Patent ID: 7535065

Claim:
A thin film transistor device comprising: a substrate; a first thin film transistor formed on the substrate and having a single layer first gate electrode, a first insulating film as a first gate insulating film and a first laminated film formed directly on the first gate electrode; and a second thin film transistor formed on the substrate and having a single layer second gate electrode and a second laminated film formed directly on the second gate electrode, said second thin film transistor also having the first laminated film and the first insulating film as a second gate insulating film, wherein a material of the first gate electrode of the first thin film transistor is selected to include any one element of molybdenum, titanium, chromium, tungsten and tantalum as a main component, and a material of the second gate electrode of the second thin film transistor is selected to be different from the material of the first gate electrode and include any one element of aluminum, silver and copper as a main component, wherein the material of the first and second gate electrodes of the first and second thin film transistor are selected so that the second gate electrode of the second thin film transistor has a lower resistance and a lower melting point than the first gate electrode of the first thin film transistor.