MULTIPLE SCATTERING CALCULATIONS OF GBMEED

Abstract

A method for computing grazing-incidence backscattering medium energy (1–3 keV) electron diffraction (GBMEED) is presented. The technique was recently proposed as a structural tool exhibiting diffraction effects resembling those of XPD. In GBMEED the intensity of quasielastically thermal diffuse scattering is measured at large scattering angles such that different atoms can be assumed to vibrate independently, and thus represent localized sources for diffuse scattering in the surface layers. The basis of the calculations is the multiple scattering theory of diffuse RHEED adopted to the medium energy case with a vibrating atom as source of diffuse scattering. Calculated plots of the intensity versus azimuthal/polar exit angle for an In overlayer on Si(111) show the forward focusing effect along the source-scatterer direction (well known from XPD) and further fine structure.