Nanopillar growth by focused helium ion-beam-induced deposition
article
A 25 keV focused helium ion beam has been used to grow PtC nanopillars on a silicon substrate by beam-induced decomposition of a (CH<sub>3</sub>) <sub>3</sub>Pt(C<sub>P</sub>CH<sub>3</sub>) precursor gas. The ion beam diameter was about 1 nm. The observed relatively high growth rates suggest that electronic excitation is the dominant mechanism in helium ion-beam-induced deposition. Pillars grown at low beam currents are narrow and have sharp tips. For a constant dose, the pillar height decreases with increasing current, pointing to depletion of precursor molecules at the beam impact site. Furthermore, the diameter increases rapidly and the total pillar volume decreases slowly with increasing current. Monte Carlo simulations have been performed with realistic values for the fundamental deposition processes. The simulation results are in good agreement with experimental observations. In particular, they reproduce the current dependences of the vertical and lateral growth rates and of the volumetric deposition efficiency. Furthermore, the simulations reveal that the vertical pillar growth is due to type-1 secondary electrons and primary ions, while the lateral outgrowth is due to type-2 secondary electrons and scattered ions. © 2010 IOP Publishing Ltd.
Topics
Beam diametersBeam impactCurrent dependenceDeposition efficienciesDeposition processDominant mechanismElectronic excitationExperimental observationHelium ion beamsHigh growth rateLateral growthLateral outgrowthsLow beamMonte Carlo SimulationNanopillarsPrecursor moleculesPrimary ionsSecondary electronsSharp tipSilicon substratesSimulation resultComputer simulationMonte Carlo methodsPlatinumPlatinum compoundsSecondary emissionSuperconducting materials
TNO Identifier
425129
ISSN
09574484
Source
Nanotechnology, 21(45)
Article nr.
No.: 455302
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