Atomic Lineation of Products during Oxidation of Si(111)-7 × 7 Surface Using O2 at 300 K

Abstract

Despite much attention for forming a uniform oxide film with a few atomic layers in modern Si semiconductor industry, the surface distribution and the chemical analysis of oxides have not been clear. In situ observation of an Si(111)-7 × 7 surface during exposing to O2 at 300 K was carried out using X-ray photoelectron spectroscopy, low-energy electron diffraction, and scanning tunneling microscope. Atomic lineation of products on the Si adatoms in the faulted-half side of the Si(111)-7 × 7 surface was revealed. We clarified that the minimum thickness of the oxide film, which covers the overall Si surface, was 0.35 nm. This study provides the physical picture of oxide-film formation mechanisms, which involves a mobile O2 on the surface and suggests the possibility to fabricate 1D atomic oxides.