Characterization of interface electronic properties of low-temperature ultrathin oxides and oxynitrides formed on Si(111) surfaces by contactless capacitance-voltage and photoluminescence methods

Using contactless capacitance-voltage (C-V), photoluminescence surface state spectroscopy (PLS(3)) and X-ray photoelectron spectroscopy techniques, interface electronic properties of ultrathin-insulator films formed on Si (111) surfaces at low temperatures were characterized, paying particular attention to the effect of nitrogen-related plasmas. Hydrogen termination was used as the initial surface treatment. Low-temperature (400 degrees C) thermal oxidation processes produced oxide/Si interfaces with a high-density of interface states that caused limited C-V variation and low PL efficiency. Treatment of low-temperature thermally grown oxides in electron cyclotron resonance (ECR) N-2 plasma had no effect on the interface properties. On the other hand, marked enhancement of C-V variation and PL efficiency was achieved at the surface after ECR N2O-plasma oxynitridation at 400 degrees C. The correlation between chemical and electronic properties of the interfaces is discussed.