Highly Stable Oxide Thin-Film Transistor-Based Complementary Logic Circuits under X-ray Irradiation

A radiation-hard oxide-thin-film transistor (TFT)-based complementary metal–oxide–semiconductor (CMOS) logic circuit composed of p-type tin oxide (SnOX) and n-type indium gallium zinc oxide (IGZO) thin-film transistors (TFTs) was proposed. The chemical states and crystalline structure of oxide thin films and their surface morphologies were analyzed as a function of the X-ray irradiation dose, exhibiting excellent radiation stability and durability for both oxide thin films under X-ray irradiation. After X-ray irradiation at a very high dose, a slight change in the chemical states was observed in both thin films, that is, an increase in the oxygen vacancies and tin dioxide components in the SnOX thin films and in the oxygen vacancy components in the IGZO thin films. The change in the chemical states observed in both thin films after X-ray irradiation explained the slight X-ray-induced negative shift of the transfer curves for both oxide TFTs. The fabricated CMOS inverter exhibited typical voltage transfer characteristics and a maximum gain of ∼33.4 V/V at a supply voltage of 10 V, which were well sustained after X-ray irradiation, even at a high dose of 100 Gy. In this study, we show that oxide-TFT-based CMOS logic circuits can potentially be used to demonstrate high-performance and radiation-robust large-area electronic systems operating in harsh X-ray environments.