Comparative analysis of temperature thermally induced instability between Si–In–Zn–O and Ga–In–Zn–O thin film transistors

Thermally induced instability of amorphous Si–In–Zn–O (SIZO) with 1 wt.% silicon (Si) concentration and Ga–In–Zn–O (GIZO) with gallium (Ga) of 30 wt.% thin film transistors (TFTs) has been investigated, by comparing the density of states extracted from multi-frequency method. It was observed that the density of state of SIZO-TFT was lower than that of GIZO-TFT, in spite of low processing temperature of SIZO-TFT and thermally induced instability of SIZO- and GIZO-TFT was strongly related with the total trap density. We report that Si of only 1 wt.% in SIZO can improve thermal stability of threshold voltage of In–Zn–O based TFTs more effectively than Ga of 30 wt.% in GIZO.