Effects of hydrogenation on the performance and hot-carrier endurance of polysilicon thin-film transistors

Statistical analysis was performed to investigate the performance and relia bility of hydrogenated polysilicon thin-film transistors (TFTs) in relation to the hydrogenation process. The hydrogenation was performed in pure H-2 plasma and in plasma of 4% H-2 diluted in Ar or He gas. TFTs hydrogenated i n H-2/Ar or H-2/He plasma have lower on-voltage and better uniformity compa red to the nonhydrogenated devices due to passivation of grain boundary dan gling bonds. Hot-carrier experiments demonstrate that electron trapping is the dominant mechanism at the early stages of the degradation process and g eneration of interface and grain boundary traps as the stress proceeds furt her, The overall results indicate that devices hydrogenated in plasma of H- 2/He are the most reliable in terms of uniformity and hot-carrier stress.