Degradation Behaviors of Trigate Nanowires Poly-Si TFTs with NH[sub 3] Plasma Passivation under Hot-Carrier Stress

Abstract

This work studies degradation behavior after hot-carrier stress of trigate polysilicon thin-film transistors (poly-Si TFTs) with nanowires. The NH 3 plasma passivation effect is also studied on the electrical characteristics after hot-carrier stress. The reliability of poly-Si TFTs with NH 3 plasma passivation outperforms that without such passivation, resulting from the effective hydrogen passivation of the grain-boundary dangling bonds, and the pileup of nitrogen at the SiO 2 /poly-Si interface. The reliability of poly-Si TFTs further improves by using nanowires structure. These findings originate from the fact that the nanowires poly-Si TFT has robust trigate control to reduce the hot-carrier effect due to declining lateral electrical field and its penetration from the drain, and its split nanowire structure has superior NH 3 plasma passivation effect. In degradation results under dc and ac stress, it reveals that the NH 3 plasma is mostly passivated on deep traps of grain boundaries rather than tail traps.