Co-Optimization of the Metal Gate/High-k Stack to Achieve High-Field Mobility >90% of SiO{sub}2 Universal Mobility With an EOT= ～ 1 nm

摘要

HfO{sub}2 and HfSiON gate dielectrics with high-field electron mobility greater than 90% of the SiO{sub}2 universal mobility and equivalent oxide thickness (EOT) approaching 1 nm are successfully achieved by co-optimizing the metal gate/high-k/bottom interface stack. Besides the thickness of the high-k dielectrics, the thickness of the ALD TiN metal gate and the formation of the bottom interface also play an important role in scaling EOT and achieving high electron mobility. A phase transformation is observed for aggressively scaled HfO{sub}2 and HfSiON, which may be responsible for the high mobility and low charge trapping of the optimized HfO{sub}2 gate stack.