RF Power Effect of Post-Deposition Oxygen Treatment on HfO_2 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 HfO_2 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 HfO_2 film, but led to a thinner interfacial layer and the formation of new Hf-Si bonds. Additionally, the electrical characteristics and reliability performance of HfO_2 dielectric films were significantly impacted by the RF power of the post-deposition O_2 plasma treatment. As RF power is less than 30 W, the leakage current density and time-to-breakdown of the O_2 plasma-treated HfO_2 films were improved in comparison with those of the as-deposited samples. However, further increasing RF power exceeding 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 HfO_2 dielectric films can effectively improve the dielectric's properties. However, the applied RF power is an essential controlling parameter, avoiding serious plasma damage occurrence.