growth of the nanostructure is related to the accumulation of charges on the surface of a substrate during electron-beam irradiation. A high concentration of the target metallic element and nanocrystal grains of the element are contained in the fabricated nanostructures. The process of growth of the nanostructures is explained qualitatively on the basis of mechanisms in which the formation of the nanostructures is considered to be related to the nanoscaled unevenness of the charge distribution on the surface of the substrate, the movement of the charges to the convex surface of the substrate, and the accumulation of charges at the tip of the grown nanostructure. Novel composite structures of Pt nanoparticle/tungsten (W) nanodendrite or Au nanoparticle/W nanodendrite are fabricated by the decoration of W nanodendrites with metallic elements. Because they have superior features, such as a large specific surface area, a freestanding structure on substrates, a typical size of several nanometers of the tip or the branch, and high purity, the nanostructures may have applications in technologies such as catalysts, sensors, and electron emitters. However, there are still some subjects that should be further studied before their application.
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16
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Lobo CJ, Toth M, Wagner R, Thiel BL, Lysaght M. High resolution radially symmetric nanostructures from simultaneous electron beam induced etching and deposition. NANOTECHNOLOGY 2008; 19:025303. [PMID: 21817540 DOI: 10.1088/0957-4484/19/02/025303] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Electron beam induced etching (EBIE) and deposition (EBID) are promising fabrication techniques in which an electron beam is used to dissociate surface-adsorbed precursor molecules to achieve etching or deposition. Spatial resolution is normally limited by the electron flux distribution at the substrate surface. Here we present simultaneous EBIE and EBID (EBIED) as a method for surpassing this resolution limit by using adsorbate depletion to induce etching and deposition in adjacent regions within the electron flux profile. Our simulation results indicate the possibility of growth control of radially symmetric nanostructures at the sub-1 nm length scale on bulk substrates. The technique is well suited to the fabrication of ring-shaped nanostructures such as those employed in plasmonics, sensing devices, magneto-optics and magnetoelectronics.
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Affiliation(s)
- Charlene J Lobo
- College of Nanoscale Science and Engineering, State University of New York at Albany, 251 Fuller Road, Albany, NY 12203, USA. Microstructural Analysis Unit, University of Technology, Sydney, Broadway, NSW 2007, Australia
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19
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Furuya K. Nanofabrication by advanced electron microscopy using intense and focused beam ∗. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2008; 9:014110. [PMID: 27877936 PMCID: PMC5099805 DOI: 10.1088/1468-6996/9/1/014110] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2008] [Revised: 05/27/2008] [Accepted: 03/13/2008] [Indexed: 05/19/2023]
Abstract
The nanogrowth and nanofabrication of solid substances using an intense and focused electron beam are reviewed in terms of the application of scanning and transmission electron microscopy (SEM, TEM and STEM) to control the size, position and structure of nanomaterials. The first example discussed is the growth of freestanding nanotrees on insulator substrates by TEM. The growth process of the nanotrees was observed in situ and analyzed by high-resolution TEM (HRTEM) and was mainly controlled by the intensity of the electron beam. The second example is position- and size-controlled nanofabrication by STEM using a focused electron beam. The diameters of the nanostructures grown ranged from 4 to 20 nm depending on the size of the electron beam. Magnetic nanostructures were also obtained using an iron-containing precursor gas, Fe(CO)5. The freestanding iron nanoantennas were examined by electron holography. The magnetic field was observed to leak from the nanostructure body which appeared to act as a 'nanomagnet'. The third example described is the effect of a vacuum on the size and growth process of fabricated nanodots containing W in an ultrahigh-vacuum field-emission TEM (UHV-FE-TEM). The size of the dots can be controlled by changing the dose of electrons and the partial pressure of the precursor. The smallest particle size obtained was about 1.5 nm in diameter, which is the smallest size reported using this method. Finally, the importance of a smaller probe and a higher electron-beam current with atomic resolution is emphasized and an attempt to develop an ultrahigh-vacuum spherical aberration corrected STEM (Cs-corrected STEM) at NIMS is reported.
