Significant improvement of device performance was observed for the excimer laser annealed (ELA) poly-Si thin film transistors (TFTs) by the incorporation of fluorine atoms using the ion implantation technique. This is presumably due to the relaxation of mechanical stress at the poly-Si/buffer-oxide interface and the passivation of trap-states in the poly-Si channel region and at the gate-oxide/poly-Si interface. We achieved high performance ELA poly-Si TFTs with a very low off-current of similar to0.26 pA/mum and a very high On/Off current ratio of about 10(8). Moreover, the fluorine ion implantation also greatly improved the reliability of the ELA poly-Si TFTs with respect to the hot-carrier stress, presumably due to the formation of strong Si-F bonds. (C) 2002 The Electrochemical Society.