Composition Dependence of the Negative Bias Light Illumination Instability of Indium Zinc Oxide Transistors

Abstract

This study examined the effects of the indium fraction in indium zinc oxide (IZO) on the performance and stability of IZO thin film transistors (TFTs). The field-effect mobility and sub-threshold swing were much improved with increasing In fraction; 41.0 cm2/Vs and 0.2 V/decade, respectively, at 85 at% In, compared to 1.1 cm2/Vs and 2.4 V/decade of ZnO TFTs. In contrast, a local minimum negative bias illumination stress instability was observed near 73~77 at% In. This behavior was explained by a poly-crystalline to amorphous phase transition in IZO thin films.