Investigating electronic and chemical properties of HfO2/ GeOxNy/Ge gate stacks: High-resolution photoelectron spectroscopy using synchrotron radiation

We implemented high-resolution photoelectron spectroscopy using synchrotron radiation (160 eV photon energy) to investigate the electronics and chemistry at the interfaces of HfO2 (1 nm)/GeOxNy (0.6 nm)/Ge gate stacks. Ge3d core-level spectra show the formation of Hf-germanate at the bottom Ge oxide-high kappa interface. Valence-band spectra highlight the presence of electronic N2p states in the Ge oxide band gap. The GeON/Ge valence band offset is determined as 1 eV{plus minus}0.2 eV.