A Novel Multi-Channel Poly-Si TFT Improving Hydrogen Passivation

Abstract

ABSTARCTWe have fabricated a new multi-channel polycrystalline silicon thin film transistor (ploy-Si TFT), of which structure may be more effectively hydrogenated than conventional multi-channel poly-Si TFT. The new multi-channel TFT has stripe-cuts in gate electrode so that more hydrogen radicals penetrate into the gate oxide and passivate the active poly-Si layer. After 90 min. hydrogenation of the new device, the electrical characteristics such as threshold voltage and field effect mobility are improved more than those of conventional device.The new multi-channel poly-Si TFT, which receives more hydrogen radicals thorough gate oxide than the conventional multi-channel TFT, can be hydrogenated effectively in long channel devices. Besides the improvement of the device characteristics, our experimental results show that the dominant hydrogenation path is the diffusion though the gate oxide.

Silicon device processing in H-ambients: H-diffusion mechanisms and influence on electronic properties

“…10,11 Concomitantly, hydrogenation is used in Si solar cells 12,13 and in thin-film transistor (TFT) applications to passivate grain boundaries in poly-Si. 14,15 Hydrogen can also interact with impurities in Si. The nature of such interactions depends on the type of impurities.…”