Electron-Beam-Induced Deposition as a Technique for Analysis of Precursor Molecule Diffusion Barriers and Prefactors

Cullen, Jared; Lobo, Charlene; Ford, Michael J.; Toth, Milos

doi:10.1021/acsami.5b06341

Cited by 10 publications

(7 citation statements)

References 34 publications

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“…1D model predictions preempted the integration of a 3D beam heating simulation to our 3D FEBID solver . The effect of electron-beam heating during FEBID has been previously recognized for various materials, ,− and the 3D simulations reported here including the heating effect are consistent with previous observations. Simulations with the enhanced capability revealed the important role that heat transfer plays in dictating the final deposit geometry: a thermal gradient develops in the deposit that induces an opposing precursor concentration gradient.…”

supporting

confidence: 86%

“…An updated value of E a = 0.62 eV (dashed line) produced simulation results that predicted 3D FEBID experiments and is taken as an estimate of the E a for the MeCpPt IV Me 3 –PtC x interface. Surface diffusion D ( T ) is less sensitive to temperature changes (solid blue line) based on data provided in ref with D o = 42 μm 2 /s and E a( D ) = 122 meV, at least when compared to τ( T ).…”

Section: Resultsmentioning

confidence: 99%

“…33 Considering temperature changes predicted by the 1D heating model ΔT ≈ 10 K, a decrease in τ(T) exceeding 50% is expected. Please note that the Cullen/Toth 22,23 reports of the implications of the temperature-dependent behavior of this precursor and its participation in FEBID served as an extremely valuable resource in the development the current work ultimately leading to the exploration of the beam heating effect. 22 Furthermore, Utke 26 identified the importance of considering τ(T), while Randolph also identified the importance of τ(T) during TEOS deposition using FEBID.…”

Section: Resultsmentioning

confidence: 99%

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Impact of Electron-Beam Heating during 3D Nanoprinting

et al. 2019

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An artifact limiting the reproduction of three-dimensional (3D) designs using nanoprinting has been quantified. Beaminduced heating was determined through complementary experiments, models, and simulations to affect the deposition rate during the 3D nanoprinting of mesh objects using focused electron beam induced deposition (FEBID). The mesh objects are constructed using interconnected nanowires. During nanowire growth, the beam interaction driving deposition also causes local heating. The temperature at the beam impact region progressively rises as thermal resistance increases with nanowire growth. Heat dissipation resembles the classical mode of heat transfer from extended surfaces; heat must flow through the mesh object to reach the substrate sink. Simulations reveal that beam heating causes an increase in the rate of precursor desorption at the BIR, causing a concomitant decrease in the deposition rate, overwhelming an increase in the deposition rate driven by thermally enhanced precursor surface diffusion. Temperature changes as small as 10 K produce noticeable changes in deposit geometry; nanowires appear to deflect and curve toward the substrate because the vertical growth rate decreases. The 3D FEBID naturally ensues from the substrate surface upward, inducing a vertical temperature gradient along the deposit. Simulations, experiments, temperature-controlled studies, and process current monitoring all confirm the cause of nanowire distortion as beam-induced heating while also revealing the rate-determining physics governing the final deposit shape.

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supporting

confidence: 86%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Impact of Electron-Beam Heating during 3D Nanoprinting

et al. 2019

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“…Recent work by Cullen and collaborators [20,24] has shown how both the activation energies and pre-exponential factors for desorption and diffusion can be deduced from FEBID experiments under stationary beam conditions if certain prerequisites are fulfilled. This approach may also be applied to the CoFe-and Nb-precursor to deduce the temperature dependence of D. This will then allow to take properly into account how beam-induced heating might change the growth rates for 3D growth using the CoFe-and Nb-precursor due to increased desorption and faster diffusion, as was previously investigated for the Pt-precursor [25].…”

Section: Discussionmentioning

confidence: 99%

Temperature-Dependent Growth Characteristics of Nb- and CoFe-Based Nanostructures by Direct-Write Using Focused Electron Beam-Induced Deposition

et al. 2019

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Focused electron and ion beam-induced deposition (FEBID/FIBID) are direct-write techniques with particular advantages in three-dimensional (3D) fabrication of ferromagnetic or superconducting nanostructures. Recently, two novel precursors, HCo 3 Fe(CO) 12 and Nb(NMe 3 ) 2 (N-t-Bu), were introduced, resulting in fully metallic CoFe ferromagnetic alloys by FEBID and superconducting NbC by FIBID, respectively. In order to properly define the writing strategy for the fabrication of 3D structures using these precursors, their temperature-dependent average residence time on the substrate and growing deposit needs to be known. This is a prerequisite for employing the simulation-guided 3D computer aided design (CAD) approach to FEBID/FIBID, which was introduced recently. We fabricated a series of rectangular-shaped deposits by FEBID at different substrate temperatures between 5 ° C and 24 ° C using the precursors and extracted the activation energy for precursor desorption and the pre-exponential factor from the measured heights of the deposits using the continuum growth model of FEBID based on the reaction-diffusion equation for the adsorbed precursor.

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“…The equilibrium precursor surface coverage (θ ο ) for the flat PtC 5 surface for our gas injection system was calculated to be 0.73 when the precursor nozzle was oriented at 38°with respect to the substrate normal vector and the precursor capillary tube. Parameters necessary for this calculation were (1) the precursor sticking probability (unknown, assumed δ = 1), (2) the surface diffusion coefficient 0.4 μm 2 /s of MeCpPt IV Me 3 31 and (3) the mean surface residence time (τ) of 100 μs for the MeCpPt IV Me 3 molecule adsorbed on PtC 5 . 26 Regarding the parameter (τ), an experimentally derived value of ∼29 μs is reported in the literature, 32 yet we have found that by increasing the parameter to 100 μs a better fit to our experiments is achieved.…”

Section: Simulation Parametersmentioning

confidence: 99%

Simulation-Guided 3D Nanomanufacturing via Focused Electron Beam Induced Deposition

et al. 2016

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Focused electron beam induced deposition (FEBID) is one of the few techniques that enables direct-write synthesis of free-standing 3D nanostructures. While the fabrication of simple architectures such as vertical or curving nanowires has been achieved by simple trial and error, processing complex 3D structures is not tractable with this approach. In part, this is due to the dynamic interplay between electron-solid interactions and the transient spatial distribution of absorbed precursor molecules on the solid surface. Here, we demonstrate the ability to controllably deposit 3D lattice structures at the micro/nanoscale, which have received recent interest owing to superior mechanical and optical properties. A hybrid Monte Carlo-continuum simulation is briefly overviewed, and subsequently FEBID experiments and simulations are directly compared. Finally, a 3D computer-aided design (CAD) program is introduced, which generates the beam parameters necessary for FEBID by both simulation and experiment. Using this approach, we demonstrate the fabrication of various 3D lattice structures using Pt-, Au-, and W-based precursors.

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Electron-Beam-Induced Deposition as a Technique for Analysis of Precursor Molecule Diffusion Barriers and Prefactors

Cited by 10 publications

References 34 publications

Impact of Electron-Beam Heating during 3D Nanoprinting

Impact of Electron-Beam Heating during 3D Nanoprinting

Temperature-Dependent Growth Characteristics of Nb- and CoFe-Based Nanostructures by Direct-Write Using Focused Electron Beam-Induced Deposition

Simulation-Guided 3D Nanomanufacturing via Focused Electron Beam Induced Deposition

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