Scattering intensity distribution dependence on collection angles in annular dark-field STEM-in-SEM images

Abstract

A scanning electron microscope (SEM) equipped with a zero-dimensional solid-state transmission electron detector and a modular aperture system was used to examine the relationship between annular dark-field image intensity distributions and several imaging parameters. The effects of primary electron energy, transmission detector acceptance angle and span, and beam convergence angle on scattering intensity distributions exhibited by a 10 nm thick amorphous silicon nitride film were examined. Results showed that angular distributions varied significantly with only minor changes in transmission detector acceptance angle span. Distributions collected with narrow apertures and normalized to acceptance angle span exhibited broad, distinct peaks that shifted to greater angles with decreasing primary electron energy, while even modestly wide apertures resulted in large distribution variations. A comparison between scattering distributions (i.e., diffraction patterns) quantified using the modular aperture system and a two-dimensional pixelated detector demonstrated that equivalent information could be obtained with either detector for this sample.