Impact of La 2 O 3 Thickness on HfO 2 /La 2 O 3 /Ge capacitors and p-channel MOSFETs

In this study we report on HfO 2 /La 2 O 3 /Ge gate stacks grown by MBE with varying thicknesses of La 2 O 3 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 La 2 O 3 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.