Display device comprising a TFT with a barrier metal formed of a first layer and a second layer wherein an amount of oxygen in the first layer is larger than in the second layer

A liquid crystal display device comprising:

• scanning lines extended in a first direction and arranged in a second direction;
• video signal lines extended in the second direction and arranged in the first direction;
• and
• pixels, each of which is formed in an area surrounded by one of the scanning lines and one of the video signal lines, each of the pixels including a switching TFT, a display area including a pixel electrode, and a driving TFT formed in a driving circuit which includes a semiconductor layer at the periphery of the display area;
• wherein a source electrode connected with the semiconductor layer of the driving TFT is formed of three layers comprising a barrier metal, an Al-containing metal and a cap metal, and
• wherein the barrier metal is formed of a first layer in contact with the semiconductor layer of the driving TFT and a second layer in contact with the Al-containing metal;
• wherein each of the first layer, the second layer, and the cap metal is formed of a metal comprising a high melting point metal, and
• wherein an amount of oxygen in the first layer is larger than an amount of oxygen in the second layer.