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.