Continuum models of focused electron beam induced processing

• Milos Toth,
• Charlene Lobo,
• Vinzenz Friedli,
• Aleksandra Szkudlarek and
• Ivo Utke

Beilstein J. Nanotechnol. 2015, 6, 1518–1540, doi:10.3762/bjnano.6.157

• deposition (FEBIE and FEBID), and (iii) etch processes that proceed through multiple reaction pathways and generate a number of reaction products at the substrate surface. We also review and release software for Monte Carlo modeling of the precursor gas flux which is needed as an input parameter for

• beam induced etching (FEBIE), deposition (FEBID) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] and surface functionalization [17] techniques. They are typically used to simulate growth rates and nanostructure geometries as a function of experimental parameters, and to help elucidate the

• laws. Numerical models can account for adsorbate diffusion and enable modeling of processes such as simultaneous FEBIE and FEBID performed using a mixture of precursor gases. Here we provide software that can be used to simulate a wide range of processes reported in the FEBIP literature, and review the

Formation of pure Cu nanocrystals upon post-growth annealing of Cu–C material obtained from focused electron beam induced deposition: comparison of different methods

• Aleksandra Szkudlarek,
• Alfredo Rodrigues Vaz,
• Yucheng Zhang,
• Andrzej Rudkowski,
• Czesław Kapusta,
• Rolf Erni,
• Stanislav Moshkalev and
• Ivo Utke

Beilstein J. Nanotechnol. 2015, 6, 1508–1517, doi:10.3762/bjnano.6.156

• study in detail the post-growth annealing of a copper-containing material deposited with focused electron beam induced deposition (FEBID). The organometallic precursor Cu(II)(hfac)2 was used for deposition and the results were compared to that of compared to earlier experiments with (hfac)Cu(I)(VTMS

• electron microscope favored the formation of Cu nanocrystals within the carbonaceous matrix of freestanding rods and suppressed the formation on their surface. Electrical four-point measurements on FEBID lines from Cu(hfac)2 showed five orders of magnitude improvement in conductivity when being annealed

• conventionally and by laser-induced heating in the scanning electron microscope chamber. Keywords: Cu(hfac)2; Cu nanocrystals; focused electron beam induced deposition (FEBID); post-growth annealing of Cu–C material; Introduction Focused electron beam induced deposition (FEBID) is a direct maskless

Influence of the shape and surface oxidation in the magnetization reversal of thin iron nanowires grown by focused electron beam induced deposition

• Luis A. Rodríguez,
• Lorenz Deen,
• Rosa Córdoba,
• César Magén,
• Etienne Snoeck,
• Bert Koopmans and
• José M. De Teresa

Beilstein J. Nanotechnol. 2015, 6, 1319–1331, doi:10.3762/bjnano.6.136

• Aragón (ICMA), Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain 10.3762/bjnano.6.136 Abstract Iron nanostructures grown by focused electron beam induced deposition (FEBID) are promising for applications in magnetic sensing, storage and logic. Such applications require a precise design and

• determination of the coercive field (HC), which depends on the shape of the nanostructure. In the present work, we have used the Fe2(CO)9 precursor to grow iron nanowires by FEBID in the thickness range from 10 to 45 nm and width range from 50 to 500 nm. These nanowires exhibit an Fe content between 80 and 85

• indicate that these wires have a bell-type shape with a surface oxide layer of about 5 nm. Such features are decisive in the actual value of HC as micromagnetic simulations demonstrate. These results will help to make appropriate designs of magnetic nanowires grown by FEBID. Keywords: coercive field

Structural transitions in electron beam deposited Co–carbonyl suspended nanowires at high electrical current densities

• Gian Carlo Gazzadi and
• Stefano Frabboni

Beilstein J. Nanotechnol. 2015, 6, 1298–1305, doi:10.3762/bjnano.6.134

• –carbonyl precursor (Co2(CO)8) by focused electron beam induced deposition (FEBID). The SNWs dimensions are about 30–50 nm in diameter and 600–850 nm in length. The as-deposited material has a nanogranular structure of mixed face-centered cubic (FCC) and hexagonal close-packed (HCP) Co phases, and a

