Fabrication of SiO2 thin films by ECR plasma anodization

Anodization of single-crystalline silicon was carried out under microwave plasma created by electron cyclotron resonance (ECR), and the anodization characteristic and oxide film property were evaluated. The growth rate of the oxide film depended strongly on the oxygen pressure and the growth rate reached the maximum under relatively high oxygen pressure. Since the plasma parameters and substrate temperature were dependent on the oxygen pressure, the oxidation was thought to be dependent on the supply of oxygen atoms from plasma and the generation of silicon atoms and dangling bonds at the Si-oxide interface. The X-ray photoelectron spectra revealed the formation of stoichiometric SiO2. This result provided insight into the oxide growth process. In addition, the electric conduction in an MOS device formed using this oxide was investigated. As a result, it was found that the dc high field conduction prior to the self-healing breakdown was based on the tunneling of electrons injected by Schottky emission through the oxide. Also, the negative resistance observed after the self-healing breakdown was caused by the formation of space charges caused by the impurity ions.