Electrical characteristics of high-quality sub-25-Å oxides grown by ultraviolet ozone exposure at low temperature

We have developed a method for controllably and reproducibly growing self-limiting ultrathin oxides with excellent electrical properties in the range similar to 10-25 Angstrom thick at temperatures ranging from 25 to 600 degrees C, respectively, using an ultraviolet ozone (UVO3) oxidation process. The self-limiting thickness depends primarily on the substrate temperature, allowing ultrathin oxide growth with precision and reproducibility using this UVO3 process. Oxides grown by this method are comparable in electrical quality to thermal oxides, with similar leakage current densities and breakdown fields E-BD > 10 MV/cm. Current-voltage (I-V) analysis shows oxide thickness uniformity to within 1% from center to edge of a 4-in wafer. Capacitance-voltage (C-V) characterization of similar to 25 Angstrom oxides shows excellent saturation behavior, with low midgap interface trap densities and no hysteresis or dispersion.