Patent ID: 7776669

Claim:
A method of fabricating a thin film transistor (TFT), comprising: preparing a substrate including a first region, a second region adjacent to the first region, and a third region adjacent to the second region; forming an amorphous silicon layer on the first region, second region, and third region of the substrate; doping a first impurity containing boron into the amorphous silicon layer of the first region; forming a crystallization inducing material on the amorphous silicon layer of the first region; applying crystallization energy to the amorphous silicon layer, and crystallizing the amorphous silicon layers of the first region, doped with the first impurity containing boron and having the crystallization inducing material formed thereon, and the second region adjacent to the first region to form polycrystalline silicon layers of the first and second regions; crystallizing the amorphous silicon layer of the third region adjacent to the polycrystalline silicon layer of the second region to form a polycrystalline silicon layer of the third region using a laser crystallization method; and patterning the polycrystalline silicon layers of the first region, the second region, and the third region to form a semiconductor layer from the polycrystalline silicon layer of the third region.