• graphitized C. The breakdown current density is found at 2.1 × 107 A/cm2. The role played by resistive heating and electromigration in these transitions is discussed. Keywords: cobalt; electromigration; focused electron beam induced deposition (FEBID); metallic nanowires; Introduction The growing importance

• deposition (FEBID), a direct-write nanolithography based on the decomposition of gas precursors molecules with electron beams [1]. This technology, in fact, allows for the deposition of various materials on planar and non-planar substrates with nanoscale resolution [2], and it can be easily implemented on

Surface excitations in the modelling of electron transport for electron-beam-induced deposition experiments

• Francesc Salvat-Pujol,
• Roser Valentí and
• Wolfgang S. Werner

Beilstein J. Nanotechnol. 2015, 6, 1260–1267, doi:10.3762/bjnano.6.129

• /bjnano.6.129 Abstract The aim of the present overview article is to raise awareness of an essential aspect that is usually not accounted for in the modelling of electron transport for focused-electron-beam-induced deposition (FEBID) of nanostructures: Surface excitations are on the one hand responsible

• present a general perspective of recent works on the subject of surface excitations and on low-energy electron transport, highlighting the most relevant aspects for the modelling of electron transport in FEBID simulations. Keywords: focused-electron-beam-induced deposition (FEBID); Monte Carlo simulation

• , including a number of spectroscopies (electron-energy-loss spectroscopy, X-ray photoelectron spectroscopy, and Auger-electron spectroscopy), electron microscopy, and the focused-electron-beam-induced deposition (FEBID) of nanostructures, on which we focus here. This technique employs beams of focussed

Tunable magnetism on the lateral mesoscale by post-processing of Co/Pt heterostructures

• Oleksandr V. Dobrovolskiy,
• Maksym Kompaniiets,
• Roland Sachser,
• Fabrizio Porrati,
• Christian Gspan,
• Harald Plank and
• Michael Huth

Beilstein J. Nanotechnol. 2015, 6, 1082–1090, doi:10.3762/bjnano.6.109

• heterostructures on the lateral mesoscale. By means of in situ post-processing of Pt- and Co-based nano-stripes prepared by focused electron beam induced deposition (FEBID) we are able to locally tune their coercive field and remanent magnetization. Whereas single Co-FEBID nano-stripes show no hysteresis, we find

• film techniques or by an alternative approach, as used by us, namely the direct writing of metal-based layers by focused electron beam induced deposition (FEBID) [18][19]. The resolution of FEBID is better than 10 nm laterally and 1 nm vertically [18][19] and, thus, its proven applications range from

• photomask repair [20] to fabrication of nanowires [17][21], nanopores [22], magnetic [5][12] and strain sensors [23] as well as direct-write superconductors [24]. The precursors Co2(CO)8 and (CH3)3CH3PtC5H4 from which Pt- an Co-based structures can be fabricated in the FEBID process, like most metal-organic

Electron-stimulated purification of platinum nanostructures grown via focused electron beam induced deposition

• Brett B. Lewis,
• Michael G. Stanford,
• Jason D. Fowlkes,
• Kevin Lester,
• Harald Plank and
• Philip D. Rack

Beilstein J. Nanotechnol. 2015, 6, 907–918, doi:10.3762/bjnano.6.94

• process due to the isotropic carbon removal from the as-deposited materials which produces high-fidelity shape retention. Keywords: beam induced processing; direct-write; electron beam induced deposition; nano; Introduction Focused electron beam induced deposition (FEBID) is an attractive nanotechnology

• application because of its unique processing latitude and high precision resolution. FEBID uses an electron beam scanned in a specific pattern to dissociate and condense precursor material onto a substrate with high shape fidelity and a high degree of flexibility in the final form of the structure [1][2][3

