Characteristics of Plasma-Fluorinated Zinc Oxide Thin-Film Transistors

Plasma-immersion doping, a technique more compatible with the processing of large-area glass substrates, is investigated as a replacement of ion implantation for incorporating fluorine in a zinc oxide thin film to improve the electrical characteristics of the corresponding thin-film transistors. Since the average energy of the ions in a plasma is lower than that of the ions used for implantation, less damage is induced in the channel of a transistor by the bombardment of the ions. Consequently, enhancement-mode transistors with a relatively high field-effect mobility of ~71 cm²/V·s, a lower drain leakage current, and improved reliability have been realized.