Step characterization on vicinal Si surfaces by reflection high-energy electron diffraction at arbitrary azimuths

Based on kinematic theory, we demonstrate the reflection high-energy electron diffraction (RHEED) characterization of the step period on vicinal Si surfaces from the separation of the specular beam split spots at an arbitrary azimuth. Increasing the azimuthal angle between the electron beam and the step direction enlarges the separation between the split spots and thus enables the split spot separation discernible even at large step periods. Vicinal Si(001) surfaces with miscuts ranging from 0.32° (nearly flat) up to 10° as well as a Si(113) surface with step periods up to about 100 nm have been successfully analyzed. It is found that a well prepared vicinal Si(001) surface always shows a double-layer period by RHEED.