• ]. Additionally, FEBID is a more gentle technique as compared to similar techniques (e.g., ion beam induced deposition (IBID)) which is beneficial for many applications. The major drawback to FEBID is the purity of the final deposits which results from unwanted precursor fragments left after dissociation. The

Fundamental edge broadening effects during focused electron beam induced nanosynthesis

• Roland Schmied,
• Jason D. Fowlkes,
• Robert Winkler,
• Phillip D. Rack and
• Harald Plank

Beilstein J. Nanotechnol. 2015, 6, 462–471, doi:10.3762/bjnano.6.47

• more complex proximity effects that significantly reduce lateral edge sharpness and thus should be avoided if desiring high lateral resolution. Keywords: focused electron beam induced deposition; nanofabrication; platinum; simulation; Introduction Focused electron beam induced deposition (FEBID) has

• attracted increasing attention due to capability to directly write functional (3D) structures with nanometer resolution [1][2][3]. Compared to lithography-based methods, FEBID does not require pre- or post-growth treatments and can be used on non-flat surfaces. This makes this technique a potential

• via a dedicated gas injection system where it adsorbs at the surface, undergoes random diffusion and desorbs again after a system-dependent residence time [1][3][4][7][8][9][10][11][12][13][14][15][16][17][18][19]. A major problem of FEBID, however, is the large amount of carbon impurities that often

In situ growth optimization in focused electron-beam induced deposition

• Paul M. Weirich,
• Marcel Winhold,
• Christian H. Schwalb and
• Michael Huth

Beilstein J. Nanotechnol. 2013, 4, 919–926, doi:10.3762/bjnano.4.103

• nanostructures that are prepared by focused electron-beam-induced deposition (FEBID). It allows us to tune the properties of the deposits towards the highest conductivity by using the time gradient of the measured in situ rate of change of conductance as the fitness parameter for the algorithm. The effectiveness

• largely suppressed. The presented technique can be applied to all beam-induced deposition processes and has great potential for a further optimization or tuning of parameters for nanostructures that are prepared by FEBID or related techniques. Keywords: electron beam induced deposition; genetic algorithm

• ; nanotechnology; tungsten; Introduction In focused electron-beam-induced deposition, FEBID in short, a (metal-)organic or inorganic volatile precursor gas, which was previously adsorbed on a substrate surface, is dissociated in the focus of an electron beam provided by a scanning (SEM) or transmission electron

Low-dose patterning of platinum nanoclusters on carbon nanotubes by focused-electron-beam-induced deposition as studied by TEM

• Xiaoxing Ke,
• Carla Bittencourt,
• Sara Bals and
• Gustaaf Van Tendeloo

Beilstein J. Nanotechnol. 2013, 4, 77–86, doi:10.3762/bjnano.4.9

• -induced deposition (FEBID) is used as a direct-write approach to decorate ultrasmall Pt nanoclusters on carbon nanotubes at selected sites in a straightforward maskless manner. The as-deposited nanostructures are studied by transmission electron microscopy (TEM) in 2D and 3D, demonstrating that the Pt

• nanoclusters are well-dispersed, covering the selected areas of the CNT surface completely. The ability of FEBID to graft nanoclusters on multiple sides, through an electron-transparent target within one step, is unique as a physical deposition method. Using high-resolution TEM we have shown that the CNT

• structure can be well preserved thanks to the low dose used in FEBID. By tuning the electron-beam parameters, the density and distribution of the nanoclusters can be controlled. The purity of as-deposited nanoclusters can be improved by low-energy electron irradiation at room temperature. Keywords: carbon

Focused electron beam induced deposition: A perspective

• Michael Huth,
• Fabrizio Porrati,
• Christian Schwalb,
• Marcel Winhold,
• Roland Sachser,
• Maja Dukic,
• Jonathan Adams and
• Georg Fantner

