ABSTRACT
The most straightforward way to prepare a thin silica film is thermal oxidation of pure Si substrates and Si-containing alloys, since Si will most likely segregate at surface and be oxidized. Silicon crystallizes in a diamond cubic crystal structure. Being sensitive to the details of Si-O bonding configuration, infrared spectroscopy was intensively used to study the SiO2/Si interfaces. In addition to thermal Si oxidation, which uses molecular oxygen as oxidizing agent, the formation of ultrathin silica films on a Si wafer has been observed with highly concentrated nitric acid vapor at 100-200°C. In general, oxidation kinetics of SiC surfaces showed similar behavior to Si and was originally described within the Deal-Grove model applied to oxidation of pure Si, although oxygen has a lower solubility in SiC than in Si.
