Band offsets of high dielectric constant gate oxides on silicon

High dielectric constant oxides will soon be needed to replace silicon dioxide as the gate dielectric material in complementary metal oxide semiconductor technology. The oxides must have band offsets with silicon of over 1 eV for both electrons and holes in order to have low leakage currents. We have calculated the band offsets for many candidate oxides using the method of charge neutrality levels. Ta2O5 and SrTiO3 have small or vanishing conduction band offsets on Si. La2O3, Y2O3, Gd2O3, ZrO2, HfO2, Al2O3 and silicates like ZrSiO4 have offsets over 1.4 eV for both electrons and holes, making them better gate dielectrics. Zirconates are better than titanates as they have wider gaps. (C) 2002 Elsevier Science Ltd. All rights reserved.