A novel hydrogen rich interfacial layer to downscale high-K dielectrics

High temperature RTO (Rapid Thermal Oxidation) process can get good quality but growth rate was too fast to get a controllable ultra-thin SiO₂ as interfacial layer (IL) for high-K gate dielectrics application. In this paper, we investigated the physical and electrical properties of IL film obtained by different oxidation gas ratio, temperature, pressure. We found high temperature (>1080C) and hydrogen rich environment perform ultra-thin optical thickness (4A) while sustaining high quality characteristics. In accordance with Le Chatelier´s principle, high hydrogen concentration drive SiO₂ decomposed to SiO gas. Based on this method, we can demonstrate good quality IL and simultaneously optical thickness can be downscaled to achieve superior electrical performance. Hydrogen rich and high temperature SiO₂ adding wet clean process with Hafnium-based high-K dielectrics demonstrate best compromising EOT 10A as well as 30% gate leakage reduction among the other condition.