Band offsets of wide-band-gap oxides and implications for future electronic devices

Wide-band-gap oxides such as SrTiO₃ are shown to be critical tests of theories of Schottky barrier heights based on metal-induced gap states and charge neutrality levels. This theory is reviewed and used to calculate the Schottky barrier heights and band offsets for many important high dielectric constant oxides on Pt and Si. Good agreement with experiment is found for barrier heights. The band offsets for electrons on Si are found to be small for many key oxides such as SrTiO₃ and Ta₂O₅ which limit their utility as gate oxides in future silicon field effect transistors. The calculations are extended to screen other proposed oxides such as BaZrO₃. ZrO₂, HfO₂, La₂O₃, Y₂O₃, HfSiO₄, and ZrSiO₄. Predictions are also given for barrier heights of the ferroelectric oxides Pb_1-xZr_xTiO₃ and SrBi₂Ta₂O₉ which are used in nonvolatile memories. © 2000 American Vacuum Society.