Characterization of sputtered TiO2 gate dielectric on aluminum oxynitride passivated p-GaAs

Abstract

Structural and electrical characteristics of sputtered Ti O2 gate dielectric on p-GaAs substrates have been investigated. It has been demonstrated that the introduction of thin aluminum oxynitride (AlON) layer between Ti O2 and p-GaAs improves the interface quality. X-ray photoelectron spectroscopy and transmission electron microscopy results show that the AlON layer effectively suppresses the interfacial oxide formation during thermal treatment. The effective dielectric constant value is 1.5 times higher for the Ti O2 AlON gate stack compared to directly deposited Ti O2 on p-GaAs substrates, with a comparable interface state density. The capacitance-voltage (C-V), current-voltage (I-V) characteristics, and charge trapping behavior of the Ti O2 AlON gate stack under constant voltage stressing exhibit an excellent interface quality and high dielectric reliability, making the films suitable for GaAs based complementary metal-oxide-semiconductor technology. © 2008 American Institute of Physics.