(Invited) Highly Stable Self-Aligned Top-Gate Indium Gallium Zinc Oxide Thin-Film Transistors for High-Resolution OLED TV and Mobile Displays

Highly stable self-aligned coplanar top-gate InGaZnO (IGZO) thin-film transistors (TFTs) with excellent threshold voltage (Vth) uniformity are developed by optimizing gate insulator film properties and controlling oxygen/hydrogen diffusion into IGZO channel. The TFTs do not show notable negative Vth shift and Vth non-uniformity from channel length 10 µm down to 3 µm. The TFTs also show no notable Vth shift during a humidity test in a chamber at 85°C/85% after deposition of passivation layers or even after 1-µm-thick thin-film encapsulation (TFE) SiNx layer on the top of the passivation layer due to the high quality/low hydrogen 2nd SiNx passivation layer deposited on the top of 1st SiOx passivation layer.