Reliability of low-temperature polysilicon thin-film transistors for flexible electronics application

Electrical reliability of p-channel low-temperature polysilicon (LTPS) thin-film transistors (TFTs) fabricated from conventional or flexible display technology are compared under positive or negative gate bias stress (PBS/NBS). Conventional TFTs have better initial characteristic than flexible TFTs, and better stability under PBS, while flexible TFTs have better stability under NBS. Mechanical reliability of flexible TFTs is investigated under repetitive bending and stretchy stress. It is found that their degradation behaviors are similar, where TFTs threshold voltage shifts positively without much change in the subthreshold region. The degradation is attributed to mechanical stress induced negative charge trapping at the channel/gate oxide interface.