TFT Backplane and Issues for OLED

The mobile display applications demand a high resolution as well as a high display image quality for which current active matrix organic light emitting diode (AMOLED) manufactures have been using low-temperature polycrystalline silicon (LTPS) thin-film transistor (TFT) backplane solutions. For large size TV application, oxide semiconductor (OS) TFT backplanes are being used. For mobile AMOLED display applications, excimer laser annealing (ELA) LTPS TFT backplane technology is used primarily in high-volume manufacturing Since the amorphous nature of the OS TFT leads to better short-range uniformity compared to laser crystallized poly-Si TFTs combined with the scalability of amorphous silicon (a-Si) TFTs, OS TFT backplane technologies have been adopted for TV applications. Liquid crystal display (LCD) TV panels use a-Si TFT backplanes whose manufacturing process is well established and low cost. OS TFT backplane has an extremely low leakage current. For OS TFT backplanes, the long-range uniformity, run-to-run reproducibility, and long-term TFT stability need to be improved.