Radiation-Tolerant Amorphous Indium-Zinc-Tin-Oxide Thin-Film Transistors

Abstract

Metal oxide thin-film transistors (MOTFTs) have been widely utilized in various electronic devices such as display backplanes, radiation detectors, and aerospace applications. As these electronics are increasingly deployed in harsh space and heavy radiation environments, the demand for semiconductor materials capable of maintaining electrical and structural stability has intensified. However, the limited understanding of how X-ray irradiation influences metal oxide semiconductor behavior has hindered their reliable use in practical heavy-radiation environments. In this study, we investigate the change of the electrical characteristics of metal oxide semiconductors such as amorphous indium gallium zinc oxide (a-IGZO), zinc tin oxide (a-ZTO), and indium zinc tin oxide (a-IZTO) under X-ray irradiation. The extracted threshold voltage shifts reveal a substantial difference among the three metal oxide semiconductors, with a-IGZO exhibiting a large shift of Delta Vth <= 16 V and a-ZTO showing a moderate shift of Delta Vth <= 7.1 V, while a-IZTO demonstrates significantly improved irradiation tolerance with a minimal shift of Delta Vth <= 2.3 V even when the corresponding TFTs are X-ray irradiated up to 7 kGy. The distinct threshold voltage shifts induced under X-ray irradiation are primarily driven by excessive oxygen vacancy formation and radiation induced ionization. This study demonstrates that metal oxide semiconductors have significant potential as radiation hardness large area electronic devices for medical and aerospace applications.