Thin film transistor and manufacturing method of same, and display device

A thin film transistor comprising:

• a substrate;
• an active layer supported on the substrate, the active layer including a first region, a second region, and a channel region located between the first region and the second region;
• a gate electrode arranged so as to overlap at least the channel region of the active layer with a gate insulating layer therebetween;
• a source electrode electrically connected to the first region of the active layer;
• and
• a drain electrode electrically connected to the second region of the active layer, wherein
• at least the channel region having a layered structure includes:
• a lower oxide semiconductor layer;
• a first metal layer that is continuous, and that is arranged on the lower oxide semiconductor layer and containing substantially no oxygen;
• and
• an upper oxide semiconductor layer arranged on a top surface of the first metal layer, and
• a thickness of the first metal layer is smaller than a thickness of the lower oxide semiconductor layer or a thickness of the upper oxide semiconductor layer.