Highly Stable Amorphous Metal Oxide Thin-Film Transistors for In Situ X-ray Tolerant Electronics

Abstract

Thin-film transistors based on metal oxide semiconductors are essential for many unconventional electronic devices, such as flat panel displays, image sensors, medical detectors, and aerospace applications. However, the lack of a systemic understanding of the effects of X-ray irradiation on the device often limits their use in harsh space and heavy radiation environments. Here, we investigate the effects of X-ray irradiation on metal oxide thin-film transistors based on amorphous indium gallium zinc oxide (a-IGZO) and amorphous zinc tin oxide (a-ZTO) semiconductors. Under increasing doses of X-ray irradiation (1-7 kGy), a-IGZO TFTs exhibit a substantial negative shift in threshold voltage (Delta V th <= 16 V), indicating severe degradation of the switching behavior. The underlying mechanisms responsible for this radiation-induced damage in a-IGZO TFTs are attributed to the generation, ionization, and compensation of oxygen vacancies, which disrupted the device stability. In contrast, a-ZTO TFTs display markedly superior resilience (Delta V th <= 7.26 V), maintaining a stable electrical performance under similar X-ray irradiation conditions. In addition, both ex situ and in situ experimental results exhibit consistent trends in terms of the degradation and stability of the devices under X-ray irradiation, further validating the reliability of the a-ZTO TFTs in real-time radiation hardness operational environments. The proposed mechanisms elucidating the difference in radiation tolerance between a-IGZO and a-ZTO TFTs provide understanding of the stability and robustness of metal-oxide-based TFTs under extreme irradiation environments.