Germanium MOSFETs with CeO2/HfO2/TiN gate stacks

Long-channel Ge pMOSFETs and nMOSFETs were fabricated with high-k CeO 2 /HfO 2 /TiN gate stacks. CeO 2 was found to provide effective passivation of the Ge surface, with low diode surface leakage currents. The pMOSFETs showed a large I ON /I OFF ratio of 10 6 , a subthreshold slope of 107 mV/dec, and a peak mobility of approximately 90 cm 2 /V ·s at 0.25 MV/cm. The nMOSFET performance was compromised by poor junction formation and demonstrated a peak mobility of only ∼3 cm 2 /V ·s but did show an encouraging I ON /I OFF ratio of 10 5 and a subthreshold slope of 85 mV/dec.