Suppressing Hydrogen-related Trap States in indium-gallium-zinc oxide thin-film transistors for High-Mobility and Low-Power Oxide Electronics

Abstract

Controlling defect states and impurity incorporation in oxide semiconductors is crucial for advancing high-performance thin-film transistors. Here we show that hydrogen impurities act predominantly as deep-level electron traps, critically limiting both performance and reliability. Using density functional theory calculations supported by experimental analysis, we demonstrate that suppressing hydrogen incorporation markedly improves device characteristics. Indium-gallium-zinc oxide transistors fabricated under hydrogen-controlled conditions exhibit enhanced bias stability and, with an aluminum electron-injection layer, achieve a high field-effect mobility of about 120 cm(2)/V.s, nearly twice that of devices processed in hydrogen-rich environments. These devices also support high-speed switching up to 1 MHz. When integrated with a negative capacitance structure, they exhibit subthreshold swing values as low as 39 mV/dec, surpassing the thermionic limit. Inverter circuits with hydrogen-suppressed IGZO TFTs with an aluminum electron-injection layer deliver a gain of similar to 50, far exceeding the similar to 10 of conventional counterparts. These findings highlight hydrogen control as a key enabler of low-power, high-speed oxide electronics.