Novel Low Temperature SiO2 Formation Process by Oxygen and Hydrogen Radicals for Core and I/O RMG Stacks: Achieving the Ultimate NBTI Reliability with a Charge-Free IL

Abstract

Low thermal budget RMG integration is required for future CMOS architectures. We demonstrate a novel low-temperature (450°C) plasma-based SiO2 formation process by oxygen and hydrogen radicals yielding a low-defectivity, fixed charge-free interfacial layer, and outmatching conventional SiO2 formation processes, including a 900°C dry oxidation. IL thickness control is demonstrated in the range of relevance for Core Logic and I/O gate stacks, which would not be possible with conventional self-limited chemical oxidation only. The novel IL enables ultimate NBTI reliability due to suppressed hole trapping and minimized interface state generation, without requiring any post-growth treatment. A comparative analysis vs. conventional chemOx IL with various treatments sheds light on the role of SiO2 positive fixed charge (trapped protons) on hole trapping and interface state de-passivation during NBTI stress.