The effects of a HfO₂ buffer layer on Al₂O₃‐passivated indium‐gallium‐zinc‐oxide thin film transistors

Abstract

Abstract In this study, the effects of a HfO 2 buffer layer between an Al 2 O 3 passivation layer and an indium‐gallium‐zinc‐oxide (IGZO) thin film transistor (TFT) were investigated to enhance the environmental stability and electrical properties of the IGZO TFT. When applying the HfO 2 buffer layer, the formation of HfAl x O y at the Al 2 O 3 /HfO 2 interface reduces the water vapor transmission rate (WVTR) due to densification of the passivation layer. Consequently, by adding the HfO 2 buffer layer, WVTR of the TFT was highly improved; moreover, changes in the electrical characteristics can be prevented compared to both the non‐passivated and Al 2 O 3 ‐passivated TFTs. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)