A CF4 plasma treatment on solid-phase-crystallized (SPC) poly-Si thin-film transistors ( TFTs ) has been demonstrated. Using this technique, fluorine atoms can be introduced into the poly-Si film to passivate the defects, and hence, the device performance of the SPC poly-Si TFTs can be significantly improved. The fluorinated SPC poly-Si TFTs exhibit a good subthreshold slope, low threshold voltage, and high field effect mobility. Moreover, the fluorinated SPC poly- Si TFTs also exhibit an improved hot-carrier-stress immunity, which is due to the strong Si-F bonds formed in the poly-Si channel region. (c) 2005 The Electrochemical Society.