Low Energy Electron Beam Activated IGZO-based Thin Film Transistor

Abstract

The effect of electron beam irradiation (EBI) on Indium-Gallium-Zinc-oxide (IGZO)-based thin film transistor (TFT) is investigated. The TFT is formed to bottom gate structure on highly doped Si wafer for evaluating EBI effect. Before EBI treatment on IGZO based TFT, the electron density of EBI is measured by cut off probe. At an RF power of 150 W, the electron density varies from 4.04 × 108 to 1.59 × 109 cm−3 with EBI DC voltage from 50 to 1500 V. The TFT is treated by various kinds of EBI DC voltages with induced time from 0 to 180 s in a gas ambient (Ar/O2 = 10/0.3 sccm) at 100 °C. The maximum field-effect mobility (μEF)isabout 18 cm2/V-sec which is obtained as the sample annealed after EBI treatment. In addition, EBI treatment creates amorphous states into the IGZO channel which is interactively found by high resolution transmission-electron-microscopy characteristics. EBI treatment is applied to the bottom gate of IGZO based TFT on poly-imide (PI) film. After channel activation, the μEF is increased from 3.9 to 27.2 cm2/V-sec. From this study, it is anticipated that EBI will be a promising annealing method for fabricating flexible IGZO-based TFT.