Yasuhiro Terai

69.2: Highly Reliable Oxide‐Semiconductor TFT for AM‐OLED Display

We developed highly reliable oxide semiconductor TFT for AM- OLED displays. Passivating films, source/drain metals, and the TFT structure were optimized with an eye to improving device reliability to provide a lifetime over 10 years. An 11.7-inch diagonal qHD AM-OLED display was demonstrated to provide applicable solution for a large size OLED and an ultra-high definition LCD TV mass-production.

High-mobility oxide TFT for circuit integration of AMOLEDs

Abstract— A high-mobility and high-reliability oxide thin-film transistor (TFT) that uses In-Sn-Zn-O (ITZO) as a channel material has been developed. The mobility was 30.9 cm2/V-sec and the threshold voltage shift after 20,000 sec of a bias-temperature-stress (BTS) test (with a stress condition of Vg = 15 V, Vd = 15 V, and T = 50°C) was smaller than 0.1 V. In addition, a method of obtaining a stable enhancement-type TFT, which realizes circuit integration for active-matrix organic light-emitting diode (AMOLED) displays has been developed.

Highly reliable oxide-semiconductor TFT for AMOLED displays

Abstract— The stability and reliability of oxide-semiconductor TFTs were investigated. The contact material to the oxide semiconductor affected the thermal stability of the TFT, and a molybdenum-contact source/drain showed good stability. And the passivating film and TFT structure affected the stability against bias stress and humidity stress, and dc-sputtered Al2O3 passivation and fully covered channel structure with an etching stopper or source/drain showed good reliability. Moreover, high photo-stability was confirmed by the bias-enhanced photo-irradiation stress test. An 11.7-in.-diagonal qHD AMOLED display was demonstrated to provide an applicable solution for a large-sized OLED and an ultra-high-definition LCD-TV mass production.