The impact of gate dielectric materials on the light-induced bias instability in Hf-In-Zn-O thin film transistor

This study examined the effect of gate dielectric materials on the light-induced bias instability of Hf-In-Zn-O (HIZO) transistor. The HfO(x) and SiN(x) gated devices suffered from a huge negative threshold voltage (V(th)) shift (> 11 V) during the application of negative-bias-thermal illumination stress for 3 h. In contrast, the HIZO transistor exhibited much better stability (< 2.0 V) in terms of V(th) movement under identical stress conditions. Based on the experimental results, we propose a plausible degradation model for the trapping of the photocreated hole carrier either at the channel/gate dielectric or dielectric bulk layer. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3513400]