The effects of NH3 plasma passivation on polysilicon thin-film transistors

The NH ₃ plasma passivation has been performed for the first time on the polycrystalline silicon (poly-Si) thin-film transistors (TFT's). It is found that the TFT's after the NH ₃ plasma passivation achieve better device performances, including the off-current below 0.1 pA/μm and the on/off current ratio higher than 10/sup 8/, and also better hot-carrier reliability as well as thermal stability than the H ₂ -plasma devices. These improvements were attributed to not only the hydrogen passivation of the grain-boundary dangling bonds, but also the nitrogen pile-up at SiO ₂ /poly-Si interface and the strong Si-N bond formation to terminate the dangling bonds at the grain boundaries of the polysilicon films.