Band offsets of Er2O3 films grown on Ge substrates by X-ray photoelectron spectroscopy

The band alignments of high-k Er2O3 films grown on Ge substrates by molecular beam epitaxy are determined by X-ray photoelectron spectroscopy. The valenceband and the conduction-band offsets of Er2O3 to Ge are found to be 3.16 ± 0.02 and 2.13 ± 0.02 eV, respectively. The energy gap of Er2O3 is 5.96 ± 0.02 eV as determined by the optical spectrophotometry. From the band offset viewpoint, the above results indicate that Er2O3 could be a promising candidate for high-k gate dielectrics on Ge substrate. (orig.)