Band offsets of Er{sub 2}O{sub 3} films epitaxially grown on Si substrates

The experimental data on band alignments of high-k Er{sub 2}O{sub 3} films epitaxially grown on Si substrates by molecular beam epitaxy are reported. By using x-ray photoelectron spectroscopy, the valence and the conduction-band offsets of Er{sub 2}O{sub 3} to Si are obtained to be 3.1{+-}0.1 and 3.5{+-}0.3 eV, respectively, showing a roughly symmetrical offset at the conduction and the valence band. The energy gap of Er{sub 2}O{sub 3} is determined to be 7.6{+-}0.3 eV. From the band offset viewpoint, those obtained numbers indicate that Er{sub 2}O{sub 3} could be a promising candidate for high-k gate dielectrics.