Improving the electrical properties and stability of amorphous indium gallium zinc oxide thin-film transistors through ozone treatment

Abstract

The effect of ozone (O₃) treatment on amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) was investigated. The study utilized O₃ exposure durations ranging from 60 to 600 s, with a concentration maintained at 100 g/m³. The results indicated that a-IGZO TFTs subjected to O₃ treatment for 600 s exhibited enhanced electrical characteristics in comparison to their untreated counterparts. Specifically, there was an increase in saturation mobility (µ_sat) from 4.54 to 4.85 cm²/Vs, a decrease in subthreshold swing (S.S) from 0.41 to 0.33 V/decade, and an improvement in the on/off current ratio (I_on/off) from 1.23 × 10⁶ to 2.54 × 10⁷. Furthermore, the O₃-treated a-IGZO TFTs demonstrated greater stability in threshold voltage (V_th) shifts when subjected to humidity and negative bias illumination stability (NBIS) conditions. Notably, the Vth shift for the a-IGZO TFT treated with O₃ for 600 s remained relatively stable (ΔV_th <  – 0.3 V) under NBIS conditions over 3 h. These findings suggest that the 600-s O₃ treatment highly effective in reducing oxygen vacancy (V_O) defects within the a-IGZO channel.