Post deposition annealing studies of lanthanum aluminate and ceria high-k dielectrics on germanium

Germanium MOS transistors with high-k gates are good alternatives for the replacement of SiO2 in order to improve the performance of modern devices. Especially rare-earth oxides on germanium deposited by molecular beam deposition (MBD) have shown improved electrical properties compared to previous used HfO2 with a germanium oxynitride (GeON) interfacial layer. In this work we report on the influence of ex situ post-annealing treatment with forming gas on the electrical characteristics of LaAlO3/Al2O3/nGe and CeO2/nGe MIS capacitors. We have observed an improvement of the electrical characteristics after forming gas anneal (FGA) for LaAlO3/Al2O3/nGe in contrast to CeO2/nGe which shows no clear trend regarding the influence of FGA.