RF Power Effect of Post-Deposition Oxygen Plasma Treatment on HfO2 Gate Dielectrics

The RF power effect of post-deposition O₂ plasma treatment on the physical, electrical characteristics, and reliability performance of high-k HfO₂ dielectric films were investigated in this study. Increasing RF power in post-deposition O₂ plasma treatment results in a stoichiometric HfO₂ film, but leading to a thinner interfacial layer with a new Hf-Si bond. Additionally, the electrical performance and reliability of high-k HfO₂ dielectric films were related to the RF power in post-deposition O₂ plasma treatment. As RF power is less than 50 W, the leakage current density and time-to-breakdown were improved as compared to those of un-treated samples. However, these properties were continuously degraded with an increase of RF power due to plasma damage induced by oxygen active spices in a O₂ plasma environment. Therefore, the post-deposition O₂ plasma treatment is benefit in the improvement of HfO₂ gate dielectric properties, but the plasma power is needed to be well controlled.