A display device including a substrate, a source electrode and a drain electrode on the substrate, the source electrode and the drain electrode being spaced apart from each other, a first planarization layer on the source electrode and the drain electrode, a second planarization layer on the first planarization layer, and a first electrode on the second planarization layer. A step difference between a top of the first planarization layer and a top of the drain electrode is 100 Å or less.