Observations of cleaned and oxygen exposed surfaces of silicon and germanium by reflection high energy electron diffraction

Abstract

The {111} and {100} surfaces of germanium and the {111} surface of silicon, cleaned in ultra-high vacuum by argon ion bombardment and annealing, were studied by the HEED technique. Fractional- and integral-order streak diffraction patterns were observed which were consistent with the Ge (111) 8, Ge (100) 4 and Si (111) 7 LEED, clean surface, spot patterns. An anomaly was observed between the HEED and other workers' LEED observations of the {100} germanium surface. Oxygen adsorption on the cleaned germanium surfaces was found to extinguish all fractional-order beams 10 −5 Torr-min.