Atomic-step observation at buried SiO2/Si(111) interfaces by scanning reflection electron microscopy

Scanning reflection electron microscopy is used to obtain plan-view atomic step images of buried SiO2/Si(111) interfaces and is combined with X-ray photoelectron spectroscopy. Under various oxidation conditions (with a <0.9-nm oxide thickness), the results are consistent with the layer-by-layer oxidation model, where the oxidation is governed by random site oxidation and the subsequent preferential reaction of Si atoms that already have Si-O bonds. SREM is also applied to image interfacial stress, and to show that the stress is uniform even at the interfacial steps. (C) 1997 Elsevier Science B.V.