Probing buried interfaces on Ge-based metal gate/high-k stacks by hard X-ray photoelectron spectroscopy

▶ A thin Si interlayer prevents the oxidation of the substrate in Ge based metal-gate/high-k stacks. ▶ Hard X-ray photoelectron spectroscopy enables a non-destructive analysis of interfaces buried several nanometers. ▶ A Hf silicate is formed at the interface between HfO2 and SiO2.