AIO sputtered self-aligned source/drain formation technology for highly reliable oxide thin film transistor backplane

摘要

We have developed a novel fabrication process for self-aligned top-gate oxide thin film transistors (TFTs) that are suitable for high-resolution and high-speed driving in display applications. In the proposed process, the aluminum oxide (AlO) layer is sputtered onto a low-resistance oxide semiconductor film using the top-gate electrode as a mask to allow the low-resistance oxide semiconductor region to be selectively maintained as a source/drain region. Because the AlO layer that is formed by the sputtering method offers high barrier performance against impurity diffusion, both high uniformity and high reliability of the oxide TFT are realized. In addition, the developed technology can easily be expanded to enable large substrate fabrication with high productivity. A 12-in full high-definition organic light-emitting diode (OLED) display that was driven by the proposed AlO-barriered self-aligned top-gate TFT backplane was shown to provide a solution that was applicable to OLED displays. The technology developed in this work is useful for manufacturing of oxide TFT backplanes for OLED displays, which are required to have both high uniformity and high reliability.