Stability and band offsets between GaAs semiconductor and CeO2 gate dielectric

Abstract

Cerium oxide (CeO2) appears to be a promising candidate high-k dielectric material in GaAs-based metal-oxide-semiconductor field-effect transistors. The electronic properties of GaAs/CeO2 (001) heterojunctions are investigated by density functional theory. We determine the GaAs/CeO2 heterostructure from the initial adsorption of the Ga and As atoms on the CeO2 (001) surfaces. The surface formation energy indicates that oxygen or Ga atoms may replace Ce atoms at the Ce-terminated CeO2 surface, and Ce atoms may replace oxygen atoms at the O-terminated CeO2 surface. The band offsets, electronic density of states, and atomic charges are analyzed for the GaAs/CeO2 heterojunctions. The band offsets of the As-terminated GaAs/Ce-terminated CeO2 interface are suitable for the design of metal-oxide-semiconductor devices. The OCe defects induce a two-dimensional electron gas at the As-terminated GaAs/Ce-terminated CeO2 interface.