Analysis and Reduction of Kink Effect in MILC-TFTs

Impact ionization is the main cause of the kink effect in the saturation region of the output characteristics of the field effect transistors. In thin film transistors (TFTs) the kink effect is enhanced due to the presence of traps. The larger the number of traps, the larger the kink effect at a given drain bias. It is observed that the kink effect in conventional metal induced laterally crystal-lized (cMILC)-TFTs occurs at a lower drain bias than that in solid phase crystallized (SPC)-TFTs under the same gate drive. This is shown to result from the overlapping of the MIC/MILC interface and the drain metallurgical junction. Conse-quently, the kink effect can be reduced by eliminating the overlap.