POLYSILICON THIN-FILM TRANSISTORS WITH UNIFORM PERFORMANCE FABRICATED BY EXCIMER LASER ANNEALING

Uniform performance in poly-Si thin-film transistors (TFTs) has been successfully achieved by excimer laser annealing. Mobility and its uniformity over a substrate were 59+/-3 cm2/V.S for n-channel TFTs and 45+/-5 cm2/V.s for p-channel types. To achieve uniform performance, we combined step annealing that uses two energy levels, and small-pitch annealing that moves a beam forward by a small pitch. The proposed method can improve surface morphology and uniformity of grain size in poly-Si. A 400-stage CMOS shift register composed of these TFTs could operate at 5 V, and attained the speed of 1 MHz at 8 V.