Oxygen potential engineering of interfacial layer for deep sub-nm EOT high-k gate stacks on Ge

The interfacial layer (IL) control is a key to achieving deep sub-nm EOT gate stacks with maintaining superior interface properties. We propose the thermodynamically robust IL engineering on Ge (Y₂O₃-doped GeO₂ IL). Based on the understanding of Y₂O₃-doped GeO₂ IL, we have demonstrated 0.47-nm-thick EOT on Ge, and the highest electron mobility at high-N_s in Ge n-MOSFETs with sub-nm-thick EOT.