5‐2: Enhanced Bending Endurance with Transverse Tensile Strain and 4‐Terminal Double Gate LTPS TFTs for flexible AMOLED

Abstract

This letter investigates the degradation behavior of p‐channel LTPS TFTs on PI substrate under the static bending stress. During 1hr bend, the threshold voltage shifts positively and the subthreshold slope increases slightly. In transverse compressive strain, the field effect mobility increases abruptly with the decrease of the effective channel length and the off state leakage current. This is attributed to the generation of the strain‐induced GI defects near the source and drain terminals, resulting in the trapping of electrons and a shrinkage of the effective channel length and the H passivation of the strained Si bonds in the channel. By inserting the bottom metal layer to block the H diffusion from PI substrate, the controllable normal NBTI behavior is observed in a strained LTPS TFT on PI. These transverse tensile strained and 4‐termianl double gate LTPS TFTs on PI shows as a stable switching TFTs on PI for the flexible system‐on‐panel display.

43‐3: AMOLED display Sandy Mura study and improvement

“…Most of the papers report on the stability of LTPS TFT are NBTS (3)(4)(5), of which H is the key influencing factor. In fact, H is still the key influence factor of the positive bias status, so it is beneficial for Sandy Mura to select a appropriate CVD film forming condition.…”

As-Grown Crystalline InGaZnO by Spray Pyrolysis on a Flexible Substrate for a Thin-Film Transistor with Excellent Stability

“…Additionally, the method involving high-temperature annealing (>500 °C) to obtain c-IGZO TFTs is not applicable to commercial flexible display applications. Current foldable AMOLED displays with low-temperature poly-Si (LTPS) TFTs on polyimide (PI) substrates typically use process temperatures up to 470 °C for the curing of PI, dehydrogenation, and activation of dopants. − Therefore, in order to develop a high-mobility crystalline MOS TFT as a replacement for LTPS TFT, it is essential to have a process temperature lower than 470 °C, including the crystallization process.…”