High mobility poly-Si TFT by a new excimer laser annealing method for large area electronics

A high-mobility (280 cm/sup 2//V-s), high-throughput poly-Si TFT (thin-film transistor) formed using a low-temperature process (≦ 600 degrees C) has been achieved through a novel excimer laser annealing method. The method uses thin, active-layer poly-Si film (500 AA) and involves controlling the solidification process of molten Si by low-temperature (≦ 400 degrees C) substrate heating during laser annealing. Poly-Si film grain formed by this process is radically larger in size, and has minimal internal defects. The maximum grain size is over 5000 AA, and uniformity in field effect mobility was found to be +or-10% within the effective laser irradiation area.