Oxide TFT technology
Oxide SemiconductorAn active-matrix organic light-emitting diode (AM-OLED) display has superior features such as high contrast ratio, high response speed, thin shape and light weight. Because the OLED is a current-driven device, high current flow is required for the thin film transistor (TFT) to realize high luminance. The conventional TFT technologies for the liquid crystal display (LCD) have some issues for the AM-OLED applications.
TFT performance degradation due to the high current flow is an issue for amorphous silicon (a-Si) TFT, and non-uniform TFT performance due to the crystallization process and high manufacturing cost due to the long manufacturing process steps are the issues for low temperature poly-silicon (LTPS) TFT.
Oxide TFT is a good candidate to achieve uniform and high current flow with low cost production. Metal oxide materials (i.g. In-Ga-Zn-O) have high electron mobility for the high current flow and are uniformly formed on the large substrate by conventional deposition method.
The Evolution of TFTsWe have developed a novel self-aligned top-gate TFT. To realize superior reliability, Al-reaction method is invented for the source/drain formation and alumina is applied as a passivation.
This TFT is designed to be fabricated by a simple process flow for the low cost manufacturing and to have extraordinary small parasitic capacitance for the high resolution AM-OLED display.
JOLED provides amazing image quality with the low cost, highly reliable oxide TFT technology.