Band alignment of yttrium oxide on various relaxed and strained semiconductor substrates

In this work, we report on the band offsets of yttrium oxide (Y2O3) on various relaxed and strained semiconductor substrates, such as silicon (Si), germanium (Ge), and silicon germanium (SiGe). By using the example of Y2O3/Si, important experimental aspects in using photoemission to determine band offsets are discussed. We then discuss the various values of band offsets of Y2O3 on the different substrates that we obtained by using x-ray photoelectron spectroscopy. Finally, we show that presputtering 3 A of metallic Y [equivalent to 1 ML (monolayer) coverage] before the deposition of Y2O3 affects the band lineup by reducing the resultant valence band offsets. We explain the observed band offsets by using an interfacial layer model. (C) 2008 American Institute of Physics.