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We demonstrated a Cu gate hydrogenated amorphous silicon thin-film transistor (TFT) with buffer layers. We introduced an AlN/Cu/Al 2 O 3 multilayer for a gate of an a-Si : H TFT. The Al 2 O 3 improves the adhesion to glass substrate and AlN protect the Cu diffusion to the TFT and plasma damage to Cu during plasma enhanced chemical vapor deposition of silicon-nitride. An a-Si : H TFT with a Cu gate exhibited a field effect mobility of 1.18 cm 2 /Vs, a gate voltage swing of 0.87 V/dec., and a threshold voltage of 3.5 V.Index Terms-AMLCD, low resistivity, metal, thin-film transistor (TFT).

We demonstrated a silver gate hydrogenated amorphous silicon thin film transistor(a-Si:H TFT) using thin buffer layers of alumina(Al 2 O 3 ) and aluminum-nitride(AlN). An Al 2 O 3 layer on glass substrate was deposited so as to increase adhesion between APC(> 98 wt% silver) and glass substate. An AlN layer on APC was deposited to prevent it from plasma damage during siliconnitride(SiNx) deposition. The Ag gate a-Si:H TFT with these buffer layers exhibited a field-effect mobility of 1.15 cm 2 /Vs, a gate voltage swing of 0.86 V/dec. and a threshold voltage of 2.5 V.

A novel LTPS method called MICC (metal-induced crystallization using a cap) is introduced. The role of cap layer on a-Si is the control of the nickel concentration for inducing crystallization as well as the passivation of the surface during thermal process for crystallization. Circular grain growth can be seen, due to lateral grain growth from a seed. Polycrystalline silicon with large grain and smooth surface can be achieved by MICC. We fabricated a AMLCD with high aperture ratio of 80 % using silicon-based spin-on low-K dielectrics as a planarization layer.

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