Effect of RF power of post-deposition oxygen treatment on HfO2 gate dielectrics

摘要

The radio frequency (RF) power effect of post-deposition O-2 plasma treatment on the physical, electrical, and reliability characteristics of high-k HfO2 dielectric films was comprehensively investigated in this study. The experimental results indicated that increasing the RF power of post-deposition O-2 plasma treatment resulted in a stoichiometric HfO2 film, but led to a thinner interfacial layer and the formation of new Hf-Si bonds. Additionally, the electrical performance and reliability of HfO2 dielectric films were significantly impacted by the RF power of the post-deposition O-2 plasma treatment. As the RF power is less than 30 W, the leakage current density and time-to-breakdown of the O-2 plasma-treated HfO2 films were improved in comparison with those of the as-deposited samples. However, further increasing RF power to exceed 50 W would cause the continuous degradation in the electrical performance and reliability due to the plasma damage induced by oxygen active spices in a plasma environment. Therefore, performing a post-deposition O-2 plasma treatment process on the as-deposited HfO2 dielectric films can effectively improve the dielectric's properties. However, the applied RF power is an essential controlling parameter, avoiding serious plasma damage occurrence. (C) 2014 Elsevier B.V. All rights reserved.