High-mobility poly-Si TFT's fabricated by a novel excimer laser crystallization method

High-mobility poly-Si TFTs (thin-film transistors) were fabricated by a novel excimer-laser crystallization method using dual-beam irradiation. The field effect mobility of the TFT was as high as 380 cm/sup 2//V-s. The origin of high mobility was the large grain size (2 mu m) of poly-Si film obtained by the method used. Si(50 nm)/SiO/sub 2/(80 nm)/Si(100 nm) structure was deposited over a quartz substrate and irradiated by an ArF excimer laser at 300 mJ/cm/sup 2/ on both front and back surfaces at the same time. Bottom-gate TFTs were fabricated using the top Si layers as active layer; SiO/sub 2/ and bottom Si layers were used as gate insulator and gate electrode, respectively; aluminum as source/drain electrodes were directly deposited over the active layer.