Beilstein J. Nanotechnol. 2012, 3, 597–619, doi:10.3762/bjnano.3.70

• ), Station 17, CH-1015 Lausanne, Switzerland 10.3762/bjnano.3.70 Abstract Background: Focused electron beam induced deposition (FEBID) is a direct-writing technique with nanometer resolution, which has received strongly increasing attention within the last decade. In FEBID a precursor previously adsorbed on

• a substrate surface is dissociated in the focus of an electron beam. After 20 years of continuous development FEBID has reached a stage at which this technique is now particularly attractive for several areas in both, basic and applied research. The present topical review addresses selected examples

• that highlight this development in the areas of charge-transport regimes in nanogranular metals close to an insulator-to-metal transition, the use of these materials for strain- and magnetic-field sensing, and the prospect of extending FEBID to multicomponent systems, such as binary alloys and

Spontaneous dissociation of Co₂(CO)₈ and autocatalytic growth of Co on SiO₂: A combined experimental and theoretical investigation

• Kaliappan Muthukumar,
• Harald O. Jeschke,
• Roser Valentí,
• Evgeniya Begun,
• Johannes Schwenk,
• Fabrizio Porrati and
• Michael Huth

Beilstein J. Nanotechnol. 2012, 3, 546–555, doi:10.3762/bjnano.3.63

• dissociation of the precursor molecule. In view of these calculations, we discuss the origin of this dissociation and the subsequent autocatalysis. Keywords: Co2(CO)8; deposition; dissociation; EBID; FEBID; precursor; radiation-induced nanostructures; Introduction In recent years, focused electron beam

• induced deposition (FEBID) has emerged as a versatile, high-resolution technique for nanostructure fabrication in contrast to the more conventional nanolithographic techniques. In FEBID, a previously adsorbed precursor gas is dissociated in the focus of an electron beam. The nonvolatile part of the

• in FEBID to obtain granular deposits with differing compositions of cobalt [11]. Electronic and physical properties, such as grain size and metal content of these deposits, depend strongly on the deposition and pretreatment conditions of the substrate. By regulating these conditions, deposits of

Radiation-induced nanostructures: Formation processes and applications

• Michael Huth

Beilstein J. Nanotechnol. 2012, 3, 533–534, doi:10.3762/bjnano.3.61

• –liquid–solid approach and the preparation of monolayers of metal–organic frameworks attached to the functional groups of a self-assembled monolayer (see, e.g., [1][2][3][4]). Not as wide-spread, but rapidly developing, is the technique of focused electron beam induced deposition (FEBID) [5]. In this

• tissue, define a principle of nanostructure formation by destructive means. But there is a deeper connection on the microscopic level. In FEBID the dominating contribution to the dissociation yield stems from low-energy electrons in the energy range between a few to several hundred electron volts

• -energy part of the energy spectrum, i.e., below about 5 keV, the biological effectiveness increases strongly. This increased effectiveness indicates a parallel to the FEBID process and points towards an analogous increase in the dissociation cross section at low electron energies. A full microscopic

Distinguishing magnetic and electrostatic interactions by a Kelvin probe force microscopy–magnetic force microscopy combination

• Miriam Jaafar,
• Oscar Iglesias-Freire,
• Luis Serrano-Ramón,
• Manuel Ricardo Ibarra,
• Jose Maria de Teresa and
• Agustina Asenjo

Beilstein J. Nanotechnol. 2011, 2, 552–560, doi:10.3762/bjnano.2.59

• Discussion In the present work we have studied cobalt nanowires grown by focused-electron-beam-induced deposition (FEBID). The sample growth was performed in a commercial dual beam® equipment using a field emission scanning electron microscope with Co2(CO)8 as gas precursor. The substrate material used in

• electron beam impinges on the substrate may not have enough energy to overcome the work function of the surface and penetrate the bulk and as a consequence they will become trapped in the neighboring area of the wires. During the FEBID deposition process some secondary electrons reach the substrate surface