Effect of native oxide on the crystal orientation contrast in SEM micrographs obtained at hundreds, tens and units of eV

0549396 - ÚPT 2022 RIV NL eng J - Článek v odborném periodiku
Mikmeková, Šárka - Aoyama, T.
Effect of native oxide on the crystal orientation contrast in SEM micrographs obtained at hundreds, tens and units of eV.
Ultramicroscopy. Roč. 220, January (2021), č. článku 113144. ISSN 0304-3991. E-ISSN 1879-2723
Grant CEP: GA TA ČR(CZ) TN01000008
Institucionální podpora: RVO:68081731
Klíčová slova: SLEEM * Crystallographic contrast * Low-energy electrons * Mirror microscopy * Work function * Surface potential
Obor OECD: Condensed matter physics (including formerly solid state physics, supercond.)
Impakt faktor: 2.994, rok: 2021
Způsob publikování: Open access
https://www.sciencedirect.com/science/article/pii/S0304399120302928?via%3Dihub

This paper aims to elucidate the effect of native air-formed oxide on the crystallographic contrast between differently oriented copper grains in scanning electron microscope images obtained at energies from 0 eV up to 1 keV. The contrast between the Cu grains is strongly affected by the presence of native oxide. The crystallographic orientation contrast between the grains without covering the native oxide layer is relatively weak at hundreds of eV, negligible at tens of eV, and dramatically increases at energies below 10 eV. At extremely low landing energies, say below similar to 1 eV, the surface potential differences caused by work function variations between the differently oriented Cu grains affect the primary electrons, which enables us to obtain the micrographs with high crystallographic contrast. This contrast becomes surprisingly visible even if the grains are covered by a several nm thick native oxide layer. The presence of the native air-formed oxide layer on the Cu surface is inconsiderable for the contrast formation at energies close to the mirror conditions (< 1 eV). The surface potential differences originating in the substrate can affect the incident electrons through the native oxide film situated on the Cu surface. Scanning low-energy electron microscopy is a powerful tool for mapping local work function differences with a spatial resolution slightly better than 30 nm due to high sensitivity to local electrical potentials.
Trvalý link: http://hdl.handle.net/11104/0325415