Grain boundary trap passivation in polysilicon thin film transistor investigated by low frequency noise

Electrical characterisation is made on low temperature unhydrogenated and h ydrogenated in in-situ doped polysilicon thin him transistors (TFTs). The l ow frequency noise measurements are analysed and related to the static perf ormances of these high mobility TFTs, accounting to the grain boundary pote ntial barrier lowering. The results suggest the existence of two types of e xcedentary noise sources, probably located respectively, at the SiO2/Si int erface and in the grain boundary depleted zone. The hydrogenation, which al lows the improvement of electrical static performances, passivates charge t raps at the SiO2/Si and grain boundary interfaces and acts in reducing both noise contributions. (C) 2001 Elsevier Science B.V. All rights reserved.