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 (Y
2
O
3
-doped GeO
2
IL). Based on the understanding of Y
2
O
3
-doped GeO
2
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.