Effects of post-deposition plasma treatments on stability of amorphous InGaZnOx thin-film transistors prepared with plasma-assisted reactive magnetron sputtering

Abstract

Effects of post-deposition plasma treatments on the stability of amorphous InGaZnOx thin-film transistors (TFTs) prepared with plasma-assisted reactive magnetron sputtering were investigated. The temporal evolution in the electrical characteristics of as-deposited IGZO TFT and post plasma treated IGZO TFT that passed over 400 d after fabrication and were kept under 40% humidity at room temperature were measured, resulting in which no change in the electrical characteristics of post plasma treated IGZO TFT with mobility of 40 cm2 V−1 s−1 were observed. Positive-current-bias instability in post plasma treated IGZO TFTs was examined together with as-deposited IGZO TFTs. The results indicated that the stabilities of electrical characteristics caused by the positive bias stress is primarily attributed to defects in the bulk a-IGZO region for as-deposited IGZO TFTs. The stabilities of electrical characteristics in post plasma treated IGZO TFTs were considerably improved compared to that of as-deposited IGZO TFTs. From these results, it was shown that the post plasma treatment is considered to be effective for improving the stability of IGZO TFTs as well as conventional thermal annealing.