Photoelectron spectroscopy of ultrathin yttrium oxide films on Si(100)

The Y2O3/SiO2/Si(100) stack structures were prepared by the thermal decomposition of a yttrium organic complex in O-2 ambient at 350 degreesC and subsequent O-2-anneal at 500 degreesC. From the analysis of O1s energy loss spectra, the energy band gap was determined to be 6.0 +/- 0.05 eV for Y2O3 and 8.9 +/- 0.05 eV for interfacial SiO2. By deconvoluting the valence band spectra into the components, valence band offsets for Y2O3 with respect to Si(100) and interfacial SiO2 were obtained to be similar to3.3 and similar to1.3 eV, respectively, which indicates the conduction band offset of similar to1.58 eV between Y2O3 and Si(100). Total photoelectron yield spectra show an increase in the electronic defect states with post deposition O-2-anneal in the temperature range 300-700 degreesC, which is related to the formation of interfacial SiO2 layer at such low temperatures. (C) 2004 Elsevier B.V. All rights reserved.