Electron-beam-induced modification of gold microparticles in an SEM

TL;DR

This study demonstrates a low-voltage electron-beam technique in SEM to modify gold microparticles, revealing localized heating effects that enable melting and vaporization, expanding the versatility of electron-beam material processing.

Contribution

It introduces a novel low-energy e-beam method in SEM for modifying microparticles, bridging e-beam lithography and welding with detailed interaction analysis.

Findings

Inelastic electron-matter interactions cause localized heating.

Microparticles undergo melting and vaporization under the e-beam.

Simulations support the thermal mechanism of modification.

Abstract

Electron-beam-induced conversion of materials in a transmission electron microscope uses the high power density of a localized electron beam of acceleration voltages above 100 kV as an energy source to transform matter at the sub-micron scale. Here, the e-beam-induced transformation of precursor microparticles employing a low-energy e-beam with an acceleration voltage of 30 kV in a scanning electron microscope is developed to increase the versatility and efficiency of the technique. Under these conditions, the technique can be classified between e-beam lithography, where the e-beam is used to mill holes in or grow some different material onto a substrate, and e-beam welding, where matter can be welded together when overcoming the melting phase. Modifying gold microparticles on an amorphous SiOx substrate reveals the dominant role of inelastic electron-matter interaction and subsequent localized heating for the observed melting and vaporization of the precursor microparticles under the electron beam. Monte-Carlo scattering simulations and thermodynamic modeling further support the findings.