Band offsets of high K gate oxides on III-V semiconductors

Abstract

III-V semiconductors have high mobility and will be used in 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 Hf O 2 , Al 2 O 3 , Gd 2 O 3 , Si 3 N 4 , and Si O 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. On the other hand, Sr Ti O 3 has minimal conduction band offset. The valence band offsets are also reasonably large, except for Si nitride on GaN and Sc 2 O 3 on GaN which are 0.6 – 0.8 eV . There is reasonable agreement with experiment where it exists, although the Ga As : Sr Ti O 3 case is even worse in experiment.