Patent ID: 6670224
Filing Date: 2003-12-30
Classification: H01L

Abstract:
A method of forming a thin film transistor, said method comprises the following steps of:forming a buffer layer on an insulating substrate; forming a polycrystalline thin film on said buffer layer; forming a fist photoresist pattern on said polycrystalline thin film; etching said polycrystalline thin film to form an active area while using said first photoresist pattern as a mask; removing said first photoresist pattern; forming an insulating layer on said buffer layer and said active area; forming an amorphous silicon layer on said insulating layer; forming an amorphous silicon germanium layer on said amorphous silicon layer; forming a second photoresist pattern on said amorphous silicon germanium layer; projecting light through a back side of said insulating substrate to pattern said second photoresist layer while using said active area as a mask; etching said insulating layer, said amorphous silicon germanium layer and said amorphous silicon layer to form an gate electrode while using said second photoresist pattern as a mask; removing said second photoresist pattern; performing an ion implantation into said active area to form a source/drain region using said gate electrode as a mask; forming a conductive layer on said gate electrode, said source/drain region and said buffer layer; performing a thermal process to make said conductive layer react with said gate electrode and said source/drain region; and removing un-reacted portions of said conductive layer.