Stabilization of Characteristics by Hydrogen Plasma Treatment for Top-gate Thin-film Transistor Using High-mobility Oxide Semiconductor, a-IGZTO

摘要

Top-gate thin film transistors (TFTs) using a high mobility oxide semiconductor, amorphous In-Ga-Zn-Sn-O (a-IGZTO), are attracting much attention in the field of flat panel displays. Here, the effectiveness of hydrogen plasma treatment for the formation process of low electrical resistance source/drain has been clarified. The hydrogen plasma treatment has reduced the sheet resistance of an a-IGZTO film, and this low resistance state has demonstrated high stability under heat treatment. An X-ray photoelectron spectroscopy confirmed the OH group's existence after argon plasma irradiation, suggesting that a-IGZTO has been physically sputtered. Meanwhile, it has been shown that hydrogen plasma irradiation causes the a-IGZTO to be reduced by hydrogen radicals, the reduction reaction producing metallic components. This reduction reaction is considered to have made the top-gate type TFT treated by hydrogen plasma more stable under heat treatment.