The Initial Stages of the Thermal Oxidation of Si(001) 2×1 Surface Studied by Scanning Tunneling Microscopy

The initial stages of the thermal oxidation of Si(001) 2×1 surface were studied by scanning tunneling microscopy. The O2 exposure at 600 °C produced Si islands and initial forms of oxides. The oxides appeared as ‘‘dark sites,’’ ‘‘sequence of dots,’’ and ‘‘dots with dark surroundings.’’ Among the oxides, most of the dark sites were removed by the successive heating at 600 °C, while the sequence of dots and the dots with dark surroundings remained. All the oxides were removed by the successive heating at 800 °C. The thermal oxidation of Si(001) 2×1 surface is discussed in terms of these sites.