Thickness profiling of electron transparent aluminium alloy foil using convergent beam electron diffraction

Abstract

Convergent beam electron diffraction (CBED) was used to profile the thickness of aluminium alloys foils prepared by using the twinjet electropolishing method. The two-beam CBED condition was obtained by exciting the $\left\{200\right\}$ and $\left\{111\right\}$ aluminium diffracted g-vector. The aluminium alloy foil thicknesses were calculated at different distances from the sample hole edge. In areas where only one Kossel-Möllenstedt (K-M) minima fringe was obtained, the thickness was determined by matching the experimental with simulated convergent beam diffraction patterns. In areas far away from the sample edge, the thickness of foils was high enough to generate at least two (K-M) minima fringes, required for linear regression fitting.

Keywords: Kossel-Möllenstedt (K-M) fringe; aluminium alloy; convergent beam electron diffraction (CEBD); extinction distance; thickness fringe; transmission electron microscopy (TEM); two-beam condition.