9‐1: Invited/Distinguished Paper: Flexible TFT Backplane Development for Extremely Small Bending Radius with Organic ILD and Island TFT Structure

Abstract

A new flexible low‐temperature polycrystalline silicon thin film transistors (LTPS TFTs) backplane on PI substrate with organic dielectric layer and low‐stress structure of island TFT is proposed. This new extremely low stress backplane is able to withstand 20,000 inward bending cycles at a bending radius of 1mm without any noticeable TFT degradation. After 200,000 bending inward cycles at bending radius of 1 mm, the stability test results show that the change of on‐current is 10.07% for hot carrier instability (HCI) test, the change of threshold voltage ‐0.31V for negative bias thermal instability (NBTI) test, the change of threshold voltage ‐0.24V for hysteresis test, and the breakdown voltage of gate insulator 7.73MV/cm, respectively. The AMOLED display panel manufacured with organic ILD does not show any visible degradation of panel image just after 200K rolling at rolling radius of 4mm or 200K folding at folding radius of 1mm.