Heteroepitaxial interfaces are important because they determine the performance of devices such that career mobility is sensitive to the distribution of roughness, strain and composition at the interface. High-angle annular dark field imaging in scanning transmission electron microscopy has been utilized to capture them at an atomic scale. For precise identification of atomic column positions, a technique has been proposed to average multiple image frames taken at a high scanning rate by their positional alignment for increasing signal-to-noise ratio. However, the positional alignment between frames is sometimes incorrectly estimated because of the almost perfect periodic structure at the interfaces. Here, we developed an approach for precise positional alignment, where the images are first aligned by two consecutive images and then are aligned more precisely against the integrated image of the first alignment. We demonstrated our method by applying it to the heterointerface of Si0.8Ge0.2 (Si: silicon, Ge: germanium) epitaxial thin films on a Si substrate.
Keywords: atom-resolved HAADF imaging; heteroepitaxial interface; image processing; positional alignment.
© The Author(s) 2024. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site–for further information please contact journals.permissions@oup.com.