Effects of Al2O3 surface passivation on the radiation hardness of IGTO thin films for thin-film transistor applications

Abstract

In this study, we examined the effects of aluminum oxide (Al2O3) surface passivation on the radiation damage of indium-gallium-tin oxide (IGTO) thin films and radiation hardness of IGTO thin-film transistors (TFTs). The radiation hardness of the TFTs was investigated using a 3.5-MeV proton beam at a dose of 1013 cm−2. From the obtained results, it was observed that the radiation hardness significantly improved with a decrease in the thickness of the Al2O3 passivation layer. In addition, the IGTO TFT passivated by an Al2O3 thin film prepared using sputtering exhibited a higher radiation resistance than that passivated by an Al2O3 thin film formed using the atomic layer deposition method, even when the film thickness was the same. From the thin-film analyses carried out on various Al2O3/IGTO samples before and after proton irradiation, it was observed that the thickness and deposition technique of the Al2O3 passivation layer substantially affected the concentration of oxygen vacancies and hydrogen within the IGTO thin film after proton irradiation. Overall, our results showed that the passivation layer significantly affects the radiation hardness of oxide TFTs, and that it is necessary to optimize the thickness and deposition technique of the passivation layer to obtain radiation-tolerant oxide TFTs. © 2021 Elsevier B.V.