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Affiliation(s)
- Kazuo Furuya
- High Voltage Electron Microscopy Station, National Institute for Materials Science, 3-13 Sakura, Tsukuba 305-0003, Japan
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Toth M, Lobo CJ, Knowles WR, Phillips MR, Postek MT, Vladár AE. Nanostructure fabrication by ultra-high-resolution environmental scanning electron microscopy. NANO LETTERS 2007; 7:525-30. [PMID: 17298020 DOI: 10.1021/nl062848c] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Electron beam induced deposition (EBID) is a maskless nanofabrication technique capable of surpassing the resolution limits of resist-based lithography. However, EBID fabrication of functional nanostructures is limited by beam spread in bulk substrates, substrate charging, and delocalized film growth around deposits. Here, we overcome these problems by using environmental scanning electron microscopy (ESEM) to perform EBID and etching while eliminating charging artifacts at the nanoscale. Nanostructure morphology is tailored by slimming of deposits by ESEM imaging in the presence of a gaseous etch precursor and by pre-etching small features into a deposit (using a stationary or a scanned electron beam) prior to a final imaging process. The utility of this process is demonstrated by slimming of nanowires deposited by EBID, by the fabrication of gaps (between 4 and 7 nm wide) in the wires, and by the removal of thin films surrounding such nanowires. ESEM imaging provides a direct view of the slimming process, yielding process resolution that is limited by ESEM image resolution ( approximately 1 nm) and surface roughening occurring during etching.
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Affiliation(s)
- Milos Toth
- FEI Company, 29 Water Street #216-217, Newburyport, Massachusetts 01950, USA.
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Hagen CW, Silvis-Cividjian N, Kruit P. Resolution limit for electron beam-induced deposition on thick substrates. SCANNING 2006; 28:204-11. [PMID: 16898667 DOI: 10.1002/sca.4950280402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Recently, the fabrication resolution in electron beam-induced deposition (EBID) has improved significantly. Dots with an average diameter of 1 nm have been made. These results were all obtained in transmission electron microscopes on thin samples. As one may think that such resolution can be achieved on thin samples only, it is the objective of this paper to show that this should also be possible on thick samples. For that purpose we use Monte Carlo simulations of the electron-sample interaction and determine the surface area where secondary electrons are emitted. Assuming that these electrons cause the deposition in EBID, a comparison can be made between deposition on a thin and a thick sample. The Monte Carlo code we developed will be described and applied to the deposition induced by a 200 keV primary electron beam on an ultra-thin (10 nm) and a bulk-like (1,000 nm) Cu sample. Near the point of incidence of the primary beam, the deposit size is independent of the substrate thickness, such that a 1-nm resolution should be possible to achieve on a thick substrate as well. Thicker substrates only affect the tails of the deposit distribution which contain more mass than thin substrate deposit tails.
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Affiliation(s)
- C W Hagen
- Delft University of Technology, Faculty of Applied Sciences, Delft, The Netherlands.
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Statistical variation analysis of sub-5-nm-sized electron-beam-induced deposits. ACTA ACUST UNITED AC 2006. [DOI: 10.1116/1.2170099] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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van Dorp WF, van Someren B, Hagen CW, Kruit P, Crozier PA. Approaching the resolution limit of nanometer-scale electron beam-induced deposition. NANO LETTERS 2005; 5:1303-7. [PMID: 16178228 DOI: 10.1021/nl050522i] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We report the writing of very high resolution tungsten containing dots in regular arrays by electron beam-induced deposition (EBID). The size averaged over 100 dots was 1.0 nm at fwhm. Because of the statistical spread in the dot size, large and small dots are present in the arrays, with the smallest having a diameter of only 0.7 nm at fwhm. To date these are the smallest features fabricated by EBID. We have also fabricated lines with the smallest having a width at fwhm of 1.9 nm and a spacing of 3.2 nm.
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Affiliation(s)
- Willem F van Dorp
- Delft University of Technology, Faculty of Applied Sciences, Lorentzweg 1, 2628 CJ Delft, The Netherlands
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