Low-temperature fabrication of fully transparent IGZO thin film transistors on glass substrate

We fabricate fully transparent indium gallium zinc oxide thin film transistors (a-IGZO TFTs) on glass substrates at relatively low temperature. The sputtering process used are all carried out at room temperature, and SiO₂ PECVD (Plasma Enhanced Chemical Vapor Deposition) run at 80, which is highest temperature we use in this fabrication. And while sputtering IGZO layer we change the O₂ flux in order to study the effect of oxygen content on performance of IGZO TFT, and to find out the optimum condition for TFTs´ fabrication. We find that TFTs fabricated with flux ratio of oxygen and argon (O₂:Ar ratio) of 3:97 demonstrate the best transfer curves with highest on-to-off current ratio (I_on/off) of 1.69×10⁸ and a high on current of 2.71mA, and its output characteristic is also very good. In addition, we find that difference between on-current measured at different V_ds, 0.5V and 5V, respectively, became small while amount of O₂ increased during IGZO deposition.