Proof of Ge-interfacing Concepts for Metal/High-k/Ge CMOS - Ge-intimate Material Selection and Interface Conscious Process Flow

GeO₂/Ge and high-k(LaYO₃)/Ge interfaces have been significantly improved by suppressing GeO desorption and treating Ge surface with radical nitrogen. With the Ge- intimate material selection and interface conscious process flow, we have achieved that the peak hole mobility of PtGe source/drain p-MOSFET is about 370 cm²/Vsec in FUSI/GeO₂/Ge. Furthermore, metal/n-Ge ohmic characteristic has been achieved by inserting ultra-thin GeO_x layer between metal and Ge, which enables us to operate metal source/drain Ge n-MOSFETs for the first time.