Germanium MOSFETs with CeO2/HfO2/TiN gate stacks

Long-channel Ge pMOSFETs and nMOSFETs were fabricated with high-kappa CeO2/HfO2/TiN gate stacks. CeO2 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 similar to 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.