Medium Frequency Physical Vapor Deposited Al 2 O 3 and SiO 2 as Etch-Stop-Layers for Amorphous Indium-Gallium-Zinc-Oxide Thin-Film-Transistors

Abstract

? The Author(s) 2015. Published by ECS.In this work, we report on amorphous-Indium-Gallium-Zinc-Oxide (a-IGZO) thin-film transistor (TFT) with medium frequency physical vapor deposited (mf-PVD) etch-stop-layer (ESL). TFT with mf-PVD ESL show comparable characteristics such as fieldeffect mobility (?FE), sub-threshold slope (SS.1) and current ratio (I ON/OFF) to the conventional plasma enhanced chemical vapor deposition (PECVD) ESL based TFT, however significant differences were observed in gate bias-stress stabilities. The TFTs with mf-PVD ESL showed lower threshold-voltage (VTH) shifts compared to TFTs with PECVD ESL when stressed under a gate field of +/-1 MV/cm for duration of 104 seconds in dark and light conditions. We associate the better bias-stress stability of the mf-PVD ESL based TFT to better passivating properties and the low hydrogen content of the mf-PVD layer compared to PECVD layer.