Hydrogen-free oxide thin-film transistor toward resolving hydrogen-associated instability

We propose and demonstrate the concept of hydrogen-free (H-free) amorphous oxide semiconductor thin-film transistors (AOS TFTs) to resolve hydrogen-associated instability of TFT. H-free SiO₂ and SiN_x films were successfully deposited by large-area inductively coupled plasma chemical vapor deposition (ICP-CVD) using hydrogen-free source gases. H-free SiO₂ and SiN_x films were applied as the gate insulator and passivation layers of the TFT, respectively. The H-free In–Ga–Zn–Sn–O (IGZTO) TFT exhibited field-effect mobility of 23.2 cm²V⁻¹ s⁻¹ and excellent stability under positive gate bias stresses for 7,200 s at stress temperatures in the range of 60–100°C.