Circuits using uniform TFTs based on amorphous In‐Ga‐Zn‐O

Abstract

Abstract— High‐performance and excellent‐uniformity thin‐film transistors (TFTs) having bottom‐gate structures are fabricated using an amorphous indium‐gallium‐zinc‐oxide (IGZO) film and an amorphous‐silicon dioxide film as the channel layer and the gate insulator layer, respectively. All of the 94 TFTs fabricated with an area 1 cm 2 show almost identical transfer characteristics: the average saturation mobility is 14.6 cm 2 /(V‐sec) with a small standard deviation of 0.11 cm 2 /(V‐sec). A five‐stage ring‐oscillator composed of these TFTs operates at 410 kHz at an input voltage of 18 V. Pixel‐driving circuits based on these TFTs are also fabricated with organic light‐emitting diodes (OLED) which are monolithically integrated on the same substrate. It is demonstrated that light emission from the OLED cells can be switched and modulated by a 120‐Hz ac signal input. Amorphous‐IGZO‐based TFTs are prominent candidates for building blocks of large‐area OLED‐display electronics.