An array substrate for a display device and its fabrication method are disclosed. The array substrate for a display device includes: a gate wiring and a gate electrode connected to the wiring formed on a substrate; a gate insulating layer formed on the gate electrode; an active layer and a barrier metal layer stacked with the gate insulating layer interposed therebetween on the gate electrode; a data wiring formed on the barrier metal layer and source and electrodes connected to the data wiring; a passivation film formed on the source and drain electrodes and the data wiring and having a contact hole exposing a portion of the drain electrode, the barrier metal layer and the active layer; and a pixel electrode formed on the passivation film and being in contact with the drain electrode and the barrier metal layer including the active layer.