Method of manufacturing thin film transistor having lightly doped drain regions

Abstract

Provided is a method of manufacturing a thin film transistor, the method comprising: forming an amorphous silicon layer on a substrate; forming a polysilicon layer by crystallizing the amorphous silicon layer; forming a mask structure that masks a portion of the polysilicon; forming a source and a drain region and a channel region interposed between the source and the drain regions in the polysilicon layer; injecting impurities having a first concentration using an ion beam implantation into one end and the other end of the polysilicon layer which are not covered by the mask structure. The ends of the polysilicon layer with the mask thereon is then subjected to ion bombardment to increase the level of impurities in the source and drain regions while at the same time shrinking the size of the masked regions.