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

摘要

Germanium MOS transistors with high-κ gates are good alternatives for the replacement of SiO_2 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 HfO_2 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 LaAlO_3/Al_2O_3/nGe and CeO_2/nGe MIS capacitors. We have observed an improvement of the electrical characteristics after forming gas anneal (FGA) for LaAlO_3/Al_2O_3/ nGe in contrast to CeO_2/nGe which shows no clear trend regarding the influence of FGA.