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

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.