Patent ID: 8817200

Claim:
The 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; pixels, each of which is formed in an area surrounded by one of the scanning lines and the video signal lines, each of the pixels including a switching TFT for switching a video signal supplied to a pixel electrode; and, driving TFTs, each of which includes a semiconductor layer, at the periphery of a 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, wherein the Al-containing metal is formed on the barrier metal, and the cap metal is formed on the Al-containing metal, wherein the barrier metal is formed of a first layer in contact with the semiconductor layer of each of the driving TFTs and a second layer in contact with the Al-containing metal, and wherein each of the first layer, the second layer, and the cap metal is formed of a metal comprising a high melting point metal wherein the thickness of the first layer is thicker than the thickness of the second layer, and wherein the first layer is denser than the second layer.