Enhancing proton irradiation tolerance of a-IGZO thin-film transistors through hydrogen doping

초록

Amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) are promising candidates for next-generation electronic devices owing to high mobility, low processing temperature, and optical transparency. However, their vulnerability to high-energy proton irradiation severely limits device stability in radiation environments. This study presents a strategy for enhancing the proton irradiation tolerance of IGZO TFTs through hydrogen doping. Hydrogen was introduced into IGZO films by post-annealing in a 5% H2/95% Ar atmosphere and quantified by elastic recoil detection (ERD) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). Upon 5 MeV proton irradiation at a dose of 1013 cm-2, the hydrogen-doped IGZO TFTs exhibited excellent radiation stability, with a threshold voltage shift of only -0.5 V. Depth-profiled X-ray photoelectron spectroscopy (XPS) and thermal desorption spectroscopy (TDS) revealed that hydrogen doping suppresses the formation of oxygen vacancies and promotes the conversion of O-H to M-H bonds after proton irradiation, relative to undoped devices. These results suggest a dual mechanism: hydrogen passivates oxygen vacancies through site occupation, followed by M-H bond formation, and compensates for irradiation-induced excess carriers via conversion of O-H bonds to M-H bonds. This simple hydrogen annealing approach provides a practical and effective route to highly reliable, radiation-hard oxide semiconductor devices.

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