Chang Dong Kim

Reliable Bottom Gate Amorphous Indium-Gallium-Zinc Oxide Thin-Film Transistors with TiOx Passivation Layer

Titanium oxide (TiO x ) passivation layer was employed and optimized to stabilize the performance of the bottom gate amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs). A molybdenum/titanium (Mo/Ti) source-drain electrode was deposited on an a-IGZO layer, and the TiO, passivation layer was formed by oxidizing the Ti layer using oxygen plasma after etching the Mo layer. By increasing the oxygen plasma treatment time, the subthreshold slope and leakage current of the a-IGZO TFTs were improved to 0.78 V decade -1 and 0.3 pA, respectively, and the degradation of the TFT performance was not observed, even after thermal treatment at 280°C for 1 h.

9.3: Control of Threshold Voltage in Back Channel Etch Type Amorphous Indium Gallium Zinc Oxide Thin Film Transistors

Tuning the process pressure at the deposition of the passivation layers has been suggested in the way of controlling the threshold voltage of a-IGZO TFTs, making it possible to employ gate driver integration. It has showed that Vth linearly changes with the pressure ΔVth/ΔPressure∼3.5V/100Pa. A 3.2 inch WVGA AMLCD with integrated gate driver circuits were successfully demonstrated using the enhancement mode BCE type bottom gate a-IGZO TFTs.

Full color flexible displays on thin metal foil with reduced bending radius

We have developed Full color flexible AM-OLED and AM-EPD displays using a thin metal foil, allowing them to recover their original shape after being bent as well as to produce vivid color images. The key development technologies including a-Si TFT fabrication on thin stainless steel foil and integrated driver electronics in the display panel are described along with improved display performance in a curvature of 5cm bending radius.

70.2: Distinguished Paper: Flexible Display Technology for a Mass Production using the Improved Etching Technology

Flexible displays have attracted much attention as a future display due to highly rugged, lightweight, and extremely low power consumption. We have developed the flexible process technology for a mass production using the improved etching technology. F-DIET (Flexible Display using Improved Etching Technology) technology enables us to make a flexible display in standard AMLCD factories and to stably manufacture of flexible AMEPD and AMOLED.