Ultrathin gate oxide with a reduced transition layer grown by plasma-assisted oxidation

High-resolution x-ray photoemission spectroscopy and medium energy ion scattering spectroscopy (MEIS) were used for the investigation of ultrathin SiO₂ grown by plasma-assisted oxidation. The plasma oxide grown at the low temperature of 400°C was found to have thin transition layer as compared to conventional thermal oxide. The plasma oxide was used as gate dielectric for reducing the equivalent oxide thickness (EOT) by 0.5 Å without the increase of the gate leakage current. The results show that the thinner transition layer in the plasma oxide decreases the gate leakage current effectively along with the improvement the reliability of the gate oxide.