Periodic Changes in SiO₂/Si(111) Interface Structures with Progress of Thermal Oxidation

Abstract

Changes in SiO 2 /Si(111) interface structures during the progress of oxidation through 0.5-nm-thick preoxide were investigated at 600 and 800°C in dry oxygen with a pressure of 133 Pa by measuring oxidation-induced changes in Si 2p photoelectron spectra. The following results are obtained: 1) at 800°C, oxidation reaction occurs monolayer by monolayer at the interface, however, 2) monoatotnic steps exist at the interface in every stage of oxidation.