Plasma post-oxidation for high mobility strained-Ge pFETs with aggressively scaled high-κ dielectrics

In this work, transport is explored in strained-Ge (s-Ge) p-MOSFETs with a hybrid GeOx/Al2O3/HfO2 gate stack directly on the channel with and without plasma post-oxidation (PPO). A gate-first process with ion implanted source/drains and a 625°C activation process was utilized. The gate stack is improved using PPO allowing for a demonstration of both extremely scaled CET (CET - 1.1 nm) and high mobility at high inversion charge. This demonstration suggests that this gate stack is a candidate for scaled s-Ge p-MOSFETs.