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 + 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. C 2015 AIP Publishing LLC. [http://dx.

Thermocapillary convection in a laser-heated Ni melt pool: A molecular dynamics study

“…Nanometric-scale manufacturing with focused ion beams is also developing fast for applications such as forming nanopores in thin films for DNA sequencing. Atomic-scale thermocapillary flow was demonstrated in this process by means of MD simulations [26].…”

Development of a numerical model for Marangoni convection in the micro-scale environment

“…However, it was also shown that such a convective flow may also occur in the micro-scale environment of the applications of manufacturing micro-and nanodevices. The works of Murata and Mochizuki, 2006;Maier et al, 2012;Das et al, 2015a;Das, 2015b have shown that Marangoni convection develops even in the nano-meter scale.…”