Defects in SiO₂/Si Structures Formed by Dry Thermal Oxidation of RF Hydrogen Plasma Cleaned Si

The present paper reports characterization of the defects in ultrathin (∼10 nm) oxides grown by low-temperature (850°C) thermal oxidation of hydrogen plasma hydrogenated (100)Si and (111)Si substrates. Electrically active defects, studied by analyzing the frequency dispersion of the capacitance-voltage (C-V) and conductance-voltage (G-V) characteristics are dominated by distinct defects, related to interface traps with different localized energy levels in the Si bandgap, border traps and bulk Si traps. Precursors of the trapping centers are defects in a thin, less dense Si surface region containing voids, which is formed during hydrogenation and is incorporated into the growing oxide layer. Oxidation-induced stress level, evaluated from ellipsometric and electroreflectance data analysis, is in the order of 10⁸ N/m².