Impact of high- k TiOx dielectric on device performance of indium-gallium-zinc oxide transistors

Abstract

We investigated the effect of the high- k TiOx (k∼40) gate dielectric on the mobility (μFE) of indium-gallium-zinc oxide (IGZO) transistors. As the thickness of the TiOx layer at the interface of the IGZO channel and SiNx gate dielectric layer increased from 2 to 8 nm, the μFE value was monotonously reduced from 9.9 to 1.8 cm2 /V s. The degradation of the mobility was attributed to the Coulomb scattering mechanism rather than the phonon scattering mechanism of the high- k TiOx layer based on the behavior of the temperature-dependent mobilities for all of the IGZO transistors. © 2009 American Institute of Physics.