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Title: Atomic-scale thermocapillary flow in focused ion beam milling

Abstract

Focused ion beams provide a means of nanometer-scale manufacturing and material processing, which is used for applications such as forming nanometer-scale pores in thin films for DNA sequencing. We investigate such a configuration with Ga{sup +} bombardment of a Si thin-film target using molecular dynamics simulation. For a range of ion intensities in a realistic configuration, a recirculating melt region develops, which is seen to flow with a symmetrical pattern, counter to how it would flow were it driven by the ion momentum flux. Such flow is potentially important for the shape and composition of the formed structures. Relevant stress scales and estimated physical properties of silicon under these extreme conditions support the importance thermocapillary effects. A flow model with Marangoni forcing, based upon the temperature gradient and geometry from the atomistic simulation, indeed reproduces the flow and thus could be used to anticipate such flows and their influence in applications.

Authors:
; ;  [1]
  1. Mechanical Science and Engineering and Aerospace Engineering, University of Illinois at Urbana–Champaign, 1206 West Green Street MC-244, Urbana, Illinois 61801 (United States)
Publication Date:
OSTI Identifier:
22403228
Resource Type:
Journal Article
Journal Name:
Physics of Fluids (1994)
Additional Journal Information:
Journal Volume: 27; Journal Issue: 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-6631
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 74 ATOMIC AND MOLECULAR PHYSICS; CAPILLARY FLOW; COMPUTERIZED SIMULATION; DNA SEQUENCING; FLOW MODELS; GALLIUM IONS; GEOMETRY; ION BEAMS; MILLING; MOLECULAR DYNAMICS METHOD; PHYSICAL PROPERTIES; PROCESSING; SILICON; STRESSES; TEMPERATURE GRADIENTS; THIN FILMS

Citation Formats

Das, K., Johnson, H. T., and Freund, J. B., E-mail: jbfreund@illinois.edu. Atomic-scale thermocapillary flow in focused ion beam milling. United States: N. p., 2015. Web. doi:10.1063/1.4919782.
Das, K., Johnson, H. T., & Freund, J. B., E-mail: jbfreund@illinois.edu. Atomic-scale thermocapillary flow in focused ion beam milling. United States. doi:10.1063/1.4919782.
Das, K., Johnson, H. T., and Freund, J. B., E-mail: jbfreund@illinois.edu. Fri . "Atomic-scale thermocapillary flow in focused ion beam milling". United States. doi:10.1063/1.4919782.
@article{osti_22403228,
title = {Atomic-scale thermocapillary flow in focused ion beam milling},
author = {Das, K. and Johnson, H. T. and Freund, J. B., E-mail: jbfreund@illinois.edu},
abstractNote = {Focused ion beams provide a means of nanometer-scale manufacturing and material processing, which is used for applications such as forming nanometer-scale pores in thin films for DNA sequencing. We investigate such a configuration with Ga{sup +} bombardment of a Si thin-film target using molecular dynamics simulation. For a range of ion intensities in a realistic configuration, a recirculating melt region develops, which is seen to flow with a symmetrical pattern, counter to how it would flow were it driven by the ion momentum flux. Such flow is potentially important for the shape and composition of the formed structures. Relevant stress scales and estimated physical properties of silicon under these extreme conditions support the importance thermocapillary effects. A flow model with Marangoni forcing, based upon the temperature gradient and geometry from the atomistic simulation, indeed reproduces the flow and thus could be used to anticipate such flows and their influence in applications.},
doi = {10.1063/1.4919782},
journal = {Physics of Fluids (1994)},
issn = {1070-6631},
number = 5,
volume = 27,
place = {United States},
year = {2015},
month = {5}
}