Evaluation of real-space images of Pt-single crystals produced by backscattered electrons in the kiloelectronvolt range

(Received 8 March 1994, revised 2 May 1994, accepted 31 May 1994)

Abstract
The strongly forward-peaked nature of electron-atom scattering in the kiloelectronvolt range is responsible for the fact, that electrons which are backscattered from single crystals loosing less than 5% of their energy in the scattering process, show a strong rise of intensity along directions defined by atomic rows. The spatial imaging of such electrons, reveals the crystallography of the near-surface regions in real-space. The surface sensitivity of this imaging method with backscattered electrons, can be influenced by choosing the angle of the primary-electron incidence and the energy of the incident primary-electrons. In this paper, an evaluation concept is displayed which allows to determine the mean depth of the image-forming electron sources and scattering atoms, if the single crystal structure of the measured sample is already known. The model also enables the identification of unknown near-surface structures, taking into account crystallographical restrictions.