Influence of the initial Si surface structures on SiO2/Si(111) interfaces and thermal decomposition of the oxide films

We used scanning reflection electron microscopy (SREM) and Auger electron spectroscopy (AES) to investigate the influence of the surface structures of initial Si(lll) substrates on oxidation and the thermal decomposition processes. The Si(111) surfaces, on which a reconstructed 7 x 7 domain and a disordered 1 x 1 phase coexisted, were oxidized to less than 1 Mm thick by molecular oxygen exposure. Our SREM observation showed that traces of these domains were preserved at the SiO2/Si(111) interfaces after the surface reconstruction disappeared. We also confirmed that thermal decomposition of the oxide layers grown at the 1 x 1 region was promoted compared to that grown at the 7 x 7 reconstructed area. These results mean that the atomic structure at the interface and stability against thermal decomposition of the oxide him are affected by the initial surface structures. (C) 1998 Elsevier Science B.V. All rights reserved.