Skip to main content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Using a Modular Aperture System to Obtain Annular Dark-Field Image Intensity Distributions as a Function of Scattering Angle.

Published

Author(s)

Jason D. Holm

Abstract

In this contribution, 10 nm-thick non-stoichiometric silicon nitride films were examined in a scanning electron microscope (SEM) using a zero-dimensional solid-state transmission electron detector equipped with a modular aperture system. Effects of several parameters on annular dark-field image intensity distributions as a function of detector acceptance angle were investigated, including primary electron energy, transmission detector acceptance angle and span, and beam convergence angle. Results showed that intensity distributions varied significantly with STEM detector acceptance angle span, and that even a modestly wide aperture integrates over a large signal range and can hide distribution details. Distributions collected with narrow apertures and normalized to acceptance angle span exhibited distinct broad peaks that shifted to greater angles with decreasing primary electron energy. Beam convergence angle had a smaller effect on the distributions, but sample charging was problematic when large primary electron beam apertures were used.
Citation
Ultramicroscopy
Volume
195

Keywords

STEM-in-SEM, transmission-SEM, aperture, image intensity distribution
Created June 15, 2018, Updated August 28, 2019