A method for fabricating a liquid crystal display (LCD) device include: forming a gate electrode on a substrate; forming a gate insulating layer on the substrate; forming a primary active layer having a tapered portion to a side of a channel region of the primary active layer on the gate insulating layer, and forming source and drain electrodes on the primary active layer; and forming a secondary active layer made of amorphous zinc oxide-based semiconductor on the source and drain electrodes and being in contact with the tapered portion of the primary active layer, wherein the primary active layer is etched at a low selectivity during a wet etching of the source and drain electrodes, to have the tapered portion.