A method of fabricating an array substrate for a display device includes: forming a buffer layer on a substrate having a pixel region; sequentially forming a gate electrode of impurity-doped polycrystalline silicon, a gate insulating layer and an active layer of intrinsic polycrystalline silicon on the buffer layer in the pixel region; forming an interlayer insulating layer of an inorganic insulating material on the active layer; sequentially forming a source barrier pattern, a source ohmic contact layer and a source electrode on the interlayer insulating layer, sequentially forming a drain barrier pattern, a drain ohmic contact layer and a drain electrode on the interlayer insulating layer, and sequentially forming a first dummy pattern, a second dummy pattern and a data line on the interlayer insulating layer; forming a first passivation layer on a surface of the interlayer insulating layer including the source electrode, the drain electrode and the data line formed thereon; forming a gate line on the first passivation layer; forming a second passivation layer on a surface of the first passivation layer including the gate line formed thereon; and forming a pixel electrode on the second passivation layer.