Abstract: A method is provided for fabricating a thin film transistor on a substrate. The method includes the steps of forming an active layer having a channel region on the substrate, forming an impurity-blocking mask covering the channel region and portions of the active layer outside the channel region adjacent the channel region, and doping impurities of a first conductivity type at a high density into portions of the active layer uncovered by the impurity-blocking mask to form impurity-doped regions in the active layer. The method further includes the steps of removing the impurity-blocking mask and thereafter performing a plasma treatment on the resultant structure using a plasma gas containing impurities of the first conductivity type to form LDD regions in the active layer between the channel region and the impurity-doped regions.

Abstract: A thin-film transistor liquid crystal display includes a substrate, an active layer on the substrate, having first and second impurity regions and first, second, and third non-impurity regions, gate insulating layer on the active layer, first and second electric field control layers on the second and third non-impurity regions, respectively, first and second subsidiary gate electrodes on the first and second electric field control layers, respectively, and a main gate electrode on the gate insulating layer, the main gate electrode contacting the first and second subsidiary gate electrodes and the first and second electric field control layers, respectively.