Initial stage of oxidation of Si(100) surfaces in dry oxygen

The initial stage of oxidation of hydrogen-terminated Si(100) surfaces in dry oxygen gas has been studied using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. Heating the wafer up to 300°C in vacuum caused the desorption of hydrogen primarily from defects such as steps on the surface, and the following preoxidation in dry oxygen at 300°C progressed therein. The preoxides thus formed on surfaces were stable during thermal oxidation at 900°C, preventing an increase of the surface microroughness caused during heating the wafer at high temperatures. Such preoxides prior to thermal oxidation were also found to cause structural modification of very thin oxide films.