||In this thesis, we will investigate the degradation of the Low-Temperature-Polycrystalline-Silicon TFTs(LTPS TFTS) under the electrical stress. The devices are offer by Chi Mei Optoelectronics. The two mechanisms of the electrical stress are AC and DC stress. On the AC stress, there are some phenomena which cannot be completely explained by typical NBTI mechanism in the experiment. In addition to NBTI, we suggest that the self-heating effect might be involved, because the self-heating effect could rise channel temperature and cause the dissociation of the Si-H bonds at the poly-Si/SiO2 interface due to the Joule heating. We also compare pulse to give on the degradation difference of different place.|
On the DC stress, we show the stress drain voltage dependence of on-current and threshold voltage degradation, in which the stress gate voltage was fixed at -15V and stress time was 2154 s. The electric measurements of forward and reverse modes were employed to analyze the experimental data. The anomalous negative bias temperature instability degradation of poly-Si TFTs was investigated.