Impact of La₂O₃ thickness on HfO₂/La ₂O₃/Ge capacitors and p-channel MOSFETs

In this study we report on HfO2/La2O3Ge gate stacks grown by MBE with varying thicknesses of La2O3 for MOS capacitors and pMOSFETs. Negative threshold voltages, around -0.8 V, in combination with scaled devices with an EOT of 1.4 nm shows good characteristics for the La2O3 as a passivation for Ge. Also the effect of various post-metallization anneals in oxygen and forming gas is shown to improve the capacitors and MOSFETs, yielding mobility of 121 cm 2/Vs. ©2009 IEEE.