An array substrate for a liquid crystal display device includes a substrate, a gate line on the substrate, a data line crossing the gate line to define a pixel region, a thin film transistor including a gate electrode, an active layer, an ohmic contact layer, a buffer metallic layer, a source electrode and a drain electrode, the thin film transistor being electrically connected to the gate line and the data line and a pixel electrode in the pixel region and connected to the thin film transistor, wherein the active layer is disposed over and within the gate electrode.