High mobility Ge pMOSFETs with 0.7 nm ultrathin EOT using HfO2/Al2O3/GeOx/Ge gate stacks fabricated by plasma post oxidation

Abstract

HfO₂/Al₂O₃/GeO_x/Ge gate stacks were fabricated by applying the plasma post oxidation to HfO₂/Al₂O₃/Ge structures. These Ge gate stack are shown to simultaneously realize both ultrathin EOT of ~0.7 nm and low D_it of 10¹¹ cm^-2eV^-1 order. The superior operation of (100) Ge pMOSFETs with these gate stacks has been demonstrated with record high hole mobility of 596 cm²/Vs under ~0.8 nm EOT among the Ge pMOSFETs reported so far.