Electrical characteristics of amorphous indium-tin-gallium-zinc-oxide TFTs under positive gate bias stress

Abstract

In this Letter, the authors investigate the electrical characteristics of amorphous indium-tin-gallium-zinc-oxide (a-ITGZO) thin-film transistors (TFTs) under positive gate bias stress (PBS). An as-prepared a-ITGZO TFT exhibits a mobility of 26.05 cm2/V s, subthreshold swing of 183 mV, threshold voltage of -0.33 V, and on/off ratio of 1.34 × 108. These electrical characteristics deteriorate upon the application of PBS. The proposed experiments and simulations reveal that this deterioration can be attributed to the increase in the density of acceptor-like conduction band-tail states and donor-like Gaussian states within the bandgap of the a-ITGZO channel material.