DESCRIPTION OF THE RELATED ART [0002] Conventionally, as typical examples of a thin film transistor (TFT) formed on an insulating substrate such as glass or quartz, a hydride amorphous silicon TFT and a polycrystalline silicon TFT are known. [0003] Of these TFTs, the hydride amorphous silicon TFT can be manufactured under a condition of maximum temperature of about 300??? C. by using an inexpensiv