Impact of La2O3 Thickness on HfO2/La2O3/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.