Impact of interfacial layer control using Gd2 O3 in Hf O2 gate dielectric on GaAs

Abstract

Structural and electrical properties of Hf O2 and Hf O2 Gd2 O3 gate stacks on p-GaAs substrates have been investigated. It has been demonstrated that the presence of thin layer of Gd2 O3 between Hf O2 and GaAs improves metal-oxide-semiconductor device characteristics such as interface state density, accumulation capacitance, frequency dispersion, and leakage current. It is also found that Hf O2 Gd2 O3 stack can reduce the interfacial GaAs-oxide formation, thus reduce the outdiffusion of elemental Ga and As during post-thermal annealing process. Such suppression of outdiffusion significantly improves the electrical properties of the dielectric stacks. © 2007 American Institute of Physics.