Hafnium-Indium-Zinc oxide thin film transistors using HfO2 as gate dielectric, with both layers deposited by RF sputtering

Abstract

The electrical performance of RF magnetron sputtered Hafnium-Indium-Zinc-Oxide-based thin film transistors (HIZO TFTs) is compared using two different gate dielectrics: a) RF sputtered HfO₂ and b) thermally grown SiO₂. For HfO₂ devices, output characteristics showed higher drain-currents capabilities with a reduction of the TFT operation voltage range from 0-15 V, when using SiO₂, to 0-8 V. The HfO₂ dielectric constant was around 15, measured at 1 kHz. Vt was less than 2 V for HfO₂ devices and around 5 V for SiO₂ devices.