title: Materials characterisation by angle-resolved scanning transmission electron microscopy.
abstract: Solid-state properties such as strain or chemical composition often leave characteristic fingerprints in the angular dependence of electron scattering. Scanning transmission electron microscopy (STEM) is dedicated to probe scattered intensity with atomic resolution, but it drastically lacks angular resolution. Here we report both a setup to exploit the explicit angular dependence of scattered intensity and applications of angle-resolved STEM to semiconductor nanostructures. Our method is applied to measure nitrogen content and specimen thickness in a GaNxAs1-xlayer independently at atomic resolution by evaluating two dedicated angular intervals. We demonstrate contrast formation due to strain and composition in a Si- based metal-oxide semiconductor field effect transistor (MOSFET) with GexSi1-xstressors as a function of the angles used for imaging. To shed light on the validity of current theoretical approaches this data is compared with theory, namely the Rutherford approach and contemporary multislice simulations. Inconsistency is found for the Rutherford model in the whole angular range of 16-255 mrad. Contrary, the multislice simulations are applicable for angles larger than 35 mrad whereas a significant mismatch is observed at lower angles. This limitation of established simulations is discussed particularly on the basis of inelastic scattering.
authors.affiliation: Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359, Bremen, Germany.
authors.forename: Knut
authors.initials: K
authors.lastname: Müller-Caspary
authors.affiliation: Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359, Bremen, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Oppermann
authors.affiliation: Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359, Bremen, Germany.
authors.forename: Tim
authors.initials: T
authors.lastname: Grieb
authors.affiliation: Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359, Bremen, Germany.
authors.forename: Florian F
authors.initials: FF
authors.lastname: Krause
authors.affiliation: Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359, Bremen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Rosenauer
authors.affiliation: Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359, Bremen, Germany.
authors.forename: Marco
authors.initials: M
authors.lastname: Schowalter
authors.affiliation: Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359, Bremen, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Mehrtens
authors.affiliation: Faculty of Physics and Materials Science Center, Philipps Universität Marburg, Hans-Meerwein-Straße, 35032, Marburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Beyer
authors.affiliation: Faculty of Physics and Materials Science Center, Philipps Universität Marburg, Hans-Meerwein-Straße, 35032, Marburg, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Volz
authors.affiliation: GLOBALFOUNDRIES Dresden Module 1, Wilschdorfer Landstraße 101, 01109, Dresden, Germany.
authors.forename: Pavel
authors.initials: P
authors.lastname: Potapov