Patent ID: 7238557
Filing Date: 2007-07-03
Classification: H01L

Abstract:
1. A method of manufacturing a semiconductor device comprising: forming a first amorphous semiconductor layer over a substrate; adding a metal element for reducing a crystallization energy of the semiconductor to a selected portion of the first amorphous semiconductor layer; crystallizing the first amorphous semiconductor layer by a heating treatment to form a first crystalline semiconductor layer; patterning the first crystalline semiconductor layer to form at least one patterned first crystalline semiconductor layer; forming a second amorphous semiconductor layer on the patterned first crystalline semiconductor layer; patterning the second amorphous semiconductor layer to form at least one patterned second amorphous semiconductor layer having a first region overlapped with the patterned first crystalline semiconductor layer and a second region which is not overlapped with the patterned first crystalline semiconductor layer; and crystallizing the patterned second amorphous semiconductor layer, wherein in crystallizing the patterned second amorphous semiconductor layer, an irradiated region of a continuous wave laser beam is moved from the first region to the second region; wherein the first region is used as at least one of a source region and a drain region of a thin film transistor; wherein the second region is used as a channel forming region of the thin film transistor, and wherein the second amorphous semiconductor layer is thinner than the first amorphous semiconductor layer.