The turnaround phenomenon of threshold voltage shifts is investigated in thin film transistors (TFTs) with different defect densities of hydrogenated amorphous silicon (a-Si:H) films and compositions of SiNx. It was found that TFTs with high-defect-density a-Si:H films and N-rich SiNx gate exhibit the turnaround phenomenon while TFTs with other conditions of a-Si:H and SiNx films do not. Results reveal that the turnaround phenomenon is greatly influenced by charge traps in SiNx and state creation in the a-Si:H layer. When state creation is dominant at low bias stress, the turnaround phenomenon occurs. In contrast, if charge trapping is dominant at low bias stress, the turnaround phenomenon does not occur.
|Number of pages||4|
|Journal||Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers|
|State||Published - 1 Oct 2000|