A high-performance polycrystalline silicon thin film transistor with a silicon nitride gate insulator

We have fabricated a high performance polycrystalline silicon (poly-Si) thin film transistor (TFT) with a silicon-nitride (SiN/sub x/) gate insulator using three stacked layers: very thin laser of hydrogenated amorphous silicon (a-Si:H), SiN/sub x/ and laser annealed poly-Si. After patterning thin a-Si:H/SiN/sub x/ layers, gate, and source/drain regions were ion-doped and then Ni layer was deposited. This structure was annealed at 250/spl deg/C to form a NiSi silicide phase. The low resistive Ni silicides were introduced as gate/source/drain electrodes in order to reduce the process steps. The poly-Si with a grain size of 250 nm and low resistance n/sup +/ poly-Si for ohmic contact were introduced to achieve a high performance TFT. The fabricated poly-Si TFT exhibited a field effect mobility of 262 cm/sup 2//Vs and a threshold voltage of 1 V.