Band offsets of high K gate oxides on high mobility semiconductors

Abstract

High mobility semiconductors such as Ge and III–V compounds will be used in future field effect transistors, with the appropriate gate dielectric. The dielectrics must have band offsets over 1 eV to inhibit leakage. The band offsets of various gate dielectrics including HfO 2, Al 2O 3, Gd 2O 3, Si 3N 4 and SiO 2 on III–V semiconductors such as GaAs, InAs, GaSb and GaN have been calculated using the method of charge neutrality levels. Generally, the conduction band offsets are found to be over 1 eV, so they should inhibit leakage for these dielectrics. There is reasonable agreement to experiment where it exists, although the GaAs:SrTiO 3 case is even worse in experiment.