Thin film transistor substrate and method of fabricating the same

A thin film transistor substrate, comprising:

• gate wiring disposed on a substrate;
• oxide active layer patterns disposed on the gate wiring, the oxide active layer patterns comprising a first substance;
• data wiring disposed on the oxide active layer patterns and crossing the gate wiring, the data wiring comprising a second substance;
• barrier layer patterns formed between the oxide active layer patterns and the data wiring, the barrier layer patterns comprising a third substance;
• and
• ohmic contact layer patterns disposed between the oxide active layer patterns and the barrier layer patterns,
• wherein the ohmic contact layer patterns and the oxide active layer patterns comprise the same elements, with the ohmic contact layer patterns having a lower oxygen content than the oxide active layer patterns, and
• wherein the data wiring comprises:
• a first layer disposed on the oxide active layer patterns and comprising an alloy of the second substance and the third substance;
• and
• a second layer disposed on the first layer and comprising the second substance.