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

摘要

We investigated the effect of the high-k TiO_x (k～40) gate dielectric on the mobility (μ_(FE)) of indium-gallium-zinc oxide (IGZO) transistors. As the thickness of the TiO_x layer at the interface of the IGZO channel and SiN_x gate dielectric layer increased from 2 to 8 nm, the μ_(FE) value was monotonously reduced from 9.9 to 1.8 cm~2/V s. The degradation of the mobility was attributed to the Coulomb scattering mechanism rather than the phonon scattering mechanism of the high-k TiO_x layer based on the behavior of the temperature-dependent mobilities for all of the IGZO transistors.