In the present paper the influence of oxygen rf plasma treatment on the pro
perties of both Si and SiO2 sides of the wet thermal SiO2/Si interface was
investigated. The defect concentrations of the oxide charge, dopant level a
nd the interface trap density were obtained from capacitance-voltage (C-V)
characterization. The amount of hydrogen trapped in the interfacial region
was estimated from changes in the doping density of the silicon substrate.
Generation and passivation of electrically active defect centers were found
depending on the substrate temperature and the amount of hydrogen. Modific
ation of the oxide and interface between Si and wet SiO2 is inferred. Plasm
a promoted release from the oxide bulk of hydrogen species is